NORM '99 - List of Abstracts

Version 4 ( May 24, 1999 )

Note - [image] indicates that there is a structure or figure at that point, all of which are present and generally looking just fine in the text copy that will make up the Abstract Book.

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(paper copy) means we will be xeroxing the abstract as submitted, usually due to the complexity of the structure and/or the absence of a file copy of the structure.

l. PHOTOCHEMISTRY IN SELF-ASSEMBLED MONOLAYERS. Marye Anne Fox, Chancellor, North Carolina State University, Raleigh, NC 27695.

Recent results will be discussed.

2. PI-SWITCHES: MULTI-STATE THERMAL AND PHOTOCHEMICAL SWITCHES DERIVED FROM DIMETHYLDIHYDROPYRENES. Reginald H. Mitchell*, Timothy R. Ward*, and Yunxia Wang, Department of Chemistry, University of Victoria, Victoria, BC V8W 2Y2.

Elaboration of the dimethyldihydropyrene - cyclophanediene (DMDHP - CPD) photoswitch gives compound I, which has two distinct photoisomers accessible from the ground state I. Results will be presented.
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3. THE EMERGING CENTRALITY OF THE DIRECTED ORTHO METALATION REACTION IN SYNTHETIC AROMATIC CHEMISTRY. Victor Snieckus, Department of Chemistry, Queen's University, Kingston, Canada, K7L 3N6.

Recent developments in extensions and diversifications of Directed ortho Metalation (DoM) have included connections to various transition metal catalyzed cross coupling reactions. The discovery of Directed remote Metalation (DreM) led to the generalization of regiospecific strategies to fluorenones, highly substituted biaryls, and polyaryls and polycondensed aromatic systems, and some of their heteroaromatic analogues. Further extension has been feasible to encompass DreM for the construction of substituted thioxanthones, xanthones, acridones, and dibenzophosphorinones. The Grubbs metathesis - DoM connection has allowed the synthesis of aromatics annelated to large heteroatom-containing rings. Aspects of these ongoing projects will be presented.
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4. SPIRO-PHENALENYLS: A NEW TWIST ON AN OLD IDEA. Robert C. Haddon, Departments of Chemistry and Physics, University of Kentucky, Lexington, KY 40506-0055.

We have previously reported the synthesis and solution properties of the spiro-phenalenyls [Tetrahedron 1986, 42, 6293]. These compounds show unusual electrochemistry, and we have provided evidence for an unusual mode of delocalization in these systems. I will discuss our latest results on the solid-state structures and electronic properties of these novel compounds.

5. SYSTEMATICS OF THE EXCITED STATES OF CYCLIC -ELECTRON SYSTEMS: AROMATIC TO ANTIAROMATIC UNDER ONE ROOF. Josef Michl*, Jörg Fleischhauer and Udo Höweler, Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309.

Recent developments in quantum chemistry permit accurate calculations of electronically excited states of conjugated molecules of respectable size. A complement to such calculations on individual molecules is provided by simple models that permit simultaneous treatment of whole classes of molecules, suggest rationalizations of excited state properties, and permit predictions of trends. A generalization of the classical perimeter model will be presented that permits the treatment of the electronic absorption and magnetic circular dichroism of electron systems derived from aromatic as well as antiaromatic perimeters with equal ease and brings to light the similarities as well as the profound differences between the electronic states of these two fundamental classes of cyclic conjugated molecules.

6. GEODESIC POLYARENES: RATIONAL SYNTHESES AND NOVEL PROPERTIES. Lawrence T. Scott*, Dorin V. Preda, Ronald B. M. Ansems, and Hindy E. Bronstein, Department of Chemistry, Boston College, Chestnut Hill, MA 02467-3860.

(paper copy)

7. TETRATHIAFULVALENOPHANES AS NOVEL ELECTRON DONORS. Tetsuo Otsubo, Faculty of Engineering, Hiroshima University, Higashi-Hiroshima, 739-8527, Japan.

(paper copy)

8. NANOPOROUS MATERIALS FOR INTERLAYER DIELECTRICS IN ULSI DEVICES. C. Pan, B. L. Sun, J. N. Cox, and C. Chiang, Intel Corporation, Components Research, 3065 Bowers Avenue, Santa Clara, CA 95052.

An interlayer dielectric (ILD) thin film with a reduced dielectric constant (k) can improve interconnect performance in ULSI devices by reducing signal delay within and cross-talk between the metal lines it separates. The dielectric constant is 4 for silica, which is widely used as ILD currently, 3-4 for fluorinated silica, 2-3 for organic polymers and organosilane, 1.5-2 for porous organic polymers and silica, and k~1 for air. Our primary interest here is nanoporous silica and organic polymers. A major challenge for using nanoporous materials as ILD is mechanical strength. Various chemical structures have been engineered and film deposition processes have been developed to improve the mechanical strength of the materials. One order of magnitude increase in modulus has been achieved. The ultimate goal is to understand the relationship between property and chemical structure and to engineer promising materials as low k ILD.

9. ASSEMBLY OF NANOPARTICLES ON BIOMOLECULAR SCAFFOLDS: THE INFLUENCE OF POLYPEPTIDE SCAFFOLDS ON ASSEMBLY STABILITY AND THE CHARACTERISTICS OF ELECTRON TRANSPORT. Laura Clarke**, Martin N. Wybourne**, Jana Mooster, Leif O. Brown, Scott M. Reed, and James E. Hutchison*, Department of Chemistry, University of Oregon, Eugene, OR 97403-1253 and **Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755.

The novel electronic properties (e.g., Coulomb blockade) of nanometer scale assemblies of metal nanoparticles make them potentially useful in nanoelectronic devices and extremely sensitive chemosensors. To date, no straightforward and reproducible methods are available for the fabrication of low-dimensional nanoparticle assemblies. Our method of nanofabrication involves the assembly of functionalized metal nanoparticles onto rigid biomolecular scaffolds on an insulating substrate. Our previous investigations of unpatterned nanoparticle thin films provided clear evidence of Coulomb blockade at room temperature, but the response was unstable over time. In this paper we present results for two-dimensional arrays of gold nanoparticles assembled onto a poly-L-lysine scaffold layer. The assembly process provides a simple, chemical method to immobilize the particles and thus stabilize the electrical response (Coulomb blockade) of the array. In addition to stabilizing the array, the polypeptide scaffold is found to mediate one-dimensional electron transport through the film.

10. BIOMOLECULAR TEMPLATING OF GOLD NANOPARTICLES. Scott M. Reed*, Walter W. Weare, Leif O. Brown, Marvin G. Warner, and James E. Hutchison*, Department of Chemistry, University of Oregon, Eugene, OR 97403-1253

Assembly of functional electronic devices on the nanometer scale will require the development of new methodologies for assembly. In our approach, biological molecules with well understood self-assembly are used as templates for the design of nanoelectronic devices. Our synthesis of 1.4 nm gold nanoparticles passivated with alkanethiols has already been described. Here we will present methods of incorporating organic molecules that have a known affinity for biomolecules into the passivating shell of gold nanoparticles. The terminal functionalizations of these thiols are ligands that are known to have an affinity for specific biomolecules. In one case, a known DNA intercalant is incorporated into the ligand shell. In another case, a nitrilotriacetic acid functionality is incorporated into the ligand shell enabling site specific binding to histidine residues in proteins. These functionalized nanoparticles and the resultant assemblies are analyzed by a variety of surface techniques including TEM, AFM and X-ray Photoelectron Spectroscopy.

11. SELF-ASSEMBLED MONOLAYERS ON MESOPOROUS SUPPORTS: SYNTHESIS OF NANOSCALE HYBRID MATERIALS AND THEIR APPLICATIONS. Glen E. Fryxell,* Jun Liu, Tom S. Zemanian, Teresa A. Hauser, James A. Franz, Kentin Alford, Li-Quong Wang; Pacific Northwest National Laboratories, P.O. Box 999, Richland, WA 99352.

The advent of mesoporous ceramics has provided rapid access to readily manipulated, high surface area supports, in which the porosity is both open and accessible. We have chosen to use these materials as a foundation upon which to build terminally functionalized self-assembled monolayers, thereby creating an ordered molecular hierarchy. This 3-dimensional molecular architecture can provide a highly uniform chemical interface, of extremely high surface area. The nuances of these syntheses will be discussed, as will certain applications of these nanoscale hybrid materials as environmental sorbents.

12. ATOMIC LAYER EPITAXY OF Ta2O5-BASED COMPOSITE THIN FILMS AS GATE DIELECTRICS. Hui Zhang, Douglas Skinner and Raj Solanki*. Department of Electrical and Computer Engineering, Oregon Graduate Institute of Science and Technology, Portland, Oregon 97291.

Atomic layer epitaxy (ALE) as a self-limiting thin film growth process can be used to produce ultra thin films on large areas with good conformality and reproducibility. The self-controlling feature of ALE allows us to grow multilayer structures of dielectric thin films at low temperatures in a continuous process. In this paper the use of ALE in deposition of Ta2O5, HfO2, ZrO2 thin films and their nanolaminates on silicon substrates at 300oC will be presented. Metal-chlorides and water were used as precursors. Material (TEM, x-ray) and electrical (dielectric constant, leakage current) properties of these films were evaluated.

13. FORMATION OF SUB-MICRON SCALE FEATURES USING COPPER ELECTRO-DEPOSITION. Jonathan D. Reid, Novellus Systems. 26277 SW 95th Ave, Wilsonville, OR 97070.

Copper is now widely accepted as the interconnect material of choice in future integrated circuit device generations. A preferred method for interconnect feature formation utilizes copper electrodeposition onto thin copper layers previously formed by vapor deposition processes. Complete void free filling of features which may be 5-10 times deeper than they are wide presents a significant challenge to traditional electroplating technology. In order to avoid pinch-off and subsequent void formation, an electrodeposition process must proceed at a rate near the base of the features which is accelerated to several times the rate of deposition at the top of the features. Such behavior has been achieved using classical copper sulfate/sulfuric acid plating solutions in which the rate of deposition is controlled as a function of geometric location by selective adsorption of organic molecules. This paper describes classes of molecules with catalytic and inhibitory effects on the deposition process which may be added at specific concentrations to electroplating solutions to enable filling of 0.12 micron width, 9:1 aspect ratio features. The effect on filling of various factors including organic species and cupric ion diffusion rates and concentrations, temperature, current density and waveform., and agitation will be discussed.

14. RECENT DEVELOPMENTS IN THIN FILM INTERFACE ADHESION MEASUREMENT TECHNIQUES. Tracey Scherban, Safaa El-Mansy*, Milt Jaehnig, Intel Corporation, Hillsboro, Oregon, Brad Sun, Qing Ma, Quan Tran, Intel Corporation, Santa Clara, California and Jose M. Sanchez, Reyes Elizalde, CEIT, San Sebastian, Spain.

The mechanical integrity of thin film interfaces is of critical importance to semiconductor device reliability. Strong interfaces are required to prevent thin film delamination which can lead to electrical failure. This paper reviews new techniques developed to better characterize thin film interface adhesion strength. These techniques represent a significant improvement over previous methods, such as the tape test. Four point bending is a quantitative technique in which a sandwich structure is loaded in flexure, resulting in crack propagation to weak interfaces. Cross-sectional nano-indentation (CSI) is a quick, qualitative technique to assess delamination based on interaction of indentation cracks with thin film interfaces. The chemistry of the interface can strongly modulate the mechanical strength. The use of surface chemical analysis techniques, such as X-ray Photoelectron Spectroscopy (XPS), in conjunction with mechanical measurement techniques, represents a powerful tool in understanding and optimizing thin film interface properties. Recent adhesion results for multilayer structures consisting of dielectric thin films will be reviewed.

15. SPECTROSCOPIC ELLIPSOMETRY AS A PROBE FOR THE MICROSTRUCTURE OF POROUS THIN FILMS. H. Zhang, Department of Electrical and Computer Engineering, Oregon Graduate Institute, Beaverton, OR 97006, and J. Neal Cox*, Components Research, Intel Corp., Hillsboro, OR 97124.

Spectroscopic Ellipsometry (SE) is used routinely to determine thicknesses and optical properties of thin films. Application to the SE data of more detailed models provides with varying degrees of success details about the microstructure of inhomogeneous, porous films. For one film type, SE revealed a moderate density of micrometer-scale voids. A model of surface roughness was consistent with the rupturing of these voids to the surface. For a series of polyimide films prepared with varying densities, the modelling of the SE data was more ambiguous. Nevertheless, trends in the SE data were observed and progress on the development of a comprehensive model are discussed. For "nanoporous" films, which supposedly contain very high densities of nanometer-scale voids, the SE data is best represented by models of homogeneous films with well-behaved optical properties that differ from that of their non-nanoporous counterparts.

16. RAMAN SPECTROSCOPY: A UNIQUE METHOD FOR PROCESS CONTROL. Mike Carrabba*, Steve Barnett, Rick Bormett* and Mark Pavlosky*, Renishaw, Inc. 623 Cooper Ct., Schaumburg, IL 60173.

Raman spectroscopy can be used to identify and quantify molecules via their characteristic vibrational signatures. For many years the Raman technique has been mainly used in the research laboratory. With the recent advances in charge coupled device (CCD) detectors, optical filters, diode lasers, and fiber optics, Raman spectroscopy has started to become a reliable method for process control. This paper will review the Raman technique and describe the use of Raman spectroscopy for the control and management of industrial processes.

17. REAGENT-BASED OPTICAL CHEMICAL SENSORS: REAL WORLD POTENTIAL AND PERFORMANCE. Michael D. DeGrandpre* and Matthew M. Baehr, Department of Chemistry, The University of Montana, Missoula, MT 59812.

An enormous amount of research has been devoted to the development of optical chemical sensors over the past 15-20 years. One group of sensors within this category, reagent-based optical chemical sensors, or ROCS, has not met with widespread commercial success, largely due to drift problems and inconsistent sensor-to-sensor behavior. If these limitations could be overcome, ROCS could operate without the need for calibration - a highly desirable, but as of yet unattainable goal. Our work has focused on the development of ROCS for autonomous in situ measurements of seawater pCO2 (partial pressure of CO2), an application where it is very difficult to perform periodic calibrations. The pCO2 sensor developed from this work has demonstrated exceptional long-term stability and the performance characteristics suggest that calibrations could become unnecessary. We show through response comparisons of identically-designed sensors and long-term studies that calibration-free operation is indeed feasible. The theoretical response, determined from thermodynamic characterization of the indicator solution, also predicts the observed calibration-free performance. Other absorbance-based sensors, such as optrodes, can be designed and operated in a similar fashion, making calibration-free ROCS available for a wide range of industrial, biomedical and environmental applications.

18. ANALOG CHEMOMETRICS: NEW METHODS FOR IMPROVING OLD SENSORS. Karl S. Booksh* and Marc K. Boysworth, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287.

Propagation of errors theory states that in the extreme cases of poor signal to noise or high spectral overlap, employment of digitized spectra for multivariate regression is not optimal for minimizing errors in analyte quantitation. In the particular with scanning and filter-wheel spectrometers, digitization of entire spectra results in a distribution of errors across each spectrum that is independent of the importance of each digitized wavelength for determination of analyte concentration. The errors imbedded in each digitized channel are hence magnified during multiplication of the digitized spectrum with the previously calculated regression vector; there is no assurance that the channels with the best signal to noise will also be the most important channels for regression. With instrumental responses containing errors that are predominantly independent of signal intensity, the error of quantitation can be statistically reduced by adjusting the scanning rate at each wavelength to mimic the relative importance of the wavelength for multivariate regression will integrating the detector throughout the entire scan. This, in effect, performs an analog computation of the dot product of the spectrum with the regression vector on the detector. The benefits of such "analog regression" and its extension of "analog variable selection" will be demonstrated with data collected from a fiber optic, acousto-optic tunable filter based spectrometer and supported by Monte Carlo simulations.

19. COST EFFECTIVE LIQUID CHROMATOGRAPHY THROUGH WATER MOBILE PHASE AND MICROFABRICATED INSTRUMENTATION. Paul G. Vahey and Robert E. Synovec*, Department. of Chemistry, University of Washington, Seattle, WA 98195.

The development of cost effective instrumentation and methodology for process liquid chromatography is reported. The use of a 100% water mobile phase is a departure from current reversed phase liquid chromatography (RP-LC), which usually involves organic solvents. Analysis times and selectivities can be comparable traditional RP-LC separations which employ a C18 stationary phase, with an organic solvent modified mobile phase. Unique advantages result from the low background signal of water in absorbance, Raman, and conductivity detection. A new direction in cost-effective chromatography is microfabricating chromatographic devices. A rapid prototyping technique known as soft lithography, is used to create channels 100 µm wide by 10 µm deep. At these dimensions, high separation efficiencies can be achieved with operating pressures below 5 psi, and solvent consumption under 2.5 mL per week. Current research is focused on modifying channel surfaces and developing on-column detection, to broaden the scope of applications.

20. LIQUID CHROMATOGRAPHY WITH A WATER MOBILE PHASE COUPLED TO HIGH-SPEED CAPILLARY GAS CHROMATOGRAPHY. Wes C. Quigley*, Carlos G. Fraga, and Robert E. Synovec*, Department of Chemistry, University of Washington, Seattle, WA 98195.

A chemical analyzer will be reported based upon coupling liquid chromatography (LC) with a water mobile phase via a novel interface to high-speed capillary gas chromatography (GC). The interface preserves the temporal information of the LC separation, thus a comprehensive two-dimensional LC x GC separation is obtained. LC usually requires organic solvent mobile phase modifiers, so the current work is a departure from typical practice of LC due to the 100% water mobile phase. Separations of a wide variety of compounds have been achieved. A water mobile phase simplifies instrumental requirements, thus enhancing separation and detection strategies. This broadens the scope of LC to on-line process analysis and field monitoring applications by improving safety and minimizing waste. Combining this analyzer with chemometric analysis will be explored.

21. THE USE OF RAMAN SPECTROSCOPY AS A DETECTOR FOR LIQUID CHROMATOGRAPHY. Brian J. Marquardt and Lloyd W. Burgess*, Center for Process Analytical Chemistry, University of Washington, Seattle, WA 98195.

Historically, Raman spectroscopy has not been widely used for process analysis for a variety of reasons, mainly its lack of sensitivity. In this presentation, we will discuss our efforts to effectively develop a highly sensitive Raman detector for liquid chromatography (LC). An inline Raman detection cell has been developed for LC analysis and it is compatible with the typical elution volumes of capillary LC. The detection cell greatly enhances the sensitivity of a typical Raman measurement without resorting to surface enhancement or resonance approaches. By coupling the separation achieved in a liquid chromatogram with the vibrational information gleaned from Raman detection, one can more easily deconvolute and identify individual chemical species in a complicated sample matrix. The resultant, relatively fast, selective and sensitive analysis allows for the collection of information rich multivariate data.

22. OPTICAL LOW COHERENCE REFLECTOMETER FOR PROCESS CONTROL. Simonida R. Thurber, Paul H. Shelley*, Anatol Brodsky, and Lloyd W. Burgess*, Center for Process Analytical Chemistry, University of Washington, Seattle, WA 98195-1700.

Optical Low Coherence Reflectometer is a test and measurement instrument used in the optical communications industry. It uses single mode fibers as both the test probe (fixed mirror equivalent) and reference (moving mirror equivalent) legs of a fiber optic Michelson interferometer. The optical design is based on low coherence (broad bandwidth) light that results in a nominal peak width of 10 microns for a discrete reflection of the 1.3 micron source beam. The Reflectometer has been investigated for a number of potential material analysis applications at the Center for Process Analytical Chemistry (CPAC). The studies include: thickness measurements of components within multiple layer polymer films, simultaneous thickness and refractive index measurements of clear coatings, determination of thickness of highly scattering coatings on both conducting and non-conducting materials, monitoring of paint curing, and scattering in dense liquid suspensions, including the on-line determination of the "degree of doneness" in an attrition milling process (without dilution).

23. SINGLE FIBER KAPPA NUMBER ANALYZER. Carstern Bruckner*, John Robinson, Kuntinee Suvarnakich, Richard Gustafson*, and James Callis*, Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700.

An on-line epi-fluorescence optical instrument has been designed to measure the lignin content of individual wood fibers at high rates of speed for a pulping process. The instrument will be able to measure the heterogeneity of the pulp; such information can greatly assist in process optimization. The current Kappa Number Test, which measures lignin content, is time consuming and only determines an average kappa number over a large population. Our new method correlates kappa number with fiber fluorescence. Acridine Orange is bound to wood fibers. Fiber fluorescence is green at low kappa numbers, and becomes red as lignin content increases. An image acquisition and analysis package has been developed to quantify the fiber fluorescence measured with two CCD cameras, one of which measures the green fluorescence, and the other the red. By taking the ratio of red to green fluorescence, we obtain an index that can be correlated with kappa number.

24. MEASUREMENT OF THE MATERIAL DEPENDENCE OF ELECTRON TRANSFER UPON PEPTIDE MATERIAL. Robert S. Clegg and James E. Hutchison*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403-1253.

The role of proteins as molecular spacers in photosynthesis and mitochondrial respiration makes the dependence of electron transfer (ET) on the intervening medium an important problem. Others have measured the heterogeneous ET rate constant ket across alkanethiol self-assembled monolayers (SAMs) on metal electrodes. We have developed well-ordered, peptide-containing SAMs and have measured ET kinetics across the peptide spacers. Using a battery of characterization methods, methyl-terminated SAMs containing one, two and three amide groups per precursor and hydrophobic alkyl "tails" are demonstrated to be well ordered; thus, a single ET process should predominate in the kinetic measurement. Formation of mixed SAMs containing analogous electroactive precursors having terminal ferrocenecarboxamide groups leads to electrochemically reversible cyclic voltammetry (fwhm £ 96 mV) and chronoamperometry (single exponential current decay), allowing calculation of ket for amide material by independent methods. The ET decay constant b for this model system supports the "preferred pathways" model of ET.

25. ANALYSIS OF PROTEIN-DNA PHOTOCROSSLINKS BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY AND ELECTROSPRAY IONIZATION TANDEM MASS SPECTROMETRY. Douglas F. Barofsky* and Philip R. Gafken, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

Proteins interact with DNA during replication, transcription, recombination, and DNA repair. Identifying the sites of protein-DNA contact within the complex formed during such an interaction is important to understanding the mechanism of the protein's biological function within the cell. We are presently developing a general protocol for probing protein-DNA interfaces that involves purification and mass spectrometric analysis of the nucleopeptide-products of a tryptically digested UV-crosslinked protein-nucleic acid complex. The purified heteroconjugates are in a form that can be readily analyzed by matrix-assisted laser desorption/ionization mass spectrometry and electrospray ionization tandem mass spectrometry to identify the crosslinked amino acids. The protocol is straightforward, reproducible, and should be applicable to the study of many DNA binding proteins. Our presentation will illustrate the application of our protocol to E. Coli uracil-DNA glycosylase photocrosslinked to polydeoxythymidylate.

26. TWO NOVEL METHODS FOR SOLID-PHASE SYNTHESIS OF DNA INTERSTRAND CROSS-LINKS - SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF A NITROUS ACID INTERSTRAND CROSS-LINKED DUPLEX DNA. Eric A. Harwood, Snorri Th. Sigurdsson*, N. B. Fredrik Edfeldt, Brian R. Reid and Paul B. Hopkins*, Department of Chemistry, University of Washington, Seattle, WA 98195-1700.

Nitrous acid promotes the formation of interstrand cross-links in duplex DNA. The cross-link lesion consists of two 2'-deoxyguanosines sharing a common N2 atom (1). Investigation of the structure of nitrous acid cross-linked DNA requires a homogenous sample, not attainable by treatment of duplex DNA with aqueous nitrous acid. We report two new methods for the solid-phase synthesis of interstrand cross-linked DNA and their application for preparation of nitrous acid cross-linked duplex DNA. Phosphoramidite derivatives of 1 were synthesized for both of these methods. The first method required coupling of a mono-phosphoramidite to a single oligonucleotide chain followed by inverse DNA synthesis. In the second strategy, a bis-phosphoramidite was coupled directly to two oligonucleotide chains. The latter strategy was used to synthesize a nitrous acid interstrand cross-linked duplex DNA for structural analysis by 1H-NMR. Initial results of these structural studies are discussed. The synthetic strategy described should be applicable for the synthesis of other cross-linked oligonucleotides as well.

27. DYNAMICS OF NEUROPHYSIN BY 1H NMR AMIDE HYDROGEN EXCHANGE. Ayna N. Alfadhli and David H. Peyton*, Department of Chemistry, Portland State University, Portland, OR 97207-0751.

The neurophysins are homodimeric proteins that exhibit thermodynamic linkage between dimerization and their biological function, the binding of peptide hormones oxytocin and vasopressin. Recent studies have shown that in the neurophysin-hormone precursor, mutation of neurophysin causes diabetes insipidus disease. This disease seems to arises from neurophysin's misfolding. Characterization of neurophysin backbone dynamics is needed to delineate regions that play essential roles in folding and, therefore dictate protein function. Here, we report the analysis of the hydrogen exchange experiments on neurophysin monomer. Our results suggest that the C-domain core of the protein is the folding core of neurophysin, and may be considered as part of an early folding nucleus. The results were verified by the refined NMR solution state structure of the neurophysin's C-domain..

28. AN H-D EXCHANGE STUDY TO TEST THE NUCLEOPHILICITY OF THE BOUND SUBSTRATE IN OXIDATION OF 2,5-DIHYDROXYACETANILIDE BY AN ENZYME FROM STREPTOMYCES MPP3051. Ana C. Barrios and Kevin P. Gable*, Department of Chemistry, Oregon State University, Corvallis, OR 97330.

Dihydroxyacetanilide Epoxidase II from S. MPP3051 has been postulated to operate via a mechanism involving nucleophilic attack of deprotonated, bound substrate on molecular O2. H-D exchange studies reveal that chemical exchange with solvent (water) occurs only under strongly acidic conditions, and that enzymatic exchange at pH 6.5 does not occur. Although not unequivocal proof, these results agree with an alternative mechanism involving one-electron transfer and the intermediacy of superoxide.

29. HAMMETT STUDY ON COMPETITIVE INHIBITORS OF DIHYDROXYACETANILIDE EPOXIDASE I AND II. Kevin P. Gable* and Scott E. Allen, Department. of Chemistry, Oregon State University, Corvallis, OR 97330-4003.

Dihydroxyacetanilide Epoxidase (DHAE) I and II, both dioxygenases, catalyze the conversion of 2,5-dihydroxyacetanilide, 1, into epoxyquinones 2a or 2b. DHAE I and II are unique in that no co-factors are required and enantiomeric products are formed. A series of substituted benzanilides, with a range of Hammett substituent constants, was synthesized and tested as competitive inhibitors of DHAE I and II. From these results, the data suggests that the carbonyl of the amide bond is involved in binding to the active site of DHAE I, whereas in DHAE II the carbonyl does not appear to be involved.
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30. OXIDATION OF PHENOLS BY TYROSINASE: SUBSTITUENT AND DEUTERIUM ISOTOPE EFFECTS. Amrita K. Sahota#, Erik Mork*, Matthew S. Dowling#, Kenneth G. Strothkamp*#, *Department of Chemistry, Lewis and Clark College, Portland, OR 97219 and #Department of Chemistry, Reed College, Portland, OR 97202.

Initial rate studies of the oxidation of a variety of phenols were employed to investigate the tyrosinase mechanism. The effects of m- and p-substitution on the kinetic constants of the reaction were determined. The ability of a phenol to serve as a substrate correlates with the pKa < 9 are competitive inhibitors. A solvent deuterium isotope effect was observed in the oxidation of several phenols, including L-tyrosine. These results indicate that proton transfer from the phenolic hydroxyl is at least partially rate limiting, consistent with the proposal of hydroxyl proton transfer in the tyrosinase mechanism (Biochemistry, 1994, 33, 5730). A small isotope effect was noted in the oxidation of 2,4-dideuterio-L-tyrosine. This suggests that, for L-tyrosine, C-H bond cleavage also affects the kinetics.

31. AQUEOUS CHEMISTRY OF MOLYBDENOCENE DICHLORIDE. Louis Y. Kuo*, Nicholas M. Perera, Laurie Barnes, Christoph Balzarek, and David R. Tyler, Department of Chemistry, Lewis and Clark College*, Portland, OR 97219 and Department of Chemistry, University of Oregon, Eugene OR 97403.

We present an overview of our work on applying the metallocene bis(h5-cyclopentadienyl) molybdenum dichloride organometallic (Cp2MoCl2: Cp = h5-C5H5) towards hydrolyzing organo phosphates in aqueous solution. Cp2MoCl2 readily dissolves in water by losing both chlorides to yield an aquated species that retains the Cp-Mo ligation. This species hydrolyzes activated and unactivated phosphate esters with rate accelerations of 108 for p-nitrophenylphosphate and 104 for dimethyl phosphate. The half-order dependence in Cp2MoCl2(aq) seen for these processes suggests there is a monomer-dimer pre-equilibrium and that the active hydrolytic species is the monomer. An extension of this work involves using Cp2MoCl2(aq) towards hydrolyzing phosphate triesters such as the pesticides parathion and paraoxon (pH 3 and 7). In both cases we see clear evidence for hydrolysis that results from either C-O (parathion + Cp2MoCl2) or P-O bond cleavage O (paraoxon + Cp2MoCl2) that uses water/hydroxide as the nucleophile.

32. THIOPHOSPHATE HYDROLYSIS BY MOLYBDENOCENE DICHLORIDE. Nicholas M. Perera and Louis Y. Kuo*, Department of Chemistry, Lewis and Clark College, Portland, OR 97219.

The pesticides parathion and paraoxon are biochemically similar to many neurotoxins. NMR spectral evidence suggest that bis(h5-cyclopentadienyl) molybdenum (IV) dichloride (Cp2MoC12: Cp = h5-C5H5) degrades parathion and paraoxon via a hydrolytic pathway. This is the first case of an organometallic compound that hydrolyzes organophosphate pesticides in aqueous solution. Cp2MoC12 promotes hydrolytic phosphotriester bond cleavage in paraoxon with rate accelerations of >103 and >106 at pD3 and pD7, respectively. This hydrolysis involves a nucleophilic attack by water or hydroxide onto the phosphorus center (P-O bond cleavage) to yield p-nitrophenol and diethyl phosphoric acid. The DS of activation for this paraoxon hydrolysis is -50 e.u. which suggests an intermolecular pathway. Cp2MoC12 promotes the hydrolytic C-O bond cleavage in parathion with a rate acceleration of 10 at pD7. The hydrolysis of parathion involves a nucleophilic attack by water or hydroxide, but onto carbon instead of phosphorus to yield ethanol and deethyl parathion.

33. FLUORINATED AMIDO COMPLEXES OF ZIRCONIUM AND YTTRIUM. David J. Berg*, Katherine Burrage, and Sheryl Steeves, Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, BC, Canada V8W 3V6.

The synthesis of a series of fluorinated amide ligands (1) and their zirconium (2) and yttrium complexes (3) will be presented. The increased Lewis acidity at the metal center makes complexes typified by 2 excellent Lewis acid catalysts for reactions such as the Meerwein-Pondorff-Verley reduction, nitroaldol condensation and hetero Diels-Alder cyclization. Chiral derivatives of 2 have been prepared and preliminary efforts to use these as asymmetric Lewis acid catalysts will be discussed. Organometallic complexes such as 3 display increased alkene, CO and isocyanide insertion chemistry into the metal-carbon bond when compared to non-fluorinated analogues. In addition, the fluorinated complexes all display significantly enhanced solubility in hydrocarbons over non-fluorinated analogues.
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34. OXIDATIVE ADDITION AND REDUCTIVE ELIMINATION REACTIONS AT Pt(II)/Pt(IV). Karen I. Goldberg, Department of Chemistry, University of Washington, Seattle, WA 98195-1700.

The oxidative addition of a carbon-hydrogen bond to a Pt(II) center has been proposed as the substrate activation step in Pt-catalyzed reactions which functionalize alkanes. Reductive elimination from Pt(IV) to form a carbon-heteroatom bond has been proposed as the product release step. We have been able to directly observe and study these and related oxidative addition/reductive elimination reactions with model Pt(II)/Pt(IV) complexes. Kinetic and mechanistic studies of the reactions will be presented with primary emphasis on the formation and cleavage of carbon-hydrogen, carbon-carbon and carbon-oxygen bonds.

35. RECENT ADVANCES IN COMPUTATIONAL CHEMISTRY: NEW METHODS AND APPLICATIONS TO CATALYSIS, MATERIALS AND BIOCHEMISTRY. William A. Goddard, III, Charles and Mary Ferkel Professor of Chemistry and Applied Physics, Director, Materials and Process Simulation Center (MSC), California Institute of Technology (139-74), Pasadena, CA 91125.

We will summarize recent advances in atomistic simulations involving: quantum chemistry, force fields, and molecular dynamics with applications involving chemistry, materials science, and biochemistry. Topics to be covered will be selected from:
Homogeneous polymerization catalysts
Catalytic activation of small alkanes
Chemisorption and rearrangement of hydrocarbons on noble metal surfaces
Protein folding
Organic chelants for radio-cancer therapy
First principles modeling of gasoline refinery kinetics
Structures and properties of dendritic polymers
Structure and properties of single-wall carbon nanotube ropes
Shock-induced phase transitions in ceramics
Plasticity of metal alloy nanotubes
Reconstruction of GaN surfaces
Wear inhibitors for automobile engines
Scale inhibitors and wax inhibitors for oil pipelines
Melting and glass transformations of metal alloys.

36. ACCURATE THEMOCHEMISTRY VIA LOCAL MULTIREFERENCE PSEUDO-SPECTRAL CORRELATION METHODS. Robert B. Murphy*, Schrödinger, Inc., 121 S.W. Morrison Ave., Portland, OR 97204 and Barry Dunietz and Richard A. Friesner, Department of Chemistry, Columbia University, New York, NY 10027.

We have developed an accurate method for thermochemical calculations based upon single and multi-reference local MP2 methods, LMP2 and GVB-LMP2. In analogy to G2 theory the method uses empirical correlation corrections partitioned into sigma and pi contributions. The pseudospectral correlation methods of this theory have a very favorable cubic scaling with system size allowing applications on systems as large as a carbon C20 cluster with large triple zeta basis sets. Results for heats of formations of molecules in the larger G2 test suite will be presented as well as a study of C20 isomers in comparison to density functional theory.

37. IMPROVED ACCURACY WITH RECENT DENSITY FUNCTIONALS. Mark Stave and James Anchell, Oxford Molecular Group, 14940 NW Greenbrier Parkway, Beaverton, OR 97006-5733.

A number of recently published studies [1,2] describe the development of new exchange-correlation energy density functionals that depend only on the electron charge density and its gradient and, thus, fall within the generalized gradient approximation (GGA). These new functionals enable molecular property predictions that are at least as accurate as those based on hybrid functionals [3], such as B3LYP [4], without introducing any fraction of exact orbital exchange. Consequently, computations involving these new GGA functionals are much faster than those using the hybrid functionals. We report results from calculations using two of these new functionals as implemented in the DGauss density functional program.
[1] M. Filatov and W. Thiel, Molec. Phys. 91, 847 (1997).
[2] F. A. Hamprecht, A. J. Cohen, D. J. Tozer and N. C. Handy, J. Chem. Phys. (submitted).
[3] A. D. Becke, J. Chem. Phys. 98, 5648 (1993).
[4] P. J. Stephens, F. J. Devlin, C. F. Chabalowski, and M. J. Frisch, J. Phys. Chem. 98, 11623 (1994).

38. THE IMPORTANCE OF STATIC CORRELATION IN THE BAND STRUCTURE OF HIGH TEMPERATURE SUPERCONDUCTORS. Jason K. Perry, First Principles Research, Inc., and Schrödinger, Inc., 8391 Beverly Blvd., #171, Los Angeles, CA 90048.

Recently we presented a new band structure for La2-xSrxCuO4 and other high temperature superconductors in which a second narrow band was seen to cross the primary band at the Fermi level. The existence of this second Fermi level band is in complete disagreement with the commonly accepted LDA band structure. Yet it provided a crucial piece of physics which led to an explanation for superconductivity and other unusual phenomena in these materials. In this work we present details as to the nature of the failure of conventional methods in deriving the band structure of the cuprates. In particular, we use a number of chemical analogues to describe the problem of static correlation in the band structure calculations and show how this can be corrected with the predictable outcome of a Fermi level band crossing. A preprint of this work may be downloaded from xxx.lanl.gov/abs/cond-mat/9903088.

39. CORRELATION-CONSISTENT BASIS SETS FOR THE NICKEL ATOM. Douglas L. Strout and Thom H. Dunning, Jr.*, Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, MS K1-96, Richland, WA 99352.

Following the techniques previously applied to main group elements, correlation-consistent basis sets are developed for the nickel atom. Basis sets of double zeta (DZ) to sextuple zeta (6Z) quality are built up by the addition of groups of basis functions based on each function's contribution to the total energy. Benchmark calculations are carried out on the atomic state splittings and electron affinity. Bond lengths, frequencies, dissociation energies, and electron affinities are calculated for nickel-containing diatomics. Coupled-cluster theory (CCSD(T)) is shown to give good results, and relativistic effects are shown to be important.

40. APPLICATION OF NATURAL BOND ORDER ANALYSIS AND NATURAL RESONANCE THEORY TO THE STABILITY AND REACTIVITY OF PEROXYNITROUS ACID CONFORMERS. Bryant A. Gilbert, Department of Chemistry, Portland State University, Portland, OR 97207-0751.

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The nitration and oxidation chemistry of peroxynitrous acid is currently interpreted in terms of the stability of its cis (1) and trans (2) conformations. The results of Natural Bond Order Analysis (NBO) and Natural Resonance Theory (NRT) are used to define the electronic factors responsible for this stability/reactivity relationship. A unified mechanism will be provided which accounts for the nitration and oxidation chemistry of peroxynitrous acid in terms of acid-base chemistry.

41. TRAJECTORY STUDIES OF OH + O COLLISIONS: QUENCHING OF VIBRATIONALLY EXCITED OH. Robert J. Hinde, Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600.

The chemical heating rate of the terrestrial mesosphere is highly sensitive to the rate at which vibrationally excited OH radicals are quenched in collisions with oxygen atoms. However, quenching rate constants for OH (v) + O collisions have not been measured experimentally for v > 1. We present the results of a quasiclassical trajectory study of OH (v) + O quenching collisions and use these results to estimate the quenching rate constants for highly excited (v > 1) OH radicals. We also comment on the role which inelastic OH (v) + O collisions may play in producing the vibrationally cold, rotationally hot OH radicals that have recently been observed in the mesosphere.

42. UV/VIS MULTIPHOTON DISSOCIATION DYNAMICS OF CHROMIUM CARBONYL COMPLEXES. Daniel P. Gerrity, Department of Chemistry, Reed College, Portland, OR 97202.

The UV/visible laser multiphoton dissociation (MPD) of vapor-phase organometallics produces neutral metal atoms in both ground and excited states. We use spontaneous and laser-induced fluorescence techniques to measure the relative product state distribution of the electronic states of atomic Cr produced in the MPD of several chromium carbonyl compounds. The dependence of this distribution on photodissociation wavelength, laser power, ligand complexity, and added buffer gas pressure is being used to explore the dynamics of the MPD process. Evidence will be given for the existence of non-statistical dissociation pathways, and recent work on the effect of added buffer gas pressure on the chromium atom product state distribution will be described.

43. A TIME-RESOLVED RESONANCE RAMAN STUDY OF CHLORINE DIOXIDE PHOTOCHEMISTRY IN WATER AND ACETONITRILE. Sophia C. Hayes, Matthew P. Philpott, Steven G. Mayer, and Philip J. Reid,* Department of Chemistry, University of Washington, Seattle, WA 98195.

The photochemistry of chlorine dioxide (OClO) in water and acetonitrile is investigated using time-resolved resonance Raman spectroscopy. Stokes and anti-Stokes spectra are measured as a function of time following photoexcitation using degenerate pump and probe wavelengths of 390 nm. The time-dependent Stokes intensities are found to be consistent with the reformation of ground-state OClO by subpicosecond geminate recombination of the primary ClO and O photofragments. This represents the first unequivocal demonstration of primary-photoproduct-geminate recombination in the condensed-phase photochemistry of OClO. Analysis of the anti-Stokes decay kinetics demonstrates that intermolecular vibrational relaxation occurs with a time-constant of ~9 ps in water and ~36 ps in acetonitrile. In addition, the appearance of symmetric-stretch anti-Stokes intensity is significantly delayed relative to geminate recombination, suggesting the excess vibrational energy is initially deposited along the asymmetric stretch co ordinate with intramolecular redistribution of this energy occurring in ~5 ps in water and ~20 ps in acetonitrile.

44. SINGLET ENERGY TRANSFER FROM CAROTENOIDS TO CYCLIC TETRAPYRROLES IN ARTIFICIAL PHOTOSYNTHETIC ANTENNAS. Alisdair N. Macpherson and Tomas Gillbro, Umea University S-901 87 Umea, Sweden, and Paul A. Liddell, Ernesto Mariño-Ochoa, Dereck Tatman, Edgardo Durantini, Devens Gust, Thomas A. Moore and Ana L. Moore*, Department of Chemistry and Biochemistry, Arizona State University, PO Box 871604, Tempe, AZ 85287-1604.

Carotenoids serve as light-harvesting pigments in photosynthesis where they absorb blue-green light and transfer energy to chlorophylls. This energy transfer process has been examined in several carotenotetrapyrrole dyads. Transient fluorescence measurements in toluene solution demonstrate that the fluorescent excited state (S2) of the carotenoid in the dyad is strongly quenched compared with the corresponding excited state in a carotenoid model compound. This quenching corresponds to ~70% efficient singlet-singlet energy transfer which matches the quantum yield obtained from steady state fluorescence measurements. The S2 state of the carotenoid is assigned the majority donor state. This observation is consistent with results from other model and natural systems.

45. PROBING INTERFACIAL WATER STRUCTURE BY VIBRATIONAL SUM FREQUENCY. Lawrence F. Scatena and Geraldine L. Richmond*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

The structure and orientation of water molecules at various liquid/liquid interfaces have been probed by Vibrational Sum Frequency Generation. Specifically the region between 1975 cm-1 to 4000 cm-1 has been examined accessing the vibrational modes of H2O and D2O. Our experiments examine the interfacial equilibrium water vibrational structure of a neat interface and the changing water structure with addition of small polar molecules (i.e. CHCl3, CH2Cl2) to the CCl4 phase. We also examine the effect of small, water soluble adsorbate molecules on the structure and orientation of water molecules at and interface. The results begin to give new insight into the changing structure of the liquid/liquid interface where the subphase (CCl4) is composed of a binary mixture of polar and non-polar molecules. These studies also uncover how small adsorbate molecules affect the water vibrational structure and in turn give a molecular picture of the liquid/liquid interface.

46. SUBSTITUENT EFFECTS ON THE HYPERPORPHYRIN SPECTRA OF DIPROTONATED PARA-SUBSTITUTED MESO-TETRAPHENYLPORPHYRINS. James R. Weinkauf, Aaron S. Schweiger, Sharon W. Cooper and Carl C. Wamser*, Department of Chemistry, Portland State University, Portland, OR 97207-0751.

Porphyrins are a class of molecules which consist of four pyrrole groups in a large ring. Modifications of porphyrins include substitution at the meso-carbons by para-substituted phenyl components. In the neutral free-base form, two of the pyrrole nitrogens are hydrogen-substituted while two retain their free pair of electrons. Careful acid titrations allow for protonation of these pyrrole nitrogens and the creation of the acid dication. The acid dications exhibit red-shifted (lowered energy) absorption spectra relative to the free-base porphyrin. These red-shifts increase with the introduction of electron-donating substituents (i.e., methyl, methoxy, hydroxy, amino) of increasingly negative Hammett values. The term hyperporphyrin describes the observation of resonance delocalization of the positive dication charge from the interior pyrrole nitrogens outward to the electron-donating para substituents and the subsequent red-shifted hyperporphyrin spectrum.

47. THE USE OF INTEGRAL EQUATION AND MONTE CARLO TECHNIQUES TO UNDERSTAND THE LIGHT SCATTERING/DENSITY PROFILES OF SUPERCRITICAL FLUID BINARY MIXTURES. Frank G. Baglin*, Tasha E. Palmer, Jill E. Dougherty, Sue K. Murray and Wayne T. Stanbery, Departments of Chemistry and Chemical Engineering, University of Nevada, Reno, NV 89557 and Martin Neumann, Department of Computational Physics, University of Vienna, Vienna, Austria.

Using interaction induced Raman light scattering (iiRLS) to provide intensity/density (I/d) vs. density (d) profiles for both CH4/CO (CO2 or CF4) solute-solvent systems, Monte Carlo (MC) and Integral equation (IE) techniques have been applied to more fully comprehend the radial distribution function (rdf) properties that represent the various densities. In particular, the IE calculations have used only single center LJ molecular parameters whereas the MC use atomic centered LJ parameters and partial charges on the atoms, thus allowing the effects of dipoles and or quadrupoles to be ascertained. Moreover, the IE results have been used to calculate local density numbers which, in turn, allow us to attempt to reproduce the experimental iiRLS results.

48. A CENTRAL LIMIT THEOREM FOR CHEMICAL KINETICS IN COMPLEX SYSTEMS. Joel Z. Bandstra and Paul G. Tratnyek*, Department of Environmental Science and Engineering, Oregon Graduate Institute, Portland, OR 97291.

Reaction kinetics often appear to be first order, even in complex systems that could produce complex rate laws. This is partially due to experimental designs that emphasize initial rates and rate limiting steps, and may also be an artifact of the difficulty in resolving reaction orders from data that contain experimental noise. In addition to these familiar issues, it is also possible that complex systems are inherently more likely to be phenomenologically indistinguishable from first order. This conjecture arises by way of analogy to the central limit theorem (from statistics) wherein the distribution of a random sample, of size n, taken from any density function approaches a normal distribution as n becomes very large. To determine whether something like a "central limit theorem of chemical kinetics" applies to complex systems, we have fit first order kinetics to solutions for non-first order systems of increasing complexity. The results will be illustrated with examples from a variety of applications.

49. PANEL DISCUSSION: WHAT NEW GRADUATES NEED TO KNOW. W. Scott Briggs, Simpson Oregon Overlays, P.O. Box 17307, Portland, OR 97217.

Brief formal presentations will be given by several professional chemists who have taken a wide variety of career paths describing challenges they faced and things they wished that they had known at the start of their employment. In these remarks, the panelists will offer observations of how it "really is" in the world outside academe and what chemists-in-training can do to groom themselves for professional success and job satisfaction after graduation. Adequate time will be available for specific questions from the audience to the panelists on any pertinent concerns, and opportunity also will be available for private discussions with individual members of the panel after the formal session has closed.

50. SOLIDS ARE LIKE PEOPLE: IT'S THE DEFECTS THAT MAKE THEM INTERESTING. Arthur B. Ellis, Department of Chemistry, University of Wisconsin, Madison, WI 53706-1396.

Illustrative examples from materials science and solid-state chemistry will be presented that highlight the role of defects in determining chemical and physical properties of solids. The talk will include several demonstrations.

51. MORE ABOUT SUPERPHANES: NEW SUPERPHANES WITH FOUR- AND FIVE-MEMBERED RING SYSTEMS. Gebhard Haberhauer, Rolf Roers and Rolf Gleiter*, Organisch-Chemisches Institut der Universität Heidelberg, im Neuenheimer Feld 270, D69120 Heidelberg, Germany.

(paper copy)

52. [m.n]CYCLOPHANES AS WORKBENCHES FOR ORGANIC SYNTHESIS. Henning Hopf, Technische Universität Braunschweig, Institut für Organische Chemie, Hagenring 30, D-38106 Braunschweig, Germany.

As spacer molecules [m.n]cyclophanes are unique: they allow positioning of practically any functional group in many clearly defined geometries in three-dimensional space. As a case in point, the preparation of pseudo-geminally substituted [2.2]paracyclophanes will be discussed which are ideal workbenches for the synthesis of stereospecifically substituted cyclobutane derivatives. This topochemical control in solution can be carried out in such a way as to recover the spacer system - which hence serves as a proxy for the crystal lattice - quantitatively.

53. NEW [2.2]PARACYCLOPHANES AND MORE. Armin de Meijere*, Oliver Reiser, Burkhard Koenig, Herwig Buchholz, Burkhard Knieriem, and Karsten Rauch, Institut für Organische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, D-37077 Göttingen, Germany

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Bearing on the motif of [2.2]paracyclophane 1 and its diene 2, a variety of new assemblies such as hydrocarbons 3-9 have been prepared, applying known and newly developed methodology.[1] Some of the new syntheses of such compounds, their structural, physicochemical and chemical properties will be discussed.

[image]

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[1] For recent reviews see: A. de Meijere, B. König, Synlett 1997, 1221-1232; B. König, Topics Curr. Chem. 1998, 196, 91-136.

54. FRONTIERS IN NON-NATURAL PORPHYRIN CHEMISTRY. Emanuel Vogel*, Martin Michels, and Lars Zander, Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, D-50939 Köln, Germany.

(paper copy)

55. CYANO- AND ETHYNYLAZULENES: VERSATILE BUILDING BLOCKS FOR NOVEL MATERIALS. Ahmed H. M. Elwahy, Kai Fabian, Stefan Schmitt, and Klaus Hafner*, Institute of Organic Chemistry, Technical University Darmstadt, D-64287 Darmstadt, Germany.

Although the chemistry of azulenes has been studied successfully for more than six decades, quite a number of conceptually simple azulenoid systems, sometimes with an extended -electron structure, remained unexplored despite their potential utility as building blocks for new functional materials, or as model compounds for an investigation of the relationship between molecular design and electronic structure. Recently we have developed new approaches for the synthesis of ethynylazulenes, which can be easily transformed into a variety of ethynyl- and butadiynyl-bridged polyazulenes. Furthermore, polycyanoazulenes proved to be a new and promising class of electron acceptors, from which CT-complexes and stable radical anions have been obtained. The syntheses, structures, and properties of the novel azulene derivatives will be discussed.

56. THE CARBON DIOXIDE TECHNOLOGY PLATFORM. Joseph M. DeSimone, Department of Chemistry, CB #3290, Venable and Kenan Laboratories, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290 and Department of Chemical Engineering, College of Engineering, North Carolina State University, Raleigh, NC 27695-7905.

What if the electronics industry used specially-designed photoresists that could be deposited using a spin coating process based upon liquid CO2 instead of organic solvents? Also what if this industry didn't have to use hundreds of millions of gallons of water per day to remove sub-micron particles during the manufacture of integrated circuits and flat panel displays? Imagine polymerizing monomers in a continuous stirred tank reactor with the resulting polymers instantly dry, avoiding the trillions of BTUs needed every year to dry commercial polymers made in aqueous reaction media. Imagine an automotive industry that doesn't expose its employees to toxic chlorinated solvents during metal degreasing processes. Imagine a textile industry that doesn't need to use 100 lbs. of water for every 1 lb. of yarn that was dyed. Imagine local dry cleaners that don't need to clean garments in perchloroethylene and local businesses that don't need to pay exorbitant, newly enacted taxes on solvent use or carry newly mandated liability insurance policies. What if the demands on municipal water systems and municipal waste water systems could be dramatically reduced by changes in manufacturing technology? Imagine an educational environment where students become grounded in the fundamentals of their core disciplines, are exposed to cutting-edge, multi-disciplinary science, and can experience the satisfaction and excitement that comes from doing research that makes a difference to society. The discussion will focus on the latest developments from the Kenan Center for the Utilization of CO2 in Manufacturing. In particular, the detailed synthesis and CO2 solution properties of fluorinated and siloxane-based homopolymers and block copolymers will be discussed. The utility of such macromolecules will also be demonstrated for use in coatings (photoresists and textiles), separations, stabilizers for polymerizations, and scaffolds for catalysis. Particular attention will focus on exploiting the compressibility of supercritical CO2 to reversibly form and break-up micelles by pressure-profiling, illustrating a critical micelle density. In addition, methods will be discussed for using supercritical extraction methods to drive step-growth polymerization reactions, both CO2-swollen melt-phase reactions as well as solid-state polymerizations, for the synthesis of polyesters, polyamides, and aromatic polycarbonates.

57. CORRELATED MANY-CHAIN DYNAMICS: ENTANGLEMENTS, SLOW MODES, AND GLASS TRANSITION. Marina Guenza, Department of Chemistry, University of Oregon, Eugene, OR 97403.

When the single polymer dynamics is hindered effectively by the presence of other chains, anomalous dynamics take place detected by the appearance of plateaus in the characteristic time correlation functions. This effect becomes dominant when the polymer molecular weight is high (entanglements) or when the system is supercooled, or when we are looking to highly dense systems. In all these cases motions can take place only through correlated mechanisms involving many chains. In this work we present a rigorous theoretical approach to describe the simultaneous correlated dynamics of several macromolecules. Starting from the Liouville equation, using Mori-Zwanzig projection operator techniques, we derived a Generalized Langevin Equation that contains, in addition to the self term, cross interaction contributions to the frequency matrix and the memory functions. The memory functions are solved using a mode-coupling approach. A self-consistent procedure allows the numerical solution of the diffusive dynamics as a function of the strength of the intermolecular potential. For weak intermolecular interactions the short-time correlated diffusive dynamics cross over to the uncorrelated single chain dynamics, while for strong intermolecular interactions collective diffusion is dominant. This effect is polymer molecular weight, polymer volume fraction, and temperature dependent.

58. EFFECTS OF SOLVENT SYSTEMS UPON THE PHASE CHANGE BEHAVIORS OF POLY(ETHYLENE GLYCOL)-CELLULOSE BLENDS. Xue-Hai Liang, Yuan-Qiang Guo and Lian-Zhen Gu, LCLC, Guangzhou Institute of Chemistry, Chinese Academy of Sciences, P. O. Box 1122, Guangzhou, China 510650.

As reported in a previous paper [1], polyethylene glycol (PEG) blended with cellulose (CELL) was found not to melt into the liquid state, but exhibited a crystalline-amorphous solid-solid phase transition even as the temperature was raised to over its melting point. Recent investigations show that the blends prepared from solution in DMSO/PF and those in DMAC/LiCl have completely different phase change behaviors and different miscibility. In DMAC/LiCl the miscibility of CELL and PEG is poor, the composite obtained exhibits a solid-liquid phase transition and has small transition enthalpy. However, in DMSO/PF, these two polymers have a high level of miscibility, the blend obtained exhibits a solid-solid phase transition and has a large transition enthalpy. It is suggested that the differences of miscibility and the phase change behaviors are caused by the different dissolving mechanisms of CELL and different interactions in the two solutions.
[1] X. H. Liang, Y. Q. Guo, L. Z. Gu, Macromolecules, 1995, 28, 6551-6555.

59. SYNTHESIS OF REGIOREGULAR POLY(4-SUBSTITUTED-2,2¢-BITHIOPHENE)S: POTENTIAL PRECURSORS TO ORGANIZED CONJUGATED POLYMER SOLIDS. Bennett D. Straw, Seth C. Rasmussen and James E. Hutchison*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403-1253.

The optical and electronic properties of conjugated organic polymers are of considerable interest for electronic applications (e.g., in polymeric conductors and field-effect transistors). The degree of order and crystallinity of the solid polymer often dictates the material performance. More highly organized solid-state structures have enhanced electrical conductivity and higher field-effect mobility. Our two-fold approach to enhancing the properties is to reduce the number of polymer side chains and control the regiochemistry of the polymer. These partially substituted, regioregular polymers should form well ordered solid state structures with a higher volume fraction of polythiophene chains than previously reported materials. Evidence for increased order in polymer solutions and solid films have been observed as bathochromic (red) shifts in the optical spectra of regioregular poly(4-substituted-2,2¢-bithiophene)s compared to regiorandom analogs. Regioregular polymers possessing carboxylic acid side chains, e.g. regioregular poly(4-carboxy-2,2¢-bithiophene), allow full characterization of the polymer and make "green" processing, in aqueous solution, possible

60. THERMOREVERSIBLE GELS FOR DELIVERY OF THERAPEUTIC AGENTS. Anna Gutowska*, Kendra A. Bennett, and Darrell R. Fisher, Pacific Northwest National Laboratory, Richland, WA 99352.

Thermosensitive hydrogels were synthesized and characterized as a novel injectable delivery system for cancer treatment. The hydrogels were synthesized with N-isopropyl acrylamide (NiPAAm) copolymerized with acrylic acid (AAc) comonomer. The copolymer gel will contain therapeutic agents such as anticancer drugs and medical radioisotopes at the injection site. Thus the copolymer will allow very high localized drug or radiation doses to tumor tissues with little effect on normal tissues. The release of 5-fluorouracil and bovine serum albumin from the NiPAAm/AAc was studied, as well as the containment of Y-90 within the copolymer. Preliminary experiments in mice and dogs show its promise as a new technology for treating solid tumors. Possible applications include treatment of prostate, pancreatic, liver, brain, and kidney cancers.

61. VAPOCHROMIC SENSORS FOR THE DETECTION OF VOLATILE ORGANIC COMPOUNDS. Leslie K. Moore*, Jay W. Grate, Marie K. Pomije, and Kent R. Mann, Center for Process Analytical Chemistry, Department of Chemistry, Box 351700, University of Washington, Seattle, WA 98195-1700.

Vapochromic materials are highly absorbing/emitting organometallic compounds that exhibit spectral shifts upon exposure to solvent vapors. In this work we studied mixed Pt-Pt salts of the general form [Pt(R-isonitrile)4][Pt(CN)4] where the functional group R is varied to enhance the selectivity of the compound to analytes of interest in industrial process and environmental monitoring. Vapochromism in these salts arises from a highly porous structure that enables the analyte molecule access to the medium sensitive chromophore. This work applies Vapochromic materials to Quartz Crystal Microbalances and Surface Acoustic Wave sensors. Simultaneous optical and acoustic measurements were performed to determine the sensitivity of the compounds to analytes such as dichloromethane, chloroform, benzene, toluene, xylene and water.

62. DYNAMIC SURFACE TENSION SENSOR FOR PROCESS MONITORING APPLICATIONS. Keith E. Miller and Robert E. Synovec,* Center for Process Analytical Chemistry, Department of Chemistry, Box 351700, University of Washington, Seattle, WA 98195-1700.

A sensor is presented that measures dynamic surface tension (DST) in aqueous, flowing systems. Surface tension is related to the surfactant concentration in solution by measuring the changing pressure across the liquid-air interface of drops repeatedly forming at the end of a capillary. A technique is presented that allows for rapid on-line calibration and DST measurement without using optical imaging equipment. This makes the sensor ideal for process control and chemical separation applications. Detection limits in the low ppm are achieved. DST measurements during early stages of drop growth (50 msecs to 1 sec) are achieved, providing insight to kinetic behavior at the liquid-air interface of surface active proteins and polymers. In addition, a novel instrumental adaptation is presented that reduces the volume of the growing drop from 7µL to the 1 to 3 µL range. Since each drop is effectively one detector "flow cell" volume, this reduction in drop volume makes the sensor well suited for microbore LC.

63. GRATING LIGHT REFLECTION SPECTROSCOPY FOR PROCESS MONITORING. Sean A. Smith, Anatol M. Brodsky, Lloyd W. Burgess*, Center for Process Analytical Chemistry, Department of Chemistry, Box 351700, University of Washington, Seattle, WA 98195-1700

Grating Light Reflection Spectroscopy (GLRS) exploits the interaction and light with a transmission diffraction grating in contact with a sample. Light reflected from this interface exhibits a redistribution of optical intensity and phase that depends on the bulk dielectric properties of the sample. Thus, one can conduct an optical transmission measurement in a reflection mode. GLRS is attractive as a process monitor because of its insensitivity to fouling layers (relative to similar techniques such as SPR or ATR), and because it can be used to characterize optically dense (~250 A.U.) and/or heterogeneous sample matrices. Past work has demonstrated the technique's usefulness in discriminating particles with diameters on the order of a few nanometers, which suggests it may also have utility as a molecular weight monitor. Currently, we are developing a micro flow-channel environment to implement GLRS as a liquid chromatography detector and to simulate the monitoring of industrial processes via a "slip-stream" arrangement.

64. LIQUID CORE WAVEGUIDES, CHARACTERIZATION AND APPLICATIONS FOR PROCESS ANALYSIS. Heather C. Edberg, Brian J. Marquardt, and Lloyd W. Burgess*, Center for Process Analytical Chemistry,. University of Washington, Box 351700, Seattle, WA 98195-1700.

Liquid core waveguides are useful in process analysis both as sampling interfaces and as whole sensing systems. These optical waveguides utilize a liquid core material of a higher refractive index than that of the cladding material. There are various cladding materials used in liquid core waveguides, many of which are Teflon-based polymers with indices of refraction from 1.29 to 1.40. With cladding refractive indices lower than that of water (1.33), it is possible to construct aqueous core waveguides. The transmission characteristics of various Teflon clad waveguides have been studied as a function of core refractive index and excitation wavelength. In this presentation we will discuss the application of aqueous core waveguides for both headspace and bulk phase analysis. We have developed specific waveguide sensors for the measurement of hydrochloric acid vapor and dissolved CO2.

65. SONOLUMINESCENCE FOR QUANTITATIVE ANALYSIS. Alex L. Robinson, Anatol M. Brodsky, Lloyd W. Burgess*, Center for Process Analytical Chemistry, Department of Chemistry, Box 351700, University of Washington, Seattle, WA 98195-1700.

Cavitation arises when ultrasonic power of sufficient intensity is applied to a liquid, disrupting the intermolecular bonds. Originating at seed nuclei, cavitation bubbles grow and collapse non-linearly during the rarefaction and compression phases of the acoustic waves, respectively. The rapid collapse of a bubble subjects the vapor contents and liquid-gas interface to temperatures and pressures on the order of 5000 Kelvin and 10,000 bar, respectively. These intense conditions last for nanoseconds in an otherwise cool liquid. Under suitable conditions, broad band, picosecond flashes of light are generated, known as multiple bubble sonoluminescence (MBSL). This light can be used for on-line, reagentless, quantitative process analysis. Certain emitting species can be identified and quantitated directly from their MBSL spectra. Information about other species may be inferred from time-intensity profiles of MBSL from the bulk solution. Controlling the physical parameters is extremely important, as bubble dynamics are also sensitive to changes in external properties such as temperature, gas content, and system acoustics. Data from alcohol, alkali and alkaline salts systems will be presented.

66. THERMAL MODULATION OF MICROCALORIMETRIC SENSORS FOR CHEMICAL ANALYSIS. M. Benton Free, Robert E. Synovec, and Lloyd W. Burgess*, Center for Process Analytical Chemistry, Department of Chemistry, Box 351700, University of Washington, Seattle, WA 98195-1700.

The thermal modulation technique utilizes thermal pulses to perturb a system slightly from equilibrium, while measuring how physical parameters of the system change over the life and subsequent decay of the pulse. The current manifestation of the technique uses off-the-shelf silicon micromachined pressure and flow sensors in a thermal pulse/thermal measurement mode, although the technique is applicable to a variety of measurement systems, e.g. thermal/optical or thermal/acoustic. Promoting a zero-order sensor to first-order using thermal modulation provides quantitative information on mixtures based on the difference in boiling points, latent heats, and sorption/desorption interactions between the analytes and the sensor surface. The chemical information is extracted from the temporal response of the sensor using multivariate analysis. Thermal modulation has been applied to deconvolute the concentrations of binary gas phase mixtures ranging from 1 to 150 ppt. It has also been used to provide near real-time, on-column monitoring of a batch distillation.

67. CHEMOMETRICS FOR BIOPHARMACEUTICAL ANALYSIS. Cliona M. Fleming* and Bruce R. Kowalski, Center for Process Analytical Chemistry, Department of Chemistry, Box 351700, University of Washington, Seattle, WA 98195-1700.

As the biotechnology industry continues to grow, there is an increasing demand for data analysis tools that will simplify the extraction of information from complex data. LC/MS is an example of an instrument that produces such data. A data processing method for LC/ESI-MS data that effectively discriminates between analyte signal and random noise has been developed. The "windowed mass selection method" (WMSM) is based on a priori knowledge of LC/MS data: as an analyte elutes, its multiply-charged ions should have a constant signal, while ions that are not part of the analyte mass spectrum should not. Unlike a boxcar moving average that will simply smooth the data, this technique actually removes random noise. This method takes advantage of the 2-dimensional structure of the data. While this method is demonstrated for biopharmaceutical data, it is also applicable to all LC/ESI-MS data, in addition to CE/MS data.

68. THE INTERMEDIACY OF STREPTOLIDINE AND CAPREOMYCIDINE IN THE BIOSYNTHESIS OF STREPTOTHRICIN F BY STREPTOMYCES L-1689-23. Michael D. Jackson1, Nuria Tamayo1, Steven J. Gould1,3, and T. Mark Zabriskie2*, 1Department of Chemistry and 2College of Pharmacy, Oregon State University, Corvallis, OR 97331, 3Merck Research Laboratories-Basic Research, Rahway, NJ 07065.

Streptothricin F (STF) is representative of the peptidyl-nucleoside family of broad-spectrum antibiotics produced by Streptomyces species. In our continuing investigation on the biosynthesis of the streptolidine portion of STF, [6-13C]streptolidine has been synthesized and introduced to production flasks containing Streptomyces L-1689-23. Isolated STF was analyzed by 13C NMR to determine the extent of incorporation of labeled streptolidine. Results showed a 1% enrichment in the resonance corresponding to the guanidino carbon of STF further supporting a convergent biosynthesis of the antibiotic. A synthesis of L-capreomycidine, a proposed precursor to streptolidine, was developed that allowed the introduction of a 13C label at the guanidino carbon. This presentation will discuss these results as well as results from [7-13C]capreomycidine incorporation studies.

69. MODIFICATION OF ARCHAEAL tRNA: CLONING, OVER-EXPRESSION AND CHARACTERIZATION OF tRNA-GUANINE TRANSGLYCOSYLASE FROM METHANOCOCCUS JANNASCHII. Ying Bai, David Fox, Judy Lacy, and Dirk Iwata-Reuyl*, Department of Chemistry, Portland State University, Portland, OR 97207.

Two structural variants of the hypermodified nucleoside 7-deazaguanosine have been identified in tRNA, queuosine, which is found at position 34 of the anticodon in bacterial and eukaryotic tRNAs, and archaeosine, which is found at position 15 of the D-loop in archae. The enzyme tRNA-guanine transglycosylase (Tgt) catalyzes a key post-transcriptional base replacement reaction in the biosynthesis of queuosine. From homology searching of the Methanoccocus jannaschii genome with E. coli Tgt, a putative archaeal tgt gene was identified and cloned. The tgt gene was over-expressed in an E. coli expression system, and the recombinant Tgt enzyme was purified. Reported here is characterization of the recombinant enzyme, including tRNA and base specificity, thermal and pH activity profiles, and steady-state kinetic analysis.

70. CHARACTERIZATION OF RECOMBINANT 1-DEOXY-D-XYLULOSE 5-PHOSPHATE ISOMEROREDUCTASE, AN ENZYME IN THE NON-MEVALONATE PATHWAY TO ISOPRENOIDS. Philip J. Proteau* , Youn-Hi Woo, and Chanokporn Phaosiri, College of Pharmacy, Oregon State University, Corvallis, OR 97331-3507.

The non-mevalonate pathway to isoprenoids is an alternate biosynthetic route to isopentenyl diphosphate (IPP) that does not involve mevalonate as an intermediate. The initial linear five-carbon precursor in the non-mevalonate pathway, 1-deoxy-D-xylulose 5-phosphate (DXP) is converted to the branched 2-C-methyl-D-erythritol 4-phosphate by DXP isomeroreductase. The enzymatic steps involved are an isomerization followed by a NADPH-mediated reduction. We have cloned the gene from the cyanobacterium Synechocystis sp. PCC6803 into E. coli and overproduced the enzyme. Efforts to purify and characterize this enzyme will be presented.

71. OLIGOSACCHARIDE SYNTHESIS BY MUTANT GLYCOSIDASES: GLYCOSYNTHASES. David L. Jakeman*, Christoph H. Mayer, Harry Brumer, Laurent Gal, J. Anthony R. Warren, and Stephen G. Withers, Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 161.

Glycosynthases are a new and exciting class of functional enzymes which synthesize oligosaccharides from readily accessible activated donor and acceptor sugars.[J. Am. Chem. Soc., 1998, 120, 5583] Chemical synthesis of oligosaccharides is non-trivial and, whilst transferase enzymes readily synthesize oligosaccharides in vivo, in vitro their utility is limited for two reasons, poor enzyme availability and high cost of uridine diphosphate (UDP)-sugars. The advent of Glycosynthase enzymes (developed through mechanism guided evolution) allow the use of readily prepared a-fluoride sugars as activated donors onto the oligosaccharide chain. We shall present research directed towards broadening the range of acceptor and donor sugars employed as substrates for glycosynthases and to increase the diversity and specificity of the glycosidic linkages synthesised.

72. EFFECT OF CAROTENOID BIOSYNTHESIS INHIBITION ON PRODUCTION OF TAXANES. Jon E. Reitzenstein and Angela M. Hoffman*, Department of Chemistry, University of Portland, Portland, Oregon 97203.

Paclitaxel (Taxol), a taxane diterpene from yew trees has been approved by the FDA for treatment of ovarian (1992) and breast (1994) cancer. It is an effective inhibitor of cell division by interfering with cellular microtubules. The demand for paclitaxel is on the rise as the uses for this drug are increasing. This study investigates a technique with potential for increasing the amount of paclitaxel synthesized by yew cuttings and recovered in the laboratory. Norflurazon, a carotenoid biosynthesis inhibitor, was added to liquid in which cuttings from Taxus media x hicksii were incubated. Intermediate concentrations of Norflurazon enhanced the amount of paclitaxel and other taxanes recovered from the incubation liquid. The recovery of paclitaxel from the incubation liquid is compared with its recovery from incubated plant material.

73. PACLITAXEL AND OTHER TAXANES FROM HAZELNUT CELLS AND FUNGAL ISOLATES. Angela M. Hoffman*, Harnik Gulati, Waseem Khan, Maggie Ross, and Vickashni Sundar, Departments of Chemistry and Physics, University of Portland, Portland, OR 97203.

Paclitaxel (Taxol), an anticancer drug, and several related diterpenoid taxanes were originally isolated from the Pacific yew. Recently, we have also isolated these compounds from branches of several hazelnut (Corylus) cultivars. Taxanes have been isolated from fungi associated with yew, so it was not certain whether the hazelnut tissues or a fungus associated with them were the source of the taxanes. Nineteen fungal isolates were obtained from hazelnut bark or leaves. Paclitaxel could be recovered from at least six of these fungi. We have also found paclitaxel in sterile cells cultured from hazelnut. Results from both fungal isolates and cell cultures have been verified by LC/mass spectroscopy. This is the first verified isolation of paclitaxel from angiosperm tissues. Financial support from the University of Portland and the Oregon Hazelnut Commission are gratefully acknowledged.

74. PEROXYNITRITE-MEDIATED OXIDATION OF EPINEPHRINE AND 6-NITRO-EPINEPHRINE. Bryant A. Gilbert*1, Scott Winner1, Ranganayakulu Kurupatti1, Dagmar Bartos2, Donald D. Trunkey2, and Matthew Slater2, 1Department of Chemistry, Portland State University, Portland, OR 97207 and 2Department of Surgery, Oregon Health Science University, Portland, OR 97201.

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Epinephrine (1) and 6-nitroepinepherine (2) react with sodium peroxynitrite to yield adrenochrome (3) in 65 and 85% yield. The ONOOH mediated oxidation of 2 generates a very reactive 6-nitroquinone, which undergoes rapid intramolecular cyclization, followed by elimination of nitrite, to provide the oxidized product 3. The conversion of 1 and 2 to 3 via ONOOH mediated oxidation can represent a novel biological pathway for the regulation-degradation of epinephrine and its 6-nitro derivative.

75. ISOLATION OF EPINEPHRINE AND ITS OXIDATION PRODUCTS FROM HUMAN PLASMA AND URINE. Scott Winner1, Ranganayakulu Kurupatti1, Matthew Slater2, Dagmar Bartos2, Donald D. Trunkey2, and Bryant A. Gilbert*1., 1Department of Chemistry, Portland State University, Portland, OR 97207 and 2Department of Surgery, Oregon Health Science University, Portland, OR 97201.

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A two step procedure has been developed for the isolation of epinephrine (1) and its oxidation products adrenochrome (2) and adrenolutine (3) from human plasma and urine. The method involves the isolation 3 by boric acid gel trapping of 1 and 2. Acidic release of 1 and 2, followed by HPLC separation provides a fast and efficient procedure for the isolation of epinephrine and its oxidation products. Stability studies on 2 have provided time restraints for the entire procedure. In order to retain 95% of the adrenochrome in the original blood sample, the entire method must be completed within 30 minutes.

76. RADICAL CAGE EFFECTS IN THE PHOTODEGRADATION OF POLYMERS. David R. Tyler*, Dale A. Braden, Eileen E. Parrack, and Jonathan L. Male, Department of Chemistry, University of Oregon, Eugene, OR 97403-1253.

This study explored the origins of the observation that the quantum yields for polymer photodegradation depend on the polymer chain length. The (CpCH2CH2OSiR3)2Mo2(CO)6 (R = Me, i-Pr, n-Pr, n-Hx) and (CpCH2CH2NHC(O)(CH2)nCH3)2Mo2(CO)6 (n = 3, 8, 13, 18) complexes were synthesized and used as model complexes for the study. Irradiation of these molecules cleaves the metal-metal bonds and forms radicals via the intermediate formation of a radical cage pair. In the case of the silylated molecules, the quantum yields for the overall reaction with a radical trap decreased as the alkyl chain length increased. The quantum yield dependence on chain length was found to arise from changes in the cage effect. The cage effect was proportional to m1/2r2, where m is the mass of the radical and r is the radius. For the (CpCH2CH2NHC(O)(CH2)nCH3)2Mo2(CO)6 molecules, an in-cage trapping reaction occurred. This reaction is independent of chain length and therefore the quantum yields and cage effects were all identical. The effect of the solvent on the cage effect will also be discussed

77. DENSITY FUNCTIONAL THEORY CALCULATIONS ON 19-ELECTRON ORGANOMETALLIC COMPLEXES: MOLECULAR STRUCTURES AND MAGNETIC PROPERTIES. Dale A. Braden and David R. Tyler*, Department of Chemistry, University of Oregon, Eugene, OR 97403-1253.

Density functional theory (DFT) was used to calculate the molecular and electronic structures of a number of organometallic complexes that have a formal count of 19 electrons in the valence shells of the metal atom. The goals of these studies are: 1) to determine whether any structural distortions take place due to the presence of the extra electron; 2) to see if DFT can reproduce experimentally measured properties (electron-nuclear hyperfine coupling constants and Mossbauer quadrupolar coupling constants); 3) to see if the unpaired electron is localized on the metal or on a ligand; 4) when the existence of a particular 19-electron complex is uncertain, to calculate whether it is stable with respect to dissociation. We found that, in most cases, structural distortion is negligible, that DFT is capable of accurately reproducing experimental measurements, and that the unpaired electron is delocalized over the entire molecule.

78. O-ATOM TRANSFER FROM EPOXIDES TO Re(V) COMPLEXES. Kevin P. Gable, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

Rhenium complexes such as {(Cp*ReO)2(µ-O)2} are efficient O-atom acceptors from O2, sulfoxides and epoxides. The stoichiometric reaction of epoxides is stereospecific and high-yielding; the rate law is consistent with a mechanism involving preequilibrium scission of the dimer and rate-limiting O atom transfer from the epoxide to Cp*ReO2. Catalytic deoxygenation of epoxides using PPh3 is hampered by an unusual clustering process that siphons rhenium out of the catalytic cycle. Approaches to improved catalysis and elucidation of the mechanism of O-atom transfer are discussed.

79. SYNTHESIS AND REACTIVITY OF (Tp'ReO)2(µ-O)2. Eric C. Brown and Kevin P. Gable*, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

The reduction of trioxo half-sandwich Re(VII) complexes with triphenylphosphine has resulted in the formation of various oxo-bridged dimers. Although many examples of these systems have been explored, a limited amount of data is known for the dimeric rhenium(V) complex containing the hydrido-tris-(3,5-dimethylpyrazolyl)borate ligand (Tp' ligand). Recent efforts in isolating the dimeric (Tp'ReO)2(µ-O)2 (2) and its reactivity as a deoxygenation catalyst will be discussed.

80. REDUCTIVE COUPLING OF FULVENES, AN EFFICIENT METHOD FOR THE PREPARATION OF C2-SYMMETRIC ANSA-CHROMOCENE COMPLEXES. Gilbert J. Matare, Chemistry Department, University of Idaho, Moscow, ID 83844.

We have developed a high yield synthetic route to ansa-chromocenes via reductive coupling of functionalized fulvenes with activated calcium. 6,6-Dimethylfulvene, 6-phenylfulvene, 3,4-dimethoxyphenylfulvene, 6,6-diphenylfulvene, 6,6-methylphenylfulvene and 1-E-benzylidene-4,7-dimethylindene reductively couple with activated calcium to afford the corresponding ansa-calcocenes in yields of 80% or higher. We have crystallographically characterized cis and trans isomers of Ph2C2H2(h5-C5H4)2Ca(THF)2, trans-Ph2Me2C2(h5-C5H4)2Ca(THF)2 and trans-Ph2C2H2(h5-4,7-Me2C9H4)2Ca(THF)2. Transmetalation of the ansa-calcocenes with CrCl2 in the presence of Lewis bases such as CO, t-BuNC and CH3NC have been performed and will be discussed. We have recently been able to grow single crystals of ((CH3O)2Ph)2C2H2(h5-C5H4)2CrCO suitable for an X-ray analysis. Reactions of Ph2C2H2(h5-C5H4)2Ca(THF)2, with CrCl3 and CrBr3 affords the corresponding ansa-chromocene halides. The ansa-chromocene halides can be reduced to Cr(II) by magnesium powder in the presence of carbon monoxide. Work on substituting the halide ligands with other reactive hydrocarbyl ligands will also be discussed.

81. CHEMISTRY OF ELECTRON-DEFICIENT BENZOHETEROCYCLE COMPLEXES OF TRIOSMIUM CLUSTERS. Md Joynal Abedin, Edward Rosenberg*, and Kenneth I. Hardcastle, Departments of Chemistry, The University of Montana, Missoula, MT 59812 and California State University, Northridge, CA 91330.

We recently reported the synthesis and reactivity of electron deficient triosmium complexes of quinoline where the electron deficiency at the metal core is transmitted to the 5-position of the quinoline ring activating it towards nucleophilic addition reactions and thus reversing the normal reactivity of the quinoline ring system (i.e., nucleophilic attack at the 2 or 4 position of the heterocyclic ring).1 We have now extended this chemistry to a broad range of heterocycles including 5,6 benzoquinoline, phenanthridine, quinoxaline, benzothiazole, benzoxazole, benzotriazole, and 2-substituted benzimidazoles. The synthesis and structure of these benzheterocycle complexes will be discussed along with the effect of ring substituents on the course of the reactions. Preliminary results on the reactivity of these complexes with nucleophiles, two electron donor ligands and protic acids will also be presented.
1. E. Rosenberg, B. Bergman, K. I. Hardcastle, M. Visi, J. Ciurash, J. Amer. Chem. Soc. 1998, 120, 12818.

82. CURRENT STATUS OF MOPAC 2000. James J. P. Stewart, Stewart Computational Chemistry, 15210 Paddington Circle, Colorado Springs, CO 80921.

The semiempirical program MOPAC has evolved steadily over the past 15 years. While the original code was limited to calculations of the ground state of simple gas phase molecules, the current program is very versatile, and can model a wide range of systems. In this presentation, a description of some of the new features of MOPAC 2000 will be presented. These include:
* The program: dynamic memory allocation, multiprocessor capability, range of platforms supported, program structure
* Methods: AM1-d, MNDO-d, intersystem crossing, and solvation models
* Applications: electronic phenomena in the solid state
* Linear Scaling: enzymes and other macromolecules
* A much expanded manual to help users understand the program.
However, MOPAC should not be regarded as a finished product, rather it should be viewed as a work in progress. Examples of features that need to be improved are:
* According to theory, the solid state methods can be made more efficient.
* Some optical frequency transition intensities are underestimated.
* Non-linear optics calculations need to be extended to exotic systems.
* Some solvation models are still not sufficiently versatile.
* The accuracy of the methods in MOPAC needs to be increased.
The time scale for addressing limitations will be outlined.

83. VISUALIZATION OF CHEMICAL REACTIVITY. Sam Cole, Oxford Molecular Group, 14940 N.W. Greenbrier Parkway, Beaverton, OR 97006-5733.

Many aspects of chemical reactivity can be explored using quantum mechanical methods. We present examples that focus on the visualization of computed partial charges, frontier densities, electrostatic potentials, and frontier molecular orbitals to gain insight into chemical reactivity. MNDO methods (MOPAC) are used to calculate approximate transition-state geometries and to verify that the transition state connects to the expected reactants and products.

84. PREDICTING ATMOSPHERIC DECOMPOSITION LIFETIMES. Peter Herman, Oxford Molecular Group, 14940 NW Greenbrier Parkway, Beaverton, OR 97006-5733.

A chemical compound's environmental decomposition lifetime can be as important a property as the desirable property(s) for which it was synthesized. The ability to estimate this property prior to synthesis can save resources by screening out candidate compounds which might perform the desired function, but be too damaging to the environment. Within the last decade it has been shown that for many organic compounds the calculated HOMO energy correlates closely with the log of the molecule's rate constant for gas-phase reaction with hydroxyl radical, chief initiator of oxidation in the lower atmosphere. This offers a method to predict the atmospheric decomposition lifetime of compounds which have been designed but not yet synthesized. The well-studied example of CFC-replacement candidates will be discussed in terms both of the model's predictive usefulness, and a possible mechanistic explanation for the observed correlation.

85. CHARACTERIZATION OF ELECTROLYTES BY COMPUTER MODELING. Richard V. Whiteley, Jr., James O. Currie, Jr.*, and Kevin E. Johnson, Chemistry Department, Pacific University, Forest Grove, OR 97116.

The high voltage of the modern lithium ion battery requires an electrolyte of exceptional stability. The most successful systems use organic esters and di-esters as the electrolyte solvent. These solvents typically undergo an irreversible reduction at the lithium electrode when the battery is first charged, and this permanently diminishes the capacity of the cell. Strategies have been developed to model the reductive decomposition of the most common solvent, ethylene carbonate, and some of its more interesting analogs. The expectation is that the performance of solvents never before tested might be predicted from the model. The important issues and considerations required for a workable model are presented along with reaction pathways that are predicted by this model.

86. DFT CALCULATIONS ON Pt(CN)2(CO)2 MONOMER AND DIMER. Monia E. Hilliard, Ronald D. Poshusta,* and Glenn A. Crosby, Department of Chemistry, Washington State University, Pullman, WA 99164-4630.

Emission spectra of square planar complexes of Pt(II) are consistent with either metal-ligand charge transfer or pp* excimer models. To help resolve the uncertainty in the nature of electronic excitation in Pt(II) complexes, ab initio calculations were performed. The Pt(CN)2(CO)2 complex was chosen for the investigation as a system with enough complexity to represent typical Pt(II) complexes, and yet simple enough to be susceptible to accurate computations. A dimer of this compound was chosen as a first approximation of the structure in the crystal. A series of optimizations of both the monomer and dimer were completed employing B3LYP density functional theory and stable states were found and confirmed by vibrational frequency calculations. The stacking pattern of the molecules, the shear between the molecules and the Pt-Pt distance obtained for the dimer match fairly well those found for the halogen analog Pt(CO)2Cl2 through x-ray crystallography. Results of population analyses and DFT-based excitation calculations will also be reported.

87. MOLECULAR MODELING OF HYDROGEN ABSTRACTION AND SUBSEQUENT RADICAL RECOMBINATION REACTIONS BY TRIPLET BENZOPHENONE. Douglas A. Preston, Gwen P. Shusterman, and Bryant A. Gilbert*, Department of Chemistry, Portland State University, Portland, OR 97207-0751.

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Tethered benzophenones have recently garnered interest as photoaffinity labels for biological systems. Typically, the yields of these photo-labeling experiments are below 5%. High-level Density Functional Theory and ab initio calculations were performed to determine the geometry and energy associated with the hydrogen abstraction and radical recombination reactions. Application of this information towards the development of more efficient photoaffinity labels will be discussed.

88. DENSITY FUNCTIONAL THEORY AND EXPERIMENTAL EVALUATION OF OXIDATION POTENTIALS OF SUBSTITUTED CATECHOLS. John Cramer and Bryant A. Gilbert*, Department of Chemistry, Portland State University, Portland, OR 97207-0751.

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High-level Density Functional Theory calculations were performed to determine the oxidation potentials of substituted catechols. The following isodesmic reaction scheme was employed to reduce systematic errors present in the calculations. A negative DG for the reaction indicates the substituted catechol would be more stable to oxidation than the parent catechol. Experimentally determined oxidation potentials of the catechols validated the theoretical method.

89. CONTROLLED FIELD EXPERIMENTS: A UNIQUE METHOD TO STUDY THE FUNDAMENTAL PROCESSES CONTROLLING THE GAS-PARTICLE PARTITIONING BEHAVIOR OF SEMIVOLATILE ORGANIC COMPOUNDS (SOCS). Brian T. Mader and James F. Pankow*, Department of Environmental Science and Engineering, Oregon Graduate Institute, Portland, OR 97291-1000.

The term semi-volatile organic compound (SOC) refers to compounds having vapor pressures between 10-11 and 10-4 atm. Many compounds of environmental interest are considered SOCs, examples are: the polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organic pesticides and aromatic organic compounds comprising secondary organic aerosols present in urban smog. Controlled field experiments (CFEs) consist of equilibrating ambient aerosols with SOCs generated in the gas phase using ambient air which has been maintained at a specific temperature and relative humidity to prevent their diurnal cycling. Such experiments reduce sampling artifacts which confound the accurate measurement of the gas-particle partition coefficients (Kps) of SOCs using conventional high-volume air sampling. Aerosol organic matter normalized gas-particle partition coefficients (Kp,om) for the partitioning of the PCDDs, PCDFs and PAHs to ambient Portland and Denver aerosols measured using CFEs will be presented. Initial data suggests it may be possible to predict the gas/particle partitioning behavior of the PCDD/Fs and PAHs at any urban location using linear free energy relationships (LFER) determined in this study, compound pure subcooled liquid vapor pressure and aerosol organic matter content.

90. DETERMINATION OF A WIDE RANGE OF VOLATILE ORGANIC COMPOUNDS IN WATER USING PURGING/ADSORPTION/THERMAL DESORPTION AND GAS CHROMATOGRAPHY/MASS SPECTROMETRY. Wentai Luo, Jay S. Hollingsworth, Lorne M. Isabelle, and James F. Pankow*, Department of Environmental Science and Engineering, Oregon Graduate Institute, Portland, OR 97291-1000.

A purge and trap method was developed for the determination of 90 volatile organic compounds (VOCs) in water. Water samples were heated and purged at 85°C and trapped with multisorbent adsorption/thermal desorption (ATD) air sampling cartridges. The ATD cartridges were thermally desorbed and analyzed by GC/MS. The VOCs are halogenated alkanes, halogenated alkenes, ethers, alcohols, nitriles, esters, ketones, aromatics, a disulfide, and a furan. This group includes compounds such as tert-butyl alcohol and tert-amyl alcohol can not be measured by currently available purge and trap methods at low levels. The volatility of the target VOCs from water range from that of dichlorofluoromethane (CHFCl2) down to that of alcohols. The method detection limit (MDL) values range from 0.01 ppb (mg/L) to 0.5 ppb for a 5 mL sample.

91. ASSESSING THE ENVIRONMENTAL FATE OF METHYL TERT-BUTYL ETHER. Clinton D. Church, James F. Pankow and Paul G. Tratnyek*, Department of Environmental Science and Technology, Oregon Graduate Institute of Science and Technology, Portland, OR 97291-1000.

The concern over contamination of groundwater by methyl tert-butyl ether (MTBE) has increased the need for a better understanding of the processes that control its environmental fate. As part of a study to characterize the kinetics and mechanisms of MTBE degradation, we developed a direct aqueous injection (DAI) GC/MS technique that allows us to simultaneously analyze for MTBE and its expected degradation products at the sub-ppb level. We used the method to explore the abiotic hydrolysis of tert-butyl formate (TBF, a major product of MTBE photooxidation) to tert-butyl alcohol (TBA). We found that TBF is subject to rapid neutral and acid/base catalyzed hydrolysis with half-lives at 22°C of approximately 5 days, 8 hours, and 8 minutes, respectively. When the method was applied to effluent from aerobically fed column microcosms prepared with aseptic core materials from three pristine sites, conversion of MTBE to TBA was observed after a lag period of approximately 35 days, but no evidence of TBA degradation was observed. In similar columns with anaerobic feeds or with BTEX (gasoline constituents- benzene, toluene, ethyl-benzene, and o-, m-, and p-xylenes) contaminated aerobic feeds, however, we have not seen any evidence of MTBE degradation up to 120 days. We have also used the method to analyze groundwater samples from a number of sites, representing a wide range of aquifer conditions. To date, these samples have not produced unequivocal evidence of MTBE degradation. The combined results presented here suggest that microbial degradation of MTBE may occur to a limited extent under aerobic conditions. This degradation is unlikely to be a rapid or widespread process in the subsurface environment, however, even though appreciable conversion is readily achieved under controlled conditions in the laboratory.

92. EVALUATING THE EFFECT OF IN-SITU AIR SPARGING ON AQUEOUS MTBE CONCENTRATIONS. Illa L. Amerson-Treat* and Richard. L. Johnson, Department of Environmental Science and Engineering, Oregon Graduate Institute, Portland, OR 97291-1000.

In-situ air sparging (IAS) is a remediation technology commonly used for gasoline contamination. The premise is that the injected air will remove volatile organic compounds (VOCs) by volatilization and enhance aerobic biodegradation processes. In general, IAS effectiveness is limited to zones where the contaminant and injected air are in close contact. Because of this, some rebounding of contaminant concentrations is typically seen following system shutdown. This rebounding may pose a significant problem with respect to MTBE. Gasoline may contain >10% MTBE by volume. Due to its high solubility, MTBE remaining in any residual non-aqueous phase gasoline not removed by IAS will dissolve quickly and may result in elevated aqueous concentrations once again. A large 3-dimensional physical model is being used to simulate the conditions of a gasoline spill and resulting contaminant plume. The physical model allows extensive plume characterization and monitoring which is not typically feasible at gasoline release sites. This paper will present the results of the quasi-field scale experiment and discuss whether or not IAS has the potential to permanently reduce aqueous MTBE concentrations.

93. HYDROLYTIC TRANSFORMATION OF TKEBS BY SUBSURFACE SOLIDS FROM A CONTAMINATED SITE. M. Chu and L. Semprini*, Department of Civil, Construction, and Environmental Engineering, Oregon State University, Corvallis, OR 97330.

Tetrakis(2-ethylbutanoxy)silane (TKEBS) is present along with trichloroethene (TCE) as a subsurface contaminants at Site 300, Lawrence Livermore National Laboratory (LLNL), CA. The anaerobic transformation of TCE is driven by the fermentation of a hydrolytic product of TKEBS, 2-ethylbutanol. Therefore, the understanding of the hydrolytic degradation of TKEBS under site conditions will help in the understanding of transformation processes occurring at the site. This study investigated the abiotic hydrolytic transformation of TKEBS at different initial water contents and different particle sizes with soil from the site. The rates and products of TKEBS transformation in batch kinetic tests were determined by dichloromethane extraction and gas chromatography. The results showed that all particle sizes had catalytic ability to accelerate the hydrolysis of TKEBS. However, smaller particles consisting of silt and clay did not show greater ability to enhance TKEBS transformation. Studies are currently being performed to evaluate the effect of soil water content on TKEBS transformation

94. PILOT SCALE DEMONSTRATION OF A SURFACTANT MODIFIED ZEOLITE PERMEABLE BARRIER. Timothy L. Johnson* and Richard L. Johnson, Oregon Graduate Institute, Portland, OR 97291.

Permeable barriers are gaining acceptance as a means to remediate shallow groundwater contamination plumes. Mixed waste plumes, consisting of organic and inorganic contaminants, are especially difficult to remediate due to the varying chemical properties of the constituents. Surfactant-modified zeolite has been shown to sorb and retard inorganic oxyanions, heavy metal cations, and a broad range of organic contaminants. Zeolites are naturally occurring aluminosilicates with open, cage-like structures and high internal and external exchange capacities. Surfactant modification of zeolite constitutes replacing base cations on the external exchange sites of unaltered zeolite with a cationic surfactant. A pilot-scale demonstration was conducted at the OGI Large Experimental Aquifer Program to test the use of surfactant modified zeolite as a permeable barrier material for remediation of PCE and Cr. The LEAP site at OGI is designed to facilitate large-scale transport experiments by offering controllable aquifer flow regimes, a high-density sample acquisition network, and onsite data analysis, while maintaining a safe and containable contaminant delivery system.

95. HIGH EFFICIENCY ENVIRONMENTAL SORBENT MATERIALS: SELF-ASSEMBLED MONOLAYERS ON MESOPOROUS SUPPORTS (SAMMS) FOR METAL REMOVAL FROM AQUEOUS SYSTEMS. Glen E. Fryxell*, Jun Liu, Teresa A. Hauser, Zimin Nie, Richard T. Hallen, Mauxu Qian, and Kim F. Ferris, Pacific Northwest National Laboratories, Richland, WA 99352.

Mesoporous silica (MCM-41) was effectively functionalized with a self-assembled monolayer composed of ethylenediamine terminated silanes. The details of the optimized derivatization will be presented. These aminated mesoporous supports were then tested for their binding affinities with a variety of transition metal cations of environmental concern (Cu, Co, Ni, Cd, Pb, etc.). Details on loading capacity, distribution coefficients, and characterization will be summarized.

96. GROUND WATER STUDIES IN TOPPENISH WASHINGTON. Hossein R. Divanfard*, Herman Moya, and Ron Sell, Heritage College, Toppenish, WA 98934.

In 1998 a project conducted at Heritage College monitored the concentration of combined nitrate-nitrite and the pesticides atrazine and diazinon in drinking water wells in the Toppenish Basin. Water samples were collected and analyzed on a weekly basis. The results showed that the combined nitrate and nitrite concentrations remained relatively constant throughout the irrigation period at all of the sites. At the two wells in the vicinity of Harrah, WA, however, the combined nitrate and nitrite exceeded regulator standards brought forth in the Safe Drinking Water Act of 1972. Based on previous work by the USGS in 1979 and 1989, the concentration of combined nitrite and nitrates has increased 176%, in one case, over a period of 19 years. The pesticides were not detected in any of the wells. This project was student oriented. Eight undergraduate students were involved in QA-QC development, training, site selection, sampling, analysis and report writing.

97. DETECTING THE GEOGRAPHIC ORIGIN OF FOODS. Kim A. Anderson1* and Brian W. Smith2, 1Department of Food Science and Toxicology, Analytical Sciences Laboratory, Holm Research Center, University of Idaho, Moscow, ID 83844-2201. 2Department of Pure and Applied Mathematics, Washington State University, Pullman, WA 99164.

The determination of geographic origin of raw commodities and food products through chemical analysis is timely. Economic incentives continue to drive some retailers to mis-identify geographic origin of raw commodities and food products. The determination of geographic origin is important for both enforcement options for the food industry and protection of the consumer from overpayment and deception. Mis-identifying geographic origin of raw commodities and food products is a concern for growers and consumers and includes issues of quality, safety and consumer's preferences. Using trace element analysis including Ba, Cd, Cr, Co, Cu, Fe, Mo, Mn, Ni, V, Zn, K, Mg, P, Pb, and Sr coupled with sophisticated data analysis; geographic origin of foods can be determined. Results for several foods will be presented, including apples and coffee. Demonstration of capability for determining geographic origin of apples from two growing regions will be presented. Apples from Washington (W) and New Zealand (Z) are compared using Canonical Discriminant Analysis (CDA). Trace element data for roasted coffees from eight different growing regions, including South/Central America, Africa and Indonesia will also be presented.

98. DEMONSTRATION OF MAGNETIC PROPERTIES OF FE, FERRIC ION, PERMANGANATE ION, AND MANGANESE DIOXIDE. David Ehrenkranz, Westview High School, 4200 NW 185th Ave., Portland, OR 97229.

Using two neodymium-boron-iron magnets, the magnetic properties of Fe, ferric ion, permanganate ion, and manganese dioxide will be demonstrated and correlated with their electronic structures and spin.

99. INTERMOLECULAR FORCES. Marcy Martone, Century High School, 2002 SW 234th Ave., Hillsboro, OR 97214.

Grade Level: Chemistry or Integrated Science.
Technology: CBL, Graphing Calculator (CHEMBIO program), temperature probes
Materials: isopropyl alcohol and distilled water
Why do we perspire? A chemical demonstration showing the rate of evaporation of water and isopropyl alcohol. Students will look at cooling curves to begin discussion of hydrogen bonding and dipoles. Additional demo will be provided if technology is not available to teachers.

100. ALTERING REACTION RATES. Arnie Ariss, Hillsboro High School, 3285 SE Rood Bridge Road, Hillsboro, OR 97213.

A demonstration to show one of the factors affecting the rate of reaction, using equipment that you may already have in your stockroom. Simple homemade equipment will shown that will easily accomplished the desired reaction. Then using the apparatus (paint can w/ attachments), a watch glass, flame source(candle), and powdered starch, the rate demonstration will be conducted.

101. THE ORANGE CLOCK REDOX DEMONSTRATION: WHO IS ACCEPTING ELECTRONS AT THE CATHODE? Katy Olsen and Todd P. Silverstein*, Chemistry Department, Willamette University, Salem, OR 97301.

A common electrochemistry demonstration produces electrical current from fruit juices and other foods and beverages. Typically, strips of copper and zinc (or magnesium) are placed in a fruit or beverage and connected to the battery terminals of a clock. The voltage and current produced by oxidation of the zinc (or magnesium) are sufficient to run the clock for several days. There has been however some debate as to the nature of the cathode half reaction: Some suggest that either hydrogen ions or water are reduced at the cathode. If this is true, voltage should decrease by about 60 mV per pH unit, according to the Nernst equation. In this project we measured the voltage across copper/magnesium and copper/zinc strips in different solutions and beverages, buffered at various pH's. Under certain conditions we did observe the expected -60mV/pH unit slope, but under other conditions the deviation from Nernst theory was substantial. Deeper exploration of a seemingly simple electrochemistry class demonstration has led us to some surprising conclusions.

102. CATALYTIC DECOMPOSITION OF ACETONE. Dennis B. McKinney, Orcas Island High School, Eastsound, WA 98245.

This is an easy, safe way to demonstrate the function of a catalyst to your high school chemistry students. A heated copper penny is suspended above a container of acetone. When the heated penny is surrounded by a mixture of air (O2) and acetone vapor, catalysis occurs at the surface of the copper converting the mixture to water and carbon dioxide. This reaction is sufficiently exothermic to keep the penny hot and the process self sustaining.

103. STUDENT OBSERVATION OF SCIENCE "MYSTERY" CHEMICAL REACTION CALLED OLD FOAMY, ALSO CALLED ELEPHANT'S TOOTHPASTE. Lynn L. Mitchell, Chemistry Teacher, Hood River Valley High School, 2763 Montello, Hood River, OR 97031.

To enhance my classes I perform various experiments and have my students write about what they observe. This experiment involves placing 5.0 mL of dish soap in a 500 mL graduated cylinder along with 10.0 mL of 30 % sodium peroxide. Then add 10.0 mL of a 1.0 M solution of potassium iodide, stand back and let the reaction take place. Additional "mysteries" may be demonstrated if time permits. The idea for "Old Foamy" reaction came from Flynn Fax, distributed by Flynn Scientific Company.

104. THE LIQUID NITROGEN FOUNTAIN. Jeffrey A. Rahn*, Robin P. McRae, Timothy M. Beamer, and Norm LeBret, Department of Chemistry, Eastern Washington University, Cheney, WA 99004-2431.

Details of a demonstration using liquid nitrogen are presented. The demonstration is based on a 500-mL transparent polyethylene soft drink bottle with a screw-on pop-up drink top. Prior to the demonstration, a balloon is placed over the popped-up spout of the bottle top. The drink bottle is filled with liquid nitrogen and the top, with the balloon affixed, is quickly put in place and screwed on tight. As the liquid nitrogen in the bottle boils, the balloon inflates. When the balloon bursts the noise produced is far greater than would ordinarily be expected, and a fountain of liquid nitrogen and condensing water vapor shoots into the air above the bottle.

105. SOME FAVORITE DEMONSTRATIONS. Tom Dunne*, Chemistry Department, Reed College, Portland, OR 97202-8199.

A few simple, favorite demonstrations will be attempted. Related principles of chemistry will be indicated.

106. GRADUATE SCHOOL PREPARATION: SEMINAR AND PANEL DISCUSSION. Morton Z. Hoffman, Department of Chemistry, Boston University, Boston, MA 02215.

This seminar and discussion will cover everything you ever wanted to know about graduate school in the chemical sciences: how to get in, how to stay in, and how to get out (in a reasonable length of time). A
panel of graduate students will also discuss life in graduate school.

107. HIGHLY SELECTIVE STATIONARY PHASES FOR CAPILLARY HPLC AND CEC BASED ON MOLECULAR IMPRINTED POLYMERS. Patrick T. Vallano, Gabriela Chirica and Vincent T. Remcho*, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

Molecular imprinting is a technique in which specific recognition sites are formed in a polymer matrix by synthesizing the polymer in the presence of a template molecule. The resultant imprinted polymer, or MIP, is capable of selectively rebinding the template, even in the presence of structurally similar species. The high selectivity of the recognition process has rendered MIPs useful in several areas of analytical chemistry including sensors, immunoassays and separations. The focus of this work is the use of molecular imprinted polymers as highly selective stationary phases in capillary HPLC and CEC. The imprinted polymers employed in this study were synthesized in bulk, ground and sieved to yield particles with a nominal diameter of less than 30 mm. The MIP particles were then packed into fused silica capillaries using a slurry method. Baseline resolution of the template from a series of closely related structural analogs was obtained with MIPs prepared with nortriptyline, a tricyclic antidepressant drug, as the imprinted species. A separation of the same mixture was not possible on a reference capillary (i.e., polymer prepared under identical conditions in the absence of template).

108. HPLC COLUMN SWITCH METHOD TO QUANTITATE ENANTIOMERS IN HUMAN PLASMA. Jin Y. Huang, Daniel H. Marchand and John W. Dolan*, LC Resources Inc., 3138 NE Rivergate Bldg. 301C, McMinnville, OR 97128.

A HPLC column switching method to quantitate enantiomers in human plasma was developed. The method was intended to support studies determining if metabolic racemization is occurring. The sample preparation procedure consisted of manual solid phase extraction. The samples were analyzed by chiral HPLC with a column-switching method. This involved injecting the samples onto the primary column and then diverting the enantiomers onto the chiral column. This diversion occurred just prior to the elution of the enantiomers. The system was then returned to its original configuration, which allowed for the re-equilibration of the primary column. The system configuration was next changed to allow for detection of enantiomers as they eluted from the chiral column. Detection was by fluorescence. The ruggedness of the method was tested over a three-day period. The sensitivity limit of the assay was determined to be 0.003 mg/ml of enantiomer in human plasma.

109. GRADIENT HPLC BACKGROUND PEAKS - A CASE STUDY. Michael D. Nelson and John. W. Dolan*, LC Resources Inc., 3138 NE Rivergate, Bldg. 301C, McMinnville, OR 97128.

A problem that occurs in high performance liquid chromatography (HPLC) runs is the presence of spurious peaks in blank baselines during gradient runs. These peaks occur when no sample is injected, indicating the peaks must originate from the mobile phase buffers or from other system components. Peaks of about 0.05% of the area of the parent peak are of concern in pharmaceutical degradation studies. Such baseline peaks make difficult the task of determining which peaks are actually sample related, and which are due to the system. It was necessary to determine the source of these peaks and to try to eliminate them. It was suspected that the buffer manufacturer was not supplying clean phosphate. When several different brands were compared, peak profiles were similar, indicating that the peaks originated from the system, and not the buffer. There were several steps in the buffer preparation process that were suspected of causing contamination. These were glassware contact, microfiltration, pH adjustment, and degassing. Each of these was isolated and examined. Contact with glassware and pH adjustment were found to cause the majority of the contamination. Rinsing all glassware prior to use and external pH reading was sufficient to greatly improve spurious baseline peaks.

110. FRITLESS CAPILLARY COLUMNS BASED ON CONVENTIONAL HPLC PACKING MATERIALS. Gabriela S. Chirica, Patrick T. Vallano, and Vincent T. Remcho*, Department. of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

A principal driving force in the continued development of Capillary Electrokinetic Chromatography is to enhance its suitability for routine analytical work. This study addresses the issue of column fragility, proposing "entrapped" columns as an alternative to routine frit-retained packed beds. A solution of monomers is introduced into a capillary packed with a conventional HPLC sorbent and allowed to polymerize yielding a medium in which the packing material is stabilized and retained inside the capillary by the polymer matrix. Columns prepared using this technique are mechanically robust and can be cut to any desired length. These entrapped columns are suitable for both micro HPLC as well as CEC. The chromatographic performance of the initial packing material remains largely unaffected by the treatment. The entrapment matrix can be designed so as to introduce ionizable groups. This extends the range of materials that may be used as sorbents for CEC separations.

111. TEMPERATURE CONTROL IN HPLC. Robert G. Wolcott1 and John W. Dolan2*, 1Linfield College, Department of Chemistry, McMinnville, OR 97128 and 2LC Resources Inc., 3138 NE Rivergate, Bldg. 301C, McMinnville, OR 97128.

Control of temperature in high performance liquid chromatography (HPLC) operation is critical for achieving reliable, repeatable results. Two major problems must be overcome: (a) column temperature must be kept constant, and (b) temperature of incoming solvent must be constant and equal to that of the column. Consequences of poor temperature control include changes in retention time of 1-2% per °C, changes in separation selectivity for certain pairs of compounds, and reduction of column plate height. Problems in setting and stabilizing column and incoming solvent temperatures include variations related to location within an oven, temperature controller accuracy and sensitivity, and cost and performance of monitoring equipment. This poster compares use of active and passive preheating of incoming solvent, block heater and forced air ovens, and describes a "chemical thermometer" that can be used to estimate average column temperature independent of monitoring equipment and flow rate. Simple suggestions are offered for achieving a close match between temperatures of incoming solvent and column, and optimizing thermal factors that affect HPLC system performance.

112. BASELINE DEVIATIONS IN RP-HPLC WITH TRIFLUOROACETIC ACID - ACETONITRILE GRADIENTS. Nan S. Wilson and John W. Dolan*, LC Resources Inc., 3138 NE Rivergate, Bldg. 301C, McMinnville, OR 97128.

Trifluoroacetic acid-water-acetonitrile (TFA-ACN) reversed-phase high performance liquid chromatography (RP-HPLC) gradient methods are widely used for analysis of pharmaceutical and biological compounds. Blank baselines monitored at 225 nm show unusual negative dips as the gradient reaches 100% ACN. Nonlinearity of TFA-ACN baselines have been reported earlier, however, the observed post-gradient baseline dips were unexpected. This phenomenon is attributed to the nonlinear uptake of TFA by the stationary phase as the ionization of TFA abruptly changes near 100% ACN. The behavior is more pronounced with longer columns and/or less polar stationary phases. This problem is of minimal importance if gradients of >90% ACN/TFA are avoided when detection at 225 ±5 nm is used.

(Note - the poster previously listed as # 113 is now # 107)
113. CHARACTERIZATION OF SULFATED ZIRCONIA. Susmita Bose,* Yun You,** Anand Chellappa,** William Thomson,** and Yang Wang,*** *School of Mechanical and Materials Engineering, **Department of Chemical Engineering, Washington State University, Pullman, WA 99164 and Battelle Pacific Northwest National Laboratory, Richland, WA 99352.

Bulk catalysts consisting of sulfated zirconia (SZ), and iron and manganese promoted sulfated zirconia, as well as sulfated zirconia supported on mesopore silica, were prepared and investigated by different characterization techniques. Solid supported acid catalysts can replace concentrated acids to perform various acid catalyzed organic reactions. The surface acidic properties of various solid supported acid catalysts were evaluated by measuring adsorbed ammonia using temperature programmed desorption (TPD) method. Quantitative measurements of Lewis and Bronsted acidity on solid acid catalysts, in-situ, was measured using IR spectroscopic method. These measurements were then correlated for each catalyst with their catalytic activity for n-butane isomerization. The presentation will include various catalytic activity measurements of different catalysts with respect to their acidity.

114. DATABASE CHANGE CONTROL FOR TANK WASTE INFORMATION NETWORK SYSTEM INTERFACE. Rebecca A Bechtold,* Melvin R. Adams, and Kathleen M. Hall, Pacific Northwest National Laboratory, Richland, WA 99352.

The Tank Waste Information Network System [TWINS] is a publicly accessible web-based interface system for tank waste characterization information at the Hanford site. The TWINS provides a single convenient point-of-access for obtaining a growing quantity of tank data for Hanford's 177 Underground Storage tanks and miscellaneous tanks. The Hanford Tank Characterization Database currently contains in excess of 800K records, and management of the information requires constant attention to assure that the quality of information is of the highest caliber. This paper describes the current methodology for tracking and correcting data deficiencies through the change process. In addition, the computer has been programmed to identify certain common types of data deficiencies. As data problems are investigated and corrected, an independent software system is used for documenting and tracking the issue throughout its resolution.

115. DETERMINATION OF TRACE LEVELS OF Fe(II) AND TOTAL Fe IN NONREFRACTORY MINERALS USING 1,10-PHENANTHROLINE. Bryan K. Reichert1, Amy L. Fong1, J. Charles Templeton1, James E. Amonette2, 1Department of Chemistry, Whitman College, Walla Walla, WA 99362; 2Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352.

When our 1,10-phenanthroline method was used to quantify trace levels of Fe(II) and total Fe in nonrefractory minerals, errors associated with equilibration time, Fe content, and sample weighing were identified. For both Fe(II) and total-Fe measurements, equilibration times of 2 h after addition of color-promoting reagents (i.e., 1% citrate or 1% citrate/1% NH2OH) were needed to reach maximum absorbance. This period contrasts with immediate color development for Fe(II) determinations and a 90-minute period for total Fe when routine samples are analyzed. Greater uncertainty in sample weights was also observed when small sample sizes (<30 mg) of the primary standard [ferrous ethylenediammonium sulfate (FES)] were analyzed. This problem was resolved by diluting FES powder 10-fold in reagent-grade Na2SO4 to create a new standard for trace-level Fe analyses. With these procedural changes, analysis of trace levels of Fe can be achieved with the same accuracy and precision expected for routine samples.

116. STEREOCHEMICAL STUDIES OF 1-DEOXY-D-XYLULOSE-5-PHOSPHATE ISOMEROREDUCTASE, AN ENZYME IN THE NONMEVALONATE PATHWAY TO ISOPRENOIDS. Youn-Hi Woo, Chanokporn Phaosiri, and Philip J. Proteau*, College of Pharmacy, Oregon State University, Corvallis, OR 97331-3507.

The non-mevalonate pathway is an alternate biosynthetic route in some bacteria, algae and plants to isopentenyl diphosphate (IPP), which is the building block of isoprenoid metabolites. This recently described pathway proceeds via 1-deoxy-D-xylulose-5-phosphate (DXP), which is converted to 2-C-methyl-D-erythritol-4-phosphate by DXP isomeroreductase. The stereochemistry of the reduction step of this enzymatic conversion was investigated. The isomeroreductase gene (dxr) from the cyanobacterium, Synechocystis sp., was overexpressed in E. coli. The two necessary substrates to examine the stereochemistry, DXP and (3S)-1-deoxy-[3-2H]-D-xylulose-5-phosphate, were both chemically synthesized from propargyl alcohol in 9 steps with 11% overall yield. The unlabeled DXP will be incubated with the isomeroreductase in the presence of deuterated NADPH (NADPD) while the 3-2H-DXP will be treated with NADPH. The two monodeuterated 2-C-methyl-D-erythritol-4-phosphate products will be converted to the bisacetonides of 2-C-methylerythritol and analyzed using a combination of NOE and 2H NMR experiments.

117. MECHANISTIC STUDIES OF QueA, AN ENZYME INVOLVED IN THE HYPERMODIFICATION OF tRNA. Sylvia Daoud Kinzie, Bernd Thern, and Dirk Iwata-Reuyl*, Department of Chemistry, Portland State University, Portland, OR 97207.

Queuosine (Q) is a hypermodified base present in specific tRNAs (Asn, Asp, Tyr and His) and occurs as a post-transcriptional modification of the wobble base G34. Although it is found in both eubacteria and eucaryotes, its de novo biosynthesis is a unique property of eubacteria. We are investigating the biochemical pathway responsible for queuosine biosynthesis, with particular emphasis on the enzyme S-adenosylmethionine: tRNA ribosyltransferase-isomerase (QueA). QueA catalyzes the conversion of the ribosyl moiety of S-adenosyl-L-methionine (AdoMet) to the epoxycyclopentandiol residue of epoxyqueuosine (oQ), the penultimate intermediate in Q-biosynthesis. We have proposed a new chemical mechanism for this unprecedented reaction, and present experiments designed to test this proposal.

(Note - poster previously listed as # 118 has been withdrawn)
118. APPLICATION OF DHBA TO BLEACH HARDWOOD KRAFT PULP. Eileen O. Kutscha*, Barry S. Goodell**, Douglas M. Ruthven, and Joseph M. Genco, Department of Chemical Engineering and **Department of Wood Science and Technology, University of Maine, Orono, ME 04469.

It is hypothesized that non-enzymatic wood decay by brown-rot fungi occurs due to the formation of hydroxyl radicals in the presence of iron and hydrogen peroxide. It is also hypothesized that low molecular weight, iron reducing compounds produced by brown-rot fungi aid in the wood decay process. They may act as redox cyclers and promote the formation of cellulose depolymerizing hydroxyl radicals. The goal of this project was to mimic the mechanism of brown-rot decay to produce hydroxyl radicals at selective sites within the wood fiber in order to promote pulp bleaching. A synthetic fungal isolate, 2,3-dihydroxybenzoic acid (DHBA), was applied to Kraft brownstock in the presence of iron, oxalic acid and hydrogen peroxide. The effects of this novel treatment on pulp brightness, lignin content and cellulose degree of polymerization will be presented.

119. INHIBITORS AND ALTERNATE SUBSTRATES OF L-PIPECOLATE OXIDASE. S. N. Murthy, David L. Blanchard, and T. Mark Zabriskie*, College of Pharmacy, Oregon State University, Corvallis, OR 97331.

L-Pipecolic Acid (L-PA) is a product of L-lysine metabolism, which has been implicated as a modulator of gamma-aminobutyric acid (GABA) inhibitory neurotransmission in the central nervous system. L-PA is degraded in mammals by a flavin-dependant amine oxidase. We have evaluated several cyclopropyl-containing L-PA analogues as inhibitors or possible substrates of rhesus monkey liver L-pipecolate oxidase (L-PO) as part of continuing studies on developing inhibitors of L-PO as potential anticonvulsants. The preparation and inhibition properties of some of these compounds will be discussed.

120. MOLECULAR CLONING AND CHARACTERIZATION OF CAPREOMYCIN SYNTHETASE GENES FROM STREPTOMYCES CAPREOLUS. Xihou Yin1, Thomas O'Hare2, Steven J. Gould2,3 and T. Mark Zabriskie1,* 1College of Pharmacy and 2Department of Chemistry, Oregon State University, Corvallis, OR 97331 and 3Merck Research Laboratories-Basic Research, Rahway, NJ 07065.

Capreomycin is a clinically used antitubercular peptide antibiotic produced by Streptomyces capreolus A250. To facilitate mechanistic studies and investigate factors governing substrate specificity of the nonribosomal peptide synthetases involved in capreomycin biosynthesis we have launched efforts to clone the structural genes for this peptide and express the individual adenylation domains in surrogate hosts. This poster will detail the identification, cloning, mapping and sequencing of the capreomycin gene cluster, and the heterologous expression of the individual adenylation domains in E. coli and S. lividans.

121. DEMONSTRATION FROM MAGNETIZATION TRANSFER THAT A PROPOSED OXOCARBOCATION INTERMEDIATE DOES NOT HAVE A KINETIC LIFETIME IN THE REACTION CATALYZED BY YEAST OROTATE PHOSPHORIBOSYLTRANSFERASE. Ronald W. McClard, John F. Witte, and R. Tsou, Department of Chemistry, Reed College, Portland, OR 97202.

The gene for orotate PRTase from Saccharomyces cerevisiae has been subcloned into an E. coli overexpression vector and the enzyme has been produced in large quantities, thus simplifying the purification to one step. We were able to repeat the published 32PPi/PRPP exchange experiments and could demonstrate the exchange by magnetization inversion transfer NMR experiments as well. However, when contaminating OMP was eliminated with OMP decarboxylase, any evidence of magnetization transfer vanished. Consequently, it is concluded that a ping pong mechanism is not operable and that a previously proposed oxocarbocation intermediate along the pathway to OMP does not persist long enough in the catalytic cycle of this enzyme to be recognized by NMR exchange experiments.

122. NMR CHARACTERIZATION OF AN ASP-HIS CATALYTIC DIAD AT THE ACTIVE SITE OF PHOSPHATIDYLINOSITOL-SPECIFIC PHOSPHOLIPASE C. HYDROGEN BONDING AND DYNAMICS OF THE NH PROTONS OF HISTIDINE. Margret Ryan, Tun Liu, Frederick W. Dahlquist, and O. Hayes Griffith*, Department of Chemistry and Institute of Molecular Biology, University of Oregon, Eugene, OR 97403.

Phosphatidylinositol-specific phospholipase C (PI-PLC) comprise a diverse family of enzymes that catalyze the cleavage of the membrane lipid phosphatidylinositol (PI), or its phosphorylated derivatives, to produce diacylglycerol (DAG) and the phosphorylated myo-inositol headgroup. A catalytic diad at the active site of Bacillus cereus PI-PLC composed of Asp274 and His32 was postulated from the crystal structure. We have recently observed this catalytic diad directly by NMR. In the present study, the hydrogen bonding and dynamics are examined. The single low-field line in the 1H NMR spectrum is assigned by site-directed mutagenesis. The hydrogen is solvent accessible, and exchanges slowly with H2O on the NMR time scale. From the NMR data it can be classified as a normal, rather than a low-barrier hydrogen bond, which could become stronger in the transition state, contributing further to the catalytic efficiency.

123. ESTER BIOSYNTHESIS AND ALCOHOL ACETYLTRANSFERASE ACTIVITY DURING RIPENING OF "DELICIOUS" APPLES (MALUS DOMESTICA BORKH). David R. Rudell1, Scott Mattinson1, James P. Mattheis2, and John K. Fellman1*, 1Horticulture and Landscape Architecture, Washington State University, Pullman, WA 99164-6414 and 2USDA-ARS Tree Fruit Research Laboratory, Wenatchee, WA 98801.

Volatile esters are important components of our perception of fresh apple flavor, hence we are investigating maintenance of flavor attributes in 'Delicious' apples that are stored for off-season marketing. To date, there have been no studies that relate harvest timing and optimum volatile profiles after storage. Alcohol acetyl transferase (AAT) is the enzyme responsible for formation of volatile esters from primary alcohols and acetyl CoA in apples. We studied the relationship between ontogeny and the ability to synthesize esters as well as accumulation of the principal aroma and flavor volatiles(acetate esters) from 'Red Chief Delicious' apple fruits. Apples were sequentially harvested from the Pullman research orchard and evaluated for quality measurements, as well as AAT activity, internal ethylene concentration, and total purgeable volatile profiles. Evidence of esterification activity was found in cortex tissue disks prepared with apples from the earliest harvests and in partially-purified enzyme preparations. At color-break, AAT activity appeared in crude extracts and increased in purified fractions. This event appeared to correlate with a sharp decrease in average daily temperature. From that point, AAT activity was always measurable in crude extracts. AAT activity stayed at low levels until ethylene production occurred in the fruit, but was always closely linked to acetate ester content of the tissue. While AAT may not be the best indicator of harvest maturity for long-term apple storage, it may help in transduction of the ripening signal.

124. CYTOTOXIC AND ANTIFUNGAL STUDIES OF BIOLOGICALLY ACTIVE COMPOUNDS IN SANDSPURGE. Justin Frederick, Noel L. Owen*, and Steven G. Wood, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602.

Sandspurge (Euphorbia polycarpa Benth) is a common herbaceous plant of the American Southwest. It is used by the Yaqui Indian Tribe as an herbal remedy to treat snake bites, scorpion stings, and yeast infections. Using the "hole-in-plate" method, crude fractions were tested against Candida albicans to determine antifungal activity. Subsequent fractions were monitored for cytotoxicity was observed with a LD50 of 0.040 mg ml-1. The active components were subjected to further bioassay guided isolation using column chromatography, and structural identification was carried out using mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

125. PRODUCTION OF GENETICALLY MODIFIED HUMAN CYSTATIN C BY PICHIA PASTORIS. Masahiro Ogawa, Soichiro Nakamura, Shuryo Nakai*, and Christine H. Scaman, Department of Food Science, University of British Columbia, 6650 N.W. Marine Drive, Vancouver, BC, Canada V6T 1Z4.

Cystatin C, a cysteine proteinase inhibitor, is ubiquitous in mammalian tissues and fluids where it regulates cysteine proteinase activity. Human cystatin C (HCC) has potential pharmaceutical applications (i.e., in preventing metastasis of tumor cells and inhibition of viral replication). However, HCC is prone to inactivation, which may result from dimerization, proteolysis, and/or oxidization of methionine residues. Our objective in this study was to produce genetically modified HCC with high stability, using Pichia pastoris. A synthetic gene encoding HCC was designed using HCC amino acid sequence and P. pastoris preferred codons. Four oligonucleotides (each 115 bp) were synthesized, hybridized, and ligated. The resulting 0.4 kbp fragment was ligated into P. pastoris expression vectors pPICZa-A (for secretion) and pPICZ-B (for intracellular expression). To enhance the stability of HCC, N-glycosylation sites were introduced. Three single site variants, Asp-15*Asn, Ala-37*Ser, and Asp-81*Thr and one double site mutant, Ala-37*Ser, Asp-81*Thr were constructed, expressed and purified using E-64 papain chromatography. The HCC variants were expressed in P. pastoris as glycosylated protein. Amino acid sequence analysis showed that the glycosylated HCCs have N-terminal sequences identical with the native counterpart. On SDS-PAGE, the molecular weight of glycosylated HCCs was 25-30 kDa, while that of unglycosylated native HCC was 15 kDa. The HCC variants showed similar inhibitory activity against papain as the native HCC.

126. PURIFICATION AND STRUCTURE DETERMINATION ON HUPERAZINE A. Aibin You, WenDing Wang, 401 Pleasant View Court, Copaigue, NY 11726.

Huperazine A is an alkaloid which was first isolated from Chinese herb - Huperzia serrata. This product exhibits a significant anticholinesterase activity and has been used on myasthenia gravis patients. Purification and chemical structure determination were based on TLC and UV, IR, NMR and MS spectra. Stability studies on Huperazine A tablets were also performed.

127. HYPERICIN RETENTION AND ANTIOXIDANT ACTIVITY IN VACUUM MICROWAVE-DRIED ST. JOHN'S WORT (HYPERICUM PERFORATUM L.). Alex N. Yousif, Christine H. Scaman, Charles Hu, David D. Kitts, and Timothy D. Durance, Department of Food Science, University of British Columbia, 6650 N.W. Marine Drive, Vancouver, BC, Canada V6T 1Z4.

St. John' s Wort, {Hypericum perforatum (L}.) contains hypericin and other phenolics which have implications in the plant' s analgesic, antimicrobial, antioxidant and antidepressant activities. Air-drying of the herb substantially reduces the level of hypericin by up to 80%, possibly as a result of oxidation. The effects of drying method (hot air (AD), freeze (FD), and vacuum microwave (VMD)) on concentration of hypericin and the antioxidant activity of the plant were investigated. Hypericin was quantitated in extracts of plants dried by each method, using RP-HPLC. VMD and FD samples yielded higher concentrations of hypericin (28.6% and 37.1%, respectively) than AD samples. Antioxidant activity of extracts was evaluated using AAPH radical-induced peroxidation of soybean liposomes, and DPPH radical scavenging activity. Protection against AAPH induced liposome oxidation was greatest for VMD (72%) compared to AD (51%) and FD (58%). Extracts were also found to scavenge the stable DPPH radical, with FD (45%) and VMD (25%) both exceeding AD (20%) scavenging activity. These results indicated that drying method influences the retention of biologically active constituents of St. John's wort which may be involved in the antioxidant and antidepressant effects.

128. ADSORPTION OF PULMONARY SURFACTANT AT THE AIR/WATER INTERFACE. Vincent Schram and Steven B. Hall, Molecular Medicine, Oregon Health Sciences University, Portland, OR 97201-3098.

Pulmonary surfactant, a complex mix of lipid and proteins essential for normal breathing, reduces the surface tension at the air-water interface in the pulmonary alveoli. The present study focuses on the mechanisms of adsorption of pulmonary surfactant to the air-water interface. Measuring the surface tension with the Wilhelmy plate technique, we followed the kinetics of adsorption to a clean interface as a function of temperature and lipid concentration in the subphase. Calf Lung Surfactant Extract (CLSE), 1-palmitoyl-3-oleoyl-phosphatidylcholne (POPC) alone and in combination with the surfactant proteins (SP-B and SP-C) present in CLSE were investigated. Results show that the adsorption rate is dramatically increased by the presence of SP-B / SP-C and that both proteins strongly reduce the activation energy of fusion. Our data are compatible with a two step model in which the vesicles first accumulate at the air-water interface then fuse at a later stage.

129. FLUORESCENCE MICROSCOPY OF PULMONARY SURFACTANT MONOLAYERS AT AN AIR/WATER INTERFACE. Barbora Piknova and Steven B. Hall, Molecular Medicine, Oregon Health Sciences University, Portland, OR 97201-3098.

Many amphiphilic molecules that are almost insoluble in water can form a monolayer at the air/water interface. From the biological point of view, the most important monolayer is the one formed by pulmonary surfactant in alveoli of the lungs. There is general agreement about its principle role - to prevent alveoli from collapsing during the breathing cycle by decreasing surface tension at air/water interface. The average composition of the secreted surfactant has been extensively studied, but the composition and structure of the functional surfactant has been extensively studied, but the composition and structure of the functional surfactant monolayer in the alveoli remain unclear. Two main hypotheses about the structure/function relationship of pulmonary surfactant film have been formulated. The first proposes the refinement by adsorption/desorption of selective components during the breathing cycle to form the functional film. The second hypothesis considers reorganization of components into new two- or three-dimensional phases. We are using fluorescence microscopy to address the structure of the pulmonary surfactant film at the air/water interface.

130. A NEW CYCLOARTANE BISDESMOSIDE FROM THALICTRUM SQUARROSUM. A. S. Gromova, V. I. Lutsky, E. A. Khamidullina, D. Li, and N. L. Owen*, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602.

Thalictrum Squarrosum (fam. Ranunculaceae) - a Siberian plant, is a source of new, interesting triterpenoids. Some of them have been shown to have contraceptive properties. In the present poster the structure of the new saponin - Squarroside C - is presented. Squarroside C was isolated from the above-ground part of the plant. The molecular formula (C48H78O19) was obtained by high resolution mass spectrometry. The structure of this new saponin was established by 2D NMR spectroscopy to be 3-O-[O-a-L-rhamnopyranosyl-(1,6)-b-D-glucopyranosil] -21-O-b-D-glucopyranosil-3b,21,22,30-tetrahydroxy-21,23-epoxycycloart-24-en.

131. CHEMICAL COMPOUNDS AND PHYSIOLOGICAL ACTIVITY OF ASTRAGALUS DANICUS FROM EAST SIBERIA. V. I. Lutsky, A. S. Gromova, J. Cannon, D. Li, and N. L. Owen*, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602.

Various species of the genus of Astragalus (fam. Fabaceae) have been widely used in folk medicine in the Far East for treatment of a variety of ailments. Saponins of Astragalus danicus have not been studied systemically so far. We have studied the above-ground part of the plant, collected in Buryatiya (East Siberia, Russia) in 1998. Methanol and methylene chloride extracts show cytotoxic activity against a HeLa cervical cancer cell bioassay. The fat and wax components were removed from the methanol extract by chloroform. The residue was partitioned into a 1-butanol-water solvent system. We have isolated a few compounds by SiO2 column chromatography from the butanol soluble portion. The structures of some of them have been established by spectroscopic methods (IR, MS, and 2D NMR).

132. A REDOX-CONTROLLED, pH-DEPENDENT THYLAKOID PROTEIN KINASE: IS PLASTOQUINOL THE ACTIVATING LIGAND? Todd P. Silverstein1* and John F. Allen2, 2Plant Cell Biology Department, Lund University, S-220 07 Lund, Sweden and 1Chemistry Department, Willamette University, Salem, OR 97301.

The redox behavior of isolated pea thylakoid membranes was examined in the presence and absence of redox mediators, and at different pH's. Thylakoid membranes were redox titrated in situ, both with and without redox mediators. The major effect of the added mediators was to moderate changes in ambient potential. We examined redox activation of the thylakoid protein kinase and found that redox control of protein phosphorylation is virtually unaffected by redox mediators. Addition of redox mediators does improve both the accuracy and precision of the titration. Finally, redox titrations carried out in the presence of mediators at various pHs show that the average midpoint potential for redox-activated thylakoid protein kinase activity decreases linearly with pH, by 52 mV/pH unit. Below pH 9, the fitted value of n for these redox titration curves is approximately one; above pH 10 n is higher (approximately 2). Based on these data we propose that plastoquinone is the redox sensitive kinase-activating ligand in the thylakoid membrane.

133. COMPUTERS IN THE FIRST YEAR GENERAL CHEMISTRY LABORATORY: AN OVERVIEW. William J. Randall* and Gillian A. Gardner, Lewis & Clark College, Portland, OR 97219-7899.

An NSF-ILI grant was obtained to introduce computers into our First year General Chemistry Laboratory program. We reviewed two potential sources of interfaces and transponders and settled on LabWorks. We have adapted our laboratories to use the new equipment for the detection and measurement of temperature, pH, potential at silver electrode, pressure, and light intensity change. Several new experiments were implemented directly in this first year. We will present the impact of this renovation on the student perceptions and the quality and quantity of data and understanding that has resulted. We will also present the results of a surveys completed by students on their perceptions of the utility of this method of data collection.

134. COMPUTERS IN THE FIRST YEAR GENERAL CHEMISTRY LABORATORY: ACID-BASE TITRATIONS. Gillian A. Gardner and William J. Randall*, Lewis & Clark College, Portland, OR 97219-7899.

The LabWorks interface was connected to a pH electrode and a drop counter. The titration was monitored by recording the pH at the instant the drop counter detected a drop of titrant passing through. The pH was plotted as a function of volume (either drops or mL units) and the equivalence point was determined by use of a first derivative curve superimposed upon the titration curve. Students used this method of data collection for two experiments. In the first experiment they selected a sample from a variety of acids and bases and proceeded to determine the concentration of the sample. In the second experiment the determined the titration curve for an unknown diprotic acid, the two equilibrium acid dissociation constants for the acid and the molecular weight of the unknown. From these data they were able to identify the unknown. We will present the experimental details and a sample of the programs that monitored this experiment.

135. COMPUTERS IN THE FIRST YEAR GENERAL CHEMISTRY LABORATORY: DETERMINATION OF ABSOLUTE ZERO. William J. Randall* and Gillian A. Gardner, Lewis & Clark College, Portland, OR 97219-7899.

Using the pressure transducer and a thermistor, both attached to the LabWorks interface, students were able to measure the pressure at several temperatures. Using the statistical programs that are part of LabWorks they calculated the equation for a straight line fit to their data and predicted the value of the x-axis intercept which was interpreted to be the value of absolute zero. Students in this class collectively obtained a value of -277(±12)°C. We will present the experimental details and the EZ program that monitored this experiment.

136. COMPUTERS IN THE FIRST YEAR GENERAL CHEMISTRY LABORATORY: HEAT OF HYDRATION AND HEAT OF REACTION. William J. Randall * and Gillian A. Gardner, Lewis & Clark College, Portland, OR 97219-7899.

A simple calorimeter apparatus was constructed that consisted of two nested Styrofoam cups placed snugly in a beaker with a lid that accommodated a temperature sensor. Using LabWorks an EZ program was developed to measure the temperature as a function of time. Both dehydrated MgSO4 and MgSO4o7H2O were placed in the calorimeter that contained 100 mL of DI water in two separate runs. The heat of hydration was then calculated from the difference in the two heats of dissolution. The Heat of Reaction was measured for the reaction between a strong acid and a weak acid and NaOH. The DH for the ionization of the weak acid was then computed by a difference in the two determined values. We will present the experimental details, the EZ programs that monitored these experiments, and the results of these experiments.

137. COMPUTERS IN THE FIRST YEAR GENERAL CHEMISTRY LABORATORY: KINETICS OF THE IODINE CLOCK REACTION. Gillian A. Gardner and William J. Randall*, Lewis & Clark College, Portland, OR 97219-7899.

The LabWorks light sensor was used to determine the time it took for a given amount of reaction to occur. The immersion heater was used connected to an AC controller and to the output from the LabWorks interface. With this arrangement we could determine the times for reactions at both different concentrations of reagent and also different temperatures in successive experiments. The rate constant our class obtained was 4.44(±0.42)x10-3 L mol-1 sec-1. The class was able in a second week of experimentation to determine the activation energy of the reaction to be 45.2(±2.4) kJ/mol. We will present the experimental details and the programs that monitored these experiments.

138. COMPUTERS IN THE FIRST YEAR GENERAL CHEMISTRY LABORATORY: POTENTIOMETRIC DETERMINATION OF CHLORIDE. William J. Randall* and Gillian A. Gardner, Lewis & Clark College, Portland, OR 97219-7899.

The LabWorks interface was used to monitor the titration of chloride with silver nitrate. A silver wire working electrode and a Cu|Cu2+ reference electrode was connected to the mV input of the interface. At the same time a drop counter was used connected to the interface to monitor the titrant volume. A plot of the potential as a function of volume of titrant was displayed on the monitor; a first derivative curve was displayed superimposed upon the titration curve for identification of the equivalence point in the titration. Students used this procedure to first standardize their silver nitrate solution against a standard analyzed chloride sample and then to titrate an unknown chloride sample. We will present the experimental details, the programs that monitored these experiments, and the results.

139. CHEMISTRY CONCEPTESTS: HIGH TECH AND LOW TECH IN THE LARGE CLASSROOM. Cheryl Shirley, Jennifer Simonic, Thomas McComb, Gwen P. Shusterman, and Carl C. Wamser, Department of Chemistry, Portland State University, Portland, OR 97207-0751.

As class size increases, the ability to interact with students and accurately assess their comprehension on a real-time basis becomes more difficult. ConcepTests address these problems by allowing students to quickly express their understanding (or lack of understanding) and by allowing the instructor to assess and adapt to the needs of the students. ConcepTests are multiple choice questions posed by an instructor during a class; students respond directly by holding up colored signs corresponding to the possible choices. Even in large classes, the feedback can be quickly and easily monitored, announced, and reacted to. They are particularly useful for assessing baseline knowledge, connecting students' knowledge to a new topic, piquing interest, confirming understanding of a concept just covered, breaking the monotony of a lecture, and engaging students in peer discussions. We have used them extensively in the large lecture classes for both General Chemistry and Organic Chemistry, and student response has been positive. Our collection of ConcepTests is on our web site ( http://chem.pdx.edu/~wamserc/ConcepTests/ ), and they are being incorporated into the site at the University of Wisconsin ( http://www.chem.wisc.edu/~concept/ ).

140. MACROS FOR INSERTING CHEMICAL REACTIONS AND SCIENTIFIC NUMBERS INTO MICROSOFT WORD OR COREL WORDPERFECT DOCUMENTS. S. Scott Zimmerman, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602.

Typing chemical formulas and equations and typing numbers in scientific notation for class handouts, examinations, research papers, and other technical documents can be tedious and frustrating. To address this problem, I have written two macros, ChemEq and SciNum, that take unformatted input from the user and automatically convert it into the correct scientific format. For example, you can type the unformatted formula
3 Ca+2 + 2 PO4-3 > Ca3(PO4)2
and the ChemEq macro will insert the following formatted equation into your document:
3 Ca2+ + 2 PO43- Æ Ca3(PO4)2
for a savings of over 50 keystrokes. Similarly, you can type, for example, "1.7" and "-5," and the SciNum macro will automatically insert the number as 1.75 ¥ 10-5, with a typographic times sign (not just an x), with a minus sign (not just a hyphen), and with nonbreaking spaces on each side of the times sign.

141. TECHNIQUES THAT FACILITATE EFFECTIVE HIGH SCHOOL LAB WORK. David W. Trapp, Sequim High School, Sequim, WA 98382.

A collection of "tricks of the trade" that make intense laboratory instruction manageable will be presented. These techniques foster student laboratory work habits that match those of professional chemists, while making teaching more effective and often easier.

142. CHEMICAL APPLICATIONS AND ANALOGIES: THE "REAL" REASON WHY OIL AND WATER DON'T MIX, AND THE "BIG DOG-PUPPY DOG" ANALOGY FOR RESONANCE. Todd P. Silverstein, Chemistry Department, Willamette University, Salem, OR 97301.

Chemical applications use real world problems to demonstrate basic chemical concepts. Everyone knows that oil and water don't mix, but generations of chemistry textbooks have mistakenly relied on enthalpy to explain why this is the case. In fact, in most cases the mixing process is exothermic, so the immiscibility of the two liquids must be explained by a loss of entropy in the system. This "hydrophobic effect" is often explained thusly: water molecules form ice-like clathrate hydrate "cages" around non-polar solute molecules. The formation of these H-bonded solvent "cages" explains why both H and S are negative for the solution process, and the endergonicity of solvation is thus due to entropy and not enthalpy. Chemical analogies use simple stories to explain complex chemical phenomena. The "big dog-puppy dog" analogy is a wry visual scheme that helps to explain the nature of resonance structures, delocalized bonds, and fractional bond orders and formal charges. In this analogy, puppy dogs are restricted to a specific dog run; they represent s bond electron pairs. Big dogs (representing delocalized bond electron pairs) are allowed to roam freely over several consecutive dog runs. By adding a bunny rabbit who is chased by the big dog, the analogy can be expanded to account for delocalized formal charge in a resonance hybrid. This analogy presents a vivid, humorous picture that helps to explain some of the key aspects of resonance.

143. DECOMPOSITION OF ORGANIC POLLUTANT MODEL COMPOUND BY ELECTRIFIEDMICROHETEROGENEOUS CATALYSIS IN LOW IONIC STRENGTH AQUEOUS MEDIA USING TiO2 AND NaY-ZEOLITE CATALYSTS. Elizabeth J. Osburn Atkinson*, Zengqi Feng, and Debra R. Rolison, Chemistry Department, Linfield College, McMinnville. OR 97128.

Technologies that purify water or destroy water-soluble hazardous chemicals typically involve physical separation techniques and chemical transformations. Electrochemical oxidation is a favorable method for decomposing organic compounds and other oxidizable species in solution because oxidants may be formed in-situ. Electrified microheterogeneous catalysis (EMC) is a newly developed technique that oxidizes and decomposes organic compounds in low ionic strength media using dispersed catalysts. EMC experimental results with chlorinated aromatic model compounds indicate that a Pt anode is crucial for EMC degradation, implicating hydroxyl radical as the oxidative agent leading to EMC mineralization of chlorinated aromatics. Experimental results using TiO2 and NaY-Zeolites as dispersed electrodes have indicated quantitative decomposition of 3.5 mM 2,3-dichlorobenzoic acid during the EMC decomposition. The chloride content during the reaction increases linearly using chloride selective electrodes or capillary ion analysis. Monitoring the reaction in D2O using 1H-NMR over time confirms the quantitative destruction of 2,3-dichlorobenzoic acid using NaY and TiO2 as dispersed catalyst.

144. CO2 AND O2 VARIABILITY UNDER ICE-COVER IN PLACID LAKE, MT. Matthew M. Baehr*, and Michael D. DeGrandpre, Department of Chemistry, University of Montana, Missoula, MT 59812.

Temperate lakes are ice-covered for significant periods each year, however biogeochemical variability under ice has not been effectively characterized. In an effort to improve our understanding of variability under ice, long-term simultaneous time-series measurements of the partial pressure of CO2 (pCO2) and dissolved O2 have been performed on an underwater mooring. These in-situ data coupled with periodic profile data taken at the mooring site are being used to evaluate the processes controlling the gas variability under ice in Placid Lake, a mesotrophic lake in western Montana. Preliminary results reveal that the dominant processes controlling variability under ice are biological respiration, ice formation, and possibly seiche events.

145. THE DEVELOPMENT OF AN AUTONOMOUS SPECTROPHOTOMETRIC INSTRUMENT FOR IN SITU MEASUREMENTS OF FRESHWATER pH. Craig M. French, and Michael D. DeGrandpre*, Department of Chemistry, University of Montana, Missoula, MT 59812.

An autonomous spectrophotometric instrument is being developed for in situ freshwater pH measurements. The instrument operates by recording the absorbances of a thermodynamically characterized indicator (cresol red) mixed with the freshwater sample. The instrument consists of a miniature solenoid pump and valve, a fiber-optic flow cell, a low power data logger, and various other easy to acquire optical components. Laboratory tests produced a 3_ precision of ± 0.003 pH units and an accuracy of ± 0.015 pH units compared to results from a bench top spectrophotometer. The pH perturbation caused by addition of the indicator will also be discussed.

146. REMOVAL OF HEAVY METAL IONS BY SOL-GEL GLASS RESINS DOPED WITH ORGANIC DYES. Dong Liu, Trant T. Ho, and Jie Lin*, Department of Chemistry, Portland State University, Portland, OR 97207-0751.

A new type of materials called "sol-gel glass resins" have been developed by using sol-gel method for removal of heavy metal ions from contaminated waters and wastewaters. They were prepared by entrapment of organic dyes such as cibacron blue, cibacron brilliant red, and direct yellow in porous silica sol-gel glass. The resins were tested for the removal of Zn(II), Cd(II), and Pb(II) from aqueous solutions. The rate of removal, the removal as a function of metal concentration, and the effect of pH on the removal were studied, and the results will be presented and discussed. Our preliminary work demonstrated that the removal was an ion-exchange process and that the resins could be regenerated and reused repeatedly. Future studies will be made to prepare the sol-gel glass resins by using complexing and chelating reagents.

147. DETERMINATION OF PLUTONIUM IN SEQUENTIALLY EXTRACTED SEDIMENTS. Stacey M. Loyland*, Sarah Herbison, Tom Hinton,** and Sue B. Clark, Washington State University Chemistry Department, Pullman, WA 99164-4630 and **University of Georgia Savannah River Ecology Laboratory, Aiken, SC 29808.

Pond B, a warm monomictic reservoir on the Savannah River Site, South Carolina, has elevated concentrations of 238Pu and 239,240Pu in sediments due to releases from former reactor operations. The seasonal cycling of plutonium in Pond B of the Savannah River site is well documented. However, a fundamental understanding of the natural geochemical cycles that influence the mobility of plutonium in aquatic systems remains elusive. Cycling may be linked to the chemical partitioning of Pu to specific components of the sediment. The distribution of Pu in the contaminated sediments is being investigated by sequential extractions. Our observations will be presented and discussed in the context of possible mechanisms that may result in the release of Pu during periods of anoxia.

148. CONTINUING STUDIES OF THE ENVIRONMENTAL FATE AND EFFECT OF AIRCRAFT DEICING FLUIDS. Devon A. Cancilla*, Shannon Scullin, and Maya Belka, Huxley College of Environmental Studies, Western Washington University, Bellingham, WA 98225-9181.

Aircraft deicing fluids are used at almost every airport in the world. With the average commercial plane requiring roughly 3000 liters of deicing fluid, total airport usage can run into the many thousands of liters over a typical deicing season. As airports vary in their ability to collect or treat these fluids, the release of these fluids into the environment has recently become a significant issue. In particular, recent studies have shown these fluids to have toxic effects to a variety of aquatic organisms. Recently, our group has identified constituents from deicing solutions in groundwater systems under a major North American Airport. This paper describes the results of ongoing studies to determine the environmental fate and effect of aircraft deicing fluids through both chemical and toxicological assessments

149. SMALL MOLECULE BINDING TO A COBALT(II)-ASSEMBLED CAGE MOLECULE. Danny O. Fox, Jenny Leung, Kent N. Dalley, and Roger G. Harrison*, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602.

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Metal assembled cage complexes are of interest for their molecular recognition properties. The synthesis and X-ray crystallographic structure of a cage molecule assembled by four cobalt(II) ions and created from two cup shaped, iminodiacetate-functionalized resorcinarene molecules is presented. The dimensions of the cage indicate it is large enough to host small molecules. NMR studies show the existence of cage in solution is pH dependent and small molecules like benzene, ether, and hexane are encapsulated by the cage. Solid-state structures also show small molecules encapsulated within the cavity. The water soluble cage complex provides a hydrophobic cavity within a hydrophilic medium.

150. SYNTHESIS AND REACTIVITY OF LRe(O)X2 AND LRe(O)XY COMPOUNDS. Fedor A. Zhuravlev and Kevin P. Gable*, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

Intermediacy of a metallaoxetane in the oxidation of alkenes remains unproven. One rigorous test for it would be an isolation of a metallaoxetane of interest and investigation of its kinetic behavior. Specifically, our goal is to establish whether a metallaoxetane is a kinetically competent intermediate in bishydroxylation/cycloreversion reaction in the LReO3 - alkene system. To this end, a series of hydrotris- (Tp) and tetrakis- (Tk) pyrazolylborate rhenium oxo compounds of a general formula LRe(O)X2 and LRe(O)XY has been synthesized. Chemical transformations, potentially leading to rhenaoxetane are discussed.

151. STUDIES ON THE SYNTHESIS OF POLYMER-CONTAINING NANOCOMPOSITE MATERIALS BY A MELT-INTERCALATION PROCESS. Nipaka Sukpirom, Christopher O. Oriakhi, and Michael M. Lerner*, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

The preparation of polymer containing nanocomposite materials by a melt-intercalation process is demonstrated. KCdPS3, KMnPS3, LiMoO3 and LiMoS2 are used as host materials and structural details are investigated by powder X-ray diffraction. The intercalation of poly(ethylene oxide) PEO, poly(ethylenimine) PEI and poly(vinylpyrrolidone) PVP are evaluated between 20C and 125C.

152. TERNARY TRANSITION-METAL GERMANIUM ANTIMONIDES. Allison M. Mills and Arthur Mar,* Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2.

The intermetallic compounds Co3Ge2Sb and Fe3Ge2Sb0.8 have been prepared and characterized by single-crystal X-ray diffraction. They adopt structures that are closely related to, but intermediate between, the CoSn and CaCu5 structures. The presence of additional interstitial sites between the nets of transition metal atoms suggests that they can be filled by other foreign atoms, in analogy with RFe6Ge6 (R = Li, lanthanides, or early transition metals). Results from investigations towards this aim are presented

153. FUNCTIONALIZED GOLD NANOPARTICLES; A STUDY ON THE EFFECT OF INCORPORATING A PROTEIN BINDING LIGAND INTO AN ALKANETHIOL PASSIVATED NANOPARTICLE. Walter W. Weare, Scott M. Reed, and James E. Hutchison*, Department of Chemistry, University of Oregon, Eugene, OR 97403-1253.

Assembly of nanoparticles into useful electronic, optical, and sensing devices would be greatly facilitated by an ability to react nanoparticles to surfaces, templates and other nanoparticles with a high level of site-specificity. Our approach aims to individually functionalize gold nanoparticles with known protein binding ligands, enabling the templating of nanoparticle-protein conjugates at an air/water interface. Previously, we have shown that alkanethiols provide size-control, stability, and high solubility in organic solvents. Attaching a single protein binding ligand to gold nanoparticles while maintaining high solubility is a challenge in realizing our approach. Here we present a study of terminally functionalized thiols, where we demonstrate that ligand-exchange reactions which vary the ratio of passivating to functionalized ligands result in control over solubility and reactivity. Of particular interest is a nitrilotriacetic acid based ligand known to bind His-tagged proteins. UV/Vis Spectroscopy, X-ray Photoelectron Spectroscopy, and Transmission Electron Microscopy are used to determine nanoparticle functionality and size dispersity.

154. SOLID-STATE NMR STUDIES OF CHEMISTRY OF MOLECULARLY ENGINEERED NANOMATERIALS THROUGH TEMPLATING. Li-Qiong Wang, Jun Liu, Xiao-Yi Gong, and Gregory J. Exarhos*, Pacific Northwest National Laboratories, Richland, WA 99352.

Both 29Si and 13C solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy methods have been applied to study chemistry of materials synthesized through templating. In this study, templating molecules include not only conventional surfactant molecules forming micelles for the synthesis of ordered mesoporous materials but also individual molecules through molecular imprinting. In addition to the investigation of structure and dynamics of templating molecules in the synthesis of molecularly engineered nano-materials, the mechanism of surface modification to increase the materials stability has been examined using solid-state NMR spectroscopy. Functional groups and side groups in templating molecules were identified from high resolution spectra, while information on how surfactants organized onto silicates and their relaxation behavior were obtained using a combination of NMR line-shape and relaxation-time analyses with variable temperature NMR.

155. THE AQUEOUS CHEMISTRY OF MOLYBDOCENES - INTRA- AND INTERMOLECULAR H/D EXCHANGE VIA C-H ACTIVATION. Christoph Balzarek and David R. Tyler*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Aqueous solutions of Cp'2MoCl2 or [Cp'2Mo(µ-OH)2MoCp'2][OTs]2 (Cp' = h5-C5H4CH3) have been found to promote H/D exchange with the D2O solvent at neutral pH. This exchange occurs for the methyl groups of the Cp' ligand in an intramolecular reaction. The intermolecular H/D exchange takes place with alcoholic substrates, resulting in deuteration of the alcohols primarily at the a-carbon. The key step in this exchange reaction is the insertion of the molybdenum center into a carbon-hydrogen bond. This is a rare example of C-H bond activation in aqueous solution. The scope of this exchange reaction as well as details about the mechanism will be presented.

156. TITANIUM-MEDIATED SYNTHESIS OF TETRA-SUBSTITUTED PYRIDINES. Eden A. Reed and Kenneth M. Doxsee*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Dimethyl- and diethyl-titanacyclobutenes, prepared from Cp2TiCH2.Al(CH3)2Cl (Tebbe's reagent) and the appropriate alkynes, react smoothly with nitriles to afford metallacyclic products which yield asymmetrically tetra-substituted pyridines upon acidification with HCl. We have developed a multi-step one-pot procedure starting from Tebbe's reagent which affords the tetra-substituted pyridines in comparable yields as the step-wise process but without the need for isolation of any metallacyclic intermediates.

157. AFM AND STM STUDIES OF SiO2. Steven Moskowitz and Thomas E. Engel, Department of Chemistry, University of Washington, Seattle, WA 98195.

The growth of SiO2 and the structure of the Si-SiO2 interface are two critical areas of study today. The need to understand, and grow, uniform, flat, thin-film SiO2 on Si is of major importance in the production of microelectronic devices. Currently most research and industrial processing is done by growing the oxides under a high O2 pressure at high temperatures, which allows for > 1 ml growth. At room temperature O2 is self-limiting at 1ml, but using O as the reactant allows for films up to 15 ml to be grown. In the current research, thin films at room and elevated temperatures grown with atomic oxygen are studied. These films are probed with STM and AFM to observe the effects of reactive species (O vs O2) and the effects of temperature on oxide growth and interface structure.

158. CAPILLARY FORCE MEASUREMENTS CONDUCTED BY ATOMIC FORCE MICROSCOPY AND THE HYPOTHESIS OF WATER VAPOR STRUCTURING. Mingyan He1, Amy Szuchmacher2, Eric Aston1, and René M. Overney1, 1Department of Chemical Engineering, and 2Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195.

Recent measurements with atomic force microscope (AFM) on mica revealed drastic drops in the pull-off forces at low humidities (1, 2). The force drop resembles a phase transition if assuming that the adhesive interactions are dominated by capillary forces. We tested the hypothesis of water vapor structuring at low humidity by conducting experiments with functionalized and bare AFM probes. We chose a silicon oxide surface as the substrate. The AFM probe surfaces were hydrophilic silicon oxide and hydrophobic silane-coated silicon tips. Our measurements showed that the pull-off forces are low and humidity-independent for the hydrophobic tip. We conclude that for hydrophilic surfaces, the capillary meniscus disappears below a certain humidity threshold. This research shows that indirect structural interpretations based on force measurements can be misleading. The paper will further discuss the effect of micro- and nano-contact on capillary forces, provide a modified capillary force equation for nano-contacts, and illustrate the effect of high humidity on pull-off forces.
1. L. Xu, A. Lio, J. Hu, D. F. Ogletree, and M. Salmeron, J. Phys. Chem. B 102, 540 (1998).
2. T. Thundat, X.-Y. Zheng, G. Y. Chen, and R. J. Warmack, Surf. Sci. Lett. 294, L939 (1993).

159. THE STABILITY AND SYNTHESIS OF STRONTIUM TITANATE LAYERED PEROVSKITES IN MOLTEN SALT FLUXES. Jeanette M. Blaine and Margret J. Geselbracht*, Department of Chemistry, Reed College, 3203 SE Woodstock Blvd., Portland, OR 97202.

Ruddlesden-Popper-type layered perovskites with the general formula A'2[An-1BnO3n+1] are layered oxides built up from perovskite-type slabs interleaved by layers of alkali metal or alkaline earth metal cations. These materials often show interesting structure-property relationships such as the recent discovery of colossal magnetoresistance in Ruddlesden-Popper-type layered manganates. We have begun to explore structure-property relationships in similar layered strontium titanates. In any given series of compounds, as n increases, the thickness of the perovskite-type slab increases. For example, the perovskite-type slabs evolve from a single layer of corner-shared TiO6 octahedra in Sr2TiO4 (n = 1) to a perovskite slab containing three corner-shared TiO6 octahedra in Sr2[Sr2Ti3O10] (n = 3) to an infinitely thick three-dimensional network of corner-shared TiO6 octahedra in SrTiO3 (n = ). These materials are traditionally prepared by solid state reaction of the binary oxides, requiring very high synthesis temperatures. We have been investigating new synthetic routes to the Ruddlesden-Popper titanates at lower temperatures. Toward this end, we have been exploring the chemistry of two phases, Sr2TiO4 and Sr3Ti2O7 in molten salt fluxes. Our results on the stability and synthesis of these phases in NaCl, KCl, RbCl, and SrCl2 fluxes will be described.

160. A COMPARISON OF THE NEUTRAL AND PROTONATED FORMS OF A SYNTHETIC HISTIDINE-TYROSINE ANALOG: SOLUTION AND STRUCTURAL PROPERTIES. Peter J. Pessiki*, Brian Paulsen2, Ira Bennett1, Douglas M. Ho,3 and G. C. Dismukes3, 1The Evergreen State College, Lab 1, Olympia, WA 98505, 2Department of Chemistry, Southern Oregon University, Ashland, OR 97520 and 3Department of Chemistry, Princeton University, Princeton NJ 08544.

Our approach to probing the hydrogen-bonding interaction between the amino acid residues tyrosine and histidine is to synthesize small organic molecules that contain the appropriate functional groups. Compound 1 (R = CH3) has been prepared and characterized by X-ray analysis in both its neutral and protonated states. Differences in hydrogen-bonding motifs are observed and will be reported. EPR spectra for the neutral phenoxyl radical produced by UV photolysis of frozen solutions of the deprotonated anion reveal coupling to an exchangeable proton. This is assigned to an intramolecular H-bond to the imidazole NH proton. Solution studies related to the protonation and metal coordination of 1 and similar molecules will also be presented.

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161. A COMPUTATIONAL INVESTIGATION OF THE STABILITIES OF CYCLOPROPYLCARBENES. Woonphil Baik* and Peter K. Freeman1, Department of Chemistry, Myong Ji University, Yong In, Kyung Ki Do, 449-728, Korea and 1Department of Chemistry, Oregon State University, Corvallis, Oregon 97331.

The conformations of dicyclopropyl, isopropyl cyclopropyl, and diisopropylcarbenes have been optimized using density functional theory. It is shown that the optimized geometries of carbenes with cyclopropyl groups are fully in accord with those expected for the bisected W-shaped conformations, in which the effective hyperconjugation of cyclopropyl group with singlet carbene can occur. The stabilization energies were evaluated at the B3LYP/6-311+G(3df, 2p)//B3LYP/6-31G(d) + ZPE level using the isodesmic equation. The decreasing order of relative stability of carbenes was displayed to be (c-Pr)2C: > (i-Pr)(c-Pr)C: > (i-Pr)2C:, and one cyclopropyl group stabilizes carbene more than isopropyl group by nearly 9 kcal/mol. From the singlet-triplet energy gap (EST) calculation, singlet level is lower than triplet and the EST shows the similar trend with stabilization energies. The optimized geometries and stabilization energies for the corresponding carbocations and alkanes have also studied at the same level cal

162. AB INITIO COMPUTATIONAL STUDY OF THE COPE REARRANGEMENT OF SYN-7-ALLENYLNORBORNENE. James A. Duncan, Joseph K. Azar, J. Callan Beathe, Carolyn M. Wulf, and Scott R. Kennedy, Department of Chemistry, Lewis and Clark College, Portland, OR 97219.

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163. COMBILEXINS WITH RIGID TETHERS: MOLECULES DESIGNED TO NOT BIND B-DNA. Nick R. Natale*, Kevin Hobdey, and Devin D. Bolz, Department of Chemistry, University of Idaho, Moscow, ID 83844-2343.

We have found that a rigidly tethered intercalator-minor groove binding combilexin, NSC D 694332, has single digit micromolar inhibition of a dozen tumor cell lines in the National Cancer Institute screening Program. Examination of molecular models, however, has led us to the conclusion that B-DNA is not the ideal target for this substance. We have hypothesized that NSC D 694332 may exert its biological effect by binding to a topology of DNA essential to the disease process. Analogs designed to probe this hypothesis will be described, as well as synthetic approaches to a combination intercalator-minor groove binding-microgonotropin association.

164. 2D NMR STUDIES OF NITROUS ACID CROSS-LINKED DUPLEX DNA. N. B. Fredrik Edfeldt, Eric A. Harwood, Snorri T. Sigurdsson, Paul B. Hopkins, and Brian R. Reid, Department of Chemistry, University of Washington, Seattle, WA 98195.

Nitrous acid is a mutagenic agent formed from the food additive sodium nitrite. It induces interstrand cross-links in double-helical DNA, preferentially at d(CpG) steps, linking the two deoxyguanosines on opposite strands via a single shared exocyclic amino group. Recent synthetic advances have allowed the production of large quantities of homogenous cross-linked duplex DNA. Here we present 2D NMR studies of two cross-linked duplexes: [d(GCATCCGGATGC)]2 and [d(CGCTACGTAGCG)]2 (the cross-linked guanines are underlined). These two sequence contexts (CCGG versus ACGT) were previously found to be the most efficient in forming cross-links. In both cases the cytosines 5' to the cross-link are extrahelical and located in the minor groove. The flanking sequence significantly alters the structure of the cross-link, particularly in the stacking of the cross-linked guanines with the bases 5' to the extrahelical cytosines (C or A). In addition to providing the first structure of a nitrous acid DNA cross-link, these studies could be of major importance in understanding the mechanisms of nitrous acid cross-linking and mutagenicity, as well as the mechanisms responsible for repair in intracellular environments.

165. ISOLATION AND IDENTIFICATION OF ANTICANCER COMPOUNDS FOUND IN GHANAIAN CARICA PAPAYA. Joshua P. Walsh, Kurtis S. Staples, Steven G. Wood, and Noel L. Owen*, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602.

The Pawpaw plant is used in Ghana to treat various illnesses from hypertension to cancer. Every part of the plant is used as herbal medicine. In our laboratory, extracts from the leaves of the tree have shown cytotoxic activity against HeLa cervical cancer cells, with an LD50 of purified fractions being less than 12.5 µg/ml. Silica gel CC and preparative HPLC techniques have been used to isolate and purify active agents. Once pure, mass spectrometry, and both 1D and 2D nuclear magnetic resonance spectroscopy will be used to elucidate the structure of the compound(s) responsible for the observed anti-cancer activity.

166. ISOLATION OF BIOLOGICALLY ACTIVE COMPOUNDS IN KRAMERIA PARVIFOLIA. Kristy L. Metcalf, Steven G. Wood, and Noel L. Owen*, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602.

Due to the widespread effects of cancer, finding new cytotoxic agents effective in cancer treatment is of great importance. Medicinal plants provide good sources for new and unique cytotoxic chemicals. Krameria parvifolia is a plant used by the Yaqui Indian tribe for its anti-cancer activity as well as its antimicrobial properties. Preliminary biological assay results indicate Krameria as a potential source of novel, cancer-treating compounds. The active compounds have been largely separated using bioassay guided extractions and silica gel chromatography.

167. LEWIS ACID PROMOTED NUCLEOPHILIC OPENING OF OXABICYCLO[3.2.1]-HEPTADIENES IN HIGHLY POLAR MEDIA. Paul A. Grieco* and Kevin W. Hunt, 325 Gaines Hall, Montana State University, Bozeman, MT 59715.

Nucleophilic addition to the bridgehead position of activated 8-oxabicyclo[3.2.1]heptadienes has been achieved in good yield utilizing the highly polar medium lithium perchlorate-diethyl etherate (LPDE). The reaction displays good to excellent stereoselectivity and is completely regioselective. The resulting cycloheptadienes are highly functionalized and readily manipulated for use as building blocks containing the anti,anti stereotriad. This methodology has been successfully incorporated into efforts toward the syntheses of Scytophycin C and the Kishi C19-C27 fragment of Rifamycin S.

168. MODELS FOR RADICAL TRAPPING IN INTACT CELLS. Casey S. Butterfield*, Nick R. Natale, Department of Chemistry, University of Idaho, Moscow, ID 83844-2343 and John K. Fellman, Department of Horticulture and Landscape Architecture, Washington State University, Pullman WA 99164-6414.

Farnesyl Protein Transferase (FPT) is involved in post translational processing of proteins essential to normal cell function. Malfunction of FPT is implicated in numerous disease processes, and we have postulated that radical damage to farnesyl derivatives leads to covalent inactivation of FPT, and hence to cell damage and ultimately to cell death. In model systems designed to test this hypothesis, Guaiazulene nitrone traps Farnesyl derivatives to produce a product which, after isolation and chromatography, exhibits a molecular ion in the mass spectrum corresponding to incorporation of two farnesyl substituents. Further characterization of the model reaction products, and experiments conducted on intact cells will be discussed.

169. NEW TRI- AND TETRA-SUBSTITUTED ADAMANTANES AS KEY PRECURSORS FOR THE SYNTHESIS OF MOLECULAR TIPS FOR AFM. Pavel A. Petukhov, Aleksey V. Rukavishnikov, Avinash Phadke, Donald LaMunyon, Melissa D. Lee, and John F. W. Keana*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Specially designed rigid molecules bound to the surface of available sharp AFM tips could significantly improve the resolution of AFM. We report here the synthesis of several 1,3,5- and 1,3,5,7-substituted adamantanes, which after attaching "legs" X and macrocyclization provide a series of relatively rigid tripodal molecules. A key reaction is the assembly of 1 using a Sonogashira coupling reaction. The flexibility of this synthetic approach allows ready synthesis of molecules of different size, shape and physicochemical properties that may satisfy specific needs of AFM imaging and other applications.
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170. STUDIES ON STERICALLY HINDERED NITRILE OXIDE CYCLOADDITIONS. Xiaochun Han and Nick R. Natale*, Department of Chemistry, University of Idaho, Moscow ID 83844-2343.

Promising biological activity for a lead compound has encouraged us to expand our study of the Nitrile Oxide Cycloaddition (NOC) in systems which have formidable steric hindrance. We had previously reported that anthracenyl 9-nitrile oxide adds readily to enamines to produce 3-(9'-anthracenyl)-isoxazole-4-carboxylates in moderate to good yields, with excellent regioselectivity (J. Heterocyclic Chem., 1995, p.779). We have examined this nitrile oxide in other cycloadditions, and found that other dipolarophiles are useful. Conversely, addition of simple nitrile oxides to the anthracenyl-9-acrylic acid ester derivative produces moderate yield of cycloadducts, in approximately a 5:1 ratio of regioisomers, the regiochemical assignment is based on NMR chemical shifts and previous model studies, and will be described. Attempts to extend this study to anthracenyl 9-3'-propiolic acid esters will be discussed.

171. SYNTHESIS OF 2,7-DISUBSTITUTED INDOLIZIDINES: A GENERAL PROCEDURE. Amir P. Tamiz, Gian Luca Araldi, Eric L. Pacini, Timothy J. R. Weakley, and John F. W. Keana*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

As part of our efforts to identify new subtype selective N-methyl-D-aspartate (NMDA) receptor antagonists, a synthetic procedure for the preparation of 2,7-disubstituted indolizidines was required. None of the existing methods were readily applicable to the specific substitution pattern needed for the envisaged structure-activity relationship study. We report the synthesis of a series of indolizidine based molecules, using 2-chloromethyl-4-benzylpyridine (1) as a key intermediate.
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172. SYNTHESIS OF A CHIRAL ETHYLENEDIAMINE DERIVATIVE VIA REDUCTIVE AMINATION OF ETHYL GLYOXALATE. Takashi Nakai and Patrick G. McDougal*, Department of Chemistry, Reed College, Portland, OR 97202.

As part of a study directed towards the synthesis of semi-synthetic analogs of bacitracin A, we had need to prepare chiral ethylenediamine derivatives. After several alternative routes failed, we found that the reductive amination of ethyl glyoxylate with chiral amines gives the target compound in good yield. Attempts to extend the reductive amination reaction to other keto ester derivatives will be presented.
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173. SYNTHESIS OF 2,3-DIHYDROPYRIDINES. T. Nicholas Jones and Cynthia K. McClure*, Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717.

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174. SYNTHESIS OF A NEW FLUOROGENIC SUBSTRATE FOR THE CONTINUOUS ASSAY OF MAMMALIAN PHOSPHOINOSITIDE-SPECIFIC PHOSPHOLIPASE C. Aleksey V. Rukavishnikov,a Tatiana O. Zaikova,a,b G. Bruce Birrell,b, John F. W. Keana,a and O. Hayes Griffith*a,b, aDepartment of Chemistry and bInstitute of Molecular Biology, University of Oregon, Eugene, OR 97403.

A new fluorogenic substrate for continuous assay of mammalian phosphoinositide-specific phospholipase C was synthesized starting from myo-inositol and fluorescein. The substrate, D,L-myo-inositol 4,5-bis(dihydrogenphosphate) 1-([6'-hexyloxy-3-oxo]spiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3'-yl hydrogen phosphate) (1), in the absence of PI-PLC, exhibited a low level of fluorescence, which was stable with time. Addition of recombinant human PI-PLCd1 to an aqueous solution of substrate resulted in a steady rise in fluorescence due to the formation of fluorescein derivative 2.
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175. SYNTHESIS OF NEW PROBES OF ACETYLCHOLINESTERASE. Jennifer Saltmarsh and Charles Thompson, Department of Chemistry, University of Montana, Missoula, MT 59812; Aileen Boyd, Zoran Radic, and Palmer Taylor, Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093.

Acetylcholinesterase (AchE) is the enzyme responsible for the hydrolysis of the neurotransmitter acetylcholine. Despite a long history of study, only in the past decade as the protein been crystallized and key structural information been elucidated. Central to understanding AchE has been the manner in which substrates and inhibitors are recognized and transported via a "gorge" to the active site. Our research has focused on the preparation of fluorescent probes attached to reactive organophosphate (OP) groups via a tether of known atomic length. The aim of the work is to study the environment and structure of the AchE gorge varying the tether length and nature of the reporter group. The design and synthesis of pyrene- and dansyl-containing reactive OP's that will attach to the active site serine and probe the gorge of AchE will be presented in addition to preliminary data on the OP-probes.

176. UNEXPECTED RESISTANCE OF 2,5-DIMETHOXYANILIDES TO ELECTROPHILIC CYCLIZATION. Ana C. Barrios and Kevin P. Gable, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

In an attempt to synthesize 5,8-dihydroxy-3,4-dihydroquinolin-2-one, several electrophilic approaches failed, including intramolecular Friedel-Crafts and proton-induced aza-Cope reactions. This failure can be traced to the absence of any HOMO contribution by the desired carbon atom.
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177. USE OF THE OXA-DI-PI-METHANE PHOTOREARRANGEMENT TOWARD THE SYNTHESIS OF HELIOTRIDINE. Cynthia K. McClure*, Jeffrey S. Link, and Anthony J. KiesslingÝ, Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717; ÝWilkes University, Department of Chemistry and Biochemistry, Wilkes-Barre, PA 18766.

Irradiation of enone 1 under triplet sensitized conditions (i.e., acetophenone or acetone) has been shown to yield tricycle 2 in good yield. Nucleophilic ring-opening using CF3CO2TMS should yield bicycle 3. Derivatization of 3 by subsequent reduction and protection steps should yield heliotridine, 4.
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178. PRINCIPLES FOR DESIGN OF ORDERED, STRATIFIED, SELF-ORGANIZED SUPRAMOLECULAR ASSEMBLIES. Robert S. Clegg, Scott M. Reed, Rachel K. Smith, and James E. Hutchison*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403-1253.

Comparing structures of SAMs with systematically varied polar amide underlayers and hydrophobic alkyl overlayers reveals structural principles for designing ordered SAMs. We have determined the dependence of supramolecular structure upon molecular constitution in a series of stratified, amide-containing, alkanethiol self-assembled monolayers (SAMs). Alkyl chains adjacent to amide underlayers are destabilized compared to n-alkanethiols, and amide regions can dominate over metal-adsorbate epitaxy in establishing assembly structure. Interactions between sublayers and lateral interactions within sublayers form the basis for two types of buried organic interfaces: rigid-elastic interfaces, with alkyl chains epitaxially ordered upon amide "templates;" and elastic-elastic interfaces, with amide underlayer structures controlled by lateral stabilizing interactions within the hydrocarbon overlayers. Elastic-elastic interfaces demonstrate the previously unreported induction of order in assembly sublayers by altering adjacent overlayers. These results have broad implications for rational design of SAMs, self-assembled multilayers, and bulk hybrid materials and for biological interfacial structure and function.

179. SYNTHESIS OF PEPTIDE CONTAINING ALKANETHIOLS. Athena Klock, Scott M. Reed, Rachel K. Smith, James E. Hutchison*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403.

Previously, we have shown that peptide containing alkanethiols are more stable than straight-chain alkanethiol monolayers on gold. Investigating the effect that different amino acids have on the structure and stability of these monolayers will require a novel synthetic route which is general to all amino acids and addresses the issue of racemization. Here we will present such a route, in which the molecule is formed starting from an acetyl protected sulfur coupled to an amino acid. N-deprotection followed by coupling of a t-butyl protected amino acid is repeated until the desired number of peptides is on the molecule. A variety of alkane tails can be added, and the final step of the procedure is deprotection of the thiol followed by ethanol adsorption onto gold. The monolayer is then studied by XPS, IR and CAG.

180. BIS(PERFLUOROPHENYL AZIDES) AS HIGHLY EFFICIENT CROSSLINKING AGENTS FOR POLY(VINYL PHENOL). Mingdi Yan#Ý*, Martin N. Wybourne¦, and John F. W. KeanaÝ, Departments of ChemistryÝ and Physics,¦ University of Oregon, Eugene, OR 97403 ; #Present address: Department of Chemistry, Portland State University, Portland, OR 97207-0751.

Negative photoresists based on poly(vinyl phenol) (PVP) have been developed using bis(perfluorophenyl azides). Examples of bisPFPAs include 1,5-bis(4'-azido-2',3',5',6'-tetrafluorophenyl)-1,4-pentadiene-3-one (4) and 2,6-bis(4'-azido-2',3',5',6'-tetrafluorophenylmethylene)-4-methylcyclohexanone (5). The use of long wavelength bisPFPAs makes it possible to carry out crosslinking reactions at near UV region (around 350 nm). These bisPFPAs exhibit high crosslinking efficiencies towards PVP. Addition of only 1.8 wt % of the crosslinker to PVP gave more than 70% of film retention after development. PVP resists containing 3.6 wt % of bisPFPA yield films with 95% retention.

181. MISCIBILITY OF A SOLID-SOLID PHASE-CHANGE MATERIAL COMPOSED OF CELLULOSE AND POLY(ETHYLENE GLYCOL). Xue-Hai Liang, Yuan-Qiang Guo and Lian-Zhen Gu, LCLC, Guangzhou Institute of Chemistry, Chinese Academy of Sciences, P. O. Box 1122, Guangzhou, China 510650.

A polyethylene glycol (PEG) - cellulose (CELL) blend which exhibited a solid-solid phase transition and could be used as a thermal energy storage material was prepared from solution in dimethyl sulfoxide (DMSO)/paraformaldehyde (PF). The state of miscibility of the blend obtained over the composition range of 95/5 to 30/70 was characterized by X-ray diffraction and differential scanning calorimetry. The results indicated that crystallinity and phase transition temperature of PEG within the blends decreased with increasing content of CELL. An analysis of phase transition depression showed that CELL and PEG within the blends were miscible. The investigation with Fourier-transform infrared (FTIR) spectroscopy demonstrated that there was a strong intermolecular hydrogen bond between these two components, which perhaps was the intrinsic reason why CELL and PEG exhibited a high level of miscibility in the blend.

182. SYNTHESIS OF 2-DEOXY-2-PHOSPONOMETHYL-D-ARABINOSE AS A POSSIBLE KDO SYNTHETASE INHIBITOR. Todd R. Boehlow and Cynthia K. McClure*, Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717.

Gram-Negative bacteria metabolize D-arabinose to produce 3-deoxy-D-manno-2-octulosonic acid (KDO) which is used in the production of lipopolysaccharides (LPS) for the bacteria cell wall. The 2-hydroxy group of D-arabinose eventually becomes the 5-hydroxy group of KDO and it is this hydroxy group that is involved in the 1,5-glycocidic linkage in the LPS production. By substituting the 2-hydroxy group of D-arabinose with a phosphonomethyl group, it is theorized that this metabolic pathway can be shut down. Reaction of P(V) 1 with the acetyl protected glyceraldehyde yields the protected straight chain phosphonomethyl D-arabinose 2. Conversion of the acyl silane to the corresponding aldehyde followed by deprotection of the diol yields the desired D-arabinose derivative 3.
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183. MACDONALD "2+2" SYNTHESIS OF A TRANS-DISUBSTITUTED TETRAARYL-PORPHYRIN IN AQUEOUS ANIONIC SURFACTANT. Hiroshi Ogura, Michael D. Carducci, and F. Ann Walker*, Department of Chemistry, University of Arizona, Tucson, AZ 85721.

5,15-Bis(2,3-dimethoxyphenyl)-10,20-bis(4-methylphenyl)porphyrin has been synthesized in 25% yield from 2,3-dimethoxyphenyldipyrromethane and 4-methylbenzaldehyde in an aqueous solution of sodium dodecyl sulfate acidified with HCl. Rearrangement products, often found in a "2+2" synthesis, were undetectable. The porphyrin is obtained as aa- and ab-atropisomers, as demonstrated in our NMR and crystallographic studies. This porphyrin will be used for the synthesis of a picket-fence heme in which the rotation of the axial ligands is hindered.

184. (Note - poster previously listed as # 184 has been withdrawn)

185. MONITORING SILICON NITRIDE PULSED PECVD. BarJean Phillips, Shane D. Steidley, Lisa Lau, and Rene' G. Rodriguez, Idaho State University, Campus Box 8023, Pocatello, ID 83209.

Pulsed PECVD (Plasma Enhanced Chemical Vapor Deposition) of silicon nitride from ammonia, nitrogen, and silane reactant gas mixtures was studied to correlate measurements of reactant gas concentration and temperature with film deposition and thickness, size, and purity for particle deposition. The temperature and reactant gas concentrations as a function of radio frequency pulsewidth were measured using coherent Raman spectroscopy in combination with a fit to theory. Film thickness and particle size distribution were measured with scanning electron microscopy. Possibilities for optimization of radio frequency pulsewidth and power, as well as corresponding reactant concentration and temperature will be explored.

186. PROBING THE SECONDARY STRUCTURE OF THE EQUILIBRIUM UNFOLDED STATES OF CYTOCHROME C. Jonathan O. Speare and Thomas S. Rush, III, Department of Chemistry, The University of Montana, Missoula, MT 59812.

Amide I infrared spectroscopy has been employed to elucidate the differences in secondary structure of horse heart cytochrome c at equilibrium with varying concentrations of deuterated guanidine hydrochloride (DGuHCl). The technique primarily involves subtracting spectral contributions from phosphate buffer, water vapor and denaturant using previously developed procedures. However, with the use of deuterated guanidine hydrochloride, spectra may be recorded for samples with higher concentrations of denaturant than obtained in previous studies. The deuteration shifts the strong C-N stretching mode of guanidine from the middle of the amide I region (1675 cm-1) to the lower end of the region (1600 cm-1), thus allowing a much clearer view of protein amide vibrations. The spectral changes due to the helix structure may then be monitored for equilibrium mixtures ranging from 0.0 to 7.0 M DGuHCl. Initial results show significant reproducible spectral changes occurring at 2.5 M DGuHCl.

187. A MOLECULAR DYNAMICS STUDY OF THE EFFECTS OF SURFACE ORDERING ON THIN n-ALKANE FILMS ADSORBED TO A GRAPHITE SUBSTRATE. Blake A. Purnell and David L. Patrick*, Department of Chemistry, Western Washington University, Bellingham, WA 98225.

Scanning tunneling microscopy has shown that thin fluid films of n-alkanes adsorb to a graphite substrate forming an ordered monolayer. Using molecular dynamics simulations, we examined how this monolayer influences the structure and dynamics of the interfacial fluid film. Simulations were performed on thin (approx. 2.5 nm) n-hexadecane films adsorbed to graphite with and without a crystalline monolayer. Both systems exhibited strong layering, with molecules predominately oriented parallel to the surface. The local orientation order parameter, radius of gyration, diffusion coefficients, and diffusion anisotropy were also examined. Comparison of the two systems reveals that the presence of a crystalline monolayer does not significantly affect the structural and dynamic properties of the interfacial alkane fluid.

188. A STUDY OF THE MICROSCOPIC ORIGINS OF THE SURFACE MEMORY EFFECT AT THE LIQUID CRYSTAL - SOLID INTERFACE. Andrew Brackley, Katherine M. Foland, Joseph D. Mougous, Douglas M. Scott, and David L. Patrick*, Department of Chemistry, Western Washington University, Bellingham, WA 98225.

The surface memory effect (SME) describes the phenomenon in which an initially isotropic surface is rendered anisotropic through contact with an anisotropic medium. At a liquid crystal (LC)-solid interface, the SME leads to imprinting of the director orientation on the surface, which can be used to induce uniform alignment in the bulk LC fluid. The SME is important in LC-based opto-electric devices such as liquid crystal displays. We have studied the SME at a LC-graphite interface using scanning tunneling microscopy and optical microscopy. In films prepared by depositing a LC droplet onto a graphite substrate in an external magnetic field, the SME was found to originate from a uniformly oriented crystalline monolayer. This monolayer produces bulk LC alignment through surface anchoring interactions. To our knowledge, these findings provide the first truly molecular scale understanding of the origins of the SME.

189. DIFUNCTIONAL TETRAPHENYLPORPHYRINS, SYNTHESIS, ISOLATION, AND REACTIVITY. Ira Bennett, William Thompson and Peter J. Pessiki*, Lab 1, The Evergreen State College, Olympia, WA 98505.

Our interest in utilizing porphyrins as components in photomolecular devices required the preparation of some difunctional meso substituted porphyrins. Mixed aniline/benzoic acid (methyl ester) porphyrins have been prepared via a modified version of the Rothemund method. These and similar porphyrins have been linked (via amide bond formation) with other porphyrins and metal chelators. The synthetic details and isolation procedures of these difunctional porphyrins will be given. Progress toward utilizing these porphyrins as metal chelators and as components in self assembling light harvesting solar cells will be discussed.

190. FILM MORPHOLOGY, COMPETITIVE ADSORPTION, AND MOLECULAR MOTION AT A LIQUID-SOLID INTERFACE INVESTIGATED BY SCANNING TUNNELING MICROSCOPY. Joseph D. Mougous, Robert T. Baker, Andrew Brackley and David L. Patrick*. Department of Chemistry, Western Washington University, Bellingham, WA 98225.

We report studies of microscopic film morphology, molecular ordering and domain motion in surface layers deposited from binary mixtures of the organic compounds 4'-octyl-4-biphenylcarbonitrile (8CB) and n-tetracontane. Polycrystalline monolayers deposited from a fluid droplet underwent nanometer-scale phase segregation into pure 8CB and alkane domains. The surface composition was found to vary according to the molar ratio of 8CB and n-tetracontane in solution, with 8CB and tetracontane molar ratios of approx. 600 1 producing mixed monolayers. Alkane adsorption was favored in the early stages of film growth, which was followed by a period of gradual annealing in which 8CB displaced alkane molecules from the surface. This suggests that over a certain range of concentrations, 8CB adsorption is thermodynamically favored, but that n-tetracontane has a significantly larger nucleation rate. Time-resolved scanning tunneling microscopy studies offer molecular-scale insight into the kinetics of domain boundary motion and annealing.

191. RATE OF THERMAL CONVERSION OF CIS- TO TRANS-FATTY ACIDS. Jeanette D. Hanna, Vicky Minderhout*, and David Thorsell, Chemistry Department, Seattle University, Seattle, WA 98122.

Cis-fatty acids occur naturally in oils used for cooking. However, in the process of heating, they may be thermally isomerized to their more thermodynamically stable trans isomer. Since trans-fatty acids have been correlated with heart disease, it is important to know if significant amounts of this isomer might be entering our diet from fried foods. In this experiment, the rate and activation energy of the thermal isomerization of cis-oleic fatty acid (C18:1) to its trans isomer are measured.

192. SEDIMENT CHARACTERIZATION AND SINGLE EXTRACTIONS OF PLUTONIUM CONTAMINATED SEDIMENT. Sarah Herbison, Stacey M. Loyland*, Brian Wilkinson, and Sue B. Clark, Washington State University, Chemistry Department, Pullman, WA 99164-4630.

Sequential extractions are useful for discerning the partitioning of contaminants to specific components of natural sediments. Interpretation of sequential extraction results is facilitated when the sediment is also well characterized. We are studying a lake sediment that was contaminated with 238Pu and 239, 240Pu released from reactor operations. Sediment characterization includes particle size, pH, cation exchange capacity, total metal analysis, organic matter, organically bound iron, amorphous iron, water soluble and exchangeable iron. Single extractions of the sediment have been completed along with sequential extraction results. Our results will be compared, and used to elucidate possible chemical process(es) controlling Pu sorption to a natural sediment.

193. STM ANALYSIS OF ELECTROLYTIC AND ELECTROLESS DEPOSITION OF COPPER METAL ON ANNEALED SILVER FOIL. Max Montano, Erik A. Syrstad, and Kevin E. Johnson*, Chemistry Department, Pacific University; Forest Grove, OR 97116.

The mesoscopic morphology of electrolytic and electroless deposition of copper metal on silver polycrystalline foil was studied. STM images were taken after various quantities of copper were deposited on the silver substrate. With electrolytic deposition, both electrolyte composition and deposition rate were varied to analyze the effects on surface deposition patterns. This research carries implications in metal plating and coating, as well as in corrosion studies.

194. THEORETICAL MODELS OF SUBSTITUENT EFFECT STABILIZATION OF ALUMINUM ANALOGS OF CARBOCATIONS. Timothy L. Sorey, Mari Nishina, and Robert G. Lancaster, Department of Chemistry, Eastern Oregon University, La Grande, OR 97850-2899.

It has been shown in other work in this group that pentavalent aluminum-carbon complexes could exist. A linear free relationship with various substituents is shown to have an effect on the relative stabilities of boron and aluminum analogues of classical versus non-classical carbocations. In some cases, differing substituents can reverse the order of stability when comparing these compounds.

195. THEORETICAL OBSERVATIONS OF ALUMINUM ANALOG MODELS OF CARBOCATIONS. Mari Nishina, Timothy L. Sorey, and Robert G. Lancaster, Department of Chemistry, Eastern Oregon University, La Grande, OR 97850-2899 and Yorke E. Rhodes, New York University, New York, NY 10003.

It is known that boron analogues of both classical and non-classical carbocations can exist. Using Ab Initio calculations, a theoretical study of aluminum analogues of classical and non-classical carbocations has been performed. The relative energies of aluminum models of trivalent carbocations verses pentavalent carbocations have been compared. In some cases, it is predicted that such pentavalent aluminum-carbon complexes could exist.

196. HOMOAROMATIC SEMIBULLVALENES. Richard V. Williams*, John R. Armantrout, Robert W. Tolbert, and W. D. Edwards, Chemistry Department, University of Idaho, Moscow, ID 83844.

Evidence, from experiment and theory, will be presented demonstrating the homoaromatic nature of some semibullvalenes.
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197. A TEST OF THEORY: NICS APPLIED TO DIHYDROPYRENES. Richard V. Williams*, John R. Armantrout, Robert W. Tolbert, and W. D. Edwards, Chemistry Department, University of Idaho, Moscow, ID 83844.

The dihydropyrene nucleus provides an excellent probe for aromaticity. The Nucleus Independent Chemical Shifts (NICS) of a series of dihydropyrenes were calculated and used to construct a scale of aromaticity which was compared with the corresponding experimental scale.
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198. PI-SWITCHES: MULTI-STATE THERMAL AND PHOTOCHEMICAL SWITCHES DERIVED FROM DIMETHYLDIHYDROPYRENES. Reginald H. Mitchell*, Timothy R. Ward, and Yunxia Wang, Department of Chemistry, University of Victoria, Victoria, BC, Canada V8W 3P6.

Elaboration of the dimethyldihydropyrene-cyclophanediene (DMDHP-CPD) photoswitch gives compound I, which has two distinct photoisomers accessible from the ground state I. Results will be presented.
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199. SYNTHESIS AND PHOTOCHEMICAL PROPERTIES OF DIMETHYL-DIHYDROPYRENE SYSTEM. Reginald H. Mitchell,* Yunxia Wang, and Timothy R. Ward, Department of Chemistry, University of Victoria, Victoria, BC, Canada V8W 3P6.

Several annelated dihydropyrenes, e.g., compound I, and II have been made and their multi-state pi-photoswitches have been studied. Our recent results in this area will be presented.
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200. SYNTHESIS AND PHOTOPHYSICAL STUDIES OF DIMETHYLDIHYDRO-PYRENE DERIVATIVES AS POTENTIAL PHOTOSWITCHES. Reginald H. Mitchell*, Cornelia Bohne* and Molina A. Sheepwash, Department of Chemistry, University of Victoria, Victoria, BC, Canada V8W 3P6.

We are interested in the synthesis and photophysical properties of derivatives of dimethyldihydropyrene. Such molecules are photoswitches which may have potential applications in molecular electronic devices.
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201. SYNTHESIS AND CHARACTERIZATION OF DIMETHYLDIHYDROPYRENE-METAL COMPLEXES. Reginald H. Mitchell*, David J. Berg, and Laura-lee Brown, Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, BC, Canada V8W 3P6.

We are interested in the synthesis and characterization of various dimethyldihydropyrene metal complexes. This includes the study of how the metal may be attached to the dimethyldihydropyrene molecule and the affects the metal will have on the dimethyldihydropyrene parent.

202. DEHYDROBENZANNULENE-DIMETHYLDIHYDROPYRENE HYBRIDS: SPECTROSCOPIC PROBES FOR THE STUDY OF WEAKLY DIATROPIC MACROCYCLES. David B. Kimball,a Michael M. Haley,*a Timothy R. Ward,b and Reginald H. Mitchell*b
a Department of Chemistry, University of Oregon, Eugene, OR 97403-1253
b Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, BC, Canada V8W 3V6.

Dimethyldihydropyrene (DDP) has been used as a spectroscopic probe for quantifying the aromaticity of diatropic ring systems that have been fused to the DDP core. To date, however, the only structures studied have been strongly diatropic. We have recently shown that dehydrobenzoannulenes (DBAs) exhibit weak aromaticity. In order to quantify the weak diatropicity of DBA structures, we are assembling DBA/DDP hybrids. We will report our recent synthetic efforts toward the assembly of these unique macrocycles.
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203. SYNTHESIS OF PHENYLCYCLOPROPENES AS PRECURSORS OF METALLANAPHTHALENE AND ITS VALENCE ISOMERS. Eric A. Bercot, Robert D. Gilbertson, and Michael M. Haley*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

(paper copy)

204. SYNTHESIS OF EXPANDED GRAPHDIYNE SUBSTRUCTURES. W. Brad Wan, Stephen C. Brand, and Michael M. Haley*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

(paper copy)

205. STEPWISE ASSEMBLY OF DEHYDROBENZANNULENES (DBAS) WITH UNUSUAL TOPOLOGIES: SYNTHESES, CHARACTERIZATION, AND THEIR CHEMISTRY. Joshua J. Pak and Michael M. Haley*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

(paper copy)

206. DESIGN AND SYNTHESIS OF THREE-DIMENSIONAL CONJUGATED ORGANIC MACROMOLECULES: TOWARD SENSORS, ACTUATORS, AND HELICAL POLYMERS. Michael J. Marsella* and Rodney J. Reid, Department of Chemistry, University of California at Riverside, Riverside, CA 92521.

The design, synthesis, and applications of macromolecules composed of conjugated monomers possessing tetrahedral or pseudo-tetrahedral geometry will be presented. By utilizing a (pseudo)tetrahedral building block, a variety of novel conjugated materials can be prepared, including porous conductors and helical polymers. The porous conductors have been shown to function as sensors for a variety of organic vapors. The helical polymers have been designed to function as actuators. Studies into the physical properties of these high-dimensional materials are ongoing, and will be discussed.

207. DEMONSTRATIONS: COLOR OF CHEMISTRY. Glenn A. Crosby, Department of Chemistry, Washington State University, Pullman, WA 99164.

A variety of laboratory demonstrations will illustrate the visual appeal of chemistry.

208. DEPOSITION OF PHOSPHOR THIN FILMS FOR ELECTROLUMINESCENCE AND CATHODOLUMINESCENCE. Paul H. Holloway, Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611-6400.

Thin films of luminescent materials are desirable for both electroluminescent and field emission flat panel displays. We have studied the synthesis of ZnS:Mn using magnetron sputtering deposition, and of Y2O3:Eu using pulsed laser ablation. The chemistry and structure of the materials are controlled by the deposition parameters in both instances. For sputter deposition, negative ion damage in the deposited film may quench the radiative relaxation mechanism in favor of non-radiative relaxation processes during excitation with an electric field. In the case of pulsed laser ablation, deposition at low power densities and low background oxygen pressures leads to smooth, substoichiometric films with low cathodoluminescent intensities and efficiencies. Deposition at higher oxygen partial pressures (e.g., 300 mTorr) leads to rough films with good stoichiometry and good CL brightness. The effects on the luminescent brightness and efficiency of post-deposition heat treatments with and without "fluxes" will be discussed.

209. THIN FILM ELECTROLUMINESCENT PHOSPHORS FOR FLAT PANEL DISPLAYS. Richard Tuenge, Planar Systems Inc., 1400 NW Compton Drive, Beaverton, OR 97006.

The most efficient electroluminescent (EL) phosphor, ZnS:Mn, has been used in commercial monochrome thin film EL (TFEL) displays for more than ten years. New active matrix and high gray scale EL displays require lower impurity and defect levels in this phosphor film. The defects and impurities in polycrystalline zinc sulfide phosphor films are dependent on the thin film deposition method. Improved luminance stability has been achieved in atomic layer epitaxy (ALE) grown ZnS:Mn films by using chlorine-free precursors. The development of a competitive full-color EL display product has been limited mostly by the performance of the blue phosphor. Improved blue spectral emission was obtained for cerium-activated alkaline earth thiogallates compared with the SrS:Ce phosphor, however, the EL efficiency was not sufficient for product applications. The recent development of an efficient SrS:Cu blue-emitting EL phosphor has improved the performance of full color EL displays. The most recent results for color EL phosphors will be presented in this talk. The status of color passive and active matrix EL displays will
also be reviewed.

210. PHOTO- AND ELECTROLUMINESCENCE OF Sr1-xBaxS:Cu. Ben L. Clark and Douglas A. Keszler, Center for Advanced Materials Research, Oregon State University, Corvallis, OR 97331.

Recently much work has been done on SrS:Cu thin films for use in electroluminescent (EL) devices. In this contribution, synthesis, characterization, and spectroscopic properties of Sr1-xBaxS:Cu with 0<x<1 will be reported. In addition, results of electrooptical and X-ray studies on SrS:Cu EL devices and films prepared by electron-beam deposition will be discussed.

211. SYNTHESIS, CHARACTERIZATION AND SPECTROSCOPIC PROPERTIES OF LixCa2GeO4Fx. Judith L. Kissick* and Douglas A. Keszler, Center for Advanced Materials Research, Oregon State University, Corvallis, OR 97331.

Synthesis, characterization and spectroscopic properties of the new material LixCa2GeO4Fx will be reported. Single Crystal diffraction has been used to establish that LixCa2GeO4Fx crystallizes in the trigonal space group R-3m(h), with unit cell parameters a = 7.3175 Å and c = 42.3372 Å. This, along with chemical and thermal analyses of the material and spectroscopic properties of Nd3+ and Yb3+ doped samples will be discussed.

212. SYNTHESIS, CHARACTERIZATION AND NLO PROPERTIES OF M2Al2(BO3)O (M = Na, K, Rb). Jennifer L. Stone*, Judith L. Kissick and Douglas A. Keszler, Center for Advanced Materials Research, Oregon State University, Corvallis, OR 97331. Gérard Aka and Andrée Kahn-Harrari, Ecole Nationale Supérierure de Chimie de Paris, Laboratoire de Chimie Appliquée de l'Etat Solide, 75321 Paris Cedex 05, France.

The family of noncentrosymmetric orthoborates M2Al2(BO3)3O (M = Na, K, Rb) has been developed. In this contribution, we will describe the relationships between the structures and nonlinear optical properties of the materials. In addition, comparisons will be made to the related family of compounds MAl2(BO3)3O (M = Ca, Sr, Ba.)

213. DEVELOPMENT OF METAL ENCRUSTED PHOSPHONIC ACID MICELLES AS POSSIBLE DRUG DELIVERY VEHICLES. M. R. Helfrich, L. Huffman, M. Ouyang, and C. J. Page*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403-1253.

Micelles and vesicles have been recognized as possible drug delivery agents for over two decades. These systems can be externally functionalized to provide a means of targeted delivery for insoluble tumor fighting agents trapped within the hydrophobic core of the stable aggregate. Our current research is focused on the development of a unique micelle drug delivery system that utilizes a metal crust on its exterior in order to target drug delivery. The characterization of one such system composed of n-dodecanephosphonic acid with and without a variety of Fe3+ salt crusts will be presented as evaluated by transmission electron microscopy (TEM), UV-Vis spectroscopy, static light scattering, and NMR techniques.

214. SELF-ASSEMBLY OF INORGANIC/ORGANIC MULTILAYER THIN FILMS USING COORDINATION CHEMISTRY. Michael A. Ansell, Elizabeth Cogan, Rebecca Hamblin, Geoffrey M. Lowman, Gary L. Succaw and Catherine J. Page*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Layer-by-layer synthesis of novel cobalt, chromium and rhodium-diisocyanide multilayers based on coordination chemistry will be presented, as well as the use of this system in combination with metal-bisphosphonate self-assembly to form 'hybrid' superstructures. Ellipsometry, ATR-FTIR, grazing angle x-ray diffraction, XPS and AFM techniques are used to assess the composition, structure and uniformity of the multilayer assemblies. Our studies indicate that the metal-diisocyanide multilayers are layered, flat films which incorporate both components using in the layer-by-layer synthesis. Layer-by-layer assembly of these films allows the control of thickness, function and proximity of different layers. Potential applications of these films will be discussed

215. INVESTIGATION OF THE THERMAL DECOMPOSITION PRODUCTS OF GRAPHITE INTERCALATION COMPOUNDS BY GC/MS. Nipaka Sukpirom, Xuerong Zhang, Michael M. Lerner*, Department of Chemistry and Center for Advanced Materials Research, Oregon State University, Corvallis, OR 97331-4003.

Acceptor-type graphite intercalation compounds decompose at very low temperature compared with typical salts of the constituent anions. For example, graphite nitrate, graphite bis(trimethylsulfonyl)imide, and graphite perfluorooctanesulfonate, all decompose in the range of 100 - 150 °C, losing the majority of mass from anion degradation. This study will describe an investigation by GC/MS of the volatile gasses generated during decomposition, and discuss these in terms of the decomposition reactions that occur.

216. GRAPHITE INTERCALATION COMPOUNDS PREPARED IN HYDROFLUORIC ACID. Xuerong Zhang and Michael M. Lerner*, Department of Chemistry and Center for Advanced Materials Research, Oregon State University, Corvallis, OR 97331-4003.

The graphite intercalation compounds CxC8F17SO3 · yF and CxN(SO2CF3)2 are readily prepared under ambient conditions in 48 % hydrofluoric acid, using the oxidant K2MnF6. The product compositions are evaluated by mass uptake, TGA, and elemental analysis. PXRD peak position and peak width analyses indicate that the stable product CxC8F17SO3 · yF is obtained after 50 h. (x @ 18, y @ 4) and is comprised of a solid solution of stage 2 and 3. This material can be obtained within 1 h at 50°C. The addition of up to 83 vol. % conc. HNO3 or 17 % fuming H2SO4 produces a stage 2 intercalation compound within hours. 95% of Stage 2 and 5% of stage 3 CxN(SO2CF3)2 (x = 37) is obtained within 15 minutes under ambient condition in HF. The anion orientations for these GICs are evaluated by structural refinement. Larger anions containing -SO2CnF2n+1 substituents can also be intercalated, although the reaction rates are very slow.

217. GALACTOSE OXIDASE: RADICAL REDOX CATALYSIS. Rebekka M. Wachter, Michael P. Montague-Smith, B. Elizabeth Turner, Peter Smalley, and Bruce P. Branchaud*, Department of Chemistry and Institute of Molecular Biology, University of Oregon, Eugene, OR 97403.

This presentation will cover several aspects of radical redox catalysis by galactose oxidase (GOase). GOase has two one-electron redox centers at the active site: a tyrosine radical/tyrosinate and a mononuclear Cu(II)/Cu(I). The use of radical-probing substrates to study GOase reaction mechanisms will be described. Special features of the active site which enhance catalysis by a radical mechanism will be described in the context of a semi-quantitative energy profile that we have constructed for the energetics of the GOase catalytic cycle. From our studies and those of others, a clear picture emerges of how GOase can catalyze one-electron redox processes such as H-atom transfers and electron transfers.

218. SPHINGOMONAS CHLOROPHENOLICA RECRUITS MALEYLACETOACETATE ISOMERASE TO SERVE AS A REDUCTIVE DEHALOGENASE DURING BIODEGRADATION OF PENTACHLOROPHENOL. Shelley D. Copley, Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO 80303-0215.

Xenobiotic compounds are often resistant to biodegradation because microorganisms lack the enzymes necessary to catalyze their breakdown into common metabolites. However, some xenobiotics can be degraded. In these cases, microorganisms have patched together a new metabolic pathway, probably largely by recruitment of pre-existing enzymes to serve functions. We are studying the biodegradation of pentachlorophenol, a xenobiotic that is degradable, in spite of its considerable toxicity and the presence of five chlorine atoms on the aromatic ring. The pathway for degradation begins with the conversion of pentachlorophenol to tetrachlorohydroquinone. Subsequently, tetrachlorohydroquinone undergoes two successive reductive dehalogenation reactions to form 2,6-dichlorohydroquinone. We have recently found that the enzyme that catalyzes this reaction has significant sequence identity to maleylacetoacetate isomerases, and indeed can catalyze the glutathione-dependent isomerization of maleylacetone (a more stable analogue of maleylacetoacetate). The characteristics of the enzyme that allow it to catalyze very different reactions (reductive dehalogenation vs. isomerization of a double bond) using very different substrates (a chlorinated hydroquinone vs. maleylacetoacetate) will be discussed.

219. NEW MODES OF b-LACTAM ANTIBIOTIC FORMATION. Craig A. Townsend, Department of Chemistry, The Johns Hopkins University, Baltimore, MD .

The b-lactam antibiotics are frontline agents in combating bacterial infections in humans. Distinct biochemical solutions to the thermodynamically uphill task of synthesizing these strained molecules in Nature have been discovered. These new assembly and rearrangement processes will be presented.

220. SYNTHESIS OF SUBSTITUTED TETRAHYDROPYRANS VIA PD(II) CATALYZED INTRAMOLECULAR ALKOXYCARBONYLATION. Lonnie A. Robarge, Jian Hong, and James D. White*, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

(paper copy)

221. AN APPROACH TO THE TOTAL SYNTHESIS OF POLYCAVERNOSIDE A. James D. White*, Jian Hong, and Lonnie A. Robarge, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

(paper copy)

222. ATTRACTIVE PI-STACK INTERACTION AS AN EFFICIENT CONTROL ELEMENT FOR ACYCLIC STEREOCONTROL. Jing-Mei Huang, Teck-Peng Loh and Swee-Hock Goh, Department of Chemistry, The National University of Singapore, Lower Kent Ridge Road, Singapore 119260.

A new highly stereochemical control method (> 99% de) of indium-mediated allylation of (R,S)-ketone-ester has been developed during the course of our synthetic studies of natural product dysiherbaine, a result rare for acyclic molecules in the absence of obvious steric interaction or intramolecular chelation. On the contrary, the use of the diastereomer of (R,S)-ketone-ester afforded the product in low selectivity. The reaction of (R,S)-isomer with various allylic bromides and silylenolethers also afforded the products in high selectivities. A systematic investigation will be presented involving physical, chemical and computational studies. Intramolecular pi-stack interaction between the aromatic ring and the ketone group of the (R,S)-ketone-ester has been proven to be the element which contributes to the high selectivity.
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223. A SYNTHESIS OF (±)-GIROLLINE. Michael A. Willis and David A. Horne*, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

(paper copy)

224. IMPROVED SYNTHESIS OF DEBROMOHYMENIALDISINE (DBH). Ana Carolina Barrios S., Kenichi Yakushijin, and David A. Horne*, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

(paper copy)

225. APPROACHES TO THE TOTAL SYNTHESIS OF AGELIFERIN. David A. Horne*, Michael A. Willis, and Kenichi Yakushijin, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

(paper copy)

226. SYNTHESIS OF TWO SUBUNITS OF THE ANTITUMOR AGENT COCHLEAMYCIN A. Lonnie A. Robarge and James D. White*, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

(paper copy)

227. ENANTIOSELECTIVE TOTAL SYNTHESIS OF CRYPTOPHYCIN 1 AND ITS CONGENERS. James D. White*, Jian Hong, and Lonnie A. Robarge, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

(paper copy)

228. PROGRESS TOWARDS THE SYNTHESIS OF AMPA ANALOGS FOR THE TREATMENT OF NEUROLOGICAL DISORDERS. David J. Burhart, Nicholas R. Natale*, Department of Chemistry, University of Idaho, Moscow, ID 83844-2343 and J. Eric Gouaux and G. Chen, Department of Biochemistry, Columbia University, New York, NY 10032.

Analogs designed to bind the important neurotransmitter AMPA (Amino-Methylisoxazole-Propionic Acid) neurotransmitter receptor suspected in a variety of neurological disorders (Stroke, Epilepsy) have been prepared. To date analogs bearing an aromatic ring connected to the C-4 position have been found to lower binding affinity at the AMPA receptor. Lateral metalation methods developed in our laboratories have been employed to prepare C-5 analogs (Tet. Lett. 1998, 8249) , and we are currently examining the Strecker synthesis to prepare AMPA analogs with higher binding affinity. The asymmetric Strecker reaction using Jacobsen's catalyst (J. Am. Chem. Soc. 1998, 120, 5315) is being used to prepare chiral analogs that will help elucidate the role of stereochemistry in substrate binding, and gives good chemical yields. The stereochemistry of this process as applied to isoxazole systems will be discussed.

229. FROM DNA TO MAGNETIC RESONANCE IMAGING. NEW EXPERIMENTS FOR CONNECTING THE LIFE SCIENCES WITH THE CHEMISTRY CURRICULUM. Arthur B. Ellis,* Karen J. Nordell, Joel A. Olson, and Anne-Marie L. Jackelen, Department of Chemistry, University of Wisconsin, Madison, WI 53706; S. Michael Condren, Department of Chemistry, Christian Brothers University, Memphis, TN 38104; and George C. Lisensky, Department of Chemistry, Beloit College, Beloit, WI 53511.

Introductory chemistry courses provide an excellent setting for making connections to ideas and techniques associated with the life sciences. This talk will present a demonstration of the use of optical transforms for illustrating how the architecture of DNA was determined by x-ray diffraction. The principles underlying nuclear magnetic resonance and their extension to magnetic resonance imaging will also be demonstrated. Strategies for enlivening introductory chemistry courses by integrating these topics and experiments into the curriculum will be presented.

230. TEMPERATURE FOR CHEMISTS. Christopher M. King, Pacific Northwest National Lab, Mail Stop P7-25, P.O. Box 999, Richland, WA 99352.

Physicists define temperature as T = (S/E)V, n-1. This relation is found in Gibbs' first publication. The relation may be evaluated with statistical mechanics for simple systems. The "meaning" of temperature is illustrated with a spreadsheet. The ideal gas description of temperature--T is proportional to average kinetic energy--is demonstrated to not be generally valid. Analogies are sometimes made between thermodynamic properties and atomic properties (e.g., hardness). The definition of temperature may be used to consider if the temperature of a single atom is a useful concept.

231. CRIME, CHEMISTRY AND DNA. Andrea J. Scott, Christine M. Pharr,* and Joanna L. Schultz, Chemistry Department, Division of Natural Science, Lewis-Clark State College, Lewiston, ID 83501.

Interdisciplinary approach to chemical and biological analysis was used in this real-life laboratory evaluation of crime evidence. Students in Quantitative Analysis and Genetics were teamed up for 1/3 of their semester lab time to use quantitative skills and DNA sequencing to solve a fictional crime case. Crime scenarios included arson, poisoning and vehicular homicide cases. Gas chromatography and Fourier Transform Infrared Spectroscopy, as well as wet chemistry methods were used by the chemistry students. Biology students refined DNA sequencing protocols to characterize both plant and human DNA sequences. To add authenticity, fingerprint analysis was also included. The students worked independently and conferred as teams in an attempt to solve the crime. The successes and difficulty of this project will be described.

232. EXERCISES BASED ON THE COSMIC BACKGROUND RADIATION DATA. Sydney Bluestone, Department of Chemistry, MS#70, California State University, Fresno, Fresno, CA 93740.

Max Planck's black-body radiation law is the first encounter physical chemistry students have with quantum mechanics. To spark student interest three simple exercises are presented based on the cosmic microwave background radiation data (CBR), the "relic" from the Big Bang primeval explosion. The big-bang model predicted the CBR before being first discovered by Penzias and Wilson in 1965. The CBR data free from atmospheric effects was obtained in 1989 from the Cosmic Background Explorer (COBE) satellite that confirmed all of space was filled with isotropic microwave radiation characterized by a single temperature, which corresponds to the Planck distribution law. From the radiation distribution data students are asked to find the characteristic temperature, the Wien displacement law constant and the Stefen-Boltzmann constant. The COBE satellite radiation distribution data (including weighting factors) are given. To introduce students to the black-body radiation law the original 1900 Planck derivation is presented. n the year 2000 the scientific world will celebrate the centenary anniversary of the historic derivation of Max Planck's black-body radiation equation. The most spectacular application of Planck's law is found in the spectrum of the CBR. Planck had little inkling of the far reaching effects of his important radiation law.

233. MOLECULAR MODELING IN THE INORGANIC CHEMISTRY CURRICULUM. William T. Jordan, Department of Chemistry, Pacific University, Forest Grove, OR 97116.

A set of molecular modeling exercises has been successfully integrated into a one semester inorganic chemistry course. The exercises were created, using CAChe software, to accompany the use of Inorganic Chemistry by Miessler and Tarr, a text based on molecular orbital theory as the unifying concept. Students are assigned at least one, and sometimes two exercises each week. With few exceptions, the assignments are due prior to discussion of the relevant concepts in class. The objective is to actively involve students in building molecules, generating data and computing and interpreting results. As a consequence of their engagement in a scientific process, students become effectively prepared to appreciate the concepts discussed in the classroom. Assignments relate to all components of the course including symmetry, molecular orbital theory, spectroscopy, acid-base chemistry and coordination chemistry

234. USE OF AN ENERGY DISPERSIVE X-RAY (EDX) ANALYSIS SYSTEM IN UNDERGRADUATE LABORATORIES. Barbara A. Balko* and John C. Abele, Departments of Chemistry and Physics, Lewis & Clark College, Portland, OR 97219.

Materials science is an area that is often ignored in traditional chemistry and physics programs at liberal arts colleges, yet it is attractive to students because of its interdisciplinary nature and its relevance to current technology. In 1996, the chemistry and physics departments at Lewis & Clark College installed an energy dispersive X-ray (EDX) analysis system for quantitative microanalysis on the biology department's scanning electron microscope. A National Science Foundation ILI grant (DUE-9552229) assisted in the purchase of the EDX. The EDX system helps us introduce undergraduates to materials science. In this presentation, we describe experiments and research projects that make use of the EDX, most notably the characterization of superconductors and semiconductors synthesized by students.

235. USING ELECTRONIC MAIL IN UNDERGRADUATE CHEMICAL EDUCATION. Morton Z. Hoffman, Department of Chemistry, Boston University, Boston, MA 02215.

Increasingly, in the United States and around the world, undergraduate students at colleges and universities have access to computers and accounts that are linked to local and global networks. The education of students must prepare them for the use of computers in their future professional and personal lives. Electronic mail, which is readily available and simple to use, permits faculty and students to establish connections that are different than those made in the classroom or during office hours. As a result, the interactions are extremely valuable for all parties. The distribution of course material, the downloading of information from the World Wide Web, the communication of ideas and opinions, and the submission of laboratory reports can be rapidly effected. Some examples of the use of e-mail in small and large undergraduate chemistry courses will be presented.

236. CAPSTONE FOR CHEMISTRY MAJORS AT EASTERN OREGON UNIVERSITY. Richard A. Hermens and David G. Camp, II, Department of Chemistry, Eastern Oregon University, La Grande, OR 97850-2899.

The capstone experience for chemistry majors graduating from Eastern Oregon University is composed of several segments. It includes the presentation of two seminars based on searching the chemical literature and a research project under the direction of one of the chemistry faculty or directed by scientists at another institution. It is strongly suggested to the students that the results of their research should be presented in a poster session at a regional or national ACS meeting and/or publication in the Eastern Oregon Science Journal. Each of these contributions to the capstone will be addressed.

237. TEMPERATURE EFFECTS ON THE SOLUBILITY OF CHROMIUM HYDROXIDE AT HIGH pH VALUES. Benjamin Ritherdon and Sue B. Clark, Department of Chemistry, Washington State University, Pullman, WA 99164.

We are investigating the effects of temperature and initial crystallinity on the solubility of Cr3+ in alkaline solutions at elevated temperatures with pH range of 11 to 14. Cr(OH)3.nH2O was prepared by the addition of NaOH to a Cr3+/NaClO4 solution, and an amorphous, dark green solid was produced. Grey, crystalline Cr(OH)3.3H2O was prepared in the same way, except the reactants were cooled to ~5°C. Solids were suspended in solutions of 0.01M NaClO4 at the desired pH and the suspensions were equilibrated at either 25°C or 90°C. Once suspended, all solids became green and non-crystalline. The solutions and solids were sampled periodically. Cr3+ in solution was determined by ICP-AES and solids were characterized by XRD. Changes in dissolved Cr3+ and the solid phases have been monitored for up to 64 days. Our results will be presented along with considerations for processing radioactive waste.

238. IDENTIFICATION OF PRECIPITATES IN A Cr(VI)-CONTAMINATED CONCRETE. Carl D. Palmer, Environmental Science and Resources, Portland State University, Portland, OR 97207.

A sample of Cr(VI)-contaminated concrete from a former hard-chrome plating shop was examined to identify Cr(VI)-precipitates. Scanning electron microscopy revealed the presence of long, thin crystals varying from white to bright yellow. The crystals were typically 10 to 20 times longer than their width. Energy dispersive x-ray spectroscopy indicate that particles are Ca-Al-S-Cr. The morphology, chemistry, and environment of formation suggest that the particles are from the ettringite group. The yellow color is from the substitution of CrO42- for SO42- in the structure so the phase has a general formula of Ca6Al2(SXCr1-XO4)2(OH)12·26H2O. Some of these ettringite crystals appear to be imbedded in a Ca-Si matrix. Identification of the ettringite phase was confirmed through transmission electron microscopy (TEM) using selected area diffraction (SAD) and convergent beam electron diffraction (CBED). Ca(OH)2 (portlandite) and a crystalline Ca-Si phase were also observed with TEM. Cr substitution may also occur in the Ca-Si phase.

239. SYNTHESIS, CHARACTERIZATION, AND THERMODYNAMIC PROPERTIES OF Ca6[Al(OH)6)2(CrO4)3·26H2O, THE CHROMATE ANALOG OF THE MINERAL ETTRINGITE. Robert B. Perkins and Carl D. Palmer, Department of Geology, Portland State University, Portland, OR 97207-0751.

Ca-6[Al(OH)6]2(CrO4)3·26H-2O, the chromate analog of the sulfate mineral ettringite, was synthesized and characterized by XRD, FTIR, TGA, and chemical analyses. The solubility of the synthesized solid was measured at 5 - 75ºC and at pH values from 10.5 to 12.5. The ion activity product for the reaction
Ca6[Al(OH)6]2(CrO4)3·26H2O ¦ 6Ca2+ + 2Al(OH)-4 + CrO2-4 + 4OH- + 26H2O
varies with pH unless a CaCrO4(aq) complex is included in the speciation model. The log Kassoc for this complex, obtained by minimizing the variance in the IAP, is 2.77 ±0.16. The log KSP of Ca6[Al(OH)6]2(CrO4)3·26H2O at 25ºC is -41.4 ±0.3. The temperature dependence of the log KSP is
log KSP = 498.88 - 27497 / T - 181.09 log (T)
DGºr, DHºr, DSºr, and DCºp,r values were calculated from the temperature-dependence of the log KSP. Standard-state formation parameters were determined from these values and partial molal quantities for the constituent ions.

240. WEATHERING OF SCHOEPITE IN SYSTEMS OF DISSOLVED SILICATES. Cindy L. Phelps and Sue B. Clark, Department of Chemistry, Washington State University, Pullman, WA 99164.

The uranyl oxide hydrate schoepite (UO3 . x H-2O) is an initial weathering product of uraninite (UO2+x) and is formed in the corrosion of spent nuclear fuel (SNF). However, thermodynamic data indicate that schoepite is not stable in systems containing dissolved silicate or phosphate. In batch weathering studies conducted in the laboratory, we have observed the formation of uranyl phosphate solids such as autunite (Ca(UO2)2(PO4)2 .10H2O). We are currently studying weathering in systems of dissolved silicates. Although thermodynamic calculations suggest that the uranyl silicate phases such as uranophane (Ca(H3O)2(UO2SiO4)2 . 3H2O) and soddyite ((UO2)2SiO4 . 2H2O) should form, we have not observed them in our systems. Our results will be presented and discussed in light of available thermodynamic data and observations of mineral paragenesis in nature.

241. EFFECT OF TEMPERATURE ON TRIVALENT EUROPIUM COMPLEXATION WITH CHLORIDE, OXALATE, AND ACETATE. Minfang Yeh, Andrew Maddison, and Sue B. Clark, Chemistry Department, Washington State University, P.O. Box 644630, Pullman, WA 99164-4630.

The complexation of the rare earth elements with various organic and inorganic ligands at ambient temperature has been extensively studied, but the temperature dependence of these reactions has received little attention. This information is essential for modeling lanthanide and trivalent actinide speciation in systems such as hydrothermal vents and high level radioactive waste. Using solvent extraction we have measured stability constants for the 1:1 complexes of trivalent europium with chloride, oxalate, and acetate from 10° to 75° C in 1 M NaClO4 at various pH values. The stability constants change significantly from ambient to elevated temperatures. Estimates for the enthalpies of reactions are obtained by extrapolation using the van't Hoff equation. Experimental and modeling results will be presented and discussed.

242. THE AQUEOUS SOLUTION/SOLID SOLUTION PARTITIONING OF CADMIUM TO CALCITE. Andrea Pavlick and James F. Pankow*, Department of Environmental Science and Engineering, Oregon Graduate Institute, Portland, OR 97291-1000.

The calcite/otavite solid solution series is often considered to follow ideal or near ideal mixing behavior due to the similarities between the two end members. However, experimental data for this system are almost always inconsistent with ideal behavior. In some cases, literature values of mixing parameters predict significant miscibility gaps across the solid solution series. In order to better understand the behavior of this system, distribution coefficients for Ca2+ and Cd2+ between aqueous and solid solutions were determined at solid solution compositions near the two end members. A constant composition technique was used which allowed a homogeneous solid solution of known composition to be precipitated onto seed material at a variety of precipitation rates. The identification of equilibrium partitioning behavior allows the calculation of solid phase activity coefficients and estimation of mixing parameters for the system of interest. The data obtained confirm that Cd2+ partitions strongly to calcite forming a solid solution as well as indicating that these two solids are fully miscible but do not mix ideally.

243. UV LASER INTERACTIONS WITH INORGANIC SINGLE CRYSTALS WITH MOLECULAR ANIONS. J. T. Dickinson, C. Bandis, M. Dawes, Y. Kawaguchi, and S. C. Langford, Department of Physics, Washington State University, Pullman, WA 99164-2814.

Single crystal sodium nitrate and brushite (CaHPO4o2H2O) serve as model inorganics containing molecular anions for studies of laser-materials interactions of importance to chemical analysis of inorganics, surface modification, etching, laser machining, as well as thin film growth by laser deposition. In the UV, strong laser coupling can occur in such materials through point defects generated via decomposition of the anion. This can be accomplished either with the laser itself or by simultaneous exposure to electron beams. We present the optical and morphological changes generated by such exposures, the consequences of these modifications on laser-material coupling, and the profound increase in efficiency for using lasers to characterize such materials. We apply time resolved mass spectroscopy and scanning electron microscopy to reveal how crystalline waters of hydration can play a dominant role through diffusion and recrystallization processes, generating high densities of point defects in the near surface region.

244. THE INFLUENCE OF INCREASED CONCENTRATIONS OF NATURAL CONSTITUENTS ON THE ACTION SPECTRUM OF HYDROXYL RADICAL. Brendon Hofsetz and Kenneth Mopper, Department of Chemistry, Washington State University, Pullman, WA 99164-4630, and David J. Kieber*, SUNY College of Environmental Science and Forestry, Chemistry Department, Syracuse, NY 13210.

The hydroxyl (OH) radical is produced photochemically in marine as well as fresh water environments and is important in the chemical cycling of organic compounds in these waters. The determination of OH radical quantum yields has been carried out in Antarctic surface water samples to determine the influence of certain nutrients (NO2- and NO3-) and Dissolved Organic Matter (DOM) on the action spectrum for OH production. OH production is measured using a reliable method that involves reaction with a chemical probe followed by fluorescent detection after HPLC separation. Quantum yields were determined using a monochromatic light source which is used to irradiate the seawater samples. Irradiations are carried out at a number of wavelengths ranging from 280 - 400 nm. The quantum yields at the various wavelengths are then used to determine the action spectrum for OH under different conditions. Results show a wavelength shift for OH production when the different compounds are added to natural seawater.

245. A SENSITIVE AND SELECTIVE DIRECT SPECTROSCOPIC METHOD FOR DETERMINATION OF ATMOSPHERIC ORGANIC PEROXY RADICALS. Dean B. Atkinson, Chemistry Department, Portland State University, Portland, OR 97207.

A novel direct spectroscopic technique is used to measure the concentration of organic peroxy radicals in the nascent air via their structured near-infrared (NIR) absorptions. Peroxy radicals are the secondary oxidation products of hydrocarbons in the atmosphere (following attack by hydroxyl radicals) and are implicated in tropospheric ozone production. A continuous-wave cavity ring-down (CW-CRD) absorption spectrometer with wavelength coverage near 1310 nm has been constructed and tested and offers part per billion absorption sensitivity (cm-1) with 1 MHz spectral resolution. Controlled generation of the ethyl peroxy radical has been accomplished under laboratory conditions, allowing a rovibrationally resolved spectrum to be recorded. Absorption cross sections were determined for the C2H5O2 radical which can be used to provide quantitative determinations of atmospheric concentrations. Spectra of continuously sampled atmospheric air at a variety of total pressures will be presented, illustrating the viability of this direct approach.

246. AC-STM OF SiO2 ON Si. Adam J. Shafer, Amy Szuchmacher, and Tom Engel*, Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195.

In order to more fully understand the growth and resulting nature of insulating SiO2 layers on Si, an alternating current scanning tunneling microscope (ACSTM) has been built. A scanning tunneling microscope has been integrated into a microwave resonant cavity to allow an RF signal to be injected into the tip-sample junction. Local non-linear surface properties cause higher harmonic generation of the injected frequency. The amplitude of the third harmonic signal is then monitored to measure the topography of the surface, as the tip is rastered across the surface. Initial results with MoS2 and hydrogen terminated Si surfaces will be used to illustrate the different information that can be obtained using dc and
ac scanning tunneling microscopy.

247. PHOTO-OXIDATION OF 2-PROPANOL ON TiO2 (100). David W. Brinkley and Thomas Engel, Department. of Chemistry, University of Washington, Seattle, WA 98195.

The use of TiO2 surfaces as photocatalysts for the oxidation of small organics is of great interest in environmental remediation. The thermal and photocatalytic oxidation of small oxygen containing molecules has been investigated on single crystalline TiO2 (100). For the specific case of 2-propanol on the 1x1 phase of TiO2 (100), we found that the total probability for a thermal reaction without molecular oxygen being present is less than .03 for a single collision of an incident molecule with the surface. However, in the presence of molecular oxygen, the thermal reaction probability increases to .08, with the major reaction product being acetone. Photo-oxidation of 2-propanol on the 1x1 phase of TiO2 (100), exhibits the same reactivity and product distribution that is present in the thermal reaction channel. Thus, we conclude that there is no photocatalytic effect for oxidation of 2-propanol associated with the 1x1 phase of TiO2 (100).

248. PICOSECOND PHOTOLUMINESCENCE STUDY OF n-GaAs (100) IN A NONAQUEOUS PHOTOELECTROCHEMICAL CELL. Travis A. Abshere* and Geraldine L. Richmond, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Time resolved photoluminescence (TRPL) and cyclic voltammetry have been used to explore interfacial properties and phenomena of an n-GaAs/Methanol liquid junction solar cell. TRPL decays are taken by illuminating the sample with the 532 nm pulse compressed, focused, frequency doubled output of a mode locked Nd:Yag laser and collecting the 855 nm bandgap luminescence from the GaAs with a cooled multichannel plate PMT. Photoluminescence decays indicate that in deep depletion, these cells undergo anodic photocorrosion resulting in an increase in measured surface recombination velocity and a loss in overall photoluminescence signal. The cell conditions that perpetuate or detract from the corrosion will be discussed along with a comparison with the behavior of aqueous cells studied previously in this lab. Other interesting phenomena observed at this interface will be discussed as time permits.

249. THE EFFECT OF THE CHEMICAL NATURE OF DOPANTS ON THE REDUCTION OF OXYGEN AT a-Fe2O3 SURFACES. Barbara A. Balko* and Kathleen M. Clarkson, Department of Chemistry, Lewis & Clark College, Portland, OR 97219.

The introduction of Fe(II) into predominantly Fe(III) oxides increases the rate of reduction reactions at these surfaces. Thus, it is expected that doping a-Fe2O3 with M(IV) (where M represents a metal) will increase the rate of oxygen reduction on a-Fe2O3 surfaces since a Fe(II) site is created for every M(IV) cation incorporated into the lattice. The addition of the dopants, however, may also introduce energy levels that act as electron traps into the a-Fe2O3 bandgap. We use steady-state polarization methods to compare the reduction of oxygen on a-Fe2O3 oxides doped with Ti(IV), Si(IV), Ce(IV), Sn(IV) and Fe(II). We find significant differences in the behavior of the Ti(IV) and Fe(II) doped oxides, which we believe are due to the formation of electron traps in the case of Ti(IV) and because Fe(II) sites created by direct addition of Fe(II) are different than those due to the presence of the M(IV) cations.

250. MOLECULAR BEAM STUDY OF THE ADSORPTION AND DESORPTION OF HYDROGEN SULFIDE ON Ag(111). Yan Yu* and St. John Dixon-Warren, Department of Chemistry and Program in Materials Science, Washington State University, Pullman, WA 99164-4630.

The adsorption and desorption kinetics of hydrogen sulfide on Ag(111) single crystal has been studied with a combination of molecular beam methods, temperature programmed desorption (TPD), low energy electron diffraction (LEED), and Auger electron spectroscopy (AES). Precursor adsorption kinetics were observed for the adsorption of H2S on the Ag(111) at 80K. The H2S adsorbs reversibly into a weakly bound physisorbed state, which desorbs at ~97K determined by TPD spectra. The adsorption and desorption shows a strong dependence on the substrate treatment. The objective of this work was to deepen our understanding of the surface chemistry of hydrogen sulfide on Ag(111), and to examine the implications of its surface chemistry for the self-assembly of alkanethiols on silver.

251. ALKALI METAL AND CO COADSORPTION AT THE (001) SURFACE OF MgO: A PERIODIC DENSITY FUNCTIONAL LDA AND GGA STUDY. Maciej J. Gutowski*, James A. Snyder, John E. Jaffe, Zijing Lin, and Anthony C. Hess, Materials Resources, Pacific Northwest National Laboratory, Richland, WA 99352.

The co-adsorption of CO with the alkali metals Na and K on the (001) surface of MgO was investigated using a periodic density functional method. We found that the cooperative interaction present among the three constituents of the co-adsorbed system: the MgO slab, the alkali metal monolayer, and the CO monolayer, is very small and the role of MgO is restricted to support the alkali metal monolayer. Our calculations predict weakening of the CO bond due to the presence of the alkali metal monolayer, which is reflected by the elongation of the CO bond and a redshift of the CO stretching frequency in comparison with the corresponding gas phase values. The calculated density of states for the Mg_Na, CO, and Mg_Na_CO systems indicate that the electron transfer from the valence band of the alkali metal to the antibonding pi orbital of CO is the source of the CO bond weakening.

252. ORDERING OF SURFACE WATER MOLECULES IN A POLYETHYLENE OXIDE (PEO) FILM. Elizabeth A. Raymond, Derek E. Gragson, and Geraldine L. Richmond*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Due to their diverse surface properties and applications, polymer thin films are of significant biological interest. However, investigating interactions between a polymer film and an underlying layer of water molecules has previously been very difficult. Our approach to this problem is to use vibrational sum frequency generation (VSFG) to measure the vibrational spectroscopy of surface species. Utilizing the surface selectivity of this technique, we are able to probe the water structure, as polyethylene oxide (PEO) is deposited on the surface. Based on thermodynamic arguments, it has been hypothesized that these surface water molecules become more ordered as a layer of PEO is deposited. Using VSFG we are able to show that ordering of water molecules does occur as a function of the PEO surface concentration.

253. NONLINEAR OPTICAL STUDIES OF ALKYLBENZENESULFONATE ADSORBED AT LIQUID/LIQUID AND AIR/LIQUID INTERFACES. Mark Watry and Geraldine L. Richmond*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Alkylbenzenesulfonates (dodecylbenzenesulfonate(DBS) in particular) are widely used as emulsifiers in detergents, soaps, paints, and other oil in water systems. The focus of the studies to be described is to measure the molecular structure of DBS adsorbed at the CCl4/H2O and Air/H2O interfaces using surface tension and a combination of nonlinear optical methods. Vibrational sum-frequency spectroscopy (VSFS) has been employed to investigate changes in the vibrational spectrum of DBS and H2O as the number density and conformation of the molecules change at the interface. Second harmonic generation has been employed to complement the VSFS by examining changes in the molecular orientation of DBS. These studies have provided the first molecular level picture of the orientation and conformation of this important surfactant at these interfaces.

254. PAPER-MAKING POTENTIAL OF WASHINGTON WHEAT STRAW. Roberta S. Jacobs1, W. L. Pan2, and W. T. McKean1, 1Paper Science and Engineering, University of Washington, Seattle, WA 98195-2100, 2Soil Science, Washington State University, Pullman, WA 99164-6420.

Current environmental and social pressures are limiting wood harvest from U. S. public forest land. As a byproduct of the cereal grain industry, wheat straw may also be used for papermaking. However heterogeneity has been found within this potential raw material. The chemical composition and fiber properties of the wheat straw vary with growing condition, wheat cultivar, and with the part of the plant processed. These differences in chemical composition may affect both pulping yield and the non-process elements entering the pulp mill. The taller plants had higher average fiber lengths which correlate with pulp strength properties. This local range of growing conditions, cultivars, and the abundance of straw will give papermakers the prospect of selectively collecting the straw best suited for their process and product. With these opportunities, the future of wheat straw as a papermaking raw material looks promising.

255. MODIFICATION OF NON-CELLULOSIC POLYSACCHARIDES DURING THERMOMECHANICAL PULPING AND PEROXIDE BLEACHING OF WESTERN HEMLOCK AND LODGEPOLE PINE. Andy J. Hanneman, B. F. Hrutfiord, and W. T. McKean, College of Forest Resources, University of Washington, Seattle, WA 98195.

The highly concentrated colloidal fraction of recycled bleach plant dilution water from a thermomechanical pulp mill was enriched with pectins and arabinogalactans. Dilution of unbleached pulp from the same mill at pH 5.2 released arabinogalactans, while dilution of bleached pulp at pH 7.0 released pectins. Bleach plant dilution water colloids also contained 10% wood resin and 13% inorganic material. The presence of polyvalent cations, including aluminum, in the inorganic fraction may be attributed to dilution water recycling and to chelation of metals by the galacturonic acid moieties of pectin. Uncontrolled buildup of polyvalent cations during water recycling can be detrimental for pulp bleaching. Co-release of resin and pectin during alkaline peroxide bleaching may also impact the chemistry of alum-induced pulp self-sizing.

256. THE EFFECT OF FORMULATION AND PROCESSING VARIABLES ON THE HOT PRESS EMISSION OF FORMALDEHYDE FROM PHENOL/FORMALDEHYDE SATURATING RESINS. Scott W. Briggs* and Douglas E. Honeyford, Simpson Select Overlays, P.O. Box 17307, Portland, OR 97217.

The important formulation and processing parameters to limit the amount of free formaldehyde released from industrial paper overlays during hot press application are identified. Factors including mole ratio of reactants and catalyst and reaction temperature are discussed in reference to the synthesis of technical phenol/formaldehyde saturating resins

257. REAGENT CHEMICALS: WHERE THEY COME FROM. Vaceli M. Baghdanov, TCI America, 9211 N. Harborgate Street, Portland, OR 97203.

Reagent chemicals are a fact of life for any chemist. Where they come from is often unknown to the user. This presentation will outline the general process at TCI America that is in involved in putting a reagent chemical on the market.

258. CHEMOPREVENTION: CAN THE CHEMIST PLAY A ROLE? William E. Garwood, Rowan University, Glassboro, NJ 08028.

The definition of chemoprevention as "the systemic use of specific natural or synthetic chemical agents to reverse or suppress the progression of a premalignancy to invasive cancer" (underline mine) suggests that a chemist can indeed play a role in the war on cancer. An example of such effort involving the requirements of an idea, motivation, in vitro and in vivo studies, funding, bridging the gap to the medical profession, and finally adjusting to the long-range nature of the effort, will be discussed.

259. HISTORY OF CHEMISTRY IN PORTLAND. Alfred S. Levinson., Department of Chemistry, Portland State University, Portland, OR 97207-0751.

Significant past chemical historical events in Portland including the development of chemical education will be discussed.

260. HISTORY OF THE ACS PORTLAND SECTION. Chester Schink, 3943 SE Cooper St., Portland, OR 97202.

Following World War II there were a significant number of chemists and chemically related workers in the Portland area, but they were mostly working singly in small businesses. The academic nature of the ACS meetings and location in Corvallis and Eugene failed to meet the needs of these people. This led to the formation of the Portland Industrial Chemists Association (PICA) in 1951. This caused renewed interest in the ACS and the formation of the Portland Section. Both PICA and the ACS are active at this time.
The formation of Tektronix in 1946 started the flow of high tech industries in the Beaverton area and the subsequent growth of "Silicon Forest". The early growth of Tektronix will be discussed.

261. THE RISE, FALL, AND REINCARNATION OF CHEMISTRY AT OGI. Thomas M. Loehr, Department of Biochemistry and Molecular Biology, Oregon Graduate Institute of Science and Technology, Portland, OR 97291-1000.

The Oregon Graduate Institute was founded in the early 1960s through the efforts of Governor Mark Hatfield to specifically address the lack of graduate-level science and technology research and education in the Portland metropolitan area. The "founding faculty" of 20 young scientists included 13 chemists and 5 physicists. The new institution was unique in its role as a "micro-university," chartered by the State of Oregon to award masters- and doctorate-degrees, but without having an undergraduate body. Chemistry and related fields were major areas of research, and the early faculty at OGI were equipped with state-of-the-art instrumentation. The changes in federal research funding in the 1970s and '80s supported a shift in research emphasis away from traditional chemistry toward biological sciences, biochemistry, and molecular biology. The "History of Chemistry at OGI" will be presented by one of its founding faculty who has been an active research scientist and educator for over 30 years. The presentation will form part of two panels meeting to discuss the "History of Chemistry in the Portland Area." One will focus on industrial chemistry and the second on its academic institutions.

262. CHEMICAL RESEARCH ON WOOD CHEMICALS AT THE CROWN ZELLERBACH RESEARCH LABORATORY. Wilbur Shilling, 10615 S. W. Highland Drive, Tigard, OR 97224 and David Goheen, 2193 N. E. 3rd Ave., Camas, WA 98607.

Research on wood chemistry and the industrial chemicals that have been manufactured will be discussed by the authors as an introduction to the a panel discussion will be presented. The early research on deriving dimethyl sulfide, dimethyl sulfoxide, dimethyl sulfone, and methyl mercaptan and other important industrial chemicals from wood pulping liquors will be discussed.

263. PANEL DISCUSSION. Wilbur Shilling, 10615 S. W. Highland Drive, Tigard, OR 97224 and Marsh Cronyn, Department of Chemistry, Reed College, Portland, OR 97202.

A panel will present an anecdotal account of major wood products research at the Crown Zellerbach Research Laboratory. Coverage will include preparation, manufacture, and uses of chemicals from wood: dimethyl sulfide, dimethyl sulfoxide, dimethyl sulfone, methyl mercaptan and dimethyldisulfide, thiophenols, methylenedioxybenzene, levulinic acid, conidendrol, and thujaplicin; and uses for spent pulping liquors (ligninsulfonates, lignin hydrogenolysis), plywood overlay and others. The panel will be selected from the following authors of the original research, based on their availability: R. Bailey, J. Barton, M. Cisney, H. Clausen, R. Damon, C. Hoyt, D. Goheen, H. Lackey, W. MacGregor, W. Fowells, and W. Shilling.

264. CLOSURE OF THE CROWN ZELLERBACH RESEARCH FACILITY. James E. Walther, 19610 NW 30th Ave, Ridgefield, WA 96642.

Panel talk will outline the series of events that caused the Crown Zellerbach Research Facility at Camas with employment of over 200 technical scientists to be totally eliminated over a 25 year period with final closure in 1995. Major events included the Corporate fight for life and the eventual acquisition of Crown Zellerbach by Sir James Goldsmith and sale to the James River Corporation in 1986. Merger of James River and Fort Howard Corporation in 1997-8 led to the final elimination of the research laboratory.

265. QUILTING TOGETHER A PROFESSIONAL LIFE IN SCIENCE. Geraldine L. Richmond, Department of Chemistry, University of Oregon, Eugene, OR 97403.

One of the most delightful and unexpected aspects of my experience as a scientist has been in the discovery of the wonderful community of women scientists that I have met and worked with over the years. These women's lives that I see around me are far more colorful, complex, demanding, and interesting than the monolithic image that I had of a female scientist when I decided to enter a scientific career. As I reflect on the lives of these women, I am drawn by the analogy between the characteristics and experiences of these women scientists and the richness and complexity of a handmade quilt; a quilt requiring hard work and dedication but also one which, when completed, provides the worker with much self satisfaction and a true feeling of accomplishment. This analogy for me is so thought-provoking that I thought it might be fun to explore it further in this piece, using quilts made by women from around the country for illustration. In this presentation I will show slides of a series of quilts that illustrate my thoughts in this area. Although the presentation was conceived with women scientists in mind, there are common threads in this presentation that go beyond women scientists and reach to both men and women of other disciplines.

266. PHASE EQUILIBRIA AND CRYSTAL-CHEMICAL STUDIES OF OXIDE SYSTEMS OF INTEREST FOR WIRELESS COMMUNICATIONS. Terrell A. Vanderah, Ceramics Division, National Institute of Standards and Technology, Ceramics Division, Gaithersburg, MD 20899.

Every modern commercial wireless communication and detection system incorporates dielectric oxide ceramics with unique electrical properties as critical elements. These materials are used to fabricate a variety of components that store, filter, and/or transfer electromagnetic energy with minimal loss (e.g., resonators, bandpass filters, circulators). The required properties include high dielectric constants, high Q factors (i.e., low dielectric losses), and zero or low temperature coefficient and frequency dependence of the dielectric properties. Accurate phase diagram information is useful because all practical ceramics are processed as controlled mixtures to achieve temperature stability of the dielectric properties. Oxides currently in use were discovered empirically, with scant knowledge of fundamental chemistry-structure-property relations. Chemical systems of interest include complex oxides featuring (Ti,M)-O and (Nb,M)-O octahedral matrices with larger A-cations such as Ba2+, Sr2+, or Ca2+. The results of recent experimental studies of ternary systems will be presented. Trends in compound formation, crystal chemistry, and dielectric properties will be described.

267. SYNTHESIS AND HYDRATION OF ZrW2-xMoxO8 PHASES. Niangao Duan, U. Kameswari, and Arthur W. Sleight*, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

Cubic phases of the type ZrW2-xMoxO8 show strong negative thermal expansion over broad temperature ranges. Synthesis of these phases is complicated by their metastability. A new combustion synthesis will be described. Hydration of these phases results in a pronounced decrease in unit cell volume. For ZrW2O8, a = 9.16 Å; for ZrW2O8·H2O, a = 8.84 Å. This contraction is presumably an indication of strong hydrogen bonding between the network and the inserted water.

268. NEGATIVE THERMAL EXPANSION IN AOMO4 COMPOUNDS. Tammy G. Amos and Arthur W. Sleight*, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

We are investigating the thermal expansion properties of AOMO4 compounds with structures based on corner-sharing AO6 octahedra and MO4 tetrahedra. In tetragonal NbOPO4 negative thermal expansion behavior is observed above a phase transition at about 200°C. The other AOMO4 compounds under study have a different connectivity of the octahedra and tetrahedra. The symmetry is orthorhombic or monoclinic. Typically there is a monoclinic-to-orthorhombic phase transition occurring with increasing temperature. Negative thermal expansion behavior is found in the orthorhombic structure, but not in the monoclinic structure. In addition to NbOPO44, compounds under study include TaOPO4, TaOVO4, VOPO4, SbOPO4, and MoOPO4.

269. PROBING RELATIVE ACIDITIES IN SOLID-ACID-LAYERED PEROVSKITES. Helen K. White, Joshua T. Schmidt, Leo S. MacDonald, and Margret J. Geselbracht*, Department of Chemistry, Reed College, 3203 SE Woodstock Blvd., Portland, OR 97202.
The relative acidity of solid acid layered perovskites such as HCa2Nb3O10 can be tuned by substitutional doping on the transition metal site. Previous work in the literature has involved doping Ti4+, Fe3+, or Al3+ on the Nb5+ site. In all of these cases, the result was a weaker solid acid relative to the pure niobium parent compound. We have been investigating a new series of tantalum-doped layered perovskite solid acids, HCa2Nb3-xTaxO10 (0 < x < 3). To characterize the relative acidities of these compounds, we have carried out intercalation reactions across the series with n--hexylamine and pyridine. Intercalation products were characterized by X-ray powder diffraction and thermal gravimetric analysis. From this data, we conclude that materials with high tantalum contents are weaker acids than the parent compound HCa2Nb3O10.

270. CONTROLLED SYNTHESIS OF A BINARY SKUTTERUDITE USING MODULATED ELEMENTAL REACTANTS. Mark B. Johnson, Joshua R. Williams, and David C. Johnson*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403.

The synthesis of the metastable binary compound FeSb3 has been studied as a function of varying two parameters - elemental layer thickness and overall composition in elementally modulated multilayer reactants. Upon low temperature annealing of samples with an elemental layer thickness below a critical value, an amorphous iron antimony alloy forms. Higher temperature annealing of this alloy results in nucleation and growth of crystalline binary iron antimonides. The identity of the compound nucleated depends on overall composition. Near a 1:2 composition, FeSb2 forms. For samples near a 1:3 ratio of Fe:Sb, the metastable compound FeSb3 was obtained. We have measured the nucleation energies as a function of composition within the ultrathin multilayer reaction pathway.

271. THE EFFECT OF FILLING ATOMS ON THE LATTICE THERMAL CONDUCTIVITY OF NEW SKUTTERUDITE COMPOUNDS. Heike Sellinschegg, George S. Nolas** and David C. Johnson*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403; ** Marlow Industries, 10451 Vista Park Road, Dallas, TX 75238.

Filled skutterudite antimonides are very promising candidates for new thermoelectric materials. New, metastable ternary crystalline compounds with the skutterudite crystal structure have been synthesized using the multilayer precursor method. Elementally modulated elemental reactants interdiffuse at low temperatures to form an amorphous intermediate which then is annealed to crystallize exothermically to form the desired structure. Bulk samples with the formula MxCo4Sb12, where M = La, Lu, Gd were prepared. The 'filler atom' M is believed to rattle in the voids of the structure and to interact with a broad spectrum of lattice phonons reducing their mean free paths considerably. In this study we examine the effect of varying the filler atom as well as the degree of void filling on the measured lattice thermal conductivity

272. LOW-DIMENSIONAL ANIONIC NETWORKS IN TERNARY PNICTIDES. Arthur Mar, Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2.

Ternary pnictides display a wide variety of structures characterized by the presence of low-dimensional networks of homoatomic pnicogen-pnicogen bonds. These networks range from one-dimensional zigzag chains (in Ba2Sn3Sb6), to ribbons of greater widths (in Ba0.8Hf12As17.7), to two-dimensional square nets (in LaIn0.8Sb2). Weakening or distortion of these anionic networks occurs to accommodate electron density transferred from the electropositive components of the ternary compound. A number of structures characterized in our group are presented to illustrate this idea.

273. NEW LAYERED TERNARY RARE-EARTH INDIUM ANTIMONIDES, REInxSb2 (RE = La-Nd) AND THE STRUCTURE OF LaIn0.8Sb2. Michael J. Ferguson, Robert E. Ellenwood, and Arthur Mar,* Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2.

A new series of ternary rare-earth indium antimonides, REInxSb2 (RE = La-Nd) has been synthesized through reaction of the elements at 950ºC. The crystal structure of LaIn0.8Sb2 has been determined by single-crystal X-ray diffraction methods. It consists of nearly square nets of Sb atoms alternately stacking with layers of composition [In0.8Sb], separated by the La cations. Structural relationships are drawn between this compound and other layered ternary antimonides. The bonding is analyzed by extended Hückel band structure calculations, which predict weakly metallic behavior.

274. THE EFFECTS OF CERIUM FILLING ON COBALT TRIANTIMONIDE SKUTTERUDITES. Arwyn L. E. Smalley, Heike Sellinschegg, Joshua R. Williams, and David C. Johnson*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403.

Thermoelectrics have recently gained more attention since new, and potentially more efficient, thermoelectric materials have been discovered or created. The "quality" of a thermoelectric, called the figure of merit, is determined using the thermal conductivity, the electrical conductivity, and the Seebeck coefficient. CoSb3 is a skutterudite, a material with a cubic crystalline structure. The CoSb3 crystal has large voids surrounded by "cages" of the CoSb3 compound. While CoSb3 is not a good thermoelectric material itself, its figure of merit is significantly improved upon the filling of rare earth atoms into the voids in the crystalline structure. We are filling the voids of CoSb3 with Ce using a novel technique, and are examining the effects of this addition on the figure of merit through analysis of Seebeck coefficient and conductivity measurements.

275. PLATELET ACTIVATING FACTOR ACETYL-HYDROLASE: TO BE OR NOT TO BE AN INTERFACIAL ENZYME. Jung-Hyun Min1, Cheryl Wilder2, Leland Paul2, and Michael H. Gelb1*, 1Departments of Chemistry and Biochemistry, University of Washington, Seattle, WA 98195 and 2ICOS Corporation, Bothell, WA 98012.

Platelet activating factor acetyl-hydrolase (PAF-AH) is an enzyme bound to serum lipoproteins that degrades platelet activating factor (PAF) as a way to terminate the proinflammatory properties of PAF. The enzyme shows high activity on PAF which contains a short sn-2 fatty acyl chain (acetyl), but does not hydrolyze phospholipids with long sn-2 fatty acyl chains. The enzyme also works well on phospholipids that have oxidatively truncated sn-2 fatty acyl chains. We have shown that PAF-AH binds tightly to vesicles of zwitterionic phosphatidylcholine as well as anionic phosphatidylmethanol vesicles. Vesicle bound enzyme displays high catalytic activity toward PAF and PAF analogs. We addressed the question of whether enzyme must access its substrate from the interface or from the aqueous phase. Answering this question is non-trivial because any steady-state velocity equation that depends on the aqueous phase concentration of substrate can be written in terms of the membrane phase concentration and the aqueous-to-membrane partition equilibrium constant. Thus a novel non-steady-state approach will be presented that distinguishes the two mechanisms. The results readily explain the substrate specificity of PAF-AH.

276. FORMATION AND FUNCTION OF PSEUDOURIDINE IN RNA. David A. Horne, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

The rearrangement of uridine residues to pseudouridine in RNA is catalyzed by pseudouridine synthases. Both substrate recognition and mechanistic aspects of pseudouridine formation for two classes of pseudouridine synthases will be presented. The role of pseudouridine in peptidyl transfer processes will also be addressed.
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277. NEW CHEMICAL APPROACHES TO TRACING CELLULAR SIGNAL TRANSDUCTION CASCADES. Kevan M. Shokat*, Kavita Shah, Yi Liu, Feng Yang, and Anthony Bishop, Department of Chemistry, Princeton University, Princeton, NJ 08544.

My laboratory has developed several new chemical approaches for deciphering cellular protein kinase cascades. Protein kinases are involved in oncogenesis, learning, memory, regulation of cell cycle, cell movement and morphology, vesicle release of neurotransmitters, and almost every cellular function known. Although particular protein kinases are known to be associated with particular pathways, the precise molecular role of each kinase is not known because of the difficulty in identifying a given kinase's direct substrates. The difficulty lies in the fact that protein kinases comprise the largest family of proteins in the genome (= 2% in the human). Furthermore gene knockouts of kinases often have no phenotype due to compensation by closely related kinases. New chemical approaches which address these problems will be discussed.

278. THE ADDITION OF SF5X (X = Cl, Br) TO ACRYLATES - PATHWAY TO NOVEL PENTAFLUOROTHIO(SF5) PROPIONATES. Rolf Winter and Gary L. Gard*, Department of Chemistry, Portland State University, Portland, OR 97207-0751.

A significant pathway involving SF5X addition to acrylates results in the formation of pentafluorothio (SF5) propionates which in turn are used in preparing novel three-carbon aliphatic SF5 compounds. The use of three-carbon aliphatic SF5 compounds in preparing long-chain and polymeric derivatives is under study.

279. RECENT ADVANCES IN ORGANOSULFUR FLUORINE CHEMISTRY. THE CHEMISTRY OF SF5CF2CF2I - PATHWAYS TO SF5-FLUOROALKYL/SF5-AROMATIC DERIVATIVES. Gary L. Gard*, Paul Nixon, Anna-Maria Hodges, Robin Terjeson, and Rolf Winter, Chemistry Department, Portland State University, Portland, OR 97207-0751.

In order to prepare a number of potentially important SF5-organofluoro derivatives, the chemistry of SF5CF2CF2I was studied. As a synthon, SF5CF2CF2I (like CF3I) was found to be effective and produced a number of important SF5-fluoroalkyl/SF5-aromatic compounds. In addition, new polymeric thin-film coatings have been developed and characterized.

280. INVESTIGATION OF MOLECULAR RECOGNITION EVENTS WITH MESOMORPHIC HOSTS: BARBITAL BINDING IN ISOTROPIC AND CHOLESTERIC LIQUID CRYSTAL ENVIRONMENTS. R. Carlisle Chambers*, Anna E. McInturf, Tauni M. Clark, and Bonnie C. Leasure, Department of Chemistry, George Fox University, Newberg, OR 97132.

This research describes the synthesis and characterization of macromolecules, which exhibit both molecular recognition and mesomorphic properties. The overall goal is to examine host-guest binding events in cholesteric liquid crystal systems. The mesogens prepared here serve as hosts for barbiturate guests and they have been modified by covalently attaching cholesteryl moieties. The isotropic binding events and stabilities of several mesogens were analyzed in the isotropic phase using barbital and phenobarbital guests. The association constants obtained by UV and NMR titration methods are reported. We also report preliminary efforts to prepare cholesteric liquid crystal displays that include the modified mesogens. Our attempts to evaluate guest binding in the mesomorphic environment is also discussed.

281. SYNTHESIS OF NOVEL CROSS-CONJUGATED RADIALENES. Eric E. Edstrom* and Troy M. Voelker, Department of Chemistry, University of Montana, Missoula, MT 59812.

[graphic will be taken from paper]
Key methodologies for synthesis of cross-conjugated radialenes as typified by the [18] annulene (1) will be presented. Direct palladium catalyzed cross-coupling between vinyl triflate and terminal ynone derivatives, in an iterative process, provides an expedient route to the formation of such compounds. The use of a sterically hindered base plays a key role in the success of these cross-coupling reactions.

282. THE USE OF DIPYRROMETHENE LIGANDS IN SELF-ASSEMBLY. Alison Thompson, Steven J. Rettig and David Dolphin*, Department of Chemistry, University of British Columbia, Vancouver, BC, Canada.

The dipyrromethene unit 1 is a fully conjugated flat moiety, constructed from pyrrolic precursors. It has long been utilized in the field of porphyrin chemistry, but its use within supramolecular chemistry is now being realized. Ligands consisting of linked dipyrromethene units have been prepared and used in complexation reactions, to generate novel uncharged supramolecular nano-structures via self-assembly. The use of molecular modeling to provide an insight into the factors influencing ligand design and the self-assembly process will also be discussed.
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283. PEPTIDE BOND FORMATION VIA CATALYTIC ANTIBODIES: DESIGN AND SYNTHESIS OF A SECOND-GENERATION HAPTEN. Barton W. Phillips, Amos B. Smith, III, Seiji Iwama, and Jason Witherington, Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104.

(paper copy)

284. TWO NEW MALYNGAMIDES FROM A MADAGASCAN LYNGBYA MAJUSCULA. Kenneth E. Milligan, Brian L. Marquez, R. Thomas Williamson, and William H. Gerwick*, Oregon State University, College of Pharmacy, Corvallis, OR 97331.

The lipid extract of a Madagascan Lyngbya majuscula has yielded malyngamides O and P, both amides of 7-methoxytetradec-4 enoic acid. Malyngamides O and P are related to malyngamides A and B due to the presence of a pyrrolidone ring system in all four compounds. The isolation of these metabolites was carried out by liquid chromatography with final purification through repetitive reversed phase HPLC. Structure elucidation was accomplished by 1D and 2D NMR spectroscopic characterization of the natural products and comparisons with malyngamide A.

285. USE OF 1D AND 2D 1H-13C HSQMBC FOR THE ANALYSIS OF LONG RANGE COUPLING CONSTANTS AND THEIR APPLICATION TO THE STRUCTURE ELUCIDATION OF NATURAL PRODUCTS. Brian L. Marquez, R. Thomas Williamson, and William H. Gerwick*, Oregon State University, College of Pharmacy, Corvallis, OR 97331.

Long range heteronuclear coupling constants provide valuable information for the stereochemical and conformational analysis of biologically active natural products. However, a sensitive and convenient method for their measurement has not been generally available. As a result, application of these coupling constants has been consistently overlooked. Here we present two new experiments to expedite the measurement of long range heteronuclear coupling constants and demonstrate their use to facilitate the characterization of naturally occurring compounds. These experiments provide pure absorption lineshapes in F2 and eliminate complications arising from the evolution of 1H-1H couplings during the long delay necessary for long range heteronuclear couplings to evolve.

286. X-RAY AND NMR STEREOCHEMICAL STUDIES ON THE 2,3-DICHLORO-2,3-DIHYDROTHIOPHENE S-OXIDE PRODUCTS FORMED FROM THIENO[2,3-B]PYRIDINE AND BENZO[B]THIOPHENE REACTANTS. Leroy H. Klemm, Timothy J. R. Weakley, and Myungok Yoon, Department of Chemistry, University of Oregon, Eugene, OR 97403-1253.

paper copy

287. TAKING THE SIGH OUT OF SCIENCE: TEACHING CHEMISTRY TO THE NON-SCIENCE MAJOR. Geraldine L. Richmond, Department of Chemistry, University of Oregon, Eugene OR 97403.

One of the more challenging courses to teach in the undergraduate chemistry curriculum is one which teaches science literacy, and specifically chemistry literacy to the student who is a humanities or social science major. These students are often not particularly motivated to take an introductory chemistry course and are often science-phobic. However, it is exactly these students whom we need to engage in a dialogue about scientific issues so that they can make informed decisions about the technological world around them. The challenge is to develop a course that is engaging to these students while not compromising high academic standards and the desire for a high level of retention of the material once they leave the course. In this talk I will discuss techniques that I have used to teach courses of this nature.

288. A MATERIALS LIFE: FINDING RELEVANCY FOR THE NON-SCIENCE MAJOR. Kristi L. Miller and Carl C. Wamser*, Center for Science Education and Department of Chemistry, Portland State University, Portland, OR 97207.

The Science Cornerstone Project was implemented two years ago at Portland State University to design and develop a set of courses specifically for those students not majoring in science. These courses work to foster an appreciation of science and show how it applies to the student's six life roles: individual, learner, citizen, consumer, producer, and family member. When students can apply science to their lives and see its impact, it becomes more meaningful and relevant. As one of these courses, the "Materials for the 21st Century" class strives to accommodate diverse learning styles through a wide range of activities so that students will be able to successfully access and assess scientific information as lifelong learners of science. To achieve this, a combination of activities such as group work, class discussions, video presentations, text readings, lecture, and hands-on labs have been implemented for each of the major content areas. To show how science applies to the learner, citizen and consumer life roles, we have incorporated community involvement into the curriculum. We have implemented this by visiting several materials manufacturing plants and hosting materials scientists in the community to speak to the class. This allows students not only to understand the role of scientists, but to see the effect of materials manufacturing in their community, and ultimately how it applies to their lives.

289. HAS THE TIME ARRIVED FOR A NEW TYPE OF DEGREE FOR HIGH SCHOOL TEACHERS OF SCIENCE? Glenn A. Crosby, Department of Chemistry, Washington State University, Pullman, WA 99164-4630.

Both anecdotal and statistical evidence tell us that the current core of science teachers in high schools, particularly those teaching physics and chemistry, are leaving the system. Evidence from the schools and universities also confirms that they will be replaced by teachers who have been primarily educated in the biological sciences. Thus, the teaching of the physical science will fall to those who have minimal backgrounds in quantitative subjects, or possibly to those with virtually no education in the basic physical sciences at all. The implications for the Nation's schools, and for the economy, are profound. Fewer and fewer students will arrive on the college campuses ready or willing to major in the physical sciences and engineering and the trend toward more foreign nationals in our graduate programs will be accelerated. It is the conviction of the author that the decline of majors in the quantitative sciences who plan to enter the teaching profession can only be reversed by a revolutionary change in the curricula at colleges and universities. The author will propose a new secondary science education major, centered in the chemical sciences, supported by physics and computer science, and incorporating modern molecular biology. The need for such an educational shift, the problems implementing it, and the benefits to be derived from such an innovation will be presented.

290. INVOLVING K-12 IN-SERVICE TEACHERS IN THE SCIENCE PREPARATION OF FUTURE TEACHERS. Anna G. Cavinato* and S. A. Bottoms, Department of Chemistry, Eastern Oregon University, La Grande, OR 97850.

The Oregon Collaborative for Excellence in the Preparation of Teachers (OCEPT) is a statewide collaboration of institutions of higher education dedicated to strengthening the math and science preparation of future teachers and increase the state's teacher workforce diversity. With support from OCEPT we have developed and implemented a new Introductory Science sequence which is designed to teach prospective teachers how to teach science. The sequence is team-taught by a chemistry faculty who insures appropriate science content and methodologies and by a K-12 teacher in residence who brings classroom perspective and experience. The first eight weeks of the curriculum are dedicated to learn about science and the scientific process while the final two weeks take the students into the elementary classrooms. This insures further involvment of other K-6 teachers who host the science students and mentor them in the preparation of their lessons.

291. LEARNING ABOUT ENVIRONMENTAL CHEMISTRY IN A COURSE EMPHASIZING STUDENT PRESENTATIONS. Thomas G. Dunne, Department of Chemistry, Reed College, Portland, OR 97202-8199.

A new environmental chemistry seminar course will be described as to clientele, subject matter, and teaching modes. This course is a work in progress, so my presentation will be structured, and timed to permit as much audience participation as possible.

292. COMPUTERS IN THE FIRST YEAR GENERAL CHEMISTRY LABORATORY: AN OVERVIEW. William J. Randall* and Gillian A. Gardner, Lewis & Clark College, Portland, OR 97219-7899.

An NSF-ILI grant was obtained to introduce computers into our first-year General Chemistry Laboratory program. We reviewed two potential sources of interfaces and transponders and settled on LabWorks. We have adapted our laboratories to use the new equipment for the detection and measurement of temperature, pH, potential at silver electrode, pressure, and light intensity change. Several new experiments were implemented directly in this first year. We will present the impact of this renovation on the student perceptions and the quality and quantity of data and understanding that has resulted. We will also present the results of a surveys completed by students on their perceptions of the utility of this method of data collection.

293. COMPUTERS IN THE FIRST YEAR GENERAL CHEMISTRY LABORATORY: ACID-BASE TITRATIONS. Gillian A. Gardner and William J. Randall*, Lewis & Clark College, Portland, OR 97219-7899.

The LabWorks interface was connected to a pH electrode and a drop counter. The titration was monitored by recording the pH at the instant the drop counter detected a drop of titrant passing through. The pH was plotted as a function of volume (either drops or mL units) and the equivalence point was determined by use of a first derivative curve superimposed upon the titration curve. Students used this method of data collection for two experiments. In the first experiment they selected a sample from a variety of acids and bases and proceeded to determine the concentration of the sample. In the second experiment the determined the titration curve for an unknown diprotic acid, the two equilibrium acid dissociation constants for the acid and the molecular weight of the unknown. From these data they were able to identify the unknown. We will present the experimental details and a sample of the programs that monitored this experiment.

294. DEVELOPING AN INTUITIVE APPROACH TO MOLES. Dawn M. Wakeley, Lindbergh High School, 16426 128th Avenue SE, Renton, WA 98058, and Hans de Grys, University of Washington, 3471 115th Avenue NE #225, Bellevue, WA 98004.

The mole is an important theoretical concept and a powerful tool in the study of chemistry. Traditional approaches to teaching the mole focusing on memorization and rote learning do not help students to develop the conceptual understanding and problem-solving skills necessary to be truly successful in chemistry. An alternative approach is to use discovery oriented laboratory exercises for students to develop an intuitive understanding of moles. Once students have discovered for themselves the utility and power of moles, the reason for using moles becomes obvious. Additional open-ended experiments provide students with the opportunity to apply this knowledge base in a non-directed laboratory setting.

295. FORCE MICROSCOPY IN FLUIDS. Stuart M. Lindsay, Department of Physics and Astronomy, Arizona State University, Tempe, AZ 85287.

Low amplitude dynamic force microscopy can operate in a non-contact mode, sensing changes in liquid properties near a surface. The operation of the microscope in water at the higher amplitudes often required for stable imaging has been investigated. When driven by direct application of a force to the tip, the microscope is stable over a wide range of operating frequencies. At low frequency, the interfacial stiffness extracted from approach curves is found to be on the order of 1N/m on first contact, indicative of imaging via a compressed liquid layer. Measurements of the spectral response of the cantilever and numerical simulations confirm this and show that viscous damping at the surface plays some role as well.

296. SCANNING TUNNELING MICROSCOPY OF IRON OXIDE SURFACES. Stephen A. Joyce*, Michael A. Henderson, and Scott A. Chambers, Pacific Northwest National Laboratories, MS K8-88, Richland, WA 99352.

The oxides of iron play an important role in geochemistry due to the energetically accessible redox couple of Fe(II)/Fe(III) in many natural environments. a-Fe2O3, hematite, is the most abundant fully oxidized form of iron oxide. Fe3O4, magnetite, is the most important reduced form. Scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) have been used to examine the structure of several surfaces of both hematite and magnetite. For the hematite (001) and (012) surfaces, bulk samples were used, whereas for the Fe3O4 (001) surface, MBE grown samples were studied. All of these surfaces exhibit reconstructions upon annealing in either vacuum or oxygen. These reconstructions are often associated with changes in the surface iron oxidation state and reflect the facile interconversions between the various iron oxide polymorphs.

297. DETERMINING THE SURFACE CHARGE OF IRON OXIDES USING ATOMIC FORCE MICROSCOPY. Sue B. Clark1*, Zheming Wang2, and Andy R. Felmy2, 1Chemistry Department, Washington State University, Pullman, WA 99164-4630 and 2Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratories, Richland, WA 99352.

Atomic force microscopy (AFM) has been used to determine surface charge on iron oxide thin films that were prepared by molecular beam epitaxy. Films of a-Fe2O3 were grown on sapphire substrates to produce either the (001) or (110) faces. The AFM cantilever was modified by attaching a well-characterized sphere of SiO2 to the tip. Using a flow-through system, interactions between the iron surface and the SiO2 sphere at a given pH were measured by obtaining a force curve. Changes in the interactions between the two materials are related to their surface charges, which are a function of pH. Our experimental observations will be discussed in the context of bulk surface charge measurements, and estimates of surface charge obtained using molecular dynamics calculations.

298. AFM AND SPECTROSCOPIC STUDIES OF STEARIC ACID AND CADMIUM STEARATE LANGMUIR-BLODGETT FILMS. Ursula Mazur* and Tanya Schmidt, Department of Chemistry and Materials Science Program, Washington State University, Pullman, WA 99164-4630.

Atomic force microscopy (AFM) was used to study stearic acid thin films as a function of deposition method, substrate, spreading pressure, pH, and cadmium(II) ion concentration. Freshly cleaved mica was found to be a superior substrate relative to freshly cleaned glass and chemically cleaned mica. Langmuir-Blodgett (LB) films of SA and of cadmium stearate (CdS) were studied in the spreading pressure range from the liquid phase through collapse. The CdS films were much more stable, and their collapse structure depended upon the subphase pH. Angle dependent XPS studies were combined with AFM height morphology measurements in order to determine the structure of the collapsed films. RAIR spectra of SA and CdS films are consistent with near the AFM height data.

299. A STUDY OF STEEL SURFACE CORROSION FILM IN BRINE USING XPS, AFM AND ICP-MS. Zheming Wang*, Andrew R. Felmy, and Marc J. Mason, Pacific Northwest National Laboratories, Richland, WA 99352 and Robert Moore, Sandia National Labs, Alburqurque, NM 87185.

Characterization of the surface corrosion film of steel in brines has a two-fold significance: it affects the safety of long term storage of heavy radionuclides at the waste disposal sites and potential reduction of high oxidation state heavy radionuclide to low oxidation states that is known to be less-mobile in the natural environment. In this work steel coupons were leached in synthetic brines for an extended period of time. Changes at the coupon surface at different depth were characterized by X-ray photoelectron spectroscopy, in-situ atomic force microscopy and ICP-MS under controlled environment. The results indicate that a compound, possibly FeClOH, develops on the coupon surface. The primary difference between the surface composition of the brine-contacted steel coupons and those of the water-contacted ones is that for the former cations and anions, such as Mg(II), Na(I), chloride and sulfate are incorporated into the corrosion layer.

300. RECRUITMENT AND ADVISING OF HIGH SCHOOL STUDENTS FROM "NONTRADITIONAL" GROUPS. Skip Rochefort, Chemical Engineering Department, Oregon State University, Corvallis, OR 97331-2702 and Michelle Bothwell, Bioresource Engineering Department, Oregon State University, Corvallis, OR 97331-2702.

The Summer Experience in Science and Engineering for Youth (SESEY) program was initiated in the summer of 1997 with the goal of promoting ethnic and economic diversity in the science and engineering fields through the recruitment of underrepresented minority high school students. Offered as a collaboration between Chemical Engineering and Biological Engineering at Oregon State University, the program has two primary focus groups: (1) traditionally underrepresented students (ethnic minorities and girls) who have completed their freshman, sophomore or junior years in high school, and who have an interest in math and science, and (2) science, math, and physics teachers at High Schools which have a substantial population of the student focus groups.

301. CREATING AN ATMOSPHERE FOR SUCCESS FOR MINORITY STUDENTS AT THE UNIVERSITY OF WASHINGTON. Kathryn "Nan" Little, MSEP ALVA Coordinator, University of Washington, Box 352180, Seattle, WA 98195-2180.

Despite the passage of I-200, the anti-affirmative action initiative, in November 1998, outreach programs for minority students at the University of Washington continue stronger than ever, although with some modifications. Minority outreach focuses on three areas: preparation, recruitment and retention. Initiatives in Engineering, Chemistry, Health Sciences and through the Equal Opportunity Programs target academic preparation for K-12 students and teachers. Rather than recruiting individual minority students, our efforts are now focused on geographic pockets of diverse students, such as inner city and reservation schools. Our retention workshops, which were formerly for minority students, are now open to all, but special encouragement is given to minority students to participate. Using focused preparation, recruitment and retention strategies, minority retention for students in our ALVA Engineering program is at 90%. This talk will focus on specific minority outreach and retention efforts at the UW.

302. SMILE HAS THE FORMULA TO GET UNDERREPRESENTED STUDENTS INTO COLLEGE. Molly Bloomfield, SMILE PROGRAM, 18 Gladys Valley Center, Oregon State University, Corvallis, OR 97331-3510.

SMILE (Science and Math Investigative Learning Experiences) is a collaboration between Oregon State University and Oregon school districts to provide math and science enrichment in after-school science clubs for minority and disadvantaged youth. The purpose of the SMILE Program is to increase the number of underrepresented students who graduated from high school qualified to go on to higher education and pursue careers in science, math, engineering, teaching, and the health professions. SMILE hands-on science and math activities are centered in weekly after-school club meetings and monthly field trips to places of scientific interest. Now, after 11 years, the program can demonstrate remarkable success in keeping these students in school, graduating from high school, and going on to higher education. Eighty five percent of SMILE students who participated in SMILE for more than one year have graduated from high school. Since 1992, over 80% of students who graduated as SMILE seniors have continued on to college.

303. PANEL DISCUSSION: NETWORKING AMONG WOMEN IN CHEMISTRY. J. P. Kilbourn, Consulting Clinical and Microbiological Laboratory, 333 S.W. 5th Ave., #620-7, Portland, OR 97204.

Women need to support one another. A panel of women will tell what they have done, what they are doing, and why what they are doing seems to work for them. Panel members include representatives from academia, namely: Angela Hoffman, a Professor of Chemistry at the University of Portland, and Sue Eggling, an instructor at Clackamas Community College; and representatives from a large company, Mary Ryan-Hotchkiss, an employee of Tektronix, from a small company, Gwen Llewellyn, who is an employee of Interfacial Dynamics, and a one-person laboratory, J. P. Kilbourn, owner and CEO of Consulting Clinical and Microbiological Laboratory. The panel will be moderated by Patricia Stoddard, Instructor at ConCorde Career Institute.

304. CHEMIST COMPOSERS. Carl C. Wamser, Department of Chemistry, Portland State University, Portland, OR 97207.

Several examples of chemists who were also successful composers of music will be cited and compared, including Alexander Borodin, Sir Edward Elgar, Emil Votocek, Lejaren Hiller, and Elaine Bearer.

305. PERFORMANCES OF STRING QUARTETS COMPOSED BY CHEMISTS OF THE 19TH AND 20TH CENTURIES. String Quartet from the Community Music Center, Portland, OR.

Performances of two full string quartets will be presented by young musicians from the Community Music Center: Lisbeth Dreier and Megumi Stohs, violins, Evan Denton, viola, and Jared Ballance, cello. In preparing for this performance, they have been under the guidance of Naomi Blumberg, cellist with the Oregon Symphony. The first work presented will be the String Quartet No. 4 (1957) by Lejaren A. Hiller, Jr., and Leonard M. Isaacson, who were chemists working in the research group of Fred Wall at the University of Illinois at the time. The piece is generally considered to be the first piece of music composed by a computer (following instructions created by Hiller and Isaacson). The second work will be the delightful String Quartet No. 2 in D (1883) by Alexander Borodin, filled with melodies made familiar by their later incorporation into the popular musical Kismet.

306. THE FASCINATION OF NATURAL PRODUCTS. Steven J. Gould, Executive Director, Natural Products Drug Discovery, Merck and Company, P.O. Box 2000, RY80Y-320, Rahway, NJ 07065.

Recent examples from the area of natural products chemistry will be presented.

307. EMPLOYMENT FOR CHEMISTS IN THE NEW MILLENNIUM: WHERE THE JOBS ARE. Madeleine Jacobs, Editor-in-Chief, Chemical and Engineering News, American Chemical Society, 1155 16th Street NW, Washington, DC 20036.

In real estate, the three most important factors determining the value of property are location, location, location. In determining the employment outlook for chemists, the watchwords are the economy, the economy, the economy. Over a period of 50 years, the job market for chemists has always been a reflection of the state of the U.S. economy. This talk will review the near-term employment situation for chemists in industry, academia, and elsewhere and discuss the outlook for chemists in the new millennium. The speaker will place emphasis on the biotechnology field as a source of jobs and provide information on what employers are looking for in chemically trained professionals.

308. EXCITING AFM CANTILEVERS UNDER FLUID FOR BIOSURFACE ANALYSIS. Michael J. Allen*1, C. Moeller2, V. Elings1, A. Engel2, and D. J. Mueller2, 1Digital Instruments, 112 Robin Hill Road, Santa Barbara, CA 93117 and 2M. E. Mueller Institute for Structural Biology, Biozentrum, Klingelbergstr. 70, CH-4056 Basel, Switzerland.

A major goal in the field is to increase spatial resolution under fluid while also controlling excess contact forces exerted on the specimen to a verifiable minimum. Biological specimens are commonly hydrated and soft, and very loosely attached to a surface. These specimens tend to be cut, squeezed or pushed by the scanning probe- sometimes even though great care is taken by the operator. Tapping-mode AFM (TMAFM) has helped this situation due to the fact that the specimen experiences only a brief vertical force as opposed to a rubbing-like force that occurs during contact-mode AFM (CMAFM). While extremely high resolution is possible using CMAFM (in some cases approaching 0.5 nm), the rubbing-like forces limit the usefulness of CMAFM for true in situ imaging. We tested the resolution performance of fluid TMAFM on several delicate biological specimens. Presented are optimal instrument parameters for achieving high resolution TMAFM at low force. The lateral and vertical resolutions of TMAFM under fluid were determined to be 1.1 nm and 0.1 nm respectively. The TMAFM imaging force was predicted to be less than 100 pN based on previous CMAFM observations on the same sample.

309. NANO-CONFINEMENT OF LIQUID-LIKE MATERIAL AT INTERFACES. Rene M. Overney, Department of Chemical Engineering, University of Washington, Seattle, WA 98195.

Mechanical properties of elastomeric material at interactive interfaces are found to be retarded from bulk properties even at distances where mean-field theories predict bulk properties. The far-reaching retardation effect is due to structural anisotropy that is the result of the film preparation (spin coating), the interaction with the solid substrate and diffusion during the annealing process. Our recent measurements of surface mechanical properties on ultrathin elastomer films will be discussed in this paper. With atomic force microscopy, x-ray, SIMS and neutron reflection we investigated the diffusive and mechanical properties as function of the film thickness, the polymer molecular weight, and the interaction strength of the interface. We will present recent glass transition measurements on homopolymers and polymer blends and discuss the effect of confinement and instrumental force-instability-methods on transition properties of fluids.

310. NANOMETER SCALE INVESTIGATIONS OF CORROSIVE WEAR OF A INORGANIC SINGLE CRYSTALS. J. T. Dickinson, Department of Physics, Washington State University, Pullman, WA 99164-2814.

In several mechanical wear situations, e.g., biomaterials in joints and teeth, a surface experiences simultaneous tribological loading and corrosive chemical exposure. The combination can greatly increase wear rates. We examine several inorganic single crystals in buffered aqueous solutions mechanically stimulated by the tip of a Scanning Force Microscope (SFM). Quantitative data on nanometer-scale wear of single atomic layer steps are readily obtained. Stress-enhanced dissolution of steps is readily observed along three crystallographic directions with striking differences in rate and highly non-linear dependence on contact force. We discuss the mechanism of corrosive wear and the vulnerability of steps in terms of the surfaces many microns in dimension. We also present results on tip-manipulated re-deposition.

311. THE EFFECT OF INTERFACIAL CONSTRAINTS ON THE GLASS TRANSITION TEMPERATURE OF ULTRATHIN POLYMER FILMS STUDIED BY SCANNING FORCE MICROSCOPY. Cynthia Buenviaje, Shouren Ge, Ryan Buckmaster, Jim Dornicik, Xuesong Hu, Jonathan Sokolov, Miriam Rafailovich, and René M. Overney*, University of Washington, Department of Chemical Engineering, Seattle, WA 98195.

The mechanical properties of polymer films depend, in a complex manner, on the film preparation technique in conjunction with interfacial interactions as illustrated in this paper. Existing classical mean-field theories or molecular dynamic simulations assume that, for instance, interfacial interactions are completely screened within a distance corresponding to the persistence length of the polymer. We will introduce in this paper scanning force microscopy as a technique that can measure the local shear properties of an ultrathin polymer film. Lateral shear modulation measurements in combination with a highly accurate temperature stage provide insight into the glass transition of polymers as function of the film thickness. We will discuss how and why interfacial interactions can affect the shear mechanical properties of spin-coated polymer films up to a distance that exceeds the polymers' persistence lengths by far.

312. INTERACTION FORCE MEASUREMENTS CONDUCTED BY ATOMIC FORCE MICROSCOPY. Amy Szuchmacher, Ellen McNeil, Karra Nichols, Thomas Engel, and René M. Overney*, Department of Chemistry, University of Washington, Seattle, WA 98112.

Understanding the interaction forces between different materials is very important in many fields such as tribology, materials science, bioengineering, and polymer science. This work presents interaction force measurements made with an atomic force microscope (AFM) using ultrasharp, chemically well-defined
functionalized cantilevers. The functionalized levers were produced by the direct reaction of silanes with a silicon tip, resulting in a monolayer coverage of a polymeric network film. This results in a much smaller tip radius and better tip stress resistance when compared to traditional functionalization techniques involving thiol self-assembled monolayers produced on gold coated cantilevers. The tips were used to measure interaction forces in a variety of environments, including dry air, water, ethanol, cyclohexane, and hexadecane.

313. BIOGEOCHEMICAL PROCESSES CONTROLLING THE OCCURRENCE AND MOBILITY OF ARSENIC IN NATURAL WATERS. J. G. Hering, Environmental Engineering Science, California Institute of Technology, Pasadena, CA 91125

The occurrence of elevated concentrations of arsenic in natural waters has come under increasing scrutiny because of the anticipated change in the drinking water standard for arsenic from its current value of 50 ppb to a new value in the range of 20 to 2 ppb. The chemistry of arsenic in natural waters and the biogeochemical processes controlling its occurrence and mobility will be briefly reviewed. Two contrasting case studies will be presented in which concentrations of naturally-occurring arsenic pose significant problems for public water supply. In the source waters of the Los Angeles Aqueduct, arsenic is of geothermal origin. The redox cycling of arsenic in the water column and the factors affecting its mobility will be discussed. In the southern San Joaquin Valley, elevated arsenic concentrations in groundwater are associated with alluvial sediments. The vertical segregation of arsenic and variations in arsenic oxidation state will be examined.

314. THE USE OF A ROTATING ANNULAR FLUME TO STUDY THE TRANSPORT AND OXIDATION OF ACID VOLATILE SULFIDES IN SHEAR FLOWS. Jeffrey E. Bailey-Darland*, Anna M. Farrenkopf, William Fish**, Paul G. Tratnyek, and Antonio M. Baptista. Department of Environmental Science and Engineering, Oregon Graduate Institute of Science and Technology, Portland, OR 97291-1000. **Department of Civil Engineering, Portland State University, Portland, OR 97207-0751.

A Rotating AnnuLar Flume (RALF) has been constructed as a biogeochemical research tool for the study of sediment-water interfaces affected by shear. RALF provides a shear flow without end effects with which to study the coupling of biogeochemical processes to transport and particle dynamics (e.g., flocculation and settling). We will present results from experiments in RALF showing oxidation and transport of acid-volatile sulfides (AVS) in intermittently suspended sediments (Young's Bay, OR). Sediments were slurried, injected into a flow field (RALF) and allowed to settle. Total suspended sediments and AVS were measured on grab samples, while parameters such as flow field velocity, dissolved oxygen, and pH were monitored in "real-time". Our results suggest that particle-associated AVS from disrupted sediments persists in the water column longer than expected from the simple coupling of first order reaction models with particle settling models.

315. IN SITU REDOX-SENSING: SOLID STATE MICRO-ELECTRODE PROFILES OF PORE-WATER CHEMISTRY AT THE SEDIMENT WATER INTERFACE UNDER FLOW CONDITIONS IN A ROTATING ANNULAR FLUME (RALF). Anna M. Farrenkopf*, Jeffrey E. Bailey-Darland, Dmitri Sobelez**, António M. Baptista, David R. BooneÝ, Paul G. Tratnyek, and William FishÝ. Center for Coastal and Land-Margin Research, Oregon Graduate Institute of Science and Technology, Portland, OR 97291-1000. **Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35487. ÝPortland State University, Portland, OR 97209-0751.

To advance our quantitative understanding of electro-active chemical species in suspended estuarine sediments we intend to couple innovative meso-scale experimentation in RALF with diagnostic numerical modeling and field observations. Here we report our results from preliminary flume experiments. Sediment and river water were collected from Young's Bay, OR, and transported to Oregon Graduate Institute. Following the reconsolidation and compaction of the sediment bed (~ 60 days), porewater profiles were collected. Gold/mercury amalgam electrodes positioned 2 cm above the sediment water interface, were submerged in the flume and repositioned at 1 mm intervals at and below the interface to a depth of 5 cm. Profiles were obtained for: oxygen, peroxide, manganese, iron, sulfide, and metal sulfides. The distributions of the chemical species corresponded well to the visual structure of the layering of the particles. Most probable number analyses of bacterial abundance also corresponded with the distribution of reduced metal species present.

316. PROBING OXIDATION-REDUCTION REACTIONS IN ANAEROBIC SEDIMENTS WITH INDICATOR DYES AND 2-CHLOROACETOPHENONE. Thea E. Reilkoff1, Brad D. Henegar2, Tony Lemon1, and Paul G. Tratnyek1*, 1Department of Environmental Science and Engineering, Oregon Graduate Institute, Portland, OR 97291 and 2Banks High School, Banks, OR 97106.

One of the outstanding questions regarding the chemistry of environmental contaminant degradation is the identity of chemical agents responsible for reduction reactions in anaerobic sediments, soils, and sludges. Due to the complex nature of these environments, identification of reducing agents has proven challenging. One method that shows potential is the use of chemical probes that give reaction products (or kinetics) that are diagnostic for particular reduction mechanisms. Redox indicators (including sulfonated indigos, tetrazoliums, indophenols, and resurofin) and 2-chloroacetophenone (2-CAP) have proven successful in distinguishing and quantifying reductive transformations. 2-CAP is of particular interest because it is the agent responsible for reduction. Due to the complex nature of sediments and changing environmental conditions, seasonal variations in reduction rates and pathways are observed. To better understand this phenomenon, an extensive chronological study of field conditions has been implemented.

317. SOURCES FOR SEASONALITY OF SUSPENDED MANGANESE OXIDE CONTENT IN THE COLUMBIA AND WILLAMETTE RIVERS. Paul A. Covert* and Fred G. Prahl, College of Oceanic & Atmospheric Science, Oregon State University, OR 97331.

Recent work in the Columbia and Willamette rivers has revealed a seasonal peak in the ratio of manganese to aluminum (Mn/Al) associated with suspended particulate material (SPM). This peak is centered between May and July, corresponds with primary production in both rivers, and shows a 200 to 400% elevation of Mn/Al over a crustal average of 0.011 (wt/wt). Two independent explanations could account for this observation. 1) Agriculture initiates two chains of events that result in a mobilization Mn in the soil to the river (ultimately yielding an increase in MnO2) and also increased river primary production, supported by runoff of excess fertilizer. 2) Increased river primary production creates conditions required to oxidize aqueous Mn+2 to solid MnO2. Analysis of the Mn-enriched SPM using selective leaching techniques and visual inspection of manganese oxide by scanning electron microscopy provide insight into the process(es) responsible for the seasonal Mn/Al peak.

318. BEHAVIOR OF PCBs IN THE COLUMBIA SLOUGH. William Fish, Department of Civil Engineering, Portland State University, Portland, OR 97207-0751.

A multimedia fugacity model of PCB behavior was developed for Buffalo Slough, a segment of the Columbia Slough in Portland, OR. The model was used to evaluate contaminated sediment and stormwater and their relative contributions to the uptake of PCBs by large edible fish (carp). Sediment sources are predicted to account for >80% of fish-tissue uptake, indicating that stormwater controls may have little impact on PCB levels in carp. However, attaining tissue levels that correspond to acceptable cancer risk levels in humans consuming the fish may require >99% removal of PCBs from the sediments. Sensitivity analysis showed desorption kinetics to be a key control on PCB exposure in this system, as well as the main limitation to natural depuration of the sediments. The findings reveal the usefulness of multimedia models in defining the principle pathways of PCBs and the probable response of the system to various remediation options.

319. NEAR REAL-TIME MONITORING USING SIRE-TECHNOLOGY BASED AMPEROMETRIC BIOSENSORS. Kirstin Krizb* and Dario Kriza,b, aChemel AB, Research Park IDEON, SE-223 70 Lund, Sweden and bDepartment of Pure and Applied Biochemistry, Chemical Center, University of Lund, P.O. Box 124, SE-221 00 Lund, Sweden.

A microprocessor controlled SIRE technology based biosensor is reported. The sensor principle is based on a peroxidase or dehydrogenase enzyme flow injection that allows differential measurements. No sample injection is performed. Optimization has been done for the analytes glucose (L.O.D. = 2 micromolar and the upper dynamic range 300 mM), ethanol (L.O.D. = 10 micromolar and the upper dynamic range 1M) and galactose (L.O.D. = 100 micromolar and the upper dynamic range 150 mM). Furthermore, detection of sucrose (L.O.D. = 50 micromolar and the upper dynamic range 300 mM) and lactose (L.O.D. = 5 mM and the upper dynamic range 300 mM) is reported. The relative sample deviation is between 0.4% (buffered samples) and 5% (crude samples). Two new application areas are demonstrated: in situ (real-time) fermentation monitoring of two analytes simultaneously (glucose and ethanol) and steps toward in vivo monitoring of glucose and lactate using a needle-formed electrode.

320. THE USE OF PARAMAGNETIC LABELS IN A NEW IMMUNOASSAY TECHNOLOGY CALLED MAGNETO IMMUNOASSAYS. Kirstin Kriz and Dario Kriz*, European Institute of Science, Research Park IDEON, SE-223 70 Lund, Sweden and Department of Pure and Applied Biochemistry, Chemical Center, University of Lund, P.O. Box 124, SE-221 00 Lund, Sweden.

A new immunoassay technology has been introduced by our group, referred to as a Magneto Immunoassay, which is based on the use of nanosized, paramagnetic labels that have been functionalized with antibodies, thus, allowing the label to interact specifically with the target analyte in complex samples. A hand-held instrument has also been developed to determine the concentration of target analyte by measuring the magnetic permeability of the labeled samples. Past feasibility studies include the detection of the protein Concanavalin A in the dynamic range of 0-1.9 micromolar with a limit of detection at 250 nM. Current studies will also be presented with an emphasis on clinically interesting analytes.

321. A NEW DESIGN FOR A MATRIX-ASSISTED LASER DESORPTION/IONIZATION TANDEM TIME-OF-FLIGHT MASS SPECTROMETER. Douglas F. Barofsky* and Daniel L. Katz, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

We have designed and constructed a novel matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometer. The first stage of mass spectrometry employs delayed extraction to space-focus the ions onto the entrance plane of a high resolution velocity selector. After selection, the precursor ions are accelerated to much greater kinetic energies and then reflected in an electrostatic mirror. This second stage of acceleration performs the dual function of converting the ensemble of precursor and product ions from one of constant-velocity to one of nearly constant energy and space-focusing the entire ensemble onto the object plane of the ion-reflector. The multiplex detection that characterizes linear time-of-flight mass analysis is thereby fully preserved. The design and construction features of this new instrument will be presented along with experimental results. The latter will illustrate the instrument's utility in obtaining amino acid sequence information from peptides.

322. presented as paper # 248

323. PERFORMANCE EVALUATIONS FOR METAL ION CAPTURE OF SILICA-POLYAMINE COMPOSITES WITH DIFFERENT PARTICLE AND PORE SIZES. Dana Hagers, Edward Rosenberg*, and John Deming, Department of Chemistry, The University of Montana, Missoula, MT 59812.

We have been developing a series of silica-polyamine composite materials for the removal and recovery of transition metal ions from aqueous waste streams. Both the silica gel and the polyamine are available with a range of properties. The polyamine can be obtained in molecular weight ranges of 300-40,000 Daltons and in linear and branched forms. Fumed silica gel is available in a wide range of particle and pore sizes. We have found that in order to maintain reasonable hydraulic throughput, 100 micron silica is the minimum particle size. In this report, we will present the results of our studies on how particle and pore size influence the metal ion capacity and the thermal and mechanical stability of these composite materials.

324. DETERMINATION OF I-129 IN LICL/KCL EUTECTIC SALT. Mary L. Adamic* and Jeffrey F. Berg, Analytical Laboratory, Argonne National Laboratory - West, P.O. Box 2528, Idaho Falls, ID 83401.

ANL-West is demonstrating the electrometallurgical treatment of spent nuclear fuels from the EBR-II reactor. A KCl/LiCl eutectic salt is used as "solvent" for this process. Once the eutectic salt has been used in the electrorefiner it begins to accumulate fission products such as I-129. The concentration of the I-129 in the eutectic salt and later in the ceramic waste form made from the eutectic salt is important to those developing a model for the electrorefiner. Those developing the ceramic waste form are also interested in whether the I-129 leaches from the waste form. This talk will discuss a method developed for the separation, purification and analysis of I-129 contained in eutectic salt and ceramic waste form samples. The method of sample collection, preparation, purification and analysis will be detailed. The method in brief; samples are taken from the electrorefiner, dissolved in water (base added) in a hotcell, carrier added, separated using ion chromatography in a glovebox and counted for I-129 content using liquid scintillation counting.

325. DETECTION OF GASEOUS ANALYTES USING LED DIE CHIPS. Arthur B. Ellis,* Albena Ivanisevic, Joel A. Olson, Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706; and Thomas F. Kuech, Department of Chemical Engineering, University of Wisconsin-Madison, Madison, WI 53706.

The photoluminescence (PL) and electroluminescence (EL) intensity of a variety of LED die chips based on III-V semiconductor compositions can be reversibly altered by adsorption of gaseous analytes such as amines and sulfur dioxide. Possible mechanisms for the direction and magnitude of the PL and EL responses will be presented along with estimates of binding constants. Deployment of these structures in sensing environments will be discussed.

326. Note - the paper previously listed as # 326 has been moved to poster # 113

327. SURFACE INDUCED CALCIUM PHOSPHATE NUCLEATION AND GROWTH. Marisol Avila* and Allison A. Campbell, Materials Sciences Department, Pacific Northwest National Laboratory, Richland, WA 99352.

Calcium phosphate is a major constituent of both bones and teeth. Therefore, they have been adopted as bone fillers and coatings for orthopedic implant materials. Current research at Pacific Northwest National Laboratory is focused on the development of techniques to mineralize calcium phosphate coatings on implants. However, the relationship between the surface chemistry and the crystal nucleation kinetics of calcium phosphate is still not well understood. In order to understand how the surface chemistry of the material affects calcium phosphate crystal nucleation kinetics, TiO2 was chosen as the model surface. The constant composition kinetics technique was used to measure the nucleation induction times of the calcium phosphate nucleation on TiO2. To learn more about the TiO2 surface charge properties, zeta potential measurements were taken. The relationship between the surface chemistry of TiO2 and calcium phosphate nucleation kinetics is still under investigation. Preliminary results have shown that the TiO2 nucleation induction time is 120 minutes.

328. INCORPORATION OF BIOACTIVE AGENTS INTO CALCIUM PHOSPHATE COATING. X. Shari Li*, Lin Song, and Allison A. Campbell, Pacific Northwest National Laboratory, Richland, WA 99352.

Calcium phosphate coating on the implant surface has been recognized as bone bonding biomaterial. Incorporation of bioactive agents, such as growth factors and other proteins into surface coatings may produce a device that initiates the new bone. Resistance to infection may also be achieved by incorporating antimicrobial agents into mineral coatings on the implants. The goal of this study is to develop and characterize calcium phosphate coatings that are bioactive agents incorporated. The Surface Induced Mineralization (SIM) process, an aqueous based process, was used for the deposition of calcium phosphate coatings. Different processes of incorporation antimicrobial agents into calcium phosphate coating were studied and the properties of the coating films were characterized using techniques such as XRD, FTIR, and SEM. The release of bioactive agents from the thin films under physiological condition was investigated and a sustained release can potentially be achieved.

329. SYNTHESIS OF NEW VOLATILE LIQUID COPPER PRECURSOR FOR CHEMICAL VAPOR DEPOSITION OF COPPER THIN FILMS. Wei-Wei Zhuang*, Tue Nguyen, Larry Charneski, David R. Evans and Sheng Teng Hsu, Sharp Microelectronics Technology, Inc., 5700 NW Pacific Rim Blvd., Camas, WA 98607.

A new volatile liquid copper precursor has been synthesized. At room temperature, crystal precipitation was observed from the fresh-made liquid copper organometallic precursor over a period of time. To prevent the crystal precipitation, the synthesis procedure has been modified, in which a stabilizer has been introduced. No any solid or crystal was precipitated from the stabilized liquid copper precursor over several months. The mechanism for the liquid phase stabilization has been proposed based on the studies of its NMR spectra. Pure copper thin films have been prepared via chemical vapor deposition by using this new copper organometallic precursor. The copper thin films have exhibited excellent adhesives to metal nitride substrates. The resistivity of the copper thin films is about 1.8 mWcm

330. TOWARD BIMETALLIC FERRIMAGNETIC MATERIALS: SYNTHESIS, CHARACTERIZATION AND STRUCTURE OF TRANSITION METAL COMPLEXES OF 4'-METHYLTHIO-2,2':6',2"-TERPYRIDINE**. James R. Jeitler*, Department of Chemistry, University of Idaho, Moscow, ID 83844-2343; Mark M. Turnbull, Carlson School of Chemistry, Clark University, Worcester MA 01610; and Jan WikairaÝ, Department of Chemistry, University of Canterbury, Christchurch, New Zealand.

Terpyridine and its derivatives have long interested coordination chemists due to their ability to form stable transition metal complexes. We can utilize this trait in the synthesis of alternating site, bimetallic, coordination polymers. Initial attempts to make these systems focused on the ligand 4'-methylthio-2,2':6',2"-terpyridine (MeStrpy). Complexes of the type [M(MeStrpy)2](ClO4)2 (M = Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) were prepared as well as the Zn(MeStrpy)Cl2 complex. Elemental analysis, IR and NMR spectroscopy, room temperature magnetic susceptibility and x-ray crystallography were used to characterize these complexes.
** Supported in part by NSF grant DMR-9006470 and Department of Education GAANN grant
Ý Current address: Department of Chemistry, Brown University, Providence, RI 02912

331. CRYSTAL CHEMISTRY OF THE CU(II) HALIDE/4,4'-DIMETHYL-2,2'-BIPYRIDINE SYSTEM. Roger D. Willett*, George Pon, Callie Nagy and Eric Lavy, Department of Chemistry, Washington State University, Pullman, WA 99164 and Ashwani Vij, University Research, University of Idaho, Moscow, ID 83844.

The crystal chemistry of the compounds obtained by the reaction of CuCl2 and CuBr2 with L = 4,4'-dimethyl-2,2'-bipyridine is reported. For the chloride series, compounds obtained include LCuCl2.H2O, (LCuCl2)2.H2O, LCuCl2(DMSO) and (LH2)CuCl4. In the corresponding Br series, the following compounds were obtained: LCuBr2, LCu2Br4 and (LH2)CuBr4. For LCuCl2.H2O, a five-coordinate CuN2Cl2O species of found, intermediate between square pyramidal and trigonal bipyramidal geometry. A similar geometry is found in LCuCl2(DMSO). In (LCuCl2)2.H2O, a five-coordinate chloro-bridged dimer is found. In contrast, LCuBr2 contains stacks of square planar complexes with CuN2Cl2 coordination. The LCu2X4 compounds contain stacks of planar dimers in which one Cu atom has a planar CuN2X2 coordination while the other has a planar CuX4 coordination. Magnetic properties of several of the salts will be presented.

332. IN VACUO REACTIONS OF ALKANETHIOL WITH OXIDE-SUPPORTED METAL NANOPARTICLES. Earl L. Smith, Wen Y. Yin, Joseph Ramos, Miriam Perez, and Karen Chan, Department of Chemistry, University of Texas at El Paso, El Paso, TX 79968.

Alkanethiols are reacted with gold nanoparticles supported on either alumina or titania and rhodium nanoparticles supported on silica. In Vacuo Infrared Transmission spectroscopy shows loss of the SH stretch upon alkanethiolate film formation at both rhodium and gold. Using gas chromatography, we have detected dihydrogen after film formation on gold nanoparticles. These results demonstrate dissociative chemisorption of the alkanethiol on rhodium and gold nanoparticles. Mechanistically, this can be explained with concomitant formation of a surface metal hydride, which in vacuum, desorbs as diatomic hydrogen. Comparisons are made with solution formed films.

333. SELF-ASSEMBLY OF INORGANIC/ORGANIC MULTILAYER THIN FILMS: INCORPORATION OF NONLINEAR OPTICAL PROPERTIES. Catherine J. Page, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Layer-by-layer synthesis of inorganic-organic multilayer thin films allows the construction of materials with control of thickness, chemical composition, properties and proximity of different layers for use in a variety of applications. By utilizing different types of organic-inorganic bonding which can be exploited to self-assemble multilayer films, we are able to incorporate oriented layers of chromophores that give rise to nonlinear optical properties. Examples of these types of multilayers grown on silicon wafers and their characterization by ellipsometry, grazing-angle x-ray diffraction, XPS and second harmonic generation will be presented.

334. SOLAR ENERGY CONVERSION IN AN ARTIFICIAL PHOTOSYNTHETIC MEMBRANE. Thomas A. Moore*, Ana L. Moore, Devens Gust, Wayne Frasch, Gali Steinberg, Hebe Vanegas, and Theresa Harper, Center for the Study of Early Events in Photosynthesis, Department of Chemistry and Biochemistry, and Department of Plant Biology, Arizona State University, Tempe, AZ 85287-1604.

We have assembled a liposome-based artificial photosynthetic membrane that uses light energy to produce ATP. Photoinduced electron transfer in a triad-based artificial reaction center converts light energy to vectorial redox potential across a liposomal membrane which drives a quinone-based redox loop that generates proton motive force. The pmf powers the synthesis of ATP by CFo-F1 ATP synthase incorporated into the liposomal bilayer. The ratio [ATP]/[ADP][Pi] is the thermodynamically significant parameter characterizing the ATP potential. Synthesis occurred up to a limiting equilibrium value of [ATP] ~ 1600 [ADP] with [Pi] = 5 mM. The poise of the ADP + Pi = ATP reaction at this ratio requires considerable proton motive force, ~ 4 kcal/proton, and represents a significant conversion of light energy to chemical potential. The energy charge in terms of ATP potential produced by the artificial membrane, ~ 16 kcal/mole, is comparable to that of a natural photosynthetic membrane.

335. PHOTOSWITCHABLE ORGANOGELS RESULTING FROM COMPETING SELF-ASSEMBLY ELEMENTS IN THE GELATOR. David G. Whitten*, Liaohai Chen, Cristina Geiger, Marina Stanescu, Dean Duncan, and Jerry Perlstein, Los Alamos National Laboratory, Los Alamos, NM 87545 and Center for Photoinduced Charge Transfer, University of Rochester, Rochester, NY 14627.

Organogels, visco-elastic solids comprised of a typical organic solvent and a gelator may be formed from a variety of solvent-gelator combinations. Our focus has been on gelators consisting of two self-assembly units - one a steroid and the second an aromatic such as trans-stilbene or a squaraine dye - tethered by a short, flexible chain. In several cases gel formation can occur at very low levels of gelator, typically 1 molecule per several thousand solvent molecules. Fractal or fibrous structures can be observed at the nano (AFM or electron microscopy), meso or macro level. Although the structure is macroscopically solid, the behavior of much of the solvent and solute guests appears more solution-like. The role of structure, solvent and gelator chirality and other factors will be discussed.

336. A CONCISE SYNTHESIS OF FUMAGILLOL. Erik J. Sorensen*, David Vosburg, and Sven Weiler, Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd, La Jolla, CA 92037.

Interest in the biological properties of fumagillin, a fungal metabolite renowned for its anti-parasitic properties since the early 1950's, experienced a renaissance after Folkman and coworkers discovered that fumagillin and its semi-synthetic derivative TNP-470 have the remarkable capacity to inhibit the proliferation of endothelial cells in vitro and tumor-induced angiogenesis in vivo. Since unregulated angiogenesis can cause the growth and metastasis of malignant tumors and other inflammatory diseases, inhibitors of this process are of considerable interest as potential chemotherapeutic agents. In this lecture, a concise stereocontrolled synthesis of fumagillol, the immediate precursor of fumagillin and TNP-470, from abundant and inexpensive starting materials will be described. The convergent nature of our strategy may facilitate the synthesis of manifold fumagillin-like small molecules which may show utility as inhibitors of angiogenesis. Recent progress in the chemical synthesis of other biologically active natural products will also be addressed.

337. NOVEL LIGANDS FOR THYROID HORMONE RECEPTORS. Thomas S. Scanlan, Departments of Pharmaceutical Chemistry and Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143-0446.

Thyroid hormones are important endocrine signaling molecules that mediate a variety of biological processes in mammals. Signaling is accomplished by hormone binding to the thyroid hormone receptor (TR) which is a member of the nuclear receptor superfamily of ligand-activated transcription regulators. There are two different TRs, TRa and TRb, and the two TRs are expressed at different ratios in different tissues. It is currently hypothesized that the two different TRs have distinct physiological roles in different tissues and at different stages of development. In terms of TR ligand design, two central questions can be asked: How do ligands turn the TR on and off, and can ligands be made that distinguish TRb from TRa? I will present recent data from my laboratory that addresses these two questions.

338. SMALL MOLECULE ELECTROPHILES AS NOVEL PROTEIN DISCOVERY TOOLS. Matthew S. Bogyo, University of California, San Francisco, Department of Biochemistry and Biophysics, San Francisco, CA 94143-0448.

Small organic molecules and peptides have long been exploited to modulate the activity of a given target enzyme. Important drugs are usually discovered by screening large libraries of natural products or chemically synthesized compounds using a single biological assay. In most cases the targeted enzyme has been fully characterized and in many cases complete crystal structures are known. While this use for small molecules is certainly of great importance, the potential for use of the small molecule as a discovery tool is often overlooked. We propose to exploit small, electrophilic peptides which covalently tag a target in the process of inhibition. These compounds are likely to be extremely valuable reagents for the identification of novel nucleophilic enzymes involved in a wide variety of biological processes. We have found that C-terminal vinyl sulfone peptides represent a new class of suicide substrate inhibitors of the threonine protease known as the proteasome. Michael addition of the hydroxyl nucleophile to the vinyl sulfone renders the protease inactive and simultaneously results in a covalent, irreversible modification of the active site. Attachment of a radio-label at the N-terminus of the peptide vinyl sulfone allows specific detection of the target protein by simple SDS-PAGE. A series of labeled vinyl sulfone inhibitors have been synthesized and were used to study substrate binding and specificity of the proteasome.

339. CHEMICAL AND BIOLOGICAL CELL SURFACE ENGINEERING. Carolyn R. Bertozzi, Department of Chemistry, University of California, Berkeley, CA 94720.

Cell surface molecules govern the 'social behavior' of cells and participate in fundamental processes such as cell adhesion and signal transduction. Among the structures found on cell surfaces, glycoconjugates (glycoproteins and glycolipids) predominate as the carriers of molecular information, their diversity engendered largely by their pendant oligosaccharides. My laboratory is interested in how the chemical and biological modulation of carbohydrate structures inside a cell can be used to alter the structures on the cell surface and, consequently, the biological interactions of the cell. Two examples from our recent research will be discussed. First, we have shown that the biosynthesis of unnatural carbohydrate molecules inside cells can be exploited for the chemical control of cell surface landscapes. Novel functional groups can be installed on cell surfaces and used to engineer novel viral binding activities. Second, we have elucidated a biological mechanism for altering cell surface structures, oligosaccharide sulfation catalyzed by intracellular carbohydrate sulfotransferases. These enzymes play a role in modulating leukocyte-endothelial adhesion at sites of inflammation and are therefore possible targets for anti-inflammatory therapy.

340. ANALYSIS OF PROTEIN TRAFFICKING USING GREEN FLUORESCENT PROTEIN
HYBRIDS. Janis E. Lochner*, Chad D. Meliza, and Bethe A. Scallettar, Departments of Chemistry and Physics, Lewis & Clark College, Portland, OR 97219.

Advances in fluorescence microscopy promise to enhance our understanding of protein dynamics and axonal transport in living cells. Key among these advances is the discovery that functional, fluorescent derivatives of many proteins can be expressed in living cells as protein fusions to green fluorescent protein (GFP). GFP, a protein from the jellyfish Aequorea victoria, generates a highly visible, efficiently emitting internal fluorophore. Using a hybrid of tissue plasminogen activator (tPA) and GFP, we have shown that tPA/GFP is transported in PC12 cells in secretory granules that accumulate in growth cones and that are released in response to secretatogues. Time-lapse images of the axonal transport of granules containing tPA/GFP reveal a surprising complexity to granule dynamics. Granules traffic bidirectionally along neurites and individual granules can reverse their direction of motion. The dynamics provide insight into the processes that power and coordinate the axonal transport of secretory granules.
Supported by NSF grant BIR-9510226.

341. BETWEEN SCIENCE AND TECHNOLOGY: DESIGNING A COST-EFFECTIVE GENETIC TEST FOR THE FRAGILE X SYNDROME. William N. Bloch, Perkin-Elmer Applied Biosystems, 850 Lincoln Center Drive, Foster City, CA 94404.

The fragile X syndrome, A site (FRAXA) is the most common form of inherited mental retardation, affecting on the order of 1/2000 of the population. It arises through inter-generational expansion of an unstable triplet repeat, (CGG/ CCG)n, on the X chromosome. Alleles of this triplet repeat fall into four functional size ranges: normal (5<n<45; no symptoms or instability), full expansion (200<n<2000; genetic instability and variable mental retardation), premutation (65<n<200; no clear symptoms, but variable expansion above 200 repeats during maternal transmission), and gray zone (45<n<65; no symptoms, and only slight inter-generational instability). Cost-effective genetic testing for FRAXA would support both the optimal treatment and training of developmentally delayed children (through differential diagnosis) and the prevention of disease, through pre-pregnancy or pre-natal genetic screening. It is important not only to determine who carries FRAXA full expansions, but also to advise women of risk for having mentally retarded children. The polymerase chain reaction (PCR) is the most economical method for FRAXA genotyping. However, it is rendered quite difficult by several features of this genetic locus: almost 100% GC content, very stable single-stranded secondary structure in the (CGG)n strand, and a serious "stutter" artifact. Scientific approaches to solving these problems will be described. In particular, the single-stranded secondary structure was found to depend on an easily controlled component of the PCR solvent.

342. CHARACTERIZATION OF A PEPTIDE DESIGNED FOR DE NOVO TRANSMEMBRANE TRANSPORT POWERED BY A pH-DIFFERENTIAL. Hong M. Moulton*, Paula I. Matthew, James E. Summerton, Patrick Iversen, Doreen Weller, and Dwight D. Weller, AVI Biopharma, 4575 SW Research Way Suite 200, Corvallis, OR 97333.

De novo-designed membrane transporter peptides were developed to transport molecules from endosomes to the cytosol of cells. These peptides reversibly change between a water-soluble form at neutral pH and a lipid-soluble form at acidic pH. They are shown to partition into an aqueous phase at neutral pH and an octanol phase at acidic pH. Circular dichroism studies indicate they are largely in random coil conformation at neutral pH and largely in a-helical conformation at acidic pH. Peptides of sufficient length move from an acidic aqueous compartment through a planar lipid bilayer membrane of phosphatidylcholine to a neutral aqueous compartment. Fluorescent microscopy and subcellular fractionation studies suggest these transporter peptides enter HeLa cells through endocytosis and then move from the endosomes to the cytosol. The capacity of these peptides to change from hydrophilic to lipophilic and back makes them ideal for transmembrane transport.

343. OPTIMIZATION IN PREPARATIVE CHROMATOGRAPHY: SEPARATION OF CHEMOTACTIC PEPTIDES. Sundar Ramanan and Ajoy Velayudhan*, Oregon State University, Department of Bioresource Engineering, Corvallis, OR 97331-3906.

Preparative chromatography is a vital, and often the most expensive, step in the purification of valuable biomolecules. Hence, optimization of the process variables in preparative chromatography is an active area of research. The conventional approach to optimization is based on analytical chromatography, and therefore attempts to optimize resolution. However, this approach significantly under uses the capacity of the column and consumes large quantities of mobile phase. Hence, in preparative chromatography, the objective function is productivity, which is a measure of maximum amount of feed that can be loaded on to the column while minimizing the separation time. Here, we report results from optimization studies carried out on a closely related binary peptide mixture (N-formyl-Met-Phe and N-formyl-Met-Trp) on an analytical reversed-phase column. The goal is to optimize productivity under the various chromatographic modes -- nonlinear isocratic elution, gradient elution, stepwise elution and displacement chromatography. In each mode, feed mixtures at the highest possible concentration (limited by solubility) were used. Productivity was monitored for increasing feed volumes. However, in some cases, solubility limitations from one of the feed components prevented further increase in loading. Even with this constraint, high productivities (5-10 g product/L stationary phase-h) were achieved. Independent experiments were carried out to measure the adsorption isotherms of these peptides over the range permitted by solubility. These isotherms were then coupled with the mass balance equation for each component and solved numerically. These predictive simulations were found to agree well with experiments.

344. A MOLECULAR DYNAMICS SIMULATION OF CHIRAL FLUIDS. Patrick B. Kohl and David L. Patrick*, Department of Chemistry, Western Washington University, Bellingham, WA 98225.

Molecular dynamics simulations were used to model a thin fluid film composed of molecules with a rigid head group and a flexible alkane-like tail group. In three dimensions the molecule is achiral, but when adsorbed to a surface, rotation about the bond linking the head to the tail is prevented, imparting a new chiral center to the molecule. This study examined whether or not reduced symmetry at an interface leads to a distinction between left- and right-handed configurations, and whether or not one of the two "enantiomers" is favored when the surface itself is chiral. Our findings indicate that chirality can be transmitted to the first layer of the bulk fluid. We discuss the effects of temperature, intermolecular interaction potential, and configuration of the adsorbed chiral layer on communication of chirality to the fluid. Much of the effect is attributed to an increase in the local orientational order parameter at the fluid-solid interface, leading to preferred molecular configurations with higher chirality. Connections can be made to a broad class of liquid crystal compounds, making these questions important for LC-based devices and applications such as chiral chromatography

345. MECHANISM AND KINETICS OF THE DEGRADATION OF THE CURARIMIMETIC DRUG SUCCINYLCHOLINE CHLORIDE. Kevin Hodges and Angela Hoffman*, Departments of Chemistry and Physics, University of Portland, Portland, OR 97203.

The purpose of this investigation was to determine the mechanism for degradation of succinylcholine chloride a rapid onset curarimimetic depolarizing agent used to facilitate paralysis. Succinylcholine is known to hydrolyze to the biologically inactive components, succinic acid and choline, via a highly temperature sensitive reaction. Succinylcholine vials are commonly disposed of after 15 days of non-refrigeration. Using high performance liquid chromatography and paper chromatography, this hydrolysis was found to result in an isolatable intermediate, succinylmonocholine, before ultimate degradation to succinic acid and choline. Kinetics of the hydrolysis at 5, 25 and 40°C was monitored using fluorescence spectroscopy and were found to follow zero-order kinetics. The results demonstrate that the recommended expiry is too conservative. If protected from light, storage at room temperature can be safely recommended with 95% chemical stability.

346. WHAT CONFERS INSECT-FEEDING RESISTANCE IN YEW? Lara Shamieh and Angela Hoffman*, Departments of Chemistry and Physics, University of Portland, Portland, OR 97203.

Yew plants are resistant to many forms of herbivory, including insect feeding. It is the goal of this experiment to determine which compound or compounds confer this resistance. Samples of Taxus x media 'Hicksii' were finely ground and extracted with methanol. The methanol extract was evaporated and the hexane-soluble compounds were removed. The aqueous solution was further purified with a C-18 Sep-Pak using methanol and the eluant was fractionated on an LH-20 column. Fractions were pooled based on electronic absorbance spectrophotometric (UV/VIS) analysis. After dilution to a constant volume with methanol, 20 µL of the samples were placed on tobacco leaves with young tobacco hornworms (Manduca sexta). Both the leaves and the worms were massed daily over a three-day period. The fraction with a major UV peak at 315 nm and also peaks at 345 nm, 370 nm, and 390 nm was 100% lethal in all replicates. This fraction was further separated using reverse phase HPLC at 315 nm. Eleven fractions corresponding t o major peaks were collected and tested using the hornworm bioassay. Two of these fractions were lethal in most replicates. These fractions were further purified by Silica gel thin layer chromatography (1:1 methanol and hexane).

347. ISOLATION AND STRUCTURAL ELUCIDATION OF BIOLOGICALLY ACTIVE COMPOUNDS IN CEASALPINIA BRASILIENSIS AND RHAMNACAE ZIZIPHUS OBTUSIFOLIA. Matthew Woll, Steven G. Wood, Du Li, and Noel L. Owen*, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602.

The objective of this project was to isolate, purify and identify biologically important compounds from the plants ceasalpinia brasilensis and rhamnacae ziziphus obtusifolia. Techniques such as liquid/liquid partitioning, open column silica gel chromatography, thin layer chromatography (TLC), and high pressure liquid chromatography (HPLC) have been employed to accomplish the isolation and purification of the compounds. Nuclear Magnetic Resonance Spectroscopy was the main tool used in the structural identification. The plant ceasalpinia brasilensis (commonly known as Palo de Brasil) is used in Puerto Rico as an anti-hypertensive drug. Several compounds have already been isolated from Palo de Brasil and their structures determined. This presentation focuses on isolating and identifying an unknown compound in Palo de Brasil that exhibits significant anti-hypertensive activity. Rhamnacae ziziphus obtusifolia, commonly known as graythorn, has been used as a cancer chemotherapeutic agent by the Yaqui Indians. Several compounds from graythorn that show activity against HeLa human cervical cancer cells have been isolated and purified.

348. FINANCIAL INVESTING FOR THE NOVICE AND MOST EXPERIENCED INVESTORS. Nancy Congdon, Field Vice President, American Express Financial Advisors, 10200 SW Greenburg Road, Suite 110, Portland, OR 97223.

With Nancy's candid, consumer-friendly approach, she will translate the language of investing into plain English for audiences from Main Street to Wall Street by tailoring and recommending individual needs and goals. She will detail when and how actions should take place and who is responsible for taking these actions. While Nancy will not create an inherent bias toward one type of investment over another, she will indicate sources of information and assumptions, and include both the pros and cons of any recommendations.

349. "CHEMISTRY" BETWEEN COMPANIES: MERGERS AND THEIR IMPACT ON YOU. Michael F. Spratt, Partner, PriceWaterhouseCoopers, 555 California Street, Suite 3600, San Francisco, CA 94104.

Dr. Michael F. Spratt, a partner with PriceWaterhouseCoopers global merger & acquisition consulting business and co-author of Five Frogs on a Log: A CEO's Field Guide for Accelerating the Transition in Mergers, Acquisitions and Gut Wrenching Change, will discuss how companies successfully navigate major transitions. Drawing on market surveys, research and client experiences, Dr. Spratt will outline tactics for avoiding the seven deadly transition sins as well as a strategy for stabilizing the organization, generating early momentum, and capturing early wins.

350. WHEN CHEMISTS "JUST DO IT": CUTTING-EDGE RESEARCH AT NIKE. Darcy Winslow, Director of Research and Development, NIKE, Inc., One Bowerman Dr., Beaverton, OR 97005.

Dr. Winslow will identify the importance of selecting and researching materials that not only affect the appearance of the shoe but the feel, comfort, and health of the human foot. By addressing these issues, she will provide an understanding of how research and development is as equally important as design and style, creating a whole new respect for the "Behind the Scenes" action in what we view as the "Action Sneaker" of today.

351. THE KYOTO GLOBAL WARMING TREATY - ECONOMICS AND POLITICS. Eban Goodstein, Department of Economics, Lewis and Clark College, Portland, OR 97219.

The Kyoto global warming treaty was signed by the United States last year. However prospects for ratification by the U. S. Senate are currently not favorable. This presents a social science puzzle. Relative to major U. S. environmental initiatives of the past, the elements appear to be in place for swift passage: there is relatively broad agreement in the science community that global warming is happening; the consequences look very ugly for lots of people and natural ecosystems; government analysts estimate we can meet the Kyoto targets at relatively low cost; and public opinion, by a large majority, supports action. The thesis of this talk will be that the missing piece is grassroots organization.

352. MOLECULE CORRALS: MONOLAYER AND MULTILAYER ETCHING, SELF-ASSEMBLY, AND NANOSTRUCTURE TEMPLATES. Forrest Stevens, Lisa A. Kolodny*, Jennifer A. McBride, and Thomas P. Beebe, Jr., Department of Chemistry, University of Utah, Salt Lake City, UT 84112.

Oxidation experiments using a particular grade of highly oriented pyrolytic graphite have allowed observation of large numbers of both monolayer and multilayer etch pits on the same samples, formed under identical conditions. Scanning tunneling microscopy was used to measure pits produced after various etch times, temperatures, and O2 pressures. From these data, pit growth rates, activation energies, and reaction orders were derived. Although multilayer pits were observed to grow over three times faster than monolayer pits in air, both types of pits had the same activation energy. Multilayer etch pits were sometimes observed to form at screw dislocations in the graphite, but were also seen in the absence of such defects. The experimentally determined reaction rates and activation energies were not consistent with a direct reaction of edge carbon atoms with atmospheric oxygen, but instead suggest a chain reaction or pre-equilibrium process. A mechanism for oxidation of multilayer pits involving reaction of partially oxidized sites on adjacent graphite layers is suggested. Additional uses of molecule corrals in studies of molecular self assembly, and as templates for nanostructure formation will also be presented.
# Visiting from Notre Dame University.

353. STRUCTURE AND MANIPULATION OF ISOLATED MOLECULES ON THE Pd(111) SURFACE. Miquel Salmeron, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.

Using a variable temperature (25-300K) scanning tunneling microscope, we have studied the structure and adsorption geometry of individual molecules adsorbed on Pd(111). The tip of the STM was also used to manipulate the molecules and to study the mechanism of interaction. The interactions included excitation of rotations (C2H2), displacements (O2, H, CO) and decomposition (O2 ¦ 2 O).

354. ADSORBATE MOLECULAR ORBITAL MEDIATED TUNNELING: SUB-MOLECULAR CONDUCTIVITY IN METAL PHTHALOCYANINES. Kerry W. Hipps* and Dan Barlow, Department of Chemistry and Materials Science Program, Washington State University, Pullman, WA 99164-4630.

The role of orbital mediated tunneling in metal-insulator-adsorbate-metal (M'-I-A-M) junctions will be briefly reviewed. The similarities between the M'-I-A-M junction and the STM environment will be stated. I-V and dI/dV data taken by STM from islands of VOPc on Au(111) will be presented. These data will be used to show that the same LUMO mediated tunneling seen in Al-I-MPc-Pb junctions is active in the STM environment, but shifted in position by the difference in work functions of Au and Pb. The local tunneling on a sub-molecular scale will also be considered. Images of several MPcs (M = Cu, Co, Fe, Mn, Ni, VO; all in the +2 state) will be contrasted. Included will be apparent height versus bias voltage studies. Finally, data suggesting that VOPc exists in two different conformations on the Au(111) surface will be presented. Finally, we present a simple model that provides estimates of the bias at which the onset of orbital mediated tunneling is observed for any substrate/adsorbate pair. Sub-molecular conductivity changes can also be predicted by this model.

355. INVESTIGATION OF THE EFFECTS OF SURFACE STRUCTURE ON THE INITIAL GROWTH OF ELECTROCHEMICALLY DEPOSITED METAL ON POLYCRYSTALLINE METAL FOILS. Kevin E. Johnson*, Max Montano, and Erik A. Syrstad, Department of Chemistry, Pacific University; Forest Grove, OR 97116.

Annealed polycrystalline metal foils exhibit faceting as observed by scanning tunneling microscopy (STM) in air. The orientation of each microcrystallite determines the degree of faceting. This characteristic of polycrystalline foils provides an opportunity to observe the effects of various initial surface morphologies on electrochemical deposition. Using STM we have measured the mesoscopic structure of initial growth of electrochemically deposited metals. We report studies comparing electrolytic versus electroless deposition, and deposition processes which lead to dendritic versus layered growth.

356. DIRECT COUNTING OF SOIL WAFERS - AN IMPROVED TOTAL ALPHA/BETA SCREENING ANALYSIS. R. W. Wong and S. B. Clark, Department of Chemistry, Washington State University, Pullman, WA 99164-4630 and W. C. Burnett, Environmental Radioactivity Measurement Facility, Department of Oceanography, Florida State University, Tallahassee, FL 32306-3048 and B. S. Crandall, Westinghouse Savannah River Company, Environmental Monitoring Section, Building 735-A, Aiken, SC 29808.

Currently applied "gross" alpha/beta analyses are often considered unreliable by the environmental monitoring community. We describe here an alternative approach based on direct counting of pressed soil "wafers" to estimate total alpha/beta activities. The system was calibrated using a series of natural standards with total activities estimated by a combination of available certified values, equilibrium assumptions, and our own measurements. Samples were prepared by mixing selected NIST and IAEA natural matrix standards with reagent grade cellulose in a 4:1 sample-to-binder ratio and pressing in a stainless steel die set. The resulting wafers were counted in a gas-flow proportional counter. Detection limits for this technique (alpha < 40 dpm/g, beta < 60 dpm/g) are within environmental levels commonly encountered in soils and sediments. This method should prove to be an inexpensive, simple, and waste-free approach for screening total radioactivity in soil samples.

357. ION-SELECTIVE POTENTIOMETRY IN NATURAL WATER BODIES AND PRESSURIZED PROCESS FLOWSTREAMS. Stephen H. Hall, Instrumentation Northwest, Inc., 1925 West 16th Avenue, Kennewick, WA 99337.

Many ion-selective sensing electrodes can be used without sample pretreatment and can in principal be submerged and used for real time in situ measurements in wells, surface water bodies, and process flowstreams, where ambient pressure is significantly greater than one atmosphere. Until recently, practical in situ use has been limited to pH and Eh measurement, but new techniques and instrument design now enable general in situ determinations with accuracy comparable to that of direct potentiometry as performed in the laboratory, and with instrument stability that is measured in weeks or months, depending upon environmental conditions. The four main improvements that make this possible are (1) a reference electrode that is pressure-independent, but retains the stability and Nernstian behavior of laboratory-type free-flowing electrodes; (2) a general method for temperature compensation; (3) a practical approach for ionic strength matrix matching; and (4) a signal preamplifier that minimizes the effect of environmental electrical noise.

358. CORRELATION OF ERGOVALINE AND LOLITREM B LEVELS IN PERENNIAL RYEGRASS. Jeannette T. Hovermale* and A. Morrie Craig, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331.

Perennial ryegrass which is infected with the endophytic fungus Neotiphodium lolii contains several classes of toxic alkaloids, including ergopeptide and lolitrem alkaloids. Lolitrem B, a potent tremorgen, is considered to be the predominant alkaloid in endophyte infected perennial ryegrass. Ergovaline, a vasoconstrictor normally associated with endophyte infected tall fescue, is also present in endophyte infected perennial ryegrass. A survey performed on perennial ryegrass straw determined the levels of both alkaloids in the straw. All perennial ryegrass straw samples received at the Oregon State University Veterinary Diagnostic Laboratory between March and August 1998 were analyzed for each alkaloid using HPLC analysis. Over 400 samples were analyzed for this survey. A strong correlation was observed, especially in samples containing less than 3000 ng/g lolitrem B. The threshold levels above which clinical symptoms typically occur is 2000 ng/g lolitrem B and 500 ng/g ergovaline. All of the samples analyzed contained less than 500 ng/g ergovaline.

359. DECHLORINATION OF DDT BY MAGNESIUM/PALLADIUM BIMETALLIC PARTICLES. John G. Doyle, I. Francis Cheng*, Mark D. Engelmann, and Kristy Henscheid, Department of Chemistry, University of Idaho, Moscow, ID 83844-2343.

The dechlorination of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) at standard temperature and pressure by a magnesium/palladium bimetallic system has been demonstrated. The process is both rapid and thorough attaining complete dechlorination (within the detection limit of GC-MS) of 300 ppm DDT in less than fifteen minutes. The simplicity and efficiency of this system compared with the limited success attained by other methods demonstrates great promise for both the quantification and remediation of this high priority contaminant.

360. ELECTRONEGATIVITIES FROM CORE-IONIZATION ENERGIES: SF5 AND CF3. Darrah Thomas*, Gary L. Gard, Paul Nixon, Robin Terjeson, Jan True, and Rolf Winter, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003 and Department of Chemistry, Portland State University, Portland, OR 97207-0751.

For halogenated methanes, ethanes, and ethenes there is an excellent linear correlation between the C 1s ionization energies and the electronegativities of the ligands attached to the carbon. This is used together with measured core-ionization energies of compounds containing SF5 and CF3 to determine the electronegativities of SF5 and CF3. These are found to be approximately the same as that of Br. Measurements of S 2p and Br 3d ionization energies lead to the same conclusions. These results are completely at odds with those of other methods of estimating electronegativities, which generally agree that the electronegativities of CF3 and SF5 are between those of Cl and F. Reasons for this disagreement will be considered and the differences between the behavior of CF3 and SF5, on the one hand, and F, on the other, will be discussed.

361. STUDIES OF ANION SEPARATIONS USING CALIXARENES WITH PENDANT METAL REDOX CENTERS. Gregory M. Anderson1, Timothy L. Hubler*1, Johanes H. Sukamto1, A. L. Rheingold2, L. Liable-Sands2, and T. Concolino2, 1Pacific Northwest National Laboratory, P.O. Box 999, MS K8-93, Richland, WA 99352 and 2Department of Chemistry, University of Delaware, Newark, DE 19716.

We have investigated the anion separation potential of metallocene-substituted calixarenes. Metallocene esters (ferrocene and cobalticenium) were synthesized with p-tert-butylcalix[4]arene, p-tert-butyloxacalix[3]arene, and other phenolic compounds. The anion selectivity of the new compounds with respect to chloride, nitrate and perrhenate was studied using cyclic voltammetry. A mono-ferrocene ester of p-tert-butylcalix[4]arene may show some minor selectivity for nitrate ion over perrhenate ion.

362. SEASONAL TRENDS IN STRONG COPPER BINDING LIGANDS IN TWO NEW ZEALAND LAKES. Jonathan P. Kim and Keith A. Hunter, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand.

The chemical speciation of copper (Cu) in two New Zealand lakes on the South Island, New Zealand has been investigated. The presence of strong Cu-binding ligands in surface waters was observed on a seasonal basis for both Lakes Manapouri and Hayes. The ligand concentrations, in the nanomolar (nM) range, were comparable to those observed in the open ocean, but had higher binding constants (K'). For L. Manapouri, high ligand levels occurred during the Austral spring and fall. However, during summer the ligand concentration became very low, resulting in free Cu2+ concentrations that were high enough to inhibit phytoplankton growth. Therefore, phytoplankton activity may be mediating the production of the strong Cu-binding ligand. The strong ligand concentration, during the summer, increased with depth in both lakes, which may be due to remineralization of organic matter in the benthos. Further detailed studies are needed to elucidate the mechanisms responsible for the production of the strong Cu-binding ligand in these lacustrine systems.

363. FORMS OF MERCURY AND BIOACCUMULATION OF MERCURY IN LONG-FINNED EELS, ANGUILLA DIEFFENBACHII, FROM THREE RIVERS IN OTAGO, NEW ZEALAND. Amanda C. Redmayne, Jonathan P. Kim, Gerry Closs, and Keith A. Hunter, Departments of Chemistry and of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.

The suitability of the New Zealand long-finned eel (Anguilla dieffenbachii) as a biomonitor of mercury was investigated. Total mercury and methylmercury were determined in the tissue of eels from three similar-sized rivers in Otago, New Zealand: the Water of Leith (urban catchment), the Flemming River (native bush catchment), and the Kyeburn River (pastoral and gold mining catchment). The growth rates of the eels from the Water of Leith and Kyeburn River (3.17 ± 0.41 cm year-1 and 3.00 ± 0.37 cm year-1; mean ± 1 SD) were higher than that of the eels from the Flemming River (1.40 ± 0.40 cm year-1). On average, 84% of the total mercury in eel tissue was in the form of methylmercury. The concentration of methylmercury in eel tissue increased with age, length, and mass. However, there was a significant difference (p < 0.001) in the rate at which methylmercury was accumulated in the eels (Kyeburn River: 13.0 ± 5.6 ng g-1 year-1; Water of Leith: 3.6 ± 0.7 ng g-1 year-1; Flemming River: 2.6 ± 2.0 ng g-1 year-1). These differences are probably due to a combination of factors, including the concentration of mercury in the water and local bedrock, eel growth rate, the structure of the food web and the chemical background of the river.

364. PREPARATION OF HEXA(METHYLHYDROQUINONE)CYCLOTRIPHOSPHAZENE AND SUBSTITUTION REACTIONS WITH ALKYL HALIDES. Thomas A. Luther* and Frederick F. Stewart, Idaho National Engineering and Environmental Laboratory, Lockheed Martin Idaho Technologies Company, P.O. Box 1625, Idaho Falls, ID 83415-2208.

The preparation of a new cyclotriphosphazene monomer has been accomplished by the reaction of methylhydroquinone with hexachlorocyclotriphosphazene in cyclohexane solvent using 4-picoline as a base. Unlike what has been recently reported for the analogous reaction with tert-butylhydroquinone, the NMR data indicate that the methyl group of the methylhydroquinone does not enforce orientation of the methyl group completely away from the phosphorus-nitrogen ring in the substitution process. Additionally, substitution reactions using these cyclotriphosphazenes with a series of alkyl halides to generate ethereal pendant groups will be discussed.

365. MATRIX AND SOLUTION PHOTOCHEMISTRY OF Rh(CO)2LCl, WHERE L = AMINE OR PYRIDINE. Thomas Bitterwolf* and B. Scallorn, Department of Chemistry, University of Idaho, Moscow, ID 83844-2343.

While considerable effort has gone into the study of the photochemistry of rhodium carbonyl phosphine compounds, Rh(CO)(PR3)2Cl, no work has been reported on the photochemistry of the amine and pyridine derivatives, Rh(CO)2LCl. Investigation of the photochemistry of these compounds in frozen Nujol matrices established that CO loss is the dominant photoprocess yielding photoproducts with CO trans to either Cl or the nitrogen ligand. Interestingly, solution photolysis of these monosubstituted compounds in the presence of an excess of ligand yields the previously unknown Rh(CO)L2Cl derivatives.

366. KINETICS AND MECHANISM OF LIGAND SUBSTITUTION REACTIONS OF (INDENYL)M(CO)4 AND CpM(CO)4, WHERE M = Nb OR Ta. D. Lukmanova and Thomas Bitterwolf*, Department of Chemistry, University of Idaho, Moscow, ID 83844-2343.

Kinetic studies were preformed for CO substitution reactions of CpM(CO)4 and IndM(CO)4 with phosphines and phosphites. In contrast to earlier literature reports, the unsubstituted CpM(CO)4 (M = Nb and Ta) compounds were found to undergo substitution by a purely dissociative mechanism. Ligand exchange of the indenyl derivatives was found to be associative indicating that an "indenyl" effect is operative in this series of compounds.

367. ADSORPTION AND DESORPTION KINETICS OF HYDROGEN SULFIDE ON Au{100} AND Ag{111}: IMPLICATIONS FOR SELF-ASSEMBLY. St. John Dixon-Warren* and Yan Yu, Department of Chemistry and Program in Materials Science, Washington State University, Pullman, WA 99164-4630.

The adsorption and desorption of hydrogen sulfide on Au{100} and Ag{111} has been studied using a combination of surface science techniques, including temperature programmed desorption (TPD), low energy electron diffraction, Auger electron spectroscopy and reactive molecular beam scattering. The results show marked differences between the adsorption and desorption kinetics of the hydrogen sulfide on clean Au{100}-(5x20) and sulfur covered Au{100}-(1x1)-SH. The sulfur covered surface was prepared by electron induced decomposition of pre-adsorbed hydrogen sulfide. At 80K clean Au{100}-(5x20) exhibits precursor mediated adsorption kinetics while the sulfur covered gold surface exhibited Langmuir kinetics. The TPD shows hydrogen sulfide does not chemisorb on the clean (5x20) surface, which appears to be inert. Dissociative chemisorption to yield adsorbed HS fragments appears to occur on the electron irradiated Au{100}-(1x1)-SH

368. PEPTIDES AND POLYMERS: INTERFACIAL MOLECULAR ARCHITECTURE FOUNDED ON TERMINALLY FUNCTIONALIZED SELF-ASSEMBLED MONOLAYERS. Glen E. Fryxell*, Kentin Alford, Kevin Simmons, William D. Samuels, Peter C. Rieke, Liang Liang, and Manish Shah, Pacific Northwest National Laboratories, P.O. Box 999, Richland, WA 99352.

Covalent attachment of a material to a solid surface is desirable for a wide variety of applications; molecular recognition studies, sensor design, composite material synthesis or surface property manipulation. We have used terminally functionalized self-assembled monolayers (SAMs) as a foundation upon which to build chemically elaborate interfacial architectures. To this end, we have anchored peptides, oligonucleotides, pharmaceuticals, oligomers, polymers, initiators and curing agents to various SAM interfaces and examined their behavior. Ellipsometry, fluorescence, dynamic wetting angle measurements and electron microscopy (among others) were routinely employed to monitor attachment of these materials to the monolayer interface. Some of the useful properties (antimicrobial activity, composite material enhancement, interfacial wettability control, etc.) of these functionalized organic thin films will be summarized.

369. GROWTH UNIFORMLY ORIENTED MOLECULAR FILMS USING LIQUID CRYSTAL ANCHORING INTERACTIONS. David L. Patrick*, Joseph D. Mougous, Robert T. Baker, Andrew Barckley, Douglass M. Scott, and Katherine M. Foland, Department of Chemistry, Western Washington University, Bellingham, WA 98225.

Organic thin films possessing uniform crystallographic orientation over microscopic to macroscopic length scales have been prepared by depositing material from a liquid crystal (LC) fluid onto a solid substrate in the presence of an external alignment field. We show that orientational order at the solid-fluid interface originates during film nucleation, and is controlled through anisotropic anchoring interactions between surface adsorbates and the LC solvent. Details of the relationship between molecular-scale surface structure and bulk LC ordering were studied by combining scanning tunneling microscopy and polarized optical measurements of uniformly oriented cells. These findings reveal the microscopic origins of the surface memory effect, and suggest a new method for the controlled synthesis of uniformly ordered nanostructured materials.

370. INVESTIGATIONS OF STABILITY IN HYDROGEN-BONDING SELF-ASSEMBLED MONOLAYERS. Rachel K. Smith, Robert S. Clegg, Athena Klock, and James E. Hutchison*, Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403-1253.

The thermal and solvent stability of self-assembled monolayers (SAMs) directly affects their ability for application in developing materials for chemically modified surfaces used in practical technologies. Incorporating internal functionalities into ordered (SAMs) is a likely way to enhance their stability in such cases. We are presently studying the stabilities of amide-substituted alkanethiols adsorbed onto gold substrates by employing a quartz crystal microbalance. These internal amide groups are located close to the thiol moiety and hydrogen bond extensively; these amide-containing adsorbates have been synthesized in such a manner that one to three amide groups are included. The relative stabilities of monolayers containing one, two, and three amide groups upon exposure to a variety of solvents will be presented.

371. PROBING MONOLAYERS OF 4-AMINOPHENYL PHOSPHONIC ACID USING SECOND HARMONIC GENERATION. Elizabeth L. Hommel, Rebecca S. Hamblin, Greg M. Lowmann, and Catherine J. Page*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Self-assembled organic-inorganic multilayer thin films are desirable for various applications, since the properties are controlled through careful selection of the compounds incorporated into the multilayer structure. We are studying these types of self-assembled multilayer thin films for possible application as non-linear optical (NLO) materials. Techniques such as x-ray photoelectron spectroscopy and ellipsometry confirm multilayer growth, and second harmonic generation (SHG) is used to characterize the NLO response of the multilayer thin films. The system currently under investigation is a superstructure, which incorporates 4-aminophenyl phosphonic acid as the NLO-active moiety. The SH experiments not only measure NLO activity, but also provide insight into the structure and growth of the multilayers.

372. PHOTOPATTERNING THIN FILM MULTILAYERS. Andrea D. Sieg, Elizabeth L. Hommel, and Catherine J. Page*, Department of Chemistry, University of Oregon, Eugene, OR 97403.

Layer-by-layer assembly of multilayer thin films allows controlled growth of multiple layers in the direction perpendicular to the substrate. To control growth in the lateral direction, we are investigating patterning planar surfaces using UV lithography. Patterning is accomplished via UV-initiated phosphonation of an aryl iodide monolayer on a silicon wafer. Hydrolysis of the phosphonated areas to give phosphonic acid moieties allows for sequential growth of metal bisphosphonate multilayers by self-assembly. The thickness of the metal bisphosphonate regions can be controlled by varying the number of self-assembled metal bisphosphonate layers. Thorough analysis of this experiment using ellipsometry and x-ray photoelectron spectroscopy (XPS) provides insight into the photochemistry taking place upon exposure to UV light.

373. SPECTROSCOPIC AND MICROSCOPIC STUDIES OF METAL PHTHALOCYANINE LANGMUIR-BLODGETT FILMS. Ursula Mazur* and Naoko Miyashita, Department of Chemistry and Materials Science Program, Washington State University, Pullman, WA 99164-4630.

Monolayers of para-octa-butoxy copper(II) phthalocyanine (CuPCB) were prepared by the Langmuir-Blodgett technique. Mica and glass substrates were employed. FT-IR and UV-Vis spectroscopies as well as SFM (Scanning Force Microscopy) were used to study the films' molecular structure and orientation. It was determined that CuPCB LB films are stable and show no degradation or structural changes over periods of days. Surface pressure vs. area per molecule isotherms and SFM images confirm that the CuPCB molecules in the LB monolayer are oriented with the phthalocyanine ring parallel to the surface. The SFM studies also indicate that the CuPCB LB monolayer consists of large islands. The size of these islands depends on the substrate dipping speed and the LB film transfer ratio.

374. ARTIFICIAL LIGHT-DRIVEN CYCLIC TRANSMEMBRANE ELECTRON-PROTON PUMP. R. F. Khairutdinov and James K. Hurst*, Department of Chemistry, Washington State University, Pullman, WA 99164-4630.

Prospects for developing integrated chemical systems designed to perform specific tasks rest upon devising simple robust molecules that can perform multiple functions. In this presentation, we will describe the chemical reactivity of an organic ion that can act both as a redox mediator in photoinitiated electron transfer reactions and as a cyclic transmembrane cotransporter of protons and electrons. This or similar ions may be useful in membrane-based devices for photocatalytic solar energy conversion or similar high-flux applications. The photochemical reaction system that we have been investigating consists of vectorially organized dihexadecyl phosphate (DHP) small unilamellar vesicles containing three components in the external bulk phase--an anionic water soluble zinc porphyrin, either 2,4,6-trimethylpyrylium or 2,4,6-triphenylpyrylium ions, and the electron donor, dithiothreitol--with the electron acceptor, Co(bpy)33+(bpy = 2,2'-bipyridine), occluded within the inner aqueous phase. Photoexcitation of the zinc porphyrin with visible light led to efficient oxidative quenching by the pyrylium ions, following which the neutral pyrylium radical diffused across the bilayer membrane, delivering an electron to the acceptor. Subsequent hydrolysis of the internally localized oxidized pyrylium ion formed a diketone, which was accompanied by release of a proton. The uncharged diketone then diffused back through the membrane into the bulk solution, where it underwent ring-forming restoration of the pyrylium ion, thus closing the cycle of mediator transformations. The electron-proton pumping efficiency was about 100% over more than 23 pumping cycles. Individual reaction steps were probed by transient spectrophotometry using the frequency doubled and tripled lines of a pulsed Nd:YAG laser.

375. 1-(CARBOXYMETHYL)-4-CYANOPYRIDINIUM-MEDIATED PHOTOINDUCED ELECTRON-PROTON COTRANSPORT ACROSS DIHEXADECYLPHOSPHATE VESICLE MEMBRANES. L. D. Lucchesi and James K. Hurst*, Department of Chemistry, Washington State University, Pullman, WA 99164-4630.

There is presently considerable interest in developing integrated chemical systems for photogeneration of fuels, e.g., photocatalytic water splitting to H2 and O2. One promising approach, which is a focal point of our laboratory, is to organize photoinitiated reactions around closed bilayer membranes (vesicles). A major technological problem that has not been addressed so far in these systems is that the electron carrier is generally membrane-diffusible in only one oxidation state. As a consequence, it accumulates within the vesicle and the system ceases to function. To overcome this problem, we have been devising molecules that are capable of cyclically co-transporting protons and electrons, somewhat analogously to quinone/hydroquinone couples in living cells. Results will be presented of our ongoing investigations on the capabilities of 4-cyanopyridinium analogs bearing carboxyalkyl substituents attached to the ring nitrogen atom to act as combined oxidative quenchers/proton-electron cotransporters in vectorially organized vesicular systems. Because they are formally uncharged both as the 1-carboxyalkylpyridinium zwitterion and the one-electron reduced pyridinium radical at appropriate pH values, these redox mediators can potentially cycle between the inner membrane and bulk aqueous phases.

376. THE CHEMISTRY AND BIOCHEMISTRY OF GUANINE OXIDATION IN DNA AND RNA. Cynthia J. Burrows*, James G. Muller, Robyn P. Hickerson, Victor Duarte, Wenchen Luo, and Olga Kornyushyna, Department of Chemistry, University of Utah, Salt Lake City, UT 84112-0850.

Guanine is the nucleobase most susceptible to oxidative damage in DNA. One-electron oxidation of G can be effected by a variety of radical, transition metal, and photochemical methods leading to a cascade of products. One common oxidation product in damaged DNA is the nucleobase 8-oxoguanine. This base is in turn more easily oxidized that G. We have examined the products of G and 8-oxoG oxidation, their mutagenic potential as measured by nucleotide misinsertion with polymerases, and the structural requirements for facile oxidation. Oxidation of G in RNA in certain structural motifs can also lead to damage at neighboring sites. The implications of the organic mechanisms of oxidation for mutation, DNA repair and structural biology will be presented.

377. CHEMICAL AND MUTAGENIC INVESTIGATIONS OF FATTY ACID AMIDE HYDROLASE: EVIDENCE FOR A FAMILY OF SERINE HYDROLASES WITH DISTINCT CATALYTIC PROPERTIES. B. F. Cravatt, Matthew P. Patricelli, and Martha A. Lovato, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037.

Fatty Acid Amide Hydrolase (FAAH) is a membrane-bound enzyme responsible for the catabolism of neuromodulatory fatty acid amides, including anandamide and oleamide. FAAH's primary structure identifies this enzyme as a member of a diverse group of alkyl amidases, known collectively as the "amidase signature family". At present, this enzyme family's catalytic mechanism remains poorly understood. In this study, we investigated the catalytic features of FAAH through mutagenesis, affinity labeling, and steady state kinetic methods. In particular, we focused on the respective roles of three serine residues that are conserved in all amidase signature enzymes (S217, S218, and S241 in FAAH). Mutation of each of these serines to alanine resulted in a FAAH enzyme bearing significant catalytic defects, with the S217A and S218A mutants showing 2300- and 95-fold reductions in kcat, respectively, and the S241A mutant exhibiting no detectable catalytic activity. Affinity labeling of FAAH with a specific nucleophile reactive inhibitor, ethoxy oleoyl fluorophosphonate, identified S241 as the enzyme's catalytic nucleophile. Interestingly, mutation of each of FAAH's conserved histidines generated active enzymes, indicating that FAAH does not contain a Ser-His-Asp catalytic triad commonly found in other mammalian serine hydrolytic enzymes. The unusual properties of FAAH identified here suggest that this enzyme, and possibly the amidase signature family as a whole, may hydrolyze amides by a novel catalytic mechanism.

378. SPECTROSCOPIC AND KINETIC CHARACTERIZATION OF SOYBEAN AND HUMAN LIPOXYGENASE. Ted Holman*, Evan R. Lewis, and Eric Johansen, Chemistry Department, University of California, Santa Cruz, CA 95064.

Lipoxygenases are an important class of non-heme iron enzymes which catalyze the hydroperoxidation of unsaturated fatty acids. In this abstract, we will discuss the use of electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD), in order to probe the ground state and excited states of the active site of an iron coordination mutant of soybean lipoxygenase-1 (SLO-1), N694H, and relate the structural modifications with kinetic changes. In addition, we will discuss a novel competitive RF-HPLC method to determine the kinetic isotope effect for 15-human lipoxygenase (15-HLO). This novel method establishes that the KIE for 15-HLO is large and temperature independent above ~ 20°C (KIE ~ 50) which indicates the reaction is rate limited by C-H cleavage and that the large KIE is due to hydrogen atom tunneling. Therefore, hydrogen atom tunneling should now be considered a common characteristic of this enzyme class of lipoxygenases.

379. REGULATION OF SONIC HEDGEHOG PROTEIN LEVELS IN CULTURED CELLS BY CHOLESTEROL DEPRIVATION. Rodney K. Guy, Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143.

Sonic hedgehog (Shh) is a signaling molecule that plays an early and central role in the patterning of the developing vertebrate central nervous system. During its posttranslational processing and secretion, Shh undergoes an autoproteolytic reaction with a concomitant covalent attachment of cholesterol to the newly formed carboxyl terminus of the signaling portion of the molecule. Smith-Lemli-Opitz (SLO) holoprosencephaly can be caused by lack of a functional 7-dehydrosterol reductase. In these patients, severity of disease is inversely correlated with fetal blood cholesterol levels. It has been hypothesized that this form of holoprosencephaly could be caused by a suppression of hedgehog processing by cholesterol deprivation. We have shown that acute severe cholesterol deprivation in cultured cells expressing mouse Shh does indeed kinetically inhibit the autoprocessing reaction of Shh. Furthermore, when Shh autoprocessing is suppressed in these cells, the precursor form of Shh is retained in an intracellular compartment and degraded. Thus the kinetic block enforced by cholesterol deprivation prevents the steady state accumulation of the mature, extracellular form of mShh. These observations directly support the hypothesis that cholesterol deprivation induced perturbation of Shh function could be a contributing factor to SLO holoprosencephaly.

380. A GENETICALLY ENGINEERED MOUSE WITH A HUMAN ANTIBODY REPERTOIRE. Nils Lonberg, GenPharm, 2350 Qume Drive, San Jose, CA 95131-1807.

Approximately one-third of all therapeutic biotechnology products under development are monoclonal antibodies originally derived from rodents. The technology for obtaining high affinity, high specificity, rodent monoclonal antibodies is well established; however, these molecules elicit a strong immune response when administered to human patients. To minimize this intrinsic immunogenicity, several new molecular biology-based technologies have been employed to generate monoclonal antibodies that are as close as possible to natural human antibodies. We have developed a transgenic mouse system that directly generates human monoclonal antibodies. This system consists of a mouse strain that has been genetically engineered, using a combination of pronuclear microinjection and homologous recombination in embryonic stem cells, so that human immunoglobulin gene loci functionally replace the endogenous mouse immunoglobulin gene loci. These mice respond to foreign antigens with the expression of human rather than mouse antibodies. We have used these mice to isolate a large number of different human monoclonal antibodies, including several therapeutic candidates, one of which is now being tested in patients. The kinetic and equilibrium binding properties of these human antibodies are characteristic of natural high affinity mouse monoclonal antibodies, while the immunogenic properties are characteristic of natural human antibodies.

381. MORPHOLINO OLIGOMERS AS ANTISENSE AGENTS. Ron I. Sato, Dwight D. Weller, Christina M. Fox, Doreen D. Weller, Murali T. Reddy, Pat L. Iversen, and Jim E. Summerton, AVI BioPharma, 4575 SW Research Way, Suite 200, Corvallis, OR 97333-1063.

Fifty year ago, when Watson & Crick resolved Rosalind Franklin's x-ray of the fibers of B form DNA into the antiparallel double helix, they created not only the most recognized icons of the half century, they gave chemists a powerful structural motif to intercede in a cell's behavior. A strategy derived from Crick's "Central Dogma"--construction of a sequence of nucleotides binding a critical "message" strand, thereby interfering with translation--is commonly known as "antisense". Traditional "pharmaceutical" problems must be surmounted, viz. ADME, before these agents can be administered therapeutically. AVI BioPharma has developed a proprietary backbone structure which successfully deals with many problems arising during realization of this approach to the therapeutic modulation of pathology. The pharmacologic advantages for this prototypical structure will be cited as will its preparation via solid phase synthesis. Progress through the regulatory aspects of the drug development process toward the control of post-angioplasty restenosis will also be presented.

382. PLASMA-SYNTHESIS OF COMPOUND LIBRARIES FOR DRUG DISCOVERY. Bruce M. Johnson, Teri A. Miles, David R. Kamperman, Walter C. Babcock, and James B. West, Bend Research, Inc., Bend, OR 97701 and Fred W. Berman and Thomas F. Murray, Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602 and Inder Pal Singh and William H. Gerwick, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

It has long been known that reaction of vaporized organic compounds can be induced by plasmas (partially ionized gases). Interest peaked in this area during the period from about 1950 to 1975 and then quickly waned due to the inherent problems of poor compound yield and the production of complex product mixtures. With the development of high-throughput-screening methods for drug discovery and the attendant need for ever-increasing numbers of test compounds, the inherent problems of the plasma-synthesis process can be turned to an advantage. We have shown that proper reactor design, and the judicious selection of reactants, can produce chemical libraries containing approximately 50 to 200 principal compounds in a single reaction. Many of these compounds exhibit the physical and chemical characteristics of pharmaceuticals and contain a wide array of structures that are not limited to the normal thermal-chemistry reaction routes. Most importantly, many of the libraries have shown unusually high activity toward opioid (kappa), cannabinoid (CB-1), and adenosine (A1) receptors. We will present our results to date and briefly describe the technical challenges that must be met to develop a mature plasma-synthesis technology for preparing, isolating, and identifying new bioactive compounds.

383. HOMOLOGOUS CLONING OF FUNGAL CELLULASE CHROMOSOMAL LOCI: A RAPID ROUTE TO CATALYST DIVERSITY. Scott D. Power*, Colin Mitchinson, Andrew Shaw, Frits Goedegebuur, Pim v. d. Kley, Piet v. Solingen, Lydia Dankmeijer, Hesselein Riel, Jay Phillips, and Tim Fowler, Genencor International, Palo Alto, CA 94304-1013 and Leiden, The Netherlands.

Cellulases, as enzymes for the degradation and modification of biomass, have been at the forefront of biotechnology for the past 15 years. With the emergence of new high throughput PCR-cloning techniques, it is now possible to rapidly sample the evolutionary diversity of a particular catalyst backbone even in fungal systems. When coupled to high resolution x-ray crystallography, the resulting database of structural information permits rapid protein engineering of the backbone. A discussion of our efforts on mapping the diversity of the Family 12 endoglucanase, Trichoderma resei endoglucanase III, throughout diverse fungi will be presented.

384. MOLECULAR STUDIES OF THE ROLE OF ETHYLENE IN POTATO (SOLANUM TUBEROSUM L.) TUBER DORMANCY RELEASE. Margo M. Haines*1, Patrick J. Shiel1, Philip H. Berger1, and John K. Fellman2, 1 Plant, Soil, and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339 and 2 Horticulture and Landscape Architecture, Washington State University, Pullman, WA 99164-6414.

Ethylene is a gaseous plant growth regulator implicated in all stages of plant development including seed dormancy and germination. Dormancy in stored potatoes is under study to reduce dependency on chemical inputs and improve availability of raw product for the processing industry in the Pacific Northwest. To investigate the role of ethylene in potato (Solanum tuberosum L.) dormancy release, we infected potato and tobacco (Nicotiana tabacum L.) with Agrobacterium tumefacians previously transformed with the Arabidospsis etr1-1 gene, which codes for a putative, dominant, mutant ethylene receptor. Sense and antisense constructions of etr1-1 were introduced under the control of a constitutive 35S promoter and a sucrose-inducible, tuber-specific promoter. After selection of transformed plants on sucrose and kanamycin, plants were rooted and propagated via cuttings. Transformed plants containing the sense construction of etr1-1 under both the 35S constitutive promoter and the sucrose-inducible, tuber-specific promoter had phenotypic abnormalities including flattened stems, small leaves, chlorotic leaves and a flattened stem with a curvature resembling a "hook". The effect of sense and antisense constructions of etr1-1 under the control of constitutive and inducible promoters on the overall plant phenotype, the possible lethal consequence of such constructions, and the potential to affect tuber dormancy are discussed.

385. PROCESSING AND CHARACTERIZATION OF POROUS CERAMIC SCAFFOLDS. Susmita Bose,* Jens Darsell, Li Hua,** Dipak Sarkar** and Amit Bandyopadhyay, School of Mechanical and Materials Engineering, Washington State University and **Department of Veterinary Medicine, Washington State University, Pullman, WA 99164.

Fused deposition (FD), a commercially available rapid prototyping process, is used for the fabrication of controlled porosity alumina ceramic scaffolds. Polymeric molds having desired porous structures were fabricated using FD. The molds were then infiltrated with alumina ceramic slurry, dried and subjected to a binder removal and sintering cycle to form the controlled porosity alumina ceramic scaffolds. Porous structures were coated with bioactive ceramic and polymer. In vitro biological responses of these materials were assessed. Comparative studies were carried out with alumina and alumina coated hydroxyapatite (HAp) and alumina coated poly-levo-lactic acid (PLLA) systems. Biomechanical tests were also conducted with scaffolds before and after in-vitro testing. The presentation will include preparation, biocompatibility and biomechanical studies of novel porous ceramic scaffolds.

386. DEVELOPMENT AND STUDENT USE OF WEB-BASED PRELABS. Brian M. Tissue, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061.

I will report on four years of student use of Web-based prelabs in senior-level Instrumental Analysis. The prelabs consist of text and graphical tutorials, interactive instrument tours, and multiple-choice self-evaluation questions. (Examples of clickable image maps, JavaScripts, and PERL scripts are at http://www.chem.vt.edu/chem-ed/ .) Student and instructor perceptions indicate that the prelab assignments help prepare students for their lab work. However, the overall effectiveness of the prelabs depends on changing student attitudes and behavior so that students take greater responsibility for their own lab preparation and outcomes. Using these prelabs has made evident the challenge of teaching students to effectively use all available learning aids: lectures, lab work, multimedia, and textbook.

387. CHEMVISU - TEACHING CHEMISTRY WITH HYPERACTIVE MOLECULES. Marco Ziegler, University of California, Berkeley, Department of Chemistry, Berkeley, CA 94720-1460.

Molecules and chemical reactions can be conveniently displayed in a web-browser in 3D with the help of a number of available techniques (VRML, plug-ins, OLE links) which allow programmed and non-programmed interaction with the user. The use of such techniques for teaching and examinations will be outlined. A small collection of examples is available at http://sgich1.unifr.ch/chemvisu.html .

388. THE MERL CD-ROM: USING IRON PERMEABLE REACTIVE BARRIERS TO TEACH CHEMISTRY. David J. Severson1, Theron Morgan-Brown1, Barbara A. Balko*1, and Paul G. Tratnyek2, 1Department of Chemistry, Lewis and Clark College, Portland, OR 97219 and 2Department of Environmental Science and Engineering, Oregon Graduate Institute, Portland, OR 97291.

We are developing a CD-ROM to introduce students and teachers to the chemistry involved in permeable reactive barriers (PRBs) composed of iron particles. Iron PRB technology, which is currently used to reduce halocarbon contaminants in groundwater, provides an excellent teaching opportunity for two reasons. First, the environmental nature of the material interests most students. Second, the technology illustrates concepts from several fields of chemistry (namely environmental, organic, physical, and inorganic), many of which can be discussed at a range of levels. The CD-ROM format makes it possible for users to proceed through the material according to their own abilities and interests and allows us to use various media (including animations, surface images, video footage, and graphing programs) to illustrate the chemical concepts.

389. CHEMISTRY EDUCATION AND THE INTERNET. Carol A. Handy, Portland Community College, PO Box 19000, Portland, OR 97280-0990.

How can the Internet facilitate chemistry education? At Portland Community College we are using the Internet in the chemistry department. A web page was prepared for several chemistry classes as an OCEPT project. The purpose of the webpage is to provide the students quick access to the syllabus, the lab schedule, the homework assignment, the reading assignment, past exams, and other information pertaining to their chemistry class. The Organic Chemistry class is involved in a special project, also supported by OCEPT, that involves medicinal plants found on the Sylvania campus. The webpage is a wonderful tool for disseminating the information obtained during the various phases of the project. Finally the webpage is linked to other chemistry department webpages and other useful websites. The webpage is still a work in progress, however, the chemistry webpage at Portland Community College is definitely facilitating chemistry education.

390. THE EMSL ELECTRONIC NOTEBOOK. James D. Myers*, Elena S. Mendoza, William T. Valdez, and Wyllona M. Harris, Pacific Northwest National Laboratory, MS K8-91, 3335 Q Ave., Richland, WA 99352.

As part of Pacific Northwest National Laboratory's Environmental and Molecular Sciences Collaboratory project and the Department of Energy's DOE2000 Electronic Notebook project, we have developed a WWW-based Electronic Laboratory Notebook (ELN). The ELN is a multi-media, sharable, and interactive version of the traditional paper laboratory notebook. It allows user to share data, sketches, molecular structures, equations, etc. and can easily be extended to support additional types of entries. The ELN also supports encryption and digital signatures, searching, automated entry from instruments, and other advanced capabilities. The Electronic Notebook is currently used by a variety of researchers and educators around the country, and is a standard service offered to users of the Environmental Molecular Sciences Laboratory (EMSL). In education it allows students to share their data and experiments and get feedback from their instructors and fellow students. Also, interns and student researchers are able to connect with their research sponsors in industry in separate locations. In this talk we will discuss the features of the Electronic Laboratory Notebook and present details of how several groups have used it to support their research and education projects.

391. A NOVICE LOOKS AT THE STATE OF ELECTRONIC PUBLISHING. John D. McCallum, DSquared Development, 905 M Ave., La Grande, OR 97850.

A former chemical educator and current technical writer looks at the transition from education to electronic publishing. Digital documentation of information is growing exponentially. There are some good reasons why it is taking off, but also some frightening side effects. This presentation will show anecdotal evidence of the advantages and disadvantages of publishing electronically. An overview of the current state of electronic publishing (via the internet and other electronic documents) will be given, looking at the software used to create electronic documents and the strengths and weaknesses of those documents. The working of search engines and their failure to work will also be explored. In conclusion, a few proposals on creating a more efficient future for electronic publishing will be discussed.

392. WEB-BASED REALIZATIONS OF THOUGHT EXPERIMENTS FOR TEACHING UNDERGRADUATE QUANTUM MECHANICS. Robert J. Hinde, Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600.

Many of the concepts typically presented in quantum mechanics courses are highly abstract and at odds with our everyday experiences in the macroscopic world. This makes it difficult for novice learners to appreciate that quantum mechanics provides the correct description of phenomena at the atomic and molecular level. Judicious use of "thought experiments" allows students to connect the abstract principles of quantum mechanics with real physical phenomena in the microscopic world. Using the World Wide Web, we can convert these "thought experiments" into real experiments in which students learn quantum mechanical principles through self-guided discovery and exploration. I will discuss some of the successes and failures of this approach based on my own experience teaching a fairly traditional second-semester physical chemistry course.

393. TEACHING INTRODUCTORY CHEMISTRY ON THE INTERNET. Walter V. Volland and Gloria M. Volland, Department of Chemistry, Bellevue Community College, 3000 Landerholm Circle SE, Bellevue, WA 98007.

Growth of the Internet has led to the development of an introductory chemistry course without a physical classroom. This course is part of an Associate of Arts degree offered entirely over the Internet in Washington State. Course content is the same as for a traditional introductory course. Web activities related to course topics, chat rooms, frequent exchange of e-mail between students and instructor, and virtual office hours are integral parts of the class. Since students do all their work off campus, safe, environmentally-friendly ("green") home experiments using consumer products were developed. These are similar to experiments done in a traditional laboratory setting. Sample material can be seen at the following URL: http://www.scidiv.bcc.ctc.edu/wv/101-online.html . Problems developing "green" labs, typical experiments, and pros and cons of the new mode of instruction will be discussed.

394. (withdrawn)

395. FOUNDING A SMALL CHEMICAL COMPANY: LESSONS AND LACERATIONS. Allen Erickson, Lacamas Laboratories, 3625 N. Suttle Road, Portland, OR 97217-7713.

This paper will discuss the first 15 years of Lacamas Laboratories, a small fine chemical manufacturer. The early years of Lacamas Laboratories will be emphasized, especially the people and events which helped the company succeed.

396. STARTING AND RUNNING AN ANALYTICAL LABORATORY. Susan M. Coffey, Coffey Laboratories, Inc., 12423 N.E. Whitaker Way, Portland, OR 97230.

Susan M. Coffey, President of Coffey Laboratories, Inc., will speak about starting and running a laboratory. She and her father started Coffey Labs 20 years ago, and she will give a brief history of the company. Some topics included in this talk will be factors involved in deciding to start your own business, problems to overcome, rewards that can be obtained, what it is like to work with family members, and how companies change with growth.

397. HISTORY OF THE SALISHAN WINERY. Joan Wolverton, 35011 North Fork Ave., La Center, WA 98629.

If a tiny vineyard/winery operation can survive a volcanic eruption, banana slug invasion, and 30 years of regulation by more than a dozen governmental agencies, you, too, can make it in the world of small business. Tips - and combat stories - from Joan Wolverton, winemaker, farmer, owner of and marketer for Salishan Vineyards in Clark County, Washington.

398. SYNTHETECH, INC.: A CHEMICAL COMPANY IN A CONSTANT STATE OF TRANSITION. Paul C. Ahrens, 3510 Glenridge Dr., Corvallis, OR 97330-3212.

Synthetech has grown through several transitions: Private company to public company, Colorado-based to Oregon-based, technology-driven to market-driven, milligram to kilogram to multi-ton manufacturer, losing money to making money. Starting from "two guys in a garage" in 1981, Synthetech has grown to become a world class supplier of amino acid derivatives to the pharmaceutical industry. A simple management philosophy was used: hire people smarter than you, treat them well and let them do their job.

399. LESSONS LEARNED IN BOOTSTRAPPING A CHEMISTRY-BASED BUSINESS. Daniel Brose, Chemica Technologies, Inc., 20332 Empire Ave., Suite F-3, Bend, OR 97701.

Chemica Technologies is a small company that develops products for pharmaceutical and medical use. In this very practical presentation, Dan Brose will answer questions such as: How does one go about starting a technology-based business from nothing? Is it worth the trouble to seek government grants (e.g., SBIR)? Should you seek investors and/or take on debt when you start your business? What are the most common mistakes made by chemists and engineers who start their own businesses? Where can you get competent business advice? What are the barriers to entry into the pharmaceutical and medical fields?

400. ACQUISITION: THE PLEASANT (?) FATE OF MANY SMALL CHEMICAL BUSINESSES. John Cochran, 1141 NW Summit Drive, Bend, OR 97701-5688.

The acquisition of a small chemical business can bring benefits and problems for the acquirer and the acquired. The manner in which both parties approach the acquisition and the expectations of both sides will determine if the experience will continue to be a pleasant one after the honeymoon is over. The author explores this subject from both sides of the table, having been a stockholder in two businesses that were acquired and now as a senior manager in a company that has made several acquisitions in recent years.

401. HISTORY OF CASCADE CHEMICALS. Andrew Lambrie, Cascade Chemicals Inc., 16081 SE Evelyn Street, Clackamas, OR 97015.

The discussion is broken down into some eight sub-sections which detail the factors one must take into consideration when involved in a small chemical manufacturing operation. It highlights the government, state, or county regulators who in effect control or oversee what you are allowed to do within your facility. Financial resources are also an important concern. The number of outlays faced on a monthly, quarterly, and annual basis are enumerated. Quality control, packaging, shipping, and handling concerns round out the talk.

402. VARIATIONAL TRANSITION STATE THEORY OF NUCLEATION: APPLICATION TO SMALL WATER CLUSTERS. Shawn M. Kathmann*, Gregory K. Schenter, and Bruce C. Garrett, Molecular Theory Group, Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999 MS:K1-96, Richland, WA 99352.

Vapor to liquid nucleation is a dynamical process governed by a delicate interplay between condensation and evaporation rates. Since the vapor is comprised essentially of monomers, the formation of clusters is governed by monomer association and dissociation reactions. The formation of a cluster is impeded by a free energy of activation which, since no potential energy barrier exists, is entropic in nature. Variational transition state theory provides a framework in which equilibrium evaporation rate constants can be calculated and the corresponding condensation rate constants determined from detailed balance. The nucleation rate can then be obtained by solving the pseudo-first order kinetic equations.

403. THE U. S. ENVIRONMENTAL PROTECTION AGENCY'S GREEN CHEMISTRY PROGRAM. Lauren B. Bartlett, Paul T. Anastas, and Tracy C. Williamson, Office of Pollution Prevention and Toxics (7406), U.S. Environmental Protection Agency, 401 M Street, S.W., Washington, DC 20460.

Numerous accomplishments in environmental protection and pollution prevention have been realized in recent years through the use of green chemistry. Green Chemistry, or "pollution prevention at the molecular level," is chemistry designed to reduce or eliminate the use or generation of hazardous materials associated with the manufacture and use of chemical products. This innovative new approach to pollution prevention is being widely adopted by academia, industry, and government in the United States. Activity in this area ranges from fundamental research of new chemical transformations and reaction conditions to incorporation of the concept into industrial processes. The U.S. Environmental Protection Agency has been very involved for several years in promoting this approach to pollution prevention through workshops, symposia, publications, and press coverage on the subject, and in March of 1995 President Clinton announced the Green Chemistry Challenge as a high priority project in the area of environmental protection. This poster will provide an overview of EPA's Green Chemistry Program, including the Green Chemistry Challenge.

404. GREEN CHEMISTRY: A NEW APPROACH TO POLLUTION PREVENTION. Lauren B. Bartlett, Paul T. Anastas, and Tracy C. Williamson, Office of Pollution Prevention and Toxics (7406), U.S. Environmental Protection Agency, 401 M Street, S.W., Washington, DC 20460.

Numerous breakthroughs in environmental protection and pollution prevention have been realized in recent years by both industry and academia through the use of green chemistry. Green Chemistry, or "pollution prevention at the molecular level," is chemistry designed to reduce or eliminate the use or generation of hazardous materials associated with the manufacture and use of chemical products. Example of green chemistry approaches to environmental protection and pollution prevention include the use of alternative feedstocks, the use of alternative solvents and reaction conditions, and the design of safer chemicals. Through the design and implementation of one or more of these green chemistry approaches, chemists have found ways to remove millions of pounds of hazardous substances from the products and processes that society needs, without sacrificing scientific innovation and creativity. In addition, the implementation of green chemical methodologies has been shown, in many cases, to provide economic benefits as well. This poster will provide an overview through example of the various areas of Green Chemistry that are being researched, developed, and implemented in academia and industry and will highlight the resulting economic, human health, and environmental benefits.

405. DIRECT DYNAMICS STUDY OF THE REACTION PATH AND RATE CONSTANTS OF OH- + CH3Cl ¦ CH3OH + Cl- . Edgar E. Arcia, Yurii A. Borisov, Steven Mielke, and Bruce C. Garrett, William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352 and Nesmeynov Institute of Organo-Element Compounds, Russian Academy of Sciences, Moscow, Russia.

The title reaction was studied by ab initio molecular orbital theory. The geometries for the reactants, products and transition state were optimized at the MP2/aug-cc-pvdz level of theory, and the minimum energy path was followed by the local quadratic approximation of Page-McIver. In order to improve the energetics along the minimum energy path, an extrapolation to the complete basis set limit at the CCSD(T) level was performed. The forward rate constant for the temperature range 300-1200 K was obtained by variational transition state theory. The effects of solvation on the energetics and the rate constant were investigated by the inclusion of two water molecules in the system.

406. THE ROLE OF INDUCING MOLECULES IN REPAIR AND REGENERATION. Doros Platika, Ontogeny, Inc., 45 Moulton Street, Cambridge, MA 02138.

Developmental biology is the study of how cells, tissues and organs change as they interact during development. Ontogeny's research is based on the process whereby an organism changes its size, shape and organization from a fertilized egg to a mature individual. The same processes and molecules that are active during development are reactivated in adult regenerative processes. Ontogeny is identifying ways to rejuvenate damaged systems by looking at the signaling processes of cells during development and restoring them in adults to trigger repair and regeneration. Ontogeny, with its corporate partners, has the following areas of focus:
- neurological disorders: Alzheimer's and Parkinson's disease, peripheral neuropathies
- orthopedic disorders: osteoarthritis, osteoporosis and bone and cartilage injuries
- dermatological disorders: skin cancer, wound healing and hair growth
- diabetes: cell therapy for juvenile onset diabetes; factors/small molecules for insulin-dependent diabetes in adults
- blood disorders.

407. TOTAL SYNTHESIS OF IBOGAMINE. James D. White* and Younggi Choi, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

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408. MOLYBDENUM MEDIATED ALLYLATION AND CROTYLATION. M. Sundaram Shanmugham, Kevin P. Gable, and James D. White*, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

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409. SYNTHESIS OF TWO SUBUNITS OF THE HEPATOTOXIC ALKALOID CYLINDROSPERMOPSIN. James D. White* and Joshua D. Hansen, Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003.

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410. SYNTHESIS OF 2-DEOXY-2-PHOSPHONOMETHYL-D-ARABINOSE AS A POSSIBLE KDO SYNTHETASE INHIBITOR. Todd R. Boehlow and Cynthia K. McClure*, Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717.

Gram-Negative bacteria metabolize D-arabinose to produce 3-deoxy-D-manno-2-octulosonic acid (KDO) which is used in the production of lipopolysaccharides (LPS) for the bacteria cell wall. The 2-hydroxy group of D-arabinose eventually becomes the 5-hydroxy group of KDO and it is this hydroxy group that is involved in the 1,5-glycocidic linkage in the LPS production. By substituting the 2-hydroxy group of D-arabinose with a phosphonomethyl group, it is theorized that this metabolic pathway can be shut down. Reaction of P(V) 1 with the acetyl protected glyceraldehyde yields the protected straight chain phosphonomethyl D-arabinose 2. Conversion of the acyl silane to the corresponding aldehyde followed by deprotection of the diol yields the desired D-arabinose derivative 3.
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411. SYNTHETIC STUDIES TOWARD THE PREPARATION OF PHOSPHONATE ANALOGS OF SPHINGOMYELIN AND CERAMIDE 1-PHOSPHATE USING PENTACOVALENT ORGANOPHOSPHORUS METHODOLOGY. Cynthia K. McClure* and Pranab K. Mishra, Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717.

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412. STEREOSELECTIVE SYNTHESIS OF EPOTHILONE B. James D. White*, Rich G. Carter, and Kurt F. Sundermann, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

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413. A SYNTHETIC APPROACH TO THE NOOTROPIC AGENT HUPERAZINE A. Jungchul Kim and James D. White*, Department of Chemistry, Oregon State University, Corvallis, OR 97331.

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414. SOLID-PHASE SYNTHESIS OF SEMI-SYNTHETIC DERIVATIVES OF BACITRACIN A. Patrick G. McDougal*, Meredith. R. Miller, Allison A. Henry, Takashi Nakai, , Department of Chemistry, Reed College, Portland, OR 97202 and John H. Griffin, Department of Chemistry, Stanford University, Stanford, CA 94305.

In an effort to study the mechanism of action of the antibiotic, bacitracin A (1), a series of semisynthetic derivatives of bacitracin A (2-4) have been prepared via solid-phase synthesis. Specifically, the thiazoline tail of bacitracin A has been modified in order to explore the connection between metal chelation and antibiotic activity. The synthetic strategy follows that reported for the synthesis of bacitracin A (Lee and Griffin, J. Org. Chem. 1996, 61, 3983).
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