Organic Chemistry II

Professor Carl C. Wamser

Chem 335 - Winter 2007

Chapter 13 Skills

Spectroscopy - Structure Determination

Knowledge - Level 1

Terminology:

electromagnetic radiation, frequency, wavelength, wavenumber
spectroscopy, absorption spectrum
index of hydrogen deficiency (degrees of unsaturation)

nuclear spin, precession, resonance
shielding/deshielding effects, chemical shift, TMS, ppm (delta)
spin-spin splitting, coupling constant, (n+1) rule
C-13 NMR, MRI

vibrational modes, fingerprint region, stretching frequencies
electronic energy, lambda max

m/z , mass-to-charge ratio
parent molecular ion - reference for M , M+1 , M+2 , M-1 peaks
base peak
low-resolution, high-resolution mass spectrometry


Concepts - Level 2

identify characteristics of electromagnetic radiation

identify types of molecular energy levels and the types of radiation that stimulate transitions within those energy levels

explain the concept of nuclear spin, the effects of a magnetic field, and the phenomenon of resonance

describe the types of vibrational energy modes - e.g., stretching, bending

explain the basic workings of an IR, UV-visible, NMR, or Mass Spec instrument

recognize possible ionization and fragmentations of a molecule


Applications - Level 3

predict the number of peaks, their integrated area ratios, their approximate chemical shifts, and their spin-spin coupling patterns for a given compound in both H and C NMR spectra

use IR tables to identify the presence or absence of various functional groups

predict whether a compound will show absorption in uv/visible and an approximate lambda max

deduce the presence or absence of Br, Cl, S, N in a mass spectrum

identify the base peak and parent molecular ion in a typical mass spectrum

identify structures of major fragments in a mass spectrum


Analytical Skills - Level 4 & higher

identify the likely structure of a compound based on spectral and other data