Teaching Chemical Information:
Tips and Techniques

— June 1997 —

Steps to Follow to Identify Compounds from Spectra

Locate a spectrum of a known compound.
Use the sources listed in the “Major Sources for Spectra”, e.g., Aldrich, Sadtler, Hershenson, etc.
Identify a compound from its spectrum.
1. Make preliminary assignments of the compound’s structure based on information learned in class.
  NMR: look for presence/absence of aromatic ring (8 6.7-9); methyl (usually near 8 1); alkene H (usually 8 5-7), etc.
  
  IR: certain peaks are characteristic of specific structure, e.g., frequency of carbonyl stretch, presence/absence if OH or NH, of triple bonds, etc.
2. Extend and confirm your preliminary assignments and assign other diagnostic peaks by consulting your lab text and Silverstein/Bassler Morrill, Spectrometric Identification of Organic Compounds). (on reserve) and Pavia, Introduction to Organic Laboratory Techniques (on reserve).
3. Decide on list of possible structures (may be partial structures or model structures):
  Look in sources listed in the “Major Sources for Spectra” guide for the spectra of possible compounds/structures.
4. Identify correct compound from check of spectra sources.