Question

This is the H-NMR spectrum for benzophenone. What can you tell me about the compound from looking at it? I need to mark up the spectra with notes.

7.9 7.8 7.7 7.6 Ppm 10 9 8 7 3 2 ppm 12 11

Answer 1

The molecule is symmetrical, both aromatic rings have equivalent hydrogens. 1. Two hydrogens of each ring have only one neighboring hydrogen so the signal that should appear corresponding to these hydros would be a doublet. 2. Three hydrogens of each ring have two neighboring hydrogen so the signal that should appear corresponding to these hydrogens would be a triplet. doublet signa wo triplet signals 7.9 7.8 7.7 7.6 Ppm 3. Two triplet signals are observed in the spectrum, this is due to the fact that the three hydrogen signals that give triplets (see point 2) are not equivalent, the hydrogen in the middle gives a different signal to the end signals. 2 10 9 8 3 2 ppm 12 11 Integration 2 corresponds to the two hydrogens that give doublet signal. Integration 3 corresponds to the three hydrogens that give triplet signal.