May 28, 2008
by Arvin Moser, Team Manager, Application Scientists, ACD/Labs
Although peak crowding can be a nuisance, a monosubstituted benzene fragment can be identified by a 1H NMR. A good marker for a monosubstituted benzene ring, and thus how an elucidator can clue in to its presence for an unknown, is whether the sum of the relative integrals for the aromatic resonances add up to 5.
Below are 6 1H NMR spectra illustrating the various patterns for a monosubstituted benzene fragment. Although other possibilities can exist, these are the typical patterns to be on the lookout for in the aromatic region.