PRINCIPAL VALUES OF C-13 NMR CHEMICAL-SHIFT TENSORS FOR A COLLECTION OF SUBSTITUTED BENZENES

Principal values of 63 NMR chemical shift tensors were determined for atomic carbon atoms in 12 di-, tri-, and tetrasubstituted benzenes. The values were calculated from CP/MAS carbon-13 NMR spectra with the Herzfeld-Berger method. An empirical chemical shift additivity relationship was established for substitution by hydroxyl, methoxyl, aldehyde, carboxylic acid, and substituted alkyl functional groups. This relationship was successful in predicting principal values, usually within ±5 ppm. © 1990, American Chemical Society. All rights reserved.