A nuclear magnetic resonance study of aromatic substituent effects in 1-X-2,4-dimethylbenzenes

Abstract

The ¹H n.m.r. spectra of a number of 1-substituted 2,4-dimethylbenzenes have been studied. Correlations between the parameter Q(originally defined by Hruska, Hutton, and Schaefer, Canad. J. Chem., 1965, 43, 2395) and the chemical shifts of both the proton adjacent to the substituent and the protons of the adjacent methyl group were observed. The chemical shifts of protons meta to the substituent were also shown to exhibit a correlation with the Hammett σ(meta) constants, although of the two correlations this is the less good.