Internal rotation in dimethylaniline and para-substituted derivatives

Abstract

A study of internal rotation in para-substituted dimethylanilines by ¹H n.m.r. spectroscopy shows that the barrier to internal rotation of the dimethylamino-group is markedly dependent upon the nature of the para-substituent, and a Hammett correlation gives ΔG^‡(at 133°K)= 5·1 (±1·0) kcal mol^–1 for rotation in the parent compound dimethylaniline itself.