A dipole moment study of the ortho-effect in di- and tri-substituted NN-dimethylanilines

Abstract

Apparent dipole moments in benzene of 2-methyl-, 2,3-, 2,4-, 2,5-, 2,6-, and 3,5-dimethyl-, 4-bromo-2,6-dimethyl, 2,6-dimethyl-4-nitro-, 2,4,6-timethyl-, and 2,4,6-tribromo-NN-dimethylaniline have been determined. Values for the magnitude and direction of the NN-dimethylaniline moment necessary to explain the dipole moments of six of these compounds are discussed in terms of the rotation of the dimethylamino-group from its position of maximum conjugation with the ring and the consequent change in vector moment in the direction of the major axis of the ring. The effect of p-substitution in restoring some conjugation between the dimethylamino-group and the ring is also noted.