A study of the molecular structure and of the barrier to methyl rotation ino-chlorotoluene partially oriented in the nematic phase

Abstract

The N.M.R. spectrum of o-chlorotoluene, dissolved in the nematic phase of 4-methoxybenzylidene-4-amino-α-methylcinnamic acid n-propylester is analysed and the shape of the proton skeleton determined. The position of lowest energy of the potential barrier to methyl rotation is found to be that in which the chlorine atom is staggered to the methyl group, and the height of the barrier is of the order of 5·0 kJ mol^-1 (1200 cal/mole).