Anisole, acetophenone and benzoic acid methyl ester oriented in a nematic phase: Structure and internal motion

Abstract 1H‐, 1H{2D}‐, 2D‐ and 2D{1H}‐N.m.r.‐spectra were used in an investigation of the partially oriented molecules anisole, acetophenone and benzoic acid methyl ester. The phenyl ring geometries were found to deviate slightly from the regular hexagon. For anisole and acetophenone the measured couplings indicate a structure with the substituent group in the plane of the ring and one of the methyl protons pointing away from it. It is not possible, however, to draw further conclusions on the depths and shapes of the potentials hindering the internal motions. For benzoic acid methyl ester the measurements indicate that the dominant conformer is the one with the OCH3 axis approximately parallel to the effective molecular C2‐symmetry axis. Semiempirical MO calculations were found to provide reasonable molecular structures but no information on the potentials.