AN NMR-STUDY OF THE CONFORMATIONAL FLEXIBILITY OF PHENYL ACETATE DISSOLVED IN A NEMATIC LIQUID-CRYSTALLINE SOLVENT

The H-1, H-2 and C-13 NMR spectra of phenyl acetate, phenyl acetate-[( CO)-C-13] and phenyl acetate-[(CH3)-H-2] dissolved in a nematic liquid crystalline solvent have been analysed to yield dipolar coupling, D-i j. These have been interpreted using the additive potential model to p rovide information on the molecular conformation, resulting in three p ossible shapes for V(phi), the potential energy for rotation about the ring-oxygen bond. A comparison with the results of molecular orbital calculations leads to the conclusion that a potential with a minimum a t 54.4 degrees +/- 0.1 degrees is the most probable.