NMR-STUDY OF THE CONFORMATIONS ADOPTED BY 1,2,3-TRIMETHOXYBENZENE WHEN DISSOLVED IN A NEMATIC LIQUID-CRYSTALLINE SOLVENT

The proton, proton-{deuterium} and deuterium NMR spectra of partially deuteriated samples of 1,2,3-trimethoxybenzene dissolved in a nematic liquid crystalline solvent, 132, have been recorded and analysed to yield a set of dipolar couplings which have been used to test models for the conformational distribution. It is shown that the molecule must exist in more than one conformation. A conformational distribution has been obtained which is in agreement with the data, and which is based on the assumption that each methoxy group can occupy positions either orthogonal to, or coplanar with, the phenyl ring plane.