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Solvent effects on the structures of benzene and chlorobenzene were studied by NMR of partially oriented molecules in six liquid crystals. Allowing for the correlation between vibration and rotation, a unique solventindependent r. structure could be determined for both molecules. The contributions of equivalent bonds to the orientation energy of the two molecules were found to differ slightly.KEY WORDS NMR r, structure of benzene and chlorobenzene orientation

The chemical shifts and the direct and indirect spin-spin coupling constants of HCN have been measured in various liquid crystal solvents. The sign of the indirect coupling constant J(15NH) is fonnd to be negative. The C shift anisotropy is 334 f 20 ppm. The molecular structure apparently varies considerably with the solvent used. These solvent effects, which can be attributed to a correlation between vibration and rotation of the molecule, are corrected.

The r, structures of ethylene and 1,l-difluoroethylene have been determined by NMR of partially oriented molecules, considering the interaction between the solute molecule and the liquid crystal solvent which leads to a correlation between molecular vibration and rotation. The analysis of the data also provides the interaction parameters which characterize the torques acting on the individual molecular bonds, deforming and simultaneously orienting the solute. A linear relationship between the interaction parameters for the C-H bonds of the two solutes and methane in the same solvents has been found.

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