Conformational Studies on Mesogenic Monomers and Dimers

Abstract

The conformational properties of the isolated alkyl substituted cyano-biphenyls, cyano-phenyl-cyclohexanes and cyano-phenyl 1-1, 3-dioxanes are studied by molecular mechanics and by a point charge model. Especially the relative orientation of the rings and the flexibility of the alkyl groups are investigated. Structures with kinks in the alkyl chains and the length-broad relation (L/B) of the energetically preferred conformers are calculated. In the disubstituted cyclohexanes and 1, 3-dioxanes the e, e conformers are more stable than the a, a ones. Moreover, the molecular mechanics calculations are extended to the dimers of benzene, biphenyl, cyano-biphenyl and 4-n-hexyl-4′-cyano-biphenyl in order to investigate the preferred structures.