Properties of the Liquid Crystals Formed by Certain 4′-n-Alkoxyphenyl Biphenyl -4- Carboxylates

Twelve 4′-n-alkoxyphenyl biphenyl-4-carboxylates have been prepared and their liquid crystal transition temperatures determined. Members of the homologous series were studied by differential thermal analysis and the enthalpies of fusion of the various transitions were measured. In contrast with the isomeric homologous series, the 4-biphenylyl 4′-n-alkoxybenzoates (previously reported), the 4′-n-alkoxyphenyl biphenyl-4-carboxylates do not have smectic mesophases and, in general, have lower liquid crystal transition temperatures and enthalpies of fusion. An explanation for this behaviour is offered.