Mesomorphic Properties of Some Phenyl Benzoate Dericatives

The effect of terminal alkyl and alkoxy substituents on the mesomorphic properties of p-alkylphenyl p-alkylbenzoates, p-alkylphenyl p-alkoxybenzoates, p-alkoxyphenyl p-alkylbenzoates, and p-alkoxyphenyl p-alkoxybenzoates was studied. It was found that, with relatively few experiments, one could make reasonable predictions as to the mesomorphic thermal properties of a particular series of compounds. Although, as is well known, reliable predictions of the crystal-to-mesophase transition temperature based on molecular structure cannot be made, predictions of the mesophase-to-isotropic transition temperature can be made once several members of a series have been prepared. The ability of terminal alkyl and alkoxy substituents to promote liquid crystallinity in the phenyl benzoate system was evaluated. The ester central linkage was also compared with other central linkages in regard to mesomorphic potential.