Mesomorphic Properties of Some Homologues of a Triphenylene Discotic Liquid Crystal Possessing Terminal Carboxylic Acids

Abstract

Asymmetrical triphenylene derivatives containing ester or carboxylic acids as terminal substituents were synthesized and characterized by DSC, optical microscopy and X-ray diffraction. It was found that all the ester homologues are non-mesomorphic, while most of the carboxylic acid homologues show a hexagonal columnar (Col_h) mesophase. Temperature dependent infirared spectra (of the carboxylic acid derivatives indicate the existence of strong hydrogen bonding interaction in the isotropic. mesomorphic and solid phases.