Synthesis and mesomorphic properties of a triphenylene-based discotic liquid crystal molecule with bisazobenzene at the periphery

Abstract

A new triphenylene liquid crystal material with six rod-shape bisazobenzene moieties as the peripheral units has been synthesized and characterized by spectroscopic methods. The mesomorphic properties were investigated by differential scanning calorimetry, polarizing optical microscopy and, X-ray diffraction. The mesogenic bisazobenzene was prepared by diazotization and coupling and subsequent etherification. The disc-shaped molecule, 2,3,6,7,10,11-hexakis[4`-(4-phenyazo)azobenzenehexyloxy]triphenylene was prepared by etherification of 1-bromohexyloxy-4`-(4-phenylazo)azobenzene on to the 2,3,6,7,10,11-hexahydroxytriphenylene nucleus. The presence of a nematic and smectic A mesophases was confirmed by optical textures and X-ray diffraction measurement.

Keywords: Liquid crystal, Bisazobenzene, Triphenylene, Nematic phase, Semectic phase,