Effects of a Polar Lateral Nitro Group on the Appearance of Mesophases of 4,4′-Bis(benzoyloxy)biphenyls

Abstract

Four types of 4,4′-bis(benzoyloxy)biphenyls were synthesized to investigate the effects of the lateral polar nitro group on appearance of mesophases as well as improvement of the mesomorphic property. In the case of 4,4′-bis(4-alkoxybenzoyloxy)biphenyls and 4,4′-bis(3,4- and 2,4-dialkoxybenzoyloxy)biphenyls, their transition temperatures were reduced by the introduction of the polar lateral nitro group because of the increasement of the molecular breadth. The nitro group in 4,4′-bis(3,4,5-trialkoxybenzoyloxy)biphenyls enhanced the transition temperatures and mesomorphic properties since the trialkoxy derivatives without a nitro group were not mesomorphic and those with a nitro group had a hexagonal columnar phase. The introduction of the nitro group did not increase the molecular breadth of the trialkoxy derivatives because they already have the wide molecular breadth.