Diacetylenic Liquid Crystalline Diesters

Abstract

Abstract Diesters of 10,12-doosadiyne-1, 22-dioic acid with 4-hydroxy-4′methoxybiphenyl (I), 4-hydroxy-4′-methoxyazoxybenzene (II), and 4-hydroxy-4′-methoxy(2,2′-dimethyl) azoxybenzene have been prepared. The diester I displayed high sensitivity to light and U.V. irradiation while it was not mesomorphic. In contrast, diesters II and III were nematic while displaying considerably less radiation sensitivity. A suggested reason for this difference in behavior is the difference in the molecular packing of the corresponding crystal. The difference in the mesomorphic behavior between II and III is explained in terms of mesogen broadening and distortion of the mesogen molecule of III by the methyl substituents.