Columnar mesomorphism in heptazine discotics

Abstract

In this study, we report the design and synthesis of C3- symmetry columnar liquid crystals in which heptazine core is flanked with six alkoxy chains. These novel derivatives show hexagonal and rectangular columnar liquid-crystalline (LC) phases over a wide range of temperatures. All the compounds exhibit columnar hexagonal phase (Colh) at high temperatures, among which two compounds with lower alkoxy chains show a rectangular phase at lower temperatures. The mesomorphic properties of all the compounds are confirmed by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffractometry.