Liquid Crystalline Esters of Dibenzophenazines

A series of esters of 2,3,6,7-tetrakis(hexyloxy)dibenzo[ a, c]phenazine-11-carboxylic acid was prepared in order to probe the effects of the ester groups on the liquid crystalline behavior. These compounds exhibit columnar hexagonal phases over broad temperature ranges. Variations in chain length, branching, terminal groups, and the presence of cyclic groups were found to modify transition temperatures without substantially destabilizing the mesophase range.