Bent-shaped achiral azo compounds exhibiting banana mesophases

Two novel series of bent-shaped achiral azo compounds with the following molecular structures have been synthesised and characterised. [GRAPHICS] The object of the present work was to study the effect of molecular structure on the mesomorphic properties of bent-shaped molecules. The compounds of series 1 exhibit different types of banana mesophases. These compounds with unsymmetrical molecules exhibit mainly B-1 phase, in addition to other higher ordered smectic mesophases (X-2 and X-3, the optical textures of which are reminiscent of banana phases). The compounds of series 2, with symmetrical molecules exhibit only one type of mesophase i.e.. B-7 when (-X=Y-) = (-N=CH-) and X4 (unidentified mesophase with textural features of a banana phase) when (-X=Y-) = (-CH=N-). From the studies carried out here, it has been found that. even minor modifications such as, the reversal of linkage groups in the molecules can lead to a considerable change in the mesomorphic properties.