Design and Synthesis of Novel Calamitic and Discotic Materials Based on the Photorefractive Carbazole Unit

The incorporation of photorefractive molecular units, such as carbazole, into anisotropic materials (liquid crystals) may offer many advantages over conventional electrical poling of photorefractive polymers. Thus, a series of symmetric 3,6-disubstituted carbazole derivatives with well-known biphenyl and triphenylene liquid-crystalline moieties was synthesized and characterized. These modifications were achieved by the esterification of bishydroxy carbazole derivatives with monoalkylated biphenyl carboxylic acids and alkylation of bisacylated bromo- derivatives of carbazole with monohydroxy pentaalkoxy triphenylene. The pure compounds are not liquid-crystalline, even when doped with trinitrofluorenone (TNF), unlike triphenylene/carbazole materials that we reported previously. These compounds, although not liquid-crystalline, may be of interest in the field of photorefractivity.