Synthesis and mesomorphic behaviour of high polarisability materials for non-linear optical applications

A variety of high polarisability materials have been synthesised with thioester and alkyne linking groups, and isothiocyanato and cyano terminal groups. The synthesis of these materials is presented and the transition temperatures and optical parameters of the materials are discussed and compared to those of the parent ester and non-linked analogues. The thioester and isothiocyanate units provide very high polarisabilities although the isothiocyanato unit leads to reduced mesophase thermal stabilities when compared to analogous cyano-terminated mesogens.