Synthesis and mesomorphic properties of fluoro and isothiocyanato biphenyl tolane liquid crystals

Four series of high birefringence biphenyl tolane liquid crystals having a terminal isothiocyanato or fluoro group were synthesized; their mesomorphic properties were studied by optical polarizing microscopy and DSC. These biphenyl tolane compounds exhibit reasonably low melting points and high birefringence of 0.37-0.49. By using these compounds a eutectic mixture was formulated exhibiting a wide nematic range, high figure-of-merit and low viscosity.