Syntheses and mesomorphic properties of laterally fluorinatedphenyl isothiocyanatotolanes and their high birefringent mixtures

Syntheses and mesomorphic properties of di-, tri- and tetrafluorosubstituted 4'-(4-alkylphenyl)-4-isothiocyanatotolanes are described. Four fluorine substituted compounds in the position 2', 3', 3, and 5 show stronger nematic character than difluorosubstituted ones in the position 3, 5 or 2', 3'. Example of high birefringence nematic mixture and its properties are given.