Synthesis and Properties of Novel Liquid Crystalline Compounds having a Difluoromethyleneoxy Moiety as a Linkage Group

Novel liquid crystal compounds having a difluoromethyleneoxy group as a linkage group have been prepared by the new synthetic method using dibromodifluoromethane in good yield. From the results of physical property measurements; i.e., transition temperature, dielectric anisotropy (Δ˜), birefringence (Δn) and viscosity, it becomes obvious that the derivatives having 3,5-Difluorophenyl group at the carbon side of difluoromethyleneoxy group (1) have high dielectric anisotropy and low viscosity, and the derivatives having 1,4-cyclohexylene group at the carbon side of difluoromethyleneoxy group (2) have good balance of their physical properties. Moreover, 1 and 2 indicate high voltage holding ratio. Therefore, a novel series of the compounds having a difluoromethyleneoxy linkage group is an eminently suitable material that can lower driving voltage and achieve quicker response time of the AM-LCDs.