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 dibromo-difluoromethane in good yield. From. the results of physical property measurements; i.e., transition temperature, dielectric anisotropy (Deltaepsilon), birefringence (Deltan) and viscosity, it becomes obvious that the derivatives having 3,5-Difluorophenyl group at the carbon side of difluoramethyleneoxy group ((1) under bar) have high dielectric anisotropy and low viscosity, and the derivatives having 1, 4-cyclohexylene group at the carbon side of difluoromethyleneoxy group ((2) under bar) have good balance of their physical properties. Moreover, (1) under bar and (2) under bar 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.