Synthesis and mesomorphic properties of tolane-based liquid crystals with a fluorinated polar end group

Three series of tolane-based liquid crystalline compounds with a fluorinated polar end group have been synthesized. Their phase transition temperatures were measured by texture observation in a polarizing microscope and confirmed by DSC. The all-fluorinated trifluoromethyl and trifluoromethoxy group have a tendency to promote the smectic A phase, but the difluoromethoxy group has the tendency to promote a wide nematic phase.