A Facile Synthesis of Novel Liquid Crystalline Materials Having a Trifluoromethoxy Group and Their Electro-Optical Properties
作者:Kiyoshi Kanie、Sadao Takehara、Tamejiro Hiyama
DOI:10.1246/bcsj.73.1875
日期:2000.8
Novel liquid crystals (LCs) containing a trifluoromethoxy group connected to a cyclohexane mesogen or to an alkyl tail were prepared through an oxidative desulfurization-fluorination reaction of the corresponding dithiocarbonates. They were compared with LCs containing a methoxy group with respect to phase transition behavior and physical and electro-optical properties. Most of the CF3O-substituted LCs exhibited in a wide range of temperatures LC phases depending on the type of a mesogenic structure. LCs with a trifluoromethoxycyclohexane mesogen were shown to be thermally more stable than the LCs with a trifluoromethoxybenzene mesogen. LCs having a trifluoromethoxyalkyl tail show physical and electro-optical properties favorable to materials for not only TN-LCDs but TFT-addressed TN-LCDs. Furthermore, 3-β-CF3O-substituted cholestane was shown to be a potential chiral dopant for TFT-addressed TN-LCDs.
通过对相应的二硫代碳酸酯进行氧化脱硫-氟化反应,制备了含有与环己烷介质或烷基尾部相连的三氟甲氧基的新型液晶。在相变行为、物理和电光特性方面,它们与含有甲氧基的低聚物进行了比较。大多数 CF3O 取代的低聚物在不同的温度范围内表现出低聚物相,这取决于介源结构的类型。结果表明,具有三氟甲氧基环己烷中间体的低聚物比具有三氟甲氧基苯中间体的低聚物具有更高的热稳定性。具有三氟甲氧基烷基尾部的低聚物不仅显示出有利于 TN-LCD 材料的物理和电光特性,还显示出有利于 TFT-addressed TN-LCD 材料的物理和电光特性。此外,3-β-CF3O 取代的胆甾烷被证明是一种潜在的手性掺杂剂,可用于 TFT-addressed TN-LCD。