Development of New Fluorine-containing Ferroelectric Liquid Crystals

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The purposes of this project are to develop a new and efficient synthetic method for optically active organofluorine compounds and, by using these as chiral building blocks, to develop new types of ferroelectric liquid crystals.First, the Tokyo Inst.Tech.group has developed the new, silyl triflate-mediated procedure for the Claisen rearrangement and successfully applied this Claisen procedure to asymmetric synthesis of alpha-fluoro-alpha-methyl and alpha-fluoro-alpha-trifluoromethyl carboxylic acid derivatives. Of particular interest is that the senses of asymmetric transmission observed with the fluorinated substrates are opposite to those observed with the non-fluorinated counterparts. Second, the Japan Energy Co.group has prepared a variety of liquid crystals by using the optically active fluorine compounds as the chiral building blocks and evaluated their functional properties as ferroelectric LC's. Notable findings are : (I) the fluorinated liquid crystals provide a larger degree of the spontaneous polarization than the non-fluorinated counterparts in general, (2) Liquid crystal with the alpha-fluoro-alpha-methyl chiral center show a greater spontaneous polarization than the liquid crystals with alpha-fluoro-alpha-CF_3 chiral center, and (3) The liquid crystal with a pyrimidine ring in the core part and alpha-fluoro-alpha-methyl ester moiety in the chiral part is shown to provide a greater than 400 nC/cm^2 of spontaneous polarization.