Synthesis of Three Ring Type Compounds with Fluorine and NCS Groups as Candidates for VA mode Liquid Crystal Display

  • Heo, E.Y. (Liquid Crystal Research Center, Department of Chemistry, College of Natural Sciences, Konkuk University) ;
  • Kim, Y.B. (Liquid Crystal Research Center, Department of Chemistry, College of Natural Sciences, Konkuk University) ;
  • Kim, S.H. (Liquid Crystal Research Center, Department of Chemistry, College of Natural Sciences, Konkuk University)
  • Published : 2003.07.09

Abstract

Three ring type liquid crystalline compounds having 4-alklycyclohexyl group, 1,2-difluorobenzene and phenylisothiocyanate moieties as main skeleton were designed to have negative dielectricity. However, the compounds with 2,3,2'-trifluoro-3'-isothiocyanated biphenylcyclohexane core did not exhibit the nematic liquid crystalline phase because of two conformers by interaction of isothiocyanate and adjacent fluorine atoms. Also, 4-alkyl-2,2',3'-trifluoro-3-isothiocyanated biphenylcyclohexane core was designed expecting to have uniform conformers of isothiocyanate group. In the course of developing polyimides for VA mode LCD, we synthesized alkyl-3,5-diaminobenzene efficiently with various length of alkyl chains from commercially available di-t-butyl malonate and 3,5-dinitrobenzoyl chloride as starting material.

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