New tetra:fluoro-phenyl ester cpds. for use in liquid crystal medium - for electro=optical display esp. having high dielectric anisotropy

摘要

New tetrafluorophenyl esters (I) are of the formula: n = 0-7; Q = -O-, -CH=CH- or a single bond; r = 0, 1, 2, 3, 4, or 5; s = 0, 1 o3 2; Z = a single bond, -(CH2)2- or -(CH2)4-; A = single bond, trans-1,4-cyclohexylene, unsubstd. or F-substd. 1,4-phenylene or biphenyl-4,4'-diyl. (I) can be prepd. (not claimed) by standard methods, e.g. as described in Houben-Weyl, Methoden der Organiscen Chemie, Georg-Thieme-Verlag, Stuttgart. USE/ADVANTAGE - (I) are claimed for use in liqid crystal (LC) media for electrooptical displays, esp. LCDs. They are esp. useful in STN cells, with very steep electrooptical characteristics and in active matrix displays with excellent long term stability. (I) have higher dielectric anisotropy and perpendicular dielectric constant than the pentafluorophenyl esters.