New liq. crystal cpds. with terminal chloro or mono-, di- or tri-fluoro gp. - having low viscosity, relatively high dielectric ansiotropy and nematogenity, good performance at low tenmps. and good suppression of smectic phases

摘要

Liq. crystal cpds. of formula (I) are claimed: R = H, 1-15C alkyl(enyl) opt. substd. with CN or CF3 or one or more halogen, with one or more non-adjacent CH2 gps. opt. substd. by O, S cyclobutandiyl, -CO-, -CO-O-, -O-CO- or -O-CO-O-; Z,Z' = -CH2CH2-, -CH=CH-, -CC-, or a single bond, and one of Z,Z' may also be -(CH2)4- or -CH=CH-CH2CH2-; A,A' = trans-1,4-cyclohexylenyl with 1-2 non-adjacent CH2 gps. opt. substd. by O, or opt. mono- or di F and/or Cl substd. 1,4-phenylene with 1-2 CH gps. opt. substd. by N; m = 0-3; (O+S) = 0-2, with (S+O) greater than or equal to 2; W = O, -COO- or a single bond; Q = O, -CH=CH- or a single bond; r = 1-7; t = 0-7; and y = F, Cl, CF3, OCF3 CHF2, OCHF2 or OCH2F. USE/ADVANTAGE - Liq. crystal and electro-optic indicators contg. liq. crystal media contg. at least two liq. crystal components and at least one cpd. of formula (I) or (II) are claimed. (I) are partic. useful for displays based on the drilled cell, guest-host effect, deformation of phases or dynamic scattering effect principle. The claimed cpds. have comparatively low viscosities, relatively high dielectic anisotropies and nematogenities, good performance at low temps. and the smectic phases are effectively suppressed.