Partly-fluorinated 1,2-di:substd. ethylene(s) - useful as components of liq. crystal media for electro-optical displays

摘要

Partly-fluorinated cpds. of formula R1-A1-(Z1-A2)m-Q-(A3-Z2)n-A4-R2 (I) are claimed; A1-A4 = (a) trans-1, 4-cyclohexylene (cyc) (opt. with non-adjacent CH2 gp(s). replaced by O and/or S and opt. substd. by CN or Hal), (b) 1, 4-phenylene (Phe) (opt. with 1 or 2 CH replaced by N and opt. substd. with CN or Hal), or (c) 1, 3-cyclobutylene, 1, 3-bicyclo(1.1.1)pentylene, 1,4-cyclohexyenylene, 1,4-bicyclo(2.2.2)octylene, piperidine-1, 4-diyl or naphthalene-2, 6-diyl (or corresp. decahydro or 1, 2, 3, 4-tetrahydro derivs.); R1, R2 = 1-15C alkyl, alkenyl or perfluoroalkyl (opt. substd. with CN, Hal or CF3 gp(s)., and opt. with 1 or more CH2 replaced by -S-, -O-, 1, 3-cyclobutylene, -CC-, -CO-, -COO-. -OCO-, -OCOO- or a gp. of formula (i) such that S and/or O atoms are not directly linked); one of the gps. R1, R2 can also be H, F, Cl, CN, NCS, CF3, OCF3 or OCHF2; Z1, Z2 = -Q-, -CH2CH2-, ethynyl, -CH2O-, -OCH2-, -COO-, -OCO-, -CH=N-, -CH2S-, -SCH2-, a single bond or 3-6C alkylene (opt. with one CH2 replaced by O, COO, OCO, CHHal or CHCN); Q = 1, 2-ethylene substd. with 2, 3 or 4 F atoms; m, n = 0, 1 or 2. More specifically at least one of the gps. A1-A4 = opt. F-substd. Phe, Cyc, pyrimidine-2, 5-diyl or pyridine-2, 5-diyl. USE/ADVANTAGE - (I) are useful as components of liq. crystal (LC) media for electro-optical display elements (claimed). Also claimed are LC media with at least 2 components, at least one of which is a cpd. (I), and electro-optical display elements and matrix LC displays contg. such media as dielectric. The invention provides new, stable LC cpds. (I) with comparatively low viscosity and medium dielectric anisotropy, which enable prodn. of LC media with a wide mesophase range and very good optical and dielectric anisotropy and specific resistance.