Optically-active oxirane deriv. liq crystal dopants - have fast switching times and are useful as helix compensation additives, etc.

摘要

Novel optically active mesogenic structured oxiran derivs. of formula (I), liq. crystal mixts. contg. (I) as dopant and electro-optical switching or display elements contg. such liq. crystal mixts., are claimed. In (I), R is opt. branched 6-12 alk(en)yl, opt. contg. an asymmetric C atom; M is -O-, -S-, -O.CO-, -CO.O- or -CO-; A is a gp. of formula (II)-(XIV) in which the phenylene rings can have one or two F atoms as substits.; X is MeOCH2CH2OCH2O-, alkoxy, alkylcarbonyloxy, halogen, trialkylsilyl or tetrahydropyranyl; Y is -CH2- or -CO-; n is 1-10; and k is 0 or 1. USE/ADVANTAGE - (I) are esp. useful at 0.05-70 (esp. 0.1-50) wt.% as dopants in tilted, smectic phases, converting these to ferroelectric phases, spontaneous polarisation valves are in the range 1-15 nC/cm2 at 10 mol.% doping and 25 deg.C extrapolating to valves of 10-150 nC/cm2 for pure (I). Switching times for the mixts. at 25 deg.C with 10 mol.% (I) dosage are often below 100 microsecs. at +/- 10 V/micron switch voltage. Also, (I) can induce very low pitch helices, making them suitable for helix compensation in liq. crystal mixts. (I) also give phases with high electrocline coeffts.