Liquid crystal compounds, mixtures and devices

摘要

The invention concerns novel liquid crystal compounds of general formula I. These compounds may be used by themselves or they may be mixed with other liquid crystal compounds to give useful liquid crystal mixtures which may then be used in liquid crystal devices. The materials exhibit smectic mesophases and may therefore be used in ferroelectric, ferrielectric, antiferroelectric, thermochromic and electroclinic devices. They may also be used as long pitch materials. [R is alkyl, alkoxy or alkenyl and may contain 1-20 carbon atoms; A, B, C, D are independantly phenyl, cyclohexyl, pyridyl or pyrimidyl; A may also be dioxanyl, naphthyl or thiophene; b is 0, 1 or 2; c is 0 or 1; K, L, M, N are independantly halogens; (k), (l), (m), (n), are independantly 0, 1, 2, 3, or 4; X is OCO, COO, OCH2, CH2O, CH2, CH2CH2; Y is OCO, COO, OOC, OCH2, CH2O CH2; and J is an end group of formula II (where Z is halogen, C1-C3 alkyl, CN, CF3, CHF2 or H; R1 is a linear or branched alkyl group containing 1 - 15 carbon atoms or H; W is a linear or branched alkyl group containing 1-5 carbon atoms or H); excluding compounds where R is alkoxy, A=B=D = phenyl, K=F, (k)=2, (l)=(n)=0. b=1, c=0, X = OOC, Y = OOC, Z=Cl, R1 = CH2CH(CH3)2, W=H.