Nematic compounds with a negative DC antisotropy, characterized by the formula I ##STR1## in which m=1 or 2, r is zero or 1 and m+r=1 or 2, and R.sup.1 and R.sup.2 are identical or different and are selected from alkyl and alkoxy groups each having 1-12 carbon atoms in a straight or branched chain, which may be chiral, Z is a bridge member selected from a single bond and the groups of the formulae --CH.sub.2 CH.sub.2 --, --OCH.sub.2 --, --O--CO-- or --CO--O--, one of the groups X and Y is selected from fluorine, chlorine, bromine and cyano and the other of the groups X and Y is selected from hydrogen, fluorine, chlorine, bromine and cyano, with the proviso that m=r=1 if X and Y are both cyano, are suitable as components for liquid crystal mixtures having an overall negative DC anisotropy, such as are required in particular for electro-optical displays of the type of guest/host displays or homotropic-nematic displays.
具有负直流反各向异性的向列相化合物,其特征由式I表示:##STR1## 其中m=1或2,r为零或1且m+r=1或2,R1和R2相同或不同,选择自直链或支链的具有1-12个碳原子的烷基和烷氧基,可能是手性的,Z是选择自单键和式--
CH2 --,--O --,--O--CO--或--CO--O--的桥接成员,X和Y中的一个选择自
氟,
氯,
溴和
氰基,另一个选择自氢,
氟,
氯,
溴和
氰基,但是如果X和Y都是
氰基,则m=r=1,适用作液晶混合物的组分,其具有整体负的直流反各向异性,特别是用于客体/主体显示或同向向列相显示的电光显示。