Optically active compounds of the formula ##STR1## wherein n stands for the number 0 or 1; Z.sup.1 is a single covalent bond or --CH.sub.2 CH.sub.2 --; Z.sup.2 is a single covalent bond, --CH.sub.2 CH.sub.2 --, --CH.sub.2 O--, --OCH.sub.2 --, --COO-- or --OOC--; rings A.sup.1 and A.sup.2 each independently represent trans-1,4-cyclohexylene or optionally halogen-, cyano- and/or methyl-substituted 1,4-phenylene in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; R.sup.2 is a group R.sup.4 or a group of the formula ##STR2## R.sup.4 is cyano, halogen, --OCY.sup.1 F.sub.2, --CY.sup.1 F.sub.2 or an alkyl group in which optionally one >CH--CH< is replaced by >C.dbd.C< and/or optionally one methylene group or two non-adjacent methylene groups is/are replaced by --O--, --COO-- and/or --OOC-- and/or optionally one methylene group is replaced by --CHY.sup.2 --; Y.sup.1 is hydrogen or fluorine; Y.sup.2 is halogen, cyano or methyl; R.sup.1 and R.sup.3 denote alkyl in which optionally one >CH--CH< is replaced by >C.dbd.C< and/or optionally one methylene group or two non-adjacent methylene groups is/are replaced by --O-- and/or optionally one or more hydrogen atoms is/are replaced by fluorine; and (S*) and (R*) denote the relative configurations of the chiral carbon atoms, as well as liquid crystalline mixtures which contain such compounds and their use for optical and electro-optic purposes.
公式为 ##STR1## 的光学活性化合物,其中n代表数字0或1;Z.sup.1是单个共价键或--CH.sub.2 CH.sub.2 --;Z.sup.2是单个共价键,--CH.sub.2 CH.sub.2 --,--CH.sub.2 O--,--OCH.sub.2 --,--COO--或--OOC--;环A.sup.1和A.sup.2各自独立地表示反式1,4-
环己烯或选择性卤素,
氰基和/或甲基取代的1,4-苯基,在其中选择性地1个CH基或2个CH基被氮取代;R.sup.2是R.sup.4基团或式子##STR2##的基团,其中R.sup.4是
氰基,卤素,--OCY.sup.1 F.sub.2,--CY.sup.1 F.sub.2或烷基基团,在其中选择性地一个>CH--CH<被>C.dbd.C<取代和/或选择性地一个亚甲基基团或两个不相邻的亚甲基基团被--O--,--COO--和/或--OOC--取代和/或选择性地一个亚甲基基团被--CHY.sup.2 --取代;Y.sup.1是氢或
氟;Y.sup.2是卤素,
氰基或甲基;R.sup.1和R.sup.3表示烷基,在其中选择性地一个>CH--CH<被>C.dbd.C<取代和/或选择性地一个亚甲基基团或两个不相邻的亚甲基基团被--O--取代和/或选择性地一个或多个氢原子被
氟取代;以及包含这种化合物的液晶混合物及其用于光学和电光目的的用途。