LIQUID-CRYSTAL COMPOUNDS

摘要

Described are liquid-crystal compounds of formula (I), in which R may be H, an alkyl or alkylene group with 1 to 15 C-atoms which is unsubstituted or which is substituted with a single CN or CF3 group or with at least one halogen atom, whereby one or more CH2 groups in these alkyl or alkylene groups may be replaced, independently of each other, by -O-, -S-, - -, -CO-, -CO-O-, O-CO- or -O-CO-O in such a way that O-atoms are not bonded directly to each other; Z1 and Z, independently of each other, may be -CH2CH2-, -CH=CH-, -C=C- or a single bond, whereby one of the groups Z1 and Z may also be -(CH2)4 or -CH=CH-CH2CH2-; A and A1, independently of each other, may be the trans-1,4-cyclohexylene group (in which one or two non-adjacent CH2 groups may be replaced by -O-), an unsubstituted 1,4-phenylene group or a 1,4-phenylene group substituted with one or two F and/or Cl atoms, wherein one or two CH groups may be replaced by N; m may be 0, 1, 2 or 3; o and s may be 0, 1 or 2, with the provision that s + o >/= 2; W may be -O-, -COO- or a single bond; Q may be -O-, -CH=CH- or a single bond; r may be from 1 to 7; t may be from 0 to 7; and Y may be F, Cl, CF3, OCF3, CHF2, OCHF2 or OCH2F. Such compounds are suitable for use as components of liquid-crystal media.