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