Liquid-crystalline compounds

Abstract

A nematic liquid crystalline medium having at least two liquid crystalline components with at least one being of formula I ##STR1## wherein R is H, a straight-chain alkyl or alkenyl radical having 1 to 15 carbon atoms, it also being possible to replace one or more CH.sub.2 groups in these radicals, independently of one another, by --O--, --S--, ##STR2## --CO--, --CO--O--, --O--CO-- or --O--CO--O-- in such a way that oxygen atoms are not linked directly to one another, Z.sub.1 and Z are each, independently of one another, --CH.sub.2 --CH.sub.2 --, --CH.dbd.CH--, --C.tbd.C-- or a single bond, and one of the radicals Z.sup.1 and Z is alternatively --(CH.sub.2).sub.4 -- or --CH.dbd.CH--CH.sub.2 CH.sub.2 --, A and A.sup.1 are each, independently of one another, trans-1,4-cyclohexylene in which, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by --O--, or are 1,4-phenylene which is unsubstituted or monosubstituted or disubstituted by fluorine and/or Cl atoms and in which, in addition, one or two CH groups may be replaced by N, m is 0, 1, 2 or 3, o and s are 0, 1 or 2, where (s+o) is >2. These liquid crystalline media find use in electro-optical display elements.

Dependencies are inferred from the claim text.