Trifluoromethylene compounds

A trifluoromethylene compound of the formula I ##STR10## in which R.sup.1 is an alkyl or alkenyl radical having 1 to 15 C atoms which is unsubstituted, monosubstituted by CN, CF.sub.3 or halogen, wherein one or more CH.sub.2 groups, in each case independently of one another, can be-replaced by --O--, ##STR11## --CO--, --CO--O--, --O--CO-- or --O--CO--O-- in a manner such that O atoms are not linked directly to one another,

• A.sup.1 is a
• (a) trans-1,4-cyclohexylene radical in which one or more non-adjacent CH.sub.2 groups may be optionally replaced by --O-- and/or --S--,
• (b) 1,4-phenylene radical, in which one or two CH groups may optionally be replaced by N,
• (c) radical from the group consisting of 1,4-cyclohexenylene, 1,3-cyclobutylene, 1,4-bicyclo(2,2,2)octylene, piperidine-1,4-diyl,
• naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl,
• where the radicals (a) and (b) may be substituted by CN or fluorine,
• Z.sup.1 is --CO--O--, --O--CO--, --CH.sub.2 --, OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --CH.dbd.CH--, --C.tbd.C-- or a single bond and
• m is 1, 2 or 3.