Patent ID: 7335403

Claim:
A liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy, comprising a compound of formula I in which R 0 and R 1 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms, which is unsubstituted, monosubstituted by CN or CF 3 , or at least monosubstituted by halogen, in which optionally one or more CH 2 groups are replaced by —O—, —S—, —C≡C—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, A 1 a) denotes a 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non-adjacent CH 2 groups are optionally replaced by —O— or —S—, b) denotes a 1,4—phenylene radical, in which one or two CH groups are optionally replaced by N, c) denotes piperidine-1,4-diyl-, 1,4-bicyclo[2.2.2]octylene-, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl or fluorene-2,7-diyl, where A 1 is optionally mono- or polysubstituted by halogen atoms, Z 1 denotes —CO—O—, —O—CO—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CH 2 CH 2 , —(CH 2 ) 4 —, —C 2 F 4 —, —CH 2 CF 2 —, —CF 2 CH 2 —, —CF═CF—, —CH═CF—, —CF═CH—, —CH═CH—, —C≡C— or a single bond, and m denotes 0, 1 or 2.