Patent ID: 7135210

Claim:
A liquid-crystalline compound of the formula I: in which X 1 and X 2 are each, independently of one another, F, Cl, Br or I, or one of the radicals X 1 and X 2 is alternatively H, X 3 is F, Cl, CN, NCS, SF 5 , or a halogenated alkyl, alkoxy, alkenyl or alkenyloxy radical having 1 to 5 carbon atoms, Z 1 and Z 2 are each, independently of one another, —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═CH—, —C≡C— or a single bond, with the proviso that at least one of the bridges Z 1 and Z 2 is —CF 2 O— or —OCF 2 —, a is 0, 1 or 2, and L 1 to L 11 are each, independently of one another, H or F, provided that the compound contains at least one of the following structures: