Patent ID: 8211513

Claim:
A compound of formula I in which A 1 denotes 1,4-phenylene, which is optionally up to tetrasubstituted, independently of one another, by halogen, CN, CH 3 , CHF 2 , CH 2 F, OCH 3 , OCHF 2 or OCF 3 and in which 1-2 CH groups are optionally replaced by N, cyclohexene-1,4-diyl, in each of which 1-2 CH 2 groups are optionally replaced, independently of one another, by O or S and/or H may be replaced by F, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, 2,5-thiophenediyl or 2,5-selenophenediyl, Z 1 denotes a bonding unit selected from the group consisting of a single bond, CF 2 O, CH 2 CH 2 , CF 2 CH 2 , CF 2 CF 2 , CFHCFH, CFHCH 2 , (CO)O, CH 2 O, C≡C, CH═CH, CF═CH, and CF═CF; where asymmetrical bonding units may be oriented in either of both possible directions, and R 1 denotes an unsubstituted alkyl radical having 1 to 15 C atoms, in which one or more CH 2 groups may each be replaced, independently of one another, by —C≡C—, —CH═CH—, —CF═CF—, —CF═CH—, —CH═CF—, —(CO)O—, —O(CO)—, —(CO)— or —O— in such a way that O atoms are not linked directly to one another, H, F, Cl, Br, CN, CF 3 , OCF 3 , SCN, NCS or SF 5 .