Patent ID: 8197709

Claim:
A compound of formula I in which B 1 denotes —CF 2 O—, —CH 2 O—, —CH 2 —CH 2 —, —CF 2 CF 2 —, —CH 2 CF 2 —, —CH═CH—, —CF═CF—, —CF═CH—, —C≡C—, or —(CO)O—, B 2 denotes —CF 2 O—, Z denotes F, Cl, SCN, NCS, CN, OCN, NCO, trifluoromethyl or trifluoromethoxy, X 1-4 independently of one another, denote F, Cl, or H, Y 1-6 independently of one another, denote H, F, Cl or T, L 1-6 independently of one another, denote H or T, T denotes alkyl, alkoxy, alkenyl, alkenyloxy or alkynyl having up to 6 carbon atoms, R denotes an unsubstituted alkyl radical having 1 to 15 C atoms, in which one or more CH 2 groups are optionally 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, or denotes F, Cl, Br, CN, CF 3 , OCF 3 , SCN, NCS or SF 5 , m denotes 2, 3 or 4, and n denotes 0, 1 or 2, o denotes 1, where m+n+o=3 or 4.