Patent ID: 7678929

Claim:
A compound of formula I in which R 1 and R 2 each, independently of one another, denote H, halogen, —CN, —SCN, —SF 5 , —CF 3 , —CHF 2 , —CH 2 F, —OCF 3 , —OCHF 2 or an alkyl group having 1 to 15 C atoms, which is optionally monosubstituted by CN or CF 3 or at least monosubstituted by halogen and in which optionally one or more CH 2 groups, in each case independently of one another, are replaced by —O—, —S—, —CH═CH—, —CF═CF—, —CF═CH—, —CH═CF—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that neither O nor S atoms are linked directly to one another, >Y 1 —Y 2 — denotes >C═CH— or >CH—CH 2 —, L 1 and L 2 are both F, each, independently of one another, and, if present more than once, these also independently of one another, denote (a) a trans-1,4-cyclohexylene radical, in which one or two non-adjacent CH 2 groups are optionally replaced by —O— and/or —S, (b) a 1,4-cyclohexenylene radical, (c) a 1,4-phenylene radical, in which one or two non-adjacent CH groups are optionally replaced by N, (d) naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl, or (e) 1,4-bicyclo[2.2.2]octylene, 1,3-bicyclo[1.1.1]pentylene or spiro[3.3]heptane-2,6-diyl, wherein in (a) and (b), one or more —CH 2 — groups, independently of one another, are optionally replaced by a —CHF— or a —CF 2 — group, and in (c) and (d), one or more —CH═ groups, independently of one another, are optionally replaced by —CF═, —CCl═, —CBr═, —C(CN)═, —C(CH 3 )═, —C(CH 2 F)═, —C(CHF 2 )═, —C(OCH 3 )═, —C(OCHF 2 )═ or —C(OCF 3 )═, Z 1 and Z 2 each, independently of one another, and, if present more than once, these also independently of one another, denote a single bond, —CH 2 —CH 2 —, —CF 2 —CH 2 —, —CH 2 —CF 2 —, —CF 2 —CF 2 —, —CH═CH—, —CF═CF—, —CF═CH—, —CH═CF—, —C≡C—, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, or —OCF 2 —, or a combination of two of these groups, where no two O atoms are bonded to one another, and n and m each independently denote 0, 1, 2 or 3, where (n+m) denotes 0, 1, 2 or 3.