Fluorinated anthracenes, and their use in liquid-crystal mixtures

A compound of the formula (I)

• in which:
• L1, L2, L3, L4 and L5 are identical or different and are H or F, with the provisos that
• a) at least one of L1, L2, L3 L4 and L5 must be F
• b) if L1 is F, L3, L4 and L5 must be H
• c) if L4 or L5 is F, L1 and L2 must be H,
• R1 is a straight-chain or branched alkyl radical having from 1 to 16 carbon atoms or a straight-chain or branched alkenyl radical having from 2 to 16 carbon atoms, in which
• a) one or more non-adjacent and non-terminal CH2 groups may be replaced by —O—, —C(═O)O—, —O—C(═O)—, —O—C(═O)—O—, —C(═O)— or —Si(CH3)2—, and/or
• b) one CH2 group may be replaced by —C≡C—, cyclopropane-1,2-diyl, cyclobutane-1,3-diyl, cyclohexan-1,4-diyl or phenylene-1,4-diyl, and/or
• c) one or more H atoms may be replaced by F and/or Cl,
• R2 is hydrogen, F, Cl, CN, —NCS, CF3, CHF2, CH2F, OCF3, OCHF2, OCH2F, OCH2CF3, OCH═CF2 or a straight-chain or branched alkyl radical having from 1 to 12 carbon atoms or a straight-chain or branched alkenyl radical having from 2 to 12 carbon atoms, in which
• a) one or more non-adjacent and non-terminal CH2 groups may be replaced by —O—, —C(═O)O—, —O—C(═O)—, —O—C(═O)—O—, —C(═O)— or —Si(CH3)2—, and/or
• b) one CH2 group may be replaced by —C≡C—, cyclopropane-1,2-diyl or cyclobutane-1,3-diyl, and/or
• c) one or more H atoms may be replaced by F and/or Cl and/or the -M2-A2-R3 group, in which
• M2 is —CO—O—, —O—CO—, —CH2—O—, —O—CH2—, —CF2—O—, —O—CF2—, —CH═CH—, —CF═CF—, —C≡C—, —CH2—CH2—CO—O—, —O—CO—CH2—CH2—, —CH2—CH2—, —CF2—CF2—, —(CH2)4—, —OC(═O)CF═CF— or a single bond,
• A2 is 1,4-phenylene, in which one or two H atoms may be replaced by F, Cl, CN and/or OCF3 or up to three H atoms may be replaced by F, 1,4-cyclohexylene, in which one or two H atoms may be replaced by CH3 and/or F, 1-cyclohexene-1,4-diyl, in which one H atom may be replaced by CH3 or F, or 1,3-dioxane-2,5-diyl,
• R3 has the same possible meanings as R2, with the exception of -M2-A2-R3,