Fluorinated aromatic compounds and the use of the same in liquid crystal mixtures

A compound of the formula (I)

• where
• X is C═O,
• Y is H or F
• R1 and R2 are the same or different and are each hydrogen, or are 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 where
• a) one or more nonadjacent and nonterminal 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 hydrogen atoms may be replaced by F or Cl, and/or
• d) the terminal CH3 group may be replaced by one of the following chiral groups (optically active or racemic):
• where R3 is 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 each of which one or more nonadjacent and nonterminal CH2 groups may be replaced by —O— and/or one or more hydrogen atoms may be replaced by F or Cl,
• with the proviso where only one of R1 and R2 is a hydrogen,
• M1 and M2 are the same or different and are each —C(═O)—O—, —O—C(═O)—, —CH2—O—, —O—CH2—, —CF2—O—, —O—CF2—, —CH═CH—, —CF═CF—, —C≡C—, —CH2—CH2—C(═O)—O—, —O—C(═O)—CH2—CH2—, —CH2—CH2—, —CF2—CF2—, —(CH2)4— or a single bond,
• A1 and A2 are the same or different and are each 1,4-phenylene where one or two hydrogen atoms may be replaced by F, Cl or CN, pyridine-2,5-diyl where one hydrogen atom may be replaced by F, pyrimidine-2,5-diyl, 1,4-cyclohexylene where one or two hydrogen atoms may be replaced by CH3 or F, 1-cyclohexene-1,4-diyl where one hydrogen atom may be replaced by CH3 or F, or 1,3-dioxane-2,5-diyl,
• m and n are each independently 0 or 1, but in total not greater than 1.