| 摘要 |
The invention concerns 3,5-difluorobenzenes of general formula (I) in which the symbols and indices are defined as follows: R<1> is H, a straight-chain or branched-chain alkyl (with or without an asymmetric C-atom) with 1 to 15 C-atoms, where one or two non-adjacent CH2 groups may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH=CH-, -CC-, cyclopropane-1,2-diyl or -Si(CH3)2- and where one or more H-atoms in the alkyl group may be replaced by F, Cl or CN; A<1>, A<2> and A<3>, which may be the same or different are 1,4-phenylene, pyrazine-2,5-diyl, pyridine-2,5-diyl or pyrimidine-2,5-diyl in which one or two H-atoms may be replaced by F, trans-1,4-cyclohexylene, (1,3,4)-thiadiazole-2,5-diyl, 1,3-dioxane-2,5-diyl, naphthaline-2,6-diyl, bicyclo[2.2.2]octane-1,4-diyl or 1,3-dioxaborinane-2,5-diyl; M<1>, M<2>, which may be the same or different, are -CH2CH2-, -CH=CH-, -CC-, -CH2CH2CH2CH2-, -CH2CH2CH2-O-, -O-CH2CH2CH2-, -CH2CH2CO-O-, -O-CO-CH2CH2-, -CH2-O-, -O-CH2-, -CO-O- or -O-CO-; k, l, m, n, o are zero or one, provided that the sum k+m+o is greater than zero; with the following provisions: when k+m+o is one, X is -CH2CH2-, -CH=CH-, -CC-, -CH2CH2CH2CH2-, -CH2CH2CH2-O-, -O-CH2CH2CH2-, -CH2CH2CO-O-, O-CO-CH2CH2-, -CH2-O-, -O-CH2-, -CO-O- or -O-CO-; and when k+m+o is greater than one, X is -CH2CH2-, -CH=CH-, -CC-, -CH2CH2CH2CH2-, -CH2CH2CH2-O-, -O-CH2CH2CH2-, CH2CH2CO-O-, -O-CO-CH2CH2-, -CH2-O-, -O-CH2-, -CO-O-, -O-CO- or a single bond. The compounds described are suitable for use as components of nematic liquid-crystal mixtures. |
