| 摘要 |
Compounds of general formula (I), wherein R signifies hydrogen, halogen, cyano, isothiocyanato, or alkyl, alkenyl or alkynyl with 1 to 15 carbon atoms, which is unsubstituted or substituted with at least one of halogen, cyano and/or trifluoromethyl and in which one or more non-adjacent -CH2- group(s) can be replaced by -O-, -S-, -CO-, -COO- and/or -OOC-; Q represents alkylene with 2 to 10 carbon atoms, which is unsubstituted or substituted with at least one fluorine and in which one -CH2- group can be replaced by -O-, -S-, -COO- or -OOC-, or -CH2-, -CF2-, -CHF- or a single covalent bond; A<1>, A<2>, A<3> each independently signify 1,4-phenylene, which is unsubstituted or substituted with at least one of halogen, cyano and/or methyl and in which, when it is unsubstituted, one or more -CH- groups can be replaced by nitrogen, or unsubstituted or cyano- or fluoro-substituted trans-1,4-cyclohexylene, or 1,4-cyclohexenylene, trans-1,3-dioxane-2,5-diyl or trans-1,3-dithiane-2,5-diyl; A<4> represents unsubstituted or cyano- or fluoro-substituted trans-1,4-cyclohexylene, or 1,4-cyclohexenylene, trans-1,3-dioxane-2,5-diyl, trans-1,3-dithiane-2,5-diyl or, when Q is different from a single covalent bond, also 1,4-phenylene, which is unsubstituted or substituted with at least one of halogen, cyano and/or methyl and in which, when it is unsubstituted, one or more -CH- groups can be replaced by nitrogen; X<1> represents bromine or chlorine; Z<1>, Z<2>, Z<3> each independently denote a single covalent bond, -CH2O-, -OCH2-, -CH2CH2-, -COO-, -OOC-, -C=C-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, the trans form of -CH=CH-, -CH=CHCH2O-, -OCH2CH=CH-, -CH=CH(CH2)2- or -(CH2)2CH=CH-; n, p each independently signify 0 or 1; R<2>, R<3> each independently represent hydrogen or fluorine, as well as liquid crystalline mixtures which contain such compounds and their use for electro-optical purposes. |
