| 摘要 |
The invention relates to difluoroacetonitrile derivatives of formula (I), R<1>-A<1>-Z<1>-(A<2>-Z<2>)m-A<3>-CF2-CN in which A<1>, A<2> and A<3> are mutually independently (a) a trans 1,4-cyclohexylene radical in which one or more non-adjacent CH2 groups may be substituted by -O- and/or -S-, (b) a 1,4-phenylene radical in which one or two CH groups may be substituted by N, (c) a radical from the group 1,3-cyclobutylene, 1,3-bicyclo (1,1,1)pentylene, 1,4-cyclohexenylene, 1,4-bicyclo (2,2,2)octylene, piperidine-1,4-diyl, naphthaline-2,6-diyl, decahydronaphthaline-2,6-diyl and 1,2,3,4-tetrahydronaphthaline-2,6-diyl, in which radicals (a) and (b) may be substituted by CN or halogen, R<1> is an alkyl or alkenyl radical which is unsubstituted or simply substituted by CN, halogen or CF3 with up to 15 C atoms, whereby in these radicals one or more CH2 groups may be mutually independently substituted by -S-, -O-, -( alpha )-, -( beta )-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that S and/or O atoms are not directly interlinked, Z<1> and Z<2> are mutually independently -CH2CH2-, -C=C-, -CH2O-, -OCH2-, -CO-O-, -CH=N-, -N=CH-, -CH2S-, -SCH2-, a single bond or an alkylene group with 3 to 6 C atoms, in which one CH2 group may be substituted by -O-, -CO-, -CO-O-, -O-CO-, -CH halogen- or -CHCN-, and m is O, 1 or 2, and their use as components of liquid crystal media for electro-optical displays. |
