| abstract |
Liquid-crystalline compounds of the formula I, wherein one of the two radicals RC n F 2n + 1 with n = 1 to 15 and the rest R is an unsubstituted or at least one halogen-substituted alkyl radical having 1 to 15 carbon atoms, wherein in these radicals also one or more C 2 groups may each be independently replaced by -O-, so that O atoms do not directly with each other are linked A 1 and A 2 each independently (a) trans-1,4-cyclohexylene radical, in which also one or more non-adjacent CH 2 groups may be replaced by -O- and / or -S-, (b) 1,4-phenylene radical, in which also one or two CH groups may be replaced by N, (c) radical from the group consisting of 1,4-cyclohexenylene, 1,4-bicyclo (2,2,2) octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6- diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, where radicals (a) and (b) may be substituted by fluorine, Each of Z 1 and Z 2 independently represents -CO-O-, -O-CO-, -CH 2 O-, -OCH 2 -, -CH 2 CH 2 -, - (CH 2 ) 4 -, -CH = CH -CH 2 CH 2 -, -CH = CH-, C≡C- or a single bond, X and Y are each independently H, F or Cl, s and o are each independently 0 or 1, where s + o ≧ 1, and m 1 or 2 with the proviso that connections where at least one of ... |