Acetylene derivatives and liquid crystalline mixtures containing them.

摘要

The present invention relates to compounds of the general formula: in which R is an alkyl group having 1 to 12 carbon atoms or a group of the formula ; the ring A<1> is unsubstituted or fluorine-substituted 1,4-phenylene, pyridine-2,5-diyl or pyrimidine-2,5-diyl; the ring A<2> is trans-1,4-cyclohexylene or trans-1,3-dioxane-2,5-diyl; R<1> is an alkyl, alkenyl or alkoxyalkyl group having 1 to 12 or 2 to 12 carbon atoms; X<1> is fluorine, chlorine, bromine, trifluoromethyl, trifluoromethoxy or difluoromethoxy; and X<2> and X<3> are hydrogen or fluorine. The invention likewise relates to liquid-crystal mixtures containing such compounds, and to the use of such compounds and mixtures for electro-optical purposes.