Liquid-crystalline compounds, and liquid-crystalline medium

摘要

A liquid-crystalline medium based on a mixture of polar compounds of positive dielectric anisotropy, including one or more compounds of the general formula I: in which, R is H, an alkyl or alkenyl radical having 1 or 2 to 15 carbon atoms respectively which is unsubstituted, monosubstituted by CN or CF. or at least monosubstituted by halogen, where one or more CH2 groups in these radicals may also, in each case independently of one another, be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, or -O-CO-O- in such a way that O atoms are not linked directly to one another, m is 0 or 1, n is 0, 1 or 2, and m+n is 1, 2 or 3.