1,4-disubstituted 2,6-difluorobenzene compounds, and a liquid-crystalline medium

摘要

1,4-disubstituted 2,6-difluorobenzene compound of formula IwhereinR is an alkyl or alkenyl radical,A1 and A2 are independently(a) a trans-1,4-cyclohexylene radical in which a CH2 group may be replaced by -O- and/or -S,(b) a 1,4-phenylene radical in which a CH group may be replaced by N,(c) 1,4-cyclohexenylene, 1,4-bicyclo(2,2,2)octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl,Z1 and Z2 are -CO-O-, -O-CO-, -CH2O-,-OCH2-, -CH2CH2-, -CH=CH-,-C=C-or a single bondm and n are 0, 1, 2 or 3,(m+n) is 1, 2 or 3,X is R or F, Cl, CF3, -OCF3, or -OCHF2, -OCF5, -CN or -NCSwith the provisos that at least one of the radicals A1 and A2 present in the molecule is and at least one of Z1 or Z2 is -COO-,are suitable as components of liquid-crystalline media.