1,2-DISUBSTITUTED 2,6-DIFLUOROBENZENE COMPOUNDS AND LIQUID CRYSTAL MEDIA

摘要

Disclosed are 1,4-disubstituted 2,6-difluorobenzene compounds of the formula (I), in which R is an unsubstituted alkyl or alkenyl residue with 1-15 C-atoms or an alkyl or alkenyl group with 1-15 C-atoms substituted with at least one halogen residue, whereby one or more CH2 groups can be replaced, independently of each other, by -O-, -S-, ( alpha ), ( beta ) -CO-, -CO-O-, -O-CO- or -O-CO-O in such a way that O-atoms are not directly bound to each other, A<1> and A<2>, independently of each other, are (a) a trans-1,4-cyclohexylene residue in which one or more non-adjacent CH2 groups can be replaced by -O- and/or -S-, (b) a 1,4-phenylene residue in which one or two CH groups can be replaced by N, (c) a 1,4-cyclohexenylene, 1,4-bicyclo(2,2,2)-octylene, piperidine-1,4-diyl, naphthalene-2,6-dyil, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl residue, whereby residues (a) and (b) can be substituted with CN or one or two fluorine atoms, Z<1> and Z<2>, independently of each other, are -CO-O, -O-CO-, -CH2O-, -OCH2-, -CH2CH2-, -CH=CH-, -C=C- or a single bond, m and n, independently of each other, are 0,1,2 or 3, (m + n) being 1,2 or 3, and X has the same meaning as R, or is F, Cl, -CF3, -OCF3, -OCF2H, -OC2F5, -CN or -NCS, with the provision that at least one of the residues Z1 and Z2 in the molecule is -CO-O-, -O-CO-, -CH2-O-, -OCH2-, -CH2CH2-, -CH=CH- or -C=C- and/or at least one of the residues A<1> and A<2> in the molecule is ( psi ) or ( delta ), and/or n is 1 or 2, whereby when -(Z<2>-A<2>)n=( epsilon ). X is F, Cl, -CF3, -OCF3, -OCF2H, -OC2F5, -CN or -NCS. Such compounds are suitable for use as components of liquid-crystal media.