Liquid crystal mixtures comprising one or more compounds of formula (I), wherein R 1 is H or a
straight chain or branched chain
alkyl group of 1 to 20 carbon atoms or a
straight chain or branched chain alkenyl group of 2 to 20 carbon atoms, wherein in both cases, optionally one -CH 2 -group replaced by cyclohexa-1,4-diyl, or 1 or 2 -CH 2 -group, if not adjacent to
nitrogen (N), optionally replaced by -O-, or by -C(=O)-, -Si(CH 3 ) 2 - replace; and / or one or more H on the
alkyl or alkenyl is optionally replaced by F or CH 3 alternative, R 2 Represents a) H or F; b) straight-chain or branched-chain
alkyl of 1 to 20 carbon atoms or straight-chain or branched alkenyl of 2 to 20 carbon atoms, wherein in both cases, 1 or 2 -CH 2 - optionally replaced by -O-, -C(=O)O-, -Si(CH 3 ) 2 - Replacement, and / or one or more H on the alkyl or alkenyl group is replaced by F or CH 3 Replacement; c) group (a), wherein independently of the meanings of formula (I), R 3 , R 4 , R 5 , R 6 independently of each other is an alkyl group of 1-8 carbon atoms, M 1 , M 2 Each independently represents a
single bond, -OC(=O), -C(=O)O-, -OCH 2 -, -NH-, A is a) a straight-chain or
branched alkane-α, ω-diyl group of 1 to 20 carbon atoms or a straight-chain or branched
alkene-α, ω of 2 to 20 carbon atoms - Diyl group, if not with M 1 / 2 Adjacent, optional 1 or 2 non-adjacent -CH 2 -may be replaced by -O-; b) a group -C(=Y)-, wherein Y is CH-Z, and Z is
benzene-1,4-diyl optionally substituted by 1 to 3
halogen atoms, An alkyl or
alkoxy group of 1 to 4 carbon atoms, with the proviso that M 1 and M 2 is -C(=O)O- and -OC(=O)-; c) the group -CHY, wherein Y is CH 2 -Z, and Z is
benzene-1,4-diyl optionally substituted by 1 to 3
halogen atoms, an alkyl or
alkoxy group of 1 to 4 carbon atoms, with the proviso that M 1 and M 2 Be -C(=O)O- and -OC(=O)-; d) group (b), wherein p, q are 0, 1 or 2, p+q≥1; M 3 is a
single bond or -OC(=O)-, -C(=O)O-, -OCH 2 -, -CH 2 O-, -C≡C-, -CH 2 CH 2 -, -CH 2 CH 2 CH 2 CH 2 -, groups (c) and (d) independently of each other are
benzene-1,4-diyl optionally substituted by 1, 2 or 3 F, or optionally substituted by 1 CN, CH 3 Or cyclohexa-1,4-diyl substituted by F, or
pyrimidine-2,5-diyl optionally substituted by 1 F,
pyridine-2,5-diyl optionally substituted by 1 F , or
naphthalene-2,6-diyl optionally substituted by 1, 2 or 3 Fs, or 1,2,3,4-tetrahydronaphthalene-2,6-diyl (the aromatic ring is optionally substituted by 1, 2 or 3 F), or
decalin-2,6-diyl, or
indane-2,5(6)-diyl, or
fluorene-2,7-diyl, Or
phenanthrene-2,7-diyl, or 9,10-dihydrophenanthrene-2,7-diyl, or (1,3,4)-thiadiazole-2,5-diyl, or (1, 3)
Thiazole-2,5-diyl, or (1,3)
thiazole-2,4-diyl, or
thiophene-2,4-diyl, or
thiophene-2,5-diyl, or (1, 3) Dioxane-2,5-diyl, or
piperidine-1,4-diyl, or
piperazine-1,4-diyl; X is H, OH, a
straight chain of 1 to 20 carbon atoms Or branched chain alkyl or alkoxy, of which 1 or 2 -CH 2 - can be replaced by -O-, -C(=O)O-, -Si(CH 3 ) 2 - Replacement, optionally one or more hydrogens are replaced by F or CH 3 Substitution; m is 0 or 1, X and M 1 -(A) m -M 2 -R 2 Together they can constitute a) a 4-16-membered ring optionally substituted by an alkyl group of 1-15 carbon atoms, b) a combination of two directly connected or spiro-connected 4-16-membered rings independently connected to each other, optionally substituted by
Alkyl substitution of 1 to 15 carbon atoms, regardless of which of the three cases, the rings can be independently of each other carbocycles or carbocycles containing
boron,
nitrogen,
oxygen or
sulfur heteroatoms.