摘要:
Compounds of the formula (I) where: X1 is H or F G1-G2 is —CH2—CH— or CH═C— R1, R2 are a) H b) the M2-A2-R5 moiety c) for example, a straight-chain or branched alkyl radical having from 1 to 16 carbon atoms R3 and R4 are each, for example, H, the M2-A2-R5 moiety or a straight-chain or branched alkyl or alkyloxy radical having from 1 to 16 carbon atoms A2 is, for example, 1,4-phenylene, with the provisos that a) when R2 is not H, R1 and R3 have to be H, b) when R2 is H, R4 must not have the definitions c) or d), c) R1, R2, R3 and R4 must not at the same time be H.
摘要:
Compounds of the formula (I), liquid-crystal mixtures comprising these compounds, and their use in liquid-crystal displays: in which R1 is H, F, CF3, OCF3, OCF2H, OCFH2, an alkyl radical or alkyloxy radical or an alkenyl radical or alkenyloxy radical; R2 is H, an alkyl radical or alkyloxy radical or an alkenyl radical or alkenyloxy radical M1 is —C(═O)O—, —OC(═O)—, —CH2O—, —OCH2—, —OCF2—, —CF2O—, —C≡C—, —CH2CH2—, —CF2CF2—, —CF═CFC(═O)O— or a single bond M2 is —C(═O)O—, —OC(═O)—, —CH2O—, —OCH2—, —CH2CH2—, —CF2CF2— or a single bond; A1 and A2 are &agr;-1,4-diyl, unsubstituted or mono- or disubstituted by F; where &agr; is: phenylene, cyclohexane, 1-cyclohexene or 1,3-dioxane-2,5-diyl; m and n are zero or 1; m+n=0 or 1 L1, L2, L3, L4 and L5 are H or F.
摘要:
A ferroelectric liquid crystal mixture, especially useful for operation in the &tgr;Vmin−mode, comprises a 5-Arylindane derivative of the formula (I), wherein Y is CH, CF or N and R1(—A1—M1)a(—A2—M2)b—, (M3—A3—)cR2 are mesogenic groups.
摘要:
1,8-Difluoroisoquinoline derivatives of the formula (I)R.sup.1 (--M.sup.1).sub.a (--A.sup.1 --M.sup.2).sub.b (--A.sup.2 --M.sup.3).sub.c --B(--M.sup.4 --A.sup.3).sub.d (--M.sup.5 --A.sup.4).sub.e (--M.sup.6).sub.f --R.sup.2 (I)in which the symbols and indices have the following meanings: the group B is ##STR1## R.sup.1 and R.sup.2 are, for example, alkyl radicals having 1 to 20 carbon atoms;M.sup.1, M.sup.2, M.sup.3, M.sup.4, M.sup.5 and M.sup.6 are, for example, --O--, --CO--O--, --O--CO-- or a single bond;A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are, for example, 1,4-phenylene, pyrimidine-2,5-diyl or trans-1,4-cyclohexylene, anda, b, c, d, e and f are zero or one, with the proviso that the sum of b, c, d and e is 0, 1 or 2.The compounds of the formula (I) are colorless in the pure state and generally form liquid-crystalline mesophases in a temperature range which is favorably located for electro-optical use. They are stable chemically, thermally and to light.
摘要:
Compounds of the formula (I) R.sup.1 --(A.sup.1).sub.a (--M.sup.1).sub.b --(--A.sup.2).sub.c (--M.sup.2).sub.d (--A.sup.3).sub.e (--M.sup.3).sub.f (--A.sup.4).sub.g --H(I) in which the symbols and indices have the following meanings: R.sup.1 is B or a straight-chain or branched alkyl radical having 1 to 22 carbon atoms (with or without an asymmetrical carbon atom) in which, in addition, it is possible for one or two non-adjacent --CH.sub.2 -- groups to be replaced by --O--, --S--, --CO--, --CO--O--, --O--CO--, --CO--S--, --S--CO--, --O--CO--O--, --CH.dbd.CH--, --C.tbd.C--, .DELTA. or --Si(CH.sub.3).sub.2 --, and in which, in addition, one or more hydrogen atoms of the alkyl radical may be substituted by F, Cl, Br or CN, or is a chiral group, for example an epoxide, a dioxolane or a cyclic lactone, --(A.sup.1).sub.a (--M.sup.1).sub.b --(--A.sup.2).sub.c (--M.sup.2).sub.d (--A.sup.3).sub.e (--M.sup.3).sub.f (--A.sup.4).sub.g -- is a system comprising 1 to 4 rings (cyclohexane, aromatic or heterocyclic), it being possible for the system to be linked in different ways. The compounds according to the invention increase the response speed of liquid-crystal mixtures.
摘要:
The present invention relates to the novel compound 4-hydroxy-2,3,5-trifluorobenzoic acid and to a process for preparing this novel substance by reacting 2,3,4,5-tetrafluorobenzoic acid at elevated temperature with a basic compound dissolved and/or suspended in water, adding, if desired, a fluoride scavenger, bringing the resulting reaction mixture to a pH of 0 to 6 by addition of an acid, and isolating the 4-hydroxy-2,3,5-trifluorobenzoic acid formed.
摘要:
Cyclohexylphenylpyrimidines of the formula (I) ##STR1## in which R.sup.1 is straight-chain or branched, chiral or achiral alkyl or alkenyl having 2 to 16 carbon atoms, in which one or two nonadjacent --CH.sub.2 -- groups may be replaced by --0--, --S--, --CO--, --COO--, --OCO--, --Si(CH.sub.3).sub.2 -- or --C(CH.sub.3).sub.2 --, and in which one or more hydrogen atoms of the alkyl or alkenyl radical may be replaced by fluorine atoms, and in which the terminal CH.sub.3 group of the alkyl may also be replaced by ##STR2## R.sup.2 is straight-chain or branched, chiral or achiral alkyl having 1 to 10 carbon atoms,are particularly suitable components for ferroelectric liquid-crystal mixtures since they result in favorable properties, such as, for example, high contrast, when used in electrooptical switching and display devices.
摘要:
The novel silylalkyl or silylalkenyl compounds correspond to the general formula (I) ##STR1## Here the symbols A.sup.1, A.sup.2, A.sup.3 denote aromatic or heteroaromatic molecular units such as 1,4-phenylene or pyrimidine-2,5-diyl which are combined via a single bond (for k, m=0) or via functional groups M.sup.1,M.sup.2 such as CO--O or CH.sub.2 --O; j, k, l, m, n are zero or 1 (j+l+n=2 or 3). The radicals R.sup.2, R.sup.3, R.sup.4, R.sup.5 are hydrogen or alkyl/alkenyl, cycloalkyl, and the radicals R.sup.6, R.sup.7, R.sup.8 have a comparable meaning (hydrogen); R.sup.1 is alkyl/alkenyl or one of the substituents known from LC chemistry such as an .alpha.-haloalkanoic radical. In some cases compounds have wide and polymorphous liquid crystalline phases.
摘要:
Liquid-crystalline, 1-substituted piperidine-4-carboxylic acid esters, process for their preparation, and their use in liquid-crystalline mixturesThe novel 1-substituted piperidine-4-carboxylic acid esters of the general formula (I) ##STR1## are liquid-crystalline and exhibit, in particular, S.sub.c or S.sub.c * phases. In this formula, R.sup.1 or R.sup.2 is a radical of the general formula (II) ##STR2## in which the rings are aromatic, heteroaromatic or optionally heteratom-containing cycloaliphatic molecular components, such as 1,4-phenylene, pyrimidine-2,5-diyl or trans-1,4-cyclohexylene, which are linked via a single bond (in the case where n and p=zero) or via functional groups Z.sub.1 or Z.sub.2 such as CO- or CH.sub.2 -O, and in which k, n, m, p and q are zero or 1, where k+m+p is at least 1 and p=zero when m=zero. The other radical R.sup.1 or R.sup.2 is an optionally substituted straight-chain or branched alkyl group having 1 to 20 carbon atoms, X.sub.1 denotes, S, phenylenoxy or CH.sub.2, and X.sub.2 denotes O or phenylenoxy.
摘要:
Liquid-crystalline phenylpyrimidinyl cyclohexanecarboxylates having a smectic phase, a process for their preparation, and their use in liquid-crystal mixtures The phenylpyrimidinyl trans-cyclohexanecarboxylates of the general formula ##STR1## form a smectic C phase besides a relatively broad nematic phase when R.sup.1 denotes an alkyl radical having 10 to 16 carbon atoms, in particular 11 to 16 carbon atoms, or an alkoxy radical having 8 to 14 carbon atoms, and R.sup.2 denotes an alkyl radical having 2 to 9 carbon atoms. They are therefore particularly suitable as components of liquid-crystalline mixtures having a smectic C phase since they induce a relatively broad nematic phase or extend a narrow nematic phase which is present and extend the temperature range of the smectic C phase to low temperatures, but in particular to high temperatures.