DE19933175A1 - New sulfur pentafluoride derivatives with para-linked benzene rings, one of which is fluorine-substituted, useful as components of liquid crystal media for LC and electro-optical displays - Google Patents

Abstract

Sulfur pentafluoride derivatives with at least 2 benzene rings linked at the para-positions (optionally with various linking groups), in which one terminal ring carries the SF5 group at its other (terminal) para-position and the other carries 1 or 2 fluorine substituents and possibly another substituent at its other (terminal) para-position. New sulfur pentafluoride derivatives of formula (I): R<1> = H, 1-12C alkyl or 2-12C alkenyl (both optionally substituted with one CN or CF3 group or at least one halogen atom and optionally with one or more non-adjacent CH2 groups replaced by -O-, -S-, -CO-, -CH=CH-, cyclobutane-1,3-diyl, -COO-, -OCO- or -OCOO-); A<1>, A<2> = (a) trans-1,4-cyclohexylene (optionally with one or more non-adjacent CH2 replaced by -O- and/or -S-), (b) 1,4-phenylene (optionally with one or two CH groups replaced by N), (c) 1,4-bicyclo-(2.2.2)octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl or its decahydro- or 1,2,3,4-tetrahydro- derivatives, or (d) 1,4-cyclohexylene, in which groups (a), (b) and (d) may also be substituted with CN, Cl or F; L = H or F; Z<1>, Z<2> = -COO-, -OCO-, -CH2O-, -O-, -OCH2-, -CH2CH2-, -CF2CF2-, -CH=CH-, -C equivalent to C- or a single bond; n, m = 0, 1 or 2; (n + m) = 0, 1 or 2. Independent claims are also included for: (a) preferred compounds of formula (Ia) and (Ib); (b) liquid crystal (LC) media with at least two LC components, containing at least one compound (I); (c) LC display elements containing these LC media; (d) electro-optical display elements containing these LC media as the dielectric.

Description

The invention relates to new fluorocyclohexane derivatives of the formula I.

wherein
R ¹ H, an unsubstituted, an alkyl radical with 1-12 C atoms or alkenyl radical with 2-12 C atoms which is simply substituted by CN or CF ₃ or an at least monosubstituted by halogen, wherein one or more non-adjacent CH ₂ Groups each independently

can be replaced
A ¹ and A ²

• a) trans-cyclohexane-1,4-diyl radical, in which one or more non-adjacent CH ₂ groups can also be replaced by -O- and / or -S-,
• b) 1,4-phenylene radical, in which also one or two CH groups can be replaced by N,
• c) residue from the group 1,4-bicyclo (2,2,2) octylene, pipe ridin-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene 2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl,
• d) cyclohexane-1,4-diyl

where the radicals a), b) and d) can be substituted by CN, Cl or F,
LH or F
Z ¹

and Z ²

each independently of the other -CO-O-, -O-CO-, -CH ₂

O-, -O-, -O-CH ₂

, -CH ₂

CH ₂

, -CF ₂

CF ₂

-, -CH = CH-, -C∼C- or a single bond,
and
n and m 0, 1 or 2, where
n + m 0, 1 or 2
means.

The invention further relates to the use of these compounds as Components of liquid crystalline media as well as liquid crystal and electro optical display elements, the liquid-crystalline according to the invention Media included.

The compounds of the formula I can be liquid-crystalline as components Media are used, especially for displays based on the principle the twisted cell, the guest-host effect, the effect of the deformation erected phases DAP or ECB, Electrically controlled birefringence or based on the effect of dynamic scattering. So far for this Purpose-used substances always have certain disadvantages, for example show insufficient stability against the effects of heat, light or electrical fields, unfavorable elastic and / or dielectric Characteristics.

Similar phenyl sulfur pentafluoride derivatives are e.g. B. known from DE 37 21 268.  

The invention was based on the object, new stable liquid-crystalline or find mesogenic compounds as components liquid crystalline media, especially for TFT and STN displays, are suitable.

It has now been found that the compounds of the formula I are excellent as Components of liquid crystalline media are suitable. With her help read stable liquid-crystalline media, particularly suitable for TFT or STN displays. The new connections are emerging all characterized by a high thermal stability, which holds for a high " ratio "is advantageous and show at comparatively low rotation viscosity favorable values of the clearing points. The compounds of formula I. have a strong positive dielectric anisotropy with a high one optical anisotropy. They are still very good Solubility properties in various host mixtures.

With the provision of compounds of formula I becomes very general the range of liquid crystalline substances, which can be found under different application aspects for the production of liquid crystal liner mixtures are suitable, considerably widened.

The compounds of formula I have a wide range of uses Area. Depending on the selection of the substituents, these can Compounds serve as base materials from which liquid crystalline The majority of the media are composed; but it can also compounds of the formula I from liquid-crystalline base materials other classes of compounds, for example the dielectric and / or optical anisotropy of such a dielectric influence and / or around its threshold voltage and / or its Optimize viscosity.  

The compounds of the formula I are colorless in the pure state and form liquid crystalline mesophases in one for electro-optical use conveniently located temperature range. Chemical, thermal and against Light they are stable. Formula I also old isotopes of the in the Compounds of formula I occurring elements.

The invention thus relates to the compounds of the formula I and the use of these compounds as components of liquid crystalline Media. The invention also relates to liquid-crystalline media containing at least one compound of formula I and liquid crystal display elements, in particular electro-optical display elements, that contain such media.

Above and below, R ¹ , A ¹ , A ² , Z ¹ , Z ² , L, m and n have the meaning given, unless expressly stated otherwise.

For the sake of simplicity, Cyc in the following means 1,4-cyclohexy lenrest, Che a 1,4-cyclohexenylene residue, Dio a 1,3-dioxane-2,5- diyl residue, Dit a 1,3-dithiane-2,5-diyl residue, Phe a 1,4-phenylene residue, Pyd a pyridine-2,5-diyl radical, Pyr a pyrimidine-2,5-diyl radical and Bco one Bicyclo (2,2,2) octylene radical, where Cyc and / or Phe is unsubstituted or can be substituted one or more times by Cl, F or CN.

Formula I comprises the preferred compounds IA and IB:

wherein R ¹ , A ¹ , Z ¹ , m and L have the meaning given above.

Formula IA is particularly preferred.

In the compounds of the formula IA and IB, Z ¹ preferably denotes a single bond or -COO-, in particular a single bond. A ¹ in these compounds preferably denotes Phe and m preferably 0 or 1.

In the compounds of the formula IA, R ¹ preferably denotes straight-chain alkyl or alkoxy with 1 to 10 C atoms or alkenyl or alkenyloxy with 2 to 10 C atoms. R ¹ very particularly preferably denotes akenyl or alkenyloxy having 2 to 7 carbon atoms. The preferred meaning of m is 0 or 1, n is preferably 0.

A ¹ and A ² independently of one another are preferably Phe, Cyc, Che, Pyd, Pyr or Dio. The compounds of the formula I preferably contain no more than one of the radicals Bco, Pyd, Pyr, Dio or Dit.

The cyclohexene-1,4-diyl group preferably has the following structures:

If the ring A ¹ is present more than once, the two rings can have the same or different meanings. The same also applies to the bridge Z ¹ and to all other groups which occur several times in the compounds of the formula I.

Preference is also given to compounds of the formula I and all sub-formulas in which A ^{1 is} 1,4-phenylene which is mono- or disubstituted by F or CN.

Preferably A ¹ and A ²

Z ¹ and Z ² independently of one another are preferably -CH ₂ CH ₂ -, E- CH = CH-, -C∼C- or a single bond, particularly preferably a single bond or -C∼C-. Z ¹ very particularly preferably has the meaning of a single bond.

Compounds of the formula I are preferred which are characterized in that R ¹ denotes straight-chain alkyl or alkoxy having 1 to 10 C atoms or alkenyl having 2 to 10 C atoms and Z ^{1 has} the meaning of a single bond.

Compounds of the formula I, their group A ¹ and / or A ²

means represent special embodiments of the Invention.

The following group of compounds of sub-formulas I1 to I62 represents further preferred embodiments of the invention:

wherein R ¹ and L have the meaning given above.

If R ¹ in the formulas above and below denotes an alkyl radical and / or an alkoxy radical, this can be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and accordingly preferably means ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy, furthermore methyl , Octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

Oxaalkyl preferably means straight-chain 2-oxapropyl (= methoxy methyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxa heptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxa nonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R ^{1 is} an alkenyl radical, this can be straight-chain or branched. It is preferably straight-chain and has 2 to 10 carbon atoms. Accordingly, it means especially vinyl, prop-1-, or prop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent-4-enyl, hex -1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- or hept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-, 4-, 5-, 6-, 7- or non-8-enyl, Dec-1 -, 2-, 3-, 4-, 5-, 6-, 7-, 8- or Dec-9-enyl.

R ¹ particularly preferably denotes an alkenyl radical from the following group:

If R ^{1 is} an alkenyloxy radical, this can be straight-chain or branched. It is preferably straight-chain and has 2 to 10 carbon atoms.

It particularly preferably means a radical from the following group:

If R ^{1 is} an alkyl radical in which one CH ₂ group has been replaced by -O- and one has been replaced by -CO-, these are preferably adjacent. Thus, they contain an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. These are preferably straight-chain and have 2 to 6 carbon atoms.

Accordingly, they mean especially acetyloxy, propionyloxy, butyryloxy, Pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, Butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyl oxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, Butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxy carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxy carbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxycarbonyl) butyl.

If R ^{1 is} an alkyl radical in which a CH ₂ group is replaced by unsubstituted or substituted -CH = CH- and an adjacent CH ₂ group is replaced by CO or CO-O or O-CO-, this can be straight-chain or be branched. It is preferably straight-chain and has 4 to 13 carbon atoms. Accordingly, it means, in particular, acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxyheptyl, 8-acryloyloxyoctyl, 9-acryloyloxy nonyl, 10-acryloyloxydylyl, 1-methoxyloxydecyl -Methacryloyloxy ethyl, 3-methacryloyloxypropyl, 4-methacryloyloxybutyl, 5-methacryloyl oxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoxyctyl, 9-methacryloyloxynonyl.

If R ¹ is a monosubstituted by CN or CF ₃ alkyl or alkenyl radical, this radical is preferably straight-chain and the substitution by CN or CF ₃ in ω-position.

If R ^{1 is} an alkyl or alkenyl radical which is at least monosubstituted by halogen, this radical is preferably straight-chain and halogen is preferably F or Cl. In the case of multiple substitution, halogen is preferably F. The resulting residues also include perfluorinated residues. In the case of single substitution, the fluorine or chlorine substituent can be in any position, but preferably in the ω position.

Compounds of the formula I with branched wing group R ¹ can occasionally be important because of their better solubility in the customary liquid-crystalline base materials, but in particular as chiral dopants if they are optically active. Smectic compounds of this type are suitable as components for ferroelectric materials.

Branched groups of this type usually contain no more than one chain branch. Preferred branched radicals R ¹ are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentyloxy, 3-methylpentyloxy, 2-ethylhexyloxy, 1-methylhexyloxy, 1-methylheptyloxy.

Formula I includes both the racemates of these compounds and the optical antipodes and mixtures thereof.

Among these are compounds of formula I and the sub-formulas preferred those in which at least one of those contained therein Radicals has one of the preferred meanings indicated.

In the compounds of formula I are those stereoisomers preferred in which the rings Cyc and piperidine are trans-1,4-disubstituted are. Those of the above formulas, the one or contain several groups Pyd, Pyr and / or Dio, each enclose the two 2,5-position isomers.

The compounds of formula I are according to methods known per se presented as they are in the literature (e.g. in the standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart) are described and under reaction conditions that for the implementations mentioned are known and suitable.

You can do this from known, not mentioned here Make use of variants.  

The 4-substituted phenyl used as starting compounds sulfur pentafluorides can e.g. B. according to literature (W. A. Sheppard, J. Am. Chem. Soc. 84, 3064, 1962) can be obtained.

One starts from di (p-nitrophenyl) disulfide, from which one passes through Reacting with silver difluoride p-nitrophenyl sulfur pentafluoride receives the again as the starting compound for many 4-substituted phenyl sulfur Pentafluoride can serve.

If desired, the starting materials can also be formed in situ, such that they are not isolated from the reaction mixture, but rather immediately continues to react to the compounds of formula I.

The compounds of the invention can e.g. B. according to the following Reaction schemes are made:  

Scheme 1

Scheme 2

Scheme 3

Esters of the formula I can also be correspondingly esterified Carboxylic acids (or their reactive derivatives) with alcohols or Phenols (or their reactive derivatives) or according to the DCC Method (DCC = dicyclohexylcarbodiimide) can be obtained.

The corresponding carboxylic acids and alcohols or phenols are known or can be prepared in analogy to known methods become.

Suitable reactive derivatives of the carboxylic acids mentioned are especially the acid halides, especially the chlorides and bromides, furthermore the anhydrides, azides or esters, in particular alkyl esters with 1-4 C atoms in the alkyl group.  

As reactive derivatives of the alcohols or phenols mentioned come in particular the corresponding metal alcoholates or Phenolates, preferably an alkali metal such as Na or K, into consideration.

The esterification is advantageous in the presence of an inert solvent carried out. Particularly suitable are ethers such as diethyl ether, di-n- butyl ether, THF, dioxane or anisole, ketones such as acetone, butanone or Cyclohexanone, amides such as DMF or phosphoric acid hexamethyltriamide, Hydrocarbons such as benzene, toluene or xylene, halogenated hydrocarbons substances such as carbon tetrachloride or tetrachlorethylene and sulfoxides such as Dimethyl sulfoxide or sulfolane. Solvents immiscible with water can also be advantageous for azeotropic distillation of the Esterification water formed can be used. Occasionally can also an excess of an organic base, e.g. B. pyridine, quinoline or Triethylamine, can be used as a solvent for the esterification. The esterification can also be carried out in the absence of a solvent, e.g. B. by simply heating the components in the presence of sodium acetate. The reaction temperature is usually between -50 ° and + 250 °, preferably between -20 ° and + 80 °. At the esterification reactions are usually after these temperatures Ended 15 minutes to 48 hours.

The reaction conditions for the esterification depend in particular largely depends on the nature of the raw materials used. So will a free carboxylic acid with a free alcohol or phenol usually in the presence of a strong acid, for example a mineral acid such as Hydrochloric acid or sulfuric acid. A preferred response is the implementation of an acid anhydride or in particular one Acid chloride with an alcohol, preferably in a basic environment, where as bases in particular alkali metal hydroxides such as sodium or Potassium hydroxide, alkali metal carbonates or bicarbonates such as Sodium carbonate, sodium hydrogen carbonate, potassium carbonate or potassium hydrogen carbonate, alkali metal acetates such as sodium or potassium acetate, Alkaline earth metal hydroxides such as calcium hydroxide or organic bases such as Triethylamine, pyridine, lutidine, collidine or quinoline are important.  

Another preferred embodiment of the esterification is that the alcohol or the phenol first in the sodium or Potassium alcoholate or phenolate transferred, e.g. B. by treatment with ethanolic sodium or potassium hydroxide solution, this isolated and with an acid anhydride or in particular acid chloride.

Nitriles can be replaced by exchanging halogens with copper cyanide or Alkali cyanide can be obtained.

In a further process for the preparation of the compounds of the formula I in which Z ¹ and / or Z ^{2 is} -CH = CH-, an aryl halide is reacted with an olefin in the presence of a tertiary amine and a palladium catalyst (cf. RF Heck, Acc. Chem. Res. 12 (1979) 146). Suitable aryl halides are, for example, chlorides, bromides and iodides, in particular bromides and iodides. The tertiary amines required for the success of the coupling reaction, such as. B. triethylamine, are also suitable as solvents. Suitable palladium catalysts are, for example, its salts, in particular (Pd (II) acetate, with organic phosphorus (III) compounds such as, for example, triarylphosphanes. In the presence or absence of an inert solvent, temperatures between about 0 ° C. and 150 ° C., preferably between 20 ° C. and 100 ° C. Suitable solvents are, for example, nitriles such as acetonitrile or hydrocarbons such as benzene or toluene The aryl halides and olefins used as starting materials are commercially available in many cases or can be obtained from Processes known from the literature are produced, for example by halogenation of corresponding parent compounds or by elimination reactions on corresponding alcohols or halides.

In this way, stilbene derivatives can be produced, for example. The Stilbenes can still be made by implementing a 4-substituted benzaldehyde with an appropriate phosphorylide after Wittig. However, tolanes of the formula I can also be prepared by one uses monosubstituted acetylene instead of the olefin (synthesis 627 (1980) or Tetrahedron Lett. 27, 1171 (1986)).  

Furthermore, aryl halides can be coupled with aryl to couple aromatics tin compounds are implemented. These reactions are preferred with the addition of a catalyst such. B. a palladium (0) complex in inert solvents such as hydrocarbons at high temperatures, e.g. B. in boiling xylene, carried out under a protective gas.

Couplings of alkynyl compounds with aryl halides can be carried out analogously that of A. O. King, E. Negishi, F. J. Villani and A. Silveira in J. Org. Chem 43, 358 (1978).

Tolanes of the formula I, in which Z is -C∼C-, can also be obtained via the Fritsch-Buttenberg-Wechell rearrangement (Ann. 279, 319, 1984) be put in the 1,1-diaryl-2-halogenethylene are rearranged to diarylacetylenes in the presence of strong bases.

Tolanes of formula I can also be prepared by the the corresponding stilbene is brominated and then a dehydrohalo Submission to submission. You can do it in a known way, but not here Apply mentioned variants of this implementation.

Ethers of the formula I can be obtained by etherification of corresponding hydroxyl compounds, preferably corresponding phenols, the hydroxyl compound advantageously first being converted into a corresponding metal derivative, e.g. B. by treatment with NaH, NaNH ₂ , NaOH, KOH, Na ₂ CO ₃ or K ₂ CO _{3 is converted} into the corresponding alkali metal alcoholate or alkali metal phenolate. This can then be reacted with the appropriate alkyl halide, sulfonate or dialkyl sulfate, advantageously in an inert solvent such as. B. acetone, 1,2-dimetho xythan, DMF or dimethyl sulfoxide or with an excess of aqueous or aqueous alcoholic NaOH or KOH at temperatures between about 20 ° C and 100 ° C.

For the production of laterally substituted fluorine or chlorine compounds of the formula I corresponding aniline derivatives with sodium nitrite and either with tetrafluoroboric acid (to introduce an F atom) or with  Copper (I) chloride (to introduce a Cl atom) to the diazonium salt are implemented, which then thermally at temperatures of 100 ° -140 ° be decomposed.

Linking an aromatic core with a non-aromatic one Core or two non-aromatic nuclei are preferably obtained by Condensation of a lithium or organomagnesium compound with a ketone if there is an aliphatic group Z between the nuclei should.

The organometallic compounds are put through, for example Metal-halogen exchange (e.g. according to Org. React. 6, 339-366 (1951)) between the corresponding halogen compound and a lithium organic compound such as preferably tert-butyllithium or lithium Naphthalenide or by conversion with magnesium shavings.

The linking of two aromatic rings or aliphatic group Z with an aromatic ring is preferably carried out by Friedel-Crafts alkylation or acylation by reacting the corresponding aromatic compounds with Lewis acid catalysis. Appropriate Lewis acids are e.g. B. SnCl ₄ , ZnCl ₂ or especially AlCl ₃ and TiCl ₄ .

Furthermore, the connection of two aromatic rings can be made through the Ullmann reaction (e.g. Synthesis 1974, 9) between aryl iodides with Copper iodide, but preferably between an aryl-copper compound and an aryl iodide, or by the Gomberg-Bachmann reaction between an aryl diazonium salt and the corresponding aroma table connection (e.g. Org. React. 2, 224 (1944)). The Representation of the tolanes of formula I takes place, for. B. by implementing the corresponding arylhologenides with an acetylide in a basic Solvents with transition metal catalysis; preferred here Palladium catalysts are used, especially a mixture from bis (triphenylphosphine) palladium (II) chloride and copper iodide in piperidine as a solvent.  

In addition, the compounds of the formula I can be prepared by adding a compound which otherwise corresponds to the formula I Instead of H atoms, one or more reducible groups and / or Contains C-C bonds, reduced.

As reducible groups are preferably carbonyl groups, in particular keto groups, further z. B. free or esterified hydroxyl groups or aromatic halogen atoms. Preferred starting materials for the reduction are compounds corresponding to the formula I, but instead of a cyclohexane ring a cyclohexene ring or cyclohexanone ring and / or instead of a -CH ₂ CH ₂ group a -CH = CH group and / or instead of a -CH ₂ group contain a -CO group and / or instead of an H atom a free or a functionally modified (e.g. in the form of its p-toluenesulfonate) OH group.

The reduction can e.g. B. done by catalytic hydrogenation at temperatures between about 0 ° and about 200 ° and pressures between about 1 and 200 bar in an inert solvent, for. B. an alcohol such as methanol, ethanol or isopropanol, an ether such as tetrahydrofuran (THF) or dioxane, an ester such as tetrahydrofuran (THF) or dioxane, an ester such as ethyl acetate, a carboxylic acid such as acetic acid or a hydrocarbon such as cyclohexane. Suitable catalysts are suitably noble metals such as Pt or Pd, which can be used in the form of oxides (e.g. PtO ₂ , PdO), on a support (e.g. Pd on carbon, calcium carbonate or strontium carbonate) or in finely divided form .

Ketones can also by the methods of Clemmensen (with zinc, amalgamated zinc or tin and hydrochloric acid, expediently in aqueous alcoholic solution or in a heterogeneous phase with water / toluene at temperatures between about 80 and 120 °) or Wolff-Kishner (with hydrazine, expedient reduced in the presence of alkali such as KOH or NaOH in a high-boiling solvent such as diethylene glycol or triethylene glycol at temperatures between about 100 and 200 °) to the corresponding compounds of the formula I which contain alkyl groups and / or -CH ₂ CH ₂ bridges become.

Reductions with complex hydrides are also possible. For example, arylsulfonyloxy groups can be reductively removed with LiAlH ₄ , in particular p-toluenesulfonyloxymethyl groups can be reduced to methyl groups, expediently in an inert solvent such as diethyl ether or THF at temperatures between about 0 and 100 °. Double bonds can be hydrogenated with NaBH ₄ or tributyltin hydride in methanol.

The starting materials are either known or can be made in analogy be made to known compounds.

The liquid-crystalline media according to the invention preferably contain in addition to one or more compounds according to the invention as further Components 2 to 40, especially 4 to 30 components. Very special more preferably, these media contain one or more inventions compounds according to the invention 7 to 25 components. These others Components are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, in particular Substances from the classes of azoxybenzenes, benzylidene anilines, Biphenyls, terphenyls, phenyl or cyclohexyl benzoates, cyclohexane phenyl or cyclohexyl carboxylate, phenyl or cyclohexyl ester cyclohexylbenzoic acid, phenyl or cyclohexyl ester of cyclo hexylcyclohexane carboxylic acid, cyclohexyl phenyl ester of benzoic acid, cyclohexane carboxylic acid or cyclohexylcyclohexane carboxylic acid, Phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, Cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes, 1,4-bis-cyclo hexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, phenyl- or cyclohexyl pyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclohexyl dioxanes, phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethanes, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclohexyl-2- (4- phenyl-cyclohexyl) -ethane, 1-cyclohexyl-2-biphenylylethane, 1-phenyl-2- cyclohexyl-phenylethane, optionally halogenated stilbene, benzyl phenyl ether, tolanes and substituted cinnamic acids. The 1,4-phenylene Groups in these compounds can also be fluorinated.  

The most important compounds which are suitable as further constituents of media according to the invention can be characterized by the formulas 1, 2, 3, 4 and 5:

R'-LER "(1)
R'-L-COO-ER "(2)
R'-L-OOC-ER "(3)
R'-L-CH ₂ CH ₂ -ER "(4)
R'-LC∼CER "(5)

In formulas 1, 2, 3, 4 and 5, L and E mean the same or ver can be different, each independently a bivalent Balance from the from -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr- Dio-, -G-Phe- and -G-Cyc- as well as their mirror images formed group, where Phe is unsubstituted or fluorine-substituted 1,4-phenylene, Cyc trans-1,4-cyclohexylene or 1,4-cyclohexylene, pyr pyrimidine-2-5-diyl or pyridine-2,5-diyl, dio 1,3-dioxane-2,5-diyl and G 2- (trans-1,4-cyclo hexyl) ethyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl mean.

One of the radicals L and E is preferably Cyc, Phe or Pyr. E is in front preferably Cyc, Phe or Phe-Cyc. Preferably contain the inventions media according to the invention selected one or more components the compounds of formulas 1, 2, 3, 4 and 5, wherein L and E are selected are from the group Cyc, Phe and Pyr and simultaneously one or more Components selected from the compounds of the formulas 1, 2, 3, 4 and 5, in which one of the radicals L and E is selected from the group Cyc, Phe and Pyr and the other remainder selected from the group -Phe- Phe-, -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-, and optionally one or more components selected from the compounds of Formulas 1, 2, 3, 4 and 5, in which the radicals L and E are selected from the Group -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-.  

R 'and R "in a smaller subset of the compounds of the Formulas 1, 2, 3, 4 and 5 each independently of the other alkyl, alkenyl, Alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy with up to 8 carbon atoms. This smaller subgroup is called Group A below and the compounds are represented by sub-formulas 1a, 2a, 3a, 4a and 5a designated. For most of these compounds, R 'and R "are the same others different, one of these radicals mostly alkyl, alkenyl, alkoxy or alkoxyalkyl.

In another smaller subgroup, referred to as group B, of the compounds of the formulas 1, 2, 3, 4 and 5, R "means -F, -Cl, -NCS or - (O) _i CH _{3- (k + l)} F _k Cl _l , where i is 0 or 1 and k and l are 1, 2 or 3; the compounds in which R "has this meaning are denoted by sub-formulas 1b, 2b, 3b, 4b and 5b. Those compounds of partial formulas 1b, 2b, 3b, 4b and 5b in which R "has the meaning -F, -Cl, -NCS, -CF ₃ , -OCHF ₂ or -OCF ₃ are particularly preferred.

In the compounds of sub-formulas 1b, 2b, 3b, 4b and 5b, R 'has the at the compounds of the sub-formulas 1a-5a and meaning preferably alkyl, alkenyl, alkoxy or alkoxyalkyl.

In a further smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5 means R "-CN; this subgroup is hereinafter referred to as Group C designated and the compounds of this subgroup described accordingly with sub-formulas 1c, 2c, 3c, 4c and 5c. In the Compounds of the sub-formulas 1c, 2c, 3c, 4c and 5c have R 'those in the Compounds of sub-formulas 1a-5a given meaning and is preferably alkyl, alkoxy or alkenyl.

In addition to the preferred compounds of groups A, B and C are also other compounds of formulas 1, 2, 3, 4 and 5 with other variants of the proposed substituents in use. All of these substances are obtainable according to methods known from the literature or in analogy.  

In addition to the compounds of the formula I according to the invention, the media according to the invention preferably contain one or more compounds which are selected from group A and / or group B and / or group C. The mass fractions of the compounds from these groups in the media according to the invention are preferably:

Group A: 0 to 90%, preferably 20 to 90%, in particular 30 to 90%
Group B: 0 to 80%, preferably 10 to 80%, in particular 10 to 65%
Group C: 0 to 80%, preferably 5 to 80%, in particular 5 to 50%

where the sum of the mass fractions of the invention in each according to media contained compounds from groups A and / or B and / or C preferably 5% -90% and in particular 10% to 90% is.

The media according to the invention preferably contain 1 to 40%, particularly preferably 5 to 30% of the verb according to the invention fertilize. Media containing more than 40% are also preferred. in particular 45 to 90% of compounds according to the invention. The Media preferably contain three, four or five according to the invention Links.

The media according to the invention are produced in a manner which is customary per se Wise. As a rule, the components are dissolved into one another, for this purpose moderate at elevated temperature. With suitable additives, the liquid crystalline phases are modified according to the invention so that it in all types of liquid crystal display that have become known elements can be used. Such additives are the subject known and extensively described in the literature (H. Kelker / R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980).  

For example, pleochroic dyes can be used to produce colored ones Guest host systems or substances for changing the dielectric Anisotropy, the viscosity and / or orientation of the nematic phases be added.

The following examples are intended to illustrate the invention without limiting it. Percentages above and below mean percentages by weight. All temperatures are given in degrees Celsius. Mp. Means melting point Klp. = Clearing point. Furthermore, K = crystalline state, N = nematic phase, Sm = smectic phase and I = isotropic phase. The information between these symbols represents the transition temperatures. Δn means optical anisotropy (589 nm 20 ° C) and Δε the dielectric anisotropy (1 kHz, 20 ° C). The viscosity (mm ² / sec) was determined at 20 ° C.

"Normal work-up" means: if necessary, water is added, extracted with methylene chloride, diethyl ether or toluene, separates, dries the organic phase, evaporates and purifies the product by distillation lation under reduced pressure or crystallization and / or chromato graph.

The following abbreviations are used:

THF: tetrahydrofuran
KOtBu: Potassium tert-butoxide
RT: room temperature
MTB ether: methyl tert-butyl ether

Examples 4-31

Examples 32-59

Examples 60-87

Examples 88-115

Examples 116-126

Examples 127-121

Claims (11)

1. Sulfur pentafluoid derivatives of the formula I.
wherein
H, an unsubstituted, an alkyl radical with 1-12 C atoms or alkenyl radical with 2-12 C atoms which is simply substituted by CN or CF ₃ or an at least monosubstituted by halogen, wherein one or more non-adjacent CH ₂ - Groups each independently
can be replaced
A ¹ and A ²

• a) trans-cyclohexane-1,4-diyl radical, in which one or more non-adjacent CH ₂ groups can also be replaced by -O- and / or -S-,
• b) 1,4-phenylene radical, in which one or two CH groups can also be replaced by N,
• c) residue from the group 1,4-bicyclo (2,2,2) octylene, pipidin-1,4-diyl, naphthalene-2,6-diyl, decahydro naphthalene-2,6-diyl and 1,2 , 3,4-tetrahydronaphthalene-2,6-diyl,
• d) cyclohexane-1,4-diyl, where the radicals a), b) and d) can be substituted by CN, Cl or F,

LH or F,
Z ¹ and Z ² each independently of one another -CO-O-, -O-CO-, -CH ₂ O-, -O-, -O-CH ₂ , -CH ₂ CH ₂ -, -CF ₂ CF ₂ -, -CH = CH-, -C∼C- or a single bond,
and
n and m 0, 1 or 2,
wherein
n + m 0, 1 or 2
means. 2. sulfur pentafluoride derivatives according to claim 1 of formula I, characterized in that R ^{1 is} straight-chain alkyl or alkoxy having 1 to 10 carbon atoms or alkenyl or alkenyloxy having 2-10 carbon atoms. 3. sulfur pentafluoride derivatives according to claim 1 or 2 of formula I, characterized in that A ^{1 has} the meaning
having. 4. sulfur pentafluoride derivatives according to claim 1 to 3, of formula I, characterized in that the radicals Z ¹ and Z ² independently of one another -CH ₂ CH ₂ -, -E-CH = CH-, -C∼C- or one Single bond means. 5. Compounds of the formula IA:
wherein R ¹ , A ¹ , Z ¹ , m and L have the meaning given. 6. Compounds of the formula IB:
wherein R ¹ , A ¹ , Z ¹ , m and L have the meaning given. 7. Use of compounds of formula I, IA and IB after Claims 1 to 6 as components of liquid-crystalline media. 8. Liquid-crystalline medium with at least two liquid-crystalline ones Components, characterized in that there is at least one Contains compound of formula I. 9. Liquid crystal display element, characterized in that it is a contains liquid-crystalline medium according to claim 8. 10. Electro-optical display element, characterized in that it as a dielectric, a liquid-crystalline medium according to claim 8 contains.