DE4325985A1 - Cyanobiphenyls and liquid-crystalline medium - Google Patents

Abstract

Cyanobiphenyls of the formula I, <IMAGE> in which R is an alkyl or alkenyl radical having 1 to 15 carbon atoms which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, where, in these radicals, one or more CH2 groups in each case independently of one another can also be replaced by -O-, -S-, -@-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that O atoms are not directly linked to each other, are suitable as components in liquid-crystalline media.

Description

The invention relates to cyanobiphenyls of the formula I,

wherein
R is an unsubstituted, a simple by CN or CF₃ or at least one halo by substituted alkyl or alkenyl radical having 1 to 15 carbon atoms, wherein in these radicals also one or more CH₂ groups each independently

may be replaced so that O atoms are not directly linked to each other,
means.

The invention further relates to the use of this Ver compounds as components of liquid-crystalline media as well as Liquid crystal and electro-optical display elements, the contain liquid crystalline media according to the invention.

The compounds of the formula I can be liquid as components crystalline media are used, especially for Dis plays based on the principle of the twisted cell, the guest Host effect, the effect of deformation of upright phases or the effect of dynamic dispersion.

The invention was based on the object new stable to find liquid-crystalline or mesogenic compounds which are suitable as components of liquid-crystalline media and especially at the same time a comparatively small Possess viscosity as well as a relatively high dielectric Anisotropy.

It has now been found that compounds of the formula I as Components of liquid-crystalline media excellently suitable are. In particular, they have comparatively low levels Viscosities. With their help can be stable liquid crystalline media with a broad mesophase range and advantageous have values for the optical and dielectric anisotropy receive. These media also have a very good bassiness temperature behavior.  

The compounds of formula I are of the general Formula in WO 87-00078. There are only late Fluorinated cyanobiphenyls are described.

In Mol. Cryst. Liq. Cryst. 1985, Vol. 123, pp. 169-177, Vol. 124, pp. 89-103, Vol. 6 (1989), pp. 515-523 are cyano biphenyls of formulas

called.

Compared to the unfluorinated or monofluorinated cyano biphenylene show the substances according to the invention, a much less tendency to smectic Phases on.

With regard to the most diverse fields of application suchi However, it was desirable for compounds with a high Δε Other compounds with high nematogeneity available have tailor-made to the respective applications have distinctive properties.

With the provision of compounds of the formula I is also quite generally the range of liquid crystalline Substances that vary in their application aspects of the production of liquid crystalline Mixtures are suitable, considerably widened.  

The compounds of the formula I have a broad application dung area. Depending on the choice of Substi These compounds can be used as base materials from which liquid-crystalline media predominantly Part are composed; but it can also connections of formula I liquid-crystalline base materials from others Added classes of compounds, for example, the dielectric and / or optical anisotropy of such Dielectric affect and / or its thresholds to optimize voltage and / or its viscosity.

The compounds of the formula I are colorless in the pure state and form liquid crystalline mesophases in one for the Electro-optical use conveniently located temperature Area. Chemically, thermally and against light, they are stable.

The invention thus relates to the compounds of Formula I and the use of these compounds as a compo nenten liquid-crystalline media. Subject of the invention are also liquid crystalline media containing at least one compound of the formula I and Flüssigkri stall display elements, in particular electro-optical display elements containing such media.

In the compounds of the formula I, R is preferably Alkoxy, further alkyl.  

If R is an alkyl radical and / or an alkoxy radical, this may be straight-chain or branched. Preferably if it is straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and therefore preferably denotes ethyl, propyl, butyl, pentyl, Hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or Heptoxy, furthermore methyl, octyl, nonyl, decyl, undecyl, Dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, Nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetra decoxy.

Oxaalkyl is preferably straight-chain 2-oxapropyl (= Methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxo-octyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R is an alkyl radical in which a CH₂ group is replaced by -CH = CH-, so this can be straight or be branched. Preferably, it is straight-chain and has 2 to 10 C atoms. He 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.  

If R is an alkyl radical in which a CH₂ group replaced by -O- and one by -CO-, these are preferably adjacent. Thus, these include an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. virtue wise, these are straight-chain and have 2 to 6 carbon atoms.

They therefore mean especially acetyloxy, propionyloxy, Butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, Propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, Methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxy carbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxy carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxycarbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxycarbonyl) -butyl.

If R is an alkyl radical in which a CH₂ group by unsubstituted or substituted -CH = CH- and a adjacent CH₂ group replaced by CO or CO-O or O-CO is, it may be straight or branched. virtue It is straight-chain and has 4 to 13 carbon atoms. He means tetra especially acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxy-heptyl, 8-acryloyloxy octyl, 9-acryloyloxynonyl, 10-acryloyloxydecyl, methacryl oyloxymethyl, 2-methacryloyloxyethyl, 3-methacryloyloxy propyl, 4-methacryloyloxy-butyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryl oyloxyoctyl, 9-methacryloyloxynonyl.  

If R is an alkyl substituted by CN or CF₃, or alkenyl radical, this radical is preferably straight-chain and the substitution by CN or CF₃ in ω-Posi tion.

If R is at least one halogen substituted Alkyl or alkenyl radical, then this radical is preferred Were straight-chain and halogen is preferably F or Cl. at Multiple substitution is halogen preferably F. The resul ting residues also include perfluorinated residues. at Simple substitution can be the fluorine or chlorine substituent in be any position, but preferably in the ω position.

Compounds of the formula I which are above for polymerization Reactions suitable wing groups R are suitable for the preparation of liquid-crystalline polymers.

Compounds of the formula I with branched wing groups R occasionally because of better solubility in the Of conventional liquid-crystalline base materials of importance but especially as chiral dopants, if they are are optically active. Smectic compounds of this kind eig as components for ferroelectric materials.

Compounds of the formula I with S _A phases are suitable for example for thermally addressed displays.

Branched groups of this type usually do not contain more than one chain branch. Preferred branched radicals R is isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methyl butyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethyl hexoxy, 1-methylhexoxy, 1-methylheptoxy.

If R represents an alkyl radical in which two or more CH₂ groups are replaced by -O- and / or -CO-O-, so can this be straight-chain or branched. Preferably, he is branched and has 3 to 12 carbon atoms. He means accordingly especially bis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3- Bis-carboxy-propyl, 4,4-bis-carboxy-butyl, 5,5-bis-carboxy pentyl, 6,6-bis-carboxyhexyl, 7,7-bis-carboxyheptyl, 8,8- Bis-carboxy-octyl, 9,9-bis-carboxy-nonyl, 10,10-bis-carboxy decyl, bis (methoxycarbonyl) methyl, 2,2-bis (methoxycar ethyl), 3,3-bis- (methoxycarbonyl) -propyl, 4,4-bis- (methoxycarbonyl) -butyl, 5,5-bis (methoxycarbonyl) -pentyl, 6,6-Bis (methoxycarbonyl) hexyl, 7,7-bis (methoxycarbonyl) heptyl, 8,8-bis (methoxycarbonyl) octyl, bis (ethoxycar ethyl), 2,2-bis- (ethoxycarbonyl) -ethyl, 3,3-bis- (ethoxycarbonyl) -propyl, 4,4-bis (ethoxycarbonyl) -butyl, 5,5-bis- (ethoxycarbonyl) -hexyl.

Compounds of the formula I which are more than suitable for polycondensations suitable wing groups R are suitable for presentation development of liquid crystalline polycondensates.  

Formula I includes both the racemates of these compounds as also the optical antipodes and their mixtures.

Among these compounds of the formula I and the sub Formulas are those in which at least one the radicals contained therein one of the specified preferred Has meanings.

The compounds of the formula I are known per se Methods presented in the literature (eg in the Standard works such as Houben-Weyl, Methods of the Organic Chemistry, Georg Thieme Verlag, Stuttgart) are described, under reaction conditions, for the mentioned Reactions are known and suitable.

It is also known by itself, not closer make use of the variants mentioned.

The compounds of the invention may, for. B. as follows getting produced:

Scheme 1

The synthesis of some particularly preferred compounds is specified in the following:

Scheme 2

The liquid-crystalline media according to the invention contain preferably in addition to one or more inventive Compounds as further constituents 2 to 40, in particular 4 to 30 components. Very particularly preferably included these media in addition to one or more inventive Compounds 7 to 25 components. This further inventory Parts are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, esp substances from the classes of azoxybenzenes, benzylidene anilines, biphenyls, terphenyls, phenyl- or cyclohexylbenes zoates, cyclohexane-carboxylic acid phenyl or cyclohexyl esters, Phenyl or cyclohexyl esters of cyclohexylbenzoic acid, Phenyl or cyclohexyl esters of Cyclohexylcyclohexancar bonsäure, Cyclohexyl-phenylester of benzoic acid, the cyclo hexanecarboxylic acid or cyclohexylcyclohexanecarboxylic acid,  Phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcy clohexane, cyclohexylcyclohexane, cyclohexylcyclohexylcyclo hexanes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclohexyl biphenyls, phenyl or cyclohexylpyrimidines, phenyl or Cyclohexylpyridines, phenyl- or cyclohexyl-dioxanes, phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicy clohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclo hexyl 2- (4-phenyl-cyclohexyl) -ethanes, 1-cyclohexyl-2-biphenyl 1-phenyl-2-cyclohexyl-phenylethanes, optionally halogenated stilbenes, benzylphenyl ethers, tolans and substi tanned cinnamic acids. The 1,4-phenylene groups in these Ver bonds can also be fluorinated.

The most important as further constituents according to the invention Media eligible connections can be through the Formulas 1, 2, 3, 4 and 5 characterize:

R'-L-E-R '' 1 R'-L-COO-E-R '' 2 R'-L-OOC-E-R '' 3 R'-L-CH₂CH₂-E-R '' 4 R'-L-C≡C-E-R '' 5

In formulas 1, 2, 3, 4 and 5, L and E are the same or may be different, each independently a bivalent radical from the group consisting of -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc, -Cyc-Cyc, -Pyr-, -Dio, -G-Phe- and -G-Cyc- and their mirror images formed group, where Phe unsubstitu  substituted or fluorine-substituted 1,4-phenylene, Cyc trans-1,4-cyclohexylene or 1,4-cyclohexylene, Pyr pyrimi din-2-5-diyl or pyridine-2,5-diyl, Bio 1,3-dioxane-2,5-diyl and G 2- (trans-1,4-cyclohexyl) -ethyl, pyrimidine-2,5-diyl, Pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl.

Preferably, one of L and E is Cyc, Phe or Pyr. e is preferably Cyc, Phe or Phe-Cyc. Preferably ent the media of the invention one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein L and E are selected from the group Cyc, Phe and Pyr and at the same time one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein one of L and E is selected from the group Cyc, Phe and Pyr and the other radical is 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 the formulas 1, 2, 3, 4 and 5, wherein 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 subgroup denote the verb of the formulas 1, 2, 3, 4 and 5 are each independent of alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or Alkanoyloxy with up to 8 carbon atoms. The following will be this smaller subgroup called group A and the verbin tions are with the sub-formulas 1a, 2a, 3a, 4a and 5a designated. For most of these compounds, R 'and R '' different from each other, with one of these radicals usually Alkyl, alkenyl, alkoxy or alkoxyalkyl.  

In a smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5 designated as group B, R '' is -F, -Cl, -NCS or - (O) _i - CH ₃ - _{(k + 1)} F _l Cl₁, where i is 0 or 1 and k + 1 is 1, 2 or 3; the compounds in which R "has this meaning are designated by the subformulae 1b, 2b, 3b, 4b and 5b. Particular preference is given to those compounds of sub-formulas 1b, 2b, 3b, 4b and 5b in which R "has the meaning -F, -Cl, -NCS, -CF₃, -OCHF₂ or -OCF₃.

In the compounds of sub-formulas 1b, 2b, 3b, 4b and 5b has R 'indicated in the compounds of the sub-formulas 1a-5a Meaning and is preferably alkyl, alkenyl, alkoxy or Alkoxyalkyl.

In another smaller subgroup of compounds of Formulas 1, 2, 3, 4 and 5 are R "-CN; this subgroup is hereinafter referred to as group C and the Verbindun of this subgroup are correspondingly subformulated 1c, 2c, 3c, 4c and 5c. In the compounds of Partial formulas 1c, 2c, 3c, 4c and 5c has R 'in the verbin of the 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 ge bräuchlich. All these substances are known from the literature methods or by analogy.  

The media of the invention contain in addition fiction compounds of the formula I preferably one or several compounds which are selected from the group A and / or group B and / or group C. The mass fractions of Compounds from these groups on the inventive Media are preferred

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

where the sum of the mass fractions in the respective Compounds of the invention contained in the Groups A and / or B and / or C preferably 5 to 90% and especially 10 to 90%.

The media according to the invention preferably contain 1 to 40%, in particular preferably 5 to 30% of erfindungs proper connections. Further preferred are media, ent holding more than 40%, in particular 45 to 90% of inventions compounds according to the invention. The media preferably contain three, four or five compounds of the invention.  

The preparation of the media according to the invention takes place in usual way. In general, the components are dissolved in each other, useful at elevated temperature. By Suitable additives can after the liquid crystalline phases of the invention are modified so that they are in all hitherto have become known types of liquid crystal display elements can be used. Such additives are those skilled in the art known and described in detail in the literature (H.Kalkker / R.Hatz, Handbook of Liquid Crystals, Verlag Chemistry, Weinheim, 1980). For example, pleochroiti dyestuffs for producing colored guest-host systems or substances for changing the dielectric anisotropy pie, the viscosity and / or the orientation of the nematic Phases are added.

In the present application and in the following examples, the structures of the liquid crystal compounds are indicated by acronyms, wherein the transformation into chemical formulas according to following Tables A and B takes place. All radicals C _n H _{2n + 1} and C _m H _{2m + 1} are straight-chain alkyl radicals with n or m C atoms. The coding according to Table B is self-evident. In Table A, only the acronym for the main body is given. In the individual case, a code for the substituents R 1, R 2, L 1 and L 2 follows separately from the acronym for the main body with a dash:

Table A

Table B

The following examples are intended to illustrate the invention, without to limit them. Above and below mean percentanga ben weight percent. All temperatures are in degrees Celsius specified. Mp means melting point, bp = clearing point. Further K = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The information between these symbols represent the transition temperatures Δn means optical anisotropy (589 nm, 20 ° C) and the Viscosity (mm² / sec) was determined at 20 ° C.

"Usual work-up" means: one gives if necessary Add water, extracted with dichloromethane, diethyl ether or Toluene, separates, the organic phase is dried, evaporated and purifies the product by distillation under reduced pressure Pressure or crystallization and / or chromatography. The following Abbreviations are used:

DMEU 1,3-dimethyl-2-imidazoldinon KOT Potassium tert-butoxide THF tetrahydrofuran pTSOH p-toluenesulfonic acid

example 1

0.3 mol of 4-bromo-2-fluorobenzonitrile are added with 0.33 mol 2-fluoro-4-methoxybenzene boronic acid, 77 ml of toluene, 350 ml Ethanol, 490 ml of 2 molar sodium carbonate solution and 9.1 g of tetrakis (triphenylphosphine) palladium and Boiled under reflux for 3.5 h. Subsequently, like worked up usual. Last, the product is off Recrystallized ethanol. K 123 I.

0.14 mol of 2,3'-difluoro-4'-methoxy-4-cyanobiphenyl in 350 ml of xylene and 0.21 mol of aluminum chloride and heated to 100 ° C for 3 h. Subsequently, as usual worked up.

13 mmol of 2,3'-difluoro-4'-hydroxy-4-cyanobiphenyl, 15 mmol Iodobutane and 15 mmol of potassium carbonate are dissolved in 70 ml Dissolved methyl ethyl ketone and boiled under reflux for 3 h. You work up as usual and crystallize that Product in methanol. K 41 I; Δn = + 0.191; Δε = 33, 94.  

Analogously, the following compounds are prepared:

Examples mix

Example A P15-3 | 22% ME2N.F 3% ME3N.F 3% B-30.FN.F 6% B-40.FN.F 5% P20-302 15% CCH-34 3% ECCP 3F.F 4% ECCP 5F.F 4% CCP 2OCF₃ 4% C²⁵-3OCF₃ 4% CCP 4OCF₃ 4% CPTP-301 5% CPTP-302 5% ECCP 31 4% ECCP 32 4% ECCP 33 3% CCPC-33 2%

Example B PCH-3 | 22% ME2N.F 3% ME3N.F 3% B30.FN.F 7% B40.FN.F 7% PCH-302 8th% CCH-34 10% CCP 2OCF₃ 7% CCP 3OCF₃ 7% CCP 4OCF₃ 6% CPTP-301 5% CPTP-302 5% ECCP 31 4% ECCP 32 4% CCPC-33 2%

Example C PCH-3 | 22% ME2N.F 3% ME3N.F 3% B30.FN.F 6% B40.FN.F 6% PCH-302 13% ECCP 3F.F 4% ECCP 5F.F 4% CCP 2OCF₃ 7% CCP 3OCF₃ 7% CCP 4OCF₃ 6%   CPTP-301 4% CPTP-302 5% ECCP 31 4% ECCP 32 4% CCPC-33 2%

Claims (6)

1. Cyanobiphenyls of the formula I, wherein
R is an unsubstituted, a simple by CN or CF₃ or at least one halogen-substituted alkyl or alkenyl radical having 1 to 15 carbon atoms, wherein in these radicals also one or more CH₂ groups each independently may be replaced so that O atoms are not directly linked to each other,
means. 2. Compounds of the formula 3. Use of compounds of the formula I as a component th liquid-crystalline media. 4. Liquid-crystalline medium with at least two liquids crystalline components, characterized in that it contains at least one compound of formula I. 5. Liquid crystal display element, characterized in that it is a liquid-crystalline medium according to claim 4 contains. 6. Electro-optical display element, characterized gekennzeich net, that it is a liquid crystalline as a dielectric Medium according to claim 4 contains.