DE4441963A1 - Alkenyl-cyclohexane(s) useful in liquid crystal medium for display - Google Patents

Abstract

Alkenyl-cyclohexane derivs. of formula (I) are new : R1-CH=CH-(CH2)n-(Cyc)m-CH=CH-Cyc'-(A)r-R2 (I);In (I), Cyc = trans-1,4-cyclohexylene; Cyc' = 1,4-cyclohexylene; R1 = H or 1-5C alkyl; R2 = 1-10C alk(en)yl, opt. mono-substd. by CN or CF3 or at least mono-substd. by halogen, in which 1 or more CH2 gps. may be replaced by -O- or -CO- without directly linked O atoms; CN; F; Cl; OCN; or NCS; A = Cyc, 1,4-phenylene (Phe) or 2- or 3-fluoro- or 2,6-difluoro-1,4-phenylene; m = 1 or 2; n = 0-6; r = 0 or 1. Also claimed is a liquid crystal (LC) medium contg. cpd(s). (I).

Description

The invention relates to cyclohexane derivatives of the formula I.

in which
R¹ is H or alkyl of 1 to 5
R 2 is an unsubstituted or substituted by CN or CF₂ or at least one halogen-substituted alkyl or alkenyl radical having 1 to 10 carbon atoms, in which radical one or more CH₂ groups replaced by -O- or -CO- so may be that O atoms are not directly linked, CN, F, Cl, OCN, NCS,

m 1 or 2
n 0 to 6, and
r 0 or 1
mean.

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 comprising the liquid-crystalline Media included.

The compounds of the formula I can be used as components of liquid-crystalline Media are used, especially for displays based on the principle the twisted cell, the guest-host effect, the effect of deformation upright phases or the effect of dynamic dispersion rest.

The invention was based on the object new stable liquid crystalline or to find mesogenic compounds that are liquid as components crystalline media are suitable and in particular at the same time a ver have low viscosity and a relatively high Nemato geneity.

With regard to the most diverse fields of application of such verbin However, with low Δε, it was desirable to have other compounds high nematogeneity available on the specific applications to exactly tailor-made properties point. With the help of the compounds of the invention can be Realize STN mixtures with surprisingly good slope. Compared to the corresponding saturated compounds have this sub punch higher clearing points, better solubility, as well as a key Lich less tendency to form smectic phases.

Similar compounds are described in EP 0 256 097 B1, these However, in contrast to the compounds of the invention an alkenyloxy group instead of an alkenyl group.

It has now been found that compounds of the formula I as components liquid-crystalline media are eminently suitable. In particular They have comparatively low viscosities. With their help can be  stable liquid-crystalline media with broad nematic mesophases range and favorable values for the optical and dielectric aniso received tropie. These media also have a very good low temp on behavior.

With the provision of compounds of formula I is also completely In general, the range of liquid-crystalline substances that are under various application-technical aspects for the production liquid-crystalline mixtures, significantly widened.

The compounds of the formula I have a broad application Area. Depending on the choice of substituents, these may Compounds serve as base materials from which liquid crystalline Media are composed for the most part; but it can also compounds of formula I liquid-crystalline base materials be added to other classes of compounds, for example, the dielectric and / or optical anisotropy of such a dielectric affect and / or the threshold voltage and / or its To 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 they are stable against light.

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

Some very particularly preferred smaller group of compounds are those of the subformulae I1 and I6 (L: H or F, R ^{2 '} = alkyl):

R¹ in sub-formulas I1 to I6 is preferably H or methyl. R 2 is preferably alkyl, alkenyl, alkoxy, CN or a halogenated alkyl or alkenyl radical. Halogen is preferably F. R² is in particular, F, Cl, OCF₃, OCF₂H₁ CF₃, OCH₂CF₃, OCHFCF₃, OC₂F₅, C₂F₅, OC₂F₄H, OCHF₂, CH = CH₂ or CH = CH-CH₃. R ^{2 '} is H or alkyl of 1 to 5 carbon atoms, preferably H or methyl. o is 0 to 6.

If R 2 is an alkyl radical and / or an alkoxy radical, then this be straight-chain or branched. Preferably, 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, methoxy, octoxy, Nonoxy or decoxy.

Oxaalkyl is preferably 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-oxo-octyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxa nonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R² is an alkyl radical in which a CH₂ group is replaced by -CH = CH- is replaced, it may be straight-chain or branched. Preferably it is straight-chain and has 2 to 10 carbon atoms. He means accordingly 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 octyl- 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 R² is an alkyl radical in which a CH₂ group by -O- and one replaced by -CO-, these are preferably adjacent. Thus These include an acyloxy group -CO-O- or an oxycarbo nyl group -O-CO-. Preferably, these are straight-chain and have 2 to 6 C-atoms.

They therefore 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, ethoxycar bonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxy carbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxycarbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxy carbonyl) -butyl.  

If R² is an alkyl radical in which a CH₂ group by unsub substituted or substituted -CH = CH- and an adjacent CH₂ group replaced by CO or CO-O or O-CO, this can be straight-chain or be branched. Preferably, it is straight-chain and has 4 to 13 C atoms. He therefore means especially acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryl oyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxyheptyl, 8-acryloyloxyoctyl, 9-acryloyloxynonyl, 10-acryloyloxydecyl, methacryloyloxymethyl, 2-methacryloyloxyethyl, 3-methacryloyloxypropyl, 4-methacryloyloxybutyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoctyl, 9-methacryloyloxynonyl.

If R² is an alkyl radical substituted by CN or CF₃ Alkenyl means, this radical is preferably straight-chain and the Substitution by CN or CF₃ in the ω position.

If R² is an alkyl or at least monosubstituted by halogen Alkenyl radical, this radical is preferably straight-chain and Halogen is preferably F or Cl. When multiple substitution is halogen preferably F. The resulting radicals also include perfluorinated Leftovers. For single substitution, the fluorine or chlorine substituent may be in be any position, but preferably in the ω position.

Compounds of the formula I with branched wing groups R¹ and R² can occasionally because of a better solubility in the usual liquid-crystalline base materials, in particular but as chiral dopants when they are optically active.

Branched groups of this type usually contain no more than one Chain branching. Preferred branched radicals 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-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 1-methylheptoxy.  

If R² represents an alkyl radical in which two or more CH₂ groups replaced by -O- and / or -CO-O-, it may be straight-chain or be branched. Preferably, it is branched and has 3 to 12 carbon atoms. He therefore particularly denotes bis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl, 4,4-bis-carboxy-butyl, 5,5-bis-carboxypentyl, 6,6-bis-carboxy-hexyl, 7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl, 10,10-bis-carboxy-decyl, Bis (methoxycarbonyl) methyl, 2,2-bis (methoxycarbonyl) 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 (ethoxycarbonyl) methyl, 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 suitable for polycondensations Have wing groups R¹ and R² are suitable for illustration liquid crystalline polycondensates.

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

Among these compounds of formula I and the sub-formulas are those in which at least one of them contains Rests has one of the preferred meanings given.

In the compounds of formula I, those stereoisomers are forthcoming zugt, in which the rings are trans-1,4-disubstituted cyclohexane rings.

The compounds of the formula I are prepared by methods known per se as described in the literature (eg in the standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart), under reaction conditions suitable for the said reactions are known and suitable.  

One can also of known per se, not mentioned here Make use of variants.

The compounds of the invention may, for. B. prepared as follows become:

Scheme 1

Scheme 2

The liquid-crystalline media of the invention preferably contain in addition to one or more compounds according to the invention as further Ingredients 2 to 40, in particular 4 to 30 components. Very special These preferably contain these media in addition to one or more inventions compounds according to the invention 7 to 25 components. These others Ingredients are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, in particular Substances from the classes of the azoxybenzenes, Benzylidenaniline, Biphenyls, terphenyls, phenyl or cyclohexyl benzoates, cyclohexane carboxylic acid-phenyl or cyclohexyl esters, phenyl or cyclohexyl esters the cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexyl Cyclohexanecarboxylic acid, Cyclohexylphenylester of benzoic acid, the Cyclohexanecarboxylic acid or cyclohexylcyclohexanecarboxylic acid, Phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, Cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes, 1,4-biscyclo hexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, phenyl or cyclohexyl pyrimidines, phenyl or cyclohexylpyridines, phenyl or cyclohexyl dioxanes, phenyl or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclohexyl 2- (4-phenylcyclohexyl) ethanes, 1-cyclohexyl-2-biphenylylethanes, 1-phenyl-2-cyclohexyl-phenylethane, optionally halogenated Stilbenes, benzylphenyl ethers, tolans and substituted cinnamic acids. The 1,4-phenylene groups in these compounds may also be fluorinated.

The most important as further constituents of inventive media in Questioning compounds can be represented by the formulas 1, 2, 3, 4 and 5 characterize:

R'-LER '' 1
R'-L-COO-ER '' 2
R'-L-OOC-ER "3
R'-L-CH₂CH₂-ER "4
R'-LC = C≡ER '' 5.

In the formulas 1, 2, 3, 4 and 5, L and E denote the same or ver can be separate, each independently a bivalent The residue of -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr-, -Dio, -G-Phe and -G-Cyc and their mirror images formed group, where Phe is unsubstituted or fluorine-substituted 1,4-phenylene, Cyctrans-1,4-cyclohexylene or 1,4-cyclohexylene, Pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl, bio-1,3-dioxane-2,5-diyl and G 2- (trans-1,4-cycloo hexyl) -ethyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl mean.

Preferably, one of L and E is Cyc, Phe or Pyr. E is present preferably Cyc, Phe or Phe-Cyc. Preferably, the inventions contain According to the media one or more components selected from 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 at the same time one or more Components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein one of the radicals L and E is selected from the group Cyc, Phe and Pyr and the other rest 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 of the compounds mean Formulas 1, 2, 3, 4 and 5 are each independently alkyl, alkenyl, Alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy of up to 8 carbons atoms. The following is this smaller subgroup Group A and the compounds are identified by the subforms 1a, 2a, 3a, 4a and 5a. For most of these compounds, R 'and R' 'are different from one another, wherein one of these radicals is usually alkyl, alkenyl, Alkoxy or alkoxyalkyl is.  

In a smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5 designated as group B, R ", -F, -Cl, -NCS or - (O) _i denotes CH _{3 (k + 1)} F _k 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 sub-formulas 1b, 2b, 3b, 4b and 5b. Particular preference is given to those compounds of the subformulae 1 b, 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 R 'has the at the meaning of the compounds of sub-formulas 1a-5a and is preferably alkyl, alkenyl, alkoxy or alkoxyalkyl.

In a further smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5 is R ", -CN; this subgroup is hereafter referred to as Group C and become the compounds of this subgroup according to sub-formulas 1c, 2c, 3c, 4c and 5c described. In the Compounds of sub-formulas 1c, 2c, 3c, 4c and 5c have R 'in the Compounds of the subformulae 1a-5a given meaning and is present 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 the proposed substituents in use. All these substances are by literature methods or in analogy available.

In addition to 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 on 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%
wherein the sum of the mass fractions of the compounds of the groups A and / or B and / or C contained in the respective inventive media is preferably 5 to 90% and in particular 10 to 90%.

The inventive media preferably contain 1 to 40%, esp especially preferably 5 to 30% of compounds of the invention. Further preferred are media containing more than 40%, in particular 45 to 90% of compounds of the invention. The media included preferably three, four or five compounds according to the invention.

The preparation of the media according to the invention takes place in per se Wise. In general, the components are dissolved in each other, purpose moderately at elevated temperature. By suitable additives, the liquid crystalline phases according to the invention are modified so that they are in all hitherto known types of liquid crystal display elements can be used. Such additives are the subject known and described in detail in the literature (H. Kelker / R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980). For example, pleochroic dyes for producing colored Guest host systems or substances for changing the dielectric Anisotropy, viscosity and / or 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 the following Tabel len 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 basic 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 being limits. Above and below are percentages by weight percent. All temperatures are in degrees Celsius. Mp means Melting point, bp. = Clearing point. Furthermore, K = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The Indications between these symbols represent the transition temperatures Δn means optical anisotropy (589 nm, 20 ° C) and viscosity (mm² / sec) was determined at 20 ° C.

"Usual workup" means: if necessary, add water, extracted with dichloromethane, diethyl ether, methyl tert. Butyl ether or Toluene, separated, the organic phase is dried, evaporated and purified the product by distillation under reduced pressure or crystallization and / or chromatography.

The following abbreviations are used:

DMF N, N-dimethylformamide DMEU 1,3-dimethyl-2-imidazolidinone KOT Potassium tert-butoxide THF tetrahydrofuran pTsOH p-toluenesulfonic acid

Example 1

In a nitrogen atmosphere 2.93 ml Methoxymethyltrimethyltri phenylphosphonium chloride and 2.93 moles of 4-cyclohexanonecarboxylic acid dissolved in 4 l of THF and at room temperature with stirring with 2.93 mol Kaliumtert.butylat added. It is stirred for 2 h, mixed with water and verd. Hydrochloric acid and works up as usual.

50.4 mmol II, 1.0 g 10% HCl, 20 ml THF and 50.4 mmol acetaldehyde are stirred for 0.75 h at room temperature. It is mixed with water and Methyl tert-butyl ether and works up as usual.

In a nitrogen atmosphere 46.1 mmol of potassium tert.butylat in 20 ml of THF to 46.1 mmol of methyltriphenylphosphonium bromide dissolved in 50 ml THF is added dropwise at 0 ° C. After stirring for 10 minutes, 46.1 mmol III are dissolved in 20 ml of THF was added dropwise to the solution. It is allowed to reach room temperature Heat, mixed with water and dil. HCl and methyl tert-butyl ether and works up as usual.

65.8 mmol of Vitride be submitted at 0 ° C in 35 ml of toluene and under Stirred with 72.3 mmol of morpholine dissolved in 20 ml of toluene. The Solution is added dropwise at -40 ° C to 32.9 mmol IV dissolved in 30 ml of toluene  and stirred at -40 to -50 ° for 70 min. It is mixed at -40 ° C with water and at -10 ° C with 10% HCl. Subsequently, as usual worked up.

0.04 mol of V, 0.04 mol of 4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl methyltriphenylphosphonium iodide and 1140 ml of THF are introduced and mixed in portions with 0.40 mol of potassium tert.butylat, wherein the reac tion temperature 35 ° C should not exceed. It is stirred overnight at room temperature, hydrolyzed, mixed with dil. HCl and worked up as usual. K -2 S _B 188 N 222.2 I; Δn = +0.888; Δε = 1.03
Analogously, the following compounds of the formula

manufactured:

Claims (12)

1. cyclohexane derivatives of the formula I, in which
R 1 is H or alkyl having 1 to 5 C atoms,
R 2 is an unsubstituted or substituted by CN or CF₂ or at least one halogen-substituted alkyl or alkenyl radical having 1 to 10 carbon atoms, in which radical one or more CH₂ groups replaced by -O- or -CO- so may be that O atoms are not directly linked, CN, F, Cl, OCN, NCS, m 1 or 2
n 0 to 6, and
r 0 or 1
mean. 2. Compounds of the formula I1 wherein R¹, R² and n have the meaning given in claim 1. 3. Compounds of the formula I2, wherein R¹ and n have the meaning given in claim 1 and R ^{2 'is} H or alkyl having 1 to 5 carbon atoms and o is 0 to 6. 4. Compounds of the formula I3, wherein R¹, R² and n have the meaning given in claim 1. 5. Compounds of the formula I4, wherein R¹, R² and n have the meaning given in claim 1. 6. Compounds of the formula I5, wherein R¹, R² and n have the meaning given in claim 1. 7. Compounds of the formula I6, wherein R¹, R² and n have the meaning given in claim 1. 8. Compounds according to claim 1, wherein R² is F, Cl, CN, OCHFCF₃, OCF₃, OCF₂H, alkyl, alkenyl or alkoxy. 9. Use of compounds of the formula I as components liquid-crystalline media.   10. Liquid-crystalline medium with at least two liquid-crystalline Components, characterized in that they have at least one Contains compound of formula I. 11. Liquid crystal display element, characterized in that it is a Liquid-crystalline medium according to claim 8 contains. 12. Electro-optical display element, characterized in that it as dielectric a liquid-crystalline medium according to claim 8 contains.