DE4314085A1 - Benzene derivatives, and liquid-crystalline medium - Google Patents

Abstract

Benzene derivatives of the formula I, <IMAGE> in which R, A<1>, A<2>, Z<1>, Z<2>, L<1>, L<2> and m as found in Claim 1, are suitable as components of liquid-crystalline media.

Description

The invention relates to benzene derivatives of the formula I

wherein
R QY where
Q -O-, -S- or single bond
Y mono- or polyhalogenated alkyl or alkenyl with 2-12 C atoms
is
A¹ trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH₂ groups can also be replaced by -O- and / or -S-,
A² (a) an unsubstituted or single or multiple fluorinated 1,4-phenylene radical
(B) trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH₂ groups can be replaced by -O- and / or -S-
(c) residue from the group 1,4-cyclohexylene, 1,4-bicyclo [2.2.2] octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1 , 2,3,4-tetrahydronaphtahlin-2,6-diyl,
Z¹ and Z² each independently of one another -CO-O-, -O-CO-, -CO-O-, -O-CO-, -CH₂O-, -OCH₂-, -CH₂CH₂-, -CH = CH-, C≡ C-, - (CH₂) ₄- or -CH = CH- CH₂CH₂- or a single bond,
L¹ and L² are each independently H or F, and
m 0, 1 or 2
means.

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

The compounds of 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 the deformation of aligned phases or based on the effect of dynamic scattering.  

The invention was based, new stable task to find liquid-crystalline or mesogenic compounds, which are suitable as components of liquid-crystalline media and in particular at the same time a comparatively small one Have viscosity and a relatively high dielectric Anisotropy.

It has now been found that compounds of the formula I as Components of liquid crystalline media are particularly suitable are. In particular, they are comparatively low viscosities. With their help, stable liquid crystalline media with a wide mesophase range and advantageous values for the optical and dielectric Preserved anisotropy. These media also show a lot good low-temperature behavior.

Compounds with liquid crystalline properties that Containing fluorinated side chains are known.

Similar halogen-containing compounds via their liquid crystalline properties no statements made are described in EP 0 452 719.

DE 41 13 309 describes compounds of the formula

described.

DE 40 34 508 discloses compounds of the type

known.

In EP-OS 03 30 216 compounds of the formula

called.  

However, the latter compounds show relatively high values for the viscosity. Liquid crystal mixtures that this compound contains still have relatively small values for electrical resistance and are for different applications less suitable.

With regard to the most diverse areas of application such However, with high Δn compounds, it was desirable to have other connections available on the precisely tailored properties for each application exhibit.

With the provision of compounds of formula I will also generally the range of liquid crystalline Substances that are under different application techni viewpoints for the production of liquid crystalline Mixtures are suitable, considerably widened.

The compounds of formula I have a wide range of uses area of application. Depending on the choice of Substi These compounds can be used as base materials serve from which liquid-crystalline media predominate the part is composed; but it can also connect gene of formula I from liquid crystalline base materials other classes of compounds can be added, for example the dielectric and / or optical anisotropy to influence such dielectric and / or in order to To optimize threshold voltage and / or its viscosity.  

The compounds of the invention are notable for their low 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 of conveniently located Temperaturbe rich. They are stable chemically, thermally and against light.

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 Invention are also liquid crystalline media with a Content of at least one compound of the formula I and Liquid crystal display elements, especially electro-optical ones Display elements that contain such media.

For the sake of simplicity, mean below

Dio a 1,3-dioxane-2,5-diyl residue, Dit a 1,3-dithiane-2,5- diyl radical, Phe a 1,4-phenylene radical, Pyd a pyridine-2,5- diyl radical and Pyr a pyrimidine-2,5-diyl radical, Cyc and / or Phe unsubstituted or single or double by F or CN can be substituted.

A² is preferably selected from the group Cyc, Phe, Pyr, Pyd and Dio. Preferably only one is present in the molecule existing residues A¹ and A², a heteroryclic ring.  

The compounds of the formula I accordingly comprise Ver bindings with two rings of sub-formulas Ia and Ib:

R-A¹-A³-Y (Ia)
R-A¹-Z²-A³-Y (Ib)

as well as compounds with three rings of partial formulas Ic to Ie:

R-A¹-A²-A³-Y (Ic)
R-A¹-Z¹-A²-A³-Y (Id)
R-A¹-A²-Z³-A³-Y (Ie)

as well as connections with four rings of the sub-formulas If to Ij:

R-A¹-A²-A²-A³-Y (If)
R-A¹-Z¹-A²-A²-A³-Y (Ig)
R-A¹-Z¹-A²-Z³-A²-A³-Y (Ih)
R-A¹-A¹-A²-Z³-A³-Y (Ii)
R-A¹-Z¹-A²-A²-Z³-A³-Y (Ij)

These include in particular those of sub-formula Ia, Ic, Id and Ie preferred.

Compounds of the formula I and all are also preferred Sub-formulas in which A² and / or A³ through once or twice F or 1,4-phenylene substituted simply by CN. In particular, these are 2-fluoro-1,4-phenylene, 3-fluoro-1,4- phenylene and 3,5-difluoro-1,4-phenylene and 2-cyano-1,4-pheny len and 3-cyan-1,4-phenylene. In a particularly preferred The embodiment is A³ 3,5-difluoro-1,4-phenylene and m 1 or 2.  

One of Z¹ and Z³ is preferably a single bin dung, -CO-O-, -O-CO- and -CH₂CH₂-, preferred in the second place -CH₂O- and -OCH₂-, while the other Z¹ or Z² one Single bond is.

Particularly preferred connections correspond to the subfor meln IIa to IId. (L¹, L²: H or F):

If R is a halogenated alkyl, alkoxy or alkenyl radical mean, this can be straight-chain or branched. It is preferably straight-chain and has 2, 3, 4, 5, 6 or 7 Carbon atoms; in the case of the alkenyl radical 2, 3, 4, 5, 6 or 7 C atoms.  

R is preferably (CH₂) _n -CH = CF₂, (CH₂) _n -CH = CHF, (CH₂) _n -CH = CCl₂, (CF₂) _n -CF₂H, (CH₂) _n -CF₃, (CH₂) _n -CHF₂ , (CH₂) _n -CH₂F, CH = CF₂, O (CH₂) _n -CH = CF₂, O (CH₂) _n CH = Cl₂, OC _n F _{2n + 1} , O (CF₂) _n -CF₂H, O (CH₂) _n -CF₃, O (CH₂) _n -CHF₂, O (CH₂) _n CH₂F, OCF = CF₂, SC _n F _{2n + 1} , S (CH₂) _n -CF₃, where n is 0 to 7.

If R is at least one substituted by halogen Alkyl, alkoxy or alkenyl radical, 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. With single substitution, the fluorine or chlorine substituent be in any position, but preferably in ω-position tion. Halogen is preferably chlorine or fluorine.

Compounds of formula I which are used for polymerization suitable wing groups R are suitable to represent liquid crystalline polymers.

Compounds of the formula I with branched wing groups R can occasionally due to better solubility in the usual liquid-crystalline base materials of importance be, but especially as chiral dopants if they are optically active. Smectic compounds of this type are suitable itself as components for ferroelectric materials.

Compounds of formula I with phases are suitable, for example wise for thermally addressed displays.  

Branched groups of this type usually do not contain more than a chain branch.

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

Among these compounds of formula I and the sub formulas are preferred in which at least one of the residues contained therein is one of the preferred Has meanings.

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

Some particularly preferred smaller groups from Verbin are those of sub-formulas II1 to II24:

The compounds of formula I are known per se Methods 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 Vol. IX, pp. 867 ff.) are described, under reaction conditions that are known and suitable for the implementations mentioned.

It is also possible to do so from those known per se, but not here make use of the variants mentioned.

Compounds according to the invention can, for. B. as follows are:  

Scheme 1

Scheme 2

Scheme 3

Scheme 4

The liquid-crystalline media according to the invention contain preferably in addition to one or more of the invention Compounds as further components 2 to 40, in particular 4 to 30 components. Very particularly preferably included these media in addition to one or more of the invention Connections 7 to 25 components. This further inventory parts are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, in particular their substances from the classes of azoxybenzenes, benzylidene anilines, biphenyls, terphenyls, phenyl or cyclohexylbenes zoate, cyclohexane-carboxylic acid phenyl or cyclohexyl ester, Phenyl or cyclohexyl esters of cyclohexylbenzoic acid, Phenyl or cyclohexyl ester of cyclohexylcyclohexane bonic acid, cyclohexyl phenyl ester of benzoic acid, cyclo hexanecarboxylic acid, or cyclohexylcyclohexanecarboxylic acid, Phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcy clohexane, cyclohexylcyclohexane, cyclohexylcyclohexylcyclo hexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclohexyl biphenyls, phenyl or cyclohexyl pyrimidines, phenyl or cyclohexylpyridines, phenyl- or cyclohexyldioxanes, Phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclo hexyl-2- (4-phenyl-cyclohexyl) ethane, 1-cyclohexyl-2- biphenylylethane, 1-phenyl-2-cyclohexyl-phenylethane, given otherwise halogenated stilbenes, benzylphenyl ether, tolanes and substituted cinnamic acids. The 1,4-phenylene groups in these compounds can also be fluorinated.

The most important as further components of the invention Media connections are possible through the Characterize formulas 1, 2, 3, 4 and 5:

R′-LER ′ ′ (1)
R′-L-COO-ER ′ ′ (2)
R′-L-OOC-ER ′ ′ (3)
R′-L-CH₂CH₂-ER ′ ′ (4)
R′-LC≡-ER ′ ′ (5)

In formulas 1, 2, 3, 4 and 5, L and E mean the same or can be different, each independently a bivalent residue from the from -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr-, -Dio-, -G-Phe- and -G-Cyc- as well whose mirror images formed group, whereby Phe unsubstituted ized 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, dio 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 mean.

One of the radicals L and E is preferably Cyc, Phe or Pyr. E is preferably Cyc, Phe or Phe-Cyc. Preferably included ten the media according to 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 simultaneously 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 residue is selected from the Group -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-, and optionally selected one or more components from the compounds of the formulas 1, 2, 3, 4 and 5, in which the Residues L and E are selected from the group -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-.  

R 'and R' 'mean in a smaller subgroup of ver bonds of formulas 1, 2, 3, 4 and 5 each independently from each other alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy with up to 8 carbon atoms. Hereinafter this smaller subgroup is called Group A and the Connections 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 residues mostly Is alkyl, alkenyl, alkoxy or alkoxyalkyl.

In another smaller group, referred to as group B, of the compounds of the formulas 1, 2, 3, 4 and 5, R ′ ′ -F, -Cl, -NCS or - (O) _i 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 the sub-formulas 1b, 2b, 3b, 4b and 5b. Those compounds of the sub-formulas 1b, 2b, 3b, 4b and 5b are particularly preferred 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 'the specified for the compounds of sub-formulas 1a-5a Meaning and is preferably alkyl, alkenyl, alkoxy or Alkoxyalkyl.

In another smaller subset of the compounds of the Formulas 1, 2, 3, 4 and 5 mean R ′ ′ -CN; this subset is hereinafter referred to as group C and the connection This subgroup is created with sub-formulas 1c, 2c, 3c, 4c and 5 c. In the connections of the R 'has sub-formulas 1c, 2c, 3c, 4c and 5c for the verb and the meanings of the sub-formulas 1a-5a preferably alkyl, alkoxy or alkenyl.  

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

The media according to the invention contain fiction compounds of formula I preferably one or several connections, which are selected from the group A and / or group B and / or group C. The mass fractions of the 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%, 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 each Media contained compounds from the Groups A and / or B and / or C preferably 5% to 90% and in particular 10% to 90%.

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

The media according to the invention are produced in yourself in the usual way. Usually the components dissolved in one another, expediently at elevated temperature. By The liquid-crystalline phases can be followed by suitable additives the invention can be modified so that it has been used in all known types of liquid crystal display elements can be used. Such additives are known to the person skilled in the art known and described in detail in the literature (H. Kelker / R. Hatz, Handbook of Liquid Crystals, Verlag Chemistry, Weinheim, 1980). For example, pleochroiti dyes for the production of colored guest-host systems or substances for changing the dielectric anisotrop 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, the transformation into chemical formulas taking place according to Tables A and B below. All residues C _n H _{2n + 1} and C _m H _2m1 are straight-chain alkyl residues with n or m C atoms. The coding according to Table B goes without saying. In Table A, only the acronym for the base body is given. In individual cases, there is a line for the substituents R¹, R², L¹ and L² separated from the acronym for the basic body:

Table A

The following examples are intended to illustrate the invention without limit them. Before and after mean percentanga ben weight percent. All temperatures are in degrees Celsius specified. Mp. Means melting point, Kp. = Clearing point. Further mean 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 visco sity (mm² / sec) was determined at 20 ° C.

"Usual work-up" means: You give if necessary Add water, extract with dichloromethane, diethyl ether Toluene, separates, dries the organic phase, evaporates and purifies the product by distillation under reduced Pressure or crystallization and / or chromatography. The following Abbreviations are used:

DAST Diethylaminosulfur trifluoride
DCC dicyclohexylcarbodiimide
DDQ dichlorodicyanobenzoquinone
DIBALH diisobutyl aluminum hydride
KOT potassium tertiary butanolate
PdCl₂ dppf 1,1'-bis (diphenylphosphino) ferrocene palladium (II) chloride
THF tetrahydrofuran
pTSOH p-toluenesulfonic acid
TMEDA tetramethylethylenediamine

example 1

0.02 mol I and 0.02 mol II are in 45 ml toluene and 21 ml Dissolved water and with 3.48 g of soda cookies and 0.6 g of tetra kis (triphenylphosphine) palladium (0) added and overnight cooked under reflux. Allow to cool to room temperature and filter the organic phase over diatomaceous earth. The fil is diluted with toluene and water and as usual worked up.  

The following compounds of the formula become analogous

manufactured:

Example 2

1.12 mol I in 1500 ml of THF: toluene = 1: 4 at 0 ° C 0.56 mol of zinc bromide and then 2.24 mol of lithium granules given. The is then stirred at 0-10 ° C. Mixture treated with ultrasound for 4 h. After additions from 0.56 mol II and 12.3 g PdCl₂-dppf, the cooling is removed and stirred for a further 72 h at room temperature. The mixture will poured into 100 ml of ammonium chloride and stirred for 15 min. The organic phase is separated off and worked up as usual.  

The following compounds of the formula become analogous

manufactured:

Claims (9)

1. benzene derivatives of the formula I, wherein
R QY, where
Q -O-, -S- or single bond
Y mono- or polyhalogenated alkyl or alkenyl with 2-12 C atoms
is
A¹ trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH² groups can also be replaced by -O- and / or -S-,
A² (a) an unsubstituted or single or multiple fluorinated 1,4-phenylene radical
(B) trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH₂ groups can be replaced by -O- and / or -S-
(c) residue from the group 1,4-cyclohexylene, 1,4-bicyclo [2.2.2] octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1 , 2,3,4-tetrahydronaphthalene-2,6-diyl,
Z¹ and Z² each independently of one another -CO-O-, -O-CO-, -CO-O-, -O-CO-, -CH₂O-, -OCH₂-, -CH₂CH₂-, -CH = CH-, -CH ≡C-, - (CH₂) ₄- or -CH = CH- CH₂CH₂- or a single bond,
L¹ and L² are each independently H or F, and
m 0, 1 or 2
means. 2. Compounds of formula I.
wherein L¹ and L² are fluorine. 3. Compounds of formula I, wherein R
-CH₂) _n CF₃, -CH = CHF, -O (CH₂) _n CF₃, -OCF = CF₂, -CH = CHCl, -CH = CCl₂, -CH = CF₂, -OCH = CF₂, where n is 0 to 7 is. 4. Compounds of formula IIa wherein
R, L¹ and L² have the meaning given in claim 1. 5. Compounds of the formula IIc wherein
R, L¹ and L² have the meaning given in claim 1. 6. Use of compounds of formula I as components liquid crystalline media. 7. Liquid crystalline medium with at least two liquid crystalline components, characterized in that it contains at least one compound of formula I.   8. Liquid crystal display element, characterized net that it is a liquid crystalline medium according to An saying 7 contains. 9. Electro-optical display element, characterized in that as a dielectric it is a liquid crystalline medium according to claim 7 contains.