DE4206765A1 - Novel penta:fluoro:ethyl:ketone derivs. - useful as low viscosity components of liq. crystal mixts. - Google Patents

Abstract

Pentafluoroethylketones of formula (I) R-(A1-Z1)m-A2-Z2-A3-CO-C2F5 where R = H or 1-15C alkyl or alkenyl opt. monosubstd. by CN or CF3 or substd. at least once by halogen and opt. with 1 or more CH2 replaced by -O-, -S-, 1,3-cyclobutylene, -CO-, -CO-O-, -O-CO- or -O-CO-O-, such that O atoms are not directly bonded to each other; A1-A3 = (a) trans-1,4-cyclohexylene opt. substd. by 1 or 2 F and opt. with 1 or more non-adjacent CH2 replaced by -O- and/or -S-; (b) 1,4-phenylene opt. substd. by 1 or 2F and opt. with 1 or 2 CH replaced by N; or (c) 1,4-cyclohexylene, 1,4-bicyclo(2,2,2) octylene, piperidin-1,4-diyl, naphthalene-2,6-diyl, decahydro-naphthalene-2,6-diyl, or 1,2,3,4-tetrahydro naphthalene-2,6-diyl; Z1 and Z2 = -CO-O-, -O-CO-, -CH2O-, -O-CH2-, -CH2-CH2-, -CH=CH-, -C=C- or a single bond, opty. with 1 of Z1 and Z2 also being -(CH24- or -CH=CH-CH2-CH2-; and m = 0, 1 or 2. USE/ADVANTAGE - Use of (I) is claimed as a component in a liq. crystal mixt., as are also liq. crystal displays and electro-optical displays contg. such mixts.. (I) are of low viscosity and relatively high dielectric anisotropy and give stable liq. crystal media with broad mesophase range

Description

The invention relates to pentafluoroethyl ketones of the formula I,

R- (A¹-Z¹) _m -A²-Z²-A³-CO-C₂F₅ (I)

wherein
RH, an unsubstituted, an alkyl or alkenyl radical with 1 to 15 carbon atoms which is simply substituted by CN or CF₃ or an at least monosubstituted by halogen, wherein one or more CH₂ groups in these radicals are each independently of one another by -O-, - S-,

-CO-, -CO-O-, -O-CO- or -O-CO-O- can be replaced so that O atoms are not directly linked to each other,
A¹, A² and A³ each independently

• (a) trans-1,4-cyclohexylene radical, in which also one or several non-adjacent CH₂ groups by -O- and / or -S- can be replaced,  
• (b) 1,4-phenylene, which also includes one or two CH groups can be replaced by N,
• (c) radical from the group 1,4-cyclohexenylene, 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,

where the radicals (a) and (b) can be substituted by one or two fluorine,
Z¹ and Z² each independently of one another -CO-O-, -O-CO-, -CH₂O-, -OCH₂-, -CH₂CH₂-, -CH = CH-, -C≡C- or a single bond, one of the radicals Z¹ and Z² also - (CH₂) ₄- or -CH = CH-CH₂CH₂- and
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 media according to the invention contain.  

The compounds of formula I can be used as components liquid crystalline media are used, especially for Displays based on the principle of the twisted cell, the Guest-host effect, the effect of deformation erect Phases or the effect of dynamic scattering.

The invention was based, new stable task find liquid-crystalline or mesogenic compounds, which are suitable as components of liquid-crystalline media and in particular 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 liquids can be made crystalline media with wide mesophase range and advantage adhere values for the optical and dielectric anisotropy receive. These media also have a very good low temperature behavior on.

DE 41 01 600 A1 describes connections with a terminal CO-CF₂-alkyl group such as. B.

mentioned.  

Connections of the formulas

are described in DE-OS 40 06 921.

In DE-OS 40 23 106 the following connections

disclosed.  

With regard to the most diverse areas of application Compounds with high Δε, however, it was desirable further connections with high nematogenicity are available to have that exactly tailored to the respective applications have tailored properties.

With the provision of compounds of formula I will also generally the range of liquid crystalline Substances that can be found under various application technology Aspects for the production of liquid crystalline Mixtures are suitable, considerably widened.

The compounds of formula I have a wide range of uses Area. Depending on the choice of substituents can use these compounds as base materials serve from which liquid-crystalline media predominantly Part are composed; but connections can also be made of the formula I liquid crystalline base materials other classes of compounds can be added, for example the dielectric and / or optical anisotropy of a to influence such dielectric and / or in order to To optimize threshold 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 range. 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 Components of 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, in particular electro-optical Display elements that contain such media.

For the sake of simplicity, in the following Y mean CO-C₂F₅, Cyc is 1,4-cyclohexyl, Che is 1,4-cyclohexenylene rest, Dio a 1,3-dioxane-2,5-diyl residue, Dit one 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 Bi is a bicyclo (2,2,2) octylene radical, where Cyc and / or Phe unsubstituted or single or double by F or CN can be substituted.

A¹, A² and A³ are preferably selected from the group Cyc, Che, Phe, Pyr, Pyd and Dio, preferably only one of the residues A¹ and A² in the molecule are Che, Phe, Pyr, Pyd or Dio is. A³ is preferred

R is preferably alkyl, furthermore alkoxy.

The compounds of formula I accordingly include Connections with two rings of sub-formulas Ia and Ib:

R-A²-A³-Y (Ia)
R-A²-Z²-A³-Y (Ib)

Connections with three rings of sub-formulas Ic to If:

R-A¹-A²-A³-Y (Ic)
R-A¹-Z¹-A²-Z²-A³-Y (Id)
R-A¹-Z¹-A²-A³-Y (Ie)
R-A¹-A²-Z²-A³-Y (If)

as well as compounds with four rings of the sub-formulas Ig to Im:

R-A¹-A¹-A²-A³-Y (Ig)
R-A¹-Z¹-A¹-A²-A³-Y (Ih)
R-A¹-A¹-Z¹-A²-A³-Y (Ii)
R-A¹-A¹-A²-Z¹-A³-Y (Ij)
R-A¹-Z¹-A¹-Z¹-A²-A³-Y (Ik)
R-A¹-A¹-Z¹-A²-Z²-A³-Y (Il)
R-A¹-Z¹-A¹-Z¹-A²-Z²-A³-Y (Im)

These include in particular those of sub-formulas Ia, Ib, Ic, Id, Ie, If, Ii and Il preferred.

The preferred compounds of sub-formula Ia include those of the sub-formulas Iaa to Iah:

R-Phe-A³-Y (Iaa)
R-Phe-A³-Y (Iab)
R-Dio-A³-Y (Iac)
R-Pyr-A³-Y (Iad)
R-Pyd-A³-Y (Iae)
R-Cyc-A³-Y (Iaf)
R-Cyc-A³-Y (Iag)
R-Che-A³-Y (Iah)

These include those of the formulas Iaa, Iab, Iac, Iad, Iaf and Iag is particularly preferred.

The preferred compounds of sub-formula Ib include those of the sub-formulas Iba and Ibb:

R-Cyc-CH₂CH₂-A³-Y (Iba)
R-Cyc-COO-A³-Y (Ibb)

The preferred compounds of sub-formula Ic include those of the sub-formulas Ica to Ico:

R-Phe-Phe-A³-Y (Ica)
R-Phe-Phe-A³-Y (Icb)
R-Phe-Dio-A³-Y (Icc)
R-Cyc-Cyc-A³-Y (Icd)
R-Phe-Cyc-A³-Y (Ice)
R-Cyc-Cyc-A³-Y (Icf)
R-Pyd-Phe-A³-Y (Icg)
R-Pyr-Phe-A³-Y (Ich)
R-Phe-Pyr-A³-Y (Ici)
R-Cyc-Pyr-A³-Y (Icj)
R-Cyc-Phe-A³-Y (Ick)
R-Cyc-Phe-A³-Y (Icl)
R-Dio-Phe-A³-Y (Icm)
R-Che-Phe-A³-Y (Icn)
R-Phe-Che-A³-Y (Ico)

These include those of the formulas Ica, Icc, Icd, Ice, Ici and Icj particularly preferred.  

The preferred compounds of sub-formula Id include those of the sub-formulas Ida to Idm:

R-Phe-Z¹-Phe-A³-Y (Ida)
R-Phe-Z¹-Phe-A³-Y (Idb)
R-Phe-Z¹-Dio-Z¹-A³-Y (Idc)
R-Cyc-Z¹-Cyc-Z¹-A³-Y (Idd)
R-Cyc-Z¹-Cyc-Z¹-A³-Y (Ide)
R-Pyd-Z¹-Phe-Z¹-A³-Y (Idf)
R-Phe-Z¹-Pyd-Z¹-A³-Y (Idg)
R-Pyr-Z¹-Phe-Z¹-A³-Y (Idh)
R-Phe-Z¹-Pyr-Z¹-A³-Y (Idi)
R-Phe-Z¹-Cyc-Z¹-A³-Y (Idj)
R-Cyc-Z¹-Phe-Z¹-A³-Y (Idk)
R-Cyc-Z¹-Phe-Z¹-A³-Y (Idl)
R-Dio-Z¹-Phe-Z¹-A³-Y (Idm)

The preferred compounds of sub-formula Ie include those of the sub-formulas Iea to Iel:

R-Pyr-Z¹-Phe-A³-Y (Iea)
R-Dio-Z¹-Phe-A³-Y (Ieb)
R-Phe-Z¹-Phe-A³-Y (Iec)
R-Cyc-Z¹-Phe-A³-Y (Ied)
R-Cyc-Z¹-Phe-A³-Y (Iee)
R-Phe-Z¹-Cyc-A³-Y (Ief)
R-Cyc-Z¹-Cyc-A³-Y (Ieg)
R-Cyc-Z¹-Cyc-A³-Y (Ieh)
R-Phe-Z¹-Dio-A³-Y (Iei)
R-Pyd-Z¹-Phe-A³-Y (Iej)
R-Phe-Z¹-Pyr-A³-Y (Iek)
R-Cyc-Z¹-Pyr-A³-Y (Iel)

The preferred compounds of sub-formula If include those of the sub-formulas Ifa to Ifr:

R-Pyr-Phe-Z¹-A³-Y (Ifa)
R-Pyr-Phe-OCH₂-A³-Y (Ifb)
R-Phe-Phe-Z¹-A³-Y (Ifc)
R-Phe-Phe-OOC-A³-Y (Ifd)
R-Phe-Phe-Z¹-A³-Y (Ife)
R-Cyc-Cyc-Z¹-A³-Y (Iff)
R-Cyc-Cyc-Z¹-A³-Y (Ifg)
R-Cyc-Cyc-CH₂CH₂-A³-Y (Ifh)
R-Pyd-Phe-Z¹-A³-Y (Ifi)
R-Dio-Phe-Z¹-A³-Y (Ifj)
R-Phe-Cyc-Z¹-A³-Y (Ifk)
R-Phe-Cyc-Z¹-A³-Y (Ifl)
R-Phe-Pyd-Z¹-A³-Y (Ifm)
R-Che-Phe-Z¹-A³-Y (Ifn)
R-Phe-Che-Z¹-A³-Y (Ifo)
R-Cyc-Phe-Z¹-A³-Y (Ifp)
R-Cyc-Phe-OOC-A³-Y (Ifq)
R-Cyc-Phe-Z¹-A³-Y (Ifr)

Compounds of the formula I and all are also preferred Partial formulas in which A¹ and / or A² 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-phenylene and 3-cyan-1,4-phenylene. In a particularly preferred Embodiment is A² 3,5-difluoro-1,4-phenylene and m 1 or 2.  

Z¹ and Z² are preferably a single bond, -CO-O-, -O-CO- and -CH₂CH₂-, preferably second -CH₂O- and -OCH₂-.

If one of the residues Z¹ and Z² - (CH₂) ₄- or -CH = CH-CH₂CH₂- means, the other radical is Z¹ or Z² (if present) preferably the single bond.

Preferred compounds of this type correspond to the part formula I ′

wherein Z² - (CH₂) ₄-, - (CH₂) ₄- -CH = CH-CH₂CH₂- or a simple bond L¹ and L² each independently of one another H or F mean and R, A¹, A², Z¹ and m are those given in formula I. Have meaning. The preferred meanings for R, A¹, A² and m correspond to those for the compounds of formula I.

m is preferably 1 or 0, particularly preferably 0.  

If R is an alkyl radical and / or an alkoxy radical, it can be straight or branched. Preferably it is 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, pentoxy, hexoxy or Heptoxy, also methyl, octyl, nonyl, decyl, undecyl, Dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, Nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetra decoxy.

Oxaalkyl preferably means 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-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-ocadecyl.

If R is an alkyl radical in which a CH₂ group is replaced by -CH = CH-, it can be straight-chain or be branched. It is preferably straight-chain and has 2 up to 10 carbon atoms. 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.  

If R is an alkyl radical in which a CH₂ group is replaced by -O- and one by -CO-, these are preferably adjacent. Thus, they include an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. Preferential these are 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-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 neighboring CH₂ group replaced by CO or CO-O or O-CO , it can be straight-chain or branched. It is preferably straight-chain and has 4 to 13 carbon atoms. It means especially acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxy heptyl, 8-acryloyloxyoctyl, 9-acryloyloxynonyl, 10-acryloyloxydecyl, methacryloyloxymethyl, 2-metha cryloyloxyethyl, 3-methacryloyloxypropyl, 4-methacryloyloxy butyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoctyl, 9-methacryloyloxynonyl.  

If R is a simply substituted by CN or CF₃ alkyl or alkenyl radical, this radical is preferred straight chain and the substitution by CN or CF₃ in ω position.

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

Compounds of 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 S _A phases are suitable for example for thermally addressed displays.

Branched groups of this type usually do not contain more than a chain branch. Preferred branched residues R are 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 can be straight-chain or branched. It is preferably branched and has 3 to 12 carbon atoms. So it means 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-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 (methoxy carbonyl) 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 (ethoxy carbonyl) butyl, 5,5-bis (ethoxycarbonyl) hexyl.

Compounds of formula I which are used for polycondensation suitable wing groups R are suitable for illustration liquid crystalline polycondensates.

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 one of the preferred Has meanings.  

In the compounds of formula I, those are stereo isomers 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 included, each enclose the two 2,5-position isomers.

Some particularly preferred smaller groups of Compounds are those of sub-formulas I1 to I21:

The 1,4-cyclohexenylene group preferably has the following Structures:

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, p. 867 ff.) are described, under reaction conditions that are known and suitable for the above-mentioned implementations.

It is also possible to do this from well-known ones, but not here make use of the variants mentioned.

The compounds of the invention can e.g. B. made by using a compound of formula II,

wherein R, A¹, A², Z¹, Z² and m have the meaning given and x represents 1, 2, 4 or 4 according to the following reaction scheme with pentafluoropropanoic acid chloride under Friedel-Crafts Implements conditions.

Scheme 1

Further synthetic methods are obvious to the person skilled in the art. For example, appropriately substituted 1,3-difluorobenzene compounds or monofluorinated analogs (L = H) can be converted into the 1,3-difluoro compounds or monofluorinated analogs (L = H) in the 5-position and the rest R - (A¹-Z¹) _m -A²-Z² are subsequently introduced by reactions customary in liquid crystal chemistry (e.g. couplings according to the article E. Poetsch, contacts (Darmstadt) 1988 (2), p. 15).

The compounds of formula II can, for example, according to following synthesis schemes are prepared:

Scheme 2

(A = - (- A¹-Z¹) _m -A²- / Z² = -CH₂CH₂- / L¹, L² = H or F)

Scheme 3

(A = - (- A¹-Z¹) _m -A²- / Z² = single bond / L¹, L² = H or F)

Scheme 4

Scheme 5

Scheme 6

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) be preserved.  

The corresponding carboxylic acids and alcohols or phenols are known or can be used in analogy to known methods getting produced.

In another process for making the compounds of the formula I, an aryl halide is reacted with an olefin in the presence of a tertiary amine and a palladium catalyst (see R. F. Heck, Acc. Chem. Res. 12 (1979) 146). Suitable aryl halides are, for example, chlorides, Bromides and iodides, especially bromides and iodides. The for the success of the coupling reaction required tertiary Amines such as B. triethylamine, are also suitable as solvents. Examples of these are as palladium catalysts Salts, especially Pd (II) acetate, with organic phosphorus (III) compounds such. B. Triarylphosphanen suitable. You can do this in the presence or absence of an inert Solvent at temperatures between about 0 ° and 150 ° C, preferably between 20 ° and 100 ° C; as a solvent come z. B. nitriles such as acetonitrile or hydrocarbons such as benzene or toluene. As Aryl halides and olefins used as starting materials are widely available commercially or can according to literature Processes are produced, for example by Halogenation of the corresponding parent compound or by Elimination reactions on corresponding alcohols or Halides.  

Ether of the formula I are corresponding by etherification Hydroxy compounds, preferably corresponding phenols, available, the hydroxy compound expediently first in a corresponding metal derivative, e.g. B. by treatment with NaH, NaNH₂, NaOH, KOH, Na₂CO₃ or K₂CO₃ in the corresponding Alkali metal alcoholate or alkali metal phenolate transferred becomes. This can then be combined with the corresponding alkyl halide, sulfonate or dialkyl sulfate are implemented, advantageously in an inert solvent such as. B. acetone, 1,2-dimethoxyethane, DMF or dimethyl sulfoxide or with an excess of aqueous or aqueous-alcoholic NaOH or KOH Temperatures between about 20 ° C and 100 ° C.

The starting materials are either known or can be found in Analogy to known compounds.

The compounds of formula I 'with Z² = - (CH₂) ₄- can following scheme:

Scheme 7

In the Pd (II) -catalyzed coupling reaction, either directly the target product I 'formed or a preliminary product, in this is completely analogous to the above methods for connections or Formula I the rest -Y is introduced.

The compounds of formula I 'with Z² = -CH = CH-CH₂CH₂- can Wittig can still be produced according to the following scheme:

Scheme 8

The synthesis of some particularly preferred compounds is specified below:

Scheme 9

Scheme 10 (L₁, L₂ = H or F)

Scheme 11

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. These other ingredients 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 cyclohexylbenzoates, Phenyl or cyclohexyl cyclohexane-carboxylic acid, Phenyl or cyclohexyl esters of cyclohexylbenzoic acid, Phenyl or cyclohexyl esters of cyclohexylcyclohexane carboxylic acid, Cyclohexyl phenyl ester of benzoic acid, cyclohexane carboxylic acid or cyclohexylcyclohexane carboxylic acid, Phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, Cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis- cyclohexylbiphenyls, phenyl- or cyclohexylpyrimidines, Phenyl- or cyclohexylpyridines, phenyl- or cyclohexyldioxanes, Phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclohexyl-2- (4-phenyl-cyclohexyl) ethane, 1-cyclohexyl-2- biphenylethane, 1-phenyl-2-cyclohexylphenylethane, optionally 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≡CER ″ (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, with Phe 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, 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 mean.

One of the radicals L and E is preferably Cyc, Phe or Pyr. It is preferably Cyc, Phe or Phe-Cyc. Preferably included 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 one or more components are selected at the same time 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 subset of the compounds of formulas 1, 2, 3, 4 and 5 each independently Alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or Alkanoyloxy with up to 8 carbon atoms. The following will this smaller subgroup called A and the compounds are with the partial formulas 1a, 2a, 3a, 4a and 5a designated. For most of these compounds, R 'and R ″ differ from each other, with one of these residues mostly Is alkyl, alkenyl, alkoxy or alkoxyalkyl.

In another, referred to as group B, smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5 means 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 in which R ″ has the meaning -F, -Cl, -NCS, -CF₃, -OCHF₂ or -OCF₃ are particularly preferred.

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 Formulas 1, 2, 3, 4 and 5 mean R ″ -CN; this subset is referred to below as group C and the compounds this sub-group are correspondingly with sub-formulas  1c, 2c, 3c, 4c and 5c. In the connections of the R 'has sub-formulas 1c, 2c, 3c, 4c and 5c for the compounds of the sub-formulas 1a-5a and meaning 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 available in analogy.

The media according to the invention contain, besides those according to the invention 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 according to the invention from the Groups A and / or B and / or C preferably 5 to 90% and is in particular 10 to 90%.  

The media according to the invention preferably contain 1 to 40%, particularly preferably 5 to 30%, of the invention Links. Media are also preferred, containing more than 40%, in particular 45 to 90% compounds of 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. As a rule, 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, pleochroic Dyes for the production of colored guest-host systems or substances for changing the dielectric anisotropy, the viscosity and / or the orientation of the nematic Phases are added.

The following examples are intended to illustrate the invention without limit them. Above and below mean percentages Percent by weight. 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 details 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, extract with dichloromethane, diethyl ether or 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
THF tetrahydrofuran
pTSOH p-toluenesulfonic acid
TMEDA tetramethylethylenediamine

Example 1

0.1 mol of 4- [trans-4-n-pentylcyclohexyl] phenyl bromide in 600 ml of diethyl ether / THF (1: 1) are cooled to -75 ° C. under N₂. Then 0.13 mol BuLi (15% in hexane) is slowly added dropwise. After stirring for 1 h at -75 ° C., 0.13 mol of methyl pentafluorophosphate are added dropwise and the mixture is added dropwise for 2 hours. After stirring at -75 ° C for 1 h, 0.13 mol of methyl pentafluorophosphate are added dropwise and the mixture is stirred at -75 ° C for another 2 h. Then allowed to warm to -60 ° C and mixed with 20 ml of ethanolic HCl. The organic phase is then separated off and worked up as usual.
K102 N 163.1 I, Δn = +0.127.

The following compounds of the formula become analogous

produced:

Example 2

0.02 mol of trans, trans-4-pentylcyclohexylcyclohexane methyl ester and then 0.1 mol of methyl lithium lithium bromide complex are added dropwise to 120 ml of diethyl ether and 0.102 mol of pentafluoroethyl iodide at -78 ° C. The mixture is then stirred at -75 ° C for 1.5 h. After adding 250 ml of 10% HCl, the organic phase is separated and worked up as usual.
K 66 I, Δn = +0.036

The following compounds of the formula become analogous

produced:

Claims (7)

1. Pentafluoroethyl ketones of the formula I, R- (A¹-Z¹) _m -A²-Z²-A³-CO-C₂F₅ (I) in which
RH, an unsubstituted, an alkyl or alkenyl radical with 1 to 15 carbon atoms which is simply substituted by CN or CF₃ or an at least monosubstituted by halogen, wherein one or more CH₂ groups in these radicals are each independently of one another by -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- can be replaced so that O atoms are not directly linked to each other,
A¹, A² and A³ each independently

• (a) trans-1,4-cyclohexylene radical, in which one or more non-adjacent CH₂ 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-cyclohexenylene, 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,

where the radicals (a) and (b) can be substituted by one or two fluorine,
Z¹ and Z² each independently of one another -CO-O-, -O-CO-, -CH₂O-, -OCH₂-, -CH₂CH₂-, -CH = CH-, -C≡C- or a single bond, one of the radicals Z¹ and Z² also - (CH₂) ₄- or -CH = CH- CH₂CH₂-, and
m 0, 1 or 2
means. 2. Compounds of formula I ' wherein L¹ and L² independently represent H or F and R, A¹, A², Z¹, Z² and m have the meaning given in claim 1. 3. Use of compounds of formula I as components liquid crystalline media. 4. Liquid-crystalline medium with at least two liquid-crystalline ones Components, characterized in that it contains at least one compound of the 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 in that it is a liquid crystalline dielectric Contains medium according to claim 4.