DE4300066A1 - New fluorinated five-ring cpds. having high chemical, thermal and photo stability - e.g. 1,2-(di:fluoro-methylene di:oxy)-4-(trans-4-(trans-4-pentyl cyclohexyl) cyclohexyl) benzene, useful for liq. crystal display - Google Patents

Abstract

New fluorinated 5-ring cpds. R1-(A1-Z1)m-A2-Z2-W (I) where W = a condensed ring system of formula (IIA), (IIB) or (IIC). A3 = a cyclohexane, cyclohexene or phenyl ring; Q = C=O, CHF, CF2, CHR2 or CFR2; Q' = CF or CR2; R2 = 1-15C (fluoro)alkyl; Y1 = O or S; Y2 = O, CO, C=O or CHnF2-n; or, if Q = C=O, CHF or CF2, Y2 may also = CHR2 or CFR1; n = 0, 1 or 2; Y3 = N, CH or CF; or, if Q' = CF, Y3 may also = CR2; X = H, F or Cl; R1 = H or 1-15C alk(en)yl, which may have one CN or CF3 substit. or at least one halogen substit. and/or one or more CH2 gps. replaced by -O-, -S-, -CO-, a 1,3-cyclobutane ring, -CO-O-, -O-CO- or -O-CO-O-, so that hetero-atoms are not linked directly; A1 and A2 = (a) trans-1,4-cyclohexylne, in which one or more non-adjacent CH2 gps. may be replaced by -O- and/or -S-; (b) 1,4-phenylene in which one or two CH gps. may be replaced by N; or (c) a 1,4-cyclohexenylene, 1,4-bicyclo(2,2,2) -octylene, piperidin-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene -2,6-diyl or 1,2,3,4-tetrahydro naphthalene -2,6-diyl; in which the (a) and (b) gps. may be substd. by CN, Cl orF; Z1 and Z2 = -CO-O-, -O-CO-, -CH2O-, -O-CH2-, -CH2CH2-, -CH=CH-, -C=C- or a single bond; m = 0, 1 or 2; at least one of Y2, Y3, Q and Q' has F substit(s). USE/ADVANTAGE - (I) are used in liquid crystal (LC) media, which are used esp. in LCDs and as dielectric in electrooptical displays (claimed). (I) are LC or mesogenic cpds., which have good chemical, thermal and photo-stability, and are esp. suitable for TFT and STN displays. They give stable media and the thermal stability required for a high holding ratio.

Description

The invention relates to new fluorine-containing five-membered compounds of formula I.

R¹- (A¹-Z¹) _m -A²-Z²-W (I)

wherein

Y¹ O or S,
Y² O, S, C = O, CH _n F _2-n
n 0, 1 or 2,
Y³ N, CH or CF,
QC = O, CHF, CF₂, CHR², CFR²,
Q ′ CF or CR²,
R² is an unsubstituted or at least monosubstituted alkyl radical with 1-15 C atoms,
if QC = O, CHF or CF₂ Y² can also be CHR² or CFR²,
if Q ′ means CF, Y³ can also be CR²,
XH, F or Cl,
R¹ H, an unsubstituted, a simply by CN or CF₃ or an at least monosubstituted by halogen or alkyl or alkenyl radical having 1-15 carbon atoms, in which radicals one or more CH₂ groups each independently

can be replaced so that heteroatoms are not directly linked,
A¹ and A² each independently

• a) trans-1,4-cyclohexylene radical, in which also a or more non-adjacent CH₂ groups can be replaced by -O- and / or -S-,
• b) 1,4-phenylene radical, in which also one or two CH groups can be replaced by N,
• c) residue from the group 1,4-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 residues a) and b) can be substituted by CN, Cl or F,

Z¹ and Z² each independently of one another -CO-O-, -O-CO-, -CH₂O-, -O-CH₂-, -CH₂CH₂-, -CH = CH-, -C≡C- or a single bond, and
m 0, 1 or 2
means
with the proviso that at least one of the groups Y², Y³, Q and Q 'represents a radical with at least one F atom.

The invention further relates to the use of these compounds 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 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, the as components of liquid-crystalline media, in particular for TFT and STN displays.

The substances previously used for this purpose have always certain disadvantages, for example insufficient stability against the effects of heat, light or electrical Fields, unfavorable elastic and / or dielectric properties.

Especially for displays of the supertwist type (STN) with twist angles of significantly more than 220 ° so far used materials disadvantages.

It has now been found that the compounds of the formula I excellently suitable as components of liquid crystalline media are. With their help stable liquid crystalline Media, particularly suitable for TFT or STN displays. The new connections stand out especially characterized by a high thermal stability, which for a high holding ratio is advantageous.  

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 applications. 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 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.  

Above and below R¹, A¹, Z¹, m, A², Z² and W have the provided meaning, unless expressly stated otherwise is noted.

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

The compounds of formula I include compounds with two Rings of sub-formulas Ia and Ib:

R¹-A²-W (Ia)
R¹-A²-Z²-W (Ib)

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

R¹-A¹-A²-W (Ic)
R¹-A¹-A²-Z²-W (Id)
R¹-A¹-Z¹-A²-W (Ie)
R¹-A¹-Z¹-A²-Z²-W (If)

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

R¹-A¹-A¹-A²-W (Ig)
R¹-A¹-Z¹-A¹-A²-W (Ih)
R¹-A¹-A¹-Z¹-A²-W (Ii)
R¹-A¹-A¹-A²-Z²-W (Ij)
R¹-A¹-Z¹-A¹-Z¹-A²-W (Ik)
R¹-A¹-Z¹-A¹-A²-Z²-W (Il)
R¹-A¹-A¹-Z¹-A²-Z²-W (Im)
R¹-A¹-Z¹-A¹-Z¹-A²-Z²-W (In)

These include those of the sub-formulas Ia, Ic, Id, Ie, Ig, Ih and Ii preferred.

The preferred compounds of sub-formula Ia include those of the sub-formulas Iaa and Iab:

R¹-Phe-W (Iaa)
R¹-Cyc-W (Iab)

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

R¹-Phe-Z²-W (Iba)
R¹-Cyc-Z²-W (Ibb)

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

R¹-Cyc-Cyc-W (Ica)
R¹-Cyc-Phe-W (Icb)
R1-Phe-Phe-W (Icc)
R¹-Pyd-Phe-W (Icd)
R¹-Phe-Cyc-W (Ice)
R¹-Dio-Phe-W (Icf)
R¹-Pyr-Phe-W (Icg)

These include those of the formulas Ica, Icb, Icc and Ice particularly preferred.  

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

R¹-Cyc-Cyc-Z²-W (Ida)
R¹-Cyc-Phe-Z²-W (Idb)
R¹-Phe-Phe-Z²-W (Idc)
R¹-Pyr-Phe-Z²-W (Idd)
R¹-Pyd-Phe-Z²-W (Ide)
R¹-Cyc-Phe-CH₂CH₂-W (Idf)
R¹-A¹-Phe-CH₂CH₂-W (Idg)

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

R¹-Cyc-Z¹-Cyc-W (Iea)
R¹-A¹-CH₂CH₂-A²-W (Ieb)
R¹-Cyc-Z¹-Phe-W (Iec)
R¹-A¹-OCO-Phe-W (Ied)
R¹-Phe-Z¹-Phe-W (Iee)
R¹-Pyr-Z¹-A²-W (Ief)
R¹-Pyd-Z¹-A²-W (Ieg)
R¹-Dio-Z¹-A²-W (Ieh)

These include those of the sub-formulas Iea, Ieb, Iec and Iee particularly preferred.  

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

R¹-Phe-CH₂CH₂-A²-Z²-W (Ifa)
R¹-A¹-COO-Phe-Z²-W (Ifb)
R¹-Cyc-Z¹-Cyc-Z²-W (Ifc)
R¹-Phe-Z¹-Phe-Z²-W (Ifd)
R¹-Cyc-CH₂CH₂-Phe-Z²-W (Ife)

The preferred compounds of the sub-formulas Ig to In comprise those of the sub-formulas Io to Iv:

R¹-A¹-Cyc-Cyc-W (Io)
R¹-A¹-Cyc-Phe-W (Ip)
R¹-A¹-CH₂CH₂-A¹-Phe-W (Iq)
R¹-Cyc-Z¹-A¹-Z¹-Phe-W (Ir)
R1-Phe-Phe-Phe-W (Is)
R¹-Phe-Z¹-A¹-Phe-W (It)
R¹-A¹-Phe-Z¹-Phe-W (Iu)
R¹-A¹-Z¹-Cyc-Phe-Z²-W (Iv)

In the compounds of the formulas above and below means R¹ preferably alkyl, further preferably alkoxy.

A¹ and A² independently of one another are preferably Phe, Cyc, Che, Pyd, Pyr or Dio. The compounds preferably contain of formula I no more than one of the residues Bco, Pyd, Pyr, Dio or Dit.  

If the ring A¹ is present twice, the two rings can have the same or different meanings. The same applies also for the bridge Z¹.

Compounds of the formula I and all are also preferred Partial formulas in which A¹ and / or A² through once or twice F or CN means substituted 1,4-phenylene.

m is preferably 0 or 1, particularly preferably 1. X is preferably H or F, particularly preferred is H. Z¹ and Z² independently of one another are preferably -CH₂CH₂-, -CO-O-, -O-CO- or a single bond, particularly preferably one Single bond.

In the structural element W, A³ preferably denotes a cyclohexane or phenyl ring, particularly preferably a phenyl ring.

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

Y is preferably O, Y²O, CF₂ or S, in particular preferred for Y² is O and CF.

Q is preferably CF₂, C = O, CFR² or CHR², in particular CF₂ and C = O is preferred.  

If Q is C = O, CHF or CF₂, Y² is preferably also CHR² or CFR².

Q 'means CF or CR², preferably CR².

Y³ is preferably N or CF. If Q ′ is CF, Y³ preferably also CR².

At least one of the groups Y², Y³, Q and Q 'means one Rest, which has at least one F atom, so that the five-membered ring always carries at least one fluorine atom.

R² is preferably an alkyl or one by at least one F atom substituted alkyl group with 1-7 C atoms. In particular the residues methyl, trifluoromethyl, Ethyl, pentafluoroethyl, propyl, heptafluoropropyl, monofluoromethyl, Difluoromethyl, butyl, pentyl, hexyl or heptyl.

The formulas 1-12 represent particularly preferred meanings of Structure element W represents:

If R¹ in the formulas above and below is an alkyl radical and / or an alkoxy radical, it can straight chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and therefore means preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, Ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, further Methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, Tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, Undecoxy, dodecoxy, tridecoxy or tetradecoxy.

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-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R¹ 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 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 R¹ is an alkyl radical in which a CH₂ group is replaced by -O- and one by -CO-, these are preferably adjacent. Thus they contain an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. Preferably they 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, butoxycarbonyl, Pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, Propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxycarbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxycarbonyl) butyl.

If R¹ 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. Preferably it is straight-chain and has 4 to 13 carbon atoms. He means accordingly especially acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 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 R¹ is an alkyl substituted simply by CN or CF₃ or alkenyl radical, this radical is preferred straight chain and the substitution by CN or CF₃ in the ω-position.

If R1 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 Multiple substitution is preferably halogen F. The resulting ones 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 group R¹ 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.

Branched groups of this type usually do not contain more than a chain branch. Preferred branched residues R¹ 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.  

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 preferred are those in which at least one of the residues contained therein is one of the preferred ones indicated Has meanings.

In the compounds of formula I are those stereoisomers 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 of compounds of the formula I are those of the sub-formulas I1 to I12:

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) are described, and under reaction conditions for the reactions mentioned are known and suitable.

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

If desired, the starting materials can also be in situ are formed such that they can be removed from the reaction mixture not isolated, but immediately to the connections of the Formula I implements.

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

Scheme 1

Scheme 2

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 formula II, wherein Z¹ or Z² -CH = CH-, is used Aryl halide with an olefin around 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, in particular Bromides and iodides. The one for the success of the coupling reaction required tertiary amines, such as. B. triethylamine, are also suitable as solvents. As palladium catalysts are, for example, its salts, in particular Pd (II) - acetate, and organic phosphorus (III) compounds such. B. Triarylphosphanen suitable. You can do it in the present or Absence of an inert solvent at temperatures between approximately 0 ° and 150 °, preferably between 20 ° and 100 °, work; come as a solvent, for. B. nitriles such as acetonitrile or hydrocarbons such as benzene or toluene in Consider. The aryl halides used as starting materials and olefins are or can be widely available commercially be prepared by methods known from the literature, for example by halogenation of corresponding parent compounds or by elimination reactions on corresponding Alcohols or halides.  

In this way, stilbene derivatives can be produced, for example. The stilbenes can still be made by Reaction of a 4-substituted benzaldehyde with a corresponding phosphorylide according to Wittig. But you can also Prepare tolanes of formula I by replacing the olefin uses monosubstituted acetylene (Synthesis 627 (1980) or Tetrahedron Lett. 27, 1171 (1986)).

Aryl halides can also be used to couple aromatics Aryltin compounds are implemented. These are preferred Reactions with the addition of a catalyst such. B. one Palladium (0) complex in inert solvents such as hydrocarbons at high temperatures, e.g. B. in boiling Xylene, carried out under a protective gas.

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

Tolanes of the formula I in which Z¹ or Z² are -C≡C- can also on the Fritsch-Buttenberg-Wiechell rearrangement (Ann. 279, 319, 1984) in which 1,1-diaryl-2- halogenethylenes are rearranged to diarylacetylenes in Presence of strong bases.

Tolanes of formula I can also be prepared by: the corresponding style level is brominated and then one Subjects to dehydrohalogenation. You can do it yourself well-known variants of this implementation, which are not mentioned here apply.  

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 one Excess aqueous or aqueous-alcoholic NaOH or KOH at temperatures between about 20 ° and 100 °.

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

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, the  Cyclohexane carboxylic acid, or cyclohexylcyclohexane carboxylic acid, Phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, Cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, 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-cyclohexyl 2- (4-phenyl-cyclohexyl) -ethane, 1-cyclohexyl-2-biphenylylethane, 1-phenyl-2-cyclohexylphenylethane, optionally halogenated stilbenes, benzylphenyl ether, tolanes and substituted cinnamic acids. The 1,4-phenyl 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, 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 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 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 ″ 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, R ″ -F, -Cl, -NCS or - (O) _i CH _{3- (k + 1)} F _k Cl₁ , where i is 0 or 1 and k + 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 common with other variants of the proposed substituents. 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%,
especially 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 Compounds containing media according to the invention from the Groups A and / or B and / or C preferably 5% -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 containing are also preferred more than 40%, in particular 45 to 90%, of the invention Links. 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 Chemie, 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 methylene chloride, 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:
NBS N-bromosuccinimide
PdCl₂ (dppf) (diphenylphosphinoferrocene) palladium dichloride
PE petroleum ether
THF tetrahydrofuran

Example 1

a) 0.487 mol of 1,2-methylenedioxybenzene and 0.512 mol of NBS are together in 250 ml of CHCl₃ for three hours Heated to reflux.

The mixture is left to stand overnight and the reaction solution is evaporated a. The residue is taken up in PE / H₂O, with H₂O washed, dried, filtered through silica gel and rotated in. The residue is distilled and is obtained 1,2-methylenedioxy-4-bromobenzene.

b) 30 mmol 1,2-methylenedioxy-4-bromobenzene are combined heated to 90 ° C with 30 mmol PCl₅, and after the end Gas evolution is stirred for a further 1 hour. To Purification by distillation gives 1,2-dichloromethylenedioxy 4-bromobenzene.

This compound is converted into dioxane by reaction with SbF₃ converted into the 1,2-difluoromethylene dioxy-4-bromobenzene.

c) A mixture of 0.075 mol of trans-4- (trans-4-pentylcyclohexyl) - cyclohexyl bromide, 0.180 mol lithium, 0.030 mol ZnBr₂ and 150 ml of THF / toluene (1/4) is under a nitrogen atmosphere Treated with ultrasound at 5 ° C for 2 hours.  

Then 0.06 mol of 1,2-difluoromethylenedioxy-4-bromobenzene and 1.05 g PdCl₂ (dppf) added. Stir for 2 hours at 5 ° C and overnight at room temperature. After spinning in and filtering through silica gel (PE) is obtained by chromatographic purification of 1,2- (difluoromethylene dioxy) - -4- [trans-4- (trans-4-pentylcyclohexyl) cyclhexyl] benzene with K 77 ° N 93.6 ° I.

Examples 2 to 14

Analogously to Example 1, the following compounds according to the invention are obtained from the corresponding precursors:

Example 15

A mixture of 0.043 mol (trans-4-pentylcyclohexyl) phenylboronic acid, 0.043 mole of 1,2-difluoromethylene dioxy-4-bromobenzene (prepared according to Example 1a-1b), 75 ml toluene, 37.5 ml EtOH, 0.086 mol Na₂CO₃ · 10 H₂O + 24 ml H₂O and 0.53 g Pd (PPh₃) ₄ Heated under reflux for 20 hours, then with PE the usual Refurbished. After cleaning over silica gel (Hexane) gives 1,2- (difluoromethylene dioxy) -4- [4- (trans- 4-pentylcyclohexyl) phenyl] benzene with K 69 ° N 81 ° I.

Examples 16-29

Analogously to Example 15, the following compounds according to the invention are obtained from the corresponding precursors:

Examples 30-59

Analogously to Examples 1 and 15, the corresponding Precursors the following compounds of the invention:

Claims (6)

1. Fluorine-containing five-membered compounds of the formula I R¹- (A¹-Z¹) _m -A²-Z²-W (I) in which Y¹ O or S,
Y² O, S, C = O, CH _n F _2-n
n 0, 1 or 2,
Y³ N, CH or CF,
QC = O, CHF, CF₂, CHR², CFR²,
Q ′ CF or CR²,
R² is an unsubstituted or at least monosubstituted alkyl radical with 1-15 C atoms
if QC = O, CHF or CF₂ Y² can also be CHR² or CFR²,
if Q ′ means CF, Y³ can also be CR²,
XH, F or Cl,
R¹ H, an unsubstituted, a simply by CN or CF₃ or an at least monosubstituted by halogen or alkyl or alkenyl radical having 1-15 carbon atoms, in which radicals one or more CH₂ groups each independently can be replaced so that heteroatoms are not directly linked,
A¹ and A² 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 residues a) and b) can be substituted by CN, Cl or F,

Z¹ and Z² each independently of one another -CO-O-, -O-CO-, -CH₂O-, -O-CH₂-, -CH₂CH₂-, -CH = CH-, -C≡C- or a single bond, and
m 0, 1 or 2
means, with the proviso that at least one of the groups Y², Y³, Q and Q 'means a radical with at least one F atom. 2. Use of compounds of formula I according to claim 1 as components of liquid crystalline media. 3. Liquid-crystalline medium with at least two liquid-crystalline ones Components, characterized in that it contains at least one compound of formula I.   4. liquid crystal display element, characterized in that it is a liquid crystalline medium according to claim 3 contains. 5. Electro-optical display element, characterized in that as a dielectric it is a liquid crystalline medium according to claim 3 contains.