DE3913554A1 - New bi:phenylyl:ethane cpds. - for use in liq. crystal phases having large optical anisotropy and increased stability - Google Patents

Abstract

New biphenylylethane cpds. of formula (I) are claimed where R = alk(en)yl, fluoroalkyl or oxaalkyl; M = 1 or 2; Y = 0, S, CO-0, 0-C0, 0-C0-0, a bond, or, if m = 1, trans-1,4-cyclohexylene; ph = 1,4-phenylene, or 2-fluoro-, 3-fluoro- or 3,5-difluoro-1,4-phenyle-ne; L1, L2, L3, = H, or one may = F; L4 = H or F; X = F, C1, CF3, CN, OCF3, OCHF2, NCS or NO2, and if (a) X = CN, then Y = trans-1,4-cyclohexylene or m = 2 and/or ph-X = 2-fluoro-, 3-fluoro- or 3,5-difluoro-4-cyanophenyl and/or 1 or 2 of the L gps. = F, and (b) if X = NCS, then Y = trans-1,3-cyclohexylene or m = 2 and/or ph-X = 2-fluoro-, 3-fluoro- or 3,5-difluoro-4-isothiocyanatophenyl and/or 1 or 2 of the L gps. = F and/or -Y-R = 1-3C straight-chain alkyl. USE/ADVANTAGE - Use of (I) as components of liq. crystal phases, contg. at least 2 liq. crystal components, one of which is (I), and liq. crystal recording units contg. the multi-component liq. crystal phase, are claimed. The liq. crystal phases are esp. used in displays, partic. in mixts, based on the supertwist effect . (I) are also components for smectic liq. crystal phases, and are intermediates for other substances for use as components of liq. crystal phases. (I) are stable (chemically, termally and to light) liq. crystal or mesogenic cpds. with high double refraction, giving liq. crystal phases with relatively large optical anisotropy, positive dielectric anisotropy, low viscosity and high nematogen-isity, combined with good low temp. behaviour.

Description

The invention relates to biphenylylethanes of the formula I,

wherein
R is alkyl, fluoroalkyl, alkenyl or oxaalkyl,
m 1 or 2,
Y, S, CO-O, O-CO, O-CO-O, a single bond, or - in the case of m = 1 - also trans-1,4-cyclohexylene,
Each Ph identical or different radicals selected from the group consisting of 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene and 3,5-difluoro-1,4-phenylene,
L¹, L² L⁴ each H, or one of these radicals also F,
L⁴H or F and
X is F, Cl, -CF₃, -CN, -OCF₃, -OCHF₂, -NCS or -NO₂, with the proviso that

• a) in the case X = -CN Y trans-1,4-cyclohexylene or m = 2 and / or Ph-X 2-fluoro-4-cyanophenyl, 3-fluoro-4-cyanophenyl or 3,5-difluoro-4- cyanophenyl and / or one or two of the radicals L¹, L², L³ and L⁴ is F and
• b) in the case of X = NCS, Y = trans-1,4-cyclohexylene or m = 2 and / or Ph-X 2-fluoro-4-isothiocyanatophenyl, 3-fluoro-4-isothiocyanatophenyl or 3,5-difluoro-4 - Isothiocyanatophenyl and / or one or two of the radicals L¹, L², L³ and L⁴ F and / or -YR straight-chain alkyl having up to 3 carbon atoms.

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

Similar compounds are for. B. from DE-OS 30 40 632 known. However, the compounds described there are no biphenylylethanes, but cyclohexylphenylethanes.

Compounds of the formula

wherein R¹ is n-alkyl or n-alkoxy, are known from DE-OS 26 17 593. Compounds of the same formula in which R¹ is branched alkyl are known from DE-OS 27 36 772 as thermochromic materials or from JP 62-1 46 984 as materials for ferroelectric S _c mixtures.

Compounds of the formula

in which R¹ is n-pentyloxy, 2-methylbutyl, n-butyl, n-pentyl, n-hexyl and n-heptyl are from the EP-OS 02 27 004 known.

The invention was based on the object new stable liquid crystalline or mesogenic compounds with high Birefringence found as components of liquid crystalline Phases are suitable. This task was by providing the compounds of the formula I solved.

It has been found that the compounds of the formula I as Components of liquid-crystalline phases are particularly suitable are. In particular, they are stable liquid crystalline with their help Phases with relatively high optical anisotropy, positive dielectric anisotropy, low viscosity and high nematogeneity in combination with favorable Cryogenic behavior can be produced. The substances of the formula I are for example particularly preferred for the use in mixtures for Supertwist effects suitable.

Surprisingly, it was found that the addition of compounds of formula I provides liquid crystalline phases, all meet the above criteria perfectly.

With the provision of the compounds of formula I is also quite generally the range of liquid crystalline Substances that differ in various application Aspects for the production of nematic Mixtures are suitable, considerably widened.  

The compounds of the formula I have a broad Scope of application. Depending on the selection of the Substituents may use these compounds as base materials serve, from which liquid crystalline phases for are composed predominantly; but it can also compounds of the formula I liquid-crystalline base materials be added from other classes of compounds, for example, the dielectric and / or optical Anisotropy of such a dielectric to optimize. The Compounds of the formula I are also suitable as intermediates for the manufacture of other substances which are known as Use components of liquid-crystalline phases.

The compounds of the formula I are colorless in the pure state and form liquid crystalline mesophases in a the electro-optical use conveniently located temperature range. They are chemical, thermal and against light very stable.

The invention thus relates to the compounds of Formula I and the use of these compounds as components liquid crystalline phases. Furthermore, subject the invention liquid-crystalline phases with a Content of at least one compound of the formula I and Liquid crystal display elements containing such phases.

Above and below, R, m , Y, Ph, L¹, L², L³, L⁴ and X have the indicated meaning, unless expressly stated otherwise.

The compounds of the formula I accordingly comprise Compounds of the following subformulae:

wherein X, Ph and R have the meaning given, and Y is O or a single bond.

wherein X, Ph and R have the meaning given.

wherein X, Ph and R have the meaning given, and Y is O or a single bond.

In formula I and in the sub-formulas, X is preferably F, Cl, -CF₃, -OCF₃, OCHF₂, -NCS or -NO₂. Ph-X is preferably 3-fluoro-4-X-phenyl or 3,5-difluoro-4- X-phenyl. Particularly preferred meanings are 2-fluoro 4-cyanophenyl, 3-fluoro-4-cyanophenyl, 3,5-difluoro-4-cyanophenyl, 2-fluoro-4-isothiocyanatophenyl, 3-fluoro-4-iso thiocyanatophenyl and 3,5-difluoro-4-isothiocyanatophenyl.

Also particularly preferred are compounds in which X is -CN or -NCS and one of the radicals L¹, L², L³ and L⁴ F means.

Also preferred are biphenylylethanes of the formula Ib, wherein X is -CN or -NCS, as well as biphenylylethane of formula Ic, wherein X is -CN or -NCS.

Particular preference is also the compounds of Formula Id,

wherein R is methyl, ethyl or n-propyl.

If the groups R are alkyl radicals in which also a ("oxaalkyl") CH₂ group to be replaced by O atoms can, they can be straight-chain or branched. Preferably if they are straight-chain, they have 2, 3, 4, 5, 6 or 7 carbon atoms and thus mean preferably ethyl, propyl, Butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, Pentoxy, hexoxy, heptoxy, 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, furthermore methyl, octyl, nonyl, Decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, Methoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy, Tetradecoxy, pentadecoxy, 2-, 3-, 4-, 5-, 6- or 7-oxo-octyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl, 1,3-dioxabutyl (= Methoxymethoxy), 1,3-, 1,4- or 2,4-dioxapentyl, 1,3-, 1,4-, 1,5-, 2,4-, 2,5- or 3,5-dioxahexyl, 1,3-, 1,4-, 1,5, 1,6, 2,4, 2,5, 2,6, 3,5, 3,6 or 4,6-dioxaheptyl.

Particular preference is also given to alkyl radicals in which one CH₂ group by a -CH = CH group or by -CHF- is replaced.

m is preferably 1. X is preferably O, a single bond or trans-1,4-cyclohexylene; especially preferred is a single bond.

Compounds of the formula I with branched wing groups R can occasionally because of better solubility in the usual liquid-crystalline base materials of Be important, but especially as chiral dopants, if they are optically active.  

Branched groups of this kind usually contain no more than a chain branch. 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, 2-octyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 1-methyl heptoxy (= 2-octyloxy), 2-oxa-3-methylbutyl, 3-oxa-4 methylpentyl, 4-methylhexyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-Methyloctoxy, 6-methyloctanoyloxy, 5-methylheptyloxy carbonyl, 2-methylbutyryloxy, 3-methylvaleryloxy, 4- Methylhexanoyloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl.

For compounds having branched wing groups Formula I, both the optical antipodes and racemates as well as their mixtures.

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

Particularly preferred smaller groups of inventive Compounds are those of the following subformulae:

Further preferred are those of the subformulae Ia ', Ib 'and Ic':

The compounds of the formula I are known per se Methods prepared as described in the literature (eg. in the standard works such as Houben-Weyl, Methods of the Organic Chemistry, Georg Thieme Verlag, Stuttgart) are, under reaction conditions, for the said reactions are known and suitable. there You can also from known, here not closer make use of the variants mentioned.

If desired, the starting materials may also be in situ be formed, such that they are from the reaction mixture not isolated, but immediately continue to the connections the formula I implements.

 Thus, the compounds of formula I can be prepared by reacting a compound of the formula II

or a corresponding ethyne compound among the skilled person catalytically hydrogenated known conditions. In formula II, L¹, L², L³, L⁴, m, X and Y are as defined above Conditions. R is alkyl, fluoroalkyl or oxaalkyl.

The compounds of formula II are available in per se known manner to Wittig or by rear coupling corresponding styrene compounds with haloaromatics (Bromine or iodine), which are either known or in complete analogy to known compounds can be.

Leave compounds of the invention with alkenyl groups in analogy to similar known compounds by Wittig reaction, the starting materials also accessible by rear couplings.

The compounds of formula I may further by Cross-coupling according to DE-OS 36 08 502, DE-OS 36 32 410 or DE-OS 37 36 489 or by Wolff-Kishner reduction corresponding Methylene ketones are produced, in turn easily by Friedel-Crafts acylations from the corresponding arylacetic acid chlorides and corresponding Benzene or biphenyl precursors are accessible.

The liquid-crystalline phases according to the invention consist from 2 to 15, preferably 3 to 12 components, including at least one compound of the formula I. The others Ingredients are preferably selected from the nematic or nematogenic substances, in particular the known substances, from the classes of azoxybenzenes, Benzylideneanilines, biphenyls, terphenyls, phenyl or Cyclohexyl benzoates, cyclohexane-carboxylic acid phenyl or cyclohexyl esters, phenylcyclohexanes, cyclohexylbiphenyls, Cyclohexylcyclohexanes, cyclohexylnaphthalenes, 1,4-bis- cyclohexylbenzenes, 4,4'-biscyclohexylbiphenyls, phenyl-  or cyclohexylpyrimidines, phenyl- or cyclohexyl-dioxanes, Phenyl or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclo hexylethanes, optionally halogenated stilbenes, Benzylphenyl ethers and substituted cinnamic acids.

The most important as constituents of such liquid-crystalline Leave phases in question characterized by the formula IV,

R⁶-L-G-E-R⁷ IV

wherein L and E are each a carbo- or heterocyclic ring system from the 1,4-disubstituted benzene and cyclohexane rings, 4,4'-disubstituted biphenyl, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted Pyrimidine and 1,3-dioxane rings, 2,6-disubstituted Naphthalene, di- and tetrahydronaphthalene, Quinazoline and tetrahydroquinazoline formed group,

G -CH = CH- -N (O) = N- -CH = CY- -CH = N (O) - -C≡C- -CH₂-CH₂- -CO-O- -CH₂-O- -CO-S- -CH₂-S- -CH = N- -COO-Phe-COO-

or a CC single bond,
Y is halogen, preferably chlorine, or -CN, and
R⁶ and R⁷ are alkyl, alkoxy, alkanoyloxy or alkoxycarbonyloxy having up to 18, preferably up to 8 carbon atoms, or one of these radicals by CN, NC, NO₂, CF₃, F, Cl or Br.

For most of these compounds, R⁶ and R⁷ are different from each other different, one of these residues usually one Alkyl or alkoxy group. Also other variants the proposed substituents are in use. Lots Such substances or mixtures thereof are commercially available available. All these substances are known from the literature Methods available.

The phases according to the invention contain about 0.1 to 99 preferably 10 to 95% of one or more compounds of the formula I. Further preferred are inventive liquid crystalline phases containing 0.1-40, preferably 0.5-30% of one or more compounds of Formula I.

The compounds of the formula I can also be used as components smectic or chiral tilted smectic liquid crystalline Phases are used. These phases are preferably chirally tilted smectic liquid crystalline Phases whose achiral base mixture in addition to compounds of the formula I at least one other component with negative or small positive dielectric Anisotropy contains. This further component (s) of the achiral base mixture can (can) to 1 to 50%, preferably 10 to 25%, make up the base mix.

The preparation of the phases according to the invention takes place in in the usual way. In general, the components are dissolved in each other, useful at elevated temperature.

By suitable additives, the liquid-crystalline Phases according to the invention are modified so that they in all previously known types of liquid crystal display elements can be used.  

Such additives are known in the art and in the Literature described in detail. For example, you can Conducting salts, preferably ethyldimethyldodecylammonium 4-hexyloxybenzoate, tetrabutylammonium tetraphenylboranate or complex salts of crown ethers (see, for example, I. Haller et al., Mol. Cryst. Liq. Cryst. Volume 24, pages 249-258 (1973)) to improve the conductivity, dichroic 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. Such substances are z. B. in DE-OS 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430, 28 53 728 and 29 02 177 described.

The following examples are intended to illustrate the invention, without limiting it. F. = melting point, K. = clearing point. Above and below, percentages are by weight; All temperatures are in degrees Celsius. "Usual processing" means: you give water added, extracted with methylene chloride, separated, dried the organic phase, evaporated and purified Product by crystallization and / or chromatography.

example 1

A solution of 9.5 g of 1- (p-fluorophenyl) -2- (4'-n-pentyl) biphenyl-4-yl) -ethane [obtained by Heck coupling of 4-fluorostyrene with 4-bromo-4'-n-pentylbiphenyl] in 100 ml Tetrahydrofuran is in the presence of Pd / C until completion hydrogenated the H intake. After usual work-up to give 1- (p-fluorophenyl) -2- (4'-n-pentylbiphenyl) 4-yl) -ethane, mp 60 °, K. 109 °.  

Analog are produced:

1- (p-fluorophenyl) -2- (4'-n-propylbiphenyl-4-yl) ethane
1- (p-chlorophenyl) -2- (4'-n-propylbiphenyl-4-yl) ethane
1- (3-Fluoro-4-chlorophenyl) -2- (4'-n-propyl-biphenyl-4-yl) -ethane
1- (p-Chlorophenyl) -2- (4'-n-propyl-2'-fluorobiphenyl-4-yl) ethane

Claims (18)

1. biphenylylethanes of the formula I, wherein
R is alkyl, fluoroalkyl, alkenyl or oxaalkyl,
m 1 or 2,
Y, S, CO-O, O-CO, O-CO-O, a single bond or, in the case of m = 1, also trans-1,4-cyclohexylene,
Ph in each case identical or different radicals selected from the group consisting of 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene and 3,5-difluoro-1,4-phenylene,
L¹, L², L⁴ are each H or one of these radicals is also F,
L⁴H or F and
X is F, Cl, -CF₃, -CN, -OCF₃, -OCHF₂, -NCS or -NO₂, with the proviso that

• a) in the case of X = -CN Y trans-1,4-cyclohexylene or m = 2 and / or Ph-X 2-fluoro-4-cyanophenyl, 3-fluoro-4-cyanophenyl or 3,5-difluoro-4- cyanophenyl and / or one or two of the radicals L¹, L², L³ and L⁴ is F and
• b) in the case of X = NCS, Y = trans-1,4-cyclohexylene or m = 2 and / or Ph-X 2-fluoro-4-isothiocyanatophenyl, 3-fluoro-4-isothiocyanatophenyl or 3,5-difluoro-4 -isothiocyanatophenyl and / or one or two of the radicals L¹, L², L³ and L⁴ F and / or -YR straight-chain alkyl having up to 3 carbon atoms.

2. biphenylylethanes according to claim 1, characterized by the formula Ia, wherein X, Ph and R have the meaning given and represents YO or a single bond. 3. biphenylylethane according to claim 1, characterized by the formula Ib, wherein X, Ph and R have the meaning given. 4. biphenylylethane according to claim 1, characterized by the formula Ic, wherein X, Ph and R have the meaning given and represents YO or a single bond. 5. Biphenylylethane according to at least one of the claims 1 to 4, characterized in that X is F, Cl, -CF₃, -OCF₃, -OCHF₂-, -NCS or -NO₂ means. 6. biphenylylethane according to claim 5, characterized in that Ph-X 3-fluoro-4-X-phenyl or 3,5-difluoro- 4-X-phenyl. 7. Biphenylylethane according to at least one of the claims 1 to 4, characterized in that Ph-X 2-fluoro-4- cyanophenyl, 3-fluoro-4-cyanophenyl or 3,5-difluoro-4 Cyanophenyl means. 8. biphenylylethane according to claim 3, characterized that X is -CN. 9. biphenylylethanes according to claim 4, characterized that X is -CN. 10. biphenylylethane according to claim 1, characterized that X is -CN and one of the radicals L¹, L², L³ and L⁴ F means.   11. Biphenylylethane according to at least one of the claims 1 to 4, characterized in that Ph-X 2-fluoro-4- isothiocyanatophenyl, 3-fluoro-4-isothiocyanatophenyl or 3,5-difluoro-4-isothiocyanatophenyl. 12. biphenylylethane according to claim 3, characterized that X means -NCS. 13. Biphenylylethane according to claim 4, characterized in that that X means -NCS. 14. biphenylylethane according to claim 1, characterized that X is -NCS and one of the radicals L¹, L², L³ and L⁴ F means. 15. biphenylylethane according to claim 1, characterized by the formula Id wherein R is methyl, ethyl or n-propyl. 16. Use of the compounds of the formula I according to claim 1 as components of liquid crystalline phases. 17. Liquid-crystalline phase with at least two liquid-crystalline Components, characterized in that it contains at least one compound of the formula I. 18. Liquid crystal display element, characterized in that it is a liquid-crystalline phase according to claim 17 contains.