GB2288804A - Fluorinated terphenyl derivatives and a liquid crystalline medium - Google Patents
Fluorinated terphenyl derivatives and a liquid crystalline medium Download PDFInfo
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- GB2288804A GB2288804A GB9508752A GB9508752A GB2288804A GB 2288804 A GB2288804 A GB 2288804A GB 9508752 A GB9508752 A GB 9508752A GB 9508752 A GB9508752 A GB 9508752A GB 2288804 A GB2288804 A GB 2288804A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C43/00—Ethers; Compounds having groups, groups or groups
- C07C43/02—Ethers
- C07C43/03—Ethers having all ether-oxygen atoms bound to acyclic carbon atoms
- C07C43/14—Unsaturated ethers
- C07C43/17—Unsaturated ethers containing halogen
- C07C43/174—Unsaturated ethers containing halogen containing six-membered aromatic rings
- C07C43/1742—Unsaturated ethers containing halogen containing six-membered aromatic rings with halogen atoms bound to the aromatic rings
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- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K19/00—Liquid crystal materials
- C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
- C09K19/06—Non-steroidal liquid crystal compounds
- C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
- C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
- C09K19/12—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings at least two benzene rings directly linked, e.g. biphenyls
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Abstract
Terphenyl derivatives of the formula I <IMAGE> [in which n is 1 to 5; r is 1 to 5; X is CN, F, Cl or a fluorinated alkyl or alkoxy group having 1 to 5 carbon atoms; and L<1> to L<4> are each independently H or F, with the proviso that at least one of the residues L<1> to L<4> denotes F] are useful as components of liquid-crystalline media.
Description
Terphenyl derivatives, and a liquid-crystalline medium
The invention relates to novel terphenyl derivatives of the formula 1-
in which n is 1 to 5, r is 1 to 5, X is CN, F, Cl or a fluorinated alkyl or alkoxy group havingto 5 carbon atoms and Li to L4 are each independently H or F, with the proviso that at least one of the residues L1 to L4 denotes F.
EP-A-0475254 teaches similar LC compounds having an oxaalkyl terminal group. However, there is no single specific compound disclosed which has a terphenyl core structure. In addition, the compounds which are generically covered by the claims of EP-AX475254 have a different lateral substitution pattern.
Like similar compounds, for example those disclosed in WO 90/08757, the compounds of the formula I are used as components of liquid-crystalline media, in particular for displays based on the principle of the twisted cell.
All the substances employed hitherto for this purpose have certain disadvantages, for example excessively high melting points, excessively low clear points, inadequate stability to heat, light or electrical fields, inadequate electrical resistance, in particular at high temperatures and/or under the action of UV radiation, unfavourable elastic properties for the particular application, and an excessive temperature dependence of the threshold voltage.
In particular in the case of displays of the supertwist type (STN) having twist angles of considerably more than 220 or in the case of PDLC displays having an active matrix, the materials imployed hitherto have disadvantages.
The invention had the object of finding novel liquid-crystalline compounds which are suitable as components of liquid-crystalline media, in particular for nematic media having a high optical anisotropy and simultaneously a positive dielectric anisotropy, and which do not have the disadvantages of the known compounds, or only do so to a small extent. This object has been achieved by the provision of the novel compounds of the formula I.
It has been found that the compounds of the formula I are pre-eminently suitable as components of liquid-crystalline media. They can be used, in particular, to obtain liquid-crystalline media having broad nematic ranges, excellent nematogeneity down to low temperatures, excellent chemical stability, excellent elastic properties, a pronounced high optical anisotropy with a positive dielectric anisotropy and low temperature dependence of the threshold voltage. The novel compounds also exhibit good solubility for other components of media of this type and a positive dielectric anisotropy at the same time as favourable viscosity.
The compounds of the formula I facilitate both STN displays having a steep electroptical-optical characteristic and short response times and
PDLC displays having an active matrix which have excellent long-term stability. Through a suitable choice of r and n, the threshold voltages can be considerably reduced in both types of display as well as in TN displays.
In the pure state, the compounds of the formula I are colourless and form liquid-crystalline mesophases in a temperature range which is favourable located for electro-optical use.
The invention thus relates to the compounds of the formula I and to the use of the compounds of the formula I as components of liquidcrystalline media, to liquidcrystalline media containing at least one compound of the formula I, and to electro-optical displays which contain media of this type.
Above and below, r, n, L1 to L4 and X are as defined, unless expressly stated otherwise.
In the compounds of the formula 1, the alkyl groups CnH2n+1 are preferably straight-chain. Accordingly, CnH2n+1 is preferably methyl, ethyl, n-propyl, nbutyl or n-pentyl. n is preferably 1. r is preferably 2, 3, 4 or 5 particularly preferably 2 or 3.
Compounds of the formula I containing branched alkyl groups may occasionally be important due to better solubility in the customary liquid-crystalline base materials, but in particular as chiral dopants, if they are optically active. Branched groups of this type generally contain not more than one chain branch. Preferred branched alkyl- radicals are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methylbutyl), 2-methylpentyl, 3-methylpentyl or 2-heptyl (= 1 methylhexyl).
Preferred meanings of Lt to L4 are given in the following table: L1 L2 L3 L4
(1) H H H F
(2) H H F H
(3) H F H H
(4) F H H H
(5) F H F H
(6) H F F H
X is preferably F, CI, -CF3, -OCHF2 or -OCF3. Particularly preferred is Cl.
The compounds of the formula I are prepared by methods which are known per se, such as are described in the literature (for example in the standard works, such as Houben-Weyl, Methoden der Organischen
Chemie [Methods of Organic Chemistry], Georg Thieme Verlag, Stuttgart), and in particular under reaction conditions which are known and suitable for the reactions mentioned. Variants which are known per se and are not mentioned in more detail here can also be used in this connection.
If desired, the starting materials can also be formed in situ, such that they are not isolated from the reaction mixture but are immediately reacted further to give the compounds of the formula I.
The compounds of the formula I can be prepared from I -alkyl or 1 alkoxy substitute 4-bromobenzenes as starting material. The terphenyls are for example be mode by adding appropriately 4-substituted phenyl rings to such precursors using routes which couple these rings via known phenyl boronic acids. This reaction sequence is carried out a second time with the so obtained substituted biphenyls.
The terphenyls may, for example, be prepared using general routes shown in the reactions schemes 1-3:
Scheme 1
L4 F F F X{Br+ Br + (HO,)B v BreOCH3 v 8r{;}0H DME Pd(PPh3), NaHCO3 (aq.) L* F X- OCH, BI(CH,),Br I BBr3/CH2cl2 room temperature R2OH, NaH, THF L4 L L4 OH Br }(CH2)nOR2 (CF3502)20 Mg, THF, N2 TMB t N > N, O-C L F O X (HO),B (CH2),,OR2 080-cF (HO)2B 2 ; DME. Pd(PPh3)4 UCI, Na2CO3 (aq.) L4 F X-/o 2),OR2 (R2 = C,H;2I,1) Scheme 2
Scheme 3
The liquid-crystalline media according to the invention preferably contain 2 to 40, in particular 4 to 30, components as further constituents besides one or more compounds according to the invention. These media very particularly preferably contain 7 to 25 components besides one or more compounds accoding to the invention. These further constituents are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, in particular substances from the classes of the biphenyls, terphenyls, phenyl or cyclohexyl benzoates, phenyl or cyclohexyl esters of cyclohexanecarboxylic acid, phenyl or cyclohexyl esters of cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexylcyclohexanecarboxylic acid, cyclohexylphenyl esters of benzoic acid, of cyclohexanecarboxylic acid and of cyclohexylcyclohexanecarboxylic acid, phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, cyclohexylcyclohexanes, cyclohexylcyclohexenes, cyclohexylcyclohexylcyclohexenes, 1,4-biscyclohexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, phenyl- or cyclohexylpyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclohexyldioxanes, phenyl- or cyclohexyl-l ,3-dithianes, 1 ,2-diphenylethanes, 1,2-di cyclohexylethanes, 1 -phenyl-2cyclohexylethanes, 1 -cyclohexyl-2-(4- phenylcyclohexyl)-ethanes, 1 -cyclohexyi-2-biphenyiylethanes, 1 -phenyl-2- cyclohexylphenylethanes and tolans.
The 1,4-phenylene groups in these compounds may also be fluorinated.
The most important compounds suitable as further constituents of media according to the invention can be characterized by the formulae 1, 2, 3, 4 and 5:
R'-L-E-R" 1
R'-L-COO-E-R" 2
R'-L-OOC-E-R" 3 R'-L-CH2CH2-E-R" 4 R'-L-C=-C-E-R" 5
In the formulae 1, 2, 3, 4 and 5, L and E, which may be identical or different, are in each case, independently of one another, a divalent radical from the group formed by -Phe-, -Cyc-, -Phe-Phe, -Phe-Cyc-, -Cyc-Cyc-,
Pyr-, -Dio-, -G-Phe- and -G-Cyc- and their mirror images, where Phe is unsubstituted or fluorine-substituted 1,4-phenylene, Cyc is trans-1,4-cy- clohexylene or 1 ,4-cyclohexenylene, Pyr is pyrimidine-2,5-diyl or pyridine2,5-diyl, Dio is 1,3-dioxane-2,5-diyl and G is 2-(trans-1 ,4cyclohexyl)ethyl, pyrimidine-2, 5aiyl, pyridine-2,5-diyl or 1,3-dioxane-2,5Ziyl.
One of the radicals L and E is preferably Cyc, Phe or Pyr. E is preferably
Cyc, Phe or Phe-Cyc. The media according to the invention preferably contain one or more components selected from the compounds of the formulae 1, 2, 3, 4 and 5 in which L and E are selected from the group comprising Cyc, Phe and Pyr and simultaneously one or more components selected from the compounds of the formulae 1, 2, 3, 4 and 5 in which one of the radicals L and E is selected from the group comprising Cyc, Phe and Pyr and the other radical is selected from the group comprising -Phe
Phe-, -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-, and optionally one or more components selected from the compounds of the formulae 1, 2, 3, 4 and 5 in which the radicals L and E are selected from the group comprising -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-.
In the compounds of the sub-formulae 1 a, 2a, 3a, 4a and 5a, R' and R" are in each case, independently of one another, alkyl, alkenyl, alkoxy, alkenyloxy or alkanoyloxy having up to 8 carbon atoms. In most of these compounds, R' and R" are different from one another, one of these radicals usually being alkyl. or alkenyl. In the compounds of the sub-formulae 1 b, 2b, 3b, 4b and Sb, R" is -CN, -CF3, -OCHF2, -OCF3, F, CI or -NCS; in this case, R has the meaning given for the compounds of the subformulae 1 a to Sa and is preferably alkyl or alkenyl. R" is particularly preferably selected from the group consisting of -F, Cl, CF3, -OCHF2 and -OCF3. However, other variants of the proposed substituents in the compounds of the formulae 1, 2, 3, 4 and 5 are also common. Many such substances or alternatively mixtures thereof are commercially available. All these substances can be obtained by methods which are known from the literature or analogously thereto.
Besides components from the group comprising the compounds 1 a, 2a, 3a, 4a and 5a (Group 1), the media according to the invention also preferably contain components from the group comprising the compounds 1 b, 2b, 3b, 4b and 5b (Group 2), whose proportions are preferably as follows:
Group 1: 20 to 90 %, in particular 30 to 90%, Group 2: 10 to 80 %, in particular 10 to 50 %, the sum of the proportions of the compounds according to the invention and of the compounds from Groups 1 and 2 adding up to 100 %.
The media according to the invention preferably contain 1 to 40 %, in particular preferably 5 to 30 %, of compounds according to the invention.
Further preferred media are those which contain more than 40 %, in particular 45 to 90 %, of compounds according to the invention. The media preferably contain three, four or five compounds according to the invention.
The media according to the invention are prepared in a manner which is customary per se. In general, the components are dissolved in one another, expediently at elevated temperature. By means of suitable additives, the liquid-crystalline phases can be modified in accordance with the invention in a manner such that they can be used in all types of liquid-crystal display elements which have hitherto been disclosed. Additives of this type are known to those skilled in the art and are described in detail in the literature (H. Kelker/R. Hatz, Handbook of Liquid Crystals, Verlag Chemie,
Weinheim, 1980). For example, pleochroic dyes can be added for the production of coloured guest-host systems, or substances can be added to modify the dielectric anisotropy, the viscosity and/or the orientation of the nematic phases
The examples which follow are intended to illustrate the invention without restricting it. Above and below percentages are percentages by weight; all temperatures are given in degree centigrade. "Customary work-up" means that water is added, the mixture is extracted with methylene chloride, the organic phase is separated off, dried and evaporated, and the product is purified by crystallization and/or chromatography.
The following abbreviations are used: m.p. = melting point c.p. = clearing point
K = solid crystal
N = nematic liquid crystal SA = smectic A liquid crystal 5c = smectic C liquid crystal - = isotropic liquid Example I Preparation of 4-chloro-4"-(2-oxapentyl)-2' fluoro-p-terphenyl 4-(2-oxaDentvl)bromobenzene (1) 4-Bromobenzyl alcohol (46.7 g, 0.25 mol) in tetrahydrofuran (100 ml) was added dropwise to a stirred slurry of sodium hydride (8.25 g, 0.275 mol) in tetrahydrofuran (150 ml). After addition, the reaction mixture was warmed to 50" for 1 hour and then cooled to room temperature whereupon a solution of 1-bromopropane (36.9 g, 0.3 mol) in tetrahydrofuran (40 ml) was added. The reaction mixture was stirred for 16 hours and then worked up to give 58 g of yellow oil, which was purified by column chromatography (petrol/alumina) to give 44.1 g (77 % yield) of (1).
4-(2-oxapentvl)phenviboronic acid (2) Aryl bromide (1) (22.9 g, 0.1 mol) in THF (75 ml) was added dropwise to magnesium turnings (2.64 g, 0.11 mol) in 25 ml THF, and the reaction mixture then refluxed for 1 hour. The solution of the Grignard reagent was cooled to 5 and a solution of trimethyl borate (11.9 g, 0.114 mol) in THF (10 ml) was added dropwise. After stirring for 30 minutes the reaction mixture was quenched with 100 ml 10 % hydrochloric acid and the product extracted to yield the boronic acid (2) as a viscous oil (16.9 g).
4-Chlorophenvlboronic acid (3)
This was prepared analogously to (2) from 4-bromochlorobenzene.
4-Bromo-4'-chloro-2-fluorobiphenvl (4)
Boronic acid (3) (0.4 g, 0.06 mol),1-bromo-3-fluoro-4-iodobenzene (18.0 g, 0.06 mol), sodium carbonate (6.4 g, 0.06 mol), toluene (60 ml), ethanol (15 ml), water (30 ml) and tetrakis(triphenylphosphine) palladium (0) (0.07 g, 0.1 mol%) were stirred at reflux for 72 hours. After normal workup the crude product was distilled in a Kugelrohr distillation oven collecting the fraction boiling at 150 /0.3 mm Hg. The resulting white solid (12.5 g) was then recrystallised from 25 ml methanol to give (4) (10.5 g).
4-Chloro-4''-(2-oxapentyl)-2'-fluoro-p-terphenyl (5)
Boronic acid (2) (4.3 g, 0.022 mol) and bromobiphenyl (4) (5.7 g, 0.02 mol) were reacted as above to give the terphenyl (5). The crude product was purified by column chromatography (silica/petrol/ethylacetate) and then recrystallised (ethanol/ethylacetate) to give 2.6 g.
K 58.6 SA 124.8 N 129.2 1
Example 2
Preparation of 4-chloro-4"-(3-oxapentyl)-2'-fluoro-p-terphenyl (6) 4-(3-oxapentvl)bromobenzene (7)
This was prepared analogously to (1) starting from 4-bromophenethyl aicohol and bromoethane.
4-(3-oxanentvl)nhenviboronic acid (8)
This was prepared analogously to (2) starting from aryl bromide (7).
4-Chloro-4"-(3-oxapentyl)-2'-fluoro-terphenyl (6)
This was prepared analogously to (5) from (4) and (8).
K 102.3 N 118.3 1 Example 3
Preparation of 4-Chloro-4"-(4-oxapentyi )-2'-fl uoro-p-terphenyl.
4-(4-oxaoentvl)brnmobenzene (9)
This was prepared analogously to (1) from 3-(4-bromophenyl)propan-1 -ol and iodomethane.
4-(4-oxapentyl)phenylboronic acid (10)
This was prepared analogously to (2) starting from aryl bromide (9).
4-chloro-4"-(4-oxapentyl)-2'-fluoro-p-terphenyl
This was prepared analogously to (5) from (4) and (10).
K 111.8 SA 120.0 N 151.9
Analogously prepared are the following compounds: 4-chloro-4"-(4-oxapentyl)-2',2"-difluoro-p-terphenyl
K70.3 N 93 l An 0.248 ## 13.0 Viscosity 58 cSt 4-cyano-4"-(4-oxapentyl )-2"-fluoro-p-terphenyl K 108.8 N 194.7 1
Claims (6)
- Patent Claims 1. Terphenyl derivatives of the formula Iin which n is 1 to 5, r is 1 to 5, X is CN, F, CI or a fluorinated alkyl or alkoxy group having 1 to 5 carbon atoms and L1 to L4 are each inde pendently H or F, with the proviso that at least one of the residues L to L4 denotes F.
- 2. Terphenyl derivatives according to Claim 1, characterized in that L2 or L3 denotes F.
- 3. Terphenyl derivatives according to Claim 1 or 2, characterized in that X denotes CI.
- 4. Use of the terphenyl derivatives of the formula I according to Claim 1 as components of liquid crystalline media for electro-optical displays.
- 5. Liquid-crystalline medium for electro-optical displays having at least two liquidcrystalline components characterized in that at least one component is a terphenyl derivative of the formula I according to Claim 1.
- 6. Electro-optical display based on a liquid crystal cell, characterized in that the liquiderystal cell contains a medium according to Claim 5.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP94106714 | 1994-04-29 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9508752D0 GB9508752D0 (en) | 1995-06-14 |
| GB2288804A true GB2288804A (en) | 1995-11-01 |
| GB2288804B GB2288804B (en) | 1997-12-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9508752A Expired - Fee Related GB2288804B (en) | 1994-04-29 | 1995-04-28 | Terphenyl derivatives, and a liquid-crystalline medium |
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| Country | Link |
|---|---|
| GB (1) | GB2288804B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06264059A (en) * | 1993-01-22 | 1994-09-20 | Merck Patent Gmbh | Fluoroterphenyl fluorinated with nematic liquid crystal mixture |
-
1995
- 1995-04-28 GB GB9508752A patent/GB2288804B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06264059A (en) * | 1993-01-22 | 1994-09-20 | Merck Patent Gmbh | Fluoroterphenyl fluorinated with nematic liquid crystal mixture |
Non-Patent Citations (1)
| Title |
|---|
| WPI Abstract Accession No 95-001587/01 & JP 06 264 059 A [1994] * |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9508752D0 (en) | 1995-06-14 |
| GB2288804B (en) | 1997-12-17 |
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| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20060428 |