JPS6281354A - Antipodal phenol ester of mesogenic carboxylic acid and use as doping agent in liquid crystal phase - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The characteristics of electro-optic effects used in liquid crystal displays generally vary with temperature. This can lead to difficulties that can undesirably limit the operating temperature, especially when operating in various ways. In the case of various electro-optical effects, it is possible to add chiral compounds to nematic liquid crystals. The temperature dependence of the electro-optical properties can be advantageously influenced by the effect of temperature on the pitch of the cholesteric helical structure, which occurs due to the effects of cholesteric nematics, phase transition effects, twisted nematics, etc. (twi
sted nesatic)-cell and the recently proposed SBB “supertorsional birefringence effect”
ted birefringence effect)
1 will have a beneficial effect. A common known chiral dopant (dopan L) generally causes pitch to increase with increasing temperature. Thus, doping agents have already recently been disclosed which do not exhibit these often undesired effects.

German Patent No. 2.827.471 (U.S. Pat. No. 4.264.148) teaches that two different chiral doping agents are added to the omatic-carrying material. is known, in which one type of chiral doping agent produces a right-handed twist and the other a left-handed twist. Although pinch reduction is certainly achieved with such doping agents, in order to achieve such an effect relatively high overall concentrations are required, to the extent that other material parameters are negatively affected.

German Patent Application No. 3,333,677 describes, inter alia, a compound consisting of a chiral butanediol (2,3) and a mesogenic carboxylic acid, when used individually as a doping agent in the liquid-crystalline phase. discloses reaction products (esters) with which optimization of temperature compensation can be easily achieved. However, the known esters have a twisting capacity that is often too low for specific applications.

According to the description of this German patent application, the "p" c-product, which corresponds to the inverse value of the torsional capacity, is 9.2 to 11.
Up to 6μm・wt%.

The task of the present invention was therefore to find new compounds which, when used as doping agents in the liquid-crystalline phase, achieve an optimization of the temperature compensation and a concomitant high torsion of the helical structure even in relatively low composition amounts. .

The invention starts from known esters consisting of chiral compounds having at least two OH groups and at least one mesogenic carboxylic acid. The compound of the present invention has the general formula (I) [wherein XI is 0-11 or 0-CO
-(C+"'C+t)7/L'kill group and x2 is 0-MC or xl and x2 independently of each other mean 0-MC, where MC excludes the OH group The general formula N) includes the R- and S-configurations.

Another means for solving the problems of the present invention is to provide a twisting liquid crystal phase containing at least one chiral compound, in which at least one compound represented by the general formula (I) or phenol is used as the chiral compound. The above torsional liquid crystal phase is characterized by containing a phenol ester substituted in the aromatic moiety (corresponding to the above general formula (I) as an unsubstituted basic molecule). The term "twisted liquid crystalline phase" means a nematic phase, a cholesteric phase, a "tilted" smectic phase, especially a smectic C (SC or 5ac) phase.

The torsional liquid-crystalline phase according to the invention consists of 2 to 20, in particular 2 to 15, components, among which at least one chiral doping agent according to the invention is included. The other components are advantageously selected from known compounds which give rise to nematic, cholesteric and/or graded smectic phases'. These include, for example, Schiff bases, biphenyls, terphenyls, phenylcyclohexanes, cyclohexylbiphenyls, pyrimidines, cinnamic acid esters, cholesterin esters, p-alkylbenzoic acids, various terminally polar bridges, polynuclear There is an ester. - The commercially available liquid crystal phase already has a
It exists as a mixture of various components, at least one of which is mesogenic, i.e. gives rise to a liquid crystalline phase as a compound in an induced state or in a mixed state with certain co-components.
ropic (clearing point > melting temperature) or monotropic (clearing point > melting temperature)
mesophase formation is expected].

With newly developed compounds as dopants, it has already been possible to achieve high torsions in the liquid-crystalline phase with small amounts of dopants. In this case, some compounds still have essentially free pitch under temperature changes. That is, the increase or decrease in pitch is generally
It is in the range of χ to lχ. The product p-c (p=pitch of the resulting helical structure (μa+), concentration (weight) of the C-chiral doping agent, especially when XI and x2 are 0-11c
less than 5, especially 0.5
~4. These materials are also used in thermotopography or in the "blue phase" (= e.g. 800 nm).
relatively small pitch cholesteric system)
It can also be used in In general, monoesterified compounds produce a different direction of helical rotation than diesterified compounds (negative versus positive values), but under special conditions helical reversal also occurs in the case of diesters, which This is especially true in the case of the diesters which are XI.0-Co-(C, ~C1□)alkyl group and XZ.0-MC.

Among the compounds of general formula ([), the residue MC (general formula (I)
Particular preference is given to those in which 1) has the following meanings: R-(A'-), -(B-). (A'-)-a CO(
n) [In the formula, R is a straight-chain or branched alkyl group having 1 to 12 carbon atoms □ One or two non-adjacent C11 □- groups may be replaced by oxygen atoms. In the case of □ or nl・1, F, CA, Br or CN may be used, and AI, A2 are 1.4-
Phenylene, pyrimidine-2,5-diyl, C4-cyclohexylene, 1,3-dioxane-2,5-diyl,
1,3-dithiane-2,5-diyl or 1,4-bicyclo(2°2.2)octylene, these groups having P, (j!, Br, CN and/or 1 carbon atom -12 alkyl group (in some cases, one or two non-adjacent CH2- groups may be replaced by an oxygen atom), and B is C0-010-CO1C11
□-CH2,0CH2, C) 1.0, CII=N.

N, CH, N, N or N (O)・N, n1,
n2 and n3 are O, l or 2 independently of each other, with n1 and n3 not being 0 at the same time. ] It has the meaning expressed as follows.

Particularly preferred compounds are those in which the symbols have the following meanings: R is a straight-chain alkyl group having from 4 to IO carbon atoms;
In this case, one C+t1~ group may be replaced by an oxygen atom, and A1 and A2 are unsubstituted 1.4-phenylene or 1.4-cyclohexylene independently of each other, and B is C0- 01O-CO, and n1=
1, n2=0 or 1 and n3=1 or 2 and xl and x2 are 0-MC.

The liquid crystal phase generally contains 0.01 to 70% of the doping agent of the present invention.
Weight 2, especially 0.05 to 50 weight 2 is contained.

I of 1s+a+offi in taba dimethylformamide?
10-40 mg of dimethylaminopyridine and 1°5 of mesogenic carboxylic acid are added to the solution of -1,1''-bi-2-naphthol with stirring.

At a temperature of 0°C 1.5 m+ioβ of dicyclohexylcarbodiimide was added and at this temperature 10
Stir for a minute and then at room temperature for 20 hours. The precipitated urea is filtered off, the filtrate is concentrated under reduced pressure and the residue is dissolved in methylene chloride. After filtration if necessary, the organic solvent is evaporated and the residue is chromatographically analyzed using silica gel (the structure of the compound is confirmed by spectroscopic data and elemental analysis).

4-(4-n~hexyloxy-benzoyloxy)-
R-1,L'-bi-2-naphthol diester 4-(4-n~hexyloxy-benzoyloxy)- of benzoic acid
The R-1,1'-bi-2-naphthol monoester compound (I) of benzoic acid has a melting point of -°C and a twisting capacity (p
−c) is 1°9 to 2 at 10 to 100°C.
．． Changes to 2. Compound (2) has a melting point of 128°C and the twisting capacity varies from -6 to -9. The torsion capacity was measured using a commercially available nematic wide range mixture with a clearing point of 104°C.
e Aktiengesellschaft (Basel/Switzerland) in "RO-T 404" □.

4-(trans-4-n-heptyl-cyclohexyl)
-R-1,1'-bi-2-naphthol diester of benzoic acid To 10 mmol of mesogenic 4-(trans-4-〇-hebutyl-(cyclohexyl)-benzoic acid, 100
Add 100I1 of SOC12. 5 drops of pyridine are added and the reaction mixture is heated under reflux for 2 hours.

Excess soc x 2 is removed by evaporation. The resulting acid chloride is dissolved in pyridine. Optical activity 1. The l-bi-2-naphthol is slowly metered into this solution, after which the reaction mixture is heated under reflux for 20 hours with the addition of a spatula tip of dimethylaminopyridine. The mixture is filtered, the solution is evaporated and purified on silica gel. Analysis data (elemental analysis, NMR
-spectrum, IR-spectrum), the product after recrystallization corresponds to the above formula (3).

The following compound (4) is also synthesized in the same manner.

R- of 4'-n-pentyl-4-diphenylcarboxylic acid
Compound (3) was added to the 1,1"-bi-2-naphthol diester nematic mixture "RO-TN 404".
and (4), and for comparison, compounds (X) and (Y) are added; these comparative compounds are BDH (Brit
ish Drug House), Po 1 (Po.

le) Commercially available chiral doping agent “CB1” for (GB)
5'' and E, a commercially available chiral doping agent '5811° from Merck, Darmstadt (DE).Then, the twist in this liquid crystal phase (μm·weight X)(·p- c)-
The temperature dependence of the condition and pitch (Iχ./) at a temperature of 25° C. is measured.

It is carried out as described in Examples 1 and 2, but the acid components are changed. In Example 9, in addition to the customary mesogenic acid components, (C2-C,,)alkanoic acids are used in the reaction.

4°-trans-〇-pentyl-cyclohexyl-4-
R-1,1'-bi-2-naphthol diester of diphenyl-carboxylic acid 4''-trans-n-benzene-cyclohexyl-4-
R-1,1'-bi-2-naphthol monoester of diphenyl-carboxylic acid 4'-n-pentyl-4-terphenyl-carboxylic acid R-1,1''-bi-2-naphthol diester 4''-〇- a-t of pentyl-4-terphenyl-carboxylic acid,
t'-Be-2-naphthol monoester 4''-trans-n-pentylcyclohexyl-4=R-1,1'-Be-2-naphthol diester compound of diphenyl-carboxylic acid and acetic acid (ethanoic acid) (5) is 139-141'
C melting point and high torsional capacity at 25°C (p-
c) is +1°38, and compound (6) is 141
It has a melting point of ~145°C and a product p'c of -5.35. The p'c values of compounds (7) and (8) are +1.58 and -5,00, respectively. Compound (9), which has a melting point of 119°C, has a p'c value of ÷185.

In the accompanying drawings, the MTP-values are illustrated as a function of temperature for the above compounds 1 to 9.

MTP-value (“molecular torsional force (s+molecular
twisting power)"): β=1/p-N
v (p pitch (ll) of the helical structure formed, Nv concentration of the chiral doping agent - o j!/s'') The compound (I) of the invention has a high MTV-value (compound 3.
4.5 and 7) which show essentially unchanged (over a certain temperature range) with increasing temperature - see Figures 1 and 3 - 0 Disubstituted similar derivatives 3 .4
．． 5 and 7, this can be observed to a lesser extent. In contrast, for monoesters 2.6 and 8, the MTV value decreases with increasing temperature.

Compound 9 shows helical inversion (see Figures 3 and 4).

[Brief explanation of drawings]

1 to 5 are graphs of the molecular torsion force (MTP-value) of the compounds obtained in the examples of the present invention in relation to temperature.

Claims (1)

[Scope of Claims] 1) An ester consisting of a chiral compound having two OH groups and at least one mesogenic carboxylic acid, which has the general formula (I) ▲Mathematical formula, chemical formula, table, etc.▼( I) [In the formula, X^1 is O-H or O-CO-(C_1~C
_1_2) is an alkyl group and X^2 is O-MC or X^1 and X^2 independently of each other mean O-MC, in which case MC is mesogenic after removing the OH group. - is a molecular residue of a monocarboxylic acid. ] The above-mentioned ester is characterized in that it is represented by the following. 2) The mesogenic carboxylic acid residue MC in X^1 and X^2 has the general formula (II) R-(A^1-)_n_1-(B-)_n_2(A^2
-)_n_3CO(II) [wherein, R has 1 to 1 carbon atoms]
2 straight-chain or branched alkyl groups, in which one or two non-adjacent CH_2 groups may be replaced by oxygen atoms, or F if n1=1;
Cl, Br or CN may be used, and A^1 and A^2 are independently 1,4-phenylene, pyrimidine-2,5-
diyl, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,3-dithiane-2,5-diyl or 1,4-bicyclo(2,2,2)octylene; These groups can be F, Cl, Br, CN and/or alkyl groups having 1 to 12 carbon atoms (optionally one or two non-adjacent CH_2- groups may be replaced by oxygen atoms). ), B is CO-O, O-CO, CH_2-CH_2, OCH
_2, CH_2O, CH=N, N=CH, N=N or N(O)=N, and n1, n2 and n3 are 0, 1 or 2 independently of each other, with n1 and n3 simultaneously being 0. isn't it. ] The ester according to claim 1, which is represented by: 3) An ester consisting of a chiral compound having two OH groups and at least one mesogenic carboxylic acid in a torsional liquid crystal phase containing at least one chiral compound and having the general formula (I ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, X^1 is O-H or O-CO-(C_1~C
_1_2) is an alkyl group and X^2 is O-MC or X^1 and X^2 independently of each other mean O-MC, where MC is a mesogenic monocarboxylic group after removal of the OH group; It is a molecular residue of an acid. ] or a phenol ester substituted in the aromatic moiety of the phenol component (
The above-mentioned twisted liquid crystalline phase is characterized in that it contains an unsubstituted basic molecule corresponding to formula (I). 4) The liquid crystal phase according to claim 3, which contains 0.01 to 70% by weight of at least one chiral compound. 5) A method for temperature compensation and high torsionality by adding at least one chiral compound in a liquid crystal display component containing a liquid crystal phase,
It is an ester whose liquid crystal phase is composed of a chiral compound having two OH groups and at least one mesogenic carboxylic acid, and has the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I) [In the formula, X ^1 is O-H or O-CO-(C_1~C
_1_2) is an alkyl group and X^2 is O-MC or X^1 and X^2 independently of each other mean O-MC, where MC is a mesogenic monocarboxylic group after removal of the OH group; It is a molecular residue of an acid. ] 0.
A process as described above, characterized in that 01 to 70% by weight of at least one ester is added.