JPS6264865A - Anthraquinone compound and liquid crystal composition containing the same - Google Patents

Abstract

NEW MATERIAL:The titled compds. of formula I [wherein R<1> is a group of formula II or III; R<2> is H, a group of formula IV-V, (cyclo)alkyl, alkoxy, halogen, aryl, trans-4-alkylcyclohexyl; R<3> is H, alkyl; R<4> and R<6> each are (cyclo) alkyl, a group of formula VI, aryl, trans-4-alkylcyclohexyl, R<5> and R<7> each are alkyl; l and n each are 1-5; m is 0 or 1]. EXAMPLE:Compds. of formula VII. USE:Anthraquinone compds., when dissolved in a crystal liquid, exhibiting a high dichroic ratio and yellow to yellowish orange color. PREPARATION:A compd. of formula VIII is reacted with a compd. of formula IX in the presence of an (org.) acid acceptor (e.g. K2CO3) in a solvent (e.g. N,N-dimethylformamide) at 50-200 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel anthraquinone compound and a liquid crystal composition containing the compound.

[Conventional technology]

It has been known that a liquid crystal composition made by dissolving a dye compound in liquid crystal is interposed between two opposing electrodes, and color display is performed by utilizing the guest-host effect between the dye compound and the liquid crystal. .

The dye compound used in such a liquid crystal composition is particularly required to have properties such as a high dichroic ratio and high solubility in the liquid crystal.

The present inventors conducted studies focusing on anthraquinone compounds in order to provide a dye compound having the above properties and exhibiting a yellow to yellow-orange hue.

Anthraquinone compounds that exhibit a yellow to yellow-orange hue are
It is known that it is used in liquid crystal compositions (JP-A No. 57-747, JP-A No. 6, etc.).

However, studies conducted by the present inventors have revealed that conventional anthraquinone compounds do not necessarily satisfy the properties required of dye compounds used in liquid crystal compositions as described above.

[Problem that the invention seeks to solve]

Therefore, an object of the present invention is to provide an anthraquinone metal compound that exhibits a high dichroic ratio and good solubility in liquid crystals, and to provide a liquid crystal composition that can provide good color display. It is.

[Means for solving problems]

The present invention relates to a group represented by the general formula [I] [wherein R1 is a group represented by -coo%i'' or -
Indicates a group represented by CH-CH-COOR', R2 is a hydrogen atom, a group represented by +CH-CM sound COOR', an alkyl group, an alkoxy group, -o+cH, cH, o
+-u? A group represented by, a halogen atom, an aryl group,
Cycloalkyl group represents a trans-+-furkylcyclohexyl group, Bj represents a hydrogen atom or an alkyl group, R4 represents an alkyl group, % OH, CH, OV-
R' represents a group represented by te, an aryl group, a cycloalkyl group; RI and R7 represent an alkyl group; R6 represents an alkyl group; +CH, CH2O) J a group represented by R', an aryl group, cycloalkyl group - 1 digit) represents a lansudar alkylcyclohexyl group, 1 and n represent an integer of iys, and m represents O or l. ] The gist thereof is an anthraquinone compound represented by the following and a liquid crystal composition containing the compound.

The anthraquinone compound of the present invention has the general formula [I]
It is expressed as

In the formula, examples of the alkyl group represented by Bt, HA, H4, R3, R6, R7, and the like include alkyl groups having a carbon number of l to it. The aryl group represented by RζR4 and R6 includes daralkyl (for example, carbon number 1
~13 alkyl) phenyl group, der alkoxy (e.g., alkoxy with carbon number /-/J) phenyl group, biphenyl group, cyclohexylphenyl group, transder alkyl (e.g., alkyl with carbon number /-/, ?) cyclohexyl Examples of the cycloalkyl group include a cyclohexyl group, a cyclopentyl group, and a cycloheptyl group.
For example, a cyclohexyl group (alkyl having 1 to 3 carbon atoms) may be mentioned.

Examples of the alkoxy group represented by R2 include alkoxy groups having a carbon number of /-/g, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and the like.

In addition, the above-mentioned alkyl group or alkoxy group having 3 or more carbon atoms may be linear or branched.

More preferably R2, R1, R4, R5, R6 and R? Examples of the alkyl group represented by the above include alkyl groups having 1 to 5 carbon atoms, and examples of the aryl groups represented by R1, R4, and R6 include alkylphenyl groups, alkoxyphenyl groups, and biphenyl groups each having 1 to 3 carbon atoms. , cyclohexylphenyl group, trans-alkyl (e.g. alkyl of carbon az Examples include 7-alkyl (for example, alkyl having 1 to 1 g carbon atoms) and cyclohexyl group.

The number of carbon atoms in the alkoxy group represented by R2 is t.
Examples include the alkoxy group of yg.

The anthraquinone compound represented by the general formula [1] is synthesized, for example, by the following method.

I O [■] [Oni] [11] (R1 and R2 in the above general formulas [I] to [ID have the same meanings as above.) The above reaction is performed using N,N-dimethylformamide, acetamide, and N-methylpyrrolidone. An acid binder such as an alkali metal carbonate such as potassium carbonate or sodium carbonate, an alkali hydroxide such as sodium hydroxide or potassium hydroxide, or acetic acid. In the presence of an acetate group such as potassium or sodium acetate, or an organic acid binder such as triethylamine, 5θ = 200°C, preferably gO ~ 15
It can be carried out under a temperature condition of 0 [.

The nematic liquid crystal used in the present invention can be selected from a wide range as long as it exhibits a nematic state within the operating temperature range.

Further, by adding an optically active substance to be described later to such a nematic liquid crystal, it can be made to take a cholesteric state. Examples of nematic liquid crystals include the substances shown in Table 1 below, or derivatives thereof.

Table 1-12= In the above Table 1, R' represents an alkyl group or an alkoxy group, and X represents an alkyl group, an alkoxy group, a nitro group, a cyano group, or a halogen atom.

All of the liquid crystals in Table 1 have positive dielectric anisotropy, but the known ester-based, azoxy-based, azo-based liquid crystals, which have negative dielectric anisotropy,
A Schiff-based, pyrimidine-based, diester-based, or biphenyl ester-based liquid crystal can also be mixed with a liquid crystal having positive dielectric anisotropy to form a positive liquid crystal as a whole.

Furthermore, even a liquid crystal with negative dielectric anisotropy can be used as is if an appropriate element configuration and driving method are used.

The host liquid crystal material used in the present invention may be any of the liquid crystals shown in Table 1 or a mixture thereof, but a mixture of the following types of liquid crystals is sold by Merck & Co. under the trade name ZLI-//3:1. Br1tish Drug House
A liquid crystal sold by E Company under the black market name E-7 is particularly useful in the present invention.

Examples of optically active substances used in the present invention include chiral nematic compounds such as -1-methylbutyl group, 3-methylbutoxy group, 3-methylpentyl/14,3-methylpentoxy group, goomethylhexyl group, goomethylhexitoxy group, etc. There are compounds in which optically active groups are introduced into nematic liquid crystals. Also, JP-A-57-11! ! ;'L shown in No. Il-
- Alcohol derivatives such as menthol and d-borneol, d-camphor, ketone derivatives such as 3-methylcyclohexane, carboxylic acid derivatives such as d-citronellaic acid and l-camphoric acid, aldehyde derivatives such as d-citronellal, d-linonene Optically active substances such as alkene derivatives such as, other amines, amides, and nitrile derivatives can be used.

As an element for performing liquid crystal display using the liquid crystal of the present invention, a known liquid crystal display element can be used. That is,
In general, transparent electrodes of any pattern are provided on two glass substrates, at least one of which is transparent, and the device is placed so that the two glass substrates are parallel to each other with a suitable spacer interposed so that the electrode surfaces face each other. The configured one is used.

In this case, the spacer determines the gap between the elements. The element gap is 3 to io.

From a practical standpoint, it is preferable that the thickness is 5 to Sθμm in μm and %.

〔Effect of the invention〕

The anthraquinone compound of the present invention has a linking group -CH-CH
By introducing a -Coo- or transcyclohexylcarboxylic acid ester group, it exhibits good solubility in liquid crystals, and liquid crystal compositions containing this compound have a high dichroic ratio, making it possible to display clear colors. be.

〔Example〕

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

In addition, in the following examples, () represents the trans isomer of a cyclohexyl group.

Further, the order parameter indicating the dichroic ratio will be explained below.The order parameter S of the color chart compound can be experimentally determined from the following equation.

Here, A/ and A are the absorbance of the dye with respect to light polarized parallel and perpendicular to the alignment direction of the liquid crystal, respectively.

Specifically, the order parameter S is a value indicating the display contrast of a guest-host type liquid crystal element, and theoretically, as this value approaches l, the degree of residual color in white areas decreases.
A bright and clear display with high contrast is possible.

Example 1 p-n-butylthiophenol/! in N-methylpyrrolidone (NMP) solution -○- in which potassium hydroxide SO■ was dissolved Om9 and the compound qoo represented by the following structural formula
m9 was added and stirred for 3 hours at ios~11Q'Q. After lowering the temperature to around SOC, the reaction solution was discharged into a 3Q% saline bath solution, and the precipitated crystals were filtered and dried, and silica gel (
Impurities were separated by column chromatography using C-200 (manufactured by Wako Pure Chemical Industries, Ltd., trade name) as a carrier and chloroform as a separation solvent, and 150 my of anthraquinone compound of the present invention represented by the following structural formula was obtained.
I got it. This compound is /994'~kooko. It showed a melting point of 5°C.

The obtained compound (dye) was added to the above-mentioned phenylcyclohexane mixed liquid crystal ZLI-1/3,1, heated to 70C or higher to turn the liquid crystal into an isotropic liquid, stirred well, and then left to cool. This process was repeated to dissolve and prepare a liquid crystal composition.

The above-mentioned liquid crystal composition prepared in this manner was applied to an inter-substrate gap consisting of two glass substrates having a transparent electrode and a homogeneous alignment treatment performed by coating and curing a polyamide resin on the surface in contact with the liquid crystal and then rubbing it. It was encapsulated in an Opm device. In the element subjected to the alignment treatment, the liquid crystal was in a homogeneous alignment state when no voltage was applied, and the dye molecules were also aligned in the same manner according to the host liquid crystal.

The absorption spectrum of the guest-host device thus prepared was measured using light polarized parallel to and perpendicular to the orientation direction of the liquid crystal molecules, respectively.
The maximum absorption wavelength of the dye for each of these polarized lights was determined.

In determining the absorbance of the dye, corrections were made for absorption by the host liquid crystal and glass substrate and reflection loss of the element.

Also, using A/ and A soil for each polarization, the above formula The order parameter S was directly calculated from

The above results are shown in Table 2 below.

Example 1 Into an NMP solution in which potassium hydroxide sθ~ was dissolved, -t-butylthiophenol lSθ■ and a compound 1IooIn9 represented by the following structural formula were added, and 100~/
0! ; Stirred at C for 1 hour. After lowering the temperature to around SO ℃, the reaction solution was discharged into a 30% saline solution, and the precipitated crystals were filtered and dried, and then subjected to column chromatography using silica gel C-2θO as a carrier and chloroform as a separation solvent. Impurities are separated and purified to produce anthraquinone compound 3301n of the present invention represented by the following structural formula.
I got a 9. This compound is Koda S, 0-24'6. ．． showed the melting point in °C.

This compound (dye) was added to the above-mentioned phenylcyclohexane mixed liquid crystal ZLI-//, according to the method described in Example 1.
A molten crystal composition was prepared.

In the above liquid crystal composition, the liquid crystal assumes a homogeneous alignment state when no voltage is applied in the element subjected to the alignment treatment described in Example//, and the dye molecules also assume a similar alignment according to the host liquid crystal.

Further, according to the method described in Example 1, the maximum absorption wavelength of the dye and the value of the order parameter S for each polarized light were calculated.

The above results are shown in Table 2 below.

Example 3 Potassium hydroxide θ, 1I9- in NMP solution 1,j-
Dichloroanthraquinone o, s 1il- and a compound represented by the following structural formula /, 3 / f were added and S was heated at 120°C.
Stir for hours. After lowering the temperature to around 0°C, the reaction solution was discharged into a 3θ salt aqueous solution, and the precipitated crystals were filtered and dried, and impurities were removed by column chromatography using silica gel C-200 as a carrier and chloroform as a separation solvent. was separated and separated to obtain 2gO2 of the anthraquinone compound of the present invention represented by the following structural formula. This compound is! ; /, 0-2! /,! i℃
It showed a melting point of

This compound (dye) was prepared according to the method described in Example 1 to form the above-mentioned phenylcyclohexane mixed liquid crystal ZL! -//3
A liquid crystal composition 'ff: was prepared.

In the above liquid crystal composition, the liquid crystal was in a homogeneous alignment state when no voltage was applied in the element subjected to the alignment treatment described in Example 1, and the dye molecules were also aligned in the same manner according to the host liquid crystal. .

Further, according to the method described in Example 1, the maximum absorption wavelength of the dye and the value of order parameter 8 for each polarized light were calculated.

The above results are shown in Table 2 below.

Examples 1I to 32 The anthraquinone compounds of the present invention shown in Table 1 below were produced in the same manner as in Examples 7 to 3.

In addition, a liquid crystal composition was prepared using the obtained compound (dye) in the same manner as in Example 1, and the maximum absorption wavelength and order parameter (S) of the dye in the obtained liquid crystal composition were measured. In addition, the results were shown in the second article.

In Table 1, the compound 2 shown in Table 1 is trans-cyclo Example 33 in an NMP solution of potassium hydroxide 4Lo■ was added, and the mixture was stirred at 120 to 130°C for S hours. . After lowering the temperature to around SO ℃, it was discharged into a 30% saline solution, the precipitated crystals were filtered and dried, and impurities were purified by column chromatography using silica gel C-coOθ as a carrier and chloroform as a separation solvent. The following structural formula ts;orrv) was obtained. This compound is lza3. g ~I
It showed a melting point of 0°C.

Using the obtained compound (dye), according to the method described in Example 1, the above-mentioned phenylcyclohexane-based mixed liquid crystal Z
LI-//3 was dissolved to prepare a liquid crystal composition.

In the liquid crystal composition, the liquid crystal was in a homogeneous alignment state when no voltage was applied in the element subjected to the alignment treatment described in Example 1, and the dye molecules were also aligned in the same manner according to the host liquid crystal.

Further, according to the method described in Example 1, the maximum absorption wavelength of the dye and the value of order parameter 8 for each polarized light were calculated.

The above results are shown in Table 3 below.

Example j4' P-t-butylthiophenol θ~ and compound 60 shown by the following structural formula were added to an NMP solution θ in which potassium hydroxide io~ was dissolved/S at Jθ°C to 130°C. Stir for an hour. After lowering the temperature to about SO°C, it is discharged into a 30% saline solution. The precipitated crystals were filtered and dried, and impurities were separated and purified by column chromatography using silica gel c-s, oo as a carrier and chloroform as a separation solvent to obtain the anthraquinone compound 30 of the present invention represented by the following structural formula. I got it. This compound is 2co9.5-co,? / indicates the melting point of OC.

Using this compound (dye) and following the method described in Example 33, the above-mentioned phenylcyclohexane-based mixed liquid crystal ZLI
-113- to prepare a liquid crystal composition.

In the above liquid crystal composition, the liquid crystal was in a homogeneous alignment state when no voltage was applied in the element subjected to the alignment treatment described in Example 1, and the dye molecules were also in a similar alignment according to the post-liquid crystal. .

In addition, the maximum absorption wavelength of the dye and the value of the order parameter S for each polarized light were calculated according to the method described in Examples.

The above results are shown in Table 3 below.

Examples 35-6 Examples 33-34! Anthraquinone thread compounds of the present invention shown in Table 3 below were produced in the same manner as above.

In addition, a liquid crystal composition was prepared using the obtained compound (dye) in the same manner as in Example 1, and the maximum absorption wavelength and order parameter (8) of the dye in the obtained liquid crystal composition were measured. The results are also shown in Table 3.

In addition, in Table 3, ( indicates trans-cyclohexyl.

Claims (2)

[Claims] (1) General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] [In the formula, R^1 is a group represented by ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or -CH= -CH-COOR^4, R^2 is a hydrogen atom, -(CH=CH)-_mCOO
A group represented by R^6, an alkyl group, an alkoxy group, -
Represents a group represented by O-(CH_2CH_2O)-_nR^7, a halogen atom, an aryl group, a cycloalkyl group, or a trans-4-alkylcyclohexyl group, and R
^3 represents a hydrogen atom or an alkyl group, and R^4 is
Indicates an alkyl group, a group represented by -(CH_2CH_2O)-_lR^5, an aryl group, a cycloalkyl group, or a trans-4-alkylcyclohexyl group, and R^5
and R^7 represents an alkyl group, R^6 is an alkyl group, a group represented by -(CH_2CH_2O)-_lR^5, an aryl group, a cycloalkyl group, or a trans-4
- represents an alkylcyclohexyl group, l and n are 1 to
It represents an integer of 5, and m represents 0 or 1. ]An anthraquinone compound represented by (2) General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [I] [In the formula, R^1 is a group represented by ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or -CH= Indicates a group represented by CH-COOR^4, R^2 is a hydrogen atom, -(CH=CH)-_mCOOR
Group represented by ^6, alkyl group, alkoxy group, -O
-(CH_2CH_2O)-_nRepresents a group represented by R^7, a halogen atom, an aryl group, a cycloalkyl group, or a trans-4-alkylcyclohexyl group, R^
3 represents a hydrogen atom or an alkyl group, R^4 represents an alkyl group, a group represented by -(CH_2CH_2O)-_lR^5, an aryl group, a cycloalkyl group, or a trans-4-alkylcyclohexyl group; ^5 and R^7 represent an alkyl group, R^6 is an alkyl group,
-(CH_2CH_2O)-_lR^5 group, aryl group, cycloalkyl group or trans-4-
Indicates an alkylcyclohexyl group, l and n are 1 to 5
m represents an integer of 0 or 1. ] A liquid crystal composition containing an anthraquinone compound represented by: