JPH0635548B2 - Anthraquinone dye and liquid crystal composition containing the dye - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel anthraquinone dye and a liquid crystal composition containing the anthraquinone compound.

2. Description of the Related Art Conventionally, there has been known a color liquid crystal in which a liquid crystal containing a dye compound is interposed between two electrodes facing each other to perform a color display by utilizing a guest-host effect of a dye and a liquid crystal. Development of dyes is desired.

Conventionally, for example, general formula In particular A liquid crystal composition using a red anthraquinone compound represented by the formula as a dye is known (JP-A-56-55479).
Issue).

Also, the general formula In particular The blue anthraquinone compound represented by
It is known that it can be used for a host type liquid crystal display device (Japanese Patent Laid-Open No. 58-53954).

It is an object of the present invention to provide a novel anthraquinone dye and a liquid crystal composition containing an anthraquinone dye compound exhibiting a high order parameter in a liquid crystal and exhibiting an orange to cyan color.

Means for Solving the Problems The present invention has the general formula [I] [In the formula, R ^{1 to} R ⁴ represent a hydrogen atom, a hydroxy group, or an amino group which may be substituted with an alkyl group or an aryl group, and R ⁵ represents a hydrogen atom, an alkyl group, or an aryl group. , R ⁶ is a hydrogen atom or —C≡C—R ⁵
Indicates. However, R ¹ and R ² do not represent hydrogen atoms at the same time. ] The anthraquinone dye represented by the above and a liquid crystal composition containing the anthraquinone dye and a liquid crystal are summarized.

In the above general formula [I], R ^{1 to} R ⁴ are each a hydrogen atom, a hydroxy group or an amino group which may be substituted with an alkyl group or an aryl group, for example, —NHR ⁷ (R ⁷ is a carbon number of 1
~ 8 straight or branched alkyl group or 1 carbon atom
~ A phenyl group optionally substituted with an alkyl group of 8)
Indicates. However, R ¹ and R ² do not represent hydrogen atoms at the same time.
R ⁵ is a hydrogen atom, a linear or branched alkyl group having 1 to 13 carbon atoms, an aryl group, for example, (R ⁸ is a linear or branched alkyl group having 1 to 13 carbon atoms, a linear or branched alkoxy group having 1 to 13 carbon atoms, or a linear or branched alkoxy group having 1 to 13 carbon atoms. a substituted alkoxy group having 1 to 5 carbon atoms.) indicates, R ⁶ represents a hydrogen atom or a -C≡C-R ^5.

Preferable substituents and substitution positions of R ^{1 to} R ⁴ in the general formula [I] of the present invention include the following general formulas [II] to [VIII]
The thing represented by is mentioned.

The anthraquinone dye represented by the general formula [I] can be synthesized, for example, by the following known method.

That is, general formula [IX] (in the formula, R ⁹ represents a hydrogen atom or a bromine atom) and HC≡CR ⁵ are converted to cuprous iodide, bis [triphenylphosphine] palladium dichloride, triphenylphosphine. Reacting in the presence of a catalyst such as fin and tri-n-butylamine in an inert solvent such as ortho-dichlorobenzene at a temperature of 40 to 200 ° C, and optionally in a stream of an inert gas such as nitrogen gas. Can be manufactured by.

The nematic liquid crystal used in the present invention can be selected in a considerably wide range as long as it exhibits a nematic state in the operating temperature range. Further, a cholesteric state can be obtained by adding an optical rotatory substance described later to such nematic liquid crystal. Examples of nematic liquid crystals include the substances shown in Table 1 or their derivatives.

In the above table, R'is an alkyl group or an alkoxy group, X
Represents a nitro group, a cyano group, or a halogen atom.

The liquid crystals shown in Table 1 all have positive dielectric anisotropy, but have known negative dielectric anisotropy such as ester type, azoxy type, azo type,
A liquid crystal of a schiff type, a pyrimidine type, a diester type or a biphenyl ester type can be mixed with a liquid crystal having a positive dielectric anisotropy to be used as a positive liquid crystal as a whole.
Further, even a liquid crystal having a negative dielectric anisotropy can be used as it is by using an appropriate element structure and driving method.

The host liquid crystal used in the present invention may be any one of the liquid crystals shown in Table 1 or a mixture thereof. Liquid crystal sold by Merck under the trade name ZLI-1132 as a mixture of, and the following five types of liquid crystal A liquid crystal sold by British Drug House under the trade name of E-8 is particularly useful in the present invention as a mixture thereof.

As the above-mentioned optically active substance, a chiral nematic compound,
For example, 2-methylbutyl group, 3-methylbutoxy group,
3-methylpentyl group, 3-methylpentoxy group, 4-
There is a compound in which an optically active group such as a methylhexyl group or a 4-methylhexoxy group is introduced into a nematic liquid crystal. Further, alcohol derivatives such as 1-menthol and d-borneol shown in JP-A-51-45546, ketone derivatives such as d-cynole, 3-methylcyclohexane and the like, carboxylic acid derivatives such as d-citronellic acid and 1-cynoic acid, Aldehyde derivatives such as d-citronellal, alkene derivatives such as d-linonene, and other optically active substances such as amine, amide and nitrile derivatives can be used.

A known liquid crystal display device can be used as a device for displaying a liquid crystal using the liquid crystal composition of the present invention. In other words, generally, at least one transparent electrode is provided on two transparent glass substrates, and a transparent electrode having an arbitrary pattern is provided, and the two glass substrates are parallel to each other via an appropriate spacer so that the electrode surfaces face each other. Is used.
In this case, the spacer determines the gear gap of the element. The element gear is 3 to 100 μm, especially 5 to 5 μm.
0 μm is preferable from a practical viewpoint.

Action The anthraquinone dye of the present invention is a novel dye in which a specific ethynyl group is introduced to the anthraquinone dye, and such a dye is dissolved in liquid crystal to show orange to cyan color,
It also gives a bathochromic dye.

Examples Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples.

If the order parameter is explained below, the order parameter (S) of the dye compound can be experimentally obtained from the following equation.

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

The order parameter (S) is a value that specifically indicates the display contrast of the guest-host type liquid crystal element. As this value theoretically approaches 1, the residual color level in the white areas decreases and the bright contrast A large clear display is possible.

Example 1 0.7 g of 1,5-diamino-3,7-dipromo-4,8-dihydroxyanthraquinone, 0.03 g of cuprous iodide, tri-n-
1.8 g of butylamine and 0.81 g of 1-nonine are added to 50 ml of ortho-dichlorobenzene and the temperature is raised to 80 ° C. under a nitrogen stream. To this, 0.04 g of bis [triphenylphosphine] palladium dichloride and 0.32 g of triphenylphosphine are added, and the mixture is further heated and stirred for 5 hours. Orthodichlorobenzene was distilled off under reduced pressure, and the residue was separated and purified by column chromatography using silica gel as a carrier and chloroform as a separating solvent to obtain 0.32 g of an anthraquinone dye represented by the following structural formula.

The thus-obtained anthraquinone dye is added to the above-mentioned biphenyl mixed liquid crystal E-8, and the mixture is heated to 70 ° C. or higher and well stirred in a state where the liquid crystal becomes an isotropic liquid, and then left to cool. The process was repeated to dissolve the dye.

The above-prepared liquid crystal composition was provided with a transparent electrode, and a polyamide resin was applied to the surface in contact with the liquid crystal, and after hardening, lapping was performed and homogeneous alignment treatment was applied to the substrate. It was enclosed in the element of. In the element subjected to the above-mentioned alignment treatment, the liquid crystal was in a homogeneous alignment state when no voltage was applied, and the dye molecules also had the same alignment according to the host liquid crystal.

Measurement of the absorption spectrum of the guest-host device produced in this manner is carried out using light polarized parallel to the alignment direction of the liquid crystal molecules and light polarized perpendicular to the alignment direction of the liquid crystal molecules,
The maximum absorption wavelength of the dye for each of these polarized lights was determined. In determining the absorbance of the dye, the absorption by the host liquid crystal and the glass substrate and the reflection loss of the device were corrected.

Also, using A and A⊥ for each polarization, The value of the order parameter (S) was calculated from

The above results are shown in Table 2, No.1.

Example 2 In Example 1, instead of 1-nonine, an equimolar amount of 1
-Reacting using heptin, 0.35 g of anthraquinone dye represented by the following structural formula was obtained.

A guest-host device was prepared in the same manner as in Example 1 using the anthraquinone dye thus obtained,
The maximum absorption wavelength and the value of the order parameter (S) were calculated, and the results are shown in Table 2, No.2.

Example 3 In Example 1, 1,5-diamino-3,7-dipromo-4,
Instead of 8-dihydroxyanthraquinone, a molar amount of
The reaction was carried out using 1,8-diamino-3,6-dipromo-4,5-dihydroxyanthraquinone to obtain 0.41 g of an anthraquinone dye represented by the following structural formula.

A guest-host device was prepared in the same manner as in Example 1 using the anthraquinone dye thus obtained,
The maximum absorption wavelength and the value of the order parameter (S) were calculated, and the results are shown in Table 2, No. 5.

Example 4 In Example 1, 1,5-diamino-3,7-dipromo-4,
Instead of 8-dihydroxyanthraquinone, an equimolar amount of 1-amino-2,6-dipromo-4-hydroxyanthraquinone was used for the reaction to obtain 0.38 g of an anthraquinone dye represented by the following structural formula.

A guest-host device was prepared in the same manner as in Example 1 using the anthraquinone dye thus obtained,
The maximum absorption wavelength and the value of the order parameter (S) were calculated, and the results are shown in Table 2, No. 13.

Example 5 In Example 1, 1,5-diamino-3,7-dipromo-4,8
Instead of dihydroxyanthraquinone, an equimolar amount of 1-
Amino-4-hydroxyanthraquinone was used and the reaction was carried out using monochlorobenzene instead of orthodichlorobenzene to obtain 0.31 g of an anthraquinone dye represented by the following structural formula.

A guest-host device was prepared in the same manner as in Example 1 using the anthraquinone dye thus obtained,
The maximum absorption wavelength and the value of the order parameter (S) were calculated, and the results are shown in Table 2, No. 14.

Example 6 In Example 1, 1,5-diamino-3,7-dipromo-4,8
-An equimolar amount of 1,5 instead of dihydroxyanthraquinone
-Diaminoanthraquinone was used, and an equimolar amount of 1-heptin was used instead of 1-nonine to obtain 0.33 g of anthraquinone dye represented by the following structural formula.

A guest-host device was prepared in the same manner as in Example 1 using the anthraquinone dye thus obtained,
The maximum absorption wavelength and the value of the order parameter (S) were calculated, and the results are shown in Table 2, No. 22.

Example 7 In Example 6, the reaction was performed by using an equimolar amount of phenylacetylene instead of 1-heptin, and 0.37 g of an anthraquinone dye represented by the following structural formula was obtained.

Using the thus-obtained anthraquinone dye, a guest-host device was prepared in the same manner as in Example 1, the maximum absorption wavelength and the value of the order parameter (S) were calculated, and the results are 2 It is shown in Table No. 24.

Example 8 The dyes shown in Table 2 below were produced in the same manner as in Example 1. The order parameter (S) and the maximum absorption wavelength were measured, and the results are also shown in Table 2.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display area C09K 19/60 F 7457-4H

Claims (2)

[Claims] 1. A general formula [I] [In the formula, R ^{1 to} R ⁴ represent a hydrogen atom, a hydroxy group or an amino group which may be substituted with an alkyl group or an aryl group, and R ⁵ represents a hydrogen atom, an alkyl group or an aryl group, R ⁶ is a hydrogen atom or —C≡C
Shows the -R ^5. However, R ¹ and R ² do not represent hydrogen atoms at the same time. ] The anthraquinone type | system | group dye shown by these. 2. A general formula [I] [Wherein, R ^{1 to} R ⁴ represent a hydrogen atom, a hydroxy group, or an amino group which may be substituted with an alkyl group or an aryl group, and R ⁵ represents a hydrogen atom, an alkyl group, or an aryl group. , R ⁶ is a hydrogen atom or —C≡C
Shows the -R ^5. However, R ¹ and R ² do not represent hydrogen atoms at the same time. ] The liquid crystal composition containing the anthraquinone type | system | group dye shown by these, and a liquid crystal.