JPS62277471A - Anthraquinone compound and liquid crystal composition containing said compound - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I [R1 is cyclohexyl(oxyethyl) or 1-18C alkyl which may be interrupted by 1-3 O atoms; R2 and R3 are H, F, Cl, methyl or ethyl; A, B and C are 1-12C alkyl, 1-12C alkoxy, nitro, 2-8C dialkylamino, carboxylic acid 1-4C alkyl ester, F, Cl, Br or H]. EXAMPLE:A compound expressed by formula II. USE:A coloring matter for guest-host type liquid crystal display devices, near infrared absorption films or absorption plates or colorant for optical recording materials, polyester fibers or synthetic resins. PREPARATION:For example, 1,5-dihydroxy-4,8-dinitroanthraquinone is reacted with a compound expressed by formula III in the presence of boric acid in sulfuric acid, preferably at 0-20 deg.C to give a compound expressed by formula IV, which is then reacted with a compound expressed by formula V in a solvent, e.g. nitrobenzene, etc., at 120-180 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to novel anthraquinone compounds. More specifically, the present invention relates to a novel anthraquinone compound useful as a coloring agent for guest-host type liquid crystal display devices, near-infrared absorption films or absorption plates, optical recording materials, polyester fibers, and synthetic resins.

Conventional technology In the field of guest-host type liquid crystal display devices, one type of optical shutter using a black dye (mixture) has been developed for use in large displays for automobiles, etc., and the dyes mainly include anthraquinone dyes and azo dyes. A mixture of pigments is used.

On the other hand, known near-infrared absorbing dyes include cyanine dyes, merocyanine dyes, triphenylmethane dyes, polymethine dyes, phthalocyanine dyes, squarylium dyes, naphthoquinone dyes, and organometallic complex dyes. is widely used as a compound (dye) for dyeing synthetic fibers, synthetic resins, and natural fibers with high fastness, with a hue ranging from yellow to true yellow.

However, anthraquinone compounds that exhibit strong absorption in the near-infrared region have not been well known.

Problems to be Solved by the Invention The black dye (formulation) used as a light shutter for guest-host liquid crystal displays exhibits an absorption maximum near 680 to 700 nm, high dichroism, and high solubility in liquid crystals. ″ff Because there is no color pigment, depending on the light source,
If the entire display appears reddish, it has a drawback.

On the other hand, conventionally known near-infrared absorbers, such as the aforementioned cyanine dyes, polymethine dyes, and triphenylmethane dyes, do not have sufficient fastness, so they cannot be used in near-infrared absorption films or absorption plates. As a result of intensive studies to solve the above-mentioned problems, the present inventors found that the following formula (1) (In formula (1), R+ is a cyclohexyl group, a cyclohexyloxyethyl group, or 1 to 3 [E atoms] an optionally interrupted C1-16 alkyl group, R
2 and R3 each independently represent a hydrogen atom, fluorine atom, chlorine atom, methyl group or ethyl group, A, B and C each independently represent a Cl-12 alkyl group, a C1-12 alkoxy group,
Nitro group, dialkylamine group having 2 to 8 carbon atoms, carboxylic acid alkyl (C, ~4) ester group, fluorine atom,
A novel anthraquinone compound, each represented by a chlorine atom, a bromine atom, or a hydrogen atom, is
30 nm, has high dichroism, has extremely good solubility in liquid crystals, and can improve the display quality of guest-host G-crystal display elements by adding it as a blending component of black pigment. In addition, they discovered that it has excellent thermal stability and light fastness and good compatibility with resins, and can be used as a sharp cut filter for infrared light sensors, thereby completing the present invention.

The anthraquinone compound represented by formula (1) of the present invention can be synthesized, for example, as follows. That is, 1.
5-dihydroxy-4,8-dinitroanthraquinone in sulfuric acid in the presence of boric acid at 10 to -30°C, preferably 0 to 2
At 0°C, it is reacted with a compound represented by formula (2) (in formula (2), Rt , R2 and R3 have the same meanings as above. and R3 have the same meanings as above.) If the purity is low (.), it is purified until the desired purity is changed by recrystallization or column chromatography, and then nitrobenzene, ortho In a solvent such as chlorobenzene, a compound of formula (3) and a compound of formula (4) are combined.
) (In formula (4), A, B and C represent the same meanings as above.

) The anthraquinone compound represented by formula (1) is obtained by reacting the compound represented by formula (1) at 120 to 180°C.

Specific examples of the compound represented by formula (2) include butoxybenzene, heptyloxybenzene, heptyloxybenzene, octyloxybenzene, 2-butoxyethoxybenzene, 2-hexyloxyethoxybenzene, ethoxyethoxyethoxybenzene, methoxyethoxy Ethoxybenzene, cyclohexyloxybenzene, phthoxytoluene, 2-hexyloxyethoxytoluene, 2
-butoxyethoxytoluene, hexyloxyethylbenzene, 2-butoxyethoxymethaxylene/, 2-hexyloxyethoxymethaxylene, 2-hexyloxyethoxyfluorobenzene, and the like.

Specific examples of the compound represented by formula (4) include aniline, ethylaniline, butylaniline, pentylaniline, dodecaneaniline, N,N dimethylaniline, fluoroaniline, chloroaniline, fromaniline, nitroaniline, and ethoxy. Aniline, propoxyaniline,
Examples include butoxyaniline, amine benzoic acid butyl ester difluoroaniline, trichloroaniline, dimethylaniline, and the like.

The crude dye thus obtained usually has a slightly opaque purity for use in a guest-host liquid crystal display device, and is purified by recrystallization, column chromatography, preparative high performance liquid chromatography, etc. to obtain a dye of desired purity.

Conventionally, a well-known long-wavelength dye for liquid crystals of the following formula has a dichromaticity ratio of 5.
4. The solubility at -10℃ is approximately 0.2%, and the dye of the following formula has a dichroic ratio of 4.3 and a solubility at o'c of 0. , 6%, which is a quality that satisfies both dichroic ratio and solubility.

The anthraquinone compound of formula (1) of the present invention has an excellent dichroic ratio and solubility for any of biphenyl, phenylcyclohexane, ester, pyrimidine, dioxane, Schiff, azo, and azoxy liquid crystals. Has sex. For example, dichroic ratio in phenylcyclohexane liquid crystal &! 10, and has a solubility of 2.0% or more at 0°C.The thickest wavelength of absorption in liquid crystal is 67
0 to 680 nm, and has excellent quality as a long wavelength absorption dye for liquid crystals. Therefore, the anthraquinone compound of formula (1) is important when used alone as a green-blue pigment or as a compound pigment when two or more pigments are blended to produce blue, green, or black colors. In particular, when the anthraquinone compound of formula (1) of the present invention is blended into a transmissive black liquid crystal cell that uses a tungsten lamp as a light source for illumination, the reddish tone of the tungsten lamp is appropriately corrected to provide excellent visibility. , the commercial value of liquid crystal elements can be increased.

The liquid crystal composition of the present invention containing the anthraquinone compound of formula (1) is prepared as follows.

That is, one or more anthraquinone compounds of formula (1) are added to the above-mentioned host liquid crystal in an amount of 0.01 to 10
% by weight, preferably from 0.1 to 5% by weight, to obtain the composition of the present invention. The compound of the present invention can be blended with other dichroic dyes to be used as a black blended dye, and the liquid crystal composition of the present invention may also contain other optically active substances. The liquid crystal may be nematic, twisted-nematic, cholesteric-nematic phase transition type, smectic, etc., and the display method may be any method based on the positive or negative dielectric anisotropy of the liquid crystal.

As explained above, the anthraquinone compound of formula (1) of the present invention has the solubility and 2.
It is a dye that satisfies color properties, and liquid crystal compositions containing it are useful as color display materials for vehicle displays, various consumer displays, game consoles, and the like.

Further, the anthraquinone compound of formula (1) of the present invention is found to absorb up to the near-infrared region (about 760 nm) and is useful as a near-infrared absorber. Therefore, for example, it has poor compatibility with organic solvents and synthetic resins (e.g., polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, epoxy resin, etc.) and has a variety of processability. It is used as a material.

Next, the present invention will be explained in more detail with reference to Examples. In the examples, parts represent parts by weight.

Example 1 Dye 1 In 140 parts of concentrated sulfuric acid, 4.1 parts of water, 3.3 parts of boric acid, 1.
5-dihydroxy-4,8-dinitroanthraquinone 3
．． Dissolve 6 parts and cool to -5°C. Next. - 5.8 parts of hexyloxybenzene was added dropwise at the same temperature, and
The mixture was stirred for a period of time at the same temperature. Next, dilute the reaction mixture in ice water with
The boric acid ester was hydrolyzed by stirring at 95° C. for 2 hours. After cooling, it was filtered, thoroughly washed with water, and then dried.

The obtained crude product was purified by silica gel chromatography and developed with xylene solvent.

3.0 parts of the purified product and 3.4 parts of bulk n-butylaniline were dissolved in 10 parts of orthodichlorobenzene and reacted at 150 to 155°C for 5 hours. After the reaction, 40 parts of methanol was added and the precipitated crystals were separated and washed with methanol.

After washing with water and drying to obtain 3.1 parts of crude dye 1, dissolve it in xylene, remove impurities, and then use a silica gel column chroma!・Purified dye xt was obtained by pyrographing, developing with xylene solvent for purification, concentrating the solvent, and recrystallizing with acetone.

The color of this dye dissolved in tetrahydrofuran is bluish-green and hm
ax is 671 (628) nm (THF) Example 2 Dye 2 In Example 1, 2-n-hexyloxyethoxybenzene 7,2 was used instead of n-hexyloxybenzene.
m wo, para-n- instead of varalobylaniline
The reaction was carried out in the same manner as in Example 1 using 3.7 parts of pentylaniline, and the obtained crude dye 2 was purified in the same manner as in Example 1 to obtain purified dye 2.

The color of this dye dissolved in tetrahydrofuran is blue-green and λm
ax is 671 (628 Jnm (THF)).

Application example 3゜ Purified dye 1 obtained in Example 1 was added at 1% (weight ratio) to liquid crystal ZLI-1565 manufactured by Merck, and two transparent glass electrode substrates subjected to homogeneous alignment treatment were heated to approximately 8 μm.
The cells are sealed in cells facing each other with an interval of m, and the voltage is turned on.
When turned off, a good blue-green display was obtained. Its dichroic ratio was 9.7. In addition, 2.0% (weight ratio) of the dye 1 was added to liquid crystal ZLI-1565, heated to 70'C to dissolve, and then stored in a constant temperature room at 0°C for 3 weeks, but no crystals were deposited. I was not able to admit.

Application Example 4 Each dye was added to liquid crystal ZLI-1840 manufactured by Merck in the following proportions to prepare a black liquid crystal.

Purified Dye 1 of Example 1 0.8% H This black liquid crystal was sealed in a cell in which two transparent glass electrode substrates subjected to homogeneous alignment treatment were placed facing each other at a distance of about 8 μm, and the voltage was turned on and off. A good pure black display was obtained.

Application Example 1 10.2 parts of the purified dye obtained in Example 1 was thoroughly mixed with 100 parts of polymethyl methacrylate.

This was heated to 220.degree. C. to melt it, put it in a mold, and molded it to obtain a pale green-blue colored resin plate with a thickness of 3 m. The light absorption characteristic 7 of this material is shown in FIG. Wavelength 760 nm
It was confirmed that it effectively absorbed near-infrared rays at *.

Examples 5 to 22 Compounds (dyes) represented by the structural formulas in the following table were synthesized in the same manner as in Example 1. λmax is the value measured in tetrahydrofuran.

Effects of the Invention A new anthraquinone compound useful as a dye for liquid crystals and as an infrared absorbing material has been developed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the light absorption characteristics of a polymethyl methacrylate resin plate prepared using purified dye 1 obtained in Example 1.

Claims (1)

[Claims] 1 Formula (1) ▲ Includes mathematical formulas, chemical formulas, tables, etc. ▼ (1) (In formula (1), R_1 is interrupted by a cyclohexyl group, a cyclohexyloxyethyl group, or 1 to 3 oxygen atoms) R_2 and R_3 each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or an ethyl group, A, B and C
are each independently an alkyl group of C_1_-_1_2, C_1
_~_1_2 alkoxy group, nitro group, dialkylamino group having 2 to 8 carbon atoms, alkyl carboxylate (C_
1_～_4) Representing an ester group, a fluorine atom, a chlorine atom, a bromine atom, or a hydrogen atom, respectively) Anthraquinone compound 2 Formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) (Formula (1) ), R_1 is a cyclohexyl group, a cyclohexyloxyethyl group, or an alkyl group of C_1_ to_1_6 which may be interrupted by 1 to 3 oxygen atoms, and R_2 and R_3 are each independently a hydrogen atom, a fluorine atom, a chlorine atom, Methyl group or ethyl group, A, B and C
_ is each independently an alkyl group of C_1_ to _1_2, C_
1_ to _1_2 alkoxy group, nitro group, total number of carbon atoms 2
to 8 dialkylamino groups, alkyl carboxylates (C
_1_ to _4) A liquid crystal composition characterized by containing an anthraquinone compound represented by: