JP5186821B2 - Dichroic dye, and liquid crystal composition and liquid crystal element using the same - Google Patents

Description

  The present invention relates to a novel dichroic dye suitably used for liquid crystal displays and the like, and a liquid crystal composition and a liquid crystal element using the same.

  Many types of liquid crystal display elements have been proposed. A liquid crystal composition in which a dichroic dye is dissolved in a liquid crystal is sealed in a cell, and an electric field is applied to the liquid crystal composition in accordance with the movement of the liquid crystal by the electric field. A guest-host system that displays an image by changing the orientation of the dichroic dye and changing the light absorption state of the cell is expected as a reflective liquid crystal element that uses a backlight and consumes less power. The dichroic dye used in the liquid crystal element is required to have suitable absorption characteristics, high order parameter (S value), high solubility in the host liquid crystal, durability and the like. However, the order parameter is not sufficiently high, and as a result, the display contrast in the guest-host type liquid crystal display is lowered.

On the other hand, conventionally, various compounds in which 1,4-phenylene group and (E) -cyclohexane-1,4-diyl group are combined have been proposed in order to improve order parameters in azo dichroic dyes. (For example, Patent Documents 1 to 10), there are also proposed compounds having an order parameter as small as 0.81 at most, and an improved order parameter with the same structure (for example, Patent Documents 11 to 13). However, even these are less than 0.83 order parameters, which is not satisfactory, and is economical because it contains many 1,4-phenylene groups that require repeated carbon-carbon bond formation reactions. The disadvantages could not be avoided.
JP 58-138767 A JP 59-22964 JP 59-182877 A JP 60-36569 A JP 61-21163 A JP-A-62-252461 Japanese Patent Laid-Open No. 5-25399 JP-A-5-59294 JP-A-10-95980 JP 2000-44955 A JP 2003-96453 A JP 2003-96461 A JP 2003-96462 A

  An object of the present invention is to provide a dichroic dye that is easy to produce and has a high order parameter, and a liquid crystal composition and a liquid crystal display device using the same.

As a result of intensive studies to solve the above problems, the present inventors have found that a dichroic dye having a specific structural formula has extremely high order parameters and is easy to produce, and thus completed the present invention. It was. That is, the present invention, dichroic dye you express by the following structural formula (II), as well as, a liquid crystal device having a liquid crystal phase containing a liquid crystal composition containing the dichroic dye, and said liquid crystal composition, Is the gist.

[In formula (II), R ¹ Represents a linear or branched alkyl group having 1 to 10 carbon atoms , Ring A ¹
And ring A ² Represents (E) -cyclohexane-1,4-diyl group , L ¹ Represents a group containing an ether bond and an alkylene group having 1 to 10 carbon atoms, and a ring Ar ¹ Represents a 1,4-naphthylene group or a 1,4-phenylene group which may have an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms; ¹ Is an oxygen atom or NR ^Three (R ^Three Represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. ) And n ¹ Represents an integer of 1 to 4, R ² Represents a substituent represented by the following structural formula (III). N ¹ When Ar is 2 or more, a plurality of Ar ¹ May be the same or different. ]

[In formula (III), L ² Represents a linear or branched alkylene group having 1 to 10 carbon atoms
, L ^Three Represents a single bond or a linear or branched alkynylene group having 2 to 20 carbon atoms, and ring A ^Three And ring A ^Four Each independently represents a 1,4-phenylene group or (E) -cyclohexane-1,4-diyl group; ² Represents an integer of 1 to 3, R ^Four Represents a linear or branched alkyl group having 1 to 10 carbon atoms. N ² If L is 2 or more, multiple L ^Three And ring A ^Four May be the same or different. ]

  The present invention can provide a dichroic dye that is easy to produce and has high order parameters, and a liquid crystal composition and a liquid crystal display element using the dichroic dye.

  It is essential that the dichroic dye of the present invention has a partial structure represented by the following structural formula (I).

[In formula (I), R ¹ represents an alkyl group, and ring A ¹ and ring A ² each independently represent a 1,4-phenylene group or (E) -cyclohexane-1,4-diyl group. , L ¹ represents a divalent linking group containing no cyclic structure and no azo bond. ]

In the structural formula (I), examples of the alkyl group for R ¹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a hexyl group, and an octyl group. A linear or branched group having 1 to 10 carbon atoms, such as a straight chain group, is more preferable, and a linear alkyl group having 3 to 8 carbon atoms is particularly preferable.

Among the 1,4-phenylene group of ring A ¹ and ring A ² or (E) -cyclohexane-1,4-diyl group, as ring A ¹ , (E) -cyclohexane-1,4- A diyl group is preferred.

Further, the divalent linking group containing no cyclic structure and no azo bond in L ¹ is not particularly limited. For example, methylene group, ethylene group, propylene group, isopropylene group, butylene group, isobutylene. Group, sec-butylene group, tert-butylene group, hexylene group, octylene group or the like linear or branched alkylene group having 1 to 10 carbon atoms; vinylene group, propenylene group, isopropenylene group, butenylene group, isobutenylene Group, sec-butenylene group, tert-butenylene group, hexenylene group, octenylene group, etc., linear or branched alkenylene group having 2 to 10 carbon atoms; ethynylene group, propynylene group, isopropynylene group, butynylene group, isobutynylene group , Sec-butynylene group, tert-butynylene group, hexynylene group C2-C10 linear or branched alkynylene group such as octynylene group; methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, isopropoxycarbonyl group, tert-butoxycarbonyl group, acetyloxy group, benzoyloxy group And an ester group having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, an ether group, a carbonyl group, a group combining them, and the like.

Among these, L ¹ preferably has 2 bonding atoms, more preferably —O—CO—, —CO—O—, —CH ₂ O—, —O—CH ₂ —, and the like. -CH ₂ O- is particularly preferred.

  Specific examples of the partial structure represented by the structural formula (I) include the following structures.

  Examples of the dichroic dye of the present invention having the partial structure represented by the structural formula (I) above include, for example, an azo group having an azo bond and an anthraquinone skeleton in the structural portion other than the structural formula (I). Examples of the dichroic dye of the present invention include an azo-type dye having an azo bond in a structural part other than the structural formula (I). A chromatic dye is preferred.

  Among the azo dichroic dyes, a dichroic dye represented by the following structural formula (II) is particularly preferable in the present invention.

[In Formula (II), R ¹ , Ring A ¹ , Ring A ² and L ¹ are the same as in Structural Formula (I), and Ring Ar ¹ is an aromatic ring which may have a substituent. X ¹ represents an oxygen atom or NR ³ (R ³ represents a hydrogen atom or an alkyl group), n ¹ represents an integer of ¹ to 4, and R ² represents an optional substituent. Show. When n ¹ is 2 or more, the plurality of Ar ¹ may be the same or different. ]

In the structural formula (II), the aromatic ring of Ar ¹ means a ring having aromaticity, that is, a ring having a (4n + 2) π electron system (n is a natural number), and its skeletal structure is usually 5 or It consists of 6-membered, monocyclic or 2-6 condensed rings. The aromatic ring includes aromatic hydrocarbon rings, aromatic heterocyclic rings, and condensed rings such as anthracene ring, carbazole ring, and azulene ring. It is. Ar ¹ in the structural formula (II) is a divalent group in which two hydrogen atoms are extracted from these aromatic rings.

Specific examples of the skeleton structure of the aromatic ring Ar ¹ in the structural formula (II) include, for example, a benzene ring, naphthalene ring, quinoline ring, thieno [2,3-d] thiazole ring, thiophene ring, 2,1 , 3-benzothiazole ring and the like, among which a benzene ring and a naphthalene ring are preferable, and a substitution position of the benzene ring and naphthalene ring is preferably 1,4-position.

Examples of the substituent of the aromatic ring represented by Ar ¹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a hexyl group, and an octyl group. A linear or branched alkyl group having 1 to 20 carbon atoms; methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, hexyloxy group, C1-C20 linear or branched alkoxy group such as octyloxy group; formyloxy group, acetyloxy group, propanoyloxy group, isopropanoyloxy group, butanoyloxy group, isobutanoyloxy group Sec-butanoyloxy group, tert-butanoyloxy group, pentanoyloxy group, hex C1-C20 linear or branched acyloxy groups such as noyloxy group and octanoyloxy group; acetylamino group, propanoylamino group, isopropanoylamino group, butanoylamino group, isobutanoylamino group A linear or branched acylamino group having 1 to 20 carbon atoms such as sec-butanoylamino group, tert-butanoylamino group, pentanoylamino group, hexanoylamino group, octanoylamino group; A halogen atom such as a bromine atom and an iodine atom; a cyano group; a hydroxyl group; a nitro group, and the like. Among these substituents, the substituent having a carbon atom has 1 to 3 carbon atoms. Is preferred.

  Among these substituents, in the present invention, an alkyl group having 1 to 20 carbon atoms and an alkoxy group having 1 to 20 carbon atoms are preferable, an alkyl group having 1 to 3 carbon atoms, and 1 to 1 carbon atoms. The alkoxy group of 3 is particularly preferred.

  Further, these substituents may be one or plural, and in the case of plural, the plural substituents may be the same or different. It may combine to form a ring.

In Structural Formula (II), n ¹ which is an integer of 1 to 4 is preferably 1 to 3. In addition, as the alkyl group when X ^{1 of} oxygen atom or NR ³ (R ³ represents a hydrogen atom or an alkyl group) is NR ³ , Ar ¹ may have the above-mentioned substituents. C1-C20 linear or branched alkyl group is mentioned, and a C1-C10 alkyl group is preferable in it.

  Specific examples of the partial structure represented by the structural formula (II) having an azo bond in a structural portion other than the structural formula (I) include the following structures.

In the present invention, R ² of the optional substituent in the structural formula (II) is described above as the group represented by the structural formula (I) or the substituent that Ar ¹ may have. An alkyl group; an alkoxy group; an acyloxy group; an acylamino group; a halogen atom; a cyano group; a hydroxyl group; a nitro group, etc., wherein X ¹ and R ² are bonded to each other to form a ring. However, in order to achieve a high order parameter, it is particularly preferable that R ² is represented by the following structural formula (III).

[In the formula (III), L ² represents a divalent linking group containing no cyclic structure and an azo bond, and L ³ represents a single bond or a divalent linking group containing no cyclic structure and an azo bond. , Ring A ³ and ring A ⁴ each independently represent a 1,4-phenylene group or (E) -cyclohexane-1,4-diyl group, n ² represents an integer of 1 or more, and R ⁴ represents An alkyl group is shown. When n ² is 2 or more, the plurality of L ³ and ring A ⁴ may be the same or different. ]

In the structural formula (III), the divalent linking group that does not include the cyclic structure and the azo bond in L ² is not particularly limited. For example, as described above as L ^{1 in the} structural formula (I) A linear or branched alkylene group having 1 to 10 carbon atoms; an ether group; a carbonyl group; a group obtained by combining them; and the like. Among these, L ² includes —CH ₂ —, —CH _{2 CH 2 -, - CH 2} CH 2 CH 2 -, - CH (CH 3) -, - CH 2 CH 2 O -, - CO- , and the like are preferable.

In the structural formula (III), the divalent linking group containing no cyclic structure and azo bond in L ³ is not particularly limited. For example, as L ^{1 in the} structural formula (I), The above-mentioned linear or branched alkylene group having 1 to 10 carbon atoms; the above-described linear or branched alkenylene group having 2 to 10 carbon atoms; A branched alkynylene group; an ester group having 2 to 20 carbon atoms as described above; an ether group; a carbonyl group; a group combining them, and the like. Among these, L ³ represents —C≡C— , —CH ₂ O—, —O—CH ₂ —, —O—CO—, —CO—O— and the like are preferable.

Among the 1,4-phenylene group of ring A ³ and ring A ⁴ or (E) -cyclohexane-1,4-diyl group, at least one of ring A ³ and ring A ⁴ is (E)- Cyclohexane-1,4-diyl group is preferred, and when n ² is 1 and n ² is 2 or more, ring A ⁴ bonded to R ⁴ is (E) -cyclohexane-1, More preferred is a 4-diyl group.

In Structural Formula (III), n ² which is an integer of 1 or more is preferably 1 to 3, particularly preferably 1 or 2. Examples of the alkyl group for R ⁴ include the same as those described above for the alkyl group for R ¹ in the structural formula (I). Among these, a straight chain is more preferable, and a straight chain having 3 to 8 carbon atoms. A chain alkyl group is particularly preferred.

Specific examples of the structure represented by the structural formula (III) as R ² in the partial structure represented by the structural formula (II) include the following structures.

  The above-described dichroic dye of the present invention can be synthesized by synthesizing a compound containing the structural formula (I) by the following reaction and further combining known reactions.

Here, when L ¹ has an ester bond such as —O—CO— or —CO—O—, L ¹ is formed by, for example, subjecting a corresponding alcohol and a carboxylic acid to a condensation reaction. Examples of the condensing agent at that time include carbodiimides such as N, N′-dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride; phosgene, diphosgene, triphosgene, carbonyldiimidazole, and the like. Examples include phosgene equivalents. Alternatively, L ¹ is formed by reacting the corresponding alcohol and acid chloride in the presence of a base.

When L ¹ has an ether bond such as —CH ₂ O— or —O—CH ₂ —, for example, by reacting the corresponding alcohol with a halide or a sulfonic acid ester in the presence of a base, L ¹ is formed (Williamson ether synthesis method). Alternatively, L ¹ is formed by a condensation reaction of the corresponding alcohol and phenol using a condensing agent such as triphenylphosphine or diethyl azocarboxylate (Mitsunobu reaction).

When L ¹ is composed of a carbon atom such as an acetylene group, the corresponding ethynyl compound and aryl halide or aryl sulfonate are cross-coupled in the presence of a transition metal catalyst to form L ¹ . (Sonogashira reaction).

  Then, the synthesized compound containing the structural formula (I) is converted into a known reaction method, for example, A. V. "Dichromatic Dye for Liquid Crystal Display" by Ivashchenko (CMC, published in 1994), "Review Synthetic Dyes" by Horiguchi (Sankyo Publishing, published in 1968), and methods described in the literature cited therein, etc. The dichroic dye of this invention is compoundable by making it react using.

  In the liquid crystal composition of the present invention, one or more of the dichroic dyes described above are used as the liquid crystal device handbook (issued in Nikkan Kogyo Shimbun, 1989) edited by the 142th Committee of the Japan Society for the Promotion of Science. In various host liquid crystal compounds such as biphenyl, phenylcyclohexane, phenylpyrimidine, cyclohexylcyclohexane, etc. showing nematic or smectic phase described on pages 192 and 715-722, or host liquid crystal compositions containing these compounds It can prepare easily by mixing by a well-known method.

  The content ratio of the dichroic dye of the present invention in the liquid crystal composition of the present invention is not particularly limited, but is usually 0.05 to 15% by weight including the case of containing two or more kinds. Yes, preferably 0.1 to 5% by weight.

  Examples of the host liquid crystal compound at that time include Np-type liquid crystal compounds and Nn-type liquid crystal compounds represented by the following general formulas (IV) to (VIII).

[In formulas (IV) to (VIII), ring B represents a cyclohexane ring, a benzene ring, a dioxane ring, or a pyrimidine ring, and q represents an integer of 1 to 3. Z represents a single bond, —CO—O—, —CH ₂ CH ₂ —, —CH═CH—, or —C≡C—. Y ¹ and Y ³ each independently represent a hydrogen atom, a halogen atom such as a fluorine atom or a chlorine atom, and Y ² represents a halogen atom such as a fluorine atom or a chlorine atom, or a halogen atom such as a fluorine atom or a chlorine atom. A C1-C7 alkyl group as a substituent, also an alkenyl group, an alkoxy group, a substituted alkyl group, a substituted alkenyl group, a cyclohexyl group having a substituted alkoxy group as a substituent, or a substituted alkyl group thereof, substituted The phenyl group which has an alkenyl group and a substituted alkoxy group as a substituent is shown. Y ⁷ and Y ⁸ each independently represent a cyano group or a halogen atom such as a fluorine atom or a chlorine atom. Y ¹¹ and Y ^{13 each} represent a cyano group. Y ⁴ , Y ⁵ , Y ⁶ , Y ⁹ , Y ¹⁰ , Y ¹² , and Y ¹⁴ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 1 to 10 carbon atoms. Or an alkoxyalkyl group having 2 to 10 carbon atoms. ]

  As the liquid crystal composition of the present invention, an optically active substance that may or may not exhibit a liquid crystal phase, such as a dichroic dye other than the dichroic dye of the present invention, and cholesteryl nonanoate, You may contain various additives, such as a ultraviolet absorber and antioxidant.

  The dichroic dye of the present invention has a high value of 0.83 or more, preferably 0.85 or more, particularly preferably 0.86 or more as an order parameter in the wavelength range of 380 to 700 nm, and contains it. The liquid crystal composition can be suitably used as various electro-optical devices such as display elements for computers, watches, calculators, etc., electro-optical shutters, electro-optical apertures, optical communication optical path switching switches, optical modulators and the like.

The order parameter (S value) of the dye can be obtained from the following formula described in “Liquid Crystal Device Handbook” edited by the 142th Committee of the Japan Society for the Promotion of Science based on spectroscopic measurement.
S = (A // − A⊥) / (2A⊥ + A //)
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, and the S value is theoretically in the range of 0 to 1. The closer the value is to 1, the more the contrast as a guest-host type liquid crystal element is improved.

  The liquid crystal element of the present invention is obtained by sandwiching the liquid crystal composition containing the dichroic dye of the present invention between two substrates with electrodes, at least one of which is transparent. “Latest Liquid Crystal Technology” (Industry Research Committee, published in 1983), p. L. Heilmeier-type guest hosts described in Fergason, SID85Digest, 68 (1985), “Liquid Crystal Device Handbook” (Nikkan Kogyo Shimbun, 1989) pages 315-329, etc. Various liquid crystal elements using a guest host effect such as a transition type guest host can be formed. As described above, various modes of the liquid crystal element can be used in the present invention. However, in the phase transition mode obtained by adding an optically active substance to the nematic liquid crystal composition, a polarizing plate is not used. Since the contrast is high and the display is bright, it is particularly preferable as a reflective liquid crystal display element.

  As an example of the liquid crystal element of the present invention, FIGS. 1 and 2 are schematic cross-sectional views of an active drive type phase change mode guest-host type liquid crystal display element. FIG. 1 shows a voltage application state of the liquid crystal display element, and FIG. 2 shows a voltage non-application state. In the figure, 1 is incident light, 3 is a transparent glass plate, 4 is a transparent electrode, 5 is an alignment film, 6 is a liquid crystal compound molecule, 7 is a dichroic dye molecule, 9 is a reflective layer, and 10 is reflected light.

  When no voltage is applied (FIG. 2), the liquid crystal compound molecule 6 exhibits a cholesteric phase, and the dichroic dye molecule 7 also exhibits a cholesteric structure together with the liquid crystal compound molecule 6. Therefore, even if the incident light 1 is natural light, the polarizing plate Is absorbed by the dichroic dye molecule 7 without using. When a voltage is applied (FIG. 1), the liquid crystal compound molecules 6 and the dichroic dye molecules 7 are aligned in the direction of the electric field, so that light is transmitted and reflected by the reflective layer 9. Thus, in a liquid crystal element, light transmission and absorption can be controlled by the presence or absence of an electric field.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

<Synthesis of Intermediate “M06”>
The intermediate “M06” was synthesized according to the following reaction formula.

Reaction 1
A mixture of 50.4 g (180 mmol) of “M01”, 500 ml of methanol and 2.4 ml of concentrated sulfuric acid was heated under reflux for 3 hours, cooled to room temperature, and concentrated under reduced pressure. Ice water (250 ml) and hexane (500 ml) were added, insoluble matter was filtered off, the filtrate was separated, and the organic layer was washed with water (250 ml) and saturated brine (250 ml). The extract was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain 48.5 g (yield 92%) of “M02” as white crystals.

Reaction 2
15.4 g (410 mmol) of lithium aluminum hydride was suspended in 250 ml of tetrahydrofuran (THF), and a solution of 48.3 g (164 mmol) of “M02” in 500 ml of THF was added dropwise with cooling in an ice bath. After refluxing for 2 hours, the mixture was cooled in an ice bath, and 250 ml of THF, 150 ml of ethyl acetate, and 250 ml of 20% sulfuric acid aqueous solution were successively added dropwise. The insoluble material was removed by celite filtration and washed with ethyl acetate. The filtrate was partitioned by adding 500 ml of 1N hydrochloric acid, and the organic layer was washed successively with 500 ml of water and saturated brine, and dried over anhydrous sodium sulfate. Concentration under reduced pressure gave 40.9 g (94% yield) of “M03”.

Reaction 3
To a mixture of 17.0 g (64 mmol) of “M03”, 13.7 g (64 mmol) of “M04”, 18.3 g (70 mmol) of triphenylphosphine and 200 ml of THF, a 2.2N toluene solution of diethyl azodicarboxylate in a water bath 31. 8 ml (70 mmol) was added dropwise and stirred at room temperature for 2 hours. Methanol was added, and the resulting precipitate was collected by filtration and washed with methanol to obtain 23.5 g (yield 80%) of “M05”.

Reaction 4
A mixture of 25 g (55 mmol) of “M05”, 49.6 g (207 mmol) of sodium sulfide nonahydrate, 1 L of THF, and 0.5 L of ethanol was heated to reflux for 3 hours. After cooling to room temperature, 1 L of water was added, and after stirring, the precipitate was collected by filtration and washed with water and methanol to obtain 22.6 g of “M06” (yield 97%).

<Synthesis of Intermediate “M08”>
The intermediate “M08” was synthesized according to the following reaction formula.

Reaction 5
23.38 g (83 mmol) of “M01”, 12.11 g (85 mmol) of 1-naphthylamine and 1.57 g (12.9 mmol) of N, N-dimethylaminopyridine were suspended in 95 ml of dichloromethane and cooled on ice. A suspension of 17.89 g (93.3 mmol) of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride in 95 ml of dichloromethane was added, and the mixture was returned to room temperature and stirred overnight. 1N hydrochloric acid was added and filtered. The wet cake was washed with water, methanol and hexane in this order, and dried to obtain 31.6 g (yield 94%) of “M07”.

Reaction 6
To a mixture of 31.6 g (77.9 mmol) of “M07” and 300 ml of THF, 6.79 g (179 mmol) of sodium borohydride was added, and after cooling in an ice bath, a solution of 23.7 g (93.4 mmol) of iodine in 200 ml of THF was added dropwise. . After heating under reflux for 2 hours, the mixture was cooled in an ice bath, 100 ml of 1N hydrochloric acid and 200 ml of 1N aqueous sodium hydroxide solution were successively added dropwise, 250 ml of ethyl acetate was added, and the organic layer was separated. The organic layer was washed with saturated brine and dried over anhydrous sodium sulfate. After concentration under reduced pressure, methanol was added and the resulting precipitate was collected by filtration and washed with methanol to obtain 24.6 g (yield 81%) of “M08”.

<Synthesis of Intermediate “M13”>
Intermediate “M13” was synthesized according to the following reaction formula.

Reaction 7
"M09" 5.00 g (37.8 mmol), "M10" 11.7 g (37.8 mmol), triethylamine 100 ml, copper (I) iodide 0.16 g (0.86 mmol), tetrakis (triphenylphosphine) palladium ( 0) 1.0 g (0.86 mmol) of the mixture was heated to reflux for 3 hours under a nitrogen atmosphere. After cooling to room temperature, 50 ml of ethyl acetate was added, insoluble matter was removed by filtration, and the mixture was washed with ethyl acetate. The mother liquor was concentrated, and the resulting powder was suspended and washed with methanol to obtain 8.63 g (yield 63%) of “M11”.

Reaction 8
1.80 g (5.0 mmol) of “M11” and 1.99 g (6.0 mmol) of carbon tetrabromide were dissolved in 7 ml of THF, and 1.57 g (6.0 mmol) of triphenylphosphine was gradually added at room temperature. After reacting at room temperature for 20 minutes, methanol was added, and the precipitate was collected by filtration and washed with methanol to obtain “M12”.

Reaction 9
A mixture of 1.14 g (15 mmol) of 1-naphthylamine, 1.4 g (10 mmol) of potassium carbonate and 10 ml of N, N-dimethylformamide (DMF) was heated to 100 ° C., and the total amount of “M12” obtained in Reaction 8 was reduced. Suspended in 20 ml of DMF and added. After stirring at 100 ° C. for 2 hours, the mixture was cooled to room temperature, methanol and water were added, the precipitate was collected by filtration and suspended and washed with methanol to obtain 1.94 g of “M13” (yield from “M11” 80%). It was.

<Synthesis of Intermediate “M18”>
Intermediate “M18” was synthesized according to the following reaction formula.

Reaction 10
In a mixture of “M14” 4.77 g (20 mmol), phthalimide 2.94 g (20 mmol), triphenylphosphine 5.77 g (22 mmol), and THF 100 ml synthesized from the corresponding carboxylic acid in the same manner as in Reaction 1 and Reaction 2, 10 ml (22 mmol) of a 2.2 mol / L toluene solution of diethyl dicarboxylate was added at room temperature, stirred at room temperature for 2 hours, and then purified by silica gel column chromatography (silica gel 500 g, hexane / ethyl acetate = 10/1 to 5/1). As a result, 6.83 g (yield 93%) of “M15” was obtained.

Reaction 11
6.83 g (18.6 mmol) of “M15” and 2 ml (41 mmol) of hydrazine monohydrate were added to 100 ml of ethanol, and the mixture was heated to reflux for 1.5 hours. After cooling to room temperature, the precipitate was filtered off, washed with THF, the filtrate was concentrated, 1N aqueous sodium hydroxide solution was added, and the mixture was extracted with a mixed solvent of THF and ether. The organic layer was washed with water and saturated brine, and dried over anhydrous sodium sulfate. After concentration under reduced pressure, the obtained amorphous substance was suspended in methanol, and 30 ml of 1N hydrochloric acid was added. Methanol was distilled off, and the precipitate was collected by filtration and washed with water to obtain 2.13 g (42% yield) of “M16”.

Reaction 12
J. et al. Am. Chem. Soc. 98,3237 (1976), and synthesized "M17" 1.84 g (7.76 mmol), "M16" 2.13 g (7.78 mmol), toluene 20 ml, sodium tert-butoxide 1.86 g (19 .4 mmol), 0.18 g (0.20 mmol) of Pd ₂ (dba) ₃ , 0.36 g (0.58 mmol) of rac-BINAP, 2 hours at 85 ° C., 2 hours at 95 ° C., 2 hours at 105 ° C. After stirring at 115 ° C. for 0.5 hour, the mixture was cooled to room temperature, added with water and ethyl acetate, filtered through celite, and washed with ethyl acetate. The filtrate was separated, and the organic layer was washed with water and saturated brine, and dried over anhydrous sodium sulfate. After concentration under reduced pressure, purification by silica gel column chromatography (silica gel 100 g, hexane / ethyl acetate = 100/1 to 20/1 to 10/1 to 4/1), the powder was washed with methanol / water, and “M18” 2.56 g (84% yield) was obtained.

<Synthesis of Intermediate “M25”>
Intermediate “M25” was synthesized according to the following reaction formula.

Reaction 13
To a mixture of 19.0 g (77 mmol) of “M19” and 380 ml of dichloromethane was added a solution of 24.2 g (86 mmol) of trifluoromethanesulfonic anhydride in 60 ml of dichloromethane. A solution of 7.1 ml (90 mmol) of pyridine in 25 ml of dichloromethane was added dropwise under ice cooling, and after stirring at room temperature for 4 hours, 350 ml of ice water was added. The organic layer was separated, the aqueous layer was extracted with dichloromethane, and the combined dichloromethane layer was washed with saturated brine and dried over anhydrous sodium sulfate. The filtrate was concentrated under reduced pressure and purified by silica gel column chromatography (silica gel 800 g, hexane) to obtain 24.25 g (99% yield) of “M20”.

Reaction 14
To a mixture of 27.2 g (72 mmol) of “M20”, 14.3 g (79 mmol) of “M21”, 22.9 g (216 mmol) of sodium carbonate, 22 ml of ethanol, 90 ml of water and 200 ml of toluene, tetrakis (triphenylphosphine) was added under a nitrogen atmosphere. ) Palladium (0) (3.0 g, 3 mmol) was added, and the mixture was stirred at 60 ° C. for 7 hours. After cooling to room temperature, water was added, insoluble material was removed by Celite filtration, and the filtrate was extracted with ethyl acetate. The organic layer was washed with saturated brine and dried over anhydrous sodium sulfate. The mixture was concentrated under reduced pressure and purified by silica gel column chromatography (silica gel 750 g, hexane / dichloromethane = 9/1 to 1/4). The resulting powder was suspended and washed with hexane / dichloromethane to obtain 10.9 g of “M22” ( Yield 42%).

Reaction 15
21.2 g (59 mmol) of “M22” was added dropwise to a mixture of 4.9 g (129 mmol) of lithium aluminum hydride and 75 ml of THF under ice cooling, and the mixture was heated to reflux for 2 hours. Under ice-cooling, 75 ml of THF, 45 ml of ethyl acetate, and 70 ml of 20% aqueous sulfuric acid solution were successively added dropwise, the insoluble material was removed by Celite filtration, and the mixture was washed with ethyl acetate. The filtrate was washed successively with 250 ml of 1N hydrochloric acid, 250 ml of water and 250 ml of saturated brine, and dried over anhydrous sodium sulfate. Concentration under reduced pressure yielded 19.3 g (99% yield) of “M23”.

Reaction 16
30 ml of 30% hydrobromic acid acetic acid solution was added to 5.0 g (14.9 mmol) of “M23”, stirred at 90 ° C. for 3 hours, cooled to room temperature, iced water was added, and the resulting crystals were collected by filtration. Washing with water and methanol gave 5.6 g (95% yield) of “M24”.

Reaction 17
A mixture of 5.3 g (13.3 mmol) of “M24”, 2.28 g (16 mmol) of 1-naphthylamine, 2.2 g of potassium carbonate, and 100 ml of DMF was stirred at 60 to 70 ° C. for 5 hours and cooled to room temperature. Water was added, and the insoluble matter obtained by filtration was purified by silica gel column chromatography (silica gel 100 g, hexane / dichloromethane = 5/1 to 3/1) to obtain 4.02 g (yield 66%) of “M25”. It was.

Example 1 and Comparative Example 1
Using the intermediate “M06” obtained above, a dichroic dye “Compound 1” was synthesized according to the following reaction formula.

Reaction 18
10.4 g (24 mmol) of “M06”; Org. Chem. 44, 2510 (1979). A mixture of 3.65 g (24 mmol) of “M26” and 300 ml of acetic acid was stirred at 50 ° C. for 5 hours. After cooling to room temperature, methanol and water were added, and the precipitated solid was collected by filtration and washed with water and methanol to obtain 14.0 g of “M27” (quantitative yield).

Reaction 19
A mixture of 13.5 g (23.8 mmol) of “M27”, 21.5 g (89.5 mmol) of sodium sulfide nonahydrate, 600 ml of THF, and 300 ml of ethanol was heated to reflux for 1.5 hours. After cooling to room temperature, 500 ml of water was added, and the precipitate was collected by filtration and suspended and washed with water and methanol to obtain 13.1 g (quantitative yield) of “M28”.

Reaction 20
“M28” 0.28 g (0.51 mmol), “M24” 0.20 g (1.1 mmol), potassium carbonate 0.15 g (1.1 mmol), potassium iodide 0.024 g (0.14 mmol), N-methyl A mixture of 36 ml of -2-pyrrolidone (NMP) was stirred at 100 ° C. for 5 hours. Methanol was added after cooling with ice, and the precipitate was collected by filtration and purified by silica gel column chromatography (silica gel 50 g, hexane / chloroform = 1/1 to 0/1), suspended and washed with chloroform / ethyl acetate, 0.010 g (yield 13%) of the chromatic dye “Compound 1” was obtained.

The resulting dichroic dye “Compound 1” was dissolved in a fluorine-based liquid crystal mixture commercially available from Merck as “MCL-2039” at a concentration of 0.1% by weight to prepare a guest-host liquid crystal composition. . The liquid crystal composition was sealed in a cell having a gap of 50 μm that was configured so that two glass substrates with transparent electrodes coated, cured, and rubbed with a polyimide resin face each other and the liquid crystal was aligned in parallel. The absorbance (A //) for linearly polarized light parallel to the orientation direction of the colored cell and the absorbance (A⊥) for polarized light perpendicular to the orientation direction were measured, and the absorbance (A //) at the absorption peak (λmax) and From the absorbance (A 値), the order parameter (S value) was calculated from the following formula, and the results are shown in Table 1 together with “Comparative Compound 1”.
S = (A // − A⊥) / (2A⊥ + A //)

Example 2 and Comparative Example 2
Using the intermediate “M06” obtained above, a dichroic dye “Compound 2” was synthesized according to the following reaction formula.

Reaction 21
To a mixture of 4.3 g (9.9 mmol) of “M06” and 220 ml of NMP, 2.66 ml (30 mmol) of concentrated sulfuric acid and 0.725 g (10.5 mmol) of sodium nitrite were dissolved in a small amount of water under ice cooling. The mixture was further stirred for 2 hours under ice cooling. 0.188 g of amidosulfuric acid was dissolved in a small amount of water and added, and stirred for a while under ice cooling to obtain a diazo solution. In a separate container, take a mixture of 1.43 g (10 mmol) of 1-naphthylamine, 22 ml of acetic acid, and 11 ml of water, add the diazo solution dropwise under ice cooling, stir for 30 minutes under ice cooling, and then stir at room temperature for a while. . The mixture was ice-cooled again, a solution of 2.4 g (30 mmol) of sodium acetate in 200 ml of water was added, 100 ml of ethanol and 2.4 g (30 mmol) of sodium acetate were added to the resulting precipitate, and the mixture was stirred at room temperature for 1 hour. And purified by silica gel column chromatography (silica gel 150 g, hexane / chloroform = 3 / 2-chloroform to chloroform / methanol = 100/1), suspended and washed with dichloromethane / methanol, and 2.91 g (yield) of “M29”. 51%) was obtained.

Reaction 22
To a mixture of 2.5 g (4.3 mmol) of “M29” and 250 ml of NMP, 3.8 ml (43 mmol) of concentrated sulfuric acid and 0.326 g (4.7 mmol) of sodium nitrite were dissolved in a small amount of water under ice cooling. The mixture was further stirred for 4 hours under ice cooling. 0.543 g of amidosulfuric acid was dissolved in a small amount of water and added, and stirred for a while under ice cooling to obtain a diazo solution. In a separate container, a mixture of 4.0 g (43 mmol) of phenol and 120 ml of ice water was taken, and sodium acetate was added to adjust the pH to 8. Then, the diazo solution was added dropwise while keeping the internal temperature at 10 ° C. or lower under ice cooling. During this time, 1N aqueous sodium hydroxide solution was added dropwise to maintain the pH of the reaction solution at 8-10. After the drop yield, the temperature was raised to room temperature, and the precipitate was collected by filtration and washed with water and methanol. Purified by silica gel column chromatography twice (first time: 200 g of silica gel, dichloromethane / methanol = 1/0 to 10/1, second time: silica gel 35 g, chloroform / methanol = 1/0 to 10/1). The resulting solid was suspended and washed with dichloromethane / methanol to obtain 1.09 g (yield 37%) of “M30”.

Reaction 23
A mixture of 0.380 g (0.55 mmol) of “M30”, 0.241 g (0.61 mmol) of “M24”, 0.115 g (1.1 mmol) of potassium carbonate, and 35 ml of NMP was stirred at 70 ° C. for 2 hours. After adding 0.022 g of “M24” and 0.010 g of potassium carbonate and stirring at 70 ° C. for 2 hours, 0.44 g of “M24” and 0.020 g of potassium carbonate were added and stirred at 70 ° C. for 1 hour. After cooling to room temperature, the precipitate was collected by filtration, washed with water and methanol, and suspended and washed successively with THF, DMF, and methanol to obtain 0.35 g of dichroic dye “Compound 2” (yield 63%). It was.

  For the obtained dichroic dye “Compound 2”, the order parameter (S value) was calculated from the absorbance at the absorption peak (λmax) in the same manner as in Example 1, and the results are shown in Table 2 together with “Comparative Compound 2”. It was shown to.

Examples 3-6, Comparative Example 3
Using the intermediate “M06” obtained above, a dichroic dye “Compound 3” was synthesized according to the following reaction formula.

Reaction 24
0.22 g of “M06” was dissolved in 30 ml of NMP, 0.2 ml of concentrated sulfuric acid and 1 ml of water of 0.036 g of sodium nitrite were added at 0 ° C., and the mixture was stirred at 0 ° C. for 2 hours. In a separate container, a solution of 0.20 g of intermediate “M08” obtained in <Synthesis of Intermediate “M08”> in 5 ml of NMP was taken, and the reaction solution was added at 0 ° C. After stirring for 10 minutes, 1 g of sodium acetate and 20 ml of methanol were added, and the precipitate was collected by filtration and purified by silica gel column chromatography (silica gel 50 g, hexane / chloroform = 1/1 to 0/1) and ethanol suspension washing. Thus, 0.17 g (yield 41%) of the dichroic dye “compound 3” was obtained.

  Further, in the above reaction 24, the same as the above reaction 24 except that instead of “M08”, the following “M32” synthesized using a phenol compound in the same manner as in the above <synthesis of intermediate “M18”> was used. Thus, a dichroic dye “compound 4” was synthesized.

  Further, in the reaction 24, a dichroic property was obtained in the same manner as in the reaction 24 except that the intermediate “M25” obtained in <Synthesis of the intermediate “M25”> was used instead of “M08”. The dye “Compound 5” was synthesized.

  Further, in the reaction 24, a dichroic property was obtained in the same manner as in the reaction 24 except that the intermediate “M13” obtained in <Synthesis of the intermediate “M13”> was used instead of “M08”. The dye “Compound 6” was synthesized.

  For the obtained dichroic dyes “compounds 3 to 6”, the order parameter (S value) was calculated from the absorbance at the absorption peak (λmax) in the same manner as in Example 1, and the results were shown together with “Comparative Compound 3”. It is shown in Table 3.

Examples 7-9, Comparative Example 4
From the intermediate “M31” synthesized in the same manner as “M28” using “M14” as a raw material and the intermediate “M25” obtained in the above <Synthesis of intermediate “M25”>, the following reaction formula The dichroic dye “Compound 7” was synthesized according to the above.

Reaction 25
A mixture of 0.37 g (0.7 mmol) of “M31” and 20 ml of NMP was ice-cooled, 0.2 ml of concentrated sulfuric acid and a solution of 0.057 g (0.8 mmol) of sodium nitrite in 0.5 ml of water were added, and the mixture was ice-cooled. The mixture was stirred for 1 hour to obtain a diazo solution. In a separate container, take a mixture of 0.33 g (0.7 mmol) of intermediate “M25” obtained in <Synthesis of intermediate “M25”> and 3 ml of NMP, add a diazo solution under ice cooling, and Stir for 1 hour. The mixture was ice-cooled, sodium acetate and water were added, and the precipitate was collected by filtration and washed with methanol. Purification by silica gel column chromatography (silica gel 75 g, hexane / chloroform = 1/2 to 1/9), and the resulting solid was washed in turn with chloroform / ethyl acetate and THF / ethyl acetate. 0.195 g (yield 28%) of Compound 7 ”was obtained.

  Further, in the reaction 25, two colors were used in the same manner as in the reaction 25 except that the intermediate “M28” was used instead of “M31” and the intermediate “M32” was used instead of “M25”. A functional dye “Compound 8” was synthesized.

  Further, in the reaction 25, dichroism was performed in the same manner as in the reaction 25 except that the intermediate “M13” obtained in the above <synthesis of intermediate “M13”> was used instead of “M25”. The dye “Compound 9” was synthesized.

  For the obtained dichroic dyes “compounds 7 to 9”, the order parameter (S value) was calculated from the absorbance at the absorption peak (λmax) in the same manner as in Example 1, and the results were shown together with “Comparative Compound 4”. Table 4 shows.

Example 10 and Comparative Example 5
Using the intermediate “M33” synthesized in the same manner as “M29” using “M14” as a raw material, a dichroic dye “Compound 10” was synthesized according to the following reaction formula.

Reaction 26
A mixture of “M33” (6.73 g, 12.0 mmol) and NMP (300 ml) was ice-cooled, 3 ml of concentrated hydrochloric acid and a solution of 1.28 g (13.2 mmol) of sodium nitrite in 5 ml of water were added, and the mixture was stirred for 1 hour. A solution of 0.65 g (3.6 mmol) in 1 ml of water was added and stirred for 30 minutes to obtain a diazo solution. In a separate container, a mixture of 1.77 g (12.4 mmol) of 1-naphthylamine, 30 ml of acetic acid, 1.22 g of sodium acetate, and 5 ml of water was ice-cooled, the diazo solution was added, and the mixture was washed with 150 ml of NMP. After returning to room temperature and stirring for 1 hour, the mixture was cooled on ice, a solution of 1.2 g of sodium acetate in 300 ml of water was added, the precipitate was collected by filtration, and silica gel column chromatography (silica gel 350 g, chloroform / hexane = 1/1 to 0/1). ) To obtain 0.40 g (yield 5%) of “M34”.

Reaction 27
A mixture of 0.39 g (0.55 mmol) of “M34” and 25 ml of DMF was ice-cooled, and a solution of 0.15 ml (1.8 mmol) of concentrated hydrochloric acid and 0.0552 g (0.57 mmol) of sodium nitrite in 0.3 ml of water was added. The mixture was further stirred for 1 hour under ice cooling. A solution of 0.0192 g (0.11 mmol) of amidosulfuric acid in 0.1 ml of water was added and stirred for 10 minutes to obtain a diazo solution. In a separate container, take a mixture of 0.214 g (0.54 mmol) of intermediate “M18” obtained in <Synthesis of intermediate “M18”> and 7 ml of DMF, add a diazo solution under ice-cooling, and Stir for 30 minutes. The mixture was ice-cooled again, and a solution of 0.061 g of sodium acetate in 50 ml of water was added and filtered. The wet cake was suspended in ethanol, sodium acetate was added, and the mixture was stirred at room temperature and filtered. The obtained solid was purified twice by silica gel column chromatography (silica gel 75 g, chloroform / methanol = 1/0 to 50/1), and the obtained solid was suspended and washed three times with THF / ethyl acetate. 0.036 g (yield 6%) of the chromatic dye “Compound 10” was obtained.

  For the obtained dichroic dye “Compound 10”, the order parameter (S value) was calculated from the absorbance at the absorption peak (λmax) in the same manner as in Example 1, and the results are shown in Table 5 together with “Comparative Compound 5”. It was shown to.

  As described above, from Tables 1 to 5 showing the results collectively for each dye compound having the same dye skeleton, the dye compound of the present invention has a higher S value than the compound of the comparative example, and is represented by the general formula (I). It is clear that the introduction of such a partial structure has a great effect on improving the S value of the dichroic dye.

1 is a schematic cross-sectional view in a voltage application state of a phase transition mode guest-host type liquid crystal display device showing an embodiment of a liquid crystal device of the present invention. 1 is a schematic cross-sectional view of a phase transition mode guest-host type liquid crystal display device showing an embodiment of the liquid crystal device of the present invention in a state where no voltage is applied. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Incident light 3; Transparent glass substrate 4; Transparent electrode 5; Alignment film 6; Liquid crystal compound molecule 7; Dichroic dye molecule 9;

Claims (3)

The dichroic dye, wherein the benzalkonium represented by the following structural formula (II).

[In the formula (II), R ¹ represents a linear or branched alkyl group having 1 to 10 carbon atoms. , Ring A ¹ and ring A ² represent (E) -cyclohexane-1,4-diyl group , L ¹ is an ether bond
And a group containing an alkylene group having 1 to 10 carbon atoms, the ring Ar ¹ is a 1,4-naphthylene group which may have an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, or 1,4-phenylene group, X ¹ represents an oxygen atom or NR ³ (R ³ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms); n ¹ represents an integer of ¹ to 4, and R ² represents a substituent represented by the following structural formula (III). When n ¹ is 2 or more, the plurality of Ar ¹ may be the same or different. ]

[In the formula (III), L ² represents a linear or branched alkylene group having 1 to 10 carbon atoms, and L ³ represents a single bond or a linear or branched alkynylene group having 2 to 20 carbon atoms. Ring A ³ and ring A ⁴ each independently represents a 1,4-phenylene group or (E) -cyclohexane-1,4-diyl group, and n ² represents an integer of 1 to 3. , R ⁴ represents a linear or branched alkyl group having 1 to 10 carbon atoms. When n ² is 2 or more, the plurality of L ³ and ring A ⁴ may be the same or different. ] A liquid crystal composition comprising the dichroic dye according to claim 1 . A liquid crystal element comprising a liquid crystal phase containing the liquid crystal composition according to claim 2 .

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