JP6851710B2 - Materials for electrochromic display elements - Google Patents

Description

The present invention relates to electrochromic compounds and electrochromic display devices.

Electrochromism is a phenomenon in which a redox reaction occurs reversibly by applying a voltage and the color changes reversibly. The electrochromic material exhibiting electrochromism is generally formed between two opposing electrodes, and undergoes a redox reaction in a configuration in which an ionic conductive electrolyte layer is filled between the electrodes. When a reduction reaction occurs in the vicinity of one of the two opposing electrodes, an oxidation reaction, which is a reverse reaction, occurs in the vicinity of the other electrode.

In an electrochromic display element using the electrochromic material, a device having a structure in which a transparent display device is obtained or three color-developing layers of cyan (C), magenta (M), and yellow (Y) are laminated. When constructing, it is important that it is composed of a material that has a colorless and transparent state.
As the electrochromic material, a viologen compound or the like showing an electrochromic phenomenon in which the neutral state is transparent and the color is developed in the reduced state is used. Titanium oxide is preferably used in combination with the viologen compound. Among these, it has been reported that high optical density and high contrast ratio can be maintained by using titanium oxide particles as supporting particles of the electrochromic compound in the laminated structure.

Triarylamine compounds and the like have been reported as electrochromic materials that develop color in an oxidized state while the neutral state is transparent (see, for example, Non-Patent Document 1).
Further, an electrochromic apparatus using a compound obtained by imparting a polymerizable functional group to a triarylamine-based material has been proposed (see, for example, Patent Document 1).

However, Non-Patent Document 1 discloses an electrochromic display device in which a copolymer material with a triarylamine compound and polycholine methacrylate (PCM) are laminated in a dozen or more layers. Therefore, it cannot be said that the manufacturing process of the electrochromic display element is complicated and practical disclosure, and the repetition of about 500 times is evaluated in the best configuration, but the description also suggests the light durability. Nor.
Further, Patent Document 1 has a problem that the carrier mobility is not sufficient in the polymerized film and the surface area is small, so that the film thickness needs to be increased in order to obtain a high color development density, and the response speed becomes slow. ..

Therefore, as in the case of the viologen compound, titanium oxide is used as a compound represented by the following structural formula (A) in which an adsorbent group such as phosphonic acid is added to a triarylamine compound that increases the surface area and improves the response rate. A method of supporting and using the compound on such particles has been proposed (see, for example, Non-Patent Document 2).
However, in Non-Patent Document 2, although the response speed is improved, the compound represented by the structural formula (A) is insufficient in repeatability such as reverse voltage resistance at the time of decolorization and light durability. Met.
[Structural formula (A)]

Further, Non-Patent Document 3 describes TPD-3 represented by the following structural formula (B). However, Non-Patent Document 3 only discloses the use of organic electroluminescence as an injection layer, and does not disclose any characteristics when it is used as an electrochromic material.
[Structural formula (B)]

Therefore, an object of the present invention is to provide an electrochromic compound capable of stable operation and excellent in response speed, repeatability, and light resistance.

（ただし、前記一般式（Ｉ）中、Ｒ_１からＲ_２８は、それぞれ独立して、水素原子、ハロゲン原子、一価の有機基、或いは水酸基に対して直接的に又は間接的に結合することができる官能基を示し、少なくとも一つは、前記水酸基に対して直接的に又は間接的に結合することができる官能基を示す） The electrochromic compound of the present invention as a means for solving the above-mentioned problems is a compound represented by the following general formula (I).
[General formula (I)]

(However, in the general formula (I), R ₁ to R ₂₈ are independently bonded to a hydrogen atom, a halogen atom, a monovalent organic group, or a hydroxyl group, either directly or indirectly. Indicates a functional group capable of binding, at least one of which indicates a functional group capable of directly or indirectly binding to the hydroxyl group).

According to the present invention, it is possible to provide an electrochromic compound which can solve the above-mentioned problems in the past, can achieve the above-mentioned object, can perform stable operation, and is excellent in response speed, repeatability, and light resistance. it can.

FIG. 1 is a schematic view showing an example of the electrochromic display device of the present invention. Is. FIG. 2 is a schematic view showing another example of the electrochromic display device of the present invention. FIG. 3 is a schematic view showing another example of the electrochromic display device of the present invention. FIG. 4 is an absorption spectrum in a decolorized state and a colored state of the display electrode forming the electrochromic display layer produced in Example 5.

(Electrochromic compound)
The electrochromic compound of the present invention is represented by the following general formula (I).
[General formula (I)]

However, in the general formula (I), R ₁ to R ₂₈ may be independently or indirectly bonded to a hydrogen atom, a halogen atom, a monovalent organic group, or a hydroxyl group. A functional group capable of being formed, and at least one of which is a functional group capable of directly or indirectly binding to the hydroxyl group.

Examples of the halogen atom include fluorine, chlorine, bromine, iodine and the like.

Examples of the monovalent organic group include a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a carbonyl group, an amide group, an aminocarbonyl group, a sulfonic acid group, a sulfonyl group, a sulfonamide group, an aminosulfonyl group and an amino group. , Alkyl group, alkenyl group, alkynyl group, aryl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, heteroaryl group and the like. These may have substituents.

Examples of those that may have the substituent include an alkoxycarbonyl group that may have a substituent, an aryloxycarbonyl group that may have a substituent, and a substituent. A good alkylcarbonyl group, an arylcarbonyl group which may have a substituent, a monoalkylaminocarbonyl group which may have a substituent, a dialkylaminocarbonyl group which may have a substituent, and a substituent. A carbonyl group which may have a substituent such as a monoarylaminocarbonyl group which may have a substituent and a diarylaminocarbonyl group which may have a substituent; an alkoxysulfonyl which may have a substituent. It has a group, an aryloxysulfonyl group that may have a substituent, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, a sulfonamide group, and a substituent. Monoalkylaminosulfonyl group which may have a substituent, dialkylaminosulfonyl group which may have a substituent, monoarylaminosulfonyl group which may have a substituent, and diaryl which may have a substituent. A sulfonyl group that may have a substituent such as an aminosulfonyl group; a monoalkylamino group that may have a substituent, an alkylamino group such as a dialkylamino group that may have a substituent; An alkyl group which may have a group, an alkenyl group which may have a substituent; an alkynyl group which may have a substituent; an aryl group which may have a substituent; An alkoxy group which may have a substituent; an aryloxy group which may have a substituent; an alkylthio group which may have a substituent; an arylthio group which may have a substituent; Examples thereof include a heteroaryl group which may be used.

Among these, an alkyl group having 1 or more carbon atoms, an alkenyl group having 2 or more carbon atoms, an alkynyl group having 2 or more carbon atoms, an aryl group having 6 or more carbon atoms, a heteroaryl group having 2 or more carbon atoms, an alkoxy group, and an aryloxy A group and a heteroaryloxy group are preferable.

As the alkyl group having 1 or more carbon atoms, for example, a linear or branched chain or a cyclic alkyl group having 1 or more carbon atoms and 30 or less carbon atoms is preferable, and an alkyl having 1 or more carbon atoms and 18 or less carbon atoms is preferable from the viewpoint of availability of raw materials. Groups are more preferred.
Examples of the alkyl group having 1 or more carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, an isobutyl group, a pentyl group, a hexyl group, a heptyl group, an ethylhexyl group, an octyl group, a decyl group and a dodecyl group. Examples thereof include a group, a 2-butyloctyl group, an octadecyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and an adamantyl group.

As the alkenyl group having 2 or more carbon atoms, for example, a linear or branched chain or a cyclic alkenyl group having 2 or more carbon atoms and 30 or less carbon atoms is preferable as in the alkyl group having 1 or more carbon atoms, and the alkenyl group has 1 or more carbon atoms. 18 or less alkenyl groups are more preferred.
The alkenyl group having 2 or more carbon atoms is a substituent obtained by removing two arbitrary hydrogens of the alkyl group having 1 or more carbon atoms, and is, for example, a vinyl group (ethenyl group), a propenyl group, a butenyl group, or a pentanyl group. , Hexenyl group, heptanyl group, octenyl group, decenyl group, dodecenyl group, octadecenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group and the like.

As the alkynyl group having 2 or more carbon atoms, for example, a linear or branched chain or a cyclic alkynyl group having 2 or more carbon atoms and 30 or less carbon atoms is preferable as in the alkyl group having 1 or more carbon atoms, and the alkynyl group has 1 or more carbon atoms and 18 carbon atoms. The following alkynyl groups are more preferred.
The alkynyl group having 2 or more carbon atoms is a substituent obtained by removing 4 arbitrary hydrogens of the alkyl group having 1 or more carbon atoms. For example, an ethynyl group, a propynyl group, a butynyl group, a pentynyl group, a hexynyl group, or a heptynyl group. Examples thereof include a group, an octynyl group, a decynyl group, a dodecynyl group, an octadecynyl group and the like.

As the aryl group having 6 or more carbon atoms, for example, an aryl group having 6 or more carbon atoms and 18 or less carbon atoms is preferable.
Examples of the aryl group having 6 or more carbon atoms include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a p-chlorophenyl group, a p-fluorophenyl group, a p-trifluorophenyl group and a naphthyl. Examples include a group, a biphenyl group, an anthryl group, a phenanthryl group, a pyrenyl group and the like.

As the heteroaryl group having 2 or more carbon atoms, for example, a heteroaryl group having 2 or more carbon atoms and 12 or less carbon atoms is preferable.
Examples of the constituent elements of the heteroaryl group having 2 or more carbon atoms include a nitrogen atom, a sulfur atom, an oxygen atom, a silicon atom, and a selenium atom. Among these, it is preferable that any one selected from a nitrogen atom, a sulfur atom, and an oxygen atom is contained.
Examples of the heteroaryl group having 2 or more carbon atoms include a monocyclic heteroaryl group and a polycyclic heteroaryl group.
Examples of the monocyclic heteroaryl group include a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a tetrazine, a thiophene ring, a furan ring, a pyrrole, an imidazole, a pyrazole, a thiazole ring, an oxazole ring, an isoxazole, and an oxazole. Examples include a ring, a triazine ring, a tetrazole ring, and a triazole ring.
Examples of the polycyclic heteroaryl group include a quinoline group, an isoquinolin group, a quinarizone group, a phthalazine group, an indole group, a benzothiophene group, a benzofuran group, a benzimidazole group, a benzothiodiazol group, an aclysine group and a phenoxazine group. , Phenothiazine group, carbazole group, benzodithiophene group, benzodifuran group and the like.

Examples of the functional group that can be directly or indirectly bonded to the hydroxyl group include a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, a sulfonyl group, a silyl group, and a silanol group. Among these, a phosphonic acid group, a phosphoric acid group, and a carboxylic acid group are preferable, and a phosphonic acid group is more preferable, from the viewpoints of ease of synthesis, adsorptivity to supporting particles, and stability of the compound.
Examples of the phosphonic acid group include methyl phosphonic acid group, ethyl phosphonic acid group, propyl phosphonic acid group, hexyl phosphonic acid group, octyl phosphonic acid group, decyl phosphonic acid group, dodecyl phosphonic acid group, octadecyl phosphonic acid group, and benzyl phosphon. Examples thereof include an acid group, a phenylethyl phosphonic acid group, a phenylpropyl phosphonic acid group, and a biphenyl phosphonic acid group.
Examples of the phosphate group include methyl phosphate group, ethyl phosphate group, propyl phosphate group, hexyl phosphate group, octyl phosphate group, decyl phosphate group, dodecyl phosphate group, octadecyl phosphate group, benzyl phosphate group and phenyl. Examples thereof include an ethyl phosphate group, a phenylpropyl phosphate group, and a biphenyl phosphate group.
Examples of the carboxylic acid group include a methylcarboxylic acid group, an ethylcarboxylic acid group, a propylcarboxylic acid group, a hexylcarboxylic acid group, an octylcarboxylic acid group, a decylcarboxylic acid group, a dodecylcarboxylic acid group, an octadecylcarboxylic acid group, and a benzyl. Examples thereof include a carboxylic acid group, a phenylethyl carboxylic acid group, a phenylpropyl carboxylic acid group, a biphenyl carboxylic acid group, a 4-propyl phenyl carboxylic acid group, and a 4-propyl biphenyl carboxylic acid group.
Examples of the sulfonyl group include methyl sulfonyl group, ethyl sulfonyl group, propyl sulfonyl group, hexyl sulfonyl group, octyl sulfonyl group, decyl sulfonyl group, dodecyl sulfonyl group, octadecyl sulfonyl group, benzyl sulfonyl group, phenyl ethyl sulfonyl group and phenyl propi. Examples thereof include a rusulfonyl group and a biphenylsulfonyl group.
Examples of the silyl group include a methylsilyl group, an ethylsilyl group, a propylsilyl group, a hexylsilyl group, an octylsilyl group, a decylsilyl group, a dodecylsilyl group, an octadecylsilyl group, a benzylsilyl group, a phenylethylsilyl group and a phenylpropylsilyl group. , Biphenylsilyl group and the like.
Examples of the silanol group include methylsilanol group, ethylsilanol group, propylsilanol group, hexylsilanol group, octylsilanol group, decylsilanol group, dodecylsilanol group, octadecylsilanol group, benzylsilanol group, phenylethylsilanol group and phenylpropi. Examples thereof include a lucilanol group and a biphenylsilanol group.

As the functional group that can be directly or indirectly bonded to the hydroxyl group, for example, an alkyl group having 1 or more carbon atoms; an aryl group having 6 or more carbon atoms; It is preferably substituted at the terminal of an aryl group substituted with an alkyl group having 7 or more carbon atoms, and more preferably substituted at the terminal of an alkyl group.

When a functional group that can be directly or indirectly bonded to the hydroxyl group is indirectly bonded to the hydroxyl group, it is preferable that the functional group is bonded via an alkyl group having at least 2 or more carbon atoms.

As the electrochromic compound represented by the general formula (I), for example, a compound represented by the following general formula (II) is preferably mentioned.

[General formula (II)]

However, in the general formula (II), _{at least one selected from R 1} to R ₄ and R ₁₃ to R ₂₈ has a functional group capable of directly or indirectly binding to the hydroxyl group. Shown. Among these, it is preferable _{that at least one selected from the above R 1} to R ₄ is represented by a functional group capable of directly or indirectly binding to the hydroxyl group, and R ₁ to R ₄ are represented by functional groups. A functional group capable of directly or indirectly binding to a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, or the hydroxyl group. More preferably, it is represented by a group and at least one of R ₁ to R ₄ is represented by a functional group capable of directly or indirectly binding to the hydroxyl group.
The same applies to the general formula (I) except for _{R 1} to R ₄ and R ₁₃ to R _28.

The substitution position of the functional group that can be directly or indirectly bonded to the hydroxyl group is not the biphenyl skeleton located at the center of the structure of the compound, but R ₁ to R ₄ and R ₁₃ to R. _{By limiting to at least one selected from 28,} it is possible to introduce a functional group capable of directly or indirectly binding to a hydroxyl group in the final step in the synthesis of the compound, and the synthesis becomes more efficient. It will be convenient. Further, when introduced into the biphenyl skeleton located at the center of the structure of the compound, functional groups increase in the minor axis direction, so that the crystallinity is lower than when introduced in the major axis direction, and the target compound can be handled. It may be difficult to do.

When _{at least one selected from R 1} to R ₄ is represented by a functional group capable of directly or indirectly binding to the hydroxyl group, the para position of the triphenylamine skeleton is relative to the hydroxyl group. Since a functional group that can be directly or indirectly bonded is introduced, it is preferable from the viewpoint of increasing the crystallinity and stability of the compound.

As the electrochromic compound represented by the general formula (I), for example, a compound represented by the following general formula (III) is more preferably mentioned.
[General formula (III)]

However, in the general formula (III), X is a halogen atom, an alkyl group having 1 or more carbon atoms, an alkenyl group having 2 or more carbon atoms, an alkynyl group having 2 or more carbon atoms, an aryl group having 6 or more carbon atoms, and a carbon number of carbon atoms. Indicates a functional group capable of directly or indirectly binding to two or more heteroaryl groups, alkoxy groups, aryloxy groups, heteroaryloxy groups, or hydroxyl groups. )
Other than the X, it is the same as the general formula (I).

Since the para-position of the triphenylamine skeleton in the general formula (III) has a high electron density and high reactivity, it causes unexpected side reactions such as dimerization, cyclization, and decomposition reaction in the redox state. The possibility is very high. Therefore, it is preferable that the para position of the triphenylamine skeleton is substituted with the X other than the hydrogen atom.

As the electrochromic compound represented by the general formula (I), for example, a compound represented by the following general formula (IV) and the like are more preferably mentioned.
[General formula (IV)]

However, in the general formula (IV), the Y represents a functional group capable of directly or indirectly bonding to an alkyl group, an alkoxy group, or a hydroxyl group, and at least one of the Ys is Indicates a functional group that can be directly or indirectly bonded to a hydroxyl group. The alkyl group and the alkoxyl group themselves have low reactivity and can be preferably used because they do not cause a significant change in the stability and color tone of the compound represented by the general formula (IV).
Except for Y, the same as the general formula (I).

The number of functional groups that can be directly or indirectly bonded to the hydroxyl group of Y is preferably 1 or more and 2 or less. If at least one of the functional groups is introduced, the molecule can be bonded to the hydroxyl group, and if two or less of the functional groups are introduced, the molecule tends to be a symmetric molecule, and the molecule is synthesized and synthesized. It is advantageous in terms of purification, and its polarity makes purification difficult, stability of the main skeleton, and overdoping of the donor triphenylamine, for example when a phosphonic acid group is introduced. Electrical characteristics such as coloring during decolorization and deterioration during driving are not impaired.

In the general formula (IV), R ₉ to R ₁₂ can be the same as those in the general formula (I) from R _{9 to R 12} , but it is preferable that all of them are hydrogen atoms. The general formula (V) in which _{R 9} to R _{12 are all hydrogen is shown below.}

[General formula (V)]

In the general formula (V), _{R 28} from _{R 8,} and _{R 13} from _{R 5} is the same as _{R 8,} and _{R 13} from _{R 28} from _{R 5} in the formula (I), Y Is the same as Y in the general formula (IV).

_{When R 9} to R ₁₂ in the general formula (IV) are all hydrogen atoms, for example, when a bulky substituent such as an alkyl group such as a methyl group or a halogen atom such as a chlorine atom is introduced. As described above, it is possible to prevent the biplane angle of biphenyl from becoming large and to suppress the decrease in the stability of the compound during redox.

As the electrochromic compound represented by the general formula (I), for example, a compound represented by the following general formula (VI) and the like are particularly preferably mentioned.
[General formula (VI)]

However, the general formula (VI), Z is a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy _{group, R 28} from _{R 13,} like the _{R 13} in the general formula (I) and _{R 28} And Y is the same as Y in the general formula (IV).

Hereinafter, the structures of preferable compounds of the present invention will be specifically exemplified, but the structure is not limited to these compounds.

<Example compound 1>

<Example compound 2>

<Example compound 3>

<Example compound 4>

<Example compound 5>

<Example compound 6>

<Example compound 7>

<Example compound 8>

<Example compound 9>

<Example compound 10>

<Example compound 11>

<Example compound 12>

<Example compound 13>

Ｅｔは、エチル基を示す。 <Example compound 14>

Et represents an ethyl group.

Ｅｔは、エチル基を示す。 <Example compound 15>

Et represents an ethyl group.

<Example compound 16>

<Example compound 17>

<Example compound 18>

<Example compound 19>

ただし、Ｍｅは、メチル基を示す。 <Example compound 20>

However, Me represents a methyl group.

ただし、Ｍｅは、メチル基を示す。 <Example compound 21>

However, Me represents a methyl group.

-Manufacturing method-
From the viewpoint of availability and toxicity of the compound, the electrochromic compound includes, for example, a biphenyl compound represented by the following general formula (VII), which is a halogen compound, and an amine compound represented by the general formula (VIII), for example. For example, a metal catalyst such as a palladium catalyst, a nickel catalyst, or a copper catalyst and, if necessary, a base are subjected to a cross-coupling reaction between carbon and nitrogen in an appropriate solvent, and is represented by the following general formula (IX). Diamine or a triamine skeleton represented by the following general formula (X) can be obtained.

ただし、前記一般式（ＶＩＩ）中、Ｒ_５からＲ_１２は、前記一般式（Ｉ）中のＲ_５からＲ_１２と同様であり、Ｈａｌはハロゲン原子又はトリフラート基を示す。 [General formula (VII)]

However, the general formula (VII), _{R 5 to R 12} are the same as _{R 5 to R 12} in the general formula (I), Hal represents a halogen atom or a triflate group.

ただし、前記一般式（ＶＩＩＩ）中、Ｒ_１、及びＲ_１３からＲ_１６は、前記一般式（Ｉ）中のＲ_１、及びＲ_１３からＲ_１６と同様である。 [General formula (VIII)]

In the general formula (VIII), _{R 1,} and _{R 16} from _{R 13} is, _{R 1} in the general formula (I), and is similar to the _{R 13} and _{R 16.}

ただし、前記一般式（ＩＸ）中、Ｒ_５からＲ_１２は、前記一般式（ＶＩＩ）中のＲ_５からＲ_１２と同様であり、Ｒ_１、及びＲ_１３からＲ_１６は、前記一般式（ＶＩＩＩ）中のＲ_１、及びＲ_１３からＲ_１６と同様である。 [General formula (IX)]

In the general formula (IX), _{R 5 to R 12} are the same as _{R 5 to R 12} in the general formula (VII), _{R 1,} and from _{R 13 R 16} is the formula ( It is the same as R ₁ and R ₁₃ to R _{16 in} VIII).

ただし、前記一般式（Ｘ）中、Ｒ_５からＲ_１２は、前記一般式（ＶＩＩ）中のＲ_５からＲ_１２と同様であり、Ｒ_１、及びＲ_１３からＲ_１６は、前記一般式（ＶＩＩＩ）中のＲ_１、及びＲ_１３からＲ_１６と同様である。 [General formula (X)]

In the general formula (X), _{R 5 to R 12} are the same as _{R 5 to R 12} in the general formula (VII), _{R 1,} and from _{R 13 R 16} is the formula ( It is the same as R ₁ and R ₁₃ to R _{16 in} VIII).

Next, the amine compound represented by the general formula (IX) or (X) is similarly cross-coupled with the aromatic halide or triflate compound to be represented by the general formula (I). The electrochromic compound of the present invention can be obtained.

A functional group capable of directly or indirectly binding to the hydroxyl group may be introduced into an aromatic halide or a triflate, or may be introduced after coupling.

Examples of the halogen atom include a chlorine atom, a bromine atom and an iodine atom. Among these, chlorine atom and bromine atom are preferable.
As the amine compound, it is preferable to carry out a coupling reaction in the form of an amide and hydrolyze the amide after the reaction from the viewpoint of preventing the by-product of the polysubstituted product.

The base is not particularly limited, and examples thereof include a strong base.
Examples of the strong base include sodium-tert-butoxide, potassium-tert-butoxide, potassium carbonate, cesium carbonate, potassium phosphate and the like.

The solvent is not particularly limited, and examples thereof include toluene, xylene, mesitylene, dioxane, tert-butyl alcohol, tetrahydrofuran, chlorobenzene, o-dichlorobenzene, nitrobenzene, and quinoline.

Examples of the catalyst include palladium acetate, trisdibenzylideneacetone dipalladium, bisbendylideneacetone palladium, copper, copper oxide and the like. The catalyst may be combined with a suitable ligand.
Examples of the ligand include phosphorus ligands such as triphenylphosphine, tributylphosphine and tri-tert-butylphosphine; and nitrogen-based ligands such as ethylenediamine, cyclohexyldiamine, phenanthroline and bipyridyl.

Examples of the functional group that can be directly or indirectly bonded to the hydroxyl group include, in the case of phosphonic acid, the halogen after cross-coupling the aromatic halide or triflate having the alkyl halide. A phosphonate is obtained by a Michaelis-Arbuzov reaction with a triethyl phosphate on an alkyl halide. Next, the ester is hydrolyzed by reacting the phosphonate with, for example, an acid, a silane compound, or the like to obtain the desired phosphonic acid derivative.
Similar to the case of the phosphonic acid, the phosphate group, the carboxylic acid group, the sulfonyl group, the silyl group, and the silanol group can be derivatized by using a known reaction.
Examples of the acid include hydrochloric acid, sulfuric acid and the like.
Examples of the silane compound include trimethylsilyl bromide and trimethylsilyl chloride.

Purification of the crude product of the electrochromic compound obtained after the reaction can be carried out by various existing purification methods.
Examples of the purification method include solvent washing, recrystallization, column chromatography, reprecipitation, sublimation purification and the like.

(Electrochromic composition)
The electrochromic composition contains the electrochromic compound of the present invention and a conductive nanostructure or a semiconductor nanostructure that binds to or adsorbs the electrochromic compound, and has other components as necessary. It will be done.

When the electrochromic composition is used in an electrochromic display element, it exhibits a black color and is excellent in image memory, that is, a color-developed image retention characteristic.
_{When at least one selected from R 1} to R ₄ in the general formula (I) is a functional group capable of directly or indirectly binding to a hydroxyl group, for example, the electrochromic of the present invention. When the compound has a phosphonic acid, a sulfonic acid group, a phosphoric acid group, a carboxyl group, or the like as a bond or adsorption structure, the electrochromic compound is easily compounded with the nanostructure and has an electrochromic composition having excellent color image retention. It becomes a thing. The electrochromic compound may have a plurality of the phosphonic acid group, the sulfonic acid group, the phosphoric acid group, and the carboxyl group. Further, when the electrochromic compound of the present invention has a silyl group, a silanol group, etc., it is bonded to the nanostructure via a siloxane bond to strengthen the bond, thereby obtaining a stable electrochromic composition. Can be done. The siloxane bond refers to a chemical bond via a silicon atom and an oxygen atom. Further, the electrochromic composition may have a structure in which the electrochromic compound and the nanostructure are bonded via a siloxane bond, and the bonding method and form thereof are not particularly limited.

The conductive nanostructure or the semiconductor nanostructure refers to a structure having nanoscale irregularities such as nanoparticles or nanoporous structures.
Examples of the material constituting the conductive nanostructure or the semiconductor nanostructure include metal oxides and the like from the viewpoint of transparency and conductivity.
Examples of the metal oxide include titanium oxide, zinc oxide, tin oxide, zirconium oxide, cerium oxide, yttrium oxide, boron oxide, magnesium oxide, strontium titanate, potassium titanate, barium titanate, calcium titanate, and oxidation. Examples thereof include calcium, ferrite, hafnium oxide, tungsten oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, barium oxide, strontium oxide, vanadium oxide, aluminosilicate, calcium phosphate, and aluminosilicate as main components. These may be used alone or in combination of two or more. Among these, titanium oxide, zinc oxide, tin oxide, zirconium oxide, iron oxide, magnesium oxide, indium oxide, and tungsten oxide are preferable from the viewpoint of electrical properties such as electrical conductivity and physical properties such as optical properties. , Titanium oxide is more preferable. When the metal oxide or a mixture of the metal oxides is used, the response speed of color development is excellent.

As the shape of the metal oxide, fine metal oxide fine particles having an average primary particle diameter of 30 nm or less are preferable. The smaller the average primary particle size, the more the light transmittance to the metal oxide can be improved, and a shape having a large surface area per unit volume (hereinafter, referred to as “specific surface area”) is used. By having a large specific surface area, the electrochromic compound can be supported more efficiently, and multicolor display with an excellent display contrast ratio for color emission and extinction can be performed. The specific surface area of the nanostructure is not particularly limited and can be appropriately selected depending on the intended purpose, and ^{is preferably 100 m 2} / g or more.

<Electrochromic display element>
The electrochromic display element of the present invention has a first electrode, a second electrode, and an electrolyte between the first electrode and the second electrode, and the first electrode is the said. It has the electrochromic composition containing an electrochromic compound and, if necessary, other components.

-First electrode and second electrode-
Examples of the material constituting the first electrode and the second electrode include a transparent conductive substrate and the like. As the transparent conductive substrate, for example, a glass or plastic film coated with a transparent conductive thin film is preferable.

The material of the transparent conductive thin film is not particularly limited as long as it is a conductive transparent material, and can be appropriately selected depending on the intended purpose. For example, tin-doped indium oxide (hereinafter, also referred to as “ITO”). ), Indium oxide doped with fluorine (hereinafter, also referred to as "FTO"), tin oxide doped with antimony (hereinafter, also referred to as "ATO"), inorganic materials such as zinc oxide and the like can be mentioned. Among _{these, InSnO, GaZnO, SnO, In} 2 O 3, ZnO is preferable.

Furthermore, transparent carbon nanotubes and other highly conductive non-transparent materials such as Au, Ag, Pt, and Cu are formed in a fine network to improve conductivity while maintaining transparency. Electrodes may be used.
The average thickness of each of the first electrode and the second electrode is adjusted so that the electric resistance value required for the redox reaction of the electrochromic layer can be obtained.
When ITO is used as the material for the first electrode and the second electrode, the average thickness of each of the first electrode and the second electrode is preferably, for example, 50 nm or more and 500 nm or less.

As a method for producing each of the first electrode and the second electrode, a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like can be used.
The coating method of each material of the first electrode and the second electrode is not particularly limited as long as it can be coated and formed, and for example, a spin coating method, a casting method, a microgravure coating method, and a gravure coating method. , Bar coating method, roll coating method, wire bar coating method, dip coating method, slit coating method, capillary coating method, spray coating method, nozzle coating method, gravure printing method, screen printing method, flexographic printing method, offset printing method, Various printing methods such as a reverse printing method and an inkjet printing method can be used.

-Electrolyte-
The electrolyte is filled between the first electrode and the second electrode.
Examples of the electrolyte include inorganic ion salts such as alkali metal salts and alkaline earth metal salts; supporting salts such as quaternary ammonium salts, acids and alkalis, and specific examples thereof include LiClO ₄ and LiBF _4. , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ COO, KCl, NaClO ₃ , NaCl, NaBF ₄ , NaSCN, KBF ₄ , Mg (ClO ₄ ) ₂ , Mg (BF ₄ ) _{2, and the} like. These may be used alone or in combination of two or more.

An ionic liquid can also be used as the material of the electrolyte. Among these, organic ionic liquids are preferably used because they have a molecular structure that exhibits a liquid in a wide temperature range including room temperature.

As the molecular structure showing a liquid in a wide temperature range including room temperature, examples of the cationic component include N, N-dimethylimidazole salt, N, N-methylethylimidazole salt, N, N-methylpropylimidazole salt and the like. Imidazole derivatives; pyridinium derivatives such as N, N-dimethylpyridinium salt, N, N-methylpropylpyridinium salt; aliphatic quaternary ammonium salts such as trimethylpropylammonium salt, trimethylhexylammonium salt, triethylhexylammonium salt and the like can be mentioned. as the anionic component, from the viewpoint of stability in the atmosphere, it is preferable to use containing a fluorine compound, for _{^{example, BF 4 -, CF 3 SO}} 3 -, PF 4 -, (CF 3 SO 2) 2 N- ^{and the} like can be mentioned. These may be used alone or in combination of two or more.
As the material of the electrolyte, it is preferable to use an ionic liquid in which the cation component and the anion component are arbitrarily combined.

The ionic liquid may be dissolved directly in any of the photopolymerizable monomers, oligomers, and liquid crystal materials. If the solubility is poor, a solution dissolved in a small amount of solvent may be mixed with any of a photopolymerizable monomer, an oligomer, and a liquid crystal material.

Examples of the solvent include propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, and polyethylene glycol. , Alcohols, or a mixed solvent thereof and the like.

The electrolyte does not have to be a low-viscosity liquid, and can take various forms such as a gel-like, polymer-crosslinked type, and liquid crystal-dispersed type. By forming the electrolyte in the form of a gel or a solid, it is advantageous in terms of improving the strength of the device and improving the reliability.
As a solidification method, it is preferable to retain the electrolyte and the solvent in the polymer resin from the viewpoint of obtaining high ionic conductivity and solid strength.
As the polymer resin, a photocurable resin is preferable because an element can be manufactured at a low temperature and in a short time as compared with a method of thinning by thermal polymerization or evaporation of a solvent.
The average thickness of the electrolyte layer made of the electrolyte is not particularly limited and can be appropriately selected depending on the intended purpose, and is preferably 100 nm or more and 100 μm or less.

-Other parts-
The other members are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a support, an insulating porous layer, a deterioration prevention layer, and a protective layer.

--Support ---
As the support, a well-known organic material or inorganic material can be used as it is as long as it is a transparent material that can support each layer.
Examples of the support include glass substrates such as non-alkali glass, borosilicate glass, float glass, and soda lime glass; polycarbonate resin, acrylic resin, polyethylene, polyvinyl chloride, polyester, epoxy resin, melamine resin, and phenol resin. Examples thereof include a resin substrate such as a polyurethane resin and a polyimide resin.
The surface of the support may be coated with a transparent insulating layer, a UV blocking layer, an antireflection layer, or the like in order to enhance water vapor barrier property, gas barrier property, ultraviolet resistance, and visibility.

The shape of the support is not particularly limited and may be rectangular or round.
The support may be a plurality of superpositions. For example, the water vapor barrier property and the gas barrier property can be enhanced by forming a structure in which the electrochromic display element is sandwiched between two glass substrates.

--Insulating porous layer ---
The insulating porous layer has a function of separating the first electrode and the second electrode so as to be electrically insulated and holding an electrolyte.
The material of the insulating porous layer is not particularly limited as long as it is porous, and organic materials, inorganic materials having high insulating properties, durability and excellent film forming properties, and composites thereof are preferable.
Examples of the method for forming the insulating porous layer include a sintering method (polymer fine particles and inorganic particles are partially fused by adding a binder or the like to utilize pores formed between the particles), and extraction. Method (after forming a constituent layer with a solvent-soluble organic or inorganic substance and a binder that is insoluble in the solvent, the organic or inorganic substance is dissolved with a solvent to obtain pores), foaming method for foaming, good solvent and poor Examples thereof include a phase conversion method in which a solvent is manipulated to phase-separate a mixture of polymers, and a radiation irradiation method in which various types of radiation are radiated to form pores.

--Deterioration prevention layer ---
The deterioration prevention layer undergoes a chemical reaction opposite to that of the electrochromic layer made of an electrochromic composition, and the first electrode and the second electrode are corroded or deteriorated by an irreversible redox reaction in a balanced charge. Can be suppressed. The reverse chemical reaction means that the deterioration prevention layer acts as a capacitor in addition to the case of redox.

The material of the deterioration prevention layer is not particularly limited as long as it is a material that plays a role of preventing corrosion due to the irreversible redox reaction of the first electrode and the second electrode, and is appropriately selected according to the purpose. For example, antimony oxide, nickel oxide, titanium oxide, zinc oxide, tin oxide, or a conductive metal oxide containing a plurality thereof, or a semiconductor metal oxide can be used.

The deterioration prevention layer can be composed of a porous thin film that does not hinder the injection of the electrolyte. For example, conductive metal oxide fine particles such as antimony oxide, nickel oxide, titanium oxide, zinc oxide, and tin oxide or semiconductor metal oxide fine particles, for example, acrylic type, alkyd type, isocyanate type, urethane type, and epoxy type. By immobilizing the second electrode with a binder such as phenol, a suitable porous thin film satisfying the permeability of the electrolyte and the function as a deterioration prevention layer can be obtained.

When the same conductive nanostructures or semiconductor nanostructures constituting the electrochromic composition are used as the deterioration prevention layer, the first electrode, the manufacturing process of the electrochromic composition, and the second electrode are used. , And the manufacturing process of the deterioration prevention layer can be partially shared, which is preferable.

--Protective layer ---
The protective layer can protect the electrochromic display element from external stress and chemicals in the cleaning process, can prevent the leakage of the electrolyte, and further provide an electrochromic display element such as moisture and oxygen in the atmosphere. It is possible to prevent the intrusion of unnecessary things for stable operation.

The average thickness of the protective layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 μm or more and 200 μm or less.
As the material of the protective layer, for example, an ultraviolet curable resin, a thermosetting resin and the like can be used, and specific examples thereof include an acrylic resin, a urethane resin and an epoxy resin.

FIG. 1 shows a configuration example of the electrochromic display element of the present invention. As shown in FIG. 1, the electrochromic display element 8 includes a first electrode 1, a second electrode 2 provided so as to face the first electrode 1 at intervals, and the first electrode 1. It is arranged between both electrodes of one electrode and the second electrode, and includes at least an electrolyte 3 in which the electrochromic compound 4 is dissolved. In the electrochromic display element, the electrochromic compound develops and decolorizes by a redox reaction only on the electrode surface.

FIG. 2 is another configuration example of the electrochromic display device of the present invention. As shown in FIG. 2, the electrochromic display element 18 includes a first electrode 10, a second electrode 12 provided so as to face the first electrode 10 at intervals, and the first electrode 10. It includes an electrode 10 and an electrolyte 13 arranged between both electrodes of the second electrode, and a display layer 15 containing the electrochromic composition 14a is provided on the surface of the first electrode 10.

FIG. 3 is another configuration example of the electrochromic display element of the present invention. As shown in FIG. 3, the electrochromic display element 28 includes a first electrode 20, a second electrode 22 provided so as to face the first electrode 20 at intervals, and the first electrode 20. It includes an electrode 20 and an electrolyte 23 arranged between both electrodes of the second electrode, and has a display layer 25 containing the electrochromic composition 24a on the surface of the first electrode 20. Further, a white reflective layer 26 made of white particles is provided on the side of the first electrode 21 of the second electrode 22.

The electrochromic compound in the electrochromic composition has a functional group that can be directly or indirectly bonded to a hydroxyl group in the molecular structure, and directly or indirectly to the hydroxyl group. An electrochromic composition can be formed by binding to a conductive nanostructure or a semiconductor nanostructure using a functional group that can be bonded as a bonding group. Then, the electrochromic composition is provided in a layer on the first electrode 10, and the display layer 15 is formed.

-Use-
The electrochromic compound of the present invention is capable of stable operation and is excellent in response speed, repeatability, and light resistance. Therefore, for example, an electrochromic display, a large display board such as a stock price display board, or an antiglare mirror. , A dimming element such as a dimming glass, a low voltage drive element such as a touch panel type key switch, an optical switch, an optical memory, an electronic paper, an electronic album, and the like.

Hereinafter, examples and comparative examples of the present invention will be described, but the present invention is not limited to these examples. Further, "parts" and "%" shown in Examples and Comparative Examples indicate "parts by mass" and "% by mass" unless otherwise specified.

(Example 1)
<Production Example 1 of Electrochromic Compound 1>
Electrochromic compound 1 was synthesized according to the following scheme.

-Synthesis of Intermediate 1-1-
In a nitrogen-substituted flask, orthotrizine (2.12 g, 10 mmol), parabromotoluene (5.73 g, 30 mmol), sodium-tert-butoxide (8.64 g, 90 mmol), palladium acetate (67 mg, 0.3 mmol), and After adding tri-tert-butylphosphonium tetrafluoroborate (261 mg, 0.9 mmol) and replacing with argon gas, ortho-xylene (40 mL) degassed with argon gas was added, and the mixture was heated and stirred at 115 ° C. for 3 hours. It was. The reaction solution was returned to room temperature and filtered through Celite. Next, the filtrate was concentrated and purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: toluene / hexane) to obtain the following intermediate 1-1 as a pale yellow solid (yield). 2.03 g, yield 42%).

-Synthesis of Intermediate 1-2-
In a nitrogen-substituted flask, the intermediate 1-1 (2.03 g, 4.2 mmol), 1-bromo-4- (3-chloropropyl) benzene (980 mg, 4.2 mmol), sodium-tert-butoxide (1). .21 g, 12.6 mmol), palladium acetate (67 mg, 0.3 mmol), and tri-tert-butylphosphonium tetrafluoroborate (261 mg, 0.9 mmol) were added, replaced with argon gas, and then degassed with argon gas. Ortho-xylene (40 mL) was added, and the mixture was heated and stirred at 115 ° C. for 3 hours. The reaction solution was returned to room temperature and filtered through Celite. Next, the filtrate was concentrated and purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: toluene) to obtain the following intermediate 1-2 as a pale yellow solid (yield 2.). 59 g, yield 97%).

-Synthesis of Intermediate 1-3-
The intermediate 1-2 (2.59 g, 4.07 mmol) and triethyl phosphate (50 g) were placed in a nitrogen-substituted flask, and the mixture was heated and stirred at an internal temperature of 156 ° C. for 24 hours. Excess triethyl phosphate was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: toluene / ethyl acetate) to prepare a pale yellow solid, the following intermediates 1-3. Was obtained (yield 2.85 g, yield 95%).

-Synthesis of electrochromic compound 1-
The intermediate 1-3 (2.86 g) and dehydrated chloroform (50 mL) were added to the nitrogen-substituted flask, and trimethylsilyl bromide (3 mL) was added dropwise. After completion of the dropping, the mixture was stirred at room temperature for 16 hours. The solvent was distilled off under reduced pressure, methanol was added to the residue, and the residue was distilled off under reduced pressure again. This operation was repeated 3 times, the obtained solid was dispersed in methanol, and the solid was collected by filtration to obtain the following electrochromic compound 1 as a colorless solid (yield 2.60 g, yield 99%).

When the MS spectrum (ESI) of the electrochromic compound 1 was measured, the theoretical value was 680.32 and the measured value was 680.30, and it was confirmed that the electrochromic compound 1 was represented by the following structural formula (I). ..

[Structural formula (I)]

(Example 2)
<Production Example 2 of Electrochromic Compound 2>
Electrochromic compound 2 was synthesized according to the following scheme.

-Synthesis of Intermediate 2-1-
Parabromotoluene (5.73 g, 30 mmol) and sodium-tert-butoxide (8.64 g, 90 mmol), parabromotoluene (3.82 g, 20 mmol), and sodium-tert-butoxide (5.76 g, 60 mmol). Intermediate 2-1 was obtained (yield 75%) in the same manner as in the synthesis of Intermediate 1-1 in Example 1 except that the mixture was changed to.

-Synthesis of Intermediate 2-2-
Intermediate 2-1 was used in place of Intermediate 1-1, with 1-bromo-4- (3-chloropropyl) benzene (980 mg, 4.2 mmol) and 1-bromo-4- (3-chloropropyl). ) Intermediate 2-2 was obtained in the same manner as in the synthesis of Intermediate 1-1 in Example 1 except that it was changed to benzene (1,960 mg, 8.4 mmol) (yield 95%).

-Synthesis of Intermediate 2-3-
Next, Intermediate 2-3 was obtained in the same manner as in the synthesis of Intermediate 1-3 of Example 1 except that Intermediate 1-2 was changed to Intermediate 2-2 (yield 98). %).

-Synthesis of electrochromic compound 2-
Intermediate 2-3 (2.86 g) and dehydrated chloroform (50 mL) were added to the nitrogen-substituted flask, and trimethylsilyl bromide (6 mL) was added dropwise. After completion of the dropping, the mixture was stirred at room temperature for 24 hours. The solvent was distilled off under reduced pressure, methanol was added to the residue, and the residue was distilled off under reduced pressure again. This operation was repeated 3 times, the obtained solid was dispersed in methanol, and the solid was collected by filtration to obtain electrochromic compound 2 as a colorless solid (yield 2.30 g, yield 99%). When the MS spectrum of the electrochromic compound 2 was measured, the theoretical value was 788.31 and the measured value was 788.34, and it was confirmed that the electrochromic compound 2 was represented by the following structural formula (II).

[Structural formula (II)]

(Example 3)
<Production Example 3 of Electrochromic Compound 3>
Electrochromic compound 3 was synthesized according to the following scheme.

-Synthesis of Intermediate 3-1-
In a nitrogen-substituted flask, N, N'-di-p-tolylbenzidine (3.65 g, 10 mmol), 1-bromo-4- (3-chloropropyl) benzene (4.66 g, 20 mmol), sodium-tert- Butoxide (3.84 g, 40 mmol), palladium acetate (67 mg, 0.3 mmol), and tri-tert-butylphosphonium tetrafluoroborate (261 mg, 0.9 mmol) were added, replaced with argon gas, and then removed with argon gas. The vaporized ortho-xylene (40 mL) was added, and the mixture was heated and stirred at 115 ° C. for 3 hours. The reaction solution was returned to room temperature and filtered through Celite. Next, the filtrate was concentrated and purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: toluene) to obtain intermediate 3-1 as a pale yellow solid (yield 2.59 g). , Yield 95%).

-Synthesis of Intermediate 3-2-
Intermediate 3-2 was obtained in the same manner as in the synthesis of Intermediate 1-2 of Example 1 except that Intermediate 1-1 was changed to Intermediate 3-1 (yield 98%).

-Synthesis of electrochromic compound 3-
Electrochromic compound 3 was obtained in the same manner as in the synthesis of electrochromic compound 2 in Example 2 except that intermediate 2-3 was changed to intermediate 3-2 (yield 95%). When the MS spectrum of the electrochromic compound 3 was measured, the theoretical value was 760.28 and the measured value was 760.25, and it was confirmed that the electrochromic compound 3 was represented by the following structural formula (III).

[Structural formula (III)]

(Example 4)
<Production Example 4 of Electrochromic Compound 4>
Electrochromic compound 4 was synthesized according to the following scheme.

-Synthesis of Intermediate 4-1-
Intermediate 4-1 was obtained in the same manner as in the synthesis of Intermediate 1-1 in Example 1 except that parabromotoluene was changed to p-bromoanisole (yield 95%).

-Synthesis of Intermediate 4-2-
A solution of the intermediate 4-1 (5.75 g, 9.5 mmol) in dichloromethane (100 mL) was cooled to 0 ° C. in a nitrogen-substituted flask. Next, a dichloromethane solution of boron tribromide (concentration 1M, 25 mL) was added dropwise. After completion of the dropping, the solution was returned to room temperature and stirred as it was for 16 hours for reaction. After the reaction, water and dichloromethane were added, the organic layer was separated, and the aqueous layer was extracted 3 times with dichloromethane. The combined organic layers were washed with saturated brine and dried over sodium sulfate. The desiccant was filtered off, the filtrate was concentrated, and the obtained residue was dissolved in toluene / ethyl acetate (8/2), and the solution was passed through a silica gel pad (stationary phase: neutral silica gel, thickness 5 cm). This was concentrated to give Intermediate 4-2 as a pale yellow solid (yield 5.42 g, 99% yield).

-Synthesis of Intermediate 4-3-
In a nitrogen-substituted flask, the intermediate 4-2 (5.42 g, 9.41 mmol) was dissolved in dimethylformamide (50 mL), the solution was cooled to 0 ° C., and sodium hydride (480 mg, 20 mmol) was gradually added. added. Next, 1-bromo-2-chloroethane (2.86 g, 20 mmol) was added all at once, the solution was returned to room temperature, and the mixture was stirred for 16 hours for reaction. Water and ethyl acetate were added to the reacted solution, and the organic layer was separated. The aqueous layer was extracted 3 times with ethyl acetate, and the combined organic layer was washed twice with water with saturated brine and dried over sodium sulfate. The drying agent is separated by filtration, and the residue obtained by concentrating the filtrate is purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: toluene) to obtain an intermediate 4-3 as a pale yellow solid. Was obtained (yield 5.28 g, yield 80%).

-Synthesis of Intermediate 4-4-
Intermediate 4-4 was obtained in the same manner as in the synthesis of Intermediate 1-3 of Example 1 except that Intermediate 1-2 was changed to Intermediate 4-3 (yield 98%).

-Synthesis of electrochromic compound 4-
Electrochromic compound 4 was obtained in the same manner as in the synthesis of electrochromic compound 2 in Example 2 except that intermediate 2-3 was changed to intermediate 4-4 (yield 95%). When the MS spectrum of the electrochromic compound 4 was measured, the theoretical value was 792.27 and the measured value was 792.24, and it was confirmed that the electrochromic compound 4 was represented by the following structural formula (IV).

[Structural formula (IV)]

(Example 5)
<Production Example 5 of Electrochromic Compound 5>
Electrochromic compound 5 was synthesized according to the following scheme.

-Synthesis of Intermediate 5-1-
The intermediate 1-2 (3.18 g, 5 mmol), ethyl 4-hydroxybenzoate (2.08 g, 12.5 mmol, potassium carbonate (2.07 g), DMF (24 mL)) were placed in a flask and placed at 80 ° C. for 7 After stirring for hours, water and ethyl acetate were added after cooling to room temperature, the organic layer was separated, and the aqueous layer was extracted 3 times with ethyl acetate. The combined organic layer was washed with saturated brine, followed by washing. It was dried over sodium sulfate. The concentrated residue was purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: hexane / toluene → toluene) to obtain Intermediate 5-1 as a colorless solid. (Yield 3.65 g, yield 95%).

-Synthesis of electrochromic compound 5-
The intermediate 5-1 (1.8 g, 2.35 mmol), THF (90 mL), methanol (30 mL), water (30 mL) and lithium hydroxide monohydrate (296 mg, 7.06 mmol) were placed in a flask. The mixture was stirred at 90 ° C. for 3 hours. Next, after cooling to room temperature, 1 M hydrochloric acid (50 mL) was added, the precipitated solid was collected by filtration, washed with water and subsequently with hexane, and dried under vacuum to obtain electrochromic compound 5 as a colorless solid. Obtained (yield 1.48 g, yield 84%). When the MS spectrum of the electrochromic compound 5 was measured, the theoretical value was 736.37 and the measured value was 736.44, and it was confirmed that the electrochromic compound 5 was represented by the following structural formula (V).

[Structural formula (V)]

(Example 6)
<Production Example 6 of Electrochromic Compound 6>
Electrochromic compound 6 was synthesized according to the following scheme.

-Synthesis of Intermediate 6-1-
Intermediate 2-2 (1.54 g, 2.2 mmol), ethyl 4-hydroxybenzoate (1.83 g, 11.0 mmol, potassium carbonate (1.82 g), DMF (24 mL)) were placed in a flask and placed at 80 ° C. The mixture was stirred for 7 hours. Then, after cooling to room temperature, water and ethyl acetate were added, the organic layer was separated, and the aqueous layer was extracted 3 times with ethyl acetate. The combined organic layer was washed with saturated brine, and continued. And dried with sodium sulfate. The concentrated residue was purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: toluene → toluene / ethyl acetate) to form an intermediate 6-1 as a colorless solid. Was obtained (yield 1.70 g, yield 81%).

-Synthesis of electrochromic compound 6-
The intermediate 6-1 (1.68 g, 1.76 mmol), THF (90 mL), methanol (30 mL), water (30 mL), and lithium hydroxide monohydrate (441 mg, 10.53 mmol) were placed in a flask. The mixture was stirred at 90 ° C. for 3 hours. After cooling to room temperature, 1 M hydrochloric acid (50 mL) was added, and the precipitated solid was collected by filtration, washed with water and subsequently with hexane, and dried under vacuum to obtain Compound 6 as a colorless solid (yield 1). .36 g, yield 86%). When the MS spectrum of the electrochromic compound 6 was measured, it was confirmed that the theoretical value was 900.41 and the measured value was 900.50, and that the electrochromic compound 6 was represented by the following structural formula (VI).

[Structural formula (VI)]

(Example 7)
<Production Example 7 of Electrochromic Compound 7>
Electrochromic compound 7 was synthesized according to the following scheme.

-Synthesis of Intermediate 7-1-
Flask of Intermediate 2-2 (1.54 g, 2.2 mmol), ethyl-4'-hydroxy-4-biphenylcarboxylic acid (2.66 g, 11.0 mmol, potassium carbonate (1.82 g), DMF (24 mL)) Then, after cooling to room temperature, water and ethyl acetate were added, the organic layer was separated, and the aqueous layer was extracted 3 times with ethyl acetate. The combined organic layer was saturated. The mixture was washed with saline and then dried with sodium sulfate. The concentrated residue was purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: toluene → toluene / ethyl acetate) to be a colorless solid. As an intermediate 7-1 was obtained (yield 2.07 g, yield 85%).

-Synthesis of electrochromic compound 7-
The intermediate 7-1 (2.07 g, 1.87 mmol), THF (90 mL), methanol (30 mL), water (30 mL), and lithium hydroxide monohydrate (441 mg, 10.53 mmol) were placed in a flask. The mixture was stirred at 90 ° C. for 3 hours. Next, after cooling to room temperature, 1 M hydrochloric acid (50 mL) was added, the precipitated solid was collected by filtration, washed with water and subsequently with hexane, and dried under vacuum to obtain electrochromic compound 7 as a colorless solid. Obtained (yield 1.57 g, yield 80%). When the MS spectrum of the electrochromic compound 7 was measured, the theoretical value was 1052.48 and the measured value was 1052.55, and it was confirmed that the electrochromic compound 7 was represented by the following structural formula (VII).

[Structural formula (VII)]

(Example 8)
<Production Example 8 of Electrochromic Compound 8>
Electrochromic compound 8 was synthesized according to the following scheme.

In a flask, the intermediate 2-1 (3.92 g, 10 mmol), methyl 3- (4-bromophenyl) propionate (4.86 g, 20 mmol), sodium-tert-butoxide (3.84 g, 40 mmol), palladium acetate. (67 mg, 0.3 mmol) and tri-tert-butylphosphonium tetrafluoroborate (261 mg, 0.9 mmol) were added, replaced with argon gas, and then orthoxylene (40 mL) degassed with argon gas was added. Heating and stirring were performed at 115 ° C. for 3 hours. The reaction solution was returned to room temperature and filtered through Celite. Next, the filtrate was concentrated and purified by silica gel column chromatography (stationary phase: neutral silica gel, mobile phase: toluene) to obtain intermediate 8-1 as a pale yellow solid (yield 5.23 g). , Yield 73%).

-Synthesis of electrochromic compound 8-
The intermediate 8-1 (1.43 g, 2 mmol), THF (90 mL), methanol (30 mL), water (30 mL), and lithium hydroxide monohydrate (441 mg, 10.53 mmol) were placed in a flask at 90 ° C. Was stirred for 3 hours. Next, after cooling to room temperature, 1 M hydrochloric acid (50 mL) was added, and the precipitated solid was collected by filtration, washed with water and subsequently with hexane, and dried under vacuum to obtain Compound 8 as a colorless solid. (Yield 1.18 g, yield 86%). When the MS spectrum of the electrochromic compound 8 was measured, the theoretical value was 688.83 and the measured value was 688.88, and it was confirmed that the electrochromic compound 8 was represented by the following structural formula (VIII).

[Structural formula (VIII)]

(Example 9)
<Production Example 1 of Electrochromic Display Element 1>
-Preparation of the first electrode and electrochromic layer-
Titanium oxide nanoparticle dispersion (trade name:) on a glass substrate (40 mm × 40 mm, thickness: 0.7 mm, ITO film thickness: about 100 nm) with tin-doped indium (ITO) conductive film as the first electrode. SP210, manufactured by Showa Denko Ceramics Co., Ltd., average particle size: about 20 nm) was applied by a spin coating method and annealed at 120 ° C. for 15 minutes to form a titanium oxide particle film. A 2% by mass dimethylformamide (DMF) solution containing the example compound 1 prepared in Example 1 was applied to the titanium oxide particle film as a coating solution by a spin coating method, and annealed at 120 ° C. for 10 minutes. An electrochromic layer having an average thickness of 1.0 μm was formed by adsorbing the electrochromic compound of Example Compound 1 on the surface of titanium oxide particles.

-Formation of deterioration prevention layer on the second electrode-
A glass substrate with ITO conductive film as the second electrode (40 mm × 40 mm, thickness: 0.7 mm, ITO film thickness: about 100 nm), and titanium oxide nanoparticle dispersion liquid as a deterioration prevention layer (trade name: SP210, Showa Titanium Co., Ltd.) A nanostructured semiconductor material made of a titanium oxide particle film having an average thickness of 1.0 μm was formed by applying a company-made product (average particle size: about 20 nm) by a spin coating method and annealing at 120 ° C. for 15 minutes. ..

-Manufacture of electrochromic display element 1-
1-Hydroxy-cyclohexyl-phenyl-ketone (trade name: IRGACURE184, manufactured by BASF Japan Co., Ltd.) 5 parts by mass, polyethylene glycol diacrylate (trade name: PEG400DA, manufactured by Nippon Kayaku Co., Ltd.) 100 parts by mass, and 1-ethyl An electrolyte solution consisting of 50 parts by mass of -3-methylimidazolium tetracyanoborate (manufactured by Merck) was obtained. 30 mg of the obtained electrolyte solution was measured with a micropipette and dropped onto the glass substrate with an ITO conductive film having the deterioration prevention layer. A glass substrate with an ITO conductive film having an electrochromic layer was laminated on the glass substrate so as to have a lead-out portion of the electrode, and a bonded element was manufactured. The bonded element was irradiated with a UV (wavelength 250 nm) irradiator (trade name: SPOT CURE, manufactured by Ushio, Inc.) at 10 mW for 60 seconds. From the above, the electrochromic display element 1 was manufactured.

<Response speed>
The produced electrochromic display element 1 was colored by applying a voltage of -2V for 1 second. This is irradiated with deuterium tungsten halogen light (trade name: DH-2000, manufactured by Ocean Optics Co., Ltd.), the transmitted light is detected by a spectrometer (trade name: USB4000, manufactured by Ocean Optics Co., Ltd.), and the transmitted spectrum is detected. It was measured. The wavelength at which the transmittance in the visible region (400 nm or more and 800 nm or less) at that time was minimized was defined as λmax. The transmittance at that time was evaluated according to the following criteria. The results are shown in Table 1.
[Evaluation criteria]
◯: When the transmittance of λmax is less than 30% ×: When the transmittance of λmax is 30% or more

<Repeat durability>
With respect to the produced electrochromic element 1, the decoloring drive at -2V for 5 seconds and at + 1.5V for 5 seconds was repeated 500 times. The absorption maximum in the visible region (400 nm or more and 800 nm or less) at that time was defined as λmax. The change in absorbance at that time was measured with a spectrometer (trade name: USB4000, manufactured by Ocean Optics Co., Ltd.) and evaluated according to the following criteria. The results are shown in Table 1.
-Evaluation criteria-
⊚: When the absorbance of λmax is 90% or more compared to the initial state ○: When the absorbance of λmax is 80% or more and less than 90% compared to the initial state Δ: The absorbance of λmax is 50% compared to the initial state When it is less than 80% ×: When the absorbance of λmax is less than 50% compared to the initial state

<Light resistance>
The produced electrochromic element 1 was repeatedly driven to bleach and bleach at -2V for 5 seconds and at + 1.5V for 5 seconds 500 times, during which time it was irradiated with visible light (filter; UV, IR, heat ray cut: light intensity; 50,000Lx). Then, the change in absorbance of λmax before and after irradiation with visible light was measured with a spectrometer (trade name: USB4000, manufactured by Ocean Optics Co., Ltd.), and the light resistance was evaluated according to the following criteria. The results are shown in Table 1.
-Evaluation criteria-
◯: Absorbance of λmax after irradiation is 80% or more compared with λmax before irradiation Δ: Absorbance of λmax after irradiation is 50% or more and less than 80% compared with λmax before irradiation ×: λmax after irradiation Absorbance is less than 50% compared to λmax before irradiation

(Examples 10 to 29)
The electrochromic display elements 2 to 29 of Examples 10 to 29 are the same as in Example 9 except that the electrochromic compound 1 shown in the exemplary compound 1 is changed to the electrochromic compound shown in the exemplary compounds shown in Table 1. 21 was prepared. Response speed, repeatability, and light resistance were evaluated in the same manner as in Example 9. The results are shown in Table 1.

(Comparative Example 1)
The electrochromic compound 1 of the exemplary compound 1 was described in Org. Electron. 2014, 15, 428-434. The electrochromic display device of Comparative Example 1 was produced in the same manner as in Example 9 except that the compound was changed to the compound represented by the following structural formula (IX) described in. Response speed, repeatability, and light resistance were evaluated in the same manner as in Example 9. The results are shown in Table 1.

[Structural formula (IX)]

(Comparative Example 2)
The electrochromic display device of Comparative Example 2 was produced in the same manner as in Example 9 except that the electrochromic compound 1 of Exemplified Compound 1 was changed to the compound represented by the following structural formula (X). Response speed, repeatability, and light resistance were evaluated in the same manner as in Example 9. The results are shown in Table 1.

[Structural formula (X)]

(Comparative Example 3)
The electrochromic display device of Comparative Example 3 was produced in the same manner as in Example 9 except that the electrochromic compound 1 of Exemplified Compound 1 was changed to the compound represented by the following structural formula (XI). Response speed, repeatability, and light resistance were evaluated in the same manner as in Example 9. The results are shown in Table 1.

[Structural formula (XI)]

(Comparative Example 4 )
50 parts by mass of the following structural formula (XIII) on a glass substrate (40 mm × 40 mm, thickness: 0.7 mm, ITO film thickness: about 100 nm) with an indium oxide (ITO) conductive film doped with tin as a first electrode. , 1-Hydroxy-cyclohexyl-phenyl-ketone (trade name: IRGACURE184, manufactured by BASF Japan Co., Ltd.) 5 parts by mass, polyethylene glycol diacrylate (trade name: PEG400DA, manufactured by Nippon Kayaku Co., Ltd.) 100 parts by mass, and methyl ethyl ketone 900 An electrochromic composition composed of parts by mass was applied by a spin coating method, and irradiated with a UV (wavelength 250 nm) irradiation device (trade name: SPOT CURE, manufactured by Ushio Denki Co., Ltd.) at 10 mW for 60 seconds. From the above, the electrochromic layer was formed. The electrochromic display device of Comparative Example 4 was produced in the same manner as in Example 9 except that the electrochromic layer was changed. Response speed, repeatability, and light resistance were evaluated in the same manner as in Example 9. The results are shown in Table 1.

[Structural formula (XIII)]

From Table 1 above, in the case of Comparative Examples 1 to 4 using conventionally known comparative compounds, an element unsatisfactory in any of response speed, repeatability, and light resistance is provided, whereas the present invention provides the device. It has been found that an electrochromic device having a response speed, repeatability, and light resistance can be provided by using the electrochromic compound of.
From this, it can be seen that _{the presence or absence of substituents R 1} to R ₄ and the alkyl chain length thereof have a great influence on the electrical characteristics. In addition, it is found also that it is greatly affected by R ₅ in the presence or absence of substituent electric characteristics of R _8. Presumably, the compounds of Comparative Examples 1 to 4 have an electrically active portion remaining.

(Example 30)
-Form without supporting particles-
In Example 9-preparation of the first electrode and the electrochromic layer-, the electrochromic compound 1 synthesized in Example 1 is contained in the same manner as in Example 9 except that titanium oxide is not formed on the surface of the ITO substrate. A 2% by mass DMF solution was applied to prepare an electrochromic display device, and the response speed, repeatability, and light resistance were evaluated in the same manner as in Example 9. The results are shown in Table 2.

(Examples 31 to 50)
Examples 31 to 50 are the same as in Example 30 except that the electrochromic compound 1 shown in the exemplary compound 1 of Example 30 is changed to the electrochromic compounds 2 to 21 shown in the exemplary compounds shown in Table 2. The electrochromic display elements 31 to 50 of the above were manufactured. Response speed, repeatability, and light resistance were evaluated in the same manner as in Example 30. The results are shown in Table 2.

(Comparative Examples 5 to 7 )
The electrochromic display devices of Comparative Examples 5 to 7 were used in the same manner as in Example 30 except that the electrochromic compound 1 shown in Example Compound 1 of Example 30 was replaced with the compounds used in Comparative Examples 1 to 3. Made. Response speed, repeatability, and light resistance were evaluated in the same manner as in Example 30. The results are shown in Table 2.

From Table 2 above, in the case of Comparative Examples 5 to 7 using conventionally known comparative compounds, an element unsatisfactory in any of response speed, repeatability, and light resistance is provided, whereas the present invention provides the device. It can be seen that by using the electrochromic compound of the above, it is possible to provide an electrochromic device having a response speed, repeatability, and light resistance even when supported particles such as titanium oxide are not used.
From this, it can be seen that _{the presence or absence of substituents R 1} to R ₄ and the alkyl chain length thereof have a great influence on the electrical characteristics. In addition, it is found also that it is greatly affected by R ₅ in the presence or absence of substituent electric characteristics of R _8.

（ただし、前記一般式（Ｉ）中、Ｒ_１からＲ_２８は、それぞれ独立して、水素原子、ハロゲン原子、一価の有機基、或いは水酸基に対して直接的に又は間接的に結合することができる官能基を示し、Ｒ_１からＲ_２８のうち少なくとも一つは、前記水酸基に対して直接的に又は間接的に結合することができる官能基を示す）
＜２＞ 一般式（Ｉ）中、Ｒ_１からＲ_４から選択される少なくとも一つが、前記水酸基に対して直接的に又は間接的に結合することができる官能基を示す前記＜１＞に記載のエレクトロクロミック化合物である。
＜３＞ 一価の有機基が、アルキル基、アルケニル基、アルキニル基、アリール基、ヘテロアリール基、アルコキシ基、アリールオキシ基、又はヘテロアリールオキシ基である前記＜１＞から＜２＞のいずれかに記載のエレクトロクロミック化合物である。
＜４＞ 一般式（Ｉ）中、Ｒ_１からＲ_４における水酸基に対して直接的に又は間接的に結合することができる官能基の数が、１つ以上２つ以下である前記＜１＞から＜３＞のいずれかに記載のエレクトロクロミック化合物である。
＜５＞ 一般式（Ｉ）中、Ｒ_９からＲ_１２が、いずれも水素原子を示す前記＜１＞から＜４＞のいずれかに記載のエレクトロクロミック化合物である。
＜６＞ 一般式（Ｉ）中、Ｒ_５からＲ_８が、水素原子、ハロゲン原子、アルキル基、又はアルコキシ基を示す前記＜１＞から＜５＞のいずれかに記載のエレクトロクロミック化合物である。
＜７＞ 一般式（Ｉ）中、Ｒ_１からＲ_４が、ハロゲン原子、アルキル基、アルケニル基、アルキニル基、アリール基、ヘテロアリール基、アルコキシ基、アリールオキシ基、ヘテロアリールオキシ基、或いは前記水酸基に対して直接的に又は間接的に結合することができる官能基を示す前記＜１＞から＜６＞のいずれかに記載のエレクトロクロミック化合物である。
（ただし、前記一般式（Ｉ）中、Ｒ_１からＲ_４の少なくとも一つは、前記水酸基に対して直接的に又は間接的に結合することができる官能基を示す）
＜８＞ 水酸基に対して直接的に又は間接的に結合することができる官能基が、ホスホン酸基、リン酸基、カルボン酸基、スルホニル基、シリル基、又はシラノール基である前記＜１＞から＜７＞のいずれかに記載のエレクトロクロミック化合物である。
＜９＞ 水酸基に対して直接的に又は間接的に結合することができる官能基が、アルキル基、アリール基、又はアルキル基で置換されたアリール基を含む構造を有する前記＜１＞から＜８＞のいずれかに記載のエレクトロクロミック化合物である。
＜１０＞ 前記＜１＞から＜９＞のいずれかに記載のエレクトロクロミック化合物と、前記エレクトロクロミック化合物と結合又は吸着する導電性ナノ構造体又は半導体性ナノ構造体と、を含有することを特徴とするエレクトロクロミック組成物である。
＜１１＞ 第一の電極と、第二の電極と、前記第一の電極及び前記第二の電極の間に電解質と、を有するエレクトロクロミック表示素子であって、
前記第一の電極が、前記＜１＞から＜１０＞のいずれかに記載のエレクトロクロミック化合物を含むエレクトロクロミック組成物を有することを特徴とするエレクトロクロミック表示素子である。 Examples of aspects of the present invention are as follows.
<1> An electrochromic compound represented by the following general formula (I).
[General formula (I)]

(However, in the general formula (I), R ₁ to R ₂₈ are independently bonded to a hydrogen atom, a halogen atom, a monovalent organic group, or a hydroxyl group, either directly or indirectly. _{At least one of R 1} to R ₂₈ indicates a functional group capable of directly or indirectly binding to the hydroxyl group).
_{<2> The above <1>, wherein at least one selected from R 1} to R _{4 in the} general formula (I) represents a functional group capable of directly or indirectly binding to the hydroxyl group. It is an electrochromic compound of.
<3> Any of the above <1> to <2>, wherein the monovalent organic group is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group. It is an electrochromic compound described in the above.
<4> In the general formula (I), the number of functional groups that can be directly or indirectly bonded to the hydroxyl groups in _{R 1} to R _{4 is 1 or more and 2 or less.} To the electrochromic compound according to any one of <3>.
<5> In the general formula (I), R ₉ to R ₁₂ are the electrochromic compounds according to any one of <1> to <4>, all of which represent hydrogen atoms.
<6> In the general formula (I), R ₈ from R ₅ is a hydrogen atom, is an electrochromic compound according to any one of a halogen atom, an alkyl group, or a of an alkoxy group from <1><5> ..
<7> In the general formula (I), R ₁ to R ₄ are a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, or the above. The electrochromic compound according to any one of <1> to <6>, which exhibits a functional group capable of directly or indirectly binding to a hydroxyl group.
(However, in the general formula (I), _{at least one of R 1} to R ₄ represents a functional group capable of directly or indirectly binding to the hydroxyl group).
<8> The functional group that can be directly or indirectly bonded to the hydroxyl group is a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, a sulfonyl group, a silyl group, or a silanol group. To the electrochromic compound according to any one of <7>.
<9> The functional groups that can be directly or indirectly bonded to a hydroxyl group have a structure containing an alkyl group, an aryl group, or an aryl group substituted with an alkyl group, from <1> to <8. > Is the electrochromic compound according to any one of.
<10> It is characterized by containing the electrochromic compound according to any one of <1> to <9> and a conductive nanostructure or a semiconductor nanostructure that binds to or adsorbs to the electrochromic compound. It is an electrochromic composition.
<11> An electrochromic display element having a first electrode, a second electrode, and an electrolyte between the first electrode and the second electrode.
The first electrode is an electrochromic display device comprising an electrochromic composition containing the electrochromic compound according to any one of <1> to <10>.

Japanese Unexamined Patent Publication No. 2014-112183

Chem. Mater. 2006, 18, 5823-58259. Org. Electron. 2014, 15, 428-434. Advanced Functional Material, Vol. 18, p. 3966, 2008

4: Electrochromic compound

Claims (1)

A material for an electrochromic display device, which is one of the compounds represented by the following structural formulas.
<Example compound 1>

<Example compound 2>

<Example compound 3>

<Example compound 4>

<Example compound 5>

<Example compound 6>

<Example compound 7>

<Example compound 8>

<Example compound 9>

<Example compound 10>

<Example compound 11>

<Example compound 12>

<Example compound 13>

<Example compound 14>

Et represents an ethyl group.
<Example compound 15>

Et represents an ethyl group.
<Example compound 16>

<Example compound 17>

<Example compound 18>

<Example compound 19>

<Example compound 20>

However, Me represents a methyl group.
<Example compound 21>

However, Me represents a methyl group.

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