JP7505407B2 - Aniline Derivatives - Google Patents

Description

The present invention relates to an aniline derivative.

In organic electroluminescence (hereinafter referred to as organic EL) elements, charge transporting thin films made of organic compounds are used as the light emitting layer and charge injection layer. In particular, the hole injection layer is responsible for the exchange of charges between the anode and the hole transport layer or light emitting layer, and plays an important role in achieving low voltage operation and high brightness of the organic EL element.

Methods for forming hole injection layers are roughly divided into dry processes, such as vapor deposition, and wet processes, such as spin coating. Comparing these processes, wet processes can efficiently produce thin films with high flatness over large areas. Therefore, as organic EL displays are currently being made larger, there is a demand for hole injection layers that can be formed by wet processes.

Under these circumstances, the present inventors have developed materials that are applicable to various wet processes and that provide charge transport properties that enable excellent characteristics to be realized when applied to the hole injection layer of an organic EL element, as well as compounds that can be used in such materials (e.g., Patent Documents 1 to 3). However, with the current vigorous development of organic EL displays, there continues to be a demand for new wet process materials. In addition, there is also a strong demand for cheaper materials.

International Publication No. 2008/129947 International Publication No. 2015/050253 International Publication No. 2017/217457

The present invention has been made in consideration of the above circumstances, and aims to provide an aniline derivative that can be easily synthesized from simple raw material compounds, gives a thin film with excellent charge transport properties, and when this thin film is applied to a hole injection layer or the like, can realize an organic EL element with excellent characteristics.

As a result of extensive research into achieving the above-mentioned object, the inventors have discovered that a specific aniline derivative having an N,N,N',N'-tetra(carbazol-2-yl)-paraphenylenediamine structure in the molecule can not only be easily synthesized from inexpensive and simple 1,4-phenylenediamine and a halogenated or pseudohalogenated carbazole derivative, but also gives a thin film with excellent charge transport properties, and when this thin film is applied to a hole injection layer or the like, an organic EL element with excellent characteristics can be realized, thus completing the present invention.

［式中、各Ａｒは、互いに独立に、下記式（Ａｒ１）～（Ａｒ９）のいずれかで表される基である。

（式中、Ｒ¹～Ｒ²¹は、互いに独立に、水素原子、Ｚ¹で置換されていてもよい炭素数１～２０のアルキル基、Ｚ¹で置換されていてもよい炭素数２～２０のアルケニル基、Ｚ¹で置換されていてもよい炭素数２～２０のアルキニル基、Ｚ²で置換されていてもよい炭素数６～２０のアリール基又はＺ²で置換されていてもよい炭素数２～２０のヘテロアリール基であり、
Ｚ¹は、ハロゲン原子、ニトロ基、シアノ基、Ｚ³で置換されていてもよい炭素数６～２０のアリール基又はＺ³で置換されていてもよい炭素数２～２０のヘテロアリール基であり、
Ｚ²は、ハロゲン原子、ニトロ基、シアノ基、Ｚ³で置換されていてもよい炭素数１～２０のアルキル基、Ｚ³で置換されていてもよい炭素数２～２０のアルケニル基又はＺ³で置換されていてもよい炭素数２～２０のアルキニル基であり、
Ｚ³は、ハロゲン原子、ニトロ基又はシアノ基である。）］
２．Ａｒが、全て同じ基である１のアニリン誘導体。
３．Ａｒが、式（Ａｒ１）～（Ａｒ５）のいずれかで表される基である２のアニリン誘導体。
４．Ａｒが、式（Ａｒ１）で表される基である３のアニリン誘導体。
５．触媒の存在下、パラフェニレンジアミンと下記式（Ｎ１）で表されるカルバゾール誘導体とを反応させる、１のアニリン誘導体の製造方法。

（式中、Ａｒは、前記と同じであり、Ｘは、ハロゲン原子又は擬ハロゲン基である。） Accordingly, the present invention provides the following aniline derivatives:
1. An aniline derivative represented by the following formula (1):

In the formula, each Ar is independently a group represented by any one of the following formulae (Ar1) to (Ar9):

(In the formula, R ¹ to R ²¹ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with Z ¹ , an alkenyl group having 2 to 20 carbon atoms which may be substituted with Z ¹ , an alkynyl group having 2 to 20 carbon atoms which may be substituted with Z ¹ , an aryl group having 6 to 20 carbon atoms which may be substituted with Z ² , or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with Z ² ;
^Z1 is a halogen atom, a nitro group, a cyano group, an aryl group having 6 to 20 carbon atoms which may be substituted with ^Z3 , or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with ^Z3 ;
^Z2 is a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms which may be substituted with ^Z3 , an alkenyl group having 2 to 20 carbon atoms which may be substituted with ^Z3 , or an alkynyl group having 2 to 20 carbon atoms which may be substituted with ^Z3 ;
^Z3 is a halogen atom, a nitro group, or a cyano group.
2. Aniline derivatives of 1 in which all Ar's are the same group.
3. The aniline derivative according to 2, wherein Ar is a group represented by any one of formulas (Ar1) to (Ar5).
4. The aniline derivative of 3, wherein Ar is a group represented by formula (Ar1).
5. A method for producing the aniline derivative according to 1, comprising reacting paraphenylenediamine with a carbazole derivative represented by the following formula (N1) in the presence of a catalyst:

(In the formula, Ar is the same as defined above, and X is a halogen atom or a pseudohalogen group.)

The aniline derivative of the present invention is easily soluble in an organic solvent, and can be dissolved in an organic solvent alone or together with a dopant to easily prepare a charge transport composition. In addition, the aniline derivative of the present invention provides a thin film with high charge transport properties, and this thin film can be suitably applied to electronic devices such as organic EL devices.

The aniline derivative of the present invention is represented by the following formula (1).

In formula (1), each Ar is independently a group represented by any one of the following formulae (Ar1) to (Ar9).

In formulae (Ar1) to (Ar9), R ¹ to R ²¹ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with Z ¹ , an alkenyl group having 2 to 20 carbon atoms which may be substituted with Z ¹ , an alkynyl group having 2 to 20 carbon atoms which may be substituted with Z ¹ , an aryl group having 6 to 20 carbon atoms which may be substituted with Z ² , or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with Z ^2. Z ¹ is a halogen atom, a nitro group, a cyano group, an aryl group having 6 to 20 carbon atoms which may be substituted with Z ^{3 ,} or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with Z 3. Z ² is a halogen atom, a ^nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms which may be substituted with Z ³ , an alkenyl group having 2 to 20 carbon atoms which may be substituted with Z 3, or an alkynyl group having 2 to 20 carbon atoms which may be substituted with Z ³ . ^Z3 is a halogen atom, a nitro group or a cyano group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., with a fluorine atom being preferred.

The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic. Specific examples include linear or branched alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic alkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl.

The alkenyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples include ethenyl, n-1-propenyl, n-2-propenyl, 1-methylethenyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentenyl, and n-1-decenyl.

The alkynyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include an ethynyl group, an n-1-propynyl group, an n-2-propynyl group, an n-1-butynyl group, an n-2-butynyl group, an n-3-butynyl group, a 1-methyl-2-propynyl group, an n-1-pentynyl group, an n-2-pentynyl group, an n-3-pentynyl group, an n-4-pentynyl group, a 1-methyl-n-butynyl group, a 2-methyl-n-butynyl group, a 3-methyl-n-butynyl group, a 1,1-dimethyl-n-propynyl group, an n-1-hexynyl group, and an n-1-decynyl group.

Specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a tolyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, and a 9-phenanthryl group.

Specific examples of the heteroaryl group having 2 to 20 carbon atoms include oxygen-containing heteroaryl groups such as 2-thienyl group, 3-thienyl group, 2-furanyl group, 3-furanyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 3-isoxazolyl group, 4-isoxazolyl group, and 5-isoxazolyl group, and sulfur-containing heteroaryl groups such as 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isothiazolyl group, 4-isothiazolyl group, and 5-isothiazolyl group. a aryl group, a 2-imidazolyl group, a 4-imidazolyl group, a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group, a 2-pyrazyl group, a 3-pyrazyl group, a 5-pyrazyl group, a 6-pyrazyl group, a 2-pyrimidyl group, a 4-pyrimidyl group, a 5-pyrimidyl group, a 6-pyrimidyl group, a 3-pyridazyl group, a 4-pyridazyl group, a 5-pyridazyl group, a 6-pyridazyl group, a 1,2,3-triazin-4-yl group, a 1,2,3-triazin-5-yl group, a 1,2,4-triazin-3-yl group, -yl group, 1,2,4-triazin-5-yl group, 1,2,4-triazin-6-yl group, 1,3,5-triazin-2-yl group, 1,2,4,5-tetrazin-3-yl group, 1,2,3,4-tetrazin-5-yl group, 2-quinolinyl group, 3-quinolinyl group, 4-quinolinyl group, 5-quinolinyl group, 6-quinolinyl group, 7-quinolinyl group, 8-quinolinyl group, 1-isoquinolinyl group, 3-isoquinolinyl group, 4-isoquinolinyl group, 5-isoquinolinyl and nitrogen-containing heteroaryl groups such as a 6-isoquinolinyl group, a 7-isoquinolinyl group, an 8-isoquinolinyl group, a 2-quinoxanyl group, a 5-quinoxanyl group, a 6-quinoxanyl group, a 2-quinazolinyl group, a 4-quinazolinyl group, a 5-quinazolinyl group, a 6-quinazolinyl group, a 7-quinazolinyl group, an 8-quinazolinyl group, a 3-cinnolinyl group, a 4-cinnolinyl group, a 5-cinnolinyl group, a 6-cinnolinyl group, a 7-cinnolinyl group, and an 8-cinnolinyl group.

Among them, R ¹ to R ²¹ are preferably an aryl group having 6 to 20 carbon atoms which may be substituted with Z ² , or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with Z ² , more preferably an aryl group having 6 to 20 carbon atoms which may be substituted with Z ² , and even more preferably a phenyl group which may be substituted with Z ² , a 1-naphthyl group which may be substituted with Z ² , or a 2-naphthyl group which may be substituted with Z ^2. Z ² is preferably a halogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with Z ³ , or an alkenyl group having 2 to 20 carbon atoms which may be substituted with Z ^3. Z ³ is preferably a halogen atom, and more preferably a fluorine atom.

In the present invention, from the viewpoint of ease of synthesis of the aniline derivative, it is preferable that all of the Ar's are the same group. Furthermore, from the viewpoint of reproducibly obtaining a highly uniform composition when preparing a charge transport composition, a group represented by any one of formulas (Ar1) to (Ar5) is more preferable, and a group represented by formula (Ar1) is optimal.

（式中、Ｐｈは、フェニル基である。） Preferred specific examples of the aniline derivative of the present invention are listed below, but the invention is not limited thereto.

(In the formula, Ph is a phenyl group.)

（式中、Ａｒは、前記と同じであり、Ｘは、ハロゲン原子又は擬ハロゲン基である。） The aniline derivative of the present invention can be produced by reacting paraphenylenediamine (1,4-phenylenediamine) with a halogenated or pseudohalogenated carbazole derivative represented by the following formula (N1) in the presence of a catalyst.

(In the formula, Ar is the same as defined above, and X is a halogen atom or a pseudohalogen group.)

The halogen atom may be the same as those described above, but a chlorine atom, a bromine atom, or an iodine atom is preferred. The pseudohalogen group may be a (fluoro)alkylsulfonyloxy group such as a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group, or a nonafluorobutanesulfonyloxy group; or an aromatic sulfonyloxy group such as a benzenesulfonyloxy group or a toluenesulfonyloxy group.

The charging ratio of 1,4-phenylenediamine to the halogenated or pseudo-halogenated carbazole derivative can be an equivalent or more of the halogenated or pseudo-halogenated carbazole derivative relative to the total amount of NH groups in 1,4-phenylenediamine, but a ratio of about 1 to 1.2 equivalents is preferable.

Examples of the catalyst used in the reaction include copper catalysts such as copper chloride, copper bromide, and copper iodide; and palladium catalysts such as tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ), bis(triphenylphosphine)dichloropalladium (Pd(PPh ₃ ) ₂ Cl ₂ ), bis(dibenzylideneacetone)palladium (Pd(dba) ₂ ), tris(dibenzylideneacetone)dipalladium (Pd ₂ (dba) ₃ ), bis[tri(t-butylphosphine)]palladium (Pd(Pt-Bu ₃ ) ₂ ), and palladium acetate (Pd(OAc) ₂ ). These catalysts may be used alone or in combination of two or more.

These catalysts may also be used together with known suitable ligands. Examples of such ligands include tertiary phosphines such as triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri-t-butylphosphine, di-t-butyl(phenyl)phosphine, di-t-butyl(4-dimethylaminophenyl)phosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, and 1,1'-bis(diphenylphosphino)ferrocene; and tertiary phosphites such as trimethylphosphite, triethylphosphite, and triphenylphosphite.

The amount of catalyst used may be about 0.01 to 0.2 mol per 1 mol of halogenated or pseudohalogenated carbazole derivative, with about 0.15 mol being preferred. When a ligand is used, the amount may be 0.1 to 5 equivalents per mol of catalyst, with 1 to 2 equivalents being preferred.

When all the raw material compounds are solid or from the viewpoint of efficiently obtaining the desired aniline derivative, each of the above reactions is carried out in a solvent. When using a solvent, there are no particular limitations on the type of solvent as long as it does not adversely affect the reaction. Specific examples include aliphatic hydrocarbons (pentane, n-hexane, n-octane, n-decane, decalin, etc.), halogenated aliphatic hydrocarbons (chloroform, dichloromethane, dichloroethane, carbon tetrachloride, etc.), aromatic hydrocarbons (benzene, nitrobenzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, etc.), halogenated aromatic hydrocarbons (chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, etc.), ethers (diethyl ether, diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, dioxane, etc.), and the like. Examples of the solvent include, but are not limited to, hexane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone, cyclohexanone, etc.), amides (N,N-dimethylformamide, N,N-dimethylacetamide, etc.), lactams and lactones (N-methylpyrrolidone, γ-butyrolactone, etc.), ureas (N,N-dimethylimidazolidinone, tetramethylurea, etc.), sulfoxides (dimethyl sulfoxide, sulfolane, etc.), and nitriles (acetonitrile, propionitrile, butyronitrile, etc.). These solvents may be used alone or in combination of two or more.

The reaction temperature may be set appropriately within the range from the melting point to the boiling point of the solvent used, but is usually in the range of about 0 to 200°C, and preferably in the range of 20 to 150°C. After the reaction is completed, post-treatment is carried out according to conventional methods to obtain the desired aniline derivative.

The aniline derivative of the present invention is suitable as a charge transporting material and exhibits excellent solubility in organic solvents. Therefore, a charge transporting composition can be easily prepared by dissolving the aniline derivative of the present invention in an organic solvent.

As such an organic solvent, a highly soluble solvent capable of dissolving the aniline derivative of the present invention can be used. Specific examples of highly soluble solvents include, but are not limited to, organic solvents such as cyclohexanone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutyramide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, and diethylene glycol monomethyl ether. These solvents may be used alone or in combination of two or more. The amount of the solvent used may be 5 to 100% by mass based on the total amount of the solvent used in the composition.

In addition, by including at least one high-viscosity organic solvent having a viscosity of 10 to 200 mPa·s at 25°C, particularly 35 to 150 mPa·s, and a boiling point of 50 to 300°C, particularly 150 to 250°C, at normal pressure (atmospheric pressure), the viscosity of the composition can be easily adjusted, and as a result, a composition that gives a thin film with high flatness and good reproducibility and that is suitable for the coating method used can be prepared. Examples of high-viscosity organic solvents include, but are not limited to, cyclohexanol, ethylene glycol, ethylene glycol diglycidyl ether, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, propylene glycol, and hexylene glycol. These solvents may be used alone or in combination of two or more. The proportion of the high-viscosity organic solvent added to the total solvent used in the composition is preferably within a range in which a solid does not precipitate, and as long as a solid does not precipitate, the proportion is preferably 5 to 80 mass %.

Furthermore, for the purpose of improving the wettability of the substrate, adjusting the surface tension of the solvent, adjusting the polarity, adjusting the boiling point, etc., other solvents can be mixed in a ratio of 1 to 90% by mass, preferably 1 to 50% by mass, based on the total solvent used in the composition. Examples of such solvents include, but are not limited to, propylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether, diacetone alcohol, γ-butyrolactone, ethyl lactate, n-hexyl acetate, etc. These solvents may be used alone or in combination of two or more.

In addition, when the aniline derivative of the present invention has a substituent on at least one nitrogen atom in the molecule, such as an aryl group on the nitrogen atom at position 9 of the carbazole moiety in the molecule, and preferably has substituents on all nitrogen atoms, it becomes easier to prepare a composition using only a low-polarity solvent. Specific examples of such low polarity solvents include, but are not limited to, chlorine-based solvents such as chloroform and chlorobenzene; aromatic hydrocarbon-based solvents such as toluene, xylene, tetralin, cyclohexylbenzene, and decylbenzene; aliphatic alcohol-based solvents such as 1-octanol, 1-nonanol, and 1-decanol; ether-based solvents such as tetrahydrofuran, dioxane, anisole, 4-methoxytoluene, 3-phenoxytoluene, dibenzyl ether, diethylene glycol dimethyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, and triethylene glycol butyl methyl ether; and ester-based solvents such as methyl benzoate, ethyl benzoate, butyl benzoate, dimethyl phthalate, diethyl maleate, isoamyl benzoate, bis(2-ethylhexyl) phthalate, dibutyl maleate, dibutyl oxalate, hexyl acetate, diethylene glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate. These solvents may be used alone or in combination of two or more.

The charge transport composition of the present invention may contain water as a solvent, but from the viewpoint of reproducibly obtaining a highly durable element when the charge transport thin film obtained from the composition is used as a hole injection layer of an organic EL element, the water content is preferably 10% by mass or less of the total solvent, more preferably 5% by mass or less, and it is optimal to use only an organic solvent as the solvent. In this case, "only organic solvent" means that only an organic solvent is used as the solvent, and does not deny the presence of "water" contained in a small amount in the organic solvent or solid content used. In addition, in the present invention, the solid content means components other than the solvent contained in the charge transport composition.

The charge transport composition of the present invention may contain other charge transport substances in addition to the charge transport substance consisting of the aniline derivative of the present invention.

The charge transport composition contains a charge transport substance consisting of the aniline derivative of the present invention and an organic solvent, but depending on the application of the resulting thin film, it may also contain a dopant (charge accepting substance) for the purpose of improving its charge transport ability, etc.

There are no particular limitations on the dopant, so long as it dissolves in at least one solvent used in the composition, and both inorganic and organic dopants can be used. In addition, inorganic and organic dopants may be used alone or in combination of two or more.

The amount of dopant in the composition cannot be generally specified because it varies depending on the desired degree of charge transportability and the type of dopant, but is usually in the range of 0.0001 to 100 parts by mass per 1 part of the aniline derivative represented by formula (1).

In the present invention, an example of a preferred dopant is an ionic compound. Specific examples thereof include an anion represented by the following formula (2a), an anion represented by the following formula (2b), hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, cyanide ion, nitrate ion, nitrite ion, sulfate ion, sulfite ion, perchlorate ion, perbromate ion, periodate ion, chlorate ion, chlorite ion, hypochlorite ion, phosphate ion, phosphite ion, hypophosphite ion, borate ion, isocyanate ion, hydrosulfide ion, tetrafluoroborate ion, hexafluorophosphate ion, hexachloroantimonate ion; carboxylate ions such as acetate ion, trifluoroacetate ion, and benzoate ion; sulfonate ions such as methanesulfonic acid and trifluoromethanesulfonate ion; alkoxide ions such as methoxide ion and t-butoxide ion, and salts thereof composed of counter cations.

In formula (2a), E ¹ is an element belonging to Group 13 or 15 of the long form periodic table. Among these, boron, gallium, phosphorus, and antimony are preferred, and boron is more preferred.

In formula (2a), Ar ¹ to Ar ⁴ are each independently an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. Examples of the aromatic hydrocarbon group and aromatic heterocyclic group include monovalent groups derived from a 5- or 6-membered single ring or 2- to 4-condensed rings. Among these, from the viewpoints of the stability and heat resistance of the compound, monovalent groups derived from benzene, naphthalene, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, etc. are preferred.

Furthermore, it is more preferable that at least one of the groups Ar ¹ to Ar ⁴ has one or more fluorine or chlorine atoms as a substituent. In particular, it is even more preferable that Ar ¹ to Ar ⁴ are perfluoroaryl groups or perfluoroheteroaryl groups in which all of the hydrogen atoms are substituted with fluorine atoms, and it is most preferable that Ar ¹ to Ar ⁴ are perfluoroaryl groups in which all of the hydrogen atoms are substituted with fluorine atoms. Specific examples of perfluoroaryl groups include pentafluorophenyl groups, heptafluoro-2-naphthyl groups, and tetrafluoro-4-pyridyl groups.

In formula (2b), ^E2 is an element belonging to Group 15 of the long periodic table. Among these, phosphorus atom, arsenic atom, and antimony atom are preferred, and phosphorus atom is preferred from the viewpoint of compound stability, ease of synthesis and purification, and toxicity. ^Xa is a halogen atom such as fluorine atom, chlorine atom, and bromine atom, and is preferably fluorine atom or chlorine atom from the viewpoint of compound stability, ease of synthesis and purification, and is most preferably fluorine atom.

The counter cation is preferably a metal ion or an onium ion. The metal ion is preferably a monovalent metal ion, such as Li ⁺ , Na ⁺ , K ⁺ , or Ag ⁺ , with Ag ⁺ being particularly preferred. The onium ion is preferably an iodonium ion, a sulfonium ion, an ammonium ion, or a phosphonium ion.

The onium ion is preferably an iodonium ion represented by the following formula (2c).

In formula (2c), R ¹⁰¹ and R ¹⁰² are each independently an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, and some or all of the hydrogen atoms of these groups may be substituted with a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms.

As the onium ion, an ion represented by the following formula (2d) can also be used.

In formula (2d), E ³ is an element in the third period or later (third to sixth periods) of the periodic table, and an element belonging to group 16 of the long-form periodic table. Among these, in the present invention, from the viewpoints of electron-accepting ability and easy availability, an element in the fifth period or earlier (third to fifth periods) of the periodic table is preferred. That is, E ³ is preferably a sulfur atom, a selenium atom, or a tellurium atom, and more preferably a sulfur atom.

In formula (2d), R ¹⁰³ is an organic group bonded to E ³ via a carbon atom, and R ¹⁰⁴ and R ¹⁰⁵ are each independently any substituent. Two or more adjacent groups among R ¹⁰³ to R ¹⁰⁵ may be bonded to each other to form a ring.

R ¹⁰³ is not particularly limited as long as it is an organic group having a carbon atom at the bonding portion with E ³ , as long as it does not go against the spirit of the present invention. The molecular weight of R ¹⁰³ is usually 1,000 or less, preferably 500 or less. Preferred examples of R ¹⁰³ include alkyl groups, alkenyl groups, alkynyl groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups, from the viewpoint of delocalizing the positive charge. Among them, aromatic hydrocarbons or aromatic heterocyclic groups are preferred, since they delocalize the positive charge and are thermally stable.

The aromatic hydrocarbon group is a monovalent group derived from a 5- or 6-membered monocyclic ring or 2- to 5-condensed rings, and can delocalize a positive charge on the group. Specific examples include monovalent groups derived from benzene, naphthalene, anthracene, phenanthrene, perylene, tetracene, pyrene, benzpyrene, chrysene, triphenylene, acenaphthene, fluorene, and the like. More specific examples include a phenyl group, a tolyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, and a 9-phenanthryl group. Of these, a phenyl group and a tolyl group are preferred, and a tolyl group is more preferred.

The aromatic heterocyclic group is a monovalent group derived from a 5- or 6-membered single ring or 2- to 4-condensed rings, and can delocalize a positive charge on the group. Specific examples include monovalent groups derived from furan, benzofuran, thiophene, benzothiophene, pyrrole, pyrazole, triazole, imidazole, oxadiazole, indole, carbazole, pyrroloimidazole, pyrrolopyrazole, pyrrolopyrrole, thienopyrrole, thienothiophene, furopyrrole, furofuran, thienofuran, benzoisoxazole, benzoisothiazole, benzimidazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, cinnoline, quinoxaline, phenanthridine, benzimidazole, pyrimidine, quinazoline, quinazolinone, azulene, etc.

The alkyl group may be linear, branched, or cyclic, and typically has 1 or more carbon atoms and typically has 12 or less, preferably 6 or less. Specific examples include methyl, ethyl, n-propyl, 2-propyl, n-butyl, isobutyl, t-butyl, and cyclohexyl groups.

The alkenyl group generally has 2 or more carbon atoms and generally has 12 or less carbon atoms, preferably 6 or less carbon atoms. Specific examples include a vinyl group, an allyl group, and a 1-butenyl group.

The alkynyl group generally has 2 or more carbon atoms and generally has 12 or less carbon atoms, preferably 6 or less carbon atoms. Specific examples include an ethynyl group and a propargyl group.

R ¹⁰⁴ and R ¹⁰⁵ are not particularly limited as long as they are not contrary to the gist of the present invention. The molecular weight of R ¹⁰⁴ and R ¹⁰⁵ is usually in the range of 1,000 or less, preferably 500 or less. Examples of R ¹⁰⁴ and R ¹⁰⁵ include an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, an organoamino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylcarbonyloxy group, an alkylthio group, an arylthio group, an alkylsulfonyl group, an arylsulfonyl group, an alkylsulfonyloxy group, an arylsulfonyloxy group, a cyano group, a hydroxy group, a thiol group, and an organosilyl group. Among them, an organic group having a carbon atom at the bond portion with E ³ is preferred from the viewpoint of high electron accepting property like R ¹⁰³ , and for example, an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, and an aromatic heterocyclic group are preferred. In particular, aromatic hydrocarbon groups and aromatic heterocyclic groups are preferred because they have high electron-accepting properties and are thermally stable.

Examples of the alkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group and aromatic heterocyclic group include the same groups as those described in the description of R ¹⁰³ .

The organoamino group includes an amino group substituted with an organic group such as an alkyl group, an aryl group, a heteroaryl group, an aralkyl group, or an acyl group. The amino group substituted with an alkyl group includes an amino group having one or more alkyl groups, usually having one or more carbon atoms and usually having 12 or less, preferably 6 or less. Specific examples thereof include a methylamino group, a dimethylamino group, and a diethylamino group.

The amino group substituted with the aryl group or heteroaryl group includes an amino group having one or more aromatic hydrocarbon groups or aromatic heterocyclic groups, each of which usually has 3 or more carbon atoms, preferably 4 or more carbon atoms, and usually has 25 or less carbon atoms, preferably 15 or less carbon atoms. Specific examples of such groups include a phenylamino group, a diphenylamino group, a tolylamino group, a pyridylamino group, and a thienylamino group.

The amino group substituted with the aralkyl group includes an amino group having one or more aralkyl groups having a carbon number of usually 7 or more and usually 25 or less, preferably 15 or less. Specific examples thereof include a benzylamino group and a dibenzylamino group.

The amino group substituted with the acyl group includes an acylamino group having one or more acyl groups, which usually has 2 or more carbon atoms and usually has 25 or less, preferably 15 or less. Specific examples thereof include an acetylamino group and a benzoylamino group.

The alkoxy group generally has 1 or more carbon atoms and generally has 12 or less carbon atoms, preferably 6 or less carbon atoms. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, and a butoxy group.

The aryloxy group includes an aryloxy group having an aromatic hydrocarbon group or an aromatic heterocyclic group having a carbon number of usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less. Specific examples thereof include a phenyloxy group, a naphthyloxy group, a pyridyloxy group, and a thienyloxy group.

The acyl group generally has 1 or more carbon atoms and generally has 25 or less carbon atoms, preferably 15 or less carbon atoms. Specific examples include a formyl group, an acetyl group, and a benzoyl group.

The alkoxycarbonyl group has a carbon number of typically 2 or more and typically 10 or less, preferably 7 or less. Specific examples include a methoxycarbonyl group and an ethoxycarbonyl group.

The aryloxycarbonyl group includes an aromatic hydrocarbon group or an aromatic heterocyclic group having a carbon number of usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less. Specific examples thereof include a phenoxycarbonyl group and a pyridyloxycarbonyl group.

The alkylcarbonyloxy group has a carbon number of typically 2 or more and typically 10 or less, preferably 7 or less. Specific examples thereof include an acetoxy group and a trifluoroacetoxy group.

The alkylthio group has a carbon number of typically 1 or more and typically 12 or less, preferably 6 or less. Specific examples include a methylthio group and an ethylthio group.

The arylthio group has a carbon number of typically 3 or more, preferably 4 or more, and typically 25 or less, preferably 14 or less. Specific examples include a phenylthio group, a naphthylthio group, and a pyridylthio group.

Specific examples of the alkylsulfonyl group and arylsulfonyl group include a mesyl group and a tosyl group.

Specific examples of the alkylsulfonyloxy group and arylsulfonyloxy group include a mesyloxy group and a tosyloxy group.

Specific examples of the organosilyl group include a trimethylsilyl group and a triphenylsilyl group.

The groups exemplified as R ¹⁰³ , R ¹⁰⁴ and R ¹⁰⁵ above may be further substituted with other substituents as long as it does not go against the spirit of the present invention. The type of the substituent is not particularly limited, and examples thereof include halogen atoms, cyano groups, thiocyano groups, nitro groups, etc., in addition to the groups exemplified as R ¹⁰³ , R ¹⁰⁴ and R ^105. Among them, from the viewpoint of not interfering with the heat resistance and electron accepting property of the ionic compound (electron accepting ionic compound), an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group is preferred.

Among the above, the ionic compounds represented by the following formulas (2-1) to (2-4) (see Japanese Patent No. 5381931) can be preferably used.

Furthermore, onium borate salts (which are electrically neutral salts) consisting of a monovalent or divalent anion represented by formula (3a) and a counter cation represented by any one of formulas (4a) to (4e) can also be suitably used.

In formula (3a), Ar ¹¹ to Ar ¹⁶ are each independently an aryl group which may have a substituent or a heteroaryl group which may have a substituent, and L is an alkylene group, -NH-, an oxygen atom, a sulfur atom or -CN ⁺ -.

The aryl group includes aryl groups having 6 to 20 carbon atoms. Specific examples thereof are the same as those exemplified in the description of R ¹ to R ²¹ , with phenyl, tolyl, and naphthyl being preferred. The heteroaryl group includes heteroaryl groups having 2 to 20 carbon atoms. Specific examples thereof are the same as those exemplified in the description of R ¹ to R ²¹ .

Examples of the substituents include halogen atoms, nitro groups, cyano groups, alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, and alkynyl groups having 2 to 20 carbon atoms.

Specific examples of the alkyl group include the same as those exemplified in the description of R ¹ to R ²¹ , with alkyl groups having 1 to 18 carbon atoms being preferred, and alkyl groups having 1 to 8 carbon atoms being more preferred. Specific examples of the halogen atoms, alkenyl groups and alkynyl groups include the same as those exemplified in the description of R ¹ to R ²¹ .

The aryl group and heteroaryl group preferably have one or more electron-withdrawing groups as a substituent. Among the aforementioned substituents, examples of the electron-withdrawing groups include halogen atoms, nitro groups, and cyano groups, with halogen atoms being preferred and fluorine atoms being particularly preferred.

In formula (3a), L is an alkylene group, --NH--, an oxygen atom, a sulfur atom or --CN.sup. ⁺ --, with --CN.sup. ⁺ -- being preferred.

The alkylene group may be linear, branched, or cyclic, and includes alkylene groups having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. Specific examples include methylene, methylmethylene, dimethylmethylene, ethylene, trimethylene, propylene, tetramethylene, pentamethylene, and hexamethylene groups.

An anion represented by formula (3a) that can be suitably used in the present invention includes, but is not limited to, an anion represented by formula (3b).

In the present invention, the onium borate salt may be used alone or in combination of two or more. If necessary, other known onium borate salts may be used in combination. The onium borate salt may be synthesized by referring to known methods described in, for example, JP-A-2005-314682.

The onium borate salt may be dissolved in an organic solvent in advance when preparing the charge transport composition in order to facilitate dissolution in the composition. Examples of such organic solvents include carbonates such as propylene carbonate, ethylene carbonate, 1,2-butylene carbonate, dimethyl carbonate, and diethyl carbonate; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; polyhydric alcohols and derivatives thereof such as ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol, and monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, and monophenyl ether of dipropylene glycol monoacetate; dioxanes, diisopropyl ether ... Examples of the solvent include cyclic ethers such as ethyl formate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl pyruvate, ethyl ethoxyacetate, methyl methoxypropionate, ethyl ethoxypropionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, and 3-methyl-3-methoxybutyl acetate; and aromatic hydrocarbons such as toluene, xylene, 3-phenoxytoluene, 4-methoxytoluene, methyl benzoate, cyclohexylbenzene, tetralin, and isophorone. These solvents may be used alone or in combination of two or more. The amount of the solvent used is preferably 15 to 1,000 parts by mass, and more preferably 30 to 500 parts by mass, based on 100 parts by mass of the onium borate salt.

When the charge transport composition contains the onium borate salt as a dopant, the content is preferably such that the mass ratio of charge transport substance (aniline derivative of the present invention) to onium borate salt is approximately 1:0.01 to 20, more preferably approximately 1:0.01 to 10, even more preferably approximately 1:0.01 to 2, and even more preferably approximately 1:0.1 to 2.

In the charge transport composition, it is preferable that the charge transport material and the dopant are completely dissolved or uniformly dispersed in the solvent, and it is optimal that they are completely dissolved.

The charge transport composition may contain an organic silane compound or a nonionic fluorine-containing surfactant for the purpose of improving the injection into the hole transport layer when the resulting thin film is used as a hole injection layer of an organic EL element, and improving the life characteristics of the element, etc., and the content thereof is usually about 1 to 30 parts by mass per 100 parts by mass of the total of the charge transport substance and dopant.

The solids concentration in the charge transport composition is typically about 0.1 to 20% by mass, preferably 0.5 to 15% by mass, from the viewpoint of suppressing precipitation of the charge transport material while ensuring a sufficient film thickness.

The viscosity of the charge transport composition is typically 1 to 50 mPa·s at 25° C., and the surface tension is typically 20 to 50 mN/m at 25° C. The viscosity and surface tension of the charge transport composition can be adjusted by changing the types of organic solvents used, their ratios, solids concentration, etc., taking into consideration various factors such as the coating method used and the desired film thickness.

The charge transport composition can be produced by dissolving the aniline derivative of the present invention in an organic solvent. The aniline derivative of the present invention may be dissolved in an organic solvent in advance, and other organic solvents may be added thereto in sequence, or a mixed solvent of all the solvents to be used may be prepared in advance, and the aniline derivative of the present invention may be dissolved therein. If necessary, the composition may be heated to promote dissolution of the aniline derivative of the present invention, while taking care not to decompose or deteriorate the components contained in the composition. The same method is also followed when the charge transport composition contains components other than the aniline derivative of the present invention and the solvent. Furthermore, the charge transport composition may be filtered using a submicrometer-order filter after dissolving the charge transport material in an organic solvent, from the viewpoint of reproducibly obtaining a thin film with a higher flatness.

By applying the charge transport composition described above onto a substrate and baking it, a charge transport thin film can be formed on the substrate.

The method for applying the composition is not particularly limited, and examples thereof include a dip method, a spin coating method, a transfer printing method, a roll coating method, an inkjet method, a spray method, a slit coating method, etc. It is preferable to adjust the viscosity and surface tension of the composition depending on the application method.

The firing atmosphere is not particularly limited, and thin films with uniform film surface and charge transport properties can be obtained not only in an atmospheric atmosphere (air) but also in an inert gas such as nitrogen or in a vacuum, but firing is usually performed in an atmospheric atmosphere.

The baking conditions are not particularly limited, but for example, the material is heated and baked using a hot plate. Usually, the baking temperature is set within the range of 100 to 260°C, and the baking time is set within the range of 1 minute to 1 hour, taking into consideration the desired charge transport properties, etc. Furthermore, multi-stage baking at two or more different temperatures may be performed as necessary.

There are no particular limitations on the thickness of the charge-transporting thin film, but when used as a functional layer in an organic EL element, a thickness of 5 to 300 nm is preferred. Methods for changing the film thickness include, for example, changing the solids concentration in the charge-transporting composition or changing the amount of liquid during application.

The charge transporting thin film can be suitably used as a functional layer of an organic EL element. When the charge transporting thin film is applied to an organic EL element, the organic EL element has a pair of electrodes and has the charge transporting thin film between the electrodes.

Representative configurations of the organic EL element include, but are not limited to, the following (a) to (f). In the following configurations, an electron blocking layer or the like can be provided between the light-emitting layer and the anode, and a hole (positive hole) blocking layer or the like can be provided between the light-emitting layer and the cathode, if necessary. In addition, the hole injection layer, the hole transport layer, or the hole injection transport layer may also function as an electron blocking layer, etc., and the electron injection layer, the electron transport layer, or the electron injection transport layer may also function as a hole (positive hole) blocking layer, etc. Furthermore, an arbitrary functional layer can be provided between each layer, if necessary.
(a) anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode (b) anode/hole injection layer/hole transport layer/light emitting layer/electron injection transport layer/cathode (c) anode/hole injection transport layer/light emitting layer/electron transport layer/electron injection layer/cathode (d) anode/hole injection transport layer/light emitting layer/electron injection transport layer/cathode (e) anode/hole injection layer/hole transport layer/light emitting layer/cathode (f) anode/hole injection transport layer/light emitting layer/cathode

The terms "hole injection layer", "hole transport layer" and "hole injection transport layer" refer to layers formed between the light-emitting layer and the anode, which have the function of transporting holes from the anode to the light-emitting layer. When only one layer of a hole-transporting material is provided between the light-emitting layer and the anode, it is the "hole injection transport layer", and when two or more layers of a hole-transporting material are provided between the light-emitting layer and the anode, the layer closest to the anode is the "hole injection layer" and the other layers are "hole transport layers". In particular, the hole injection (transport) layer is a thin film that is excellent not only in terms of hole acceptance from the anode, but also in terms of hole injection into the hole transport (light-emitting) layer.

An "electron injection layer," "electron transport layer," and "electron injection transport layer" are layers formed between the light-emitting layer and the cathode and have the function of transporting electrons from the cathode to the light-emitting layer. When only one layer of an electron-transporting material is provided between the light-emitting layer and the cathode, it is the "electron injection transport layer," and when two or more layers of an electron-transporting material are provided between the light-emitting layer and the cathode, the layer closest to the cathode is the "electron injection layer," and the other layers are "electron transport layers."

An "emissive layer" is an organic layer that has the ability to emit light, and contains a host material and a dopant material when a doping system is used. In this case, the host material primarily functions to promote the recombination of electrons and holes and confine excitons within the emissive layer, while the dopant material primarily functions to efficiently emit light from the excitons obtained by recombination. In the case of phosphorescent elements, the host material primarily functions to confine excitons generated by the dopant within the emissive layer.

The charge transport thin film is suitable as a functional layer provided between an anode and an emitting layer in an organic EL element, and is more suitable as a hole injection layer, a hole transport layer, or a hole injection transport layer, and is even more suitable as a hole injection layer.

When preparing an organic EL element using the charge transport composition, the materials and preparation methods used include, but are not limited to, those listed below.

An example of a method for producing an OLED element having a hole transport layer made of a thin film obtained from the charge transport composition is as follows. Note that it is preferable to previously perform a surface treatment on the electrodes, such as cleaning with alcohol, pure water, etc., or UV ozone treatment, oxygen plasma treatment, etc., to the extent that it does not adversely affect the electrodes.

A hole injection layer made of the charge transport thin film is formed on an anode substrate by the above-mentioned method. This is introduced into a vacuum deposition apparatus, and a hole transport layer, a light emitting layer, an electron transport layer, an electron transport layer/hole blocking layer, and a cathode metal are sequentially deposited. Alternatively, instead of forming the hole transport layer and the light emitting layer by deposition in this method, these layers are formed by a wet process using a hole transport layer forming composition containing a hole transport polymer and a light emitting layer forming composition containing a light emitting polymer. If necessary, an electron blocking layer may be provided between the light emitting layer and the hole transport layer.

Anode materials include transparent electrodes such as indium tin oxide (ITO) and indium zinc oxide (IZO), metal anodes made of metals such as aluminum or alloys thereof, and preferably those that have been subjected to planarization treatment. Polythiophene derivatives and polyaniline derivatives with high charge transport properties can also be used. Other metals that make up the metal anode include, but are not limited to, gold, silver, copper, indium, and alloys thereof.

Examples of materials for forming the light-emitting layer include, but are not limited to, low molecular weight light-emitting materials such as metal complexes of 8-hydroxyquinoline, such as tris(8-quinolinolato)aluminum(III) ( _Alq3 ) and bis(8-quinolinolato)zinc(II), aluminum complexes, zinc complexes, and the like, metal complexes of 10-hydroxybenzo[h]quinoline, bisstyrylbenzene derivatives, bisstyrylarylene derivatives, metal complexes of (2-hydroxyphenyl)benzothiazole, and silole derivatives; and systems in which a light-emitting material and an electron transfer material are mixed into a polymer compound, such as poly(p-phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly(3-alkylthiophene), or polyvinylcarbazole. In addition, when forming a light-emitting layer by vapor deposition, it may be co-deposited with a light-emitting dopant. Examples of the light-emitting dopant include, but are not limited to, metal complexes such as tris(2-phenylpyridine)iridium(III) (Ir(PPy) ₃ ), naphthacene derivatives such as rubrene, quinacridone derivatives, and condensed polycyclic aromatic rings such as perylene.

Materials for forming the electron transport layer/hole blocking layer include, but are not limited to, oxydiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, pyrimidine derivatives, etc.

Materials for forming the electron injection layer include, but are not limited to, metal oxides such as lithium oxide ( _Li2O ), magnesium oxide ( _MgO ), and alumina ( _Al2O3 ), and metal fluorides such as lithium fluoride (LiF) and sodium fluoride (NaF).

Cathode materials include, but are not limited to, aluminum, magnesium-silver alloy, aluminum-lithium alloy, etc.

Materials for forming the electron blocking layer include, but are not limited to, tris(phenylpyrazole)iridium.

Examples of hole transport polymers include poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,1'-biphenylene-4,4-diamine)], poly[(9,9-bis{1'-penten-5'-yl}fluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine]-end-capped With polysilsesquioxane, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], and the like.

Examples of luminescent polymers include polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), polyphenylenevinylene derivatives such as poly(2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylenevinylene) (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and polyvinylcarbazole (PVCz).

The materials constituting the anode, cathode, and layers formed between them differ depending on whether an element having a bottom emission structure or a top emission structure is being manufactured, so the materials are selected appropriately, taking this into consideration.

Typically, in elements with a bottom emission structure, a transparent anode is used on the substrate side and light is extracted from the substrate side, whereas in elements with a top emission structure, a reflective anode made of metal is used and light is extracted from the transparent electrode (cathode) side opposite the substrate. Therefore, in terms of anode materials, when manufacturing elements with a bottom emission structure, a transparent anode such as ITO is used, and when manufacturing elements with a top emission structure, a reflective anode such as Al/Nd is used.

In order to prevent deterioration of the characteristics of the organic EL element of the present invention, it may be sealed, if necessary, with a moisture scavenger, etc., in accordance with standard procedures.

The aniline derivative of the present invention has sublimation properties and can be used to easily form a vapor deposition film. Therefore, depending on the application, a charge transporting thin film obtained by a vapor deposition method using the aniline derivative of the present invention may be used instead of a charge transporting thin film obtained from the charge transporting composition.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. The apparatus used is as follows.
(1) LDI-MS: Bruker AutoFlex
(2) ^1H -NMR: JNM-ECP300 FT NMR SYSTEM manufactured by JEOL Ltd.
(3) Substrate cleaning: Substrate cleaning equipment manufactured by Choshu Sangyo Co., Ltd. (low pressure plasma method)
(4) Coating of composition: Spin coater MS-A100 manufactured by Mikasa Co., Ltd.
(5) Film thickness measurement: Kosaka Laboratory Co., Ltd. micro shape measuring instrument Surfcorder ET-4000
(6) Fabrication of element: Multi-function deposition system C-E2L1G1-N manufactured by Choshu Sangyo Co., Ltd.
(7) Measurement of current density of element: Multi-channel IVL measurement device manufactured by EHC Corporation

[1] Preparation of compound [Example 1]

In a flask, 0.502 g of 1,4-phenylenediamine, 6.26 g of 2-bromo-9-phenyl-9H-carbazole, 0.106 g of bis(dibenzylideneacetone)palladium, and 2.24 g of sodium t-butoxide were placed, and the atmosphere in the flask was replaced with nitrogen. 10 mL of toluene and 1.3 mL of a toluene solution of phenyldi-t-butylphosphine (concentration: 62.5 g/L) that had been prepared separately were added, and the mixture was stirred at 90°C for 3 hours. After the reaction mixture was cooled to room temperature, toluene and saturated saline were placed in a separatory funnel together with the cooled reaction mixture, and the organic layer was collected. Activated carbon was added to the collected organic layer, and the mixture was stirred at room temperature for 0.5 hours, followed by silica gel filtration, and the obtained filtrate was concentrated.
The obtained concentrated solution was added dropwise to a mixed solvent of methanol and ethyl acetate and stirred for a while. The obtained slurry solution was filtered, and the obtained filter cake was dried to obtain 2.96 g (yield: 59%) of the desired aniline derivative A. The obtained target product was identified by ¹ H-NMR.
^1H -NMR(500MHz, DMSO-d6) δ[ppm]: 8.09-8.15(m, 8H), 7.54-7.57(m, 8H), 7.43-7.47(m, 12H), 7.33-7.37(m, 4H), 7.24-7.30(m, 8H), 7.05(m, 8H), 6.92-6.94(m, 4H).

[Synthesis Example 1] Preparation of onium borate salt (1) Synthesis of intermediate

A flask was charged with 6,068 mL of diethyl ether, 151.7 g of tris(pentafluorophenyl)borane, and 9.4 g of potassium cyanide, and the mixture was stirred at 34 to 36° C. for 3 hours. The reaction mixture was then concentrated at normal pressure to obtain 267.2 g of a brown liquid. The obtained brown liquid was concentrated under reduced pressure at 55° C. The obtained solid was dried under reduced pressure at 35° C. for 16 hours to obtain 157.7 g of an intermediate represented by formula (Q-1). The obtained target product was identified by LDI-MS.
LDI-MS m/Z found: 1050.12 ([M] ^- calcd: 1049.97).

(2) Synthesis of onium borate salt P

Into a flask, 11.043 g of diphenyl[4-(phenylthio)phenyl]sulfonium trifluoromethanesulfonate, 22.000 g of the intermediate represented by formula (Q-1), 110 mL of ion-exchanged water, and 110 mL of diethyl ether were placed and stirred at 25° C. for 16 hours. Thereafter, the reaction mixture was placed in a separatory funnel, and the aqueous layer was removed while leaving the organic layer. The remaining organic layer was washed with ion-exchanged water (100 mL x 5 times) and then recovered. The organic solvent was distilled off from the recovered organic layer under reduced pressure at 40 to 45° C., and the resulting residue was dried under reduced pressure for 20 hours to obtain 24 g of onium borate salt P. The obtained target product was identified by ¹ H-NMR and LDI-MS.
^1H -NMR (300MHz, DMSO-D6): δ 7.40-7.80 (19H, m)
LDI-MS m/Z found: 371.04 ([M] ⁺ calcd: 371.09).
LDI-MS m/Z found: 1050.11 ([M] ^- calcd: 1049.97).

[2] Preparation of charge transport composition [Reference Example 1]
To a mixture of 113 mg of aniline derivative A and 150 mg of onium borate salt P, 5.0 g of xylene was added and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered through a syringe filter having a pore size of 0.2 μm to obtain a charge transporting composition.

[3] Preparation of organic EL element and evaluation of its characteristics [Reference Example 2]
The charge transport composition obtained in Reference Example 1 was applied to an ITO substrate using a spin coater, and then dried at 120°C for 1 minute in an air atmosphere. The dried ITO substrate was then inserted into a glove box and baked at 150°C for 10 minutes in an air atmosphere to form a 50 nm thin film on the ITO substrate. As the ITO substrate, a 25 mm x 25 mm x 0.7 t glass substrate with indium tin oxide (ITO) patterned on the surface to a thickness of 150 nm was used, and impurities on the surface were removed using an _O2 plasma cleaning device (150 W, 30 seconds) before use.
Next, a 120 nm film of α-NPD (N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine) was formed at 0.2 nm/sec on the ITO substrate on which the thin film was formed using ^a deposition apparatus (vacuum degree 1.0×10 -5 Pa). Next, a 10 nm film of an electron blocking material HTEB-01 manufactured by Kanto Chemical Co., Ltd. was formed. Next, an emitting layer host material NS60 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. and an emitting layer dopant material Ir(PPy) ₃ were co-deposited. The deposition rate of the co-deposition was controlled so that the concentration of Ir(PPy) ₃ was 6%, and a 40 nm film was laminated. Next, thin films of Alq ₃ , lithium fluoride, and aluminum were sequentially laminated to obtain an organic EL device. In this case, the deposition rates were 0.2 nm/sec for _Alq3 and aluminum, and 0.02 nm/sec for lithium fluoride, and the film thicknesses were 20 nm, 0.5 nm, and 80 nm, respectively.
In order to prevent deterioration of characteristics due to the influence of oxygen, water, etc. in the air, the organic EL element was sealed with a sealing substrate, and then its characteristics were evaluated. Sealing was performed according to the following procedure. In a nitrogen atmosphere with an oxygen concentration of 2 ppm or less and a dew point of -76°C or less, the organic EL element was placed between the sealing substrates, and the sealing substrates were bonded together with an adhesive (Moresco Moisture Cut Wb90US(P) manufactured by MORESCO Corporation). At this time, a moisture scavenger (HD-071010W-40 manufactured by DYNIC Co., Ltd.) was placed in the sealing substrate together with the organic EL element. The bonded sealing substrates were irradiated with UV light (wavelength: 365 nm, irradiation amount: 6,000 mJ/cm ² ), and then annealed at 80°C for 1 hour to harden the adhesive.

The resulting device was driven at 5,000 cd/ ^m2 and the driving voltage, current density, current efficiency, luminous efficiency and external luminescence quantum yield (EQE) were measured. The results are shown in Table 1.

As shown in Table 1, it was found that organic EL elements using the aniline derivatives of the present invention operated satisfactorily.

Claims (5)

An aniline derivative represented by the following formula (1):

[In the formula, each Ar is a group represented by the following formula (Ar1 ) :

(In the formula, R ¹ is an alkyl group having 1 to 20 carbon atoms which may be substituted with Z ¹ , an alkenyl group having 2 to 20 carbon atoms which may be substituted with Z ¹ , an alkynyl group having 2 to 20 carbon atoms which may be substituted with Z ¹ , an aryl group having 6 to 20 carbon atoms which may be substituted with Z ² , or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with Z ² ;
^Z1 is a halogen atom, a nitro group, a cyano group, an aryl group having 6 to 20 carbon atoms which may be substituted with ^Z3 , or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with ^Z3 ;
^Z2 is a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms which may be substituted with ^Z3 , an alkenyl group having 2 to 20 carbon atoms which may be substituted with ^Z3 , or an alkynyl group having 2 to 20 carbon atoms which may be substituted with ^Z3 ;
^Z3 is a halogen atom, a nitro group, or a cyano group. R ¹ But, Z ² an aryl group having 6 to 20 carbon atoms which may be substituted with ² 2. The aniline derivative according to claim 1, wherein the heteroaryl group has 2 to 20 carbon atoms and may be substituted with R ¹ But, Z ² 3. The aniline derivative according to claim 2, wherein the aryl group has 6 to 20 carbon atoms and may be substituted with R ¹ But, Z ² a phenyl group optionally substituted with ² 1-naphthyl group optionally substituted by Z ² 4. The aniline derivative according to claim 3, wherein the 2-naphthyl group is optionally substituted with 2. The method for producing an aniline derivative according to claim 1, which comprises reacting paraphenylenediamine with a carbazole derivative represented by the following formula (N1) in the presence of a catalyst:

(In the formula, Ar is the same as defined above, and X is a halogen atom or a pseudohalogen group.)