WO2020203594A1

WO2020203594A1 - Fluorene derivative and use thereof

Info

Publication number: WO2020203594A1
Application number: PCT/JP2020/013505
Authority: WO
Inventors: 博史太田; 歳幸遠藤
Original assignee: 日産化学株式会社
Priority date: 2019-03-29
Filing date: 2020-03-26
Publication date: 2020-10-08
Also published as: JPWO2020203594A1; KR20210144750A; CN113631536A; TW202104169A

Abstract

Provided is a fluorene derivative represented by formula (1). (In the formula, Z¹ and Z² are predetermined divalent groups, and Ar¹ and Ar² are each independently a C6-20 aryl group or a C2-20 heteroaryl group, and may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a C1-20 alkyl group, a C3-20 cycloalkyl group, a C4-20 bicycloalkyl group, a C2-20 alkenyl group, a C2-20 alkynyl group, or a C1-20 alkoxy group. Ar³ and Ar⁴ are each independently a predetermined aromatic-ring-containing group.)

Description

Fluorene derivatives and their use

The present invention relates to a fluorene derivative and its use.

In the organic electroluminescence (EL) device, a charge transporting thin film made of an organic compound is used as a light emitting layer and a charge injection layer. In particular, the hole injection layer is responsible for the transfer of electric charges between the anode and the hole transport layer or the light emitting layer, and fulfills an important function for achieving low voltage drive and high brightness of the organic EL element.

Until now, various incorporations have been made to improve the performance of organic EL elements, but efforts are being made to adjust the refractive index of the functional film used for the purpose of improving the light extraction efficiency. Specifically, the high efficiency of the device is achieved by using a hole injection layer or a hole transport layer having a relatively high or low refractive index in consideration of the overall configuration of the device and the refractive index of other adjacent members. Attempts have been made to achieve this (Patent Documents 1 and 2). As described above, the refractive index is an important factor in the design of the organic EL element, and in the material for the organic EL element, the refractive index is also considered to be an important physical property value to be considered.

Further, in recent years, the charge-transporting thin film for organic EL elements has been in the visible region because the coloring of the charge-transporting thin film used for the organic EL element reduces the color purity and color reproducibility of the organic EL element. It is desired to have high transparency and high transparency (see Patent Document 3).

The method of forming the hole injection layer is roughly divided into a dry process represented by a vapor deposition method and a wet process represented by a spin coating method. Comparing each of these processes, the wet process can efficiently produce a thin film having a large area and high flatness. Therefore, as the area of organic EL displays is increasing, there is always a demand for a wet process material that can be formed by a wet process and provides a charge-transporting thin film having excellent refractive index and transparency. ..

Special Table 2007-536718 Special Table 2017-501585 International Publication No. 2013/0426223

The present invention has been made in view of the above circumstances, and when a thin film having good charge transportability, high refractive index and high transparency is provided by low-temperature firing, and this thin film is applied to a hole injection layer or the like. It is an object of the present invention to provide a compound capable of realizing an organic EL device having excellent characteristics.

As a result of diligent studies to achieve the above object, the present inventors have obtained a thin film obtained by using a predetermined fluorene derivative, which exhibits high charge transportability, high transparency and high refractive index. We have found that an organic EL device having excellent properties can be obtained when this thin film is applied to a hole injection layer or the like, and completed the present invention.

That is, the present invention provides the following fluorene derivatives and their uses.
1. 1. A fluorene derivative represented by the following formula (1).

[In the formula, Z ¹ and Z ² are groups represented by any of the following formulas (2) to (7) independently;

(Wherein, a broken line is a bond .R ^A and R ^B are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.)
Ar ¹ and Ar ² are independently an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, and are a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, and 1 carbon atom. Alkyl group of ~ 20, cycloalkyl group of 3 to 20 carbons, bicycloalkyl group of 4 to 20 carbons, alkoxy group of 2 to 20 carbons, alkynyl group of 2 to 20 carbons or alkynyl group of 1 to 20 carbons May be substituted with an alkoxy group;
Ar ³ and Ar ⁴ are groups represented by any of the following formulas (8) to (11) independently.

(In the formula, the broken line is the join hand,
R ¹ is substituted with a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkyl halide group having 1 to 20 carbon atoms. A heteroaryl group having 6 to 20 carbon atoms, or a heteroaryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group having 1 to 20 carbon atoms or an alkyl halide group having 1 to 20 carbon atoms, or the following. A group represented by any of the formulas (12) to (14).
R ² to R ⁵² are independently hydrogen atoms, cyano groups, nitro groups, halogen atoms, alkyl groups having 1 to 20 carbon atoms, or alkyl halide groups having 1 to 20 carbon atoms.

(In the formula, the broken line is the join hand,
D ^A is a diarylamino group each aryl group is independently C 6 -C 20 -aryl group,
R ⁵³ to R ⁷⁶ are independently hydrogen atoms, cyano groups, nitro groups, halogen atoms, alkyl groups having 1 to 20 carbon atoms, or alkyl halide groups having 1 to 20 carbon atoms. ))]
2. Ar ¹ and Ar ² are independently phenyl group, 1-naphthyl group or 2-naphthyl group, or the following formulas (T1-1) to (T11-4), formulas (F1-1) to (F4-4). ), The fluorene derivative of 1 which is a group represented by the formulas (N1-1) to (N10-7) or the formulas (M1-1) to (M4-3).

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)
3. 3. A fluorene derivative of 1 or 2 in which Ar ¹ and Ar ² are the same group.
4. A fluorene derivative according to any one of 1 to 3, wherein Z ¹ and Z ² are groups represented by the formula (2).
5. A fluorene derivative in which R ¹ is a phenyl group.
6. A fluorene derivative in which R ² to R ⁷⁶ is a hydrogen atom.
A charge-transporting substance comprising a fluorene derivative according to any one of 7.1 to 6.
A charge-transporting varnish containing a charge-transporting substance and an organic solvent of 8.7.
9. In addition, 8 charge transport varnishes containing dopants.
A charge transport thin film obtained from a charge transport varnish of 10.8 or 9.
An organic EL device including a charge transporting thin film of 11.10.
12. The compound represented by the formula (15) is reacted with the compound represented by the formula (16-1) and the compound represented by the formula (16-2) to obtain an intermediate represented by the formula (17). Process,
The step of reducing the intermediate represented by the formula (17) to obtain the intermediate represented by the formula (18), and the intermediate represented by the formula (18) and the intermediate represented by the formula (19-1). A method for producing a fluorene derivative represented by the following formula (1), which comprises a step of reacting a halide with a halide represented by the formula (19-2).

(In the formula, Z ¹ , Z ² , Ar ¹ , Ar ² , Ar ³ and Ar ⁴ are the same as above; X is a halogen atom or pseudohalogen group.)

By using the charge-transporting varnish containing the fluorene derivative of the present invention, a thin film having high transparency and high refractive index can be produced, and a thin film having excellent charge transportability even when fired at a low temperature of 200 ° C. or lower. Can be produced. The charge-transporting thin film obtained from the charge-transporting varnish of the present invention can be suitably used as a thin film for electronic devices such as organic EL devices, and the hole injection layer and the hole transport layer of the organic EL device, particularly By using it as a hole injection layer, an organic EL device having excellent characteristics can be obtained.

[Fluorene derivative]
The fluorene derivative of the present invention is represented by the following formula (1).

Examples of the compound represented by the formula (1) include, but are not limited to, those shown below.

In formula (1), Z ¹ and Z ² are groups represented by any of the following formulas (2) to (7) independently. When Z ¹ and Z ² are groups represented by the formula (4) or (5), the carbon atom contained in this group is bonded to the nitrogen atom in the formula (1).

In the equations (2) to (7), the broken line is the connecting hand. Wherein (6), R ^A and R ^B are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, a hydrogen atom is preferable.

Alkyl groups R ^A and 1 to 20 carbon atoms represented by R ^B is a linear, branched, may be any of cyclic, and examples thereof include a methyl group, an ethyl group, n- propyl group, isopropyl Group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, etc. Linear or branched alkyl group having 1 to 20 carbon atoms; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, bicyclobutyl group, bicyclopentyl group , Bicyclohexyl group, bicycloheptyl group, bicyclooctyl group, bicyclononyl group, bicyclodecyl group and other cyclic alkyl groups having 3 to 20 carbon atoms.

As Z ¹ and Z ² , the groups represented by the formulas (2), (3), (4), (5) or (6) are preferable, and the groups represented by the formulas (2), (4) or (6) are represented. The group represented by the formula (2) is more preferable, and the group represented by the formula (2) is even more preferable.

In the formula (1), Ar ¹ and Ar ² are independently aryl groups having 6 to 20 carbon atoms or heteroaryl groups having 2 to 20 carbon atoms.

Examples of the aryl group having 6 to 20 carbon atoms represented by Ar ¹ and Ar ² include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group and a 1-. Examples thereof include a phenanthryl group, a 2-phenanthril group, a 3-phenanthril group, a 4-phenylantril group, a 9-phenanthril group and the like.

Examples of the heteroaryl group having 2 to 20 carbon atoms represented by Ar ¹ and Ar ² include the following formulas (T1-1) to (T11-4), formulas (F1-1) to (F4-4), and formulas (F4-4). Examples thereof include groups represented by N1-1) to (N10-7) and formulas (M1-1) to (M4-3), but the present invention is not limited thereto. Among them, from the viewpoint of realizing a higher refractive index, the sulfur-containing heteroaryl group and the nitrogen-containing heteroaryl group are preferable, and the sulfur-containing heteroaryl group is more preferable.

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

The aryl group having 6 to 20 carbon atoms or the heteroaryl group having 2 to 20 carbon atoms represented by Ar ¹ and Ar ² has a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group and 1 to 20 carbon atoms. It may be substituted with an alkyl group, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

Alkyl group having 1 to 20 carbon atoms may be linear, branched, may be any of cyclic, and examples thereof include those of formula similar to that described in the description of R ^A and R ^B (6) Can be mentioned.

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

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 and an n-1. -Butynyl group, n-2-butynyl group, n-3-butynyl group, 1-methyl-2-propynyl group, n-1-pentynyl group, n-2-pentynyl group, n-3-pentynyl group, n- 4-pentynyl group, 1-methyl-n-butynyl group, 2-methyl-n-butynyl group, 3-methyl-n-butynyl group, 1,1-dimethyl-n-propynyl group, n-1-hexynyl group, Examples thereof include an n-1-decynyl group, an n-1-pentadecynyl group, and an n-1-eicosynyl group.

The alkoxy group having 1 to 20 carbon atoms may be linear, branched or cyclic, and specific examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group and an n-butoxy group. Number of carbon atoms of isobutoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, etc. 1 to 20 linear or branched alkoxy groups; cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group, cycloheptyloxy group, cyclooctyloxy group, cyclononyloxy group, cyclodecyloxy group , Bicyclobutyloxy group, bicyclopentyloxy group, bicyclohexyloxy group, bicycloheptyloxy group, bicyclooctyloxy group, bicyclononyloxy group, bicyclodecyloxy group and other cyclic alkoxy groups having 3 to 20 carbon atoms.

Of these, Ar ¹ and Ar ² include phenyl group; nitrophenyl group; methylphenyl group, ethylphenyl group, propylphenyl group, dimethylphenyl group, diethylphenyl group, dipropylphenyl group, trimethylphenyl group, and triethylphenyl. Group, tripropylphenyl group, alkylphenyl group such as these structural isomers; alkenylphenyl group such as vinylphenyl group, 1-propenylphenyl group, 2-propenylphenyl group; ethynylphenyl group, 1-propynylphenyl group, 2 -Alquinylphenyl group such as propynylphenyl group; 1-naphthyl group; nitro-1-naphthyl group; methyl-1-naphthyl group, ethyl-1-naphthyl group, propyl-1-naphthyl group, dimethyl-1-naphthyl group, Diethyl-1-naphthyl group, dipropyl-1-naphthyl group, trimethyl-1-naphthyl group, triethyl-1-naphthyl group, tripropyl-1-naphthyl group, alkyl-1-naphthyl group such as these structural isomers; Alkenyl-1-naphthyl groups such as vinyl-1-naphthyl group, 1-propenyl-1-naphthyl group, 2-propenyl-1-naphthyl group; ethynyl-1-naphthyl group, 1-propynyl-1-naphthyl group, 2 -Alkinyl-1-naphthyl group such as propynyl-1-naphthyl group; 2-naphthyl group; nitro-2-naphthyl group; methyl-2-naphthyl group, ethyl-2-naphthyl group, propyl-2-naphthyl group, dimethyl Alkyl of -2-naphthyl group, diethyl-2-naphthyl group, dipropyl-2-naphthyl group, trimethyl-2-naphthyl group, triethyl-2-naphthyl group, tripropyl-2-naphthyl group, structural isomers of these, etc. -2-naphthyl group; alkenyl-2-naphthyl group such as vinyl-2-naphthyl group, 1-propenyl-2-naphthyl group, 2-propenyl-2-naphthyl group; ethynyl-2-naphthyl group, 1-propynyl- Alkinyl-2-naphthyl groups such as 2-naphthyl group and 2-propynyl-2-naphthyl group; 9-anthryl group, 1-phenyl group, 2-phenyl group, 3-phenyl group, 9-phenyl group; formula (T1). The groups represented by -1) to (T11-4) are preferable. Further, Ar ¹ and Ar ² are preferably the same group from the viewpoint of easiness of synthesizing the fluorene derivative.

In the formula (1), Ar ³ and Ar ⁴ are groups represented by any of the following formulas (8) to (11) independently.

In the equations (8) to (11), the broken line is the joiner. In formula (8), R ¹ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl halide having 1 to 20 carbon atoms. An aryl group having 6 to 20 carbon atoms which may be substituted with a group, or an alkyl group having 1 to 20 carbon atoms or an alkyl halide having 1 to 20 carbon atoms which may be substituted with an alkyl group having 6 to 20 carbon atoms. It is a heteroaryl group or a group represented by any of the following formulas (12) to (14).

In the equations (12) to (14), the broken line is the joiner. D ^A is a diarylamino group each aryl group is independently C 6 -C 20 -aryl group.

Examples of the alkyl group having 1 to 20 carbon atoms is an alkyl group and the substituent group having 1 to 20 carbon atoms represented by R ^1, the same as those described in the description of R ^A and R ^B of formula (6) Things can be mentioned. Examples of the aryl group having 6 to 20 carbon atoms represented by R ¹ include those similar to those described in the description of Ar ¹ and Ar ² of the formula (1). The heteroaryl group having 2 to 20 carbon atoms represented by R ¹ includes 2-thienyl group, 3-thienyl group, 2-furanyl group, 3-furanyl group, 2-oxazolyl group, 4-oxazolyl group and 5-. Oxazolyl group, 3-isooxazolyl group, 4-isooxazolyl group, 5-isooxazolyl group, 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isothiazolyl group, 4-isothiazolyl group, 5-isothiazolyl group, 2- Examples thereof include an imidazolyl group, a 4-imidazolyl group, a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group and the like.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like. Examples of the alkyl halide group having 1 to 20 carbon atoms include those in which a part or all of the hydrogen atoms of the alkyl group having 1 to 20 carbon atoms are substituted with the halogen atom. In the description of (B), the same ones as those described later can be mentioned. Examples of the diarylamino group include a diphenylamino group, a dinaphthylamino group, a dianthrylamino group, an N-phenyl-N-naphthylamino group, an N-phenyl-N-anthrylamino group, and an N-naphthyl-N-anthryl. Amino groups and the like can be mentioned.

As the group represented by the formulas (12) to (14), those represented by the following formulas (12-1) to (14-1) are preferable.

Of these, R ¹ includes a hydrogen atom, a phenyl 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, and a 2-phenanthryl group. 3-Phenyltril group, 4-Phenyltril group, 9-Phenyltril group, group represented by the formula (12-1), group represented by the formula (13-1) and the like are preferable, and the group represented by the formula (12-1) is preferable. The group to be used, the group represented by the formula (13-1) and the phenyl group are more preferable, and the phenyl group is even more preferable.

In formulas (8) to (14), R ² to R ⁷⁶ are independently hydrogen atoms, cyano groups, nitro groups, halogen atoms, alkyl groups having 1 to 20 carbon atoms, or halogenated groups having 1 to 20 carbon atoms. It is an alkyl group. The alkyl group of R ² ~ 1 to 20 carbon atoms represented by R ^76, include the same ones as mentioned in the description of R ^A and R ^B of formula (6). Of these, as R ² to R ⁷⁶ , a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 10 carbon atoms or an alkyl halide group having 1 to 10 carbon atoms are preferable, and a hydrogen atom and a cyano group are used. A group, a nitro group, a halogen atom and a trifluoromethyl group are more preferable, and it is even more preferable that all of them are hydrogen atoms.

Examples of the groups represented by the formulas (8) to (11) include, but are not limited to, those shown below.

(In the formula, R ¹ to R ⁵² are the same as above. The broken line is the connecting hand.)

As the groups represented by the formulas (8) to (11), those shown below are particularly preferable.

(In the formula, the broken line is the joiner.)

[Method for synthesizing fluorene derivatives]
The fluorene derivative of the present invention can be synthesized by the method shown in Scheme A below.

(In the formula, Z ¹ , Z ² , Ar ¹ , Ar ² , Ar ³ and Ar ⁴ are the same as above. X is a halogen atom or a pseudohalogen group.)

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like. The pseudo-halogen group includes a fluoroalkylsulfonyloxy group such as a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group and a nonafluorobutanesulfonyloxy group; and an aromatic sulfonyloxy group such as a benzenesulfonyloxy group and a toluenesulfonyloxy group. And so on.

The compound represented by the formula (15) can be synthesized by a conventionally known method, for example, according to the method described in J. Mater. Chem. C, 2014, pp. 1068-1075.

In Scheme A, the first step is carried out by a coupling reaction from the compound represented by the formula (15), the compound represented by the formula (16-1) and the compound represented by the formula (16-2). This is a step of obtaining an intermediate represented by the formula (17). In Scheme A, a synthesis method using the Suzuki-Miyaura coupling reaction is shown as an example, but it is also possible to synthesize using another coupling reaction.

The catalysts used in the Suzuki-Miyaura coupling reaction are [1,1'-bis (diphenylphosphino) ferrocene] palladium (II) dichloride (PdCl ₂ (dppf)), tetrakis (triphenylphosphine) palladium (Pd (PPh)). ₃ ) ₄ ), bis (triphenylphosphine) dichloropalladium (Pd (PPh ₃ ) ₂ Cl ₂ ), bis (benzylideneacetone) palladium (Pd (dba) ₂ ), tris (benzylideneacetone) dipalladium (Pd ₂ (dba)) ) ₃ ), Palladium catalysts such as bis (tritert-butylidphosphine) palladium (Pd (Pt-Bu ₃ ) ₂ ) and palladium acetate (Pd (OAc) ₂ ). Of these, preferred catalysts are PdCl ₂ (dppf), Pd (PPh ₃ ) ₄ , Pd (PPh ₃ ) ₂ Cl ₂ , and Pd (Pt-Bu ₃ ) ₂ from the viewpoint of efficiently obtaining the desired product. More preferably, it is Pd (PPh ₃ ) ₄ and Pd (Pt-Bu ₃ ) ₂ . The amount of the catalyst used is usually about 0.1 to 50 mol%, preferably 0.1 to 30 mol%, and more preferably 1 to 10 mol% with respect to the compound represented by the formula (15).

In addition, a base is also used in the Suzuki-Miyaura coupling reaction, and the base includes hydroxides such as sodium hydroxide, potassium hydroxide and cesium hydroxide, tert-butoxysodium, tert-butoxypotassium and the like. Alkoxides; Fluoride salts such as lithium fluoride, potassium fluoride, cesium fluoride; carbonates such as lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, etc .; Examples thereof include amines such as phosphates, trimethylamine, triethylamine, diisopropylamine, n-butylamine and diisopropylethylamine. Of these, preferable bases are carbonates such as sodium carbonate, potassium carbonate, cesium carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate, and phosphates such as potassium phosphate from the viewpoint of efficiently obtaining the desired product. Potassium carbonate and cesium carbonate are preferable. The amount of the base used is usually about 2 to 20 equivalents, preferably 1 to 20 equivalents, and more preferably 2 to 8 equivalents, relative to the compound represented by the formula (15).

The solvent used in the first step is not particularly limited as long as it does not adversely affect the reaction, but specific examples thereof 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, mecitylene, etc.), ether (Diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran (THF), dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc.), amide (N, N-dimethylformamide (DMF), N , N-dimethylacetamide, etc.), lactam and lactone (N-methylpyrrolidone, γ-butyrolactone, etc.), urea derivatives (N, N-dimethylimidazolidinone, tetramethylurea, etc.), sulfoxides (dimethyl sulfoxide, sulfolane, etc.), Examples thereof include nitriles (acetoyl, propionitrile, butyronitrile, etc.). Of these, preferred solvents are aliphatic hydrocarbons (pentane, n-hexane, n-octane, n-decane, decalin, etc.) and aromatic hydrocarbons (benzene, nitrobenzene, toluene, etc.) from the viewpoint of efficiently obtaining the desired product. , O-Xylene, m-xylene, p-xylene, mesitylene, etc.), ether (diethyl ether, diisopropyl ether, tert-butylmethyl ether, THF, dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc. ), More preferably aromatic hydrocarbons (benzene, nitrobenzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, etc.), ethers (diethyl ether, diisopropyl ether, tert-butyl methyl ether, THF, Dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc.).

The charging ratio of the compound represented by the formula (15) to the compound represented by the formula (16-1) and the compound represented by the formula (16-2) is based on the compound represented by the formula (15). , The total of the compound represented by the formula (16-1) and the compound represented by the formula (16-2) is preferably 2 to 6 equivalents, and more preferably 2 to 3 equivalents. The compound represented by the formula (16-1) and the compound represented by the formula (16-2) may be the same or different from each other.

In the first step, the reaction temperature is appropriately set in the range from the melting point to the boiling point of the solvent while considering the type and amount of the raw material compound and the catalyst to be used, but is usually about 0 to 200 ° C., preferably 0. ~ 50 ° C. The reaction time cannot be unconditionally specified because it varies depending on the raw material compound used, the reaction temperature, and the like, but it is usually about 1 to 24 hours.

In Scheme A, the second step is a step of reducing the intermediate represented by the formula (17) to obtain the intermediate represented by the formula (18). Examples of the reducing method include known methods such as catalytic hydrogenation and chemical reduction with a metal and an acid.

When reduction is performed by catalytic hydrogenation, known catalysts such as palladium carbon, Raney nickel catalyst, platinum oxide, ruthenium carbon, rhodium carbon, and platinum carbon may be used. The conditions for catalytic hydrogenation include, for example, a hydrogen pressure of 1 to 10 atm, a reaction temperature of 20 to 100 ° C., and a reaction time of 1 to 48 hours.

In Scheme A, the third step is to react the intermediate represented by the formula (18) with the compound represented by the formula (19-1) and the compound represented by the formula (19-2). This is a step of synthesizing the fluorene derivative represented by (1).

A base may be used in the third step. Examples of the base include those similar to those that can be used in the first step. Of these, triethylamine, pyridine, diisopropylethylamine and the like are preferable because they are particularly easy to handle.

The reaction solvent is preferably an aprotic organic solvent, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, tetrahydrofuran, Examples thereof include dioxane. From the viewpoint of easy removal of the reaction solvent after the reaction, N, N-dimethylformamide, N, N-dimethylacetamide, tetrahydrofuran, dioxane, toluene, xylene, mesitylene and the like are preferable.

The charging ratio of the intermediate represented by the formula (18) to the compound represented by the formula (19-1) and the compound represented by the formula (19-2) is the intermediate represented by the formula (18). On the other hand, the total of the compound represented by the formula (19-1) and the compound represented by the formula (19-2) is preferably 2 to 6 equivalents, and more preferably 2 to 3 equivalents. The compound represented by the formula (19-1) and the compound represented by the formula (19-2) may be the same as or different from each other.

In the third step, the reaction temperature is appropriately set in the range from the melting point to the boiling point of the solvent while considering the type and amount of the raw material compound and the catalyst to be used, but is usually about 0 to 200 ° C., preferably 0. ~ 50 ° C. The reaction time cannot be unconditionally specified because it varies depending on the raw material compound used, the reaction temperature, and the like, but it is usually about 1 to 24 hours.

After completion of the reaction, post-treatment can be performed according to a conventional method to obtain the desired fluorene derivative.

The compound represented by the formula (19-1) and the compound represented by the formula (19-2) can be obtained by a known method or the availability of a commercially available product.

[Charge transporting substance]
The fluorene derivative of the present invention can be suitably used as a charge transporting substance, particularly as a hole transporting substance. In the present invention, charge transportability is synonymous with conductivity. A charge-transporting substance is a substance that has a charge-transporting property in itself. Further, the charge-transporting varnish itself may have a charge-transporting property, and the solid film obtained thereby may have a charge-transporting property.

[Charge transport varnish]
The charge-transporting varnish of the present invention contains a charge-transporting substance composed of the fluorene derivative and an organic solvent. The charge transporting substance may be used alone or in combination of two or more.

[Organic solvent]
As the organic solvent, a highly polar solvent capable of satisfactorily dissolving the fluorene derivative can be used. The fluorene derivative of the present invention can be dissolved in a solvent regardless of the polarity of the solvent. Further, if necessary, a low-polarity solvent may be used because it is superior in process compatibility to a high-polarity solvent. In the present invention, a low-polarity solvent is defined as having a relative permittivity of less than 7 at a frequency of 100 kHz, and a high-polarity solvent is defined as having a relative permittivity of 7 or more at a frequency of 100 kHz.

Examples of the low polar solvent include chlorine-based solvents such as chloroform and chlorobenzene; aromatic hydrocarbon-based solvents such as toluene, xylene, tetraline, cyclohexylbenzene and decylbenzene; 1-octanol, 1-nonanol, 1-decanol and the like. Alibo alcohol solvents; ethers such as tetrahydrofuran, dioxane, anisole, 4-methoxytoluene, 3-phenoxytoluene, dibenzyl ether, diethylene glycol dimethyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, etc. Solvents: methyl benzoate, ethyl benzoate, butyl benzoate, isoamyl benzoate, bis (2-ethylhexyl) phthalate, dibutyl maleate, dibutyl oxalate, hexyl acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, etc. Examples thereof include ester solvents.

Examples of the highly polar solvent include amides such as N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethylisobutylamide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolidinone. System solvent; Ketone solvent such as ethyl methyl ketone, isophorone, cyclohexanone; Cyano solvent such as acetonitrile and 3-methoxypropionitrile; Ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-butanediol, Polyhydric alcohol solvents such as 2,3-butanediol; diethylene glycol monomethyl ether, diethylene glycol monophenyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, benzyl alcohol, 2-phenoxyethanol, 2-benzyloxyethanol, 3- Monovalent alcohol-based solvents other than aliphatic alcohols such as phenoxybenzyl alcohol and tetrahydrofurfuryl alcohol; sulfoxide-based solvents such as dimethyl sulfoxide, and the like can be mentioned.

The amount of the solvent used is such that the solid content concentration in the varnish of the present invention is usually about 0.1 to 20% by mass, preferably from the viewpoint of ensuring a sufficient film thickness while suppressing the precipitation of the charge transporting substance. The amount is 0.5 to 10% by mass. The solid content as used herein means a component other than the solvent among the components contained in the varnish. The solvent may be used alone or in combination of two or more.

[Dopant (charge-accepting dopant)]
The charge-transporting varnish of the present invention may contain a dopant for the purpose of improving the charge-transporting property of the thin film obtained from the charge-transporting varnish of the present invention. The dopant is not particularly limited as long as it is soluble in at least one solvent used in the composition, and either an inorganic dopant or an organic dopant can be used. Further, in the process of obtaining a charge-transporting thin film which is a solid film from the composition, the dopant first develops its function as a dopant by removing a part of the molecule due to an external stimulus such as heating at the time of firing. It may be a substance that improves, for example, an aryl sulfonic acid ester compound protected by a group in which a sulfonic acid group is easily eliminated.

Heteropolyacid is preferable as the inorganic dopant, and specific examples thereof include phosphomolybdic acid, silicate molybdic acid, phosphotungstic acid, phosphotungstic acid, and silicate tungstic acid.

The heteropolyacid has a structure in which the hetero atom is located at the center of the molecule, which is typically represented by a Keggin type represented by the following formula (HPA1) or a Dawson type chemical structure represented by the following formula (HPA2). However, it is a polyacid formed by condensing an isopolyacid, which is an oxygen acid such as vanadium (V), molybdenum (Mo), and tungsten (W), and an oxygen acid of a different element. Oxygen acids of such dissimilar elements mainly include oxygen acids of silicon (Si), phosphorus (P), and arsenic (As).

Examples of the heteropolyacid include phosphomolybdic acid, silicate molybdic acid, phosphotungstic acid, silicate tungstic acid, and phosphotungstic acid. These may be used individually by 1 type or in combination of 2 or more type. The heteropolyacid used in the present invention is available as a commercially available product, and can also be synthesized by a known method. In particular, when one kind of heteropolyacid is used, the one kind of heteropolyacid is preferably phosphotungstic acid or phosphomolybdic acid, and phosphotungstic acid is most suitable. When two or more kinds of heteropolyacids are used, one of the two or more kinds of heteropolyacids is preferably phosphotungstic acid or phosphomolybdic acid, and more preferably phosphotungstic acid.

In addition, in quantitative analysis such as elemental analysis, heteropolyacids are those obtained as commercial products or known synthetics even if the number of elements is large or small from the structure represented by the general formula. As long as it is properly synthesized according to the method, it can be used in the present invention.

That is, for example, phosphotungsten acid is generally represented by the chemical formulas H ₃ (PW ₁₂ O ₄₀ ) and nH ₂ O, and phosphomolybdic acid is generally represented by the chemical formulas H ₃ (PMo ₁₂ O ₄₀ ) and nH ₂ O. In the quantitative analysis, even if the number of P (phosphorus), O (oxygen) or W (tungsten) or Mo (molybdenum) in this formula is large or small, it is obtained as a commercial product, or As long as it is appropriately synthesized according to a known synthesis method, it can be used in the present invention. In this case, the mass of the heteropolyacid defined in the present invention is not the mass of pure phosphotungstic acid (phosphotungstic acid content) in the synthetic product or the commercially available product, but the form available as the commercially available product and the known synthesis. In a form that can be isolated by the method, it means the total mass in a state containing hydrated water and other impurities.

Examples of the organic dopant include aryl sulfonic acid, aryl sulfonic acid ester, an ionic compound composed of a predetermined anion and its counter cation, a tetracyanoquinodimethane derivative, a benzoquinone derivative and the like.

The aryl sulfonic acid compound is preferably represented by the following formula (A) or (B) from the viewpoint of the transparency of the thin film obtained from the charge transporting varnish of the present invention.

In the formula (A), A ¹ is -O- or -S-, but -O- is preferable. A ² is a (p ² + 1) -valent group derived from naphthalene or anthracene (ie, a group obtained by removing p ² + 1 hydrogen atoms from naphthalene or anthracene), but is derived from naphthalene. A group is preferred. A ³ is a 2- to 4-valent perfluorobiphenyl group. p ¹ is the number of bonds between A ¹ and A ^3, and is an integer satisfying 2 ≤ p ¹ ≤ 4, but A ³ is a divalent perfluorobiphenyl group and p ¹ is 2. Is preferable. p ² is the number of sulfonic acid groups bonded to A ² , and is an integer satisfying 1 ≦ p ² ≦ 4, but 2 is preferable.

In the formula (B), A ⁴ to A ⁸ are independently hydrogen atom, halogen atom, cyano group, alkyl group having 1 to 20 carbon atoms, alkyl halide group having 1 to 20 carbon atoms or 2 to 2 carbon atoms, respectively. There are 20 halogenated alkenyl groups, but at least 3 of A ⁴ to A ⁸ are halogen atoms. q is the number of sulfonic acid groups bonded to the naphthalene ring and is an integer satisfying 1 ≦ q ≦ 4, but 2 to 4 is preferable, and 2 is more preferable.

Examples of the alkyl halide group having 1 to 20 carbon atoms include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, and a 3,3,3-trifluoropropyl group, 2,2, 3,3,3-Pentafluoropropyl group, perfluoropropyl group, 4,4,4-trifluorobutyl group, 3,3,4,4,4-pentafluorobutyl group, 2,2,3,3, Examples thereof include 4,4,4-heptafluorobutyl group and perfluorobutyl group. Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include a perfluoroethenyl group, a 1-perfluoropropenyl group, a perfluoroallyl group, a perfluorobutenyl group and the like.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable. The alkyl group having 1 to 20 carbon atoms include the same ones as mentioned in the description of R ^A and R ^B of formula (6).

Among these, A ⁴ to A ⁸ include hydrogen atom, halogen atom, cyano group, alkyl group having 1 to 10 carbon atoms, alkyl halide group having 1 to 10 carbon atoms, or alkenyl halide having 2 to 10 carbon atoms. a group, and it is preferable that at least three fluorine atoms of a ⁴ - a ^8, a hydrogen atom, a fluorine atom, fluorinated cyano group, an alkyl group having 1 to 5 carbon atoms, 5 It is more preferably an alkyl group or a fluorinated alkenyl group having 2 to 5 carbon atoms, and at least 3 of A ⁴ to A ⁸ are fluorine atoms, and a hydrogen atom, a fluorine atom, a cyano group, and 1 to 1 carbon atoms. It is even more preferable that it is a perfluoroalkyl group of 5 or a perfluoroalkenyl group having 1 to 5 carbon atoms, and that A ⁴ , A ⁵ and A ⁸ are fluorine atoms. The perfluoroalkyl group is a group in which all the hydrogen atoms of the alkyl group are substituted with fluorine atoms, and the perfluoroalkyl group is a group in which all the hydrogen atoms of the alkenyl group are substituted with fluorine atoms.

Specific examples of suitable aryl sulfonic acids include, but are not limited to, those shown below.

As the aryl sulfonic acid ester compound, the aryl sulfonic acid ester compound disclosed in International Publication No. 2017/217455, International Publication No. 2017/217457, from the viewpoint of the transparency of the thin film obtained from the charge transport varnish of the present invention. Examples thereof include the aryl sulfonic acid ester compound disclosed in No. 2, the aryl sulfonic acid ester compound described in Japanese Patent Application No. 2017-243631 and the like.

Specifically, from the viewpoint of solubility in a low-polarity solvent, the aryl sulfonic acid ester compound is preferably represented by any of the following formulas (C) to (E).

In the formulas (C) to (E), m is an integer satisfying 1 ≦ m ≦ 4, but 2 is preferable. n is an integer satisfying 1 ≦ n ≦ 4, but 2 is preferable.

In formula (C), A ¹¹ is an m-valent group derived from perfluorobiphenyl (ie, a group obtained by removing m fluorine atoms from perfluorobiphenyl). A ¹² is —O— or —S—, but —O— is preferred. A ¹³ is a (n + 1) -valent group derived from naphthalene or anthracene (that is, a group obtained by removing n + 1 hydrogen atoms from naphthalene or anthracene), but a group derived from naphthalene is preferable. R ^s1 to R ^s4 are independently hydrogen atoms or linear or branched alkyl groups having 1 to 6 carbon atoms, and R ^s5 has 2 to 20 carbon atoms which may be substituted. It is a monovalent hydrocarbon group.

The linear or branched alkyl group having 1 to 6 carbon atoms represented by R ^s1 to R ^s4 includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and sec. -Butyl group, tert-butyl group, n-hexyl group and the like can be mentioned. Of these, an alkyl group having 1 to 3 carbon atoms is preferable.

The monovalent hydrocarbon group having 2 to 20 carbon atoms represented by R ^s5 may be linear, branched or cyclic, and specific examples thereof include an ethyl group, an n-propyl group, an isopropyl group and n. -Alkyl groups such as butyl group, isobutyl group, sec-butyl group and tert-butyl group; aryl groups such as phenyl, naphthyl and phenanthryl groups can be mentioned.

In particular, among R ^s1 to R ^s4 , R ^s1 or R ^s3 is a linear alkyl group having 1 to 3 carbon atoms, and the rest is a hydrogen atom, or R ^s1 is a linear alkyl group having 1 to 3 carbon atoms. It is preferable that R ^s2 to R ^s4 are hydrogen atoms. In this case, the methyl group is preferable as the linear alkyl group having 1 to 3 carbon atoms. Further, as R ^s5 , a linear alkyl group or a phenyl group having 2 to 4 carbon atoms is preferable.

In the formula (D), A ¹⁴ is an m-valent hydrocarbon group having 6 to 20 carbon atoms containing one or more aromatic rings which may be substituted, and the hydrocarbon group may be one or more. It is a group obtained by removing m hydrogen atoms from a hydrocarbon compound having 6 to 20 carbon atoms containing an aromatic ring. Examples of the hydrocarbon compound include benzene, toluene, xylene, ethylbenzene, biphenyl, naphthalene, anthracene, phenanthrene and the like.

In the hydrocarbon group represented by A ¹⁴ , a part or all of the hydrogen atom may be further substituted with a substituent, and such substituents include a fluorine atom, a chlorine atom and a bromine atom. , Iodine atom, nitro group, cyano group, hydroxy group, amino group, silanol group, thiol group, carboxy group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, ester group, thioester group, amide group, monovalent Examples thereof include a hydrocarbon group, an organooxy group, an organoamino group, an organosilyl group, an organothio group, an acyl group and a sulfo group. Among these, as A ¹⁴ , a group derived from benzene, biphenyl or the like is preferable.

In formula (D), A ¹⁵ is —O— or —S—, but —O— is preferred.

In the formula (D), A ¹⁶ is an (n + 1) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and this aromatic hydrocarbon group is the aroma of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. It is a group obtained by removing (n + 1) hydrogen atoms from the ring. Examples of the aromatic hydrocarbon compound include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene and the like. Among them, as A ¹⁶ , a group derived from naphthalene or anthracene is preferable, and a group derived from naphthalene is more preferable.

In formula (D), R ^s6 and R ^s7 are independently hydrogen atoms or linear or branched monovalent aliphatic hydrocarbon groups, and R ^s8 is linear or branched. It is a monovalent aliphatic hydrocarbon group. However, the total number of carbon atoms of R ^s6 , R ^s7 and R ^s8 is 6 or more. The upper limit of the total number of carbon atoms of R ^s6 , R ^s7 and R ^s8 is not particularly limited, but is preferably 20 or less, and more preferably 10 or less.

Specific examples of the linear or branched monovalent aliphatic hydrocarbon group represented by R ^s6 , R ^s7 and R ^s8 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and an n-butyl group. , Isobutyl group, sec-butyl group, tert-butyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, decyl group and other alkyl groups having 1 to 20 carbon atoms; vinyl group, 1-propenyl group, Examples thereof include alkenyl groups having 2 to 20 carbon atoms such as 2-propenyl group, isopropenyl group, 1-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group and hexenyl group. Among these, R ^s6 is preferably a hydrogen atom, and R ^s7 and R ^s8 are each independently preferably an alkyl group having 1 to 6 carbon atoms.

In the formula (E), R ^s9 to R ^s13 are independently hydrogen atom, nitro group, cyano group, halogen atom, alkyl group having 1 to 10 carbon atoms, and alkyl halide group having 1 to 10 carbon atoms, respectively. Alternatively, it is a halogenated alkenyl group having 2 to 10 carbon atoms.

The alkyl group having 1 to 10 carbon atoms represented by R ^s9 to R ^s13 may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, cyclopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, n-nonyl group , N-decyl group and the like.

The alkyl halide group having 1 to 10 carbon atoms represented by R ^s9 to R ^s13 is particularly a group in which a part or all of the hydrogen atoms of the alkyl group having 1 to 10 carbon atoms are substituted with a halogen atom. Not limited. Specific examples thereof include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, a 3,3,3-trifluoropropyl group, and a 2,2. 2,3,3,3-pentafluoropropyl group, 1,1,2,2,3,3,3-heptafluoropropyl group, 4,4,4-trifluorobutyl group, 3,3,4,4 , 4-Pentafluorobutyl group, 2,2,3,3,4,4,4-heptafluorobutyl group, 1,1,2,2,3,3,4,4,4-nonafluorobutyl group, etc. Can be mentioned.

The halogenated alkenyl group having 2 to 10 carbon atoms represented by R ^s9 to R ^s13 is a group in which some or all of the hydrogen atoms of the alkenyl group having 2 to 10 carbon atoms are substituted with halogen atoms. Specific examples thereof include, but are not limited to, a perfluorovinyl group, a perfluoro-1-propenyl group, a perfluoro-2-propenyl group, a perfluoro-1-butenyl group, a perfluoro-2-butenyl group, and a perfluoro. -3-Butenyl group and the like can be mentioned.

Among these, as R ^s9 , a nitro group, a cyano group, an alkyl halide group having 1 to 10 carbon atoms, and an alkenyl halide group having 2 to 10 carbon atoms are preferable, and a nitro group, a cyano group, and 1 to 4 carbon atoms are preferable. The alkyl halide group and the alkenyl halide group having 2 to 4 carbon atoms are more preferable, and the nitro group, the cyano group, the trifluoromethyl group and the perfluoropropenyl group are even more preferable. As R ^s10 to R ^s13 , a halogen atom is preferable, and a fluorine atom is more preferable.

In formula (E), A ¹⁷ is -O-, -S- or -NH-, but -O- is preferable.

In the formula (E), A ¹⁸ is an (n + 1) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and the aromatic hydrocarbon group is the aromatic of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. It is a group obtained by removing (n + 1) hydrogen atoms from the ring. Examples of the aromatic hydrocarbon compound include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene and the like. Among these, as A ¹⁸ , a group derived from naphthalene or anthracene is preferable, and a group derived from naphthalene is more preferable.

In the formula (E), R ^s14 to R ^s17 are independently hydrogen atoms or linear or branched monovalent aliphatic hydrocarbon groups having 1 to 20 carbon atoms. The monovalent aliphatic hydrocarbon group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group and a cyclopentyl group. , N-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group and other alkyl groups having 1 to 20 carbon atoms; vinyl Group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, hexenyl group, etc. having 2 to 20 carbon atoms Examples include alkenyl groups. Of these, an alkyl group having 1 to 20 carbon atoms is preferable, an alkyl group having 1 to 10 carbon atoms is more preferable, and an alkyl group having 1 to 8 carbon atoms is even more preferable.

In formula (E), R ^s18 is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or −OR ^s19 . R ^s19 is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted.

^Examples of the linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by R ^s18 include those similar to those described in the description of R ^s14 to R ^s17 . When R ^s18 is a monovalent aliphatic hydrocarbon group, R ^s18 is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and an alkyl group having 1 to 8 carbon atoms. Even more preferable.

As the monovalent hydrocarbon group having 2 to 20 carbon atoms represented by R ^s19 , in addition to the above-mentioned monovalent aliphatic hydrocarbon groups other than the methyl group, aryl groups such as phenyl, naphthyl and phenanthryl groups are used. Can be mentioned. Among these, R ^s19 is preferably a linear alkyl group or a phenyl group having 2 to 4 carbon atoms.

Examples of the substituent that the monovalent hydrocarbon group may have include a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group, and a cyano group.

Specific examples of suitable aryl sulfonic acid ester compounds include, but are not limited to, those shown below.

As the ionic compound composed of the predetermined anion and its counter cation, the ionic compound represented by the following formula (F) is preferable from the viewpoint of the transparency of the thin film obtained from the charge transporting varnish of the present invention.

In the formula (F), E is a Group 13 element of the long periodic table, and Ar ¹⁰¹ to Ar ¹⁰⁴ are independently aryl groups having 6 to 20 carbon atoms or heteroaryls having 2 to 20 carbon atoms. A group, such as a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom, an acyl group having 2 to 12 carbon atoms such as a cyano group, a nitro group or an acetyl group, or a halogen having 1 to 10 carbon atoms such as a trifluoromethyl group. It may be substituted with an alkylated group.

As the Group 13 element represented by E, a boron atom, an aluminum atom and a gallium atom are preferable, and a boron atom is more preferable. Examples of the aryl group having 6 to 20 carbon atoms represented by Ar ¹⁰¹ to Ar ¹⁰⁴ include the same aryl groups as those described in the description of Ar ¹ and Ar ^{2 in} the formula (1). Examples of the heteroaryl group having 2 to 20 carbon atoms represented by Ar ¹⁰¹ to Ar ¹⁰⁴ include a 2-thienyl group, a 3-thienyl group, a 2-furanyl group, a 3-furanyl group, a 2-oxazolyl group and a 4-oxazolyl group. , 5-Oxazolyl group, 3-isooxazolyl group, 4-isooxazolyl group, 5-isooxazolyl group, 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isothiazolyl group, 4-isothiazolyl group, 5-isothiazolyl group. , 2-Imidazolyl group, 4-imidazolyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group and the like.

In formula (F), M ⁺ is an onium ion. Examples of the onium ion include iodonium ion, sulfonium ion, ammonium ion, phosphonium ion and the like, and iodonium ion represented by the following formula (G) is particularly preferable.

In the formula (G), R ¹⁰¹ and R ¹⁰² independently have 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, and 6 to 20 carbon atoms, respectively. Aryl group or heteroaryl group having 2 to 20 carbon atoms, halogen atom, cyano group, nitro group, alkyl group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkynyl group having 2 to 12 carbon atoms. , It may be substituted with an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms.

Examples of the tetracyanoquinodimethane derivative include 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro. -7,7,8,8-Tetracyanoquinodimethane, Tetrafluoro-7,7,8,8-Tetracyanoquinodimethane (F4TCNQ), Tetrachloro-7,7,8,8-Tetracyanoquinodimethane Methane, 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2-chloro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8, Examples thereof include 8-tetracyanoquinodimethane, 2,5-dichloro-7,7,8,8-tetracyanoquinodimethane.

Examples of the benzoquinone derivative include tetrachloro-1,4-benzoquinone (chloranil), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and the like.

When the charge-transporting varnish of the present invention contains a dopant, the content thereof varies depending on the type of dopant, the desired charge-transporting property, and the like, and therefore cannot be unconditionally defined. However, it is a mass ratio with respect to the charge-transporting substance 1. It is usually about 0.01 to 50, preferably about 0.1 to 10, and more preferably about 1.0 to 5.0.

The charge-transporting varnish of the present invention may further contain an organic silane compound for the purpose of adjusting the film physical properties of the obtained charge-transporting thin film. Examples of the organic silane compound include a dialkoxysilane compound, a trialkoxysilane compound, and a tetraalkoxysilane compound. In particular, as the organic silane compound, a dialkoxysilane compound or a trialkoxysilane compound is preferable, and a trialkoxysilane compound is more preferable. The organic silane compound may be used alone or in combination of two or more.

When the organic silane compound is contained, its content is usually about 0.1 to 50% by mass with respect to the total mass of the charge-transporting substance and the dopant, but it suppresses a decrease in the charge-transporting property of the obtained thin film. In addition, it is intended to enhance the hole injection ability into a layer (for example, a hole transport layer or a light emitting layer) laminated on the opposite side of the anode so as to be in contact with the hole injection layer made of the charge transport thin film of the present invention. In consideration, it is preferably about 0.5 to 40% by mass, more preferably about 0.8 to 30% by mass, and even more preferably about 1 to 20% by mass.

The method for preparing the charge transporting varnish is not particularly limited, and examples thereof include a method in which the fluorene derivative and, if necessary, a dopant and the like are added to the organic solvent in any order or at the same time. When there are a plurality of organic solvents, the fluorene derivative and, if necessary, a dopant or the like may be first dissolved in one solvent, and another solvent may be added thereto, and the mixed solvent of the plurality of organic solvents may be used. The fluorene derivative and, if necessary, a dopant or the like may be dissolved sequentially or simultaneously.

In the charge transporting varnish of the present invention, from the viewpoint of obtaining a thin film having higher flatness with good reproducibility, the fluorene derivative and, if necessary, a dopant or the like are dissolved in an organic solvent, and then a filter or the like on the order of submicrometer is used. It is desirable to use and filter.

The viscosity of the charge-transporting varnish of the present invention is usually 1 to 50 mPa · s at 25 ° C. The surface tension of the charge-transporting varnish of the present invention is usually 20 to 50 mN / m at 25 ° C. The viscosity is a value measured by a TVE-25 type viscometer manufactured by Toki Sangyo Co., Ltd. The surface tension is a value measured by an automatic surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd. The viscosity and surface tension of the varnish can be adjusted by changing the types of solvents described above, their ratios, the solid content concentration, and the like in consideration of various factors such as a desired film thickness.

[Charge transport thin film]
The charge-transporting thin film of the present invention can be formed by applying the charge-transporting varnish of the present invention on a substrate and firing it.

Examples of the varnish coating method include, but are not limited to, the dip method, spin coating method, transfer printing method, roll coating method, brush coating, inkjet method, spray method, slit coating method, and the like. It is preferable to adjust the viscosity and surface tension of the varnish according to the coating method.

Further, the firing atmosphere of the charge-transporting varnish after coating is not particularly limited, and it is possible to obtain a thin film having a uniform film-forming surface and high charge-transporting property not only in the air atmosphere but also in an inert gas such as nitrogen or in a vacuum. it can. Depending on the type of dopant used together, a thin film having charge transportability may be obtained with good reproducibility by firing the varnish in an air atmosphere.

The firing temperature is appropriately set within the range of about 100 to 260 ° C. in consideration of the intended use of the obtained thin film, the degree of charge transportability applied to the obtained thin film, the type of solvent, the boiling point, etc., and the obtained thin film is obtained. When used as a hole injection layer for an organic EL element, it is preferably about 140 to 250 ° C., more preferably about 145 to 240 ° C., but the charge transporting varnish of the present invention has a good charge even at a low temperature of 200 ° C. or lower. A thin film having transportability can be obtained. At the time of firing, a temperature change of two or more steps may be applied for the purpose of developing higher uniform film forming property or advancing the reaction on the substrate, and heating may be performed by, for example, a hot plate or the like. It may be carried out using an appropriate device such as an oven.

The film thickness of the charge transporting thin film is not particularly limited, but is preferably 5 to 300 nm when used as a hole injection layer, a hole transport layer, or a hole transport layer of an organic EL element. As a method of changing the film thickness, there are methods such as changing the solid content concentration in the varnish and changing the amount of liquid on the substrate at the time of coating.

The charge-transporting thin film of the present invention exhibits a refractive index of 1.6 or more and an extinction coefficient of 0.030 or less on average in the wavelength region of 400 to 800 nm, but in some embodiments, a refraction of 1.65 or more. A rate, a refractive index of 1.70 or higher in some other embodiments, an extinction coefficient of 0.020 or less in some embodiments, and an extinction coefficient of 0.005 or less in other embodiments. Shown.

[Organic EL element]
The organic EL device of the present invention has a pair of electrodes, and has a functional layer made of the charge-transporting thin film of the present invention between these electrodes.

Typical configurations of the organic EL element include, but are not limited to, the following (a) to (f). In the following configuration, if necessary, an electron block layer or the like may be provided between the light emitting layer and the anode, and a hole block layer or the like may be provided between the light emitting layer and the cathode. Further, the hole injection layer, the hole transport layer or the hole injection transport layer may have a function as an electron block layer or the like, and the electron injection layer, the electron transport layer or the electron injection transport layer may serve as a hole block layer or the like. It may also have the functions of. Further, if necessary, an arbitrary functional layer can be provided between the layers.
(A) Antenna / 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) Electron / 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 / positive Hole injection layer / hole transport layer / light emitting layer / cathode (f) anode / hole injection transport layer / light emitting layer / cathode

The "hole injection layer", "hole transport layer" and "hole injection transport layer" are layers formed between the light emitting layer and the anode, and transport holes from the anode to the light emitting layer. It has a function. When only one layer of hole transporting material is provided between the light emitting layer and the anode, it is a "hole injection transport layer", and there are two layers of hole transporting material between the light emitting layer and the anode. When more than one layer is provided, the layer close to the anode is the "hole injection layer" and the other layers are the "hole transport layer". In particular, as the hole injection (transport) layer, a thin film having excellent not only hole acceptability from the anode but also hole injection property into the hole transport (emission) layer is used.

The "electron injection layer", "electron transport layer" and "electron transport layer" are layers formed between the light emitting layer and the cathode and have a function of transporting electrons from the cathode to the light emitting layer. Is. When only one layer of electron transporting material is provided between the light emitting layer and the cathode, it is an "electron injection transporting layer", and two or more layers of electron transporting material are provided between the light emitting layer and the cathode. If so, the layer close to the cathode is the "electron injection layer" and the other layers are the "electron transport layer".

The "light emitting layer" is an organic layer having a light emitting function, and includes a host material and a dopant material when a doping system is adopted. At this time, the host material mainly has a function of promoting the recombination of electrons and holes and confining excitons in the light emitting layer, and the dopant material efficiently emits excitons obtained by the recombination. Has a function. In the case of a phosphorescent device, the host material mainly has a function of confining excitons generated by the dopant in the light emitting layer.

The charge transporting thin film of the present invention can be suitably used as a functional layer provided between the anode and the light emitting layer in an organic EL device, and can be used as a hole injection layer, a hole transport layer, or a hole injection transport layer. It can be used more preferably, and can be used even more preferably as a hole injection layer.

The materials and manufacturing methods used when manufacturing an organic EL device using the charge transporting varnish of the present invention include, but are not limited to, the following.

An example of a method for producing an organic EL device having a hole injection layer made of a charge transporting thin film obtained from the charge transporting varnish of the present invention is as follows. It is preferable that the electrodes are preliminarily cleaned with alcohol, pure water, or the like, or surface-treated with UV ozone treatment, oxygen-plasma treatment, or the like, as long as the electrodes are not adversely affected.

A hole injection layer is formed on the anode substrate by the above method using the charge transporting varnish of the present invention. This is introduced into a vacuum vapor deposition apparatus, and a hole transport layer, a light emitting layer, an electron transport layer / hole block layer, an electron injection layer, and a cathode metal are sequentially vapor-deposited. Alternatively, instead of forming the hole transport layer and the light emitting layer by vapor deposition in the method, a composition for forming a hole transport layer containing a hole transport polymer and a composition for forming a light emitting layer containing a light emitting polymer are used. These layers are formed by a wet process using. If necessary, an electron block layer may be provided between the light emitting layer and the hole transport layer.

Examples of the anode material include transparent electrodes typified by indium tin oxide (ITO) and indium zinc oxide (IZO), metals typified by aluminum, and metal anodes composed of alloys thereof. , A flattened product is preferable. Polythiophene derivatives and polyaniline derivatives having high charge transport properties can also be used. Examples of other metals constituting the metal anode include, but are not limited to, gold, silver, copper, indium, and alloys thereof.

Examples of the material for forming the hole transport layer include (triphenylamine) dimer derivative, [(triphenylamine) dimer] spirodimer, and N, N'-bis (naphthalen-1-yl) -N, N'-. Bis (phenyl) -benzidine (α-NPD), 4,4', 4''-tris [3-methylphenyl (phenyl) amino] triphenylamine (m-MTDATA), 4,4', 4''- Triarylamines such as tris [1-naphthyl (phenyl) amino] triphenylamine (1-TNATA), 5,5''-bis- {4- [bis (4-methylphenyl) amino] phenyl} -2 , 2': 5', 2''-oligothiophenes such as turthiophene (BMA-3T) and the like can be mentioned.

Examples of the material forming the light emitting layer include a metal complex such as an aluminum complex of 8-hydroxyquinoline, a metal complex of 10-hydroxybenzo [h] quinoline, a bisstyrylbenzene derivative, a bisstyryl arylene derivative, and (2-hydroxyphenyl). Low molecular weight luminescent materials such as benzothiazole metal complexes and silol derivatives; poly (p-phenylene vinylene), poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene], poly (3- Alkylthiophene), a system in which a light emitting material and an electron transfer material are mixed with a polymer compound such as polyvinylcarbazole, and the like, but are not limited thereto.

When the light emitting layer is formed by vapor deposition, it may be co-deposited with a light emitting dopant, and the light emitting dopant may be a metal such as tris (2-phenylpyridine) iridium (III) (Ir (ppy) ₃ ). Examples thereof include, but are not limited to, a complex, a naphthacene derivative such as rubrene, a quinacridone derivative, and a condensed polycyclic aromatic ring such as perylene.

Examples of the material for forming the electron transport layer / whole block layer include, but are not limited to, an oxydiazole derivative, a triazole derivative, a phenanthroline derivative, a phenylquinoxaline derivative, a benzimidazole derivative, and a pyrimidine derivative.

Examples of the material forming the electron injection layer include metal oxides such as lithium oxide (Li ₂ O), magnesium oxide (Mg O), and alumina (Al ₂ O ₃ ), lithium fluoride (LiF), and sodium fluoride (NaF). ), But is not limited to these.

Examples of the cathode material include, but are not limited to, aluminum, magnesium-silver alloy, aluminum-lithium alloy, and the like.

Examples of the material for forming the electron block layer include, but are not limited to, tris (phenylpyrazole) iridium and the like.

Examples of the hole-transporting polymer include poly [(9,9-dihexylfluorenyl-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1,4-diamino). Phenylene)], 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)], poly [N, N'-bis (4-butylphenyl) -N, N'-bis (phenyl) -benzidine] -endcapped with polysilsesquioxane, poly [(9,, 9-didioctylfluorenyl-2,7-diyl) -co- (4,4'-(N- (p-butylphenyl)) diphenylamine)] and the like can be mentioned.

Examples of the luminescent polymer include polyfluorene derivatives such as poly (9,9-dialkylfluorene) (PDAF) and poly (2-methoxy-5- (2'-ethylhexoxy) -1,4-phenylene vinylene) (MEH). -PPV) and other polyphenylene vinylene derivatives, poly (3-alkylthiophene) (PAT) and other polythiophene derivatives, polyvinylcarbazole (PVCz) and the like can be mentioned.

The anode, cathode, and the material forming the layer formed between them differ depending on whether the element having the bottom emission structure or the top emission structure is manufactured. Therefore, the material is appropriately selected in consideration of this point. ..

Normally, in an element having a bottom emission structure, a transparent anode is used on the substrate side and light is extracted from the substrate side, whereas in an element having a top emission structure, a reflective anode made of metal is used and the direction is opposite to that of the substrate. Light is extracted from a certain transparent electrode (cathode) side. Therefore, for example, regarding the anode material, a transparent anode such as ITO is used when manufacturing an element having a bottom emission structure, and a reflective anode such as Al / Nd is used when manufacturing an element having a top emission structure.

The organic EL device of the present invention may be sealed together with a water catching agent or the like, if necessary, in accordance with a conventional method in order to prevent deterioration of characteristics.

As described above, the charge transporting varnish of the present invention is suitably used for forming a functional layer of an organic EL element, but in addition, an organic photoelectric conversion element, an organic thin film solar cell, an organic perovskite photoelectric conversion element, and an organic integrated circuit , Organic field effect transistor, organic thin film, organic light emitting transistor, organic optical tester, organic photoreceiver, organic electric field extinguishing element, light emitting electronic chemical battery, quantum dot light emitting diode, quantum laser, organic laser diode and organic Plasmon light emitting device It can also be used to form a functional layer in an electronic device such as.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. The devices used are as follows.
(1) ¹ H-NMR: Nuclear magnetic resonance spectrometer AVANCE III HD 500MHz manufactured by Bruker Biospin Co., Ltd.
(2) Substrate cleaning: Substrate cleaning equipment manufactured by Choshu Sangyo Co., Ltd. (decompression plasma method)
(3) Varnish application: Spin coater MS-A100 manufactured by Mikasa Co., Ltd.
(4) Film thickness measurement: Fine shape measuring machine surf coder ET-4000 manufactured by Kosaka Laboratory Co., Ltd.
(5) Manufacture of EL element: Multi-function vapor deposition equipment system C-E2L1G1-N manufactured by Choshu Sangyo Co., Ltd.
(6) Measurement of brightness, etc. of EL element: Multi-channel IVL measuring device manufactured by EHC Co., Ltd. (7) Life measurement of EL element (luminance half-life measurement): Organic EL brightness manufactured by EHC Co., Ltd. Life evaluation system PEL-105S
(8) Measurement of refractive index and extinction coefficient: J.A. Woolam Japan, multi-entry angle spectroscopic ellipsometer VASE

[1] Synthesis of compound [Synthesis example 1] Synthesis of intermediate A

Synthesis was carried out according to the method described in J. Mater. Chem. C, 2014, pp. 1068-1075, and Intermediate A (2,7-dibromo-9,9-bis (4-nitrophenyl) -9H-fluorene ) Was obtained.

[Example 1-1] Synthesis of fluorene derivative A [Example 1-1-1] Synthesis of intermediate B

Synthesis was carried out according to the method described in WO 2017/122649, and Intermediate B (4,4'-(9,9-bis (4-nitrophenyl) -9H-fluorene-2,7-diyl) bis ( N, N-diphenylaniline)) was obtained.

[Example 1-1-2] Synthesis of Intermediate C

Synthesis was carried out according to the method described in WO 2017/122649, and intermediate C (4,4'-(9,9-bis (4-aminophenyl) -9H-fluorene-2,7-diyl) bis ( N, N-diphenylamine)) was obtained.

[Example 1-1-3] Synthesis of fluorene derivative A

Intermediate C (1 g, 1.2 mmol), THF (2 mL) and trimethylamine (368 μL, 2.64 mmol) were placed in a reaction vessel to carry out nitrogen substitution, and then 1-naphthoyl chloride (1-naphthoyl chloride) (cooled in an ice bath). 396 μL (2.6 mmol) was added dropwise. After completion of the dropping, the mixture was stirred at room temperature for 1 hour. Ion-exchanged water (25 mL) was added to the reaction mixture, and the mixture was extracted with ethyl acetate (25 mL). The extraction operation was performed three times. After drying the organic layer with anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure. The concentrate was added dropwise to 2-propanol (20 mL) and the suspension was stirred at room temperature. Filter, dry the filter, and obtain the desired fluorene derivative A (N, N'-(2,7-bis (4- (diphenylamino) phenyl-9H-fluorene-9,9-diyl) bis (4). , 1-Phenylene)) bis (1-naphthamide)) was obtained in an amount of 1.16 g (yield: 85%). The measurement results of ¹ H-NMR are shown below.
^{1 1} H-NMR (500MHz, DMSO-d6) δ [ppm]: 7.05-7.07 (m, 16H), 7.26-7.33 (m, 12H), 7.56-7.60 (m, 10H), 7.62-7.74 (m, 10H) ), 7.99-8.06 (m, 6H), 8.13-8.15 (m, 2H), 10.58 (brs, 2H).

[Example 1-2] Synthesis of fluorene derivative B The purpose is the same as in Example 1-1-3, except that benzoyl chloride (304 μL, 2.64 mmol) is used instead of 1-naphthoyl chloride. 1.07 g of fluorene derivative B (N, N'-(2,7-bis (4- (diphenylamino) phenyl-9H-fluorene-9,9-diyl) bis (4,1-phenylene)) bisbenzamide) Obtained (yield: 85%). The measurement results of ¹ H-NMR are shown below.
^{1 1} H-NMR (500MHz, DMSO-d6) δ [ppm]: 7.03-7.07 (m, 16H), 7.24 (d, J = 8.5Hz, 4H), 7.29-7.33 (m, 8H), 7.49-7.52 ( m, 4H), 7.55-7.61 (m, 6H), 7.69-7.73 (m, 8H), 7.90 (dd, J = 1.5Hz, 8.5Hz, 4H), 8.20 (d, J = 7.5Hz, 2H), 10.24 (brs, 2H).

[Example 1-3] Synthesis of fluorene derivative C [Example 1-3-1] Synthesis of intermediate D

Synthesis was carried out according to the method described in WO 2017/122649, and Intermediate D (3,3'-(9,9-bis (4-nitrophenyl) -9H-fluorene-2,7-diyl) bis ( 9-Phenyl-9H-carbazole)) was obtained.

[Example 1-3-2] Synthesis of intermediate E

Synthesis was carried out according to the method described in WO 2017/122649, and Intermediate E (4,4'-(2,7-bis (9-phenyl-9H-carbazole-3-yl) -9H-fluorene-9) was carried out. , 9-jiyl) dianiline) was obtained.

[Example 1-3-3] Synthesis of fluorene derivative C

The target fluorene derivative C (N, N'-(((N, N'-(() is the same as in Example 1-1-3, except that Intermediate E (1.13 g, 1.36 mmol) is used instead of Intermediate C. Obtained 1.46 g of 2,7-bis (9-phenyl-9H-carbazole-3-yl) -9H-fluorene-9,9-diyl) bis (4,1-phenylene)) bis (1-naphthamide). (Yield: 94%). The measurement results of ¹ H-NMR are shown below.
^{1 1} H-NMR (500MHz, DMSO-d6) δ [ppm]: 7.32 (t, J = 7.0Hz, 2H), 7.39-7.41 (m, 6H), 7.46 (t, J = 7.5Hz, 4H), 7.54 -7.58 (m, 8H), 7.65-7.72 (m, 10H), 7.78-7.80 (m, 6H), 7.91-7.99 (m, 6H), 8.04 (d, J = 8.5Hz, 2H), 8.12-8.15 (m, 4H), 8.41 (d, J = 8.0Hz, 2H), 8.65 (s, 2H), 10.59 (brs, 2H).

[Example 1-4] Synthesis of fluorene derivative D [Example 1-4-1] Synthesis of intermediate F

In the reaction vessel, intermediate A (0.57 g, 1 mmol), 9-phenylcarbazole-2-boronic acid (0.63 g, 2.2 mmol), potassium carbonate (0.55 g, 4 mmol), 1,4-dioxane ( 11 mL), ion-exchanged water (2.8 mL) and Pd (PPh ₃ ) ₄ (57.8 mg, 0.05 mmol) were added, and after nitrogen substitution, the mixture was stirred at 90 ° C. for 3 hours. After cooling to room temperature, ion-exchanged water (8.4 mL) was added to the reaction mixture, filtration was performed, and the filtrate was washed with ion-exchanged water (11 mL). Washing was performed twice. 1,4-Dioxane (5.6 g) was added to the filter, and the mixture was stirred at 90 ° C. for 1 hour. After cooling to room temperature, filtration is performed, the filtrate is washed with 1,4-dioxane (5.6 g), and the target intermediate F (2,2'-(9,9-bis (4-nitrophenyl)) is used. ) -9H-Fluorene-2,7-diyl) bis (9-phenyl-9H-carbazole)) was obtained in an amount of 0.68 g (yield: 76%).

[Example 1-4-2] Synthesis of intermediate G

Intermediate F (3 g, 3.3 mmol), DMF (60 mL) and 5% Pd / C (0.3 g) were placed in a reaction vessel, hydrogen substituted, and then stirred at room temperature for 48 hours. After nitrogen substitution, it was filtered through Celite and washed with DMF (30 mL). The filtrate was evaporated under reduced pressure, the concentrate was added dropwise to ethyl acetate (20 mL), and the suspension was stirred at room temperature. Filter and dry the filter to obtain the desired intermediate G (4,4'-(2,7-bis (9-phenyl-9H-carbazole-2-yl) -9H-fluorene-9,9-). 2.10 g of diyl) dianiline) was obtained (yield: 77%).

[Example 1-4-3] Synthesis of fluorene derivative D

Example 1-1-except that Intermediate G (0.9 g, 1.08 mmol) was used in place of Intermediate A and Benzoyl chloride (274 μL, 2.38 mmol) was used in place of 1-naphthoyl chloride. The target fluorene derivative D (N, N'-((2,7-bis (9-phenyl-9H-carbazole-2-yl) -9H-fluorene-9,9-diyl) bis) in the same manner as in 3. (4,1-phenylene)) bisbenzamide) was obtained in an amount of 0.86 g (yield: 69%). The measurement results of ¹ H-NMR are shown below.
¹ H-NMR (500MHz, DMSO-d6) δ [ppm]: 7.26-7.32 (m, 6H), 7.40-7.42 (m, 4H), 7.43-7.59 (m, 12H), 7.68-7.77 (m, 16H) ), 7.93-7.94 (m, 4H), 8.04 (d, J = 7.5Hz, 2H), 8.27 (d, J = 7.5Hz, 2H), 8.32 (d, J = 8.0Hz, 2H), 10.26 (brs) , 2H).

[Example 1-5] Synthesis of fluorene derivative E

The target fluorene derivative E (N, N'-) was used in the same manner as in Example 1-1-3, except that 2-tenoyl chloride (280 μL, 2.64 mmol) was used instead of 1-naphthoyl chloride. 1.02 g of (2,7-bis (4- (diphenylamino) phenyl-9H-fluorene-9,9-diyl) bis (4,1-phenylene)) bis (thiophene-2-carboxamide)) was obtained ( Yield: 80%). The measurement results of ¹ H-NMR are shown below.
¹ H-NMR (500MHz, DMSO-d6) δ [ppm]: 7.02-7.07 (m, 16H), 7.20 (dd, J = 4Hz, 4.5Hz, 2H), 7.23 (d, J = 9.0Hz, 4H) , 7.30-7.33 (m, 8H), 7.60 (d, J = 8.5Hz, 4H), 7.64 (d, J = 8.5Hz, 4H), 7.69 (s, 2H), 7.72 (d, J = 8.0Hz, 2H), 7.83 (d, J = 5.0Hz, 2H), 7.97 (d, J = 3.5Hz, 2H), 8.01 (d, J = 8.5Hz, 2H), 10.21 (brs, 2H).

[Example 1-6] Synthesis of fluorene derivative F

The fluorene derivative F of interest was prepared in the same manner as in Example 1-1-3, except that benzo [b] thiophene-2-carbonyl chloride (517 mg, 2.64 mmol) was used instead of 1-naphthoyl chloride. N, N'-(2,7-bis (4- (diphenylamino) phenyl-9H-fluorene-9,9-diyl) bis (4,1-phenylene)) bis (benzo [b] thiophene-2-carboxamide) )) Was obtained (yield: 83%). The measurement results of ¹ H-NMR are shown below.
¹ H-NMR (500MHz, DMSO-d6) δ [ppm]: 7.03-7.07 (m, 16H), 7.26-7.33 (m, 12H), 7.44-7.50 (m, 4H), 7.61 (d, J = 8.5) Hz, 4H), 7.69-7.74 (m, 8H), 7.99 (d, J = 7.5Hz, 2H), 8.03 (dd, J = 6.5Hz, 8.0Hz, 4H), 8.32 (s, 2H), 10.51 ( brs, 2H).

[2] Preparation of charge-transporting varnish [Example 2-1] Preparation of charge-transporting varnish A1 It is represented by the following formula synthesized with fluorene derivative A (174 mg) according to the method described in International Publication No. 2017/217455. Arylsulfonic acid ester A (0.189 g) was dissolved in a mixed solvent of triethylene glycol butyl methyl ether (2 g), butyl benzoate (4 g) and dimethyl phthalate (4 g) with stirring at room temperature. The obtained solution was filtered using a filter made of polytetrafluoroethylene (PTFE) having a pore size of 0.2 μm to obtain a charge-transporting varnish A1.

[Example 2-2] Preparation of charge-transporting varnish B1 Fluolene derivative B (165 mg) and aryl sulfonic acid ester A (0.198 g) were mixed with triethylene glycol butyl methyl ether (2 g) and butyl benzoate (4 g). And dimethyl phthalate (4 g) were dissolved in a mixed solvent at room temperature with stirring. The obtained solution was filtered using a PTFE filter having a pore size of 0.2 μm to obtain a charge-transporting varnish B1.

[Example 2-3] Preparation of charge-transporting varnish C1 Fluolene derivative C (173 mg) and aryl sulfonic acid ester A (0.190 g) were mixed with triethylene glycol butyl methyl ether (2 g) and butyl benzoate (4 g). And dimethyl phthalate (4 g) were dissolved in a mixed solvent at room temperature with stirring. The obtained solution was filtered using a PTFE filter having a pore size of 0.2 μm to obtain a charge-transporting varnish C1.

[Example 2-4] Preparation of charge-transporting varnish D1 Fluolene derivative D (165 mg) and aryl sulfonic acid ester A (0.198 g) were mixed with triethylene glycol butyl methyl ether (2 g) and butyl benzoate (4 g). And dimethyl phthalate (4 g) were dissolved in a mixed solvent at room temperature with stirring. The obtained solution was filtered using a PTFE filter having a pore size of 0.2 μm to obtain a charge-transporting varnish D1.

[Example 2-5] Preparation of charge-transporting varnish E1 Fluolene derivative E (166 mg) and aryl sulfonic acid ester A (0.197 g) were mixed with triethylene glycol butyl methyl ether (2 g) and butyl benzoate (4 g). And dimethyl phthalate (4 g) were dissolved in a mixed solvent at room temperature with stirring. The obtained solution was filtered using a PTFE filter having a pore size of 0.2 μm to obtain a charge-transporting varnish E1.

[Example 2-6] Preparation of charge-transporting varnish F1 Fluolene derivative F (175 mg) and aryl sulfonic acid ester A (0.188 g) were mixed with triethylene glycol butyl methyl ether (2 g) and butyl benzoate (4 g). And dimethyl phthalate (4 g) were dissolved in a mixed solvent at room temperature with stirring. The obtained solution was filtered using a PTFE filter having a pore size of 0.2 μm to obtain a charge-transporting varnish F1.

[Example 2-7] Preparation of charge-transporting varnish A2 Fluorene derivative A (363 mg) is mixed with triethylene glycol butylmethyl ether (2 g), butyl benzoate (4 g) and dimethyl phthalate (4 g) at room temperature. It was stirred and dissolved. The obtained solution was filtered using a PTFE filter having a pore size of 0.2 μm to obtain a charge-transporting varnish A2.

[Examples 2-8 to 2-12] Preparation of charge-transporting varnishes B2, C2, E2 and F2 Examples 2-7 except that the fluorene derivative A was changed to the fluorene derivatives B, C, E and F, respectively. Charge-transporting varnishes B2, C2, E2 and F2 were obtained in the same manner as in the above.

[3] Evaluation of Refractive Index (n) and Extinction Coefficient (k) [Examples 3-1 to 3-5]
Charge-transporting varnishes A1, B1, C1, E1 and F1 are each applied to a quartz substrate using a spin coater, and then calcined at 120 ° C. for 1 minute in an air atmosphere, and then 15 at 200 ° C. This firing was carried out for a minute to form a uniform thin film of 50 nm on a quartz substrate.
Using the obtained quartz substrate with a film, the visible region average refractive index n and the visible region average extinction coefficient k at a wavelength of 400 to 800 nm were measured. The results are shown in Table 1.

As shown in Table 1, the charge-transporting thin film of the present invention had a high refractive index of 1.65 or more and a low extinction coefficient of 0.03 or less.

[4] Fabrication and characterization of hole-only elements (HOD) -1
In the following examples, the ITO substrate is a 25 mm × 25 mm × 0.7 t glass substrate in which ITO is patterned on the surface with a film thickness of 150 nm, and is an O ₂ plasma cleaning device (150 W, 30 seconds) before use. ) Was used to remove impurities on the surface.

[Preparation of hole injection layer solution]
It is represented by 0.137 g of an aniline derivative represented by the following formula (S1) synthesized according to the method described in WO2013 / 084664 and the formula (S2) synthesized according to the method described in WO 2006/025432. 0.271 g of aryl sulfonic acid was dissolved in 6.7 g of 1,3-dimethyl-2-imidazolidinone under a nitrogen atmosphere. To the obtained solution, 10 g of cyclohexanol and 3.3 g of propylene glycol were sequentially added and stirred to prepare a hole injection layer solution.

[Example 4-1]
The hole injection layer solution was applied onto an ITO substrate using a spin coater, then provisionally fired on a hot plate at 80 ° C. for 1 minute in an air atmosphere, and then main fired at 230 ° C. for 15 minutes. A hole injection layer (thickness 30 nm) was formed. Next, the charge-transporting varnish A2 was applied onto the hole injection layer using a spin coater, the solvent was removed by vacuum drying at room temperature, and the mixture was fired at 130 ° C. for 10 minutes in an air atmosphere to have a film thickness of 40 nm. Hole transport layer was formed. On this, an aluminum thin film of 80 nm was formed at 0.2 nm / sec using a vapor deposition apparatus (vacuum degree 1.0 × 10 ^-5 Pa) to prepare a hole-only element (HOD).

[Examples 4-2 to 4-5]
HOD was prepared in the same manner as in Example 4-1 except that the charge-transporting varnish A2 was replaced with the charge-transporting varnish B2, C2, E2 or F2.

For each HOD produced in Examples 4-1 to 4-5, the current density at a drive voltage of 4 V was measured. The results are shown in Table 2.

As shown in Table 2, the thin film prepared from the charge-transporting varnish of the present invention showed good charge-transporting properties.

[5] Fabrication of Single-Layer Element (SLD) [Example 5-1]
After applying the charge-transporting varnish A1 on the ITO substrate using a spin coater, it is tentatively fired at 120 ° C. for 1 minute in an air atmosphere, and then main fired at 200 ° C. for 15 minutes to form a hole injection layer ( A film thickness of 50 nm) was formed. On this, an aluminum thin film having a film thickness of 80 nm was formed at 0.2 nm / sec using a vapor deposition apparatus (vacuum degree 1.0 × 10 ^-5 Pa) to prepare a single-layer element (SLD).

[Examples 5-2 to 5-6]
An SLD was prepared in the same manner as in Example 5-1 except that the charge-transporting varnishes B1, C1, D1, E1 or F1 were used instead of the charge-transporting varnish A1.

For each SLD prepared in Examples 5-1 to 5-6, the current density at a drive voltage of 4 V was measured. The results are shown in Table 3.

As shown in Table 3, the thin film prepared from the charge-transporting varnish of the present invention showed good charge-transporting properties.

[6] Preparation of HOD and its evaluation-2
[Example 6-1]
After applying the charge-transporting varnish A1 to the ITO substrate using a spin coater, it is tentatively fired at 120 ° C. for 1 minute in an air atmosphere, then main fired at 200 ° C. for 15 minutes, and then fired on the ITO substrate at 50 nm. A thin film was formed. On top of this, a thin film of α-NPD and aluminum was sequentially laminated using a vapor deposition apparatus (vacuum degree 2.0 × 10 ^-5 Pa) to prepare a HOD. The vapor deposition was carried out under the condition of a vapor deposition rate of 0.2 nm / sec. The film thicknesses of the α-NPD and aluminum thin films were 30 nm and 80 nm, respectively.

[Examples 6-2 to 6-5]
HOD was prepared in the same manner as in Example 6-1 except that the charge-transporting varnishes B1, C1, E1 or F1 were used instead of the charge-transporting varnish A1.

The current densities of the HODs produced in Examples 6-1 to 6-5 at a drive voltage of 4 V were measured. The results are shown in Table 4.

As shown in Table 4, the thin film prepared from the charge-transporting varnish of the present invention showed good charge-transporting property.

[7] Fabrication of organic EL device and evaluation of characteristics [Example 7-1]
After applying the charge-transporting varnish A1 to the ITO substrate using a spin coater, it is tentatively fired at 120 ° C. for 1 minute in an air atmosphere, then main fired at 200 ° C. for 15 minutes, and then fired on the ITO substrate at 50 nm. A thin film was formed.
Next, α-NPD was formed on the ITO substrate on which the thin film was formed at 0.2 nm / sec using a vapor deposition apparatus (vacuum degree 1.0 × 10 ^-5 Pa) at 30 nm. Next, a 10 nm film was formed on the electronic block material HTEB-01 manufactured by Kanto Chemical Co., Inc. Next, the light emitting layer host material NS60 and the light emitting layer dopant material Ir (ppy) ₃ manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. were co-deposited. For co-evaporation, the vapor deposition rate was controlled so that the concentration of Ir (ppy) ₃ was 6%, and 40 nm was laminated. Next, a thin film of Alq ₃ , lithium fluoride, and aluminum was sequentially laminated to prepare an organic EL device. At this time, the vapor deposition rate was 0.2 nm / sec for Alq ₃ 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 the characteristics due to the influence of oxygen, water, etc. in the air, the organic EL element was sealed with a sealing substrate and then the characteristics were evaluated. Sealing was performed by 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 is placed between the sealing substrates, and the sealing substrate is an adhesive (Matsumura Oil Research Corp., Moresco Moisture Cut WB90US (P)). It was pasted together. At this time, a water trapping agent (HD-071010W-40 manufactured by Dynic Co., Ltd.) was housed in the sealing substrate together with the organic EL element. The bonded substrate was irradiated with UV light (wavelength: 365 nm, irradiation amount: 6,000 mJ / cm ² ), and then annealed at 80 ° C. for 1 hour to cure the adhesive.

[Examples 7-2 to 7-5]
An organic EL device was produced in the same manner as in Example 7-1 except that the charge-transporting varnishes B1, C1, E1 or F1 were used instead of the charge-transporting varnish A1.

The drive voltage, current density, current efficiency, luminous efficiency, external emission quantum yield (EQE), and LT90 (initial brightness 5,000 cd /) when the obtained organic EL element is made to emit light at 5,000 cd / m ^2. The time required for a 10% reduction in m ² ) was measured. The results are shown in Table 5.

As shown in Table 5, all of the organic EL devices of the present invention showed high current efficiency and high EQE, and also showed good life characteristics.

Claims

A fluorene derivative represented by the following formula (1).

[In the formula, Z 1 and Z 2 are groups represented by any of the following formulas (2) to (7) independently;

(Wherein, a broken line is a bond .R A and R B are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.)
Ar 1 and Ar 2 are independently an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, and are a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, and 1 carbon atom. Alkyl group of ~ 20, cycloalkyl group of 3 to 20 carbons, bicycloalkyl group of 4 to 20 carbons, alkoxy group of 2 to 20 carbons, alkynyl group of 2 to 20 carbons or alkynyl group of 1 to 20 carbons May be substituted with an alkoxy group;
Ar 3 and Ar 4 are groups represented by any of the following formulas (8) to (11) independently.

(In the formula, the broken line is the join hand,
R 1 is substituted with a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkyl halide group having 1 to 20 carbon atoms. A heteroaryl group having 6 to 20 carbon atoms, or a heteroaryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group having 1 to 20 carbon atoms or an alkyl halide group having 1 to 20 carbon atoms, or the following. A group represented by any of the formulas (12) to (14).
R 2 to R 52 are independently hydrogen atoms, cyano groups, nitro groups, halogen atoms, alkyl groups having 1 to 20 carbon atoms, or alkyl halide groups having 1 to 20 carbon atoms.

(In the formula, the broken line is the join hand,
D A is a diarylamino group each aryl group is independently C 6 -C 20 -aryl group,
R 53 to R 76 are independently hydrogen atoms, cyano groups, nitro groups, halogen atoms, alkyl groups having 1 to 20 carbon atoms, or alkyl halide groups having 1 to 20 carbon atoms. ))]
Ar 1 and Ar 2 are independently phenyl group, 1-naphthyl group or 2-naphthyl group, or the following formulas (T1-1) to (T11-4), formulas (F1-1) to (F4-4). ), The fluorene derivative according to claim 1, which is a group represented by the formulas (N1-1) to (N10-7) or the formulas (M1-1) to (M4-3).

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)

(In the formula, the broken line is the joiner.)
The fluorene derivative according to claim 1 or 2, wherein Ar 1 and Ar 2 are the same group.
The fluorene derivative according to any one of claims 1 to 3, wherein Z 1 and Z 2 are groups represented by the formula (2).
The fluorene derivative according to any one of claims 1 to 4, wherein R 1 is a phenyl group.
The fluorene derivative according to any one of claims 1 to 5, wherein R 2 to R 76 are hydrogen atoms.
A charge-transporting substance composed of the fluorene derivative according to any one of claims 1 to 6.
A charge-transporting varnish containing the charge-transporting substance and an organic solvent according to claim 7.
The charge transporting varnish according to claim 8, further comprising a dopant.
A charge-transporting thin film obtained from the charge-transporting varnish according to claim 8 or 9.
The organic electroluminescence device including the charge transporting thin film according to claim 10.
The compound represented by the formula (15) is reacted with the compound represented by the formula (16-1) and the compound represented by the formula (16-2) to obtain an intermediate represented by the formula (17). Process,
The step of reducing the intermediate represented by the formula (17) to obtain the intermediate represented by the formula (18), and the intermediate represented by the formula (18) and the intermediate represented by the formula (19-1). A method for producing a fluorene derivative represented by the following formula (1), which comprises a step of reacting a halide with a halide represented by the formula (19-2).

[In the formula, Z 1 and Z 2 are groups represented by any of the following formulas (2) to (7) independently;

(Wherein, a broken line is a bond .R A and R B are each independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.)
Ar 1 and Ar 2 are independently an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, and are a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, and 1 carbon atom. Alkyl group of ~ 20, cycloalkyl group of 3 to 20 carbons, bicycloalkyl group of 4 to 20 carbons, alkoxy group of 2 to 20 carbons, alkynyl group of 2 to 20 carbons or alkynyl group of 1 to 20 carbons May be substituted with an alkoxy group;
Ar 3 and Ar 4 are independently represented by any of the following formulas (8) to (11);

(In the formula, the broken line is the join hand,
R 1 is substituted with a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkyl halide group having 1 to 20 carbon atoms. A heteroaryl group having 6 to 20 carbon atoms, or a heteroaryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group having 1 to 20 carbon atoms or an alkyl halide group having 1 to 20 carbon atoms, or the following. A group represented by any of the formulas (12) to (14).
R 2 to R 52 are independently hydrogen atoms, cyano groups, nitro groups, halogen atoms, alkyl groups having 1 to 20 carbon atoms, or alkyl halide groups having 1 to 20 carbon atoms.

(In the formula, the broken line is the join hand,
D A is a diarylamino group each aryl group is independently C 6 -C 20 -aryl group,
R 53 to R 76 are independently hydrogen atoms, cyano groups, nitro groups, halogen atoms, alkyl groups having 1 to 20 carbon atoms, or alkyl halide groups having 1 to 20 carbon atoms. )))
X is a halogen atom or a pseudohalogen group. ]