JP2021127325A - Aromatic diamine derivative - Google Patents

Abstract

To provide an aromatic diamine derivative that makes it possible to prepare a blue organic electroluminescent element having high luminous efficiency and sufficient service life.SOLUTION: An aromatic diamine derivative is represented by the formula (1) [in the formula (1), the meanings of R1, R2, Am1, Am2 and Y are each defined in the specifications].SELECTED DRAWING: Figure 1

Description

The present invention relates to aromatic diamine derivatives.

In recent years, as a thin film type electroluminescent device, an organic electroluminescent device using an organic thin film has been developed instead of one using an inorganic material. An organic electroluminescent device (OLED) usually has a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and the like between an anode and a cathode. Materials suitable for each of these layers are being developed, and the emission colors are red, green, and blue, respectively.

However, as compared with the red light emitting element and the green light emitting element, the blue light emitting element has not been realized to be satisfactory in terms of efficiency and life, and further higher efficiency and longer life are desired.

For example, as a light emitting material used for a blue light emitting device, Patent Document 1 includes a compound represented by the following formula (A) (compound (A)) and a compound represented by the following formula (B) (compound (B)). It is disclosed.

Special Table 2009-542735

However, the compound (A) disclosed in Patent Document 1 has a problem that the emission wavelength is shortened and the luminous efficiency of the device is lowered. Further, although the compound (B) emits blue light, the efficiency of the device is not sufficiently high, and there is room for improvement in the drive life.

An object of the present invention is to provide a compound capable of producing a blue organic electroluminescent element having high luminous efficiency and a sufficient life.

As a result of diligent studies by the present inventors, it was found that the above problems can be solved by using, for example, a compound represented by the following formula (1), and the present invention has been reached. That is, the present invention relates to the following <1> to <7>.

<1> An aromatic diamine derivative represented by the following formula (1).

[In formula (1), R ¹ and R ² each independently consist of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group consisting of an aromatic hydrocarbon group and an aromatic heterocyclic group. A group in which a plurality of selected at least one group is linked directly or via a linking group. R ¹ and R ² may be combined with each other to form a ring. R ¹ and R ² may have a substituent. Am ¹ is a substituent represented by the following general formula (2a). Am ² is a substituent represented by the following general formula (2b). Y is a heteroatom.

In the formulas (2a) and (2b), the asterics (*) represent the combination with the formula (1). Ar ^{1 to} Ar ⁴ are independently directly derived from at least one group selected from the group consisting of an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Alternatively, it is a group in which a plurality of groups are linked via a linking group. Ar ¹ and Ar ² may be combined with each other to form a ring. Ar ³ and Ar ⁴ may be combined with each other to form a ring. Ar ^{1 to} Ar ⁴ may have a substituent. ]
<2> The aromatic diamine derivative according to <1>, wherein the formula (1) is the following formula (3).

[In the formula (3), R ¹ , R ² , Am ¹ and Am ² are the same as those in the formula (1). ]
<3> The aromatic diamine derivative according to <1> or <2>, ^{wherein Ar 2 is a substituent represented by the following formula (4a).}

[In the formula (4a), the asterics (*) represent the bond with the nitrogen atom in the formula (2a), and X ₁ is an oxygen atom, a sulfur atom, N-R ⁴¹ , or C (R ⁵¹ ) (R). ⁶¹ ) is represented. In R ³¹ , at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group has a direct or linking group. Represents a plurality of groups linked via a group. R ⁴¹ , R ⁵¹ , and R ⁶¹ are independently selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Represents a group in which a plurality of at least one group to be linked is directly or via a linking group. n represents an integer from 0 to 7. R ³¹ , R ⁴¹ , R ⁵¹ , and R ⁶¹ may have a substituent. ]
<4> The aromatic diamine derivative according to any one of <1> to <3>, ^{wherein Ar 4 is a substituent represented by the following formula (4b).}

[In the formula (4b), the asterix (*) represents the bond with the nitrogen atom in the formula (2b), and X ₂ is an oxygen atom, a sulfur atom, N-R ⁴² , or C (R ⁵² ) (R). ⁶² ). In R ³² , at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group has a direct or linking group. Represents a plurality of groups linked via a group. R ⁴² , R ⁵² , and R ⁶² are independently selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Represents a group in which a plurality of at least one group to be linked is directly or via a linking group. m represents an integer from 0 to 7. R ³² , R ⁴² , R ⁵² , and R ⁶² may have a substituent. ]
<5> A light emitting material for an organic electroluminescent device containing the aromatic diamine derivative according to any one of <1> to <4>.
<6> A composition for an OLED containing two or more kinds of a light emitting material for an organic electric field light emitting device according to <5> and a solvent having a boiling point of 150 ° C. or higher.
<7> An organic electroluminescent device including the light emitting material for the organic electroluminescent device according to <5>.

According to the light emitting material for an organic electroluminescent element having the compound of the present invention (the compound represented by the above formula (1)), it is possible to provide a blue organic electroluminescent element having high luminous efficiency and a sufficient life. ..

It is the schematic of the cross section which shows the structural example of the blue organic electroluminescent element of this invention.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist thereof.

In the present invention, when the term is simply referred to as a "heterocycle" or a "hydrocarbon ring", it shall include both an aromatic ring and a non-aromatic ring.
In the present invention, when simply referred to as an "aromatic ring", it shall include both a hydrocarbon aromatic ring and a heteroaromatic ring.
In the present invention, "may have a substituent" means that it may have one or more substituents.

[Aromatic diamine derivative]
The compound of the present invention is an aromatic diamine derivative represented by the following formula (1).

[In formula (1), R ¹ and R ² each independently consist of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group consisting of an aromatic hydrocarbon group and an aromatic heterocyclic group. A group in which a plurality of selected at least one group is linked directly or via a linking group. R ¹ and R ² may be combined with each other to form a ring. R ¹ and R ² may have a substituent. Am ¹ is a substituent represented by the following general formula (2a). Am ² is a substituent represented by the following general formula (2b). Y is a heteroatom.

In the formulas (2a) and (2b), the asterics (*) represent the combination with the formula (1). Ar ^{1 to} Ar ⁴ are independently directly derived from at least one group selected from the group consisting of an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Alternatively, it is a group in which a plurality of groups are linked via a linking group. Ar ¹ and Ar ² may be combined with each other to form a ring. Ar ³ and Ar ⁴ may be combined with each other to form a ring. Ar ^{1 to} Ar ⁴ may have a substituent. ]

The compound of the present invention has a benzoindeno-dibenzometalol skeleton. This skeleton is less symmetric than the benzoindeno-fluorene skeleton. It is known that when the symmetry is low, the molecules are less likely to associate with each other and the concentration quenching can be suppressed. However, it was unclear what kind of skeleton was actually used to effectively suppress the concentration quenching. As a result of examining compounds having various skeletons, the present inventions have found that the luminous efficiency of the organic electroluminescent element obtained by the compound of the present invention is particularly improved.

Since the compound having a benzofuran dibenzofuran skeleton has high symmetry, it is not expected that the luminous efficiency of the organic electroluminescent element obtained by the compound will be improved.

In addition, since the 9-position of the fluorene skeleton is generally susceptible to decomposition by oxidation, it can be said that the benzoindeno-dibenzometalol skeleton is chemically more stable than the benzoindeno-fluorene skeleton, and the life of the organic electroluminescent element is extended. It is thought that it also contributes to.

<R ¹ , R ² >
R ¹ and R ² are each independently selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. A group in which a plurality of groups are directly linked or linked via a linking group. R ¹ and R ² may be combined with each other to form a ring. R ¹ and R ² may have a substituent.

As the alkyl group, for example, an alkyl group having 10 or less carbon atoms can be used.

Examples of the alkyl group having 10 or less carbon atoms include a methyl group and an ethyl group, a branched, linear or cyclic propyl group, a branched, linear or cyclic butyl group, a branched, a linear or cyclic pentyl group, and a branched group. Examples include linear or cyclic pentyl groups, branched, linear or cyclic hexyl groups, branched, linear or cyclic octyl groups, branched, linear or cyclic nonyl groups, branched, linear or cyclic decyl groups. ..

From the viewpoint of the stability of the compound, a methyl group, an ethyl group, a branched, linear or cyclic propyl group, a branched, linear or cyclic butyl group is preferable, and a methyl group is particularly preferable.

As the aromatic hydrocarbon group, an aromatic hydrocarbon group having 6 or more carbon atoms and 60 or less carbon atoms is preferable, and specifically, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, and a pyrene ring. , Benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluorantene ring, fluorene ring and the like, a 6-membered monocyclic ring or a monovalent group of a 2-5 fused ring can be mentioned.

From the viewpoint of compound stability and solubility, a phenyl group and a naphthyl group are more preferable.

As the aromatic heterocyclic group, an aromatic heterocyclic group having 3 or more carbon atoms and 60 or less carbon atoms is preferable, and specifically, a furan ring, a benzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, Pyrrol ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrrolomidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, flopirol ring, furan ring, thienofuran ring, benzoiso Oxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxalin ring, phenanthridin ring, benzimidazole ring, perimidine ring , A quinazoline ring, a quinazolinone ring, an azulene ring, or the like, a monovalent group of a 5- to 6-membered ring or a 2 to 4 fused ring.

From the viewpoint of compound stability, a dibenzofuranyl group and a dibenzothienyl group are more preferable.

Examples of the group in which a plurality of at least one group selected from the group consisting of an aromatic hydrocarbon group and an aromatic heterocyclic group are directly linked or via a linking group include the above-mentioned aromatic hydrocarbon group and the above-mentioned aromatic. Examples thereof include a group in which at least one group selected from the group consisting of group heterocyclic groups is directly linked or a plurality of groups are linked via a linking group. These may be a group in which a plurality of the same groups are linked, or a group in which a plurality of different groups are linked.

Examples of the group in which a plurality of aromatic hydrocarbon groups are linked to each other include an ortho-biphenyl group, a meta-biphenyl group, a para-biphenyl group, a terphenyl group and the like.

From the viewpoint of the stability and solubility of the compound, an ortho-biphenyl group and a meta-biphenyl group are particularly preferable.

R ¹ and R ² are particularly preferably a methyl group or a phenyl group from the viewpoint of compound stability.

<Y>
Y is a heteroatom.
Examples of the hetero atom include an oxygen atom, a sulfur atom, a selenium atom and the like.
From the viewpoint of compound stability, oxygen atoms and sulfur atoms are preferable, and oxygen atoms are more preferable.

<Ar ^{1 to} Ar ⁴ >
Ar ^{1 to} Ar ⁴ are independently directly derived from at least one group selected from the group consisting of an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Alternatively, it is a group in which a plurality of groups are linked via a linking group. Ar ¹ and Ar ² may be combined with each other to form a ring. Ar ³ and Ar ⁴ may be combined with each other to form a ring. Ar ^{1 to} Ar ⁴ may have a substituent.

A group in which a plurality of at least one group selected from the group consisting of an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group are directly linked or via a linking group. Specific examples and preferable ranges are the same as those described in ^{R 1} and R ^2.

The above formula (1) is preferably the following formula (3) from the viewpoint of compound stability and emission wavelength.

[In the formula (3), R ¹ , R ² , Am ¹ and Am ² are the same as those in the formula (1). ]

Further, Ar ² is preferably a substituent represented by the following formula (4a).

[In the formula (4a), the asterics (*) represent the bond with the nitrogen atom in the formula (2a), and X ₁ is an oxygen atom, a sulfur atom, N-R ⁴¹ , or C (R ⁵¹ ) (R). ⁶¹ ) is represented. In R ³¹ , at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group has a direct or linking group. Represents a plurality of groups linked via a group. R ⁴¹ , R ⁵¹ , and R ⁶¹ are independently selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Represents a group in which a plurality of at least one group to be linked is directly or via a linking group. n represents an integer from 0 to 7. R ³¹ , R ⁴¹ , R ⁵¹ , and R ⁶¹ may have a substituent. ]

When n is 0 in the formula (4a), the substituent represented by the formula (4a) has seven hydrogen atoms.

<X ₁ >
X ₁ represents an oxygen atom, a sulfur atom, N-R ⁴¹ , or C (R ⁵¹ ) (R ⁶¹ ).
From the viewpoint of compound stability, an oxygen atom is particularly preferable.

<R ³¹ , R ⁴¹ , R ⁵¹ , R ⁶¹ >
In R ³¹ , at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group has a direct or linking group. Represents a plurality of groups linked via a group. R ⁴¹ , R ⁵¹ , and R ⁶¹ are independently selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Represents a group in which a plurality of at least one group to be linked is directly or via a linking group.

A plurality of at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, an aromatic hydrocarbon group and an aromatic heterocyclic group are linked directly or via a linking group. Specific examples and preferable ranges of the groups are the same as those described in ^{R 1} and R ^2.

Further, Ar ⁴ is preferably a substituent represented by the following formula (4b).

[In the formula (4b), the asterix (*) represents the bond with the nitrogen atom in the formula (2b), and X ₂ is an oxygen atom, a sulfur atom, N-R ⁴² , or C (R ⁵² ) (R). ⁶² ). In R ³² , at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group has a direct or linking group. Represents a plurality of groups linked via a group. R ⁴² , R ⁵² , and R ⁶² are independently selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Represents a group in which a plurality of at least one group to be linked is directly or via a linking group. m represents an integer from 0 to 7. R ³² , R ⁴² , R ⁵² , and R ⁶² may have a substituent. ]

When m is 0 in the formula (4b), the substituent represented by the formula (4b) has seven hydrogen atoms.

<X ₂ >
X ₂ represents an oxygen atom, a sulfur atom, N-R ⁴² , or C (R ⁵² ) (R ⁶² ).
From the viewpoint of compound stability, an oxygen atom is particularly preferable.

<R ³² , R ⁴² , R ⁵² , R ⁶² >
In R ³² , at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group has a direct or linking group. Represents a plurality of groups linked via a group. R ⁴² , R ⁵² , and R ⁶² are independently selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Represents a group in which a plurality of at least one group to be linked is directly or via a linking group.

A plurality of at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, an aromatic hydrocarbon group and an aromatic heterocyclic group are linked directly or via a linking group. Specific examples and preferable ranges of the groups are the same as those described in ^{R 1} and R ^2.

<Substituent group Z>
Examples of substituents that R ¹ , R ² , R ³¹ , R ³² , R ⁴¹ , R ⁴² , R ⁵¹ , R ⁵² , R ⁶¹ , R ⁶² , and Ar ^{1 to} Ar ⁴ may have are as follows. Any one selected from the substituent group Z can be used.

Examples of the substituent group Z include the following structures.
For example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, n-octyl group. , Dodecyl group, etc., which usually has 1 or more carbon atoms, preferably 4 or more, usually 24 or less, preferably 12 or less, linear, branched, or cyclic alkyl group;
For example, an alkenyl group such as a vinyl group having a carbon number of usually 2 or more, usually 24 or less, preferably 12 or less;
For example, an alkynyl group having a carbon number of usually 2 or more, usually 24 or less, preferably 12 or less, such as an ethynyl group;
For example, an alkoxy group such as a methoxy group or an ethoxy group having a carbon number of usually 1 or more, usually 24 or less, preferably 12 or less;
For example, an aryloxy group or a heteroaryloxy group having a carbon number of usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less, such as a phenoxy group, a naphthoxy group, and a pyridyloxy group;
For example, an alkoxycarbonyl group such as a methoxycarbonyl group or an ethoxycarbonyl group, which usually has 2 or more carbon atoms and usually has 24 or less, preferably 12 or less carbon atoms;
For example, a dialkylamino group such as a dimethylamino group or a diethylamino group, which usually has 2 or more carbon atoms and usually has 24 or less carbon atoms, preferably 12 or less carbon atoms;
For example, a diarylamino group having a carbon number of usually 10 or more, preferably 12 or more, usually 36 or less, preferably 24 or less, such as a diphenylamino group, a ditrilamino group, and an N-carbazolyl group;
For example, an arylalkylamino group having 7 or more carbon atoms, usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;
For example, an acyl group such as an acetyl group or a benzoyl group having a carbon number of usually 2 or more, usually 24 or less, preferably 12 or less;
For example, halogen atoms such as fluorine atoms and chlorine atoms;
For example, a haloalkyl group having usually 1 or more carbon atoms and usually 12 or less, preferably 6 or less carbon atoms, such as a trifluoromethyl group;
For example, an alkylthio group having a carbon number of usually 1 or more, usually 24 or less, preferably 12 or less, such as a methylthio group and an ethylthio group;
For example, an arylthio group having a carbon number of usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less, such as a phenylthio group, a naphthylthio group, or a pyridylthio group;
For example, a silyl group such as a trimethylsilyl group or a triphenylsilyl group having a carbon number of usually 2 or more, preferably 3 or more, and usually 36 or less, preferably 24 or less;
For example, a syroxy group having a carbon number of usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less, such as a trimethylsiloxy group or a triphenylsiloxy group;
Cyano group;
For example, an aromatic hydrocarbon group such as a phenyl group or a naphthyl group, which usually has 6 or more carbon atoms and usually 36 or less, preferably 24 or less carbon atoms;
For example, an aromatic heterocyclic group having a carbon number of usually 3 or more, preferably 4 or more, and usually 36 or less, preferably 24 or less, such as a thienyl group or a pyridyl group.

Among the above-mentioned substituent group Z, the above-mentioned alkyl group, alkoxy group, aromatic hydrocarbon group and aromatic heterocyclic group are preferable. From the viewpoint of charge transportability, it is more preferable to have no substituent.

Further, each substituent of the above-mentioned Substituent Group Z may further have a Substituent. As the substituents, the same ones as those of the above-mentioned substituents (substituent group Z) can be used.

<Specific example>
Specific examples of the aromatic diamine derivative represented by the formula (1) will be shown below, but the present invention is not limited thereto.

Among the above compounds, particularly preferable compounds include, for example, compound (A-10), compound (A-15), compound (A-21), and compound (A-22) (compound 1 described later).

Since these compounds have a benzoindeno-dibenzofuran skeleton with low symmetry, the molecules are less likely to aggregate with each other, and the luminous efficiency of the organic electroluminescent element can be improved. Further, these compounds have an alkyl group having 4 or more carbon atoms as a substituent, and can improve the solubility and film stability of the compound.

<Use of aromatic diamine derivatives>
The aromatic diamine derivative of the present invention can be suitably used as a material used for an organic electroluminescent element, that is, a blue light emitting material for an organic electroluminescent element, and can also be suitably used as a light emitting material for other light emitting elements and the like. be.

[OLED composition]
The aromatic diamine derivative of the present invention is preferably used together with a solvent. Hereinafter, a composition containing the aromatic diamine derivative of the present invention and a solvent (hereinafter, may be referred to as “OLED composition” or simply “composition”) will be described.

The composition for OLED of the present invention contains the above-mentioned aromatic diamine derivative and solvent. The composition for OLED of the present invention is usually used for forming a layer or a film by a wet film forming method, and is particularly preferably used for forming an organic layer of an organic electroluminescent device. The organic layer is particularly preferably a light emitting layer.

That is, the OLED composition of the present invention is preferably a composition for forming an organic layer of an organic electroluminescent device, and more preferably used as a composition for forming a light emitting layer of an organic electroluminescent device.

The content of the aromatic diamine derivative of the present invention in the composition for OLED is usually 0.001% by mass or more, preferably 0.01% by mass or more, usually 30.0% by mass or less, preferably 20.0% by mass or less. Is. By setting the aromatic diamine derivative in the composition in this range, holes and electrons are efficiently injected from the adjacent layer (for example, the hole transporting layer and the hole blocking layer) into the light emitting layer to drive the light emitting layer. The voltage can be reduced. The aromatic diamine derivative of the present invention may be contained in the composition of only one type or in combination of two or more types.

When the composition for OLED of the present invention is used, for example, for forming an organic layer of an organic electroluminescent element, in addition to the above-mentioned aromatic diamine derivative and solvent, a charge transporting compound used for the organic electroluminescent element, particularly the light emitting layer. Can be contained.

When the light emitting layer of the organic electric field light emitting element is formed by using the composition for OLED of the present invention, the aromatic diamine derivative of the present invention is used as a light emitting material, and another charge transporting compound is contained as a charge transport host material. Is preferable.

The solvent contained in the composition for OLED of the present invention is a volatile liquid component used for forming a layer containing an aromatic diamine derivative by wet film formation.

The solvent is not particularly limited as long as it is an organic solvent in which the aromatic diamine derivative of the present invention which is a solute and the charge transporting compound described later are well dissolved.

Preferred solvents include, for example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, phenylcyclohexane, tetralin; chlorobenzene, dichlorobenzene, trichlorobenzene and the like. Halogenized aromatic hydrocarbons such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetol, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, etc. Aromatic ethers such as 2,4-dimethylanisole and diphenyl ether; aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate, cyclohexanone, cycloocta Alicyclic ketones such as non- and fencon; alicyclic alcohols such as cyclohexanol and cyclooctanol; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; aliphatic alcohols such as butanol and hexanol; ethylene glycol dimethyl ether and ethylene Hydrocarbon ethers such as glycol diethyl ether and propylene glycol-1-monomethyl ether acetate (PGMEA); and the like.

Of these, alkanes, aromatic hydrocarbons, and aromatic esters are preferable, and phenylcyclohexane and aromatic esters in particular have a preferable viscosity and boiling point.

One of these solvents may be used alone, or two or more of these solvents may be used in any combination and ratio.

The boiling point of the solvent used is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and usually 350 ° C. or lower, preferably 330 ° C. or lower, more preferably 300 ° C. or lower. If the boiling point of the solvent is lower than this range, the film formation stability may decrease due to solvent evaporation from the composition during wet film formation. If the boiling point of the solvent exceeds this range, the film formation stability may decrease due to the solvent remaining after the film formation during the wet film formation.

In particular, a uniform coating film can be produced by combining two or more of the above solvents with a solvent having a boiling point of 150 ° C. or higher. If the number of solvents having a boiling point of 150 ° C. or higher is one or less, it is considered that a uniform film may not be formed at the time of coating.

The content of the solvent in the composition for OLED is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, and preferably 99.99% by mass or less, more preferably 99. It is 90% by mass or less, particularly preferably 99.00% by mass or less.

Normally, the thickness of the light emitting layer is about 3 to 200 nm, but if the content of the solvent is less than this lower limit, the viscosity of the composition becomes too high, and the film forming workability may be lowered. On the other hand, if the content of the solvent exceeds this upper limit, the thickness of the film obtained by removing the solvent after the film formation becomes insufficient, and the film formation tends to be difficult.

As the other charge-transporting compound that can be contained in the above-mentioned composition for OLED of the present invention, those conventionally used as materials for an organic electroluminescent device can be used. For example, pyridine, carbazole, naphthalene, perylene, pyrene, anthracene, chrysen, naphthalene, phenanthrene, coronen, fluorantene, benzophenanthrene, fluorene, acetnaphthofluoranthene, coumarin, p-bis (2-phenylethenyl) benzene and theirs. Derivatives, quinacridone derivatives, DCM (4- (dicyanomethyrene) -2-methyl-6- (p-dimethylaminostyly) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene, aryl Examples thereof include a fused aromatic ring compound in which an amino group is substituted, a styryl derivative in which an arylamino group is substituted, and the like.

One of these may be used alone, or two or more of them may be used in any combination and ratio.

The content of the other charge-transporting compound in the OLED composition is usually 1000 parts by mass or less, preferably 100 parts by mass, based on 1 part by mass of the aromatic diamine derivative of the present invention in the OLED composition. Hereinafter, it is more preferably 50 parts by mass or less, and usually 0.01 part by mass or more, preferably 0.1 part by mass or more, still more preferably 1 part by mass or more.

If necessary, the composition for OLED of the present invention may contain other compounds in addition to the above compounds. Other compounds preferably include phenols such as dibutylhydroxytoluene, which is known as an antioxidant, and dibutylphenol.

[Organic electroluminescent device]
An organic electroluminescent device (hereinafter, may be referred to as "organic electroluminescent device of the present invention") can be manufactured using the aromatic diamine derivative of the present invention. The organic electroluminescent device of the present invention containing the aromatic diamine derivative of the present invention will be described below.

The organic electroluminescent element of the present invention preferably has at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, and at least one of the organic layers is Contains the aromatic diamine derivative of the present invention. The organic layer includes a light emitting layer.

The organic layer containing the aromatic diamine derivative of the present invention is more preferably a layer formed by using the composition of the present invention, and further preferably a layer formed by a wet film forming method. The layer formed by the wet film forming method is preferably the light emitting layer.

In the present invention, the wet film forming method refers to a method of drying a film formed to form a film. As a film forming method, that is, as a coating method, for example, a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, a capillary coating method, an inkjet method, a nozzle printing method, A wet film forming method such as a screen printing method, a gravure printing method, or a flexographic printing method can be adopted.

FIG. 1 is a schematic cross-sectional view showing a structural example suitable for the organic electroluminescent element 10 of the present invention. In FIG. 1, reference numeral 1 is a substrate, reference numeral 2 is an anode, reference numeral 3 is a hole injection layer, and reference numeral 4 is a hole injection layer. The hole transport layer, reference numeral 5 is a light emitting layer, reference numeral 6 is a hole blocking layer, reference numeral 7 is an electron transport layer, reference numeral 8 is an electron injection layer, and reference numeral 9 is a cathode.

As the material applied to these structures, known materials can be applied, and there is no particular limitation, but typical materials and manufacturing methods for each layer are described below as an example. In addition, when quoting publications, treatises, etc., the relevant contents can be appropriately applied and applied within the scope of common sense of those skilled in the art.

<Board 1>
The substrate 1 serves as a support for an organic electroluminescent element, and usually a quartz or glass plate, a metal plate, a metal foil, a plastic film, a sheet, or the like is used. Of these, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferable. The substrate 1 is preferably made of a material having a high gas barrier property because the organic electroluminescent element is unlikely to be deteriorated by the outside air. Therefore, particularly when a material having a low gas barrier property such as a synthetic resin substrate is used, it is preferable to provide a dense silicon oxide film or the like on at least one surface of the substrate 1 to improve the gas barrier property.

<Anode 2>
The anode 2 has a function of injecting holes into the layer on the light emitting layer side. The anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum; a metal oxide such as an oxide of indium and / or tin; a metal halide such as copper iodide; carbon black or poly (3). -Methylthiophene), polypyrrole, polyaniline and other conductive polymers.

The anode 2 is usually formed by a dry method such as a sputtering method or a vacuum vapor deposition method. Further, when the anode 2 is formed by using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc., an appropriate binder resin solution is used. It can also be formed by dispersing it in a film and applying it on a substrate. Further, in the case of a conductive polymer, a thin film can be formed directly on the substrate by electrolytic polymerization, or an anode 2 can be formed by applying the conductive polymer on the substrate (Appl. Phys. Lett., Volume 60, p. 2711, 1992).

The anode 2 usually has a single-layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, different conductive materials may be laminated on the first-layer anode.

The thickness of the anode 2 may be determined according to the required transparency, material, and the like. When particularly high transparency is required, a thickness having a visible light transmittance of 60% or more is preferable, and a thickness having a visible light transmittance of 80% or more is more preferable. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. On the other hand, when transparency is not required, the thickness of the anode 2 may be arbitrarily set according to the required strength and the like. In this case, the anode 2 may have the same thickness as the substrate 1.

When forming a film on the surface of the anode 2, impurities on the anode are removed and the ionization potential thereof is adjusted by performing treatments such as ultraviolet rays + ozone, oxygen plasma, and argon plasma before the film formation. It is preferable to improve the hole injection property.

<Hole injection layer 3>
The layer having a function of transporting holes from the anode 2 side to the light emitting layer 5 side is usually called a hole injection transport layer or a hole transport layer. When there are two or more layers having a function of transporting holes from the anode 2 side to the light emitting layer 5, the layer closer to the anode 2 side may be referred to as the hole injection layer 3. The hole injection layer 3 is preferably used because it enhances the function of transporting holes from the anode 2 to the light emitting layer 5. When the hole injection layer 3 is used, the hole injection layer 3 is usually formed on the anode 2.

The film thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

The hole injection layer 3 may be formed by either a vacuum vapor deposition method or a wet film deposition method. In terms of excellent film forming property, it is preferably formed by a wet film forming method.

The hole injection layer 3 preferably contains a hole transporting compound, and more preferably contains a hole transporting compound and an electron accepting compound. Further, the hole injection layer 3 preferably contains a cationic radical compound, and particularly preferably contains a cationic radical compound and a hole transporting compound.

(Hole transporting compound)
The composition for forming a hole injection layer usually contains a hole transporting compound that becomes the hole injection layer 3. Further, in the case of the wet film forming method, a solvent is usually further contained. The composition for forming a hole injection layer is preferably a composition having high hole transportability and capable of efficiently transporting the injected holes. Therefore, it is preferable that the hole mobility is high and impurities that serve as traps are unlikely to be generated during production or use. Further, it is preferable that the stability is excellent, the ionization potential is small, and the transparency to visible light is high. In particular, when the hole injection layer 3 is in contact with the light emitting layer 5, those that do not quench the light emitted from the light emitting layer 5 or those that form an exciplex with the light emitting layer 5 and do not reduce the luminous efficiency are preferable.

As the hole transporting compound, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferable from the viewpoint of a charge injection barrier from the anode 2 to the hole injection layer 3. Examples of hole-transporting compounds include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which a tertiary amine is linked with a fluorene group, and hydrazone. Examples thereof include system compounds, silazane compounds, and quinacridone compounds.

Among the above-mentioned exemplified compounds, an aromatic amine compound is preferable, and an aromatic tertiary amine compound is particularly preferable from the viewpoint of amorphousness and visible light transmission. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and also includes a compound having a group derived from the aromatic tertiary amine.

The type of aromatic tertiary amine compound is not particularly limited, but is a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (polymerized compound in which repeating units are continuous) from the viewpoint that uniform light emission can be easily obtained due to the surface smoothing effect. Is preferably used. Preferred examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (I).

(In the formula (I), Ar ⁵¹ and Ar ⁵² are each independently, .Ar ⁵³ representing a good heteroaromatic group optionally also have an aromatic group or a substituent substituted ~ Ar ⁵⁵ each independently represents an aromatic group which may have a substituent or a complex aromatic group which may have a substituent. Q is from the following linking group group. Represents the linking group of choice. Further, of Ar ^{51 to} Ar ⁵⁵ , two groups bonded to the same N atom may be bonded to each other to form a ring.)

The linking groups are shown below.

(In the above formulas, Ar ⁵⁶ to Ar ⁶⁶ are each independently, .R represents an heteroaromatic group optionally having also an aromatic group or a substituent substituted ^a ~ R ^b independently represents a hydrogen atom or any substituent.)

The aromatic groups and heteroaromatic groups of Ar ^{51 to} Ar ⁶⁶ include benzene ring, naphthalene ring, phenanthrene ring, thiophene ring, and pyridine ring from the viewpoint of solubility, heat resistance, and hole injection transportability of the polymer compound. Derived groups are preferable, and groups derived from benzene rings and naphthalene rings are preferable.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the formula (I) include those described in International Publication No. 2005/089024.

(Electron accepting compound)
Since the hole injection layer 3 can improve the conductivity of the hole injection layer 3 by oxidizing the hole transporting compound, it is preferable that the hole injection layer 3 contains an electron accepting compound.

As the electron-accepting compound, a compound having an oxidizing power and having an ability to accept one electron from the above-mentioned hole-transporting compound is preferable, and specifically, a compound having an electron affinity of 4 eV or more is preferable, and an electron affinity is preferable. A compound having a value of 5 eV or more is more preferable.

Such an electron-accepting compound includes, for example, a triarylboron compound, a metal halide, a Lewis acid, an organic acid, an onium salt, a salt of an arylamine and a metal halide, and a salt of an arylamine and a Lewis acid. Examples thereof include one or more compounds selected from the group.

Specifically, an onium salt substituted with an organic group such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium tetrafluoroborate (International Publication No. 2005/089024); chloride. High valence inorganic compounds such as iron (III) (Japanese Patent Laid-Open No. 11-251067), ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; tris (pentafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-313665) Aromatic boron compounds such as; fullerene derivatives, iodine and the like.

(Cation radical compound)
As the cation radical compound, an ionic compound composed of a cation radical, which is a chemical species obtained by removing one electron from a hole transporting compound, and a counter anion is preferable. However, when the cation radical is derived from a hole-transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

The cation radical is preferably a chemical species obtained by removing one electron from the above-mentioned compound as a hole-transporting compound. A chemical species obtained by removing one electron from a preferable compound as a hole transporting compound is preferable from the viewpoints of amorphousness, visible light transmittance, heat resistance, solubility and the like.

Here, the cationic radical compound can be produced by mixing the hole transporting compound and the electron accepting compound described above. That is, by mixing the above-mentioned hole transporting compound and the electron accepting compound, electron transfer occurs from the hole transporting compound to the electron accepting compound, and the cation radical and the counter anion of the hole transporting compound become A cationic ion compound consisting of is produced.

Cationic radical compounds derived from polymer compounds such as PEDOT / PSS (Adv. Mater., 2000, Vol. 12, p. 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, Vol. 94, p. 7716) It is also produced by oxidative polymerization (dehydropolymerization).

The oxidative polymerization referred to here is to chemically or electrochemically oxidize a monomer in an acidic solution using peroxodisulfate or the like. In the case of this oxidative polymerization (dehydropolymerization), a cation radical obtained by removing one electron from a repeating unit of a polymer, which is polymerized by oxidizing a monomer and has an anion derived from an acidic solution as a counter anion, is generated. Generate.

(Formation of hole injection layer 3 by wet film formation method)
When the hole injection layer 3 is formed by the wet film formation method, the material to be the hole injection layer 3 is usually mixed with a solvent in which the material is soluble (a solvent for the hole injection layer) for film formation. A composition (composition for forming a hole injection layer) is prepared, and the composition for forming a hole injection layer is applied onto a layer (usually, an anode 2) corresponding to the lower layer of the hole injection layer 3 by a wet film forming method. It is formed by forming a film and drying it. The film formed can be dried in the same manner as the drying method in forming the light emitting layer 5 by the wet film forming method.

The concentration of the hole transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, but in terms of film thickness uniformity, a lower concentration is preferable, while positive. A higher value is preferable in that defects are less likely to occur in the hole injection layer 3. Specifically, it is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and on the other hand, 70% by mass. It is preferably less than or equal to, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents and the like.

Examples of the ether-based solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, and anisole. , Fenetol, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole and other aromatic ethers.

Examples of the ester-based solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.

Examples of the aromatic hydrocarbon-based solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, methylnaphthalene and the like.

Examples of the amide-based solvent include N, N-dimethylformamide, N, N-dimethylacetamide and the like.

In addition to these, dimethyl sulfoxide and the like can also be used. Preferably, it is an aromatic hydrocarbon solvent and an aromatic ester solvent.

The formation of the hole injection layer 3 by the wet film formation method is usually performed on the layer corresponding to the lower layer of the hole injection layer 3 (usually, the anode 2) after preparing the composition for forming the hole injection layer. It is carried out by applying a film to the film and drying it. In the hole injection layer 3, the coating film is usually dried by heating, vacuum drying, or the like after the film formation.

(Formation of hole injection layer 3 by vacuum vapor deposition method)
When the hole injection layer 3 is formed by the vacuum vapor deposition method, usually one or more of the constituent materials of the hole injection layer 3 (the above-mentioned hole transporting compound, electron accepting compound, etc.) are vacuumed. Place in a crucible installed inside the container (when using two or more materials, usually put each in a separate crucible), ^{exhaust the inside of the vacuum container to about 10-4} Pa with a vacuum pump, and then heat the crucible. (When two or more types of materials are used, each crucible is usually heated), and the material in the crucible is evaporated while controlling the amount of evaporation (when two or more types of materials are used, each is usually independent). Evaporates while controlling the amount of evaporation) to form the hole injection layer 3 on the anode 2 on the substrate placed facing the crucible. When two or more kinds of materials are used, a mixture thereof can be put in a crucible and heated and evaporated to form the hole injection layer 3.

The degree of vacuum during vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 × 10 ^-6 Torr (0.13 × 10 ^-4 Pa) or more, 9.0 × 10 ^-6 Torr ( It is 12.0 × 10 ^-4 Pa) or less. The vapor deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The film formation temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 10 ° C. or higher and 50 ° C. or lower.

<Hole transport layer 4>
The hole transport layer 4 is a layer that has a function of transporting holes from the anode 2 side to the light emitting layer 5. The hole transport layer 4 is not an essential layer in the organic electroluminescent device of the present invention, but it is preferable to provide this layer from the viewpoint of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5. When the hole transport layer 4 is provided, the hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5. Further, when the hole injection layer 3 described above is present, it is formed between the hole injection layer 3 and the light emitting layer 5.

The film thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and on the other hand, usually 300 nm or less, preferably 100 nm or less.

The hole transport layer 4 may be formed by either a vacuum vapor deposition method or a wet film deposition method. In terms of excellent film forming property, it is preferably formed by a wet film forming method.

The hole transport layer 4 usually contains a hole transport compound that becomes the hole transport layer 4. Examples of the hole-transporting compound contained in the hole-transporting layer 4 include two or more tertiary compounds represented by 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl. Aromatic diamine containing amine and having two or more condensed aromatic rings replaced with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681), 4,4', 4''-tris (1-naphthylphenylamino) triphenylamine Aromatic amine compounds having a starburst structure such as (J. Lumin., 72-74, pp. 985, 1997), aromatic amine compounds consisting of triphenylamine tetramers (Chem. Commun., P. 2175). , 1996), 2,2', 7,7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene and other spiro compounds (Synth. Metals, Vol. 91, p. 209, 1997), 4 , 4'-N, N'-dicarbazole Biphenyl and other carbazole derivatives and the like can be mentioned. Further, for example, polyvinylcarbazole, polyvinyltriphenylamine (Japanese Patent Laid-Open No. 7-53953), polyarylene ether sulfone containing tetraphenylbenzidine (Polym. Adv. Tech., Vol. 7, p. 33, 1996) and the like are also available. It can be preferably used.

(Formation of hole transport layer 4 by wet film formation method)
When the hole transport layer 4 is formed by the wet film forming method, usually, in the same manner as when the hole injection layer 3 is formed by the wet film forming method, instead of the hole injection layer forming composition. It is formed using a composition for forming a hole transport layer.

When the hole transport layer 4 is formed by the wet film forming method, the hole transport layer forming composition usually further contains a solvent. As the solvent used in the hole transport layer forming composition, the same solvent as the solvent used in the hole injection layer forming composition described above can be used.

The concentration of the hole-transporting compound in the composition for forming the hole-transporting layer can be in the same range as the concentration of the hole-transporting compound in the composition for forming the hole-injecting layer.

The hole transport layer 4 can be formed by the wet film formation method in the same manner as the hole injection layer 3 film formation method described above.

(Formation of hole transport layer 4 by vacuum vapor deposition method)
Even when the hole transport layer 4 is formed by the vacuum vapor deposition method, it is usually positive instead of the constituent material of the hole injection layer 3 in the same manner as when the hole injection layer 3 is formed by the vacuum vapor deposition method. It can be formed using the constituent material of the hole transport layer 4. The film formation conditions such as the degree of vacuum, the vapor deposition rate, and the temperature at the time of vapor deposition can be the same as those at the time of vacuum deposition of the hole injection layer 3.

<Light emitting layer 5>
The light emitting layer 5 is a layer having a function of emitting light by being excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 when an electric field is applied between the pair of electrodes. .. The light emitting layer 5 is a layer formed between the anode 2 and the cathode 9, and the light emitting layer 5 is between the hole injection layer 3 and the cathode 9 when the hole injection layer 3 is above the anode 2. If there is a hole transport layer 4 on the anode 2, it is formed between the hole transport layer 4 and the cathode 9.

The film thickness of the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired. .. Therefore, the film thickness of the light emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, and on the other hand, preferably 200 nm or less, and further preferably 100 nm or less.

The light emitting layer 5 contains at least a material having a light emitting property (light emitting material) and preferably a material having a charge transporting property (charge transporting material). As the light emitting material, any light emitting layer may contain the aromatic diamine derivative of the present invention, and other light emitting materials may be used as appropriate. Hereinafter, light emitting materials other than the aromatic diamine derivative of the present invention will be described in detail.

(Luminescent material)
As the light emitting material, other light emitting materials can be used in combination with the aromatic diamine derivative represented by the formula (1) as long as the light emitting material emits light at a desired light emitting wavelength and the effect of the present invention is not impaired. The light emitting material may be either a fluorescent light emitting material or a phosphorescent light emitting material, but a material having good luminous efficiency is preferable, and a phosphorescent light emitting material is preferable from the viewpoint of light emitting efficiency of the organic electric field light emitting element.

Examples of the fluorescent light emitting material include the following materials.

Examples of the fluorescent light emitting material (blue fluorescent light emitting material) that gives blue light emission include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis (2-phenylethenyl) benzene, and derivatives thereof.

The fluorescent light-emitting material giving green luminescence (green fluorescent material), for example, quinacridone derivatives, coumarin _derivatives, aluminum complexes such as _{Al (C 9 H 6 NO)} 3 and the like.

Examples of the fluorescent light emitting material (yellow fluorescent light emitting material) that gives yellow light emission include rubrene, a perimidone derivative, and the like.

Examples of the fluorescent light emitting material (red fluorescent light emitting material) that gives red light emission include DCM (4- (dicyanomethyrene) -2-methyl-6- (p-dimethylaminostylyl) -4H-pyran) compounds, benzopyran derivatives, and rhodamine derivatives. , Benzothioxanthene derivatives, azabenzothioxanthene and the like.

Further, as the phosphorescent material, for example, the 7th to 11th of the long periodic table (hereinafter, unless otherwise specified, the term "periodic table" refers to the long periodic table). Examples thereof include organic metal complexes containing metals selected from the group. Preferred metals selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, renium, osmium, iridium, platinum, gold and the like.

As the ligand of the organic metal complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand is linked to a pyridine, pyrazole, phenanthroline or the like is preferable. In particular, a phenylpyridine ligand and a phenylpyrazole ligand are preferable. Here, the (hetero) aryl represents an aryl group or a heteroaryl group.

Specific preferred phosphorescent materials include, for example, tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, and tris. Examples thereof include phenylpyridine complexes such as (2-phenylpyridine) osmium and tris (2-phenylpyridine) renium, and porphyrin complexes such as octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethyl palladium porphyrin, and octaphenyl palladium porphyrin.

Polymer-based luminescent materials include poly (9,9-dioctylfluorene-2,7-diyl) and poly [(9,9-dioctylfluorene-2,7-diyl) -co- (4,4'-). (N- (4-sec-butylphenyl)) diphenylamine)], poly [(9,9-dioctylfluorene-2,7-diyl) -co- (1,4-benzo-2 {2,1'-3) } -Triazole)] and other polyfluorene-based materials, and poly-phenylene vinylene-based materials such as poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene] can be mentioned.

(Charge transport material)
The charge transporting material is a material having positive charge (hole) or negative charge (electron) transportability, and is not particularly limited as long as the effects of the present invention are not impaired, and known materials can be applied.

As the charge transporting material, a compound or the like conventionally used for the light emitting layer 5 of the organic electroluminescent element can be used, and a compound used as a host material for the light emitting layer 5 is particularly preferable.

Specific examples of the charge transporting material include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, and compounds in which a tertiary amine is linked with a fluorene group. , Hydrazone-based compounds, silazane-based compounds, silanamine-based compounds, phosphamine-based compounds, quinacridone-based compounds, and other compounds exemplified as hole-transporting compounds in the hole injection layer 3, as well as anthracene-based compounds and pyrene-based compounds. , Carbazole-based compounds, pyridine-based compounds, phenanthroline-based compounds, oxadiazole-based compounds, silol-based compounds and other electron-transporting compounds.

Further, for example, two or more fused aromatic rings containing two or more tertiary amines represented by 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are used as nitrogen atoms. Aromatic amine compounds having a starburst structure, such as substituted aromatic diamines (Japanese Patent Laid-Open No. 5-234681), 4,4', 4''-tris (1-naphthylphenylamino) triphenylamine, etc. Lumin., 72-74, 985, 1997), aromatic amine compounds consisting of triphenylamine tetramers (Chem. Commun., 2175, 1996), 2, 2', 7, 7 Fluorene compounds such as'-tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, Vol. 91, p. 209, 1997), 4,4'-N, N'-dicarbazolebiphenyl. Compounds exemplified as the hole-transporting compound of the hole-transporting layer 4 such as carbazole-based compounds such as the above can also be preferably used. In addition, 2- (4-biphenylyl) -5- (p-tershalbutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1-naphthyl)- Oxadiazole compounds such as 1,3,4-oxadiazole (BND), 2,5-bis (6'-(2', 2 "-bipyridyl))-1,1-dimethyl-3,4- Examples thereof include silol compounds such as diphenylsilol (PyPySPyPy), phenanthroline compounds such as vasophenanthroline (BPhen) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproine).

(Formation of light emitting layer 5 by wet film formation method)
The light emitting layer 5 may be formed by either a vacuum vapor deposition method or a wet film forming method, but the wet film forming method is preferable because of its excellent film forming property.

When the light emitting layer 5 is formed by the wet film forming method, usually, in the same manner as when the hole injection layer 3 is formed by the wet film forming method, light emission is performed instead of the composition for forming the hole injection layer. The material to be layer 5 is formed by using a light emitting layer forming composition prepared by mixing with a soluble solvent (solvent for light emitting layer). In the present invention, it is preferable to use the above-mentioned OLED composition of the present invention as the light emitting layer forming composition.

Examples of the solvent include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents mentioned for the formation of the hole injection layer 3, as well as alcohol-based solvents, halogenated aromatic hydrocarbon-based solvents, and fats. Examples thereof include group alcohol solvents, alicyclic alcohol solvents, aliphatic ketone solvents and alicyclic ketone solvents. The solvent used is as exemplified as the solvent of the composition for OLED of the present invention, and specific examples of the solvent are given below, but the solvent is not limited thereto as long as the effect of the present invention is not impaired.

For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetol, 2 Aromatic ether solvents such as −methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, diphenyl ether; phenyl acetate, phenyl propionate, methyl benzoate, benzoic acid Aromatic ester solvents such as ethyl, propyl benzoate, n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4 -Aromatic hydrocarbon solvents such as diisopropylbenzene and methylnaphthalene; amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide; alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin and bicyclohexane Solvents: Halogenized aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; alicyclic alcohol solvents such as cyclohexanol and cyclooctanol; methyl ethyl ketone and dibutyl ketone Such as aliphatic ketone solvent; cyclohexanone, cyclooctanone, alicyclic ketone solvent such as fencon and the like can be mentioned. Of these, alkane-based solvents, aromatic hydrocarbon-based solvents, and aromatic ester-based solvents are particularly preferable.

Further, in order to obtain a more uniform film, it is preferable that the solvent evaporates at an appropriate rate from the liquid film immediately after the film formation. Therefore, as described above, the boiling point of the solvent used is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and usually 270 ° C. or lower, preferably 250 ° C. or lower, more preferably 230 ° C. or higher. It is as follows.

The amount of the solvent used is arbitrary as long as the effect of the present invention is not significantly impaired, but the larger the total content of the solvent in the light emitting layer forming composition, that is, the OLED composition, the lower the viscosity and the film forming operation. On the other hand, the smaller the amount, the easier it is to form a thick film. As described above, the content of the solvent is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, and preferably 99.99% by mass or less in the composition for OLED. It is preferably 99.90% by mass or less, and particularly preferably 99.00% by mass or less.

As a method for removing the solvent after the wet film formation, heating or depressurization can be used. As the heating means used in the heating method, a clean oven and a hot plate are preferable because heat is evenly applied to the entire film.

The heating temperature in the heating step is arbitrary as long as the effect of the present invention is not significantly impaired, but it is preferably high in terms of shortening the heating time and preferably low in terms of less damage to the material. The upper limit of the heating temperature is usually 250 ° C. or lower, preferably 200 ° C. or lower, and more preferably 150 ° C. or lower. The lower limit of the heating temperature is usually 30 ° C. or higher, preferably 50 ° C. or higher, and more preferably 80 ° C. or higher. A temperature exceeding the above upper limit is higher than the heat resistant temperature of the normally used charge transport material or phosphorescent material, and the charge transport material or phosphorescent material may be decomposed or crystallized, which is not preferable. If the temperature is less than the above lower limit, it takes a long time to remove the solvent, which is not preferable. The heating time in the heating step is appropriately determined by the boiling point and vapor pressure of the solvent in the composition for forming the light emitting layer, the heat resistance of the material, and the heating conditions.

(Formation of light emitting layer 5 by vacuum vapor deposition method)
When the light emitting layer 5 is formed by the vacuum deposition method, usually one or more kinds of constituent materials of the light emitting layer 5 (the above-mentioned light emitting material, charge transporting compound, etc.) are installed in a crucible in a vacuum vessel. (When using two or more types of materials, usually put each in a separate crucible), ^{exhaust the inside of the vacuum vessel to about 10-4} Pa with a vacuum pump, and then heat the crucible (two or more types). When using materials, usually heat each crucible) and evaporate while controlling the amount of evaporation of the material in the crucible (when using two or more types of materials, usually while controlling the amount of evaporation independently). Evaporate) to form a light emitting layer 5 on the hole injection layer 3 or the hole transport layer 4 placed facing the crucible. When two or more kinds of materials are used, a mixture thereof can be put in a crucible and heated and evaporated to form the light emitting layer 5.

The degree of vacuum during vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 × 10 ^-6 Torr (0.13 × 10 ^-4 Pa) or more, 9.0 × 10 ^-6 Torr ( It is 12.0 × 10 ^-4 Pa) or less. The vapor deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The film formation temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is preferably 10 ° C. or higher and 50 ° C. or lower.

<Hole blocking layer 6>
A hole blocking layer 6 may be provided between the light emitting layer 5 and the electron injection layer 8 described later. The hole blocking layer 6 is a layer laminated on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.

The hole blocking layer 6 has a role of blocking holes moving from the anode 2 from reaching the cathode 9 and a role of efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. Has. The physical properties required for the material constituting the hole blocking layer 6 are high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and an excited triplet level (T1). Is high.

Examples of the material of the hole blocking layer 6 satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenanthroline) aluminum and bis (2-methyl-8-quinolinolato) (triphenylsilanorat) aluminum. Mixed ligand complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinolato) aluminum dinuclear metal complexes and other metal complexes, distyrylbiphenyl derivatives, etc. Styryl compounds (Japanese Patent Laid-Open No. 11-2429996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole and other triazole derivatives (Japanese Patent Laid-Open No. 11-24296). 7-41759A), phenanthroline derivatives such as bathocuproine (Japanese Unexamined Patent Publication No. 10-79297), and the like can be mentioned. Further, a compound having at least one pyridine ring in which the 2, 4 and 6 positions are substituted as described in WO 2005/022962 is also preferable as a material for the hole blocking layer 6.

The method for forming the hole blocking layer 6 is not limited, and the hole blocking layer 6 can be formed in the same manner as the method for forming the light emitting layer 5 described above.

The film thickness of the hole blocking layer 6 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less. be.

<Electron transport layer 7>
The electron transport layer 7 is provided between the light emitting layer 5 or the hole element layer 6 and the electron injection layer 8 for the purpose of further improving the current efficiency of the organic electroluminescent device.

The electron transport layer 7 is formed of a compound capable of efficiently transporting electrons injected from the cathode 9 in the direction of the light emitting layer 5 between the electrodes to which an electric field is applied. As the electron-transporting compound used in the electron-transporting layer 7, the electron-injecting efficiency from the cathode 9 or the electron-injecting layer 8 is high, and the injected electrons can be efficiently transported with high electron mobility. Must be a compound.

Specific examples of the electron-transporting compound satisfying such conditions include a metal complex such as an aluminum complex of 8-hydroxyquinolin (Japanese Patent Laid-Open No. 59-194393), 10-hydroxybenzo [h] quinoline. Metal Complex, Oxaziazole Derivative, Distyrylbiphenyl Derivative, Sirol Derivative, 3-Hydroxyflavon Metal Complex, 5-Hydroxyflavon Metal Complex, Benzoxazole Metal Complex, Benthiazole Metal Complex, Trisbenzimidazolylbenzene (US Patent No. 5645948) No. ), Kinoxalin compound (Japanese Patent Laid-Open No. 6-207169), phenanthroline derivative (Japanese Patent Laid-Open No. 5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n Examples thereof include type hydride amorphous silicon carbide, type n-type zinc sulfide, and type n-type zinc selenium.

The film thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and on the other hand, usually 300 nm or less, preferably 100 nm or less.

The electron transport layer 7 is formed by laminating on the light emitting layer 5 or the hole blocking layer 6 by a wet film forming method or a vacuum vapor deposition method in the same manner as the light emitting layer 5. Usually, the vacuum deposition method is used.

<Electron injection layer 8>
The electron injection layer 8 plays a role of efficiently injecting the electrons injected from the cathode 9 into the electron transport layer 7 or the light emitting layer 5.

In order to efficiently perform electron injection, the material forming the electron injection layer 8 is preferably a metal having a low work function. As an example, alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the like are used.

The film thickness of the electron injection layer 8 is preferably 0.1 to 5 nm.

Further, an ultrathin insulating film (thickness of about 0.1 to 5 nm) such _{as LiF, MgF 2} , Li ₂ O, Cs ₂ CO ₃ is inserted as an electron injection layer 8 at the interface between the cathode 9 and the electron transport layer 7. This is also an effective method for improving the luminous efficiency of the organic electroluminescent element (Appl. Phys. Lett., Vol. 70, p. 152, 1997; JP-A-10-74586; IEEETrans. Electron. Devices, et al. Volume 44, p. 1245, 1997; SID 04 Digest, p. 154).

Further, an organic electron transport material represented by a nitrogen-containing heterocyclic compound such as basophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium (). (Described in JP-A No. 10-270171, JP-A-2002-100478, JP-A-2002-1000482, etc.), it is possible to improve electron injection and transportability and achieve both excellent film quality. preferable. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, usually 200 nm or less, preferably 100 nm or less.

The electron injection layer 8 is formed by laminating on the light emitting layer 5 or the hole blocking layer 6 or the electron transport layer 7 on the light emitting layer 5 by a wet film forming method or a vacuum vapor deposition method in the same manner as the light emitting layer 5.
The details in the case of the wet film forming method are the same as in the case of the light emitting layer 5 described above.

<Cathode 9>
The cathode 9 plays a role of injecting electrons into a layer on the light emitting layer 5 side (electron injection layer 8 or light emitting layer 5 or the like). As the material of the cathode 9, the material used for the anode 2 can be used, but in order to efficiently inject electrons, it is preferable to use a metal having a low work function, for example, tin and magnesium. , Indium, calcium, aluminum, metals such as silver or alloys thereof are used. Specific examples include alloy electrodes having a low work function such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In terms of the stability of the organic electroluminescent device, it is preferable to laminate a metal layer having a high work function and stable with respect to the atmosphere on the cathode 9 to protect the cathode 9 made of a metal having a low work function. .. Examples of the metal to be laminated include metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum.
The film thickness of the cathode is usually the same as that of the anode 2.

<Other constituent layers>
The above description has focused on the layered organic electroluminescent device shown in FIG. 1, but the performance between the anode 2 and the cathode 9 and the light emitting layer 5 in the organic electroluminescent device of the present invention has not been impaired. In addition to the layers described above, any layer may be provided, or any layer other than the light emitting layer 5 may be omitted.

For example, it is also effective to provide an electron blocking layer between the hole transporting layer 4 and the light emitting layer 5 for the same purpose as the hole blocking layer 8. The electron blocking layer prevents electrons moving from the light emitting layer 5 from reaching the hole transporting layer 4, thereby increasing the recombination probability with holes in the light emitting layer 5 and generating excitons. It has a role of confining the holes in the light emitting layer 5 and a role of efficiently transporting the holes injected from the hole transport layer 4 in the direction of the light emitting layer 5.

The characteristics required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Further, when the light emitting layer 5 is formed by the wet film forming method, it is preferable to form the electron blocking layer by the wet film forming method because the organic electroluminescent device can be easily manufactured.

Therefore, it is preferable that the electron blocking layer also has wet film formation compatibility, and the material used for such an electron blocking layer is a copolymer of dioctylfluorene and triphenylamine represented by F8-TFB (international). Publication No. 2004/084260) and the like.

The structure opposite to that of FIG. 1, that is, the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, the hole transport layer 4, and the hole injection layer 3 on the substrate 1. , The anode 2 can be laminated in this order, and the organic electroluminescent device of the present invention can be provided between two substrates having at least one of which is highly transparent.

Further, it is also possible to have a structure in which a plurality of layers shown in FIG. 1 are stacked (a structure in which a plurality of light emitting units are stacked). In that case, instead of the interface layer between the stages (between the light emitting units) (the anode is ITO (indium tin oxide), and the cathode is Al, the two layers), for example, V ₂ O ₅ or the like is charged. When used as, the barrier between the stages is reduced, which is more preferable from the viewpoint of luminous efficiency and drive voltage.

The present invention can be applied to any of a single element, an element having a structure arranged in an array, and a structure in which an anode and a cathode are arranged in an XY matrix.

[Display device and lighting device]
A display device and a lighting device can be manufactured using the organic electroluminescent element of the present invention. The type and structure of the display device and the lighting device using the organic electroluminescent element of the present invention are not particularly limited, and can be assembled according to a conventional method using the organic electroluminescent element of the present invention.

For example, the organic electroluminescent device of the present invention can be obtained by a method as described in "Organic EL Display" (Ohm Co., Ltd., published on August 20, 2004, by Shizushi Tokito, Chihaya Adachi, Hideyuki Murata). It can be used to form display devices and lighting devices.

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 as long as the gist of the present invention is not exceeded. The values of various conditions and evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable ranges are the above-mentioned upper limit or lower limit values and the following. It may be in the range specified by the value of Examples or the combination of the values of Examples.

In the present specification, Me means methyl group, Et means ethyl group, Bu means n- butyl group, Bu ^t denotes a tert- butyl group, Ac is meant acetyl group Ph means a phenyl group, dppf means 1,1'-bis (diphenylphosphino) ferrocene, dba means dibenzylidene acetone, and ampphos means [4- (N, N-dimethylamino). ) Phenyl] di-tert-butylphosphine, THF means tetrahydrofuran.

<Synthesis example of compound 1>
(Synthesis of Intermediate 1)

After adding 10.7 g of 1-bromo-2-naphthoic acid to 100 mL of methanol, 27 mL of concentrated sulfuric acid was added dropwise with stirring at room temperature. The mixture was stirred in an oil bath at 80 ° C. for 4.5 hours. The reaction solution was returned to room temperature, the reaction solution was added little by little to about 300 mL of ice water, and then suction filtration was performed. The filtrate was dissolved in about 100 mL of dichloromethane, magnesium sulfate and white clay were added, and the mixture was stirred at room temperature. By filtering through silica gel and distilling off the solvent, 10.8 g of a white solid of Intermediate 1 was obtained.

(Synthesis of Intermediate 2)

Under a nitrogen atmosphere, 6.14 g of 3-bromodibenzofuran, 7.72 g of bis (pinacolato) diboron, 0.61 g of PdCl ₂ (dppf) CH ₂ Cl ₂ and 12.2 g of potassium acetate were added to 100 mL of 1,4-dioxane (dehydrated). In addition, the mixture was stirred at 90 ° C. for 4.5 hours. The reaction solution was cooled to room temperature and then filtered through silica gel to distill off the solvent. The obtained residue was purified by silica gel column chromatography to obtain 5.99 g of a white solid of Intermediate 2.

(Synthesis of Intermediate 3)

After adding 24 mL of intermediate 1 (5.41 g), intermediate 2 (5.99 g) and 2 mol / L tripotassium phosphate aqueous solution to a mixed solvent of 50 mL of toluene and 20 mL of ethanol, nitrogen substitution was performed with stirring. rice field. Pd _{(PPh 3)} 4 0.45g was added, and stirred for 4.5 hours at 100 ° C.. After cooling the reaction solution to room temperature, the aqueous layer was removed. The solvent of the organic layer was distilled off, and the obtained residue was purified by silica gel column chromatography to obtain 6.65 g of a white solid of Intermediate 3.

(Synthesis of Intermediate 4)

Under a nitrogen atmosphere, 9.9 g of bromobenzene was dissolved in 70 mL of THF (deoxidized), cooled in a dry ice-acetone bath, and stirred at −78 ° C. for 10 minutes. 35 mL of a 1.55 mol / L n-butyllithium / hexane solution was added dropwise so that the internal temperature did not exceed −65 ° C., and the mixture was stirred for 1 hour while cooling in a dry ice-acetone bath. After adding Intermediate 3 (6.3 g) to the mixture, the dry ice-acetone bath was removed and the mixture was stirred at room temperature for 1.5 hours. After about 20 mL of distilled water was added dropwise, dichloromethane and water were added for liquid separation washing, and the organic layer was dried over magnesium sulfate. By filtering and distilling off the solvent under reduced pressure, about 12 g of a crude product containing Intermediate 4 was obtained. Intermediate 4 was used in the next reaction without further purification.

(Synthesis of Intermediate 5)

Approximately 12 g of the crude product containing Intermediate 4 obtained in the above (synthesis of Intermediate 4) was dissolved in 50 mL of acetic acid, 1 mL of concentrated sulfuric acid was added dropwise with stirring at room temperature, and the mixture was stirred at 80 ° C. for 1 hour. After cooling the reaction solution to room temperature, 50 mL of ethanol was added, suction filtration was performed, and the filtrate was washed with ethanol and methanol. The obtained crude product was recrystallized from a mixed solvent of dichloromethane and methanol to obtain 6.05 g of a white solid of Intermediate 5.

(Synthesis of Intermediate 6)

Intermediate 5 (6.05 g) was dissolved in 220 mL of dichloromethane, and a mixed solution of 1.8 mL of bromine and 20 mL of dichloromethane was added dropwise at room temperature while stirring at room temperature, and then the mixture was stirred at room temperature for 15 minutes. After adding an aqueous sodium sulfite solution to the reaction solution until the bromine color disappeared, methanol was added and suction filtration was performed. The filtrate was washed with methanol, water, and methanol in this order and dried to obtain 6.08 g of a white solid of Intermediate 6.

(Synthesis of Intermediate 7)

Intermediate 6 (4.00 g) was dissolved in 900 mL of dichloromethane, and a mixed solution of 0.8 mL of bromine and 10 mL of dichloromethane was added dropwise at room temperature while stirring at room temperature, and then the mixture was stirred at room temperature for 30 minutes. 50 mL of acetic acid and 0.5 g of iron powder were added to the reaction solution, and the mixture was stirred at room temperature for 10 hours. Aqueous sodium sulfite solution was added until the bromine color disappeared, and then the aqueous layer was removed.

The solvent of the organic layer was distilled off, and the obtained residue was suspended and washed with a mixed solvent of dichloromethane and methanol. After suction filtration, the filtrate was suspended and washed with a mixed solvent of ethyl acetate and ethanol. By suction filtration and drying the filtrate, about 3.5 g of a crude product containing Intermediate 7 was obtained. Intermediate 7 was used in the next reaction without further purification.

(Synthesis of Intermediate 8)

Under a nitrogen atmosphere, _{0.52 g of Pd 2} (dba) ₃ CHCl ₃ and 1.1 g of dppf were dissolved in 5 mL of toluene (deoxygenated), and the mixture was stirred at 60 ° C. to prepare a catalytic solution. Separately, under a nitrogen atmosphere, 10.0 g of 4-bromodibenzofuran, 8.7 g of p-octylaniline, and 7.8 g of sodium-t-butoxide were dissolved in 100 mL of toluene (deoxidized) and stirred at 60 ° C., and the above catalyst was used. The solution was added with a syringe and stirred at 100 ° C. for 1 hour.

The reaction solution was cooled to room temperature, the solvent was distilled off, and the obtained residue was purified by silica gel column chromatography to obtain 14.1 g of a white solid of intermediate 8.

(Synthesis of Compound 1)

Under a nitrogen atmosphere, _{90 mg of Pd 2} (dba) ₃ CHCl ₃ and 200 mg of amphos were dissolved in 5 mL of toluene (deoxygenated), and the mixture was stirred at 60 ° C. to prepare a catalytic solution. Separately, under a nitrogen atmosphere, intermediate 7 (1.5 g), intermediate 8 (3.0 g), and 1.2 g of sodium-t-butoxide were dissolved in 50 mL of toluene (deoxidized) and stirred at 60 ° C. above. The catalyst solution of No. 1 was added with a syringe, and the mixture was stirred at 100 ° C. for 1.5 hours. The reaction solution was cooled to room temperature, activated clay and toluene were added, and the mixture was stirred at room temperature for 10 minutes. After suction filtration, the solvent of the filtrate was distilled off. The obtained residue was purified by silica gel column chromatography to obtain 0.66 g of Compound 1.

<Synthesis example of Comparative Compound 1>
(Synthesis of Intermediate 9)

Add intermediate 1 (1.7 g), 2.3 g of 9,9-diphenylfluorene-2-boronic acid and 10 mL of a 2 mol / L tripotassium phosphate aqueous solution to a mixed solvent of 50 mL of toluene and 20 mL of ethanol, and then stir. While nitrogen substitution was performed. Pd _{(PPh 3)} 4 0.25g was added, and stirred for 8 hours at 100 ° C.. After cooling the reaction solution to room temperature, the aqueous layer was removed. The solvent of the organic layer was distilled off, and the obtained residue was purified by silica gel column chromatography to obtain 3.1 g of a white solid of Intermediate 9.

(Synthesis of Intermediate 10)

Under a nitrogen atmosphere, 3.3 g of bromobenzene was dissolved in 15 mL of THF (deoxygenated), cooled in a dry ice-acetone bath, and stirred at −78 ° C. for 10 minutes. 12 mL of a 1.55 mol / L n-butyllithium / hexane solution was added dropwise so that the internal temperature did not exceed −65 ° C., and the mixture was stirred for 1 hour while cooling in a dry ice-acetone bath. After adding Intermediate 9 (3.1 g) thereto, the dry ice-acetone bath was removed and the mixture was stirred at room temperature for 2 hours. After about 10 mL of distilled water was added dropwise, dichloromethane and water were added for liquid separation washing, and the organic layer was dried over magnesium sulfate. By filtering and distilling off the solvent under reduced pressure, about 4 g of a crude product containing Intermediate 10 was obtained. Intermediate 10 was used in the next reaction without further purification.

(Synthesis of Intermediate 11)

Approximately 4 g of the crude product containing Intermediate 10 obtained in the above (synthesis of Intermediate 10) was added to a mixed solvent of 50 mL of acetic acid and 50 mL of THF, 5 mL of concentrated sulfuric acid was added dropwise with stirring at room temperature, and then oil at 100 ° C. was added. The mixture was refluxed and stirred in a bath for 3 hours. After cooling the reaction solution to room temperature, 100 mL of methanol was added and suction filtration was performed. The filtrate was washed with methanol and dried to obtain 3.3 g of a white solid of Intermediate 11.

(Synthesis of Intermediate 12)

Intermediate 11 (1.0 g) was dissolved in 300 mL of chloroform and 70 mL of acetic acid was added. After adding 2.0 g of benzyltrimethylammonium tribromide and 1.9 g of zinc chloride with stirring at room temperature, the mixture was stirred at room temperature for 6.5 hours and at 70 ° C. for 6.5 hours. After cooling the reaction solution to room temperature, the reaction solution was concentrated under reduced pressure, and methanol was added. The resulting precipitate was suction filtered. The filtrate was washed with methanol and dried to obtain 1.2 g of a pale yellow solid of Intermediate 12.

(Synthesis of Comparative Compound 1)

Under a nitrogen atmosphere, _{47 mg of Pd 2} (dba) ₃ CHCl ₃ 47 mg and 110 mg of amphos were dissolved in 5 mL of toluene (deoxygenated), and the mixture was stirred at 60 ° C. to prepare a catalytic solution. Separately, under a nitrogen atmosphere, intermediate 12 (1.2 g), 0.60 g of diphenylamine, and 0.66 g of sodium-t-butoxide were dissolved in 300 mL of toluene (deoxidized) and stirred at 60 ° C. to prepare the above catalyst solution. It was added with a syringe and stirred at 100 ° C. for 3 hours. The reaction solution was cooled to room temperature, activated clay was added, and the mixture was stirred at room temperature for 10 minutes. After suction filtration, the solvent of the filtrate was distilled off. The obtained residue was purified by silica gel column chromatography, and the obtained yellow solid was washed with a mixed solvent of ethyl acetate and ethanol and dried to obtain 0.71 g of Comparative Compound 1.

<Manufacturing and evaluation of organic electroluminescent devices>
Hereinafter, the results of manufacturing an organic electroluminescent device using the above compound and evaluating its performance will be shown.

[Example 1]
An organic electroluminescent device was manufactured by the following method.
A transparent conductive film of indium tin oxide (ITO) deposited on a glass substrate to a thickness of 50 nm (manufactured by Sanyo Vacuum Co., Ltd., sputter-deposited product) is 2 mm wide using ordinary photolithography technology and hydrochloric acid etching. The stripes were patterned to form an anode. The substrate on which the ITO pattern is formed is washed in the order of ultrasonic cleaning with an aqueous surfactant solution, water washing with ultrapure water, ultrasonic cleaning with ultrapure water, and water washing with ultrapure water, and then dried with compressed air. Finally, UV ozone cleaning was performed.

As the composition for forming the hole injection layer, 3.0% by mass of the hole-transporting polymer compound having a repeating structure represented by the following formula (P-1) and the composition represented by the following formula (HI-1). A composition was prepared in which 0.6% by mass of an oxidizing agent was dissolved in ethyl benzoate.

This solution was spin-coated on the substrate in the atmosphere and dried on an atmospheric hot plate at 240 ° C. for 30 minutes to form a uniform thin film having a film thickness of 40 nm to form a hole injection layer.

Next, 100 parts by mass of the charge-transporting polymer compound having the following structural formula (HT-1) was dissolved in cyclohexylbenzene to prepare a 2.0% by mass solution.

This solution is spin-coated on a substrate coated with the hole injection layer in a nitrogen glove box, dried on a hot plate in the nitrogen glove box at 230 ° C. for 30 minutes, and a uniform thin film having a film thickness of 25 nm. Was formed to form a hole transport layer.

Subsequently, as the material of the light emitting layer, 95 parts by mass of the compound represented by the following structural formula (H-1) and 5 parts by mass of the compound represented by the following structural formula (D-1) were weighed and cyclohexylbenzene was used. To prepare a 4.0% by mass solution. Here, the compound represented by the following structural formula (D-1) is the above-mentioned compound 1.

This solution was spin-coated on a substrate coated with the hole transport layer in a nitrogen glove box, dried on a hot plate in the nitrogen glove box at 120 ° C. for 20 minutes, and a uniform thin film having a film thickness of 40 nm. Was formed to form a light emitting layer.

The substrate on which the film was formed up to the light emitting layer was installed in a vacuum vapor deposition apparatus, and the inside of the apparatus was exhausted until it became ^{2 × 10 -4 Pa or less.}

Next, the compound represented by the following structural formula (HB-1) and 8-hydroxyquinolinolatrium were placed on the light emitting layer at a film thickness ratio of 2: 3 by vacuum deposition at a rate of 1 Å / sec. Co-deposited to form a hole blocking layer with a film thickness of 30 nm.

Subsequently, a striped shadow mask having a width of 2 mm was brought into close contact with the substrate so as to be orthogonal to the ITO stripe of the anode as a mask for cathode vapor deposition, and installed in another vacuum vapor deposition apparatus. Then, aluminum was heated by a molybdenum boat to form an aluminum layer having a film thickness of 80 nm at a vapor deposition rate of 1 to 8.6 Å / sec to form a cathode. As described above, an organic electroluminescent device having a light emitting area portion having a size of 2 mm × 2 mm was obtained.

[Comparative Example 1]
Organic electroluminescence is carried out in the same manner as in Example 1 except that the following structural formula (D-2) is used instead of the compound represented by the above structural formula (D-1) as the material of the light emitting layer. The device was manufactured. Here, the compound represented by the following structural formula (D-2) is Comparative Compound 1.

[Evaluation of organic electroluminescent device]
The current efficiency (cd / A) of the obtained organic electroluminescent devices of Example 1 and Comparative Example 1 ^{when light was emitted at a brightness of 1000 cd / m 2 was measured.} Table 1 below shows the relative values of the current efficiencies of the organic electroluminescent device of Comparative Example 1 (hereinafter referred to as "relative current efficiency") when the current efficiency of the organic electroluminescent device of Example 1 is 100. bottom.

Further, the obtained organic electroluminescent devices of Example 1 and Comparative Example 1 ^{were driven at 20 mA / cm 2} , and the 20% luminance attenuation lifetime (LT80) was measured. Obtaining a relative value of the 20% luminance attenuation lifetime of the organic electroluminescent device of Comparative Example 1 (hereinafter referred to as "relative attenuation lifetime") when the 20% attenuation lifetime of the organic electroluminescent device of Example 1 is 100. , Table 1.

As shown in the results in Table 1, it was found that the organic electroluminescent device of the present invention has improved current efficiency and a 20% luminance attenuation life as compared with the organic electroluminescent device of the comparative example.

1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electroluminescent device

Claims (7)

An aromatic diamine derivative represented by the following formula (1).

[In formula (1), R ¹ and R ² each independently consist of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group consisting of an aromatic hydrocarbon group and an aromatic heterocyclic group. A group in which a plurality of selected at least one group is linked directly or via a linking group. R ¹ and R ² may be combined with each other to form a ring. R ¹ and R ² may have a substituent. Am ¹ is a substituent represented by the following general formula (2a). Am ² is a substituent represented by the following general formula (2b). Y is a heteroatom.

In the formulas (2a) and (2b), the asterics (*) represent the combination with the formula (1). Ar ^{1 to} Ar ⁴ are independently directly derived from at least one group selected from the group consisting of an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Alternatively, it is a group in which a plurality of groups are linked via a linking group. Ar ¹ and Ar ² may be combined with each other to form a ring. Ar ³ and Ar ⁴ may be combined with each other to form a ring. Ar ^{1 to} Ar ⁴ may have a substituent. ] The aromatic diamine derivative according to claim 1, wherein the formula (1) is the following formula (3).

[In the formula (3), R ¹ , R ² , Am ¹ and Am ² are the same as those in the formula (1). ] ^{The aromatic diamine derivative according to claim 1 or 2} , wherein Ar 2 is a substituent represented by the following formula (4a).

[In the formula (4a), the asterics (*) represent the bond with the nitrogen atom in the formula (2a), and X ₁ is an oxygen atom, a sulfur atom, N-R ⁴¹ , or C (R ⁵¹ ) (R). ⁶¹ ) is represented. In R ³¹ , at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group has a direct or linking group. Represents a plurality of groups linked via a group. R ⁴¹ , R ⁵¹ , and R ⁶¹ are independently selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Represents a group in which a plurality of at least one group to be linked is directly or via a linking group. n represents an integer from 0 to 7. R ³¹ , R ⁴¹ , R ⁵¹ , and R ⁶¹ may have a substituent. ] The aromatic diamine derivative according to any one of claims 1 to 3, wherein Ar ^{4 is a substituent represented by the following formula (4b).}

[In the formula (4b), the asterix (*) represents the bond with the nitrogen atom in the formula (2b), and X ₂ is an oxygen atom, a sulfur atom, N-R ⁴² , or C (R ⁵² ) (R). ⁶² ). In R ³² , at least one group selected from the group consisting of an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group has a direct or linking group. Represents a plurality of groups linked via a group. R ⁴² , R ⁵² , and R ⁶² are independently selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or an aromatic hydrocarbon group and an aromatic heterocyclic group. Represents a group in which a plurality of at least one group to be linked is directly or via a linking group. m represents an integer from 0 to 7. R ³² , R ⁴² , R ⁵² , and R ⁶² may have a substituent. ] A light emitting material for an organic electroluminescent device containing the aromatic diamine derivative according to any one of claims 1 to 4. A composition for an OLED containing two or more kinds of a light emitting material for an organic electric field light emitting device according to claim 5 and a solvent having a boiling point of 150 ° C. or higher. An organic electroluminescent device including the light emitting material for the organic electroluminescent device according to claim 5.

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