WO2011125919A1

WO2011125919A1 - Novel triarylamines and use thereof

Info

Publication number: WO2011125919A1
Application number: PCT/JP2011/058379
Authority: WO
Inventors: 英樹則定; 信隆赤司
Original assignee: バンドー化学株式会社
Priority date: 2010-04-09
Filing date: 2011-03-25
Publication date: 2011-10-13
Also published as: TW201139340A

Abstract

Disclosed are triarylamines represented by general formula (I). (In the formula, A₁ to A₃ each represents an optionally substituted phenylene group; X₁ to X₃ each independently represents a (substituted) phenyl group, and at least one of the (substituted) phenyl groups has, as a substituent, at least one hydroxyl group or at least one aliphatic hydrocarbon group that has a hydroxyl group.)

Description

Novel triarylamines and their use

The present invention relates to novel triarylamines and their use, and more specifically to, for example, an organic electroluminescence device having at least one functional layer containing the triarylamines.

In recent years, organic electroluminescence elements have low voltage direct current drive, high efficiency, high luminance, and can be thinned, so that they are being put to practical use as display devices in addition to backlights and illumination devices.
This organic electroluminescence element typically has a transparent substrate, for example, a glass substrate on which an anode made of a transparent electrode such as an ITO film (indium oxide-tin oxide film) is laminated. In any case, a hole injection layer, a hole transport layer and a light emitting layer, which are functional layers, and a cathode made of a metal electrode are laminated in this order, and the anode and the cathode are connected to an external power source. It is connected. In addition, organic electroluminescence elements having various layer configurations including electrodes are known (see, for example, Patent Document 1).
Conventionally, in the production of such an organic electroluminescence device, for example, the functional layer of a hole injection layer or a hole transport layer is often a low molecular weight organic compound that can form an amorphous film by itself. (See, for example, Patent Documents 2 and 3). However, in general, in order to form a functional layer by such a vapor deposition method, an expensive vapor deposition apparatus is required, and it is difficult to form a large-area layer, and productivity is poor.
Furthermore, in general, low molecular weight organic compounds that can themselves form amorphous films are soluble in many organic solvents, and therefore, when such low molecular weight organic compounds are vacuum deposited to form functional layers, many In this case, if a layer is formed by further applying a solution containing an organic solvent thereon, the functional layer may be dissolved to impair its performance.
Therefore, in recent years, the development of low molecular weight organic compounds and high molecular weight organic polymers that have functions as hole injecting agents and hole transporting agents and that can be dissolved in polar solvents such as water, alcohol, and mixed solvents thereof has been promoted. It has been. For example, a polymer composed of 3,4-polyethylenedioxythiophene (PEDOT), which typically functions as a hole transporting agent and dissolves in water, typically having polystyrene sulfonic acid (PSS) as a dopant. A mixture is known (see Patent Document 4), but it is difficult to say that its performance as a hole transporting agent is sufficient.

JP-A-6-1972 JP 2001-335543 A Japanese Patent Laid-Open No. 2006-22052 JP 2008-031496 A

The present invention has been made to solve the above-described problems in conventional organic electroluminescence devices, and belongs to a so-called starburst compound, but has at least one hydroxyl group or at least one hydroxyl group in the molecule. Application method using a solution having an aliphatic hydrocarbon group and dissolved in a polar solvent such as an aliphatic alcohol such as 1-butanol or an aromatic alcohol such as benzyl alcohol. A novel triarylamine capable of forming a functional layer consisting of a thin film, and at least one functional layer, preferably a hole transporting and / or injecting layer, formed by a coating method, for example. However, the aim is to provide an organic electroluminescence device having high performance. To.

According to the invention, the general formula (I)

(In the formula, A ₁ to A ₃ are each independently a phenylene group which may have a substituent, and X ₁ to X ₃ are each independently a formula (II)

Wherein R ₁ to R ₅ are each independently an aliphatic carbon having a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, a hydroxyl group, or at least one hydroxyl group. A hydrogen group (hereinafter simply referred to as a hydroxy hydrocarbon group for the sake of simplicity), m, n and p are each independently 0, 1 or 2.)
In at least one of X ₁ to X ₃ , at least one of R ₁ to R ₅ is a hydroxyl group or a hydroxy hydrocarbon group. )
The triarylamine represented by these is provided.
Preferred triarylamines according to the invention are those of the general formula (I)

Wherein R ₁ to R ₅ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, a hydroxyl group or a hydroxy hydrocarbon group, and m, n And p are each independently 0, 1 or 2.)
In any of X ₁ to X ₃ , at least one of R ₁ to R ₅ is a hydroxyl group or a hydroxy hydrocarbon group. )
It is represented by
According to a preferred embodiment of the present invention, in the general formula (I), the phenylene groups A ₁ to A ₃ are each independently a p-phenylene group which may have a substituent, and the general formula (II) R ₁ to R ₅ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, preferably a methyl group having 1 to 4 carbon atoms, an ethyl group, a propyl group, or A butyl group, a cycloalkyl group having 5 or 6 carbon atoms, preferably a cyclohexyl group, a hydroxyl group or a hydroxy hydrocarbon group, and m, n and p are each independently 0, 1 or 2.
That is, in the triarylamines represented by the general formula (I), the phenyl groups X ₁ to X ₃ are each independently a phenyl group having a substituent or not having a substituent. X ₁ to X ₃ may be each referred to as a (substituted) phenyl group.
Further, according to the present invention, an organic electronic material containing the triarylamines, an organic electroluminescent device having at least one functional layer containing the organic electronic material, Or the organic electroluminescent element used as an injection agent is provided.

The triarylamines according to the present invention function as an organic electronic material, and in particular, have an excellent function as a hole injection and / or transport agent and have at least one hydroxyl group or hydroxyhydrocarbon group in the molecule. It does not dissolve in non-polar solvents, but dissolves in polar solvents such as alcohols. Therefore, the triarylamines according to the present invention are dissolved in a polar solvent to form a solution, and a thin film or a functional layer can be formed on an appropriate base material by applying the solution. For example, according to a preferred embodiment, in the production of an organic electroluminescence element, a hole injection and / or transport layer and other functional layers can be formed by a coating method.

FIG. 1 is a cross-sectional view showing a preferred example of an organic electroluminescence device according to the present invention.
FIG. 2 is an FT-IR spectrum of tris (4′-hydroxybiphenylyl) amine (compound of formula (15)) according to the present invention.
FIG. 3 is an FT-IR spectrum of tris (3′-hydroxybiphenylyl) amine (compound of formula (16)) according to the present invention.
FIG. 4 is an FT-IR spectrum of tris (4′-hydroxy-3 ′, 5′-dimethylbiphenylyl) amine (compound of formula (17)) according to the present invention.
FIG. 5 is a DSC chart of tris (4′-hydroxy-3 ′, 5′-dimethylbiphenylyl) amine (compound of formula (17)) according to the present invention.
FIG. 6 is a TG / DTA chart of tris (4′-hydroxy-3 ′, 5′-dimethylbiphenylyl) amine (compound of formula (17)) according to the present invention.
FIG. 7 is an FT-IR spectrum of tris (4′-hydroxymethylbiphenylyl) amine (compound of formula (18)) according to the present invention.
FIG. 8 is a DSC chart of tris (4′-hydroxymethylbiphenylyl) amine (compound of formula (18)) according to the present invention.
FIG. 9 is a TG / DTA chart of tris (4′-hydroxymethylbiphenylyl) amine (compound of formula (18)) according to the present invention.
FIG. 10 is an FT-IR spectrum of tris (3′-hydroxymethylbiphenylyl) amine (compound of formula (19)) according to the present invention.
FIG. 11j is a DSC chart of tris (3′-hydroxymethylbiphenylyl) amine (compound of formula (19)) according to the present invention.
FIG. 12 is a TG / DTA chart of tris (3′-hydroxymethylbiphenylyl) amine (compound of formula (19)) according to the present invention.
FIG. 13 is an FT-IR spectrum of tris (4 ″ -hydroxymethylterphenylyl) amine (compound of formula (32)) according to the present invention.
FIG. 14 is a DSC chart of tris (4 ″ -hydroxymethylterphenylyl) amine (compound of formula (32)) according to the present invention.
FIG. 15 is a TG / DTA chart of tris (4 ″ -hydroxymethylterphenylyl) amine (compound of formula (32)) according to the present invention.
FIG. 16 is an FT-IR spectrum of bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine (compound of formula (8)) according to the present invention.
FIG. 17 is a DSC chart of bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine (compound of formula (8)) according to the present invention.
FIG. 18 is a TG / DTA chart of bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine (compound of formula (8)) according to the present invention.
FIG. 19 is an FT-IR spectrum of bis (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine (compound of formula (50)) according to the present invention.
FIG. 20 is a DSC chart of bis (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine (compound of formula (50)) according to the present invention.

The novel triarylamines according to the invention have the general formula (I)

Wherein R ₁ to R ₅ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, a hydroxyl group or a hydroxy hydrocarbon group, and m, n And p are each independently 0, 1 or 2.)
In at least one of X ₁ to X ₃ , at least one of R ₁ to R ₅ is a hydroxyl group or a hydroxy hydrocarbon group. )
It is represented by
Such triarylamines have at least one hydroxyl group or hydroxy hydrocarbon group in the molecule.
In the triarylamines represented by the above general formula (I), the substituents that the phenylene groups A ₁ to A ₃ may have are not particularly limited, but examples thereof include a hydroxyl group and a hydroxyl group. And an aliphatic hydrocarbon group, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, and the like.
The aliphatic hydrocarbon group having the hydroxyl group may be the same as the hydroxy hydrocarbon group described later. Accordingly, preferred specific examples include, for example, hydroxymethyl group, hydroxyethyl group, hydroxypropyl group, 1-methyl- Examples thereof include a 1-hydroxyethyl group and a 1,2-dihydroxyethyl group.
As said alkyl group, a methyl group, an ethyl group, a propyl group, a butyl group etc. can be mentioned, for example. The alkyl group having 3 or more carbon atoms may be linear or branched. Moreover, as said cycloalkyl group, a cyclohexyl group can be mentioned, for example.
In the triarylamines represented by the general formula (I), the phenylene groups A ₁ to A ₃ are preferably p-phenylene groups which may each independently have a substituent. M, n, and p that define the number of p-phenylene groups are each independently 0, 1, or 2, and when m, n, or p is 0, X ₁ , X _2, or X ₃ are each a molecule (Substituted) phenyl group directly bonded to the central nitrogen atom.
That is, as described above, in the triarylamines represented by the general formula (I), the (substituted) phenyl groups X ₁ to X ₃ each independently have a substituent or a phenyl having no substituent. It is a group.
On the other hand, m, when n or p is _1, X 1, _{X 2} or _{X 3} together with _A 1, _{A 2} or _{A 3} each forms a (substituted) biphenylyl group, m, n or p is 2 when it _is, _X _1, X ₂ or _{X 3} forms a (substituted) terphenylyl group together with _a 1, _{a 2} or _{a 3,} respectively.
Furthermore, in the phenyl group represented by the general formula (II), when R ₁ to R ₅ are each independently an alkyl group having 1 to 6 carbon atoms, specific examples of the alkyl group include, for example, methyl, An ethyl, propyl, butyl, pentyl or hexyl group can be mentioned, and an alkyl group having 3 or more carbon atoms may be linear or branched. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, and specific examples of such an alkyl group include methyl, ethyl, propyl, and butyl groups. The alkyl group having 3 or more carbon atoms may be linear or branched. When R ₁ to R ₅ are each independently a cycloalkyl group, the cycloalkyl group is a cyclopentyl or cyclohexyl group, and preferably a cyclohexyl group.
According to the present invention, in the phenyl group represented by the general formula (II), when at least one of R ₁ to R ₅ is a hydroxyl group or a hydroxy hydrocarbon group, the phenyl of the hydroxyl group or hydroxy hydrocarbon group The bonding position in the group is not particularly limited, and may be any o-, m-, or p-position with respect to the bonding position of the phenylene group A ₁ , A _2, or A ₃ .
In the present invention, in the general formula (II), when at least one of R ₁ to R ₅ is an aliphatic hydrocarbon group having at least one hydroxyl group, that is, a hydroxy hydrocarbon group, the hydroxy hydrocarbon group is Preferably, the general formula (III)

(In the formula, R is an (h + 1) -valent aliphatic hydrocarbon group, and h is 1, 2 or 3.)
It is represented by
Therefore, as a preferable specific example of such a hydroxy hydrocarbon group, for example,

Etc.
In the present invention, the hydroxy hydrocarbon group is not limited to the above examples, but preferred examples thereof include hydroxymethyl group (III-1), hydroxyethyl group (III-2), and hydroxy. A propyl group (III-3), a 1-methyl-1-hydroxyethyl group (III-5), a 1,2-dihydroxyethyl group (III-8) and the like can be mentioned. Preferred triarylamines according to the invention are those of the general formula (I)

Wherein R ₁ to R ₅ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, a hydroxyl group or a hydroxy hydrocarbon group, and m, n And p are each independently 0, 1 or 2.)
In any of X ₁ to X ₃ , at least one of R ₁ to R ₅ is a hydroxyl group or a hydroxy hydrocarbon group. )
It is represented by
Such preferred triarylamines according to the present invention are the illustrated triarylamines according to the present invention, that is, at least one of X ₁ to X _{3 in} the general formula (I), R ₁ to R ₅ Compared to triarylamines in which at least one is a hydroxyl group or a hydroxy hydrocarbon group, in any _one of X ₁ to X _{3 in} the general formula (I), at least one of R ₁ to R ₅ is a hydroxyl group or The same except that it is a hydroxy hydrocarbon group.
Accordingly, in the preferred triarylamines according to the present invention, the phenylene groups A ₁ to A ₃ , the substituents that these phenylene groups may have, and the R ₁ to R that the phenyl group represented by the above general formula (I) has Specific examples when ₅ is independently an alkyl group having 1 to 6 carbon atoms, and when the phenyl group represented by the above general formula (I) has at least one hydroxyl group or hydroxy hydrocarbon group, the hydroxyl group The bonding position of the group or the hydroxy hydrocarbon group, when at least one of R ₁ to R ₅ is an aliphatic hydrocarbon group having at least one hydroxyl group, including the specific examples and the like, Since they are the same, repeated description here is omitted.
Most preferred triarylamines according to the present invention are the above preferred triarylamines, wherein (a) m is 0 and n and p are both 1 or 2, or (b) m, n and p Are all 1, or (c) m, n, and p are all 2.
The triarylamines according to the present invention can be obtained, for example, as follows. First, triarylamines having three hydroxyl groups or hydroxy hydrocarbon groups in the molecule can be obtained, for example, as shown in Scheme 1. In the following scheme 1, X is, for example, a halogen atom such as an iodine atom or a bromine atom, and the same applies to the following schemes 2 and 3.

That is, 1 mol part of tris (4-halogenated phenyl) amine (A) and 3 mol part of phenylboronic acid (B1) in which any _one of R ₁ to R ₅ is a hydroxyl group or a hydroxy hydrocarbon group are mixed with alcohol / water. It can obtain as a compound (C) by making it react under heating using a base and a palladium catalyst in a mixed solvent.
Triarylamines having one hydroxyl group or hydroxyhydrocarbon group in the molecule can be obtained, for example, as shown in Scheme 2.

That is, 1 mol part of tris (4-halogenated phenyl) amine (A) and 2 mol parts of phenylboronic acid (B2) in which none of R ′ ₁ to R ′ ₅ is a hydroxyl group or a hydroxy hydrocarbon group. Compound D is obtained by reaction under heating with a base and a palladium catalyst in an alcohol / water mixed solvent, and then any _one of R ₁ to R ₅ is a hydroxyl group or a hydroxy hydrocarbon in 1 mol part of Compound D. Compound E can be obtained by reacting 1 mol part of phenylboronic acid (B1) as a group in the same manner.
Similarly, triarylamines having two hydroxyl groups or hydroxy hydrocarbon groups in the molecule can be obtained, for example, as shown in Scheme 3 below.

That is, 1 mol part of tris (4-halogenated phenyl) amine (A) and 1 mol part of phenylboronic acid (B2) in which none of R ′ ₁ to R ′ ₅ is a hydroxyl group or a hydroxy hydrocarbon group. Compound F is obtained by reaction under heating with a base and a palladium catalyst in an alcohol / water mixed solvent, and then any _one of R ₁ to R ₅ is a hydroxyl group or a hydroxy hydrocarbon in ₁ mol part of compound F The compound G can be obtained by reacting 2 mol parts of phenylboronic acid (B1) as a group in the same manner.
Triarylamines having 4, 5, 6 or more hydroxyl or hydroxy hydrocarbon groups in the molecule may also be one, two or three hydroxyl groups or hydroxy hydrocarbons in the molecule. It is obvious that the above schemes 1 to 3 showing the method for producing a triarylamine having a group can be easily obtained by appropriately changing the schemes.
Accordingly, specific examples of preferable triarylamines according to the present invention include, for example, the following formula (1):

Compound (1) represented by the following formula (2)

Compound (2) represented by the following formula (3)

Compound (3) represented by the following formula (4)

Compound (4) represented by the following formula (5)

Compound (5) represented by the following formula (6)

(6) represented by the following formula (7)

Compound (7) represented by the following formula (8)

Compound (8) represented by the following formula (9)

Compound (9) represented by the following formula (10)

Compound (10) represented by the following formula (11)

Compound (11) represented by the following formula (12)

The compound (12) represented by the following formula (13)

Compound (13) represented by the following formula (14)

Compound (14) represented by the following formula (15)

Compound (15) represented by the following formula (16)

Compound (16) represented by the following formula (17)

Compound (17) represented by the following formula (18)

Compound (18) represented by the following formula (19)

Compound (19) represented by the following formula (20)

The compound (20) represented by the following formula (21)

Compound (21) represented by the following formula (22)

Compound (22) represented by the following formula (23)

Compound (23) represented by the following formula (24)

Compound (24) represented by the following formula (25)

Compound (25) represented by the following formula (26)

Compound (26) represented by the following formula (27)

A compound represented by formula (27):

A compound represented by formula (28):

Compound (29) represented by the following formula (30)

The compound (30) represented by the following formula (31)

Compound (31) represented by the following formula (32)

Compound (32) represented by the following formula (33)

Compound (33) represented by formula (34)

(34) represented by the following formula (35)

Compound (35) represented by the following formula (36)

(36) represented by the following formula (37)

Compound (37) represented by formula (38):

A compound represented by formula (38):

Compound (39) represented by the following formula (40)

Compound (40) represented by the following formula (41)

Compound (41) represented by formula (42)

A compound represented by formula (42):

(43) represented by the following formula (44)

(44) represented by the following formula (45)

Compound (45) represented by the following formula (46)

Compound (46) represented by the following formula (47)

Compound (47) represented by the following formula (48)

Compound (48) represented by the following formula (49)

Compound (49) represented by the following formula (50)

A compound represented by formula (51)

The compound etc. which are represented by these can be mentioned.
The triarylamines according to the present invention have at least one hydroxyl group or hydroxyhydrocarbon group in the molecule, and according to a preferred embodiment, have a plurality of hydroxyl groups and / or hydroxyhydrocarbon groups in the molecule. For example, it dissolves in a polar solvent such as an aliphatic alcohol such as 1-butanol or an aromatic alcohol such as benzyl alcohol, but does not dissolve in a nonpolar solvent such as toluene. Furthermore, the triarylamines according to the present invention are useful as organic electronic materials, particularly as an organic electronic material for forming a hole injection layer and / or a transport layer, which is a functional layer in an organic electroluminescence device, and a light emitting layer. In particular, it can be suitably used as a hole injecting agent and / or a transporting agent for forming a hole injecting layer and / or a transporting layer.
Therefore, for example, in the production of an organic electroluminescence device, a solution obtained by dissolving the triarylamines according to the present invention in a polar solvent is applied onto an appropriate substrate and dried, so that the hole injection layer and / or A transport layer can be formed. However, the use of the triarylamines according to the present invention is not limited to the above hole injecting agent and / or transporting agent.
As shown in FIG. 1 as a preferred example of the organic electroluminescence device according to the present invention, for example, a transparent anode 2 made of ITO is closely adhered and supported on a transparent substrate 1 such as glass. A hole injection layer 3a, a hole transport layer 3b, a light emitting layer 4, and a cathode 5 made of a metal or a compound thereof are laminated on the anode in this order. The anode and cathode are connected to an external power source 6. Accordingly, in such an organic electroluminescence device, holes are easily injected from the anode through the hole injection layer and the hole transport layer into the light emitting layer, and electrons are injected from the cathode into the light emitting layer, In this light emitting layer, electrons injected from the cathode and holes injected from the anode recombine to generate light, and light emitted from the light emitting layer is emitted to the outside through the transparent electrode (anode) and the transparent substrate. The
Furthermore, in the present invention, in some cases, as described above, an electron transport layer may be laminated between the light emitting layer and the cathode, and in order to prevent excess holes from escaping to the cathode side. In addition, a blocking layer may be provided. Thus, in the present invention, the layer structure of the organic electroluminescence element is not particularly limited.
The organic electroluminescence device according to the present invention has at least one functional layer containing the above-described triarylamines according to the present invention, and preferably the hole injection and / or transport layer is composed of the above-described triarylamines. Includes hole injection and / or transport agents. As described above, since the triarylamines according to the present invention are dissolved in a polar solvent such as alcohol as described above, for example, the alcohol solution is applied on the transparent electrode and dried to form holes. An injection layer can be formed. In some cases, a conventionally known low molecular weight organic compound is vacuum-deposited on a transparent electrode to form a hole injection layer, and then an alcohol solution of the triarylamine according to the present invention is applied thereon. The hole transport layer can be formed by drying. In this case, as described above, the low molecular weight organic compound forming the hole injection layer is usually dissolved in the nonpolar solvent but not in the polar solvent, so that the present invention is formed on the hole injection layer. Even if the alcohol solution of triarylamines is applied, the hole injection layer is not dissolved in the polar solvent.
In the present invention, the film thickness of both the hole injection layer and the hole transport layer is usually in the range of 10 to 200 nm, and preferably in the range of 20 to 100 nm. Of course, a single hole injection transport layer made of the triarylamines according to the present invention can be formed on the transparent electrode.
In this way, for example, using the triarylamines according to the present invention, a hole injection layer is formed on the transparent electrode, and on the positive electrode made of a known hole transport agent according to a conventional method. An organic electroluminescent element can be obtained by laminating a hole transport layer and further laminating a light emitting layer and a cathode thereon. Similarly, an organic electroluminescence device can be obtained by laminating a hole transport layer made of triarylamines according to the present invention on a suitably formed hole injection layer, and further laminating a light emitting layer and a cathode thereon. be able to.
The organic electroluminescent device according to the present invention has at least one layer comprising the triarylamines according to the present invention, and preferably has a hole injection and / or transport layer comprising the triarylamines according to the present invention. Yes. However, such at least one functional layer comprising the triarylamines according to the invention, preferably a layer other than a hole injection and / or transport layer comprising the triarylamines according to the invention, ie a transparent substrate, a book As other layers to be combined with the above functional layer according to the invention, for example, a normal hole injection and / or transport layer, an anode, a light emitting layer, an electron transport layer and an electrode, those conventionally known are appropriately used. A transparent electrode made of indium oxide-tin oxide (ITO) is preferably used as the anode, and a single metal such as aluminum, magnesium, indium, silver, or an alloy thereof such as an Al—Mg alloy, Ag—is used as the cathode. Mg alloy, lithium fluoride or the like is used, and a glass substrate is usually used as the transparent substrate.
For example, as a normal hole transporting agent, conventionally known low molecular weight organic compounds, for example, α-NPD (4,4′-bis (N- (1-naphthyl) -N-phenyl) as described above Amino) biphenyl) and TPD (4,4′-bis (3-methylphenyl) -N-phenylamino) biphenyl are used. Tris (p-terphenyl-4-yl) amine is also used as a hole transporting agent.
As a normal hole injecting agent, copper phthalocyanine or the like is used. The film thickness is usually in the range of 10 to 200 nm, preferably in the range of 20 to 100 nm.
For example, tris (8-quinolinol) aluminum (Alq ₃ ) is used for the organic light emitting layer, and the film thickness is usually in the range of 10 to 200 nm, and preferably in the range of 20 to 100 nm. Further, when the organic electroluminescence element includes an electron transport layer, the film thickness is usually in the range of 10 to 200 nm, and preferably in the range of 20 to 100 nm.
The triarylamines according to the present invention are not limited at all in their applications. In addition to the hole injecting agent, hole transporting agent, and host agent in the light emitting layer in the above-described organic electroluminescence device, for example, in solar cells. It can also be suitably used for charge transport materials in organic semiconductors and electrophotographic devices.
In particular, the triarylamines according to the present invention having an ionization potential in the range of 5.1 to 5.8 eV can be suitably used as a hole injection and / or transport agent in an organic electroluminescence device.

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
Example 1
As shown in the following scheme 4, tris (4′-hydroxybiphenylyl) amine (the compound of the formula (15)) was obtained.

That is, 2.0 g of tris (4-iodophenyl) amine (a), 1.5 g of 4-hydroxyphenylboronic acid (b), 0.007 g of palladium (II) acetate, 0.017 g of triphenylphosphine, sodium carbonate 1. 5 g and 21 mL of a mixed solvent of ethanol / water (volume ratio 2/1) were charged into a 100 mL three-necked flask, heated to 78 ° C. with stirring, and reacted at this temperature with stirring for 9 hours. After completion of the reaction, the resulting reaction mixture was washed with water and purified by silica gel chromatography. The obtained purified product was recrystallized from a mixed solvent of ethanol / water to obtain 0.93 g of the target tris (4′-hydroxybiphenylyl) amine (the compound of the formula (15)).
Elemental analysis value (% by weight):
C H N O
Calculated value 82.90 5.22 2.69 9.20
Measurement 82.77 5.50 2.42 9.21
Infrared absorption spectrum (KBr method):
The FT-IR spectrum of tris (4′-hydroxybiphenylyl) amine is shown in FIG.
Molecular weight by mass spectrometry ((M + 1) / Z): 522
Example 2
2.0 g tris (4-iodophenyl) amine, 1.5 g 3-hydroxyphenylboronic acid, 0.007 g palladium acetate (II), 0.017 g triphenylphosphine, 1.5 g sodium carbonate and ethanol / water (volume ratio) 2/1) 21 mL of a mixed solvent was charged into a 100 mL three-necked flask, heated to 78 ° C. while stirring, and reacted at this temperature with stirring for 6 hours. After completion of the reaction, the resulting reaction mixture was washed with water and purified by silica gel chromatography. The obtained purified product was recrystallized from ethanol to obtain 1.4 g of the target tris (3′-hydroxybiphenylyl) amine (the compound of the formula (16)).
Elemental analysis value (% by weight):
C H N O
Calculated value 82.90 5.22 2.69 9.20
Measurement 82.88 5.33 2.41 9.38
Infrared absorption spectrum (KBr method):
The FT-IR spectrum of tris (3′-hydroxybiphenylyl) amine is shown in FIG.
Molecular weight by mass spectrometry ((M + 1) / Z): 522
Example 3
As shown in the following scheme 5, tris (4′-hydroxy-3 ′, 5′-dimethylbiphenylyl) amine (the compound of the formula (17)) was obtained.

That is, 2.0 g of tris (4-iodophenyl) amine (a), 2,6-dimethyl-4 (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) phenol ( b1) 2.6 g, palladium acetate (II) 0.007 g, triphenylphosphine 0.017 g, sodium carbonate 1.5 g and ethanol / water (volume ratio 2/1) mixed solvent 21 mL were charged into a 100 mL capacity three-necked flask and stirred. The temperature was raised to 78 ° C., and the reaction was carried out at this temperature with stirring for 5 hours. After completion of the reaction, the resulting reaction mixture was washed with water and purified by silica gel chromatography. The purified product obtained was recrystallized from an ethanol / water mixed solvent to obtain 1.1 g of the desired tris (4′-hydroxy-3 ′, 5′-dimethylbiphenylyl) amine (the compound of the formula (17)). Got.
Elemental analysis value (% by weight):
C H N O
Calculated value 83.28 6.49 2.31 7.92
Measurement 82.66 6.77 2.15 8.42
Infrared absorption spectrum (KBr method):
FIG. 4 shows the FT-IR spectrum of tris (4′-hydroxy-3 ′, 5′-dimethylbiphenylyl) amine.
Molecular weight by mass spectrometry ((M + 1) / Z): 606
Differential scanning calorimetry (DSC):
As shown in the DSC chart in FIG. 5, the melting points of tris (4′-hydroxy-3 ′, 5′-dimethylbiphenylyl) amine are 257.2 ° C. and 284.1 ° C., and the glass transition point is 112.3. ° C.
Thermogravimetry / Differential calorimetry (TG / DTA):
As shown in FIG. 6, the decomposition temperature of tris (4′-hydroxy-3 ′, 5′-dimethylbiphenylyl) amine was 476.6 ° C.
Example 4
As shown in the following scheme 6, tris (4′-hydroxymethylbiphenylyl) amine (the compound of the formula (18)) was obtained.

That is, 4.5 g of tris (4-iodophenyl) amine (a), 3.7 g of 4- (hydroxymethyl) phenylboronic acid (b2), 0.016 g of palladium (II) acetate, 0.038 g of triphenylphosphine, carbonic acid 3.5 g of sodium and 49 mL of ethanol / water (volume ratio 2/1) mixed solvent were charged into a 100 mL three-necked flask, heated to 78 ° C. while stirring, and reacted at this temperature with stirring for 4 hours. After completion of the reaction, the resulting reaction mixture was washed with water and purified by silica gel chromatography. The obtained purified product was recrystallized from a mixed solvent of ethanol / hexane to obtain 3.5 g of the target tris (4′-hydroxymethylbiphenylyl) amine (the compound of the formula (18)).
Elemental analysis value (% by weight):
C H N O
Calculated value 83.10 5.90 2.48 8.51
Measured value 83.00 5.97 2.23 8.80
Infrared absorption spectrum (KBr method):
FIG. 7 shows an FT-IR spectrum of tris (4′-hydroxymethylbiphenylyl) amine.
Molecular weight by mass spectrometry ((M + 1) / Z): 564
Differential scanning calorimetry (DSC):
As shown in FIG. 8 of the DSC chart of tris (4′-hydroxymethylbiphenylyl) amine, neither melting point nor glass transition point was observed.
Thermogravimetry / Differential calorimetry (TG / DTA):
As shown in FIG. 9 of the TG / DTA chart of tris (4′-hydroxymethylbiphenylyl) amine, the decomposition temperature was 445.7 ° C.
Ionization potential:
A thin film of tris (4′-hydroxymethylbiphenylyl) amine was formed by spin coating. The ionization potential of this thin film measured with an atmospheric photoelectron spectrometer (AC-1 manufactured by Riken Keiki Co., Ltd.) was 5.53 eV. Therefore, tris (4′-hydroxymethylbiphenylyl) amine can be suitably used as a hole injection and / or transport agent in an organic electroluminescence device.
Solubility test in organic solvents:
Tris (4′-hydroxymethylbiphenylyl) amine (5 mg) was added to toluene, 1-butanol and benzyl alcohol so that each amount would be 2% by weight, and the mixture was heated to 100 ° C. to determine whether it was dissolved. In addition, 4,4 ′, 4 ″ -tris (N-phenyl-N- (m-tolyl) amino) triphenylamine (m— is a typical example of triarylamines having no hydroxyl group in the molecule. MTDATA) (5 mg) was added to toluene, 1-butanol and benzyl alcohol so that each amount would be 2% by weight, and it was examined whether or not it was dissolved by heating to 100 ° C. The results are shown in Table 1.
Example 5
3.0 g of tris (4-iodophenyl) amine, 2.4 g of 3- (hydroxymethyl) phenylboronic acid, 0.011 g of palladium (II) acetate, 0.025 g of triphenylphosphine, 2.3 g of sodium carbonate and ethanol / water (Volume ratio 2/1) 32 mL of a mixed solvent was charged into a 100 mL three-necked flask, heated to 78 ° C. with stirring, and reacted at this temperature with stirring for 10 hours. After completion of the reaction, the resulting reaction mixture was washed with water and purified by silica gel chromatography. The obtained purified product was recrystallized from ethanol to obtain 1.3 g of the target tris (3′-hydroxymethylbiphenylyl) amine (the compound of the formula (19)).
Elemental analysis value (% by weight):
C H N O
Calculated value 83.10 5.90 2.48 8.51
Measurement 82.89 6.06 2.40 8.65
Infrared absorption spectrum (KBr method):
FIG. 10 shows the FT-IR spectrum of tris (3′-hydroxymethylbiphenylyl) amine.
Molecular weight by mass spectrometry ((M + 1) / Z): 564
Differential scanning calorimetry (DSC):
As shown in FIG. 11, the DSC chart of tris (3′-hydroxymethylbiphenylyl) amine had a melting point of 201.2 ° C. and a glass transition point of 78.6 ° C.
Thermogravimetry / Differential calorimetry (TG / DTA):
As shown in FIG. 12, the decomposition temperature of tris (3′-hydroxymethylbiphenylyl) amine was 467.8 ° C.
Ionization potential:
The ionization potential of the tris (3′-hydroxymethylbiphenylyl) amine thin film measured in the same manner as in Example 4 was 5.60 eV. Therefore, tris (3′-hydroxymethylbiphenylyl) amine can be suitably used as a hole injection and / or transport agent in an organic electroluminescence device.
Solubility measurement in organic solvents:
As described above, in the same manner as the tris (4′-hydroxymethylbiphenylyl) amine (the compound of the formula (18)), the tris (3′-hydroxymethylbiphenylyl) amine can be added to an organic solvent. A solubility test was performed. The results are shown in Table 1.
Example 6
As shown in the following scheme 7, tris (4 ″ -hydroxymethylterphenylyl) amine (the compound of the above formula (32)) was obtained.

That is, 1.0 g of tris (4-iodophenyl) amine (a), 1.0 g of 4-bromophenylboronic acid (b3), 0.093 g of tetrakis (triphenylphosphine) palladium (0), 2N aqueous potassium carbonate solution 18 .3 g and 11 mL of tetrahydrofuran were charged into a 100 mL three-necked flask, heated to 63 ° C. with stirring, and reacted at this temperature with stirring for 5 hours. After completion of the reaction, the resulting reaction mixture was washed with water and purified by silica gel chromatography. The obtained purified product was recrystallized from a toluene / hexane mixed solvent to obtain 0.33 g of tris (4′-bromobiphenylyl) amine (c).
Next, 0.33 g of the above tris (4′-bromobiphenylyl) amine (c), 0.23 g of 4- (hydroxymethyl) phenylboronic acid (b2), 0.027 g of tetrakis (triphenylphosphine) palladium (0), A 2N aqueous potassium carbonate solution (5.2 g) and tetrahydrofuran (4 mL) were charged into a 100 mL three-necked flask, heated to 63 ° C. with stirring, and reacted at this temperature with stirring for 22 hours. After completion of the reaction, the resulting reaction mixture was washed with water and purified by silica gel chromatography. The obtained purified product was recrystallized from a tetrahydrofuran / hexane mixed solvent to obtain 0.1 g of the target tris (4 ″ -hydroxymethylterphenylyl) amine (the compound of the above formula (32)).
Elemental analysis value (% by weight):
C H N O
Calculated value 86.44 5.73 1.77 6.06
Measurement 86.20 5.78 1.56 6.46
Infrared absorption spectrum (KBr method):
FIG. 13 shows the FT-IR spectrum of tris (4 ″ -hydroxymethylterphenylyl) amine.
Molecular weight by mass spectrometry ((M + 1) / Z): 793
Differential scanning calorimetry (DSC):
As shown in FIG. 14, a DSC chart of tris (4 ″ -hydroxymethylterphenylyl) amine has melting points of 245.3 ° C., 251.2 ° C. and 255.9 ° C., and a glass transition point of 168.7. ° C.
Thermogravimetry / Differential calorimetry (TG / DTA):
As shown in FIG. 15 of the TG / DTA chart of tris (4 ″ -hydroxymethylterphenylyl) amine, the decomposition temperature was 478.7 ° C.
Ionization potential:
The ionization potential of the tris (4 ″ -hydroxymethylterphenylyl) amine thin film measured in the same manner as in Example 4 was 5.60 eV. Therefore, tris (4 ″ -hydroxymethylterphenylyl) amine The compound (32) can be suitably used as a hole injection and / or transport agent in an organic electroluminescence device.
Example 7
As shown in the following scheme 8, bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine (the compound of the formula (8)) was obtained. In Scheme 8, tbdms represents a t-butyldimethylsilyl group as in Scheme 8.

That is, 2.7 g of bis (4′-hydroxymethylbiphenylyl) amine (d) in which two hydroxyl groups were protected with a t-butyldimethylsilyl group and the hydroxyl group was protected with a t-butyldimethylsilyl group 4 -2.0 g of bromohydroxymethylbenzene (e) and 1.3 g of sodium t-butoxide were charged into a 200 mL three-necked flask together with 44 mL of xylene, and the temperature was raised to 120 ° C while stirring. Next, 0.01 g of palladium acetate and 0.02 g of t-butylphosphine were added and reacted at 120 ° C. with stirring for 5 hours. After completion of the reaction, the reaction product was extracted with toluene, the extract was purified by silica gel chromatography, and bis (4′-hydroxymethylbiphenylyl) in which three hydroxyl groups were protected with t-butyldimethylsilyl group. ) -4-hydroxyphenylamine (f) (2.0 g) was obtained as a colorless liquid. This was reacted with tetra-n-butylammonium fluoride in tetrahydrofuran to give 1.0 g of the desired bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine (compound of formula (8)). Obtained.
Elemental analysis value (% by weight):
C H N O
Calculated value 81.29 5.99 2.87 9.84
Measured value 81.05 6.02 2.70 10.23
Infrared absorption spectrum (KBr method):
FIG. 16 shows an FT-IR spectrum of bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine.
Molecular weight by mass spectrometry ((M + 1) / Z): 489
Differential scanning calorimetry (DSC):
As shown in FIG. 17 of the DSC chart of bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine, the melting point was not observed and the glass transition point was 79.9 ° C.
Thermogravimetry / Differential calorimetry (TG / DTA):
As shown in the TG / DTA chart of bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine in FIG. 18, the decomposition temperature was 418.0 ° C.
Ionization potential:
The ionization potential of the thin film of bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine measured in the same manner as in Example 4 was 5.64 eV. Accordingly, bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine can be suitably used as a hole injection and / or transport agent in an organic electroluminescence device.
Solubility measurement in organic solvents:
As described above, in the same manner as tris (4′-hydroxymethylbiphenylyl) amine (the compound of the formula (18)), bis (4′-hydroxymethylbiphenylyl) -4-hydroxyphenylamine is A solubility test in an organic solvent was conducted. The results are shown in Table 1.
Example 8
As shown in the following scheme 9, tris (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine (the compound of the formula (50)) was obtained. In Scheme 9, tbdms represents a t-butyldimethylsilyl group as in Scheme 8.

That is, 0.3 g of tris (4-iodophenyl) amine (a), 0.65 g of phenylethylene glycol 4-boronate (t) protected with two hydroxyl groups with a t-butyldimethylsilyl group, tetrakis (triphenyl) Phosphine) Palladium (0) 0.028 g, 2 N aqueous potassium carbonate solution 5.7 g and tetrahydrofuran 3 mL were charged into a 100 mL three-necked flask, heated to 63 ° C. with stirring, and allowed to react at this temperature with stirring for 15 hours. It was. After completion of the reaction, the resulting reaction mixture was washed with water and then purified by silica gel chromatography, and tris (4 ′-(1,2-) in which six hydroxyl groups were protected with t-butyldimethylsilyl group. 0.39 g of dihydroxyethyl) biphenylyl) amine (h) was obtained as a colorless liquid. Tris (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine (compound of formula (50)) 0 is prepared by allowing tetra-n-butylammonium fluoride to act on the compound (h) in tetrahydrofuran. 0.07 g was obtained.
Elemental analysis value (% by weight):
C H N O
Calculated 77.16 6.01 2.14 14.68
Measurement 76.98 6.20 2.06 14.76
Infrared absorption spectrum (KBr method):
The FT-IR spectrum of tris (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine is shown in FIG.
Molecular weight by mass spectrometry ((M + 1) / Z): 654
Differential scanning calorimetry (DSC):
As shown in the DSC chart of tris (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine in FIG. 20, neither melting point nor glass transition point was observed.
Ionization potential:
The ionization potential of the tris (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine thin film measured in the same manner as in Example 4 was 5.76 eV. Accordingly, tris (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine can be suitably used as a hole injection and / or transport agent in an organic electroluminescence device.
Solubility measurement in organic solvents:
As described above, in the same manner as the tris (4′-hydroxymethylbiphenylyl) amine (the compound of the formula (18)), the tris (4 ′-(1,2-dihydroxyethyl) biphenylyl) amine is A solubility test in an organic solvent was conducted. The results are shown in Table 1.

Example 9
Tris (4′-hydroxymethylbiphenylyl) amine (the compound of the above formula (18)) was dissolved in tetrahydrofuran at a concentration of 1.5% by weight. A solution of tris (4′-hydroxymethylbiphenylyl) amine (compound of formula (18)) in tetrahydrofuran was applied onto the ITO transparent electrode (anode) by spin coating, heated to 120 ° C., dried, A hole injection layer having a thickness of 40 nm was formed. Next, tris (p-terphenyl-4-yl) amine was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 60 nm. Further, a 75 nm thick light emitting layer made of tris (8-quinolinol) aluminum (Alq ₃ ) is formed on this hole transport layer, and a 0.75 nm thick lithium fluoride layer and a 100 nm thick light emitting layer are further formed thereon. Al layers were sequentially deposited and laminated to form a cathode, thus obtaining an organic electroluminescence device.
The organic electroluminescence device thus obtained was examined for luminance current efficiency (cd / A), luminous power efficiency (lm / W), and maximum luminance (cd / m ² ) at a current density of 25 mA / cm ^2. It was. The results are shown in Table 2.
Comparative Example 1
Instead of the tris (4′-hydroxymethylbiphenylyl) amine (compound of formula (18)), 4,4 ′, 4 ″ -tris (N- (2-naphthyl) -N-phenylamino) triphenylamine (2-TNANA) was vacuum-deposited on the ITO transparent electrode (anode) to form a 60 nm thick hole injection layer, which was measured in the same manner as in the compound (4). The ionization potential of the thin film was 5.14 eV Next, tris (p-terphenyl-4-yl) amine was vacuum deposited on the hole injection layer to form a hole transport layer having a thickness of 40 nm. Thereafter, an organic electroluminescence device was obtained in the same manner as in Example 8.
The organic electroluminescence device thus obtained was examined for luminance current efficiency (cd / A), luminous power efficiency (lm / W), and maximum luminance (cd / m ² ) at a current density of 25 mA / cm ^2. It was. The results are shown in Table 2.

The organic electroluminescence device according to the present invention is superior to the organic electroluminescence device according to the comparative example in all of luminance current efficiency, light emission power efficiency, luminance half life and maximum luminance.

The triarylamines according to the present invention have at least one hydroxyl group or hydroxyhydrocarbon group in the molecule and, according to a preferred embodiment, have a plurality of hydroxyl groups and / or hydroxyhydrocarbons in the molecule. Easily dissolved in polar solvents such as alcohols, preferably 1-butanol and benzyl alcohol, but not in nonpolar solvents such as toluene, while triarylamines according to the present invention are organic As an electronic material, for example, since it has excellent hole injecting property and / or transporting property, it can be suitably used as a hole injecting agent and / or a transporting agent, for example, in the production of an organic electroluminescence device.
In particular, in the production of an organic electroluminescence device, a hole injection is performed by applying a solution obtained by dissolving the triarylamine according to the present invention in a polar solvent on an appropriate substrate and drying it, that is, by a coating method. Layer and / or transport layer, and in such a case, even if the substrate contains an organic compound that dissolves in the nonpolar solvent but does not dissolve in the polar solvent, such a group can be formed. By forming a functional layer containing the triarylamines according to the present invention on the material by a coating method, an organic electroluminescence device having excellent performance can be obtained.
Further, for example, as described above, in the production of the organic electroluminescence device, after forming the hole transport layer containing the triarylamines according to the present invention, the hole transport layer is dissolved in a nonpolar organic solvent. Even when the solution of the light emitting material is applied, the hole transport layer is not dissolved in the nonpolar organic solvent, and thus does not hinder the formation of the light emitting layer by the application method.

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2 ... Anode 3a ... Hole injection layer 3b ... Hole transport layer 4 ... Light emitting layer 5 ... Cathode 6 ... Power supply

Claims

Formula (I)

(In the formula, A 1 to A 3 are each independently a phenylene group which may have a substituent, and X 1 to X 3 are each independently a formula (II)

Wherein R 1 to R 5 are each independently an aliphatic carbon having a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, a hydroxyl group, or at least one hydroxyl group. A hydrogen group, and m, n and p are each independently 0, 1 or 2.)
In at least one of X 1 to X 3 , at least one of R 1 to R 5 is a hydroxyl group or an aliphatic hydrocarbon group having at least one hydroxyl group. )
Triarylamines represented by
Formula (I)

(In the formula, A 1 to A 3 are each independently a phenylene group which may have a substituent, and X 1 to X 3 are each independently a formula (II)

Wherein R 1 to R 5 are each independently an aliphatic carbon having a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, a hydroxyl group, or at least one hydroxyl group. A hydrogen group, and m, n and p are each independently 0, 1 or 2.)
In any of X 1 to X 3 , at least one of R 1 to R 5 is a hydroxyl group or an aliphatic hydrocarbon group having at least one hydroxyl group. )
Triarylamines represented by
The triarylamines according to claim 1 or 2, wherein A 1 to A 3 are each independently a p-phenylene group which may have a substituent.
The triarylamine according to claim 1, which is bis (4'-hydroxymethylbiphenylyl) -4-hydroxymethylphenylamine.
The triarylamine according to claim 1, which is tris (4'-hydroxybiphenylyl) amine.
The triarylamine according to claim 1, which is tris (3'-hydroxybiphenylyl) amine.
The triarylamine according to claim 1, which is tris (4'-hydroxy-3 ', 5'-dimethylbiphenylyl) amine.
The triarylamine according to claim 1, which is tris (4'-hydroxymethylbiphenylyl) amine.
The triarylamine according to claim 1, which is tris (3'-hydroxymethylbiphenylyl) amine.
The triarylamine of claim 1, which is tris (4 "-hydroxymethylterphenylyl) amine.
The triarylamine of claim 1, which is tris (4 '-(1,2-dihydroxyethyl) biphenylyl) amine.
The organic electronic material containing the triarylamines in any one of Claim 1 to 11.
The organic electroluminescent element which has at least 1 functional layer containing the organic electronic material of Claim 12.
The organic electroluminescent element which uses the organic electronic material of Claim 12 as a hole transport and / or injection agent.