TW201512373A - Compound and organic electroluminescence element - Google Patents

Abstract

A compound of the present invention includes a diaminobiphenyl group which is disposed between two dibenzothiophene groups or between two dibenzofuran groups which is represented by the following general formula (1-1). In the general formula (1-1), two of the A are identical and either oxygen or sulfur. Xa and Xb independently represent hydrogen or any one of the following (a) to (c). If any one of Xa or Xb is hydrogen, the other is not hydrogen. Ya and Yb independently represent the following (d). (a) represents a straight-chain or cyclic alkyl or alkoxy group which may have a substituent. The substituent of the straight-chain or cyclic alkyl or alkoxy group (a) is any one of an alkyl group, a halogen group, an amino group, a nitro group, or a cyano group. (b) and (d) are aroma cyclic groups which may have substituents. The substituent of the aroma cyclic group which may have the substituent is any one of a straight-chain or cyclic alkyl group, a halogen group, an amino group, a nitro group, or a cyano group. The aromatic cyclic groups (b) and (d) are an aromatic hydrocarbon group or an aromatic heterocyclic group. (c) is a halogen group, an amino group, a nitro group, or a cyano group.

Description

Compounds and organic electroluminescent elements

The present invention relates to a compound and an organic electroluminescence (hereinafter abbreviated as organic EL) element having a hole transporting layer containing the compound.

Background technique

The organic EL element has a structure in which a luminescent material is sandwiched between a cathode and an anode, and the luminescent material emits light by an electric field. The organic EL element is an element that recombines a hole injected from an electrode and electrons in the light-emitting layer to cause the light-emitting material to emit light.

The organic EL element is self-luminous, and has a wide viewing angle and excellent visibility. Therefore, the organic EL element is used as a display element of a display or the like. Further, the organic EL element is a thin solid element, which is lightweight and excellent in strength. Therefore, the display using the organic EL element is not limited to a stationary type such as a television, and is also useful for mobile use. Further, since the display element using the organic EL element can be easily changed in size and emitted on the entire surface, it is also useful for illumination applications.

The subject of the organic EL element is, for example, an improvement in luminous efficiency (external quantum efficiency) and a long life. In order to solve the above problems, various efforts have been made so far.

For example, the organic EL element is provided with a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer in addition to the electrode and the light-emitting layer. Usually, these layers are laminated in the order of an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode. In addition to the electrodes and the light-emitting layer, by providing such layers, the probability of recombination of the holes and electrons in the light-emitting layer can be improved, and the luminous efficiency of the organic EL element can be improved.

Further, in order to increase the efficiency of the organic EL element, a phosphorescent material has been proposed as a light-emitting material of the light-emitting layer. When the luminescent material exhibits an excited state, the excited singlet state (S ₁ ) and the excited triplet state (T ₁ ) are generated at a probability of 1:3. Then, when the luminescent material returns from the excited state to the ground state, the energy is released in the form of light.

When a luminescent material is used as a fluorescent material, only the energy derived from S ₁ is converted into light. In contrast, when a phosphorescent material is used, the energy derived from T ₁ is also converted into light. Therefore, an organic EL device using a phosphor material is more efficient than an organic EL device using a fluorescent material as a light-emitting material (see, for example, Non-Patent Document 1 and Non-Patent Document 2).

Phosphorescent materials are typically used with host materials. In an organic EL device having a light-emitting layer containing a host material and a phosphorescent material, energy of a host material excited by recombination of a hole and electrons moves to a phosphorescent material. The phosphorescent material releases light energy as the energy is excited. In order to make efficient energy transfer of the host material to the phosphor material, it is necessary to make the energy of the excited triplet state (T ₁ ) of the host material larger than that of the phosphor material of the guest material (for example, refer to Non-Patent Document 3).

To date, most of the host materials available for the luminescent layer have been reported. For example, the host material may be an oxazole compound or the like (for example, refer to Non-Patent Document 4). For the carbazole-based compound, CBP or the like represented by the following formula (3) can be suitably used as a host material (for example, refer to Non-Patent Document 5).

The host material composed of the carbazole compound has a relatively large T ₁ energy. However, when the T ₁ energy of the guest material is too large, the host material may not sufficiently improve the luminous efficiency even when CBP is used. Therefore, a CDBP represented by the following general formula (4) in which the energy of T _{1 is} further increased may be used as a host material composed of an oxazole compound (see, for example, Non-Patent Document 3).

In general, a carbazole-based compound used as a host material exhibits hole transportability.

A large number of electron transporting materials or two-charge transporting materials used as host materials have also been reported (for example, refer to Non-Patent Document 6). Even if the luminescent layer contains the host material and the guest material composed of the luminescent material and the host material uses an organic EL element of an electron transporting material or a second charge transporting material, it is necessary to make the T ₁ energy of the host material itself larger than the guest material.

Further, in order to increase the efficiency of the organic EL element, there is a demand for a hole transport layer which can obtain high hole transportability, high electron blocking property, and high T ₁ energy. In addition, in order to extend the life of the organic EL device, a high electrical/thermal stability is required for the material of the hole transport layer used in the hole transport layer (see, for example, Non-Patent Document 7 and Non-Patent Document 8).

The hole transport layer material used for the hole transport layer must be HOMO level, LUMO level, band gap energy, etc. from the viewpoint of hole transportability and electron blockage of the hole transport layer using the hole transport layer. The characteristics will be of a suitable value. The appropriate value of the electrical characteristics of the hole transport layer varies depending on the material disposed on both sides of the hole transport layer. In particular, the electrical characteristics of the hole transport layer are preferably adapted to the material of the luminescent layer, and the luminescent layer is disposed on one side of the hole transport layer.

For example, on the side of one side of the hole transport layer, the luminescent material is provided with a luminescent layer of a general green luminescent material or a blue luminescent material, and the other side is provided with a hole injection layer composed of PEDOT:PSS. The material of the hole transport layer should be used in the vicinity of -5.0~-6.0eV. By using such a hole transport layer material to make the HOMO level suitable, a hole transport layer capable of obtaining excellent hole transportability can be formed.

In addition, the LUMO level of the hole transport layer should be higher than the LUMO level of the light-emitting layer. For example, when the LUMO level of the luminescent material is -2.8 eV, the LUMO level of the hole transport layer should be above -2.8 eV, and It should be -2.6eV or more. By using a hole transport layer material that exhibits such a LUMO level, a hole transport layer having an electron blocking effect of encapsulating electrons injected into the light-emitting layer can be obtained.

In addition, the band gap energy of the hole transport layer necessarily depends on the HOMO level and the LUMO level. In order to increase the efficiency of the organic EL element, it is preferable to use a band gap energy of the hole transport layer to be a hole transport layer material of 3.0 eV or more.

Further, when the light-emitting layer is a phosphor material for the guest material and the electron transport material or the second charge transport material is used as the host material, in order to prevent the energy from being reversed and the organic EL element is made more efficient, not only the host material but also the hole transport layer. The T ₁ energy of the material is also important. Specifically, should the electrical hole transport layer material of the T ₁ energy greater than the energy of _a guest material of T. For example, when the guest material uses Ir(mppy) _{3 of a} green phosphorescent material, the T ₁ energy of the guest material becomes 2.35 eV. Therefore, the T ₁ energy of the host material and the hole transport layer material is preferably a value of 2.35 eV or more.

The material of the hole transport layer has been reported as a DBTPB represented by the following formula (5) (for example, refer to Patent Document 1). DBTPB has a T ₁ energy of 2.35 eV, which is equivalent to Ir(mppy) _{3 of a} general phosphorescent material. Therefore, when the guest material uses Ir(mppy) ₃ , the material of the hole transport layer should preferably use a material having a larger T ₁ energy than DBTPB.

[化3]

Advanced technical literature Patent literature

[Patent Document 1] Japanese Patent Publication No. 2011-527122

Non-patent literature

[Non-Patent Document 1] Nature, 395, 151 (1998)

[Non-Patent Document 2] Nature, 403, 750 (2000)

[Non-Patent Document 3] Appl. Phys. Lett., 83, 569 (2003)

[Non-Patent Document 4] Adv. Mater., 23, 926 (2011)

[Non-Patent Document 5] Appl. Phys. Lett., 82, 2422 (2003)

[Non-Patent Document 6] Adv. Mater., 22, 3311 (2010)

[Non-Patent Document 7] Adv. Mater., 24, 3212 (2012)

[Non-Patent Document 8] Adv. Mater., 22, 2468 (2010)

Summary of invention

An object of the present invention is to provide a compound which can be used as a hole transporting material, which can obtain a band gap energy, an electric property and a thermal stability. Different hole transport layer.

Further, an object of the invention is to provide an organic EL device having a long life and high luminous efficiency, and the organic EL device has a hole transport layer containing the above compound.

The inventor of the present invention has carefully studied in view of the above problems. As a result, a novel compound represented by the following formula (1-1) which is suitable as a hole transporting material for an organic EL device has been found. In addition, it has been confirmed that an organic EL device using a compound represented by the following formula (1-1) as a material for a hole transport layer can have a long life and high efficiency.

The reason why the compound represented by the following formula (1-1) is used as a material of the hole transport layer to increase the efficiency of the organic EL device is as follows.

That is, the compound represented by the following formula (1-1) is a substance comprising a diaminobiphenyl group having a central structure of a molecular structure and two dibenzothiophenes or two dibenzofurans. On the other hand, the diaminobiphenyl genes Xa and Xb disposed between two dibenzothiophenes or two dibenzofurans disintegrate planarity. Therefore, it is estimated that the band gap energy of the hole transport layer using the compound represented by the following formula (1-1) becomes wider. Furthermore, in the general formula (1-1), Ya and Yb are specific substituents shown below. Therefore, it is estimated that the electrical characteristics of the organic EL element having the hole transport layer using the compound represented by the general formula (1-1) become an appropriate value.

The gist of the present invention is as follows.

(1) A compound represented by the following formula (1-1), which comprises a diaminobiphenyl group disposed between two dibenzothiophenes or between two dibenzofurans.

【化4】

In the general formula (1-1), two A are the same as oxygen or sulfur; Xa and Xb each independently represent hydrogen or any one of the following (a) to (c), and either of Xa and Xb When it is hydrogen, the other is hydrogen; Ya and Yb each independently represent (d); (a) is a linear or cyclic alkyl or alkoxy group which may have a substituent, and a) the substituent of the linear or cyclic alkyl or alkoxy group which may have a substituent is any one of an alkyl group, a halogen group, an amine group, a nitro group and a cyano group; (b), (d) The aromatic cyclic group which may have a substituent, and the substituent of the aromatic ring group which may have a substituent of (b), (d) is a chain or a cyclic alkyl group, a halogen group, an amine group, and a nitrate Any one of a group and a cyano group, the aromatic ring group of (b) and (d) is an aromatic hydrocarbon group or an aromatic heterocyclic group; (c) is a halogen group, an amine group, a nitro group and a cyano group. Either.

A compound of the following formula (1-2), characterized in that it contains a diaminobiphenyl group disposed between two dibenzothiophenes or between two dibenzofurans, and is bonded to The bonding position of the amino group of the aforementioned diaminobiphenyl group is 4, 4'position;

In the general formula (1-2), two A are the same as oxygen or sulfur; Xa and Xb each independently represent hydrogen or any one of the following (a) to (c), and any of Xa and Xb When it is hydrogen, the other is hydrogen; Ya and Yb each independently represent (d); (a) is a linear or cyclic alkyl or alkoxy group which may have a substituent, and The substituent of (a) a linear or cyclic alkyl group or alkoxy group which may have a substituent is any one of an alkyl group, a halogen group, an amine group, a nitro group and a cyano group; (b), (d) Is an aromatic cyclic group which may have a substituent, and the substituent of the aromatic ring group which may have a substituent of (b) and (d) is a chain or a cyclic alkyl group, a halogen group, an amine group, Any one of a nitro group and a cyano group, the aromatic ring group of (b) and (d) is an aromatic hydrocarbon group or an aromatic heterocyclic group; (c) is a halogen group, an amine group, a nitro group and a cyano group. Any of them.

(3) A compound according to (1) or (2), wherein either or both of Xa and Xb are a methyl group.

(4) A compound according to any one of (1) to (3), wherein any of Ya and Yb One or both are phenyl groups.

(5) A compound according to any one of (1) to (3), wherein either or both of Ya and Yb are 2,2'-dimethyl-1,1'-biphenyl.

(6) The compound according to any one of (1) to (5), wherein the substitution position of the two dibenzothiophenes or the substitution position of the two dibenzofurans is 4 positions.

(7) The compound according to any one of (1) to (5), wherein the substitution position of the two dibenzothiophenes or the substitution position of the two dibenzofurans is two.

(8) An organic electroluminescence device comprising a light-emitting layer between a cathode and an anode and a hole transport layer disposed on the anode side of the light-emitting layer, wherein the hole transport layer contains (1) The compound of any one of (7).

(9) The organic electroluminescence device according to (8), wherein the light-emitting layer contains a host material and a guest material composed of the light-emitting material, and the guest material is an electron transporting material or a second charge transporting property of a hole and an electron. material.

(10) The organic electroluminescence device according to (9), wherein the guest material is a phosphorescent material.

The compound of the present invention can be used as a hole transporting material, and it can obtain a hole transporting layer having a large band gap energy and excellent electrical and thermal stability.

Further, since the organic EL device of the present invention has a hole transport layer containing the compound of the present invention, it has a long life and high luminous efficiency. In particular, when the light-emitting layer contains a host material composed of an electron transporting material or a two-charge transporting material and a guest material composed of a phosphorescent material, it can be an organic EL device having high luminous efficiency.

1, 1A‧‧‧Organic EL elements (organic electroluminescent elements)

2‧‧‧Substrate

3‧‧‧2nd electrode

4‧‧‧Electronic injection layer

5‧‧‧Electronic transport layer

6‧‧‧Lighting layer

7‧‧‧ hole transport layer

8‧‧‧ hole injection layer

9‧‧‧1st electrode

Fig. 1 is a schematic cross-sectional view for explaining an example of an organic EL device of the present invention.

Fig. 2 is a schematic cross-sectional view for explaining another example of the organic EL device of the present invention.

Fig. 3 is a graph showing the results of luminescence spectrometry of the film of Experimental Example 1, the film of Experimental Example 6, and the DBTPB film at room temperature.

Fig. 4 is a graph showing the results of luminescence spectrum measurement of the film of Experimental Example 1, the film of Experimental Example 6 and the DBTPB film at a low temperature, and the luminescence spectrum measurement results of a film composed of Ir(mppy) ₃ at room temperature.

Fig. 5 is a graph showing the relationship between the current density and the external quantum efficiency of the organic EL elements of Experimental Example 2 and Experimental Example 3.

Fig. 6 is a graph showing the relationship between the driving time and the luminance of the organic EL elements of Experimental Example 2 and Experimental Example 3.

Fig. 7 is a graph showing the relationship between the current density and the external quantum efficiency of the organic EL elements of Experimental Example 4 and Experimental Example 5.

Fig. 8 is a graph showing the relationship between the driving time and the luminance of the organic EL elements of Experimental Example 4 and Experimental Example 5.

Fig. 9 is a graph showing the relationship between the current density and the external quantum efficiency of the organic EL devices of Experimental Example 7 and Experimental Example 8.

Form for implementing the invention

The invention is further described in detail below.

The compound of the present invention is represented by the above formula (1-1).

Since the compound represented by the formula (1-1) contains a diaminobiphenyl group having a central structure of a molecular structure and two dibenzothiophenes or two dibenzofurans, and Xa, Xb, Ya, and Yb are as follows It has specific properties and excellent electrical and thermal stability.

In the general formula (1-1), two A's are the same as oxygen or sulfur.

Xa and Xb are introduced for the purpose of disintegrating the planarity of the diaminobiphenyl group of the central skeleton of the molecular structure, and augmenting it as the band gap energy of the hole transport layer of the material of the hole transport layer.

Xa and Xb each independently represent hydrogen or any one of the following (a) to (c). When either of Xa and Xb is hydrogen, the other is hydrogen.

(a) is a linear or cyclic alkyl group or alkoxy group which may have a substituent, and (a) a linear or cyclic alkyl group or alkoxy group which may have a substituent is an alkyl group, Any of a halogen group, an amine group, a nitro group, and a cyano group; (b) is an aromatic cyclic group which may have a substituent, and (b) the substituent of the aromatic cyclic group which may have a substituent is a chain or a cyclic alkyl group, a halogen group, an amine group, a nitro group And the cyano group, the aromatic ring group of (b) is an aromatic hydrocarbon group or an aromatic heterocyclic group; (c) is any of a halogen group, an amine group, a nitro group, and a cyano group. (a) In the linear or cyclic alkyl group or alkoxy group which may have a substituent, the alkyl group is preferably an alkyl group having 1 to 25 carbon atoms, and is linear, branched or cyclic. Anyone can do it.

From the viewpoint of thermal stability and glass transition temperature, a linear or branched alkyl group is preferably a carbon number of 1 to 15, and from the viewpoint of avoiding steric hindrance caused by excessive Xa and/or Xb. It is more suitable for carbon number 1~8.

From the viewpoint of dispersing the planarity of the diaminobiphenyl group of the central skeleton by Xa and Xb, the cyclic alkyl group is preferably a carbon number of 3 or more. Further, from the viewpoint of avoiding steric hindrance caused by excessive Xa and/or Xb, the cyclic alkyl group is preferably a carbon number of 8 or less.

Specific examples of the linear alkyl group having 1 to 25 carbon atoms of the above (a) include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group and n-octyl group. Base, n-decyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecane , n-octadecyl, n-nonadecyl, n-icosyl, n-docosyl, n-docosyl, n-tricosyl, n-tetracosyl, branched The alkyl group may, for example, be 1-methylethyl, 1-methylpropyl, 1-ethylpropyl, 1-n-propylpropyl, 1-methylbutyl, 1-ethylbutyl, 1 -propylbutyl, 1-n-butylbutyl, 1-methylpentyl, 1-ethylpentyl, 1-n-propylpentyl, 1-n-pentylpentyl, 1-methylhexyl, 1 -ethylhexyl, 1-n-propylhexyl, 1-n-butylhexyl, 1-n-pentylhexyl, 1-n-hexylhexyl, 1-methylheptyl, 1-ethylheptyl, 1-n-propyl Heptyl, 1-n-butylheptyl, 1-n-pentylheptyl, 1-n-heptylheptyl, 1-methyloctyl, 1-ethyloctyl, 1-n-propyloctyl, 1- n-Butyloctyl, 1-正Kesinyl, 1-n-hexyloctyl, 1-n-heptyloctyl, 1-n-octyloctyl, 1-methylindenyl, 1-ethylindenyl, 1-n-propyldecyl, 1 - n-butyl fluorenyl, 1-n-pentyl fluorenyl, 1-n-hexyl fluorenyl, 1-n-heptyl fluorenyl, 1-n-octyl fluorenyl, 1-n-decyl fluorenyl, 1-methyl fluorenyl, iso- Propyl, tert-butyl, 2-methylbutyl, 2-ethylbutyl, 2-n-propylpentyl, 2-methylhexyl, 2-ethylhexyl, 2-n-propylhexyl, 2 - n-butylhexyl, 2-methylheptyl, 2-ethylheptyl, 2-n-propylheptyl, 2- n-Butylheptyl, 2-n-pentylheptyl, 2-methyloctyl, 2-ethyloctyl, 2-n-propyloctyl, 2-n-butyloctyl, 2-n-pentyloctyl, 2-n-hexyloctyl, 2-methylindenyl, 2-ethylindenyl, 2-n-propyldecyl, 2-n-butylindenyl, 2-n-pentyldecyl, 2-n-hexyldecyl, 2-n-heptyldecyl, 2-methylindenyl, 2,3-dimethylbutyl, 2,3,3-trimethylbutyl, 3-methylbutyl, 3-methylpentyl , 3-ethylpentyl, 4-methylpentyl, 4-ethylhexyl, 2,3-dimethylpentyl, 2,4-dimethylpentyl, 2,4,4-trimethyl Pentyl, 2,3,3,4-tetramethylpentyl, 3-methylhexyl, 2,5-dimethylhexyl, 3-ethylhexyl, 3,5,5-trimethylhexyl, 4 -Methylhexyl, 6-methylheptyl, 3,7-dimethyloctyl, 6-methyloctyl, and the cyclic alkyl group may, for example, be a cyclopropyl group, a cyclobutyl group, a cyclopentyl group or a ring. Hexyl, cycloheptyl, cyclooctyl and the like.

With respect to the alkyl group of the above (a), methyl, ethyl, n-propyl and isopropyl groups are used from the viewpoint of the planarity of the diaminobiphenyl group of the disintegration center skeleton and avoiding excessive steric hindrance. , n-butyl, tert-butyl, n-pentyl and n-hexyl are preferred. The alkyl group of the above (a) is more preferably a methyl group from the viewpoint of easiness of synthesis. When the alkyl group of the above (a) is a methyl group, only one of Xa and Xb may be a methyl group, or both of them may be a methyl group. From the standpoint of ease of synthesis, it is more preferable that both are methyl groups.

(a) Among the linear or cyclic alkyl groups or alkoxy groups which may have a substituent, the alkoxy group may be either linear or branched.

The linear or branched alkoxy group preferably has a carbon number of 1 to 15 from the viewpoint of thermal stability and glass transition temperature, and has a carbon number of 1 to 8 from the viewpoint of avoiding excessive steric hindrance. Especially good.

The alkoxy group of the above (a) may specifically be exemplified by a methoxy group, an ethoxy group, N-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-decyloxy, n-decyloxy, n-dodecyloxy, isopropoxy , 2-ethylpentyloxy, 2-ethylhexyloxy, 2-ethylheptyloxy, 2-ethyloctyloxy, 2-ethylindenyloxy, 2-ethylindole Baseoxy and the like.

The substituent of the alkyl group or alkoxy group of the above (a) may be any of an alkyl group, a halogen group, an amine group, a nitro group and a cyano group. When the alkyl group or alkoxy group of the above (a) has a substituent, the number of substituents which the alkyl group or the alkoxy group has is not particularly limited. When the number of substituents of the alkyl group or alkoxy group of the above (a) is 2 or more, the substituents may be all the same or different from each other.

The alkyl group or alkoxy group of the above (a) having such a substituent can cause planar disintegration of the diaminobiphenyl group of the central skeleton of the molecular structure. The alkyl group as the substituent of the above (a) is preferably an alkyl group having 1 to 8 carbon atoms from the viewpoint of avoiding excessive steric hindrance. Further, the halogen group as the substituent of the above (a) is preferably a fluorine group.

(b) The aromatic cyclic group which may have a substituent is an aromatic hydrocarbon group or an aromatic heterocyclic group.

The aromatic hydrocarbon group of the above (b) may be, for example, a carbon number of 6 to 30. Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include a 6π electron system, a 10π electron system, a 12π electron system, and a 14π electron system. Specific examples of the aromatic hydrocarbon group include a phenyl group, a biphenyl group, a naphthyl group, a terphenyl group, a fluorenyl group, a fluorenyl group, a fluorenyl group, an anthracenyl group, a phenanthryl group, a naphthryl group, and the like. Among these aromatic hydrocarbon groups, a phenyl group and a naphthyl group are preferable, and a phenyl group is particularly preferable from the viewpoints of easiness of synthesis and planar disintegration of a diaminobiphenyl group of a central skeleton.

The aromatic heterocyclic group of the above (b) may, for example, be a carbon number of 1 to 30. Examples of the aromatic heterocyclic group having 1 to 30 carbon atoms include a 6π electron system, a 10π electron system, a 12π electron system, and a 14π electron system. The aromatic heterocyclic group may specifically be exemplified by a thienyl group, a furyl group, a pyrrolyl group, a thiazolyl group, an isothiazolyl group, a pyrazolyl group, Azolyl, different Azolyl, pyridyl, anthracene base, Diazolyl, imidazolyl, tri Base, thiadiazolyl, benzothiazolyl, benzimidazolyl, benzo Azolyl, benzo Diazolyl, benzotriazolyl, benzothiadiazolyl, benzoselenadiazolyl, thieno[2,3-b]thienyl, thieno[3,2-b]thienyl, thieno [3,4-b]thienyl, 9-oxoindolyl, oxazolyl, dibenzophenylthio, silafluorenyl, selenofluorenyl, Xanthenyl, phenanthrolyl, pheno Phenazilyl base( ) base.

The substituent of the (b) aromatic cyclic group which may have a substituent is a chain or a cyclic alkyl group, a halogen group, an amine group, a nitro group, and a cyano group. When the aromatic cyclic group of the above (b) has a substituent, the number of substituents is not particularly limited. When the number of the substituents of the aromatic ring group in the above (b) is 2 or more, the substituents may be all the same or different from each other.

The aromatic cyclic group of the above (b) having such a substituent can cause planar disintegration of the diaminobiphenyl group of the central skeleton of the molecular structure. The chain or cyclic alkyl group as the substituent of the above (b) is preferably a carbon number of 1 to 25, and is preferably one having a carbon number of 1 to 8 from the viewpoint of avoiding excessive steric hindrance and lowering of glass transition temperature. .

The halogen group represented by Xa and Xb and which is any one of (c) a halogen group, an amine group, a nitro group and a cyano group may, for example, be an iodine group, a bromo group, a chloro group or a fluorine group. Among the above-mentioned (c) halogen groups, from the ease of synthesis, molecular stability and the center bone From the viewpoint of planar disintegration of the diaminobiphenyl group, it is particularly preferably a fluorine group. Xa and Xb may be the same or different.

When either of Xa and Xb is hydrogen, the other is hydrogen. At this time, the planarity of the diaminobiphenyl group of the central skeleton of the molecular structure can be disintegrated. When either of Xa and Xb is hydrogen, the other is (a) a linear or cyclic alkyl or alkoxy group which may have a substituent, and (b) an aromatic ring which may have a substituent And (c) any one of a halogen group, an amine group, a nitro group, and a cyano group.

In the general formula (1-1), Ya and Yb are used for the hole transport layer material, and the HOMO level, LUMO level, and band gap energy of the hole transport layer of the compound represented by the formula (1-1) are used. The characteristics are those with appropriate values.

Ya and Yb each independently represent (d) an aromatic cyclic group which may have a substituent. The substituent of the above (d) aromatic cyclic group which may have a substituent is a chain or a cyclic alkyl group, a halogen group, an amine group, a nitro group and a cyano group. The aromatic cyclic group of the above (d) is an aromatic hydrocarbon group or an aromatic heterocyclic group.

Ya and Yb can be the same or different.

The aromatic hydrocarbon group as the aromatic ring group of the above (d) has a carbon number of 6 from the viewpoints of physical properties such as electrical characteristics, thermal stability and glass transition temperature of the hole transport layer, and steric hindrance effects. 30 is better. Further, examples of the aromatic hydrocarbon group include a 6π electron system, a 10π electron system, a 12π electron system, and a 14π electron system. Specific examples of the aromatic hydrocarbon group include a phenyl group, a biphenyl group, a naphthyl group, a terphenyl group, a fluorenyl group, a fluorenyl group, a fluorenyl group, a fluorenyl group, a phenanthryl group, a naphthryl group and the like. In the case of the aromatic hydrocarbon group, in order to obtain a material for the hole transport layer which can form a hole transport layer having appropriate electrical properties, a phenyl group, a naphthyl group and a biphenyl group are preferable. When the aromatic ring group of the above (d) is a phenyl group, Ya and Yb Only one of them may be a phenyl group, or both of them may be a phenyl group. From the viewpoint of obtaining a hole transporting material which can form a hole transporting layer having more suitable electrical characteristics, it is more preferable that both are phenyl groups.

When the aromatic hydrocarbon group of the aromatic cyclic group (d) is a biphenyl group, an alkyl group such as a methyl group is introduced in an ortho position corresponding to a bonding position between the phenyl groups in the biphenyl group. It is better. This biphenyl gene has a steric hindrance and becomes a distortion of the biphenyl skeleton, and the expansion of the π-conjugated system is suppressed. Therefore, a hole transport layer material which can form a hole transport layer having more suitable electrical characteristics can be obtained. Preferably, the biphenyl group having an alkyl group such as a methyl group introduced into the ortho position of the bonding position of the phenyl groups is preferably a 2,2'-dimethyl-1,1'-biphenyl group. When the aromatic ring group of the above (d) is 2,2'-dimethyl-1,1'-biphenyl, only one of Ya and Yb may be 2,2'-dimethyl- 1,1'-biphenyl, or both, 2,2'-dimethyl-1,1'-biphenyl. From the viewpoint of suppressing the expansion of the π-conjugated system and obtaining the hole transporting material of the hole transporting layer having suitable electrical properties, it is more preferable that both are 2,2'-dimethyl-1,1' -biphenyl.

The aromatic heterocyclic group as the aromatic cyclic group of the above (d) is preferably carbon from the viewpoints of physical properties such as electrical properties, thermal stability, and glass transition temperature of the hole transport layer and steric hindrance effects. Number 1~30. Further, examples of the aromatic heterocyclic group include a 6π electron system, a 10π electron system, a 12π electron system, and a 14π electron system. The aromatic heterocyclic group may specifically be exemplified by a thienyl group, a furyl group, a pyrrolyl group, a thiazolyl group, an isothiazolyl group, a pyrazolyl group, Azolyl, different Azolyl, pyridyl, anthracene base, Diazolyl, imidazolyl, tri Base, thiadiazolyl, benzothiazolyl, benzimidazolyl, benzo Azolyl, benzo Diazolyl, benzotriazolyl, benzothiadiazolyl, benzoselenadiazolyl, thieno[2,3-b]thienyl, thieno[3,2-b]thienyl, thieno [3,4-b]thienyl, 9-side oxonyl, oxazolyl, dibenzophenylthio, anthracenyl, selenium fluorenyl, Base, phenanthrolyl, pheno Phenazilyl base( )Wait. In the case of an aromatic heterocyclic group, in order to obtain a material for a hole transport layer which can form a hole transport layer having suitable electrical properties, a dibenzophenylthio group is particularly preferred.

The substituent of the (d) aromatic cyclic group which may have a substituent is a chain or a cyclic alkyl group, a halogen group, an amine group, a nitro group, and a cyano group. When the aromatic cyclic group of the above (d) has a substituent, the number of substituents is not particularly limited. When the number of the substituents of the aromatic ring group in the above (d) is 2 or more, the substituents may be all the same or may be different from each other.

The chain or cyclic alkyl group as the substituent of the above (d) is preferably a methyl group, an ethyl group, a propyl group or an isopropyl group from the viewpoint of a suitable steric barrier effect.

The halogen group as the substituent of the above (d) is preferably a fluorine group from the viewpoint of easiness of synthesis.

In the general formula (1-1), when one or more substituents represented by Xa, Xb, Ya, and Yb have too many carbon atoms, the following problems may occur. In other words, steric hindrance due to excessive substitution of one or more of Xa, Xb, Ya, and Yb is likely to occur. Further, the glass transition temperature is lowered, and the heat stability is likely to become insufficient. Further, when the compound represented by the formula (1-1) is used as a material for a hole transport layer of an organic EL device, a charge transfer site which becomes a core portion is relatively reduced, and electrical characteristics are easily lowered. Therefore, the substituent represented by Xa, Xb, Ya, and Yb in the formula (1-1) is preferably a carbon number of 30 or less.

When the compound of the present invention contains a diaminobiphenyl group disposed between two dibenzothiophenes and two dibenzothiophenes, specific examples thereof include the following general formulae (1-6) to (1-10). The compound shown.

Further, in the following general formulae (1-6) to (1-10), Xa and Xb each independently represent: hydrogen, (a) a linear or cyclic alkyl group or alkoxy group which may have a substituent, (b) Any of an aromatic cyclic group which may have a substituent, (c) a halogen group, an amine group, a nitro group, and a cyano group. When either of Xa and Xb is hydrogen, the other is hydrogen. The substituent of (a) a linear or cyclic alkyl group or alkoxy group which may have a substituent is any of an alkyl group, a halogen group, an amine group, a nitro group and a cyano group. The substituent of the (b) aromatic cyclic group which may have a substituent is a chain or a cyclic alkyl group, a halogen group, an amine group, a nitro group, and a cyano group. The aromatic ring group of (b) is an aromatic hydrocarbon group or an aromatic heterocyclic group.

In the following general formulae (1-6) to (1-10), each of Ya and Yb independently represents (d) an aromatic cyclic group which may have a substituent. The substituent of the above (d) aromatic cyclic group which may have a substituent is a chain or a cyclic alkyl group, a halogen group, an amine group, a nitro group and a cyano group. The aromatic cyclic group of the above (d) is an aromatic hydrocarbon group or an aromatic heterocyclic group.

【化6】

Further, the compound represented by the above formula (1-6) to (1-10) is an example of the compound of the present invention, and the technical scope of the present invention is not limited by these compounds.

The compound represented by the formula (1-1) contains a bond of an amine group bonded to a diaminobiphenyl group when a diaminobiphenyl group is disposed between two dibenzothiophenes and two dibenzothiophenes. The knot is not particularly limited. For example, it may be in the 5,5' position, as shown in the formula (1-6); it may be in the 4, 5' position, as in the compound of the formula (1-7); it may be 3 , 3' position, like the compound of the formula (1-8); can be 4, 3' position, such as the compound of the formula (1-9); can be 5, 3' position, such as It is the same as the compound represented by the formula (1-10); it may be in the 4,4' position, and the compound represented by the formula (1-2).

From the standpoint of ease of synthesis, the bonding position of the amine group bonded to the diaminobiphenyl group is preferably 5, 5' or 4, 4'.

When the compound of the formula (1-1) contains a diaminobiphenyl group disposed between two dibenzothiophenes and two dibenzothiophenes, two dibenzothiophenes The substitution position may be any one of 1 to 4 positions, and may be different from each other. The substitution position of the two dibenzothiophenes is preferably 2 or 4 from the viewpoint of the ease of synthesis of the compound.

When the compound of the present invention contains a diaminobiphenyl group disposed between two dibenzofurans and two dibenzofurans, specific examples thereof include the following formulas (2-6) to (2-10). The compound shown.

Further, in the following general formulae (2-6) to (2-10), Xa and Xb each independently represent hydrogen, (a) a linear or cyclic alkyl group or alkoxy group which may have a substituent, and (b) Any of an aromatic cyclic group having a substituent, (c) a halogen group, an amine group, a nitro group, and a cyano group. When either of Xa and Xb is hydrogen, the other is hydrogen. The substituent of (a) a linear or cyclic alkyl group or alkoxy group which may have a substituent is any of an alkyl group, a halogen group, an amine group, a nitro group and a cyano group. The substituent of the (b) aromatic cyclic group which may have a substituent is a chain or a cyclic alkyl group, a halogen group, an amine group, a nitro group, and a cyano group. The aromatic ring group of (b) is an aromatic hydrocarbon group or an aromatic heterocyclic group.

In the following general formulae (2-6) to (2-10), each of Ya and Yb independently represents (d) an aromatic cyclic group which may have a substituent. The substituent of the above (d) aromatic cyclic group which may have a substituent is a chain or a cyclic alkyl group, a halogen group, an amine group, a nitro group and a cyano group. The aromatic cyclic group of the above (d) is an aromatic hydrocarbon group or an aromatic heterocyclic group.

Further, the compound represented by the above formula (2-6) to (2-10) is an example of the compound of the present invention, and the technical scope of the present invention is not limited by these compounds.

The compound of the formula (1-1) contains a diaminobiphenyl group disposed between two dibenzofurans and two dibenzofurans, and has two two instead of two dibenzofurans. In the case of benzothiophene, the bonding position of the amine group bonded to the diaminobiphenyl group is not particularly limited. For example, it may be in the 5,5' position, such as the compound represented by the formula (2-6); it may be in the 4, 5' position, as in the compound represented by the formula (2-7); , 3' position, like the compound of the formula (2-8); can be 4, 3' position, like the compound of the formula (2-9); can be 5, 3' position, such as (2-10) The compound is the same as the compound shown in the formula (1-2).

The bonding position of the amine group bonded to the diaminobiphenyl group is preferably 5, 5' or 4, 4' from the viewpoint of ease of synthesis.

When the compound of the formula (1-1) contains a diaminobiphenyl group disposed between two dibenzofurans and two dibenzofurans, the substitution position of the two dibenzofurans may be 1~ Any of the four, and each can be different. The substitution position of the two dibenzofurans is preferably 2 or 4 from the viewpoint of the ease of synthesis of the compound.

(Organic EL device)

The organic EL device of the present invention is characterized in that a light-emitting layer and a hole transport layer disposed on the anode side of the light-emitting layer are provided between the cathode and the anode. The hole transport layer of the organic EL device of the present invention contains the compound of the present invention.

Fig. 1 is a schematic cross-sectional view for explaining an example of an organic EL device of the present invention. The organic EL element 1 shown in FIG. 1 has a laminated structure in which a first electrode 9 (anode), a hole injection layer 8, a hole transport layer 7, a light-emitting layer 6, and electron transport are sequentially formed on a substrate 2. Layer 5, electron injection layer 4, and second electrode 3 (cathode).

In the organic EL element 1 shown in Fig. 1, all of the laminated structures constituting the organic EL element formed on the substrate 2 are composed of an organic compound.

In addition, the organic EL element 1 shown in FIG. 1 may be a HOILED element, that is, a layer composed of an inorganic compound formed on the substrate 2 and constituting the organic EL element 1. In this case, for example, the organic EL element 1 shown in FIG. 1 is provided with an electron injecting layer 4 composed of an inorganic oxide and a hole injecting layer 8 composed of an inorganic oxide as an inorganic compound. The layer formed. Inorganic compounds are more stable than organic compounds. Therefore, the HOILED element is preferable in that it is resistant to oxygen and water as compared with the organic EL element which does not contain the layer which consists of an inorganic compound.

In addition, although the case where the electron injection layer 4 and the hole injection layer 8 are provided in the organic EL element 1 shown in FIG. 1 will be described as an example, for example, the electron injection layer 4 and/or the hole injection may not be provided. Layer 8. Further, in the organic EL element 1 shown in Fig. 1, an electron injecting layer composed of an inorganic compound may be provided instead of the electron injecting layer 4 composed of an organic compound, or a hole injecting layer composed of an inorganic compound may be provided instead of being organic. A hole injection layer 8 composed of a compound.

The organic EL element 1 shown in Fig. 1 may be of a top emission type (light extraction on the side opposite to the substrate 2 side) or a bottom emission type (light extraction on the side of the substrate 2).

In addition, the organic EL element 1 shown in FIG. 1 is a structure in which a forward structure of the first electrode 9 functioning as an anode is disposed between the substrate 2 and the light-emitting layer 6.

"substrate"

The material of the substrate 2 may, for example, be polyethylene terephthalate, polyethylene naphthalat, polypropylene, cycloolefin polymer, polyamine, polyether oxime, polymethyl methacrylate, A resin material such as a polycarbonate or a polyarylate, a glass material such as quartz glass or a soda glass, or the like, and one or more of them may be used.

When the organic EL element 1 uses a bottom emission type, the material of the substrate 2 uses a transparent material.

When the organic EL element 1 is a top emission type, the material of the substrate 2 is not only a transparent material but also an opaque material. The opaque substrate may, for example, be a substrate made of a ceramic material such as alumina, an oxide film (insulating film) formed on the surface of a metal substrate such as stainless steel, or a substrate made of a resin material.

The average thickness of the substrate 2 is preferably 0.1 to 30 mm, more preferably 0.1 to 10 mm. The average thickness of the substrate 2 can be measured by a digital multimeter and a cursor.

"First electrode (anode)"

The first electrode 9 in the organic EL element 1 shown in Fig. 1 functions as an anode and exhibits a fundamental energy. Examples of the material of the first electrode 9 include ITO (indium tin oxide), IZO (indium zinc oxide), FTO (fluorinated tin oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , Al-containing ZnO, and the like. Oxide, etc. Among them, as the material of the first electrode 9, ITO, IZO, and FTO are particularly preferably used.

The average thickness of the first electrode 9 is not particularly limited, but is preferably 10 to 500 nm, more preferably 100 to 200 nm.

The average thickness of the first electrode 9 can be measured by a probe type film thickness meter or a spectroscopic ellipsometer.

"hole injection layer"

The hole injection layer 8 in the present embodiment can be any compound which can be generally used as a material of the hole injection layer 8, and can be used in combination. Specifically, examples of the material of the hole injection layer 8 include PEDOT:PSS, anthocyanin (H ₂ Pc), and a metallocene-like metal or non-metal anthraquinone compound represented by the following formula (131). One or two or more of these may be used.

Further, when the hole injection layer 8 is made of an inorganic compound, it is preferably a layer made of an inorganic oxide such as a metal oxide layer. The metal oxide layer is not particularly limited, and for example, one or more of vanadium oxide (V ₂ O ₅ ), molybdenum oxide (MoO ₃ ), and ruthenium oxide (RuO ₂ ) may be used. Among these, the hole injection layer 8 is preferably a component mainly composed of vanadium oxide or molybdenum oxide.

When the hole injection layer 8 is mainly composed of vanadium oxide and/or molybdenum oxide, the function of injecting holes from the first electrode 9 (anode) and transporting it to the hole injection layer 8 of the light-emitting layer 6 or the hole transport layer 7 will be Become better. Further, vanadium oxide and molybdenum oxide are suitable for preventing a decrease in hole injection efficiency of the first electrode 9 toward the light-emitting layer 6 or the hole transport layer 7 due to high hole transportability.

The average thickness of the hole injection layer 8 is not particularly limited, but is preferably 1 to 1000 nm, more preferably 5 to 50 nm.

The average thickness of the hole injection layer 8 can be measured by a crystal vibrating film thickness gauge at the time of film formation.

"hole transport layer"

The hole transport layer 7 is disposed next to the light-emitting layer 6.

The hole transport layer 7 is composed of a compound represented by the above formula (1-1). Hole transport material. Therefore, the hole transport layer 7 is excellent in band gap energy and excellent in electrical/thermal stability. As a result, the organic EL element 1 shown in Fig. 1 has a long life and high luminous efficiency.

In particular, when the light-emitting layer 6 of the organic EL element 1 shown in FIG. 1 contains a host material composed of an electron transporting material or a two-charge transporting material and a guest material composed of a phosphorescent material, it will become a hole transporting property and A hole transport layer 7 having an excellent electron blocking property and an excitation energy of a triplet state (T ₁ ), a HOMO level, a LUMO level, and a band gap energy, and an appropriate value, can realize an organic EL element having high luminous efficiency. 1, very ideal.

More specifically, in the organic EL element 1 shown in Fig. 1, the host material of the light-emitting layer 6 uses an electron transporting material or a hole-electron transporting material which is described later. Therefore, the charge recombination region of the light-emitting layer 6 is immediately adjacent to the hole transport layer/light-emitting layer interface.

The organic EL element 1 shown in Fig. 1 can obtain a high degree of electron blocking property because the band gap energy of the hole transport layer 7 is large and the LUMO level is appropriate. Therefore, excess electrons supplied to the light-emitting layer 6 can be prevented from leaking from the light-emitting layer 6 to the hole transport layer 7 without being recombined with the holes. Therefore, in the organic EL element 1 shown in FIG. 1, it is possible to suppress a decrease in luminous efficiency due to leakage of electrons from the light-emitting layer 6 to the hole transport layer 7, and to improve the efficiency of the combination and obtain high luminous efficiency.

Further, the band gap energy of the hole transport layer 7 is preferably higher than the band gap energy of the host material of the light-emitting layer 6. When the band gap energy of the HOMO level-appropriate hole transport layer 7 is higher than the band gap energy of the host material of the light-emitting layer 6, the electron blocking property of the hole transport layer 7 becomes higher, and the supply to the light can be more effectively prevented. Excess electrons of layer 6 leak from the light-emitting layer 6 to the hole transport layer 7, so that the recombination efficiency Increased and achieved high luminous efficiency.

Further, the hole transporting layer 7 of the organic EL element 1 shown in Fig. 1 has a very high excitation triplet state (T ₁ ). Therefore, the organic EL element 1 shown in FIG. 1 can prevent the energy of the excited triplet state (T ₁ ) from moving from the light-emitting layer 6 to the hole transport layer 7, and the energy of exciting the triplet state (T ₁ ) can be enclosed in the light-emitting layer 6 . The effect inside. Therefore, when the luminescent material described later is a phosphorescent material, the excited state energy of the host material can be efficiently taken out as phosphorescence.

The average thickness of the hole transport layer 7 is not particularly limited, but is preferably 10 to 150 nm, more preferably 20 to 100 nm.

For example, the average thickness of the hole transport layer 7 can be measured by a probe type film thickness meter and a spectroscopic ellipsometer.

The hole transport layer 7 may be composed of only one layer as shown in FIG. 1, or may have one or more second holes on the side of the hole injection layer 8 of the hole transport layer 7 disposed next to the light-emitting layer 6. Transport layer (not shown).

As the hole transporting organic material for the second hole transport layer, various p-type polymer materials (organic polymers) can be used, or various p-type low molecular materials can be used singly or in combination.

Specifically, the material of the second hole transport layer may be, for example, N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'- Diamine (α-NPD), polyarylamine, fluorene-arylamine copolymer, fluorene-dithiophene copolymer, poly(N-vinylcarbazole), polyethylene fluorene, polyethylene fluorene, polythiophene, poly Alkylthiophene, polyhexylthiophene, poly(p-phenylene vinylene), poly(ethynylene vinylene) ), hydrazine formaldehyde resin, ethyl carbazole formaldehyde resin or its derivatives. The material of the second hole transport layer can also be used as a mixture with other compounds. As an example, a mixture containing polythiophene can be exemplified by poly(3,4-extended ethyl group) represented by the formula (131). Oxythiophene/styrenesulfonic acid) (PEDOT: PSS) and the like.

The average thickness of the second hole transport layer is not particularly limited, but is preferably 10 to 150 nm, more preferably 20 to 100 nm.

For example, the average thickness of the second hole transport layer can be measured by a probe type film thickness meter and a spectroscopic ellipsometer.

"Lighting layer"

The light-emitting layer 6 is composed of a host material that is subjected to charge transport/recombination work and a guest material composed of a light-emitting material.

The host material uses an electron transporting material or a second charge transporting material of a hole and an electron. Specifically, examples of the electron transporting host material include Bepp 2 represented by the following formula (132), a compound represented by the following formula (133) to (137), and the like. Bepp2 shown in formula (132) is preferred.

By using a metal complex of Bepp2 or the like as the host material, energy transfer from the host material to the guest material can be efficiently performed, and the organic EL element 1 having high luminous efficiency can be obtained.

Further, examples of the charge-transporting host material of the hole and the electron include compounds represented by the following formulas (139) to (160).

Phosphorescent materials should be used for the guest material.

Examples of the phosphorescent material include green to red phosphorescent materials represented by the following general formulae (161) to (189). By using a phosphorescent material as a guest material, it will become an organic EL device that utilizes phosphorescence. Result, use with guest materials Compared with the organic EL element of the fluorescent material, the luminous efficiency is improved, which is ideal.

The guest material content in the light-emitting layer 6 is preferably 1% by weight or more and Less than 15% by weight. By making the content of the guest material in the light-emitting layer 6 the above-mentioned range In addition, more excellent luminous efficiency can be obtained. When the content of the guest material in the light-emitting layer 6 is less than the above range, the energy movement from the host material to the guest material cannot sufficiently occur, and the host material itself emits light and the luminous efficiency is lowered. Further, when the content of the guest material in the light-emitting layer 6 exceeds the above range, the electron transport property of the host material becomes insufficient, and the light-emitting region is moved away from the interface of the hole transport layer 7 of the light-emitting layer 6 by the charge of the guest material, and the light-emitting efficiency is improved. Reduce the embarrassment.

The average thickness of the light-emitting layer 6 is not particularly limited, but is preferably 10 to 150 nm, more preferably 20 to 100 nm.

The average thickness of the light-emitting layer 6 can be measured by a probe type film thickness meter, or can be measured by a crystal vibrating film thickness when the light-emitting layer 6 is formed.

"Electronic transport layer"

The material for the electron transport layer 5 may, for example, be a phosphine oxide derivative such as Phenyl-dipyrenyl phosphine oxide (POPy2), such as gin-1,3,5-(3'-( a pyridine derivative such as pyridine-3"-yl)phenyl)benzene (TmPyPhB), a quinoline derivative such as (2-(3-(9-oxazolyl)phenyl)quinoline (mCQ)), Pyrimidine derivatives such as 2-phenyl-4,6-bis(3,5-dipyridylphenyl)pyrimidine (BPyPPM), pyridyl a derivative such as a phenanthroline derivative such as 2,4-bis(4-biphenyl)-6-(4'-(2-pyridyl)-4-biphenyl )-[1,3,5]3 (MPT) a derivative, a triazole derivative such as 3-phenyl-4-(1'-naphthyl)-5-phenyl-1,2,4-triazole (TAZ), An azole derivative such as 2-(4-biphenyl)-5-(4-t-butylphenyl-1,3,4- Diazole) (PBD) An oxadiazole derivative, an imidazole derivative such as 2,2',2"-(1,3,5-phenylene)-parade (1-phenyl-1-H-benzimidazole) (TPBI), An aromatic ring tetracarboxylic anhydride such as naphthalene or anthracene, bis[2-(2-hydroxyphenyl)benzothiazole chelate] zinc (Zn(BTZ) ₂ ), ginseng (8-hydroxyquinoline) aluminum (Alq3) 2,5-bis(6'-(2',2"-dipyridyl))-1,1-dimethyl-3,4-diphenylcarbazole, represented by various metal complexes (Organic decane derivative represented by a carbazole derivative such as (PyPySPyPy)), and one or more of these may be used. Among the materials of the electron transport layer, a phosphine oxide derivative such as POPy ₂ , a metal complex such as Alq ₃ , and a pyridine derivative such as TmPyPhB are preferably used.

The average thickness of the electron transport layer 5 is not particularly limited, but is preferably 10 to 150 nm, more preferably 20 to 100 nm.

The average thickness of the electron transport layer 5 can be measured by a probe type film thickness meter and a spectroscopic ellipsometer.

"electron injection layer"

When the material composed of the organic compound is provided as the electron injecting layer 4, any compound generally used as a material of the electron injecting layer may be used, or these may be used in combination. Specifically, for example, polyethylenimine, poly(9,9-bis(6"-trimethylammoniumhexyl)fluorene-co-alt-phenyl) having a bromine counter ion (ie, poly(9,9) ' -bis(6 " -N,N,N-trimethylammoniumhexyl)-fluorene-co-alt-phenylene) with bromide counterions, FPQ-Br), poly(9,9-bis(3'-dimethylamino) Propyl) 2,7-fluorene-alt-2,7-(9,9-dioctylfluorene) (PFNR ² ), polyalkylene oxide, and the like.

Further, when the electron injecting layer 4 is composed of an inorganic compound, it is preferably a layer made of an inorganic oxide such as a metal oxide layer. The metal oxide layer is not particularly limited, and for example, titanium oxide (TiO ₂ ), zinc oxide (ZnO), tungsten oxide (WO ₃ ), cerium oxide (Nb ₂ O ₅ ), iron oxide (which may be used) may be used. One or two or more kinds of Fe ₂ O ₃ ), tin oxide (SnO ₂ ), magnesium oxide (MgO), cerium oxide (HfO ₂ ), zirconium oxide (ZrO ₂ ), and indium gallium zinc oxide (IGZO). The electron injecting layer 4 composed of such a metal oxide layer functions as an electron injecting layer and an electrode (cathode).

Further, the material of the electron injecting layer 4 is not limited to the above materials, and for example, LiF or the like can also be used.

The average thickness of the electron injecting layer 4 is not particularly limited, but is preferably 1 to 1000 nm, more preferably 2 to 100 nm.

The average thickness of the electron injecting layer 4 can be measured by a probe type film thickness meter and a spectroscopic ellipsometer.

"Second electrode (cathode)"

The second electrode 3 of the organic EL element 1 shown in Fig. 1 functions as a cathode. The second electrode 3 may, for example, be Au, Pt, Ag, Cu, Al or an alloy containing the same. Among them, Au, Ag, and Al are particularly preferably used for the second electrode 3.

The average thickness of the second electrode 3 is not particularly limited, but is preferably 10 to 1000 nm, more preferably 30 to 150 nm. Further, when the second electrode 3 is made of a material that is impermeable, for example, the average thickness thereof can be set to about 10 to 30 nm, whereby it can be used as an anode of a top emission type and a transparent type.

The average thickness of the second electrode 3 can be measured by the crystal vibrating film thickness when the second electrode 3 is formed.

The organic EL device 1 of the present embodiment shown in Fig. 1 can be produced by a conventional method as appropriate.

The organic EL element 1 of the present embodiment is applied to the first electrode 9 (anode) The light-emitting layer 6 and the hole transport layer 7 disposed on the first electrode 9 side of the light-emitting layer 6 are provided between the second electrode 3 (cathode), and the hole transport layer 7 is represented by the above formula (1-1). The compound will have a hole transporting layer with a large band gap energy and excellent electrical/thermal stability, and will be a long-life and high luminous efficiency component.

(other examples)

Fig. 2 is a schematic cross-sectional view for explaining another example of the organic EL device of the present invention. The organic EL element 1A shown in FIG. 2 has the first electrode 9, the electron injection layer 4, the electron transport layer 5, the light-emitting layer 6, the hole transport layer 7, the hole injection layer 8, and the second layer sequentially formed on the substrate 2. The laminated structure of the electrode 3.

In the organic EL element 1A shown in FIG. 2, the first electrode 9 functions as a cathode, and the second electrode 3 functions as an anode.

In the organic EL element 1A shown in FIG. 2, a first electrode 9 functioning as a cathode is formed on the substrate 2, and this element is a structure in which the reverse structure of the first electrode 9 is disposed between the substrate 2 and the light-emitting layer 6.

The difference between the organic EL element 1A shown in FIG. 2 and the organic EL element 1 shown in FIG. 1 is only the order of lamination of the electron injection layer 4, the electron transport layer 5, the light-emitting layer 6, the hole transport layer 7, and the hole injection layer 8. in contrast. Therefore, members of the organic EL element 1A shown in FIG. 2 that are the same as those of the organic EL element 1 shown in FIG. 1 are denoted by the same reference numerals, and their description will be omitted.

Further, the organic EL device of the present invention is not limited to the organic EL device shown in Figs. 1 and 2 . In other words, the organic EL device of the present invention needs only to have the light-emitting layer 6 between the first electrode 9 (anode) and the second electrode 3 (cathode) and the hole transporting on the side of the first electrode 9 of the light-emitting layer 6. The layer 7 and the hole transport layer 7 may contain the compound represented by the above formula (1-1), the electron injection layer 4, and electron transport. The layer 5, the second hole transport layer, and the hole injection layer 8 may be formed as needed.

Further, the organic EL device of the present invention may further have other layers between the layers shown in Figs. 1 and 2 .

The organic EL device of the present invention may be based on reasons such as further improving the characteristics of the organic EL device, and may have, for example, a hole blocking layer and an electronic device layer.

The materials from which such layers are formed may be materials which are generally used to form the layers. In addition, methods of forming such layers can use methods that are generally used to form such layers.

In the organic EL device of the present invention, the luminescent color can be changed by appropriately selecting the material of the organic compound layer, or a desired color can be obtained by using a color filter or the like in combination. Therefore, it can be suitably used as a light-emitting portion of a display device and a lighting device. For example, a display device using the organic EL element of the present invention having a display panel and a driving circuit for driving the display panel can be fabricated, and has a long life as a display panel and high luminous efficiency.

Further, the above embodiment is illustrative of a case where the compound of the present invention is used as a hole transporting material of a hole transporting layer, but for example, the compound of the present invention can also be used for a hole injecting layer in an organic EL device. And the host material when the guest material is a phosphorescent material, etc., and can also be used for a hole transporting material of an organic solar cell.

Example

"Synthesis of Compounds"

(Synthesis Example 1)

The compound of the formula (1-83) was synthesized by the following method.

N-(4-chloro-3-methylphenyl)-N-dibenzo[b,d]thiophen-4-amine represented by the above formula (1-192) was synthesized by the following method.

5.79 g (22.0 mmol) of 4-bromodibenzothiophene represented by the above formula (1-190) and 4-chloro-3-methylaniline of the above formula (1-191) in an argon atmosphere: 3.74 g (26.4 mmol), 3.70 g (33.0 mmol) of potassium third butoxide, 99 mg (0.44 mmol) of palladium (II) acetate and 60 mL of dehydrated toluene were placed in a 150 mL Schlenk tube equipped with a stirring member. And degas. Thereafter, 267 mg (1.32 mmol) of tri-tert-butylphosphine was added and the plug was tightly stirred, and the mixture was stirred at 100 ° C for 10 hours. Time.

After cooling to room temperature, the reaction mixture was added to water, extracted with dichloromethane and washed with water. After the organic layer was dried over anhydrous sodium sulfate, the solvent was evaporated. The obtained crude product was purified by cerium oxide gel column chromatography using hexane: dichloromethane (4:1) as an eluent.

By carrying out the above procedure, the compound of the above formula (1-192) was obtained in a yield of 3.75 g and a yield of 53%. The identification of the compound was carried out by mass spectrometry to confirm that the molecular ion spike coincided with the target.

Next, N-(4-chloro-3-methylphenyl)-N-phenyldibenzo[b,d]thiophen-4-amine represented by the above formula (1-194) was synthesized by the following method.

N-(4-chloro-3-methylphenyl)-N-dibenzo[b,d]thiophen-4-amine represented by the above formula (1-192) in an argon atmosphere, 3.56 g (11.0) Ment), 2.69 g (13.2 mmol) of iodobenzene represented by the above formula (1-193), 1.85 g (16.5 mmol) of potassium third butoxide, 49 mg (0.22 mmol) of palladium (II) acetate, and 30 mL of dehydrated toluene Into a 100 mL Schlenk tube with a stirrer and degas. Thereafter, 134 mg (0.66 mmol) of tri-tert-butylphosphine was added and the plug was tightly stirred, and the mixture was stirred at 100 ° C for 10 hours.

After cooling to room temperature, the reaction mixture was added to water, extracted with dichloromethane and washed with water. After the organic layer was dried over anhydrous sodium sulfate, the solvent was evaporated. The obtained crude product was purified by cerium oxide gel column chromatography using hexane: dichloromethane (6:1) as an eluent.

By carrying out the above procedure, the compound of the above formula (1-194) was obtained in a yield of 3.79 g and a yield of 86%. The identification of the compound was carried out by mass spectrometry to confirm that the molecular ion spike coincided with the target.

Next, N,N-bis(dibenzo[b,d]thiophen-4-yl)-2,2'-dimethyl-[1, represented by the above formula (1-83) was synthesized by the following method. 1'-biphenyl]-4,4'-diamine.

Bis(1,5-cyclooctadiene)nickel (0) 5.17 g (18.8 mmol), 2,2'-bipyridine 2.94 g (18.8 mmol), 1,5-cyclooctadiene under argon atmosphere 2.03 g (18.8 mmol) and DMF 20 mL were placed in a 150 mL Schlenk tube equipped with a stirring member and tightly sealed, and stirred at 60 ° C for 30 minutes, and then cooled to room temperature.

Thereafter, the Schlenk tube was opened under an argon atmosphere, and N-(4-chloro-3-methylphenyl)-N-benzene represented by the above formula (1-194) dissolved in 50 mL of THF was further added. 3.76 g (9.40 mmol) of bisbenzo[b,d]thiophen-4-amine was stirred at 80 ° C for 15 hours.

After cooling to room temperature and distilling off the solvent, the reaction mixture dissolved in dichloromethane was poured into water, extracted with dichloromethane, and washed with water. After the organic layer was dried over anhydrous sodium sulfate, the solvent was evaporated. The obtained crude product was purified by cerium oxide gel column chromatography using hexane: dichloromethane (5:1) as an eluent.

By carrying out the above procedure, an object having an HPLC purity of 98.5% was obtained in a yield of 3.01 g and a yield of 88%. After that, the obtained product was washed with acetone, and recrystallized by toluene was further produced, and the compound of the above formula (1-83) having an HPLC purity of 99.9% was obtained at a yield of 1.55 g and a recovery of 51%. .

The purity measurement by HPLC was carried out under the conditions shown below.

Column "InertSustain, C18, 5μm, 4.6mm × 150mm (reverse phase ")), the solution "acetonitrile: THF = 90:10", the flow rate "1.0 ml / min", Uv detector "254 nm".

The identification of the compound was carried out by mass spectrometry to determine that the molecular ion spike coincided with the target and ¹ H-NMR (Nuclear Magnetic Resonance).

¹ H-NMR, CDCl ₃ δ 1.98 (s, 6H), 6.89-7.00 (m, 8H), 7.08 (d, J = 8.2 Hz, 4H), 7.22-7.00 (m, 4H), 7.31-7.45 ( m, 8H), 7.7 (d, J = 7.3 Hz, 2H), 7.98 (d, J = 7.8 Hz, 2H), 8.13 (d, J = 7.3 Hz, 2H)

(Synthesis Example 2)

The compound of the formula (1-83) is synthesized by the following method different from the above method.

The compound of the above formula (1-196) was synthesized by the following method.

The 4-bromodibenzothiophene (13.16 g, 50 mmol) represented by the above formula (1-190) and the above formula (1-195) were placed in a 300 mL Schlenk tube provided with a stirring member and replaced with argon. Aniline (4.66 g, 50 mmol), palladium acetate (225 mg, 1.0 mmol), toluene (150 mL), tri-tert-butylphosphine (202 mg, 1.0 mmol), and potassium tributoxide (5.61 g, 50 mmol) were sealed and stirred at 100 ° C for 10 hours.

Thereafter, the reaction vessel was allowed to cool to near room temperature, and the lid was opened and water (150 mL) was placed therein. After the contents were transferred to a separatory funnel to separate the organic phase from the aqueous phase, the aqueous phase was removed and the organic phase was further washed with water. The organic phase was dried over sodium sulfate. Thereafter, sodium sulfate was removed by filtration, and the organic phase was concentrated. Further, the resulting mixture is purified by cerium oxide gel column chromatography (developing solvent: hexane/dichloromethane = 3/1) to obtain the compound of the above formula (1-196). The yield was 10.7 g, and the yield was 77.8%).

Identification of the compounds was carried out using ¹ H-NMR.

¹ H-NMR, DMSO-d ₆ , δ: 6.85 (t, J = 7.3 Hz, 1H), 6.98 (d, J = 7.8 Hz, 8H), 7.23 (t, J = 8.3 Hz, 2H), 7.32 ( d, J = 7.8 Hz, 1H), 7.45 (t, J = 7.8 Hz, 1H), 7.50 - 7.53 (m, 2H), 8.01 - 8.03 (m, 2H), 8.17 (s, 1H), 8.33 - 8.35 (m, 1H)

Next, the compound of the above formula (1-83) was synthesized by the method shown below.

The compound represented by the above formula (1-196) (2.11 g, 8.0 mmol) and the above formula (1-197) 4, 4 were placed in a 100 mL Schlenk tube equipped with a stirring member and replaced with argon. '-Diiodo-2,2'-dimethyl-1,1'-biphenyl (1.74 g, 4.0 mmol), palladium acetate (36 mg, 0.16 mmol), toluene (50 mL), tri-tert-butylphosphine ( 32 mg, 0.16 mmol) and potassium butoxide (0.90 g, 8.0 mmol) were stirred, and then stirred at 100 ° C for 10 hours.

After that, let the reaction vessel cool to near room temperature, open the lid and Water (50 mL) was placed therein. The contents were transferred to a separatory funnel to separate the organic phase from the aqueous phase, the aqueous phase was removed and the organic phase was further washed with water. The organic phase was dried over sodium sulfate. Thereafter, sodium sulfate was removed by filtration, and the organic phase was concentrated. The obtained mixture was concentrated and purified by silica gel column chromatography (developing solvent: hexane/dichloromethane = 3/1) to obtain the compound of the above formula (1-83). The yield was 2.40 g and the yield was 82.3%.

(Synthesis Example 3)

The compound represented by the following formula (1-202) was synthesized by the method shown below.

2,2'-dimethyl-1,1'-biphenyl represented by the above formula (1-199) was synthesized by the method shown below.

A solution of 2-bromotoluene (11.97 g, 70.0 mmol) in diethyl ether (140 mL) of the above formula (1-198) was adjusted in a four-necked flask equipped with a stirring apparatus under an argon atmosphere, and cooled to -15. °C. After 1.6 M (mole/L) of n-butyllithium (45 mL, 72 mmol) was added, the mixture was stirred for 2 hours. Thereafter, trimethyl borate (7.27 g, 70.0 mmol) was added, and the mixture was stirred for 20 hours while gradually raising the temperature to room temperature (rt). Water was added to the reaction solution to stop the reaction, and ether and hexane were removed under reduced pressure.

The cooling tube was placed in a reaction vessel, and the inside of the vessel was again subjected to argon replacement. Thereafter, 2-bromotoluene (11.97 g, 70.0 mmol), decyltriphenylphosphine palladium (0.809 g, 0.7 mmol), potassium carbonate (9.67 g, 70 mmol), and toluene (70 mL) were added, and then water was further added to make toluene and water. The same amount. Thereafter, the mixture was stirred at 100 ° C for 20 hours.

The reaction solution was transferred to a separatory funnel to separate the organic phase from the aqueous phase, and the extraction was carried out with an ether. The organic phase was dried over sodium carbonate, filtered, concentrated, and the compound of the above formula (1-199) was separated by cerium dioxide gel column chromatography (developing solvent: hexane). Identification of the target was performed by GCMS. The yield was 7.84 g and the yield was 61%.

Next, 4-bromo-2,2'-dimethyl-1,1'-biphenyl represented by the above formula (1-200) was synthesized by the following method.

The titration funnel was placed in a four-necked flask equipped with a stirring member, and after the container was subjected to argon replacement, 2,2'-dimethyl-1,1'- represented by the above formula (1-199) was charged. A solution of biphenyl (5.47 g, 30.0 mmol) in dichloromethane (90 mL) and zirconium chloride (0.35 g, 1.5 mmol) was cooled to -15 °C.

NBS (5.34 g, 30.0 mmol) was charged into the titration funnel. A solution of DMF (30 mL) was titrated in small portions. After all titration, the temperature was gradually raised and stirred at room temperature (rt) for 48 hours. After adding water to the reaction solution, dichloromethane was removed under reduced pressure, and the title compound was extracted with diethyl ether. The organic phase was dried over sodium sulfate, filtered and concentrated, and then the above-mentioned formula (1-200) was separated by cerium dioxide gel column chromatography (developing solvent: hexane/dichloromethane = 3/1). Show the object. The yield was 5.09 g and the yield was 65%.

Next, N4,N4'-bis(dibenzo[b,d]thiophen-4-yl)-2,2'-dimethyl- represented by the above formula (1-201) was synthesized by the method shown below. [1,1'-biphenyl]-4,4'-diamine.

After argon replacement of a 200 mL Schlenk tube equipped with a stirring member, bis(1,5-cyclooctadiene)nickel (0) (10.0 g, 36.4 mmol) and 2,2'-bipyridine (5.68 g) were added. , 36.4 mmol) and THF (100 mL) and stirred for 45 min. Thereafter, N-(4-chloro-3-methylphenyl)-N-dibenzo[b,d]thiophen-4-amine represented by the above formula (1-192) (2.59 g, 8.0 mmol) was further added. A solution of THF (20 mL) was stirred at 65 ° C for 24 hours.

Thereafter, water was added to the reaction solution, and the mixture was washed with dichloromethane to carry out filtration through diatomaceous earth. The resulting filtrate was concentrated to the extent that THF could be removed. The object was extracted from the solution with dichloromethane. The obtained organic phase was dried over sodium sulfate, filtered and concentrated. Thereafter, the object of the above formula (1-201) was isolated by cerium oxide gel column chromatography (developing solvent: hexane/dichloromethane = 1/1). The yield was 0.55 g and the yield was 12%.

Next, N4,N4'-bis(dibenzo[b,d]thiophen-4-yl)-N4,N4'-bis (2, represented by the above formula (1-202) was synthesized by the method shown below. 2'-Dimethyl-[1,1'-biphenyl]-4-yl)-2,2'-dimethyl-[1,1'-biphenyl]-4,4'-di amine.

The Schlenk tube provided with the stirrer is subjected to argon substitution, and is charged with N4,N4'-bis(dibenzo[b,d]thiophen-4-yl)-2 represented by the above formula (1-201). 2'-Dimethyl-[1,1'-biphenyl]-4,4'-diamine (0.5 g, 0.89 mmol), 4-bromo-2,2' represented by the above formula (1-200) -Dimethyl-1,1'-biphenyl (0.56 g, 0.22 mmol), palladium acetate (9 mg, 0.04 mmol), toluene (50 mL), tri-tert-butylphosphine (8 mg, 0.04 mmol) and third Potassium oxychloride (0.22 g, 2.0 mmol) was stirred at 100 ° C for 6 hours.

Then, water was added to make the reaction, and extraction was carried out with diethyl ether. The organic phase was dried over sodium sulfate, filtered and concentrated. Thereafter, the object of the above formula (1-202) was isolated by ruthenium dioxide gel column chromatography (developing solvent: hexane / dichloromethane = 2 / 1).

(Synthesis Example 4)

The compound of the formula (1-107) was synthesized by the method shown below.

The above formula (1-204) was synthesized by the method shown below. Compound.

2-Bromodibenzothiophene (13.16 g, 50 mmol) represented by the above formula (1-203), and the above formula (1-195) were placed in a 300 mL Schlenk tube equipped with a stirring member and replaced with argon. Aniline (4.66 g, 50 mmol), palladium acetate (225 mg, 1.0 mmol), toluene (150 mL), tri-tert-butylphosphine (202 mg, 1.0 mmol) and potassium butoxide (5.61 g, 50 mmol) Seal it. Thereafter, the mixture was stirred at 100 ° C for 18 hours.

Thereafter, the reaction vessel was allowed to cool to near room temperature, and the lid was opened and water (150 mL) was placed therein. The contents were transferred to a separatory funnel to separate the organic phase from the aqueous phase, the aqueous phase was removed and the organic phase was further washed with water. The organic phase was dried over sodium sulfate. Thereafter, sodium sulfate was removed by filtration, and the organic phase was concentrated. The resulting mixture was purified by silica gel column chromatography (developing solvent: hexane/dichloromethane = 3/1) to obtain the compound of the above formula (1-204). The yield was 7.85 g and the yield was 57.1%. The synthesized compound was identified using a MS (Mass Spectrum) pattern.

Next, the compound of the above formula (1-107) was synthesized by the following method.

The compound of the above formula (1-204) (2.11 g, 8.0 mmol) and the above formula (1-197) 4, 4 were placed in a 100 mL Schlenk tube equipped with a stirring member and replaced with argon. '-Diiodo-2,2'-dimethyl-1,1'-biphenyl (1.74 g, 4.0 mmol), palladium acetate (36 mg, 0.16 mmol), toluene (50 mL), tri-tert-butylphosphine ( 32 mg, 0.16 mmol) and potassium t-butoxide (0.90 g, 8.0 mmol) were sealed. Thereafter, the mixture was stirred at 100 ° C for 18 hours.

After that, let the reaction vessel cool to near room temperature, open the lid and Water (50 mL) was placed therein. The contents were transferred to a separatory funnel to separate the organic phase from the aqueous phase, the aqueous phase was removed and the organic phase was further washed with water. The organic phase was dried over sodium sulfate. Thereafter, sodium sulfate was removed by filtration, and the organic phase was concentrated. The resulting mixture was purified by silica gel column chromatography (developing solvent: hexane/dichloromethane = 3/1) to give the desired compound of the above formula (1-107). The yield was 2.32 g and the yield was 79.6%.

(Synthesis Example 5)

The compound represented by the following formula (1-95) was synthesized by the method shown below.

The compound of the above formula (1-207) was synthesized by the method shown below.

The 2-methyl-2-bromo-4-chlorobenzene (5.02 g, 20.0 mmol) represented by the above formula (1-205) and the second were placed in a 200 mL Schlenk tube equipped with a stirrer and replaced with argon. Diethyl ether (50 mL) was stirred and cooled to -15 °C. A 1.6 M (mol/L) n-butyllithium ‧ solution (13.0 mL, 20.5 mmol) was titrated. After stirring for 1 hour, trimethyl borate (2.13 g, 20.5 mmol) was added, and the mixture was stirred for 20 hours while warming from -15 ° C to room temperature to obtain the above formula (1-206). Show compound.

A small amount of distilled water (20 mL) was gradually added to stop the reaction, and diethyl ether and hexane were removed under reduced pressure. A cooling tube was installed, and the vessel was again subjected to argon replacement, and then distilled water (30 mL), 1-methyl-2-bromo-4-chlorobenzene (5.23 g, 20.5 mmol), and triphenylphosphine palladium (0.462 g, 0.40 mmol), potassium carbonate (2.76 g, 20 mmol) and toluene (100 mL) were refluxed for 20 hr.

After cooling to room temperature, the contents were transferred to a separatory funnel to separate the organic phase from the aqueous phase, the aqueous phase was removed and the organic phase was further washed with water. The organic phase was dried over sodium sulfate. Thereafter, sodium sulfate was removed by filtration, and the organic phase was concentrated. The obtained mixture was purified by silica gel column chromatography (developing solvent: hexane) to obtain the compound of the above formula (1-207). The yield was 4.14 g and the yield was 82.4%.

The identification of the compounds was carried out using ¹ H-NMR.

¹ H-NMR, DMSO-d ₆ , δ: 1.98 (s, 6H), 7.14 (s, 2H), 7.35 (d, J = 1.8 Hz, 4H)

Next, the compound of the above formula (1-95) was synthesized by the method shown below.

The compound represented by the above formula (1-196) (1.65 g, 6.0 mmol) and the compound of the above formula (1-207) (0.753) were placed in a 100 mL Schlenk tube equipped with a stirring member and replaced with argon. g, 3.0 mmol), palladium acetate (27 mg, 0.12 mmol), toluene (40 mL), tri-tert-butylphosphine (24 mg, 0.12 mmol), and potassium t-butoxide (0.673 g, 6.0 mmol), and sealed. Stir at 100 ° C for 10 hours.

After that, let the reaction vessel cool to near room temperature, open the lid and Water (40 mL) was placed therein. The contents were transferred to a separatory funnel to separate the organic phase from the aqueous phase, the aqueous phase was removed and the organic phase was further washed with water. The organic phase was dried over sodium sulfate. Thereafter, sodium sulfate was removed by filtration, and the organic phase was concentrated. The obtained mixture was concentrated and purified by silica gel column chromatography (developing solvent: hexane/dichloromethane = 3/1) to obtain the compound of the above formula (1-95). The yield was 1.85 g and the yield was 84.6%.

The identification of the compounds was carried out using ¹ H-NMR.

¹ H-NMR, DMSO-d ₆ , δ: 1.88 (s, 6H), 6.59 (d, J = 2.7 Hz, 2H), 6.85 (dd, J = 2.3 Hz, 8.2 Hz, 2H), 6.92 (d, J=7.3 Hz, 4H), 6.98 (t, J=7.3 Hz, 2H), 7.13 (d, J=8.2 Hz, 2H), 7.21-7.25 (m, 6H), 7.45-7.52 (m, 6H), 7.86 (dd, J = 1.8 Hz, 6.9 Hz, 2H), 8.19 (d, J = 7.8 Hz, 2H), 8.36 (dd, J = 1.4 Hz, 7.3 Hz, 2H)

(Synthesis Example 6)

The compound of the formula (2-85) was synthesized by the method shown below.

(synthesis of diphenylamine)

The diphenylamine represented by the above formula (2-198) was synthesized by the method shown below.

A 30 mL two-necked flask equipped with a stirring member was charged with nitrosobenzene (0.46 g, 4.3 mmol, 1.0 eq, molecular weight 107.11) represented by the above formula (2-197) and copper chloride (0.43 g, 4.3 mmol, 1.0 eq), after replacement with nitrogen, anhydrous N,N-dimethylformamide (5.3 mL) was added at an oil bath temperature of 55 ° C. Stir under heating for 40 minutes. Next, 4-dibenzofuran boronic acid (1.00 g, 4.7 mmol, 1.1 eq) represented by the above formula (2-196) was added, and the mixture was replaced with nitrogen, and stirred at the same temperature for 4.5 hours.

The reaction solution was cooled to room temperature, and water and diethyl ether were added, and the aqueous layer was separated from the organic layer, and further extracted with diethyl ether. Next, all the organic layers were combined and dehydrated using anhydrous magnesium sulfate. Thereafter, anhydrous magnesium sulfate was removed by filtration, and the solvent in the filtrate was distilled off under reduced pressure to obtain a residue containing the title compound.

The residue was purified by silica gel chromatography (yield: diethyl ether / hexane = 1/4) to afford 0.66 g of pale yellow solid.

The pale yellow solid obtained was investigated by NMR and found to contain many impurities. Therefore, re-purification of the pale yellow solid was carried out in the manner shown below. Specifically, the mixture was dissolved in diethyl ether (39 mL) while heating to a pale yellow solid in a warm bath of 45 ° C, and then hexane (50 mL) was stirred under stirring at room temperature, and then allowed to stand overnight in a refrigerator to precipitate a solid. Then, the precipitated solid was suction-filtered to obtain 0.07 g of a white solid. The white solid obtained was investigated by NMR and found to be an impurity.

In addition, the solvent contained in the filtrate from which the white solid was removed was distilled off under reduced pressure, and the mixture was dissolved in hexane (20 mL) while heating in a warm bath at 60 ° C, and the mixture was stirred at room temperature to precipitate a solid. Thereafter, the precipitated solid was suction-filtered to obtain 0.33 g of a white solid. The white solid was investigated by NMR, and the impurities were not completely removed.

Therefore, it is purified by cerium oxide gel chromatography (developing solvent: dichloromethane/hexane = 1/9) to obtain a diphenylamine represented by the above formula (2-198) of the object. White solid 0.27 g (1.1 mmol, yield 25%).

(Synthesis of Furan Derivatives for Organic EL)

The compound of the above formula (2-85) was synthesized by the method shown below.

The diphenylamine represented by the above formula (2-198) (0.52 g, 2.0 mmol, 3.2 eq) obtained by the above method was placed in an eggplant-shaped flask having a capacity of 50 mL, and the above formula (2-199) was shown. 4,4'-diiodo-2,2'-dimethylbiphenyl (0.27 g, 0.63 mmol, 1.0 eq, molecular weight 434.05), palladium (II) acetate (0.01 g, 0.05 mmol, 0.07 eq), three Tributylphosphine (0.030 mL, 0.13 mmol, 0.20 eq) and potassium t-butoxide (0.28 g, 2.5 mmol, 4.0 eq) were subjected to a reduced pressure nitrogen exchange for five times. Next, anhydrous toluene (12 mL) was added to the eggplant-shaped flask, and the mixture was heated and stirred at an oil bath temperature of 100 ° C for 3 hours to obtain a reaction liquid. Thereafter, it was confirmed by thin layer chromatography (TLC) that the starting material had disappeared from the reaction liquid.

Next, the reaction liquid was cooled to room temperature, and water (50 mL) was added and diluted with diethyl ether (50 mL), and filtered over Celite. The filtrate was extracted twice with diethyl ether (50 mL) and filtered. Dehydration. Thereafter, anhydrous magnesium sulfate was removed by filtration, and the solvent in the filtrate was distilled off under reduced pressure. As a result, 0.66 g of a residue containing the objective substance was obtained in the form of tea green amorphous crude.

The crude product thus obtained is purified by cerium oxide gel chromatography (developing solvent: dichloromethane/hexane = 1/4) to obtain the compound of the above formula (2-85). White solid 0.35 g (0.50 mmol, yield 79%).

The identification of the compound represented by the above formula (2-85) was carried out using ¹ H-NMR.

¹ H-NMR (500 MHz DMSO-d ₆ ), δ: 8.16 (dd, 2H, J = 7.5 Hz, 0.5 Hz), 8.00 (dd, 2H, J = 7.5 Hz, 1.0 Hz), 7.51 (d, 2H, J = 8.0 Hz), 7.47 (dt, 2H, J = 7.5 Hz, 1.5 Hz), 7.43 - 7.38 (m, 4H), 7.31 - 7.27 (m, 6H), 7.02 (dd, 8H, J = 8.0 Hz, 5.0 Hz), 6.95 (d, 2H, J = 2.5 Hz), 6.83 (dd, 2H, J = 8.0 Hz, 2.5 Hz), 1.95 (s, 6H).

"Cave transport layer material"

A film composed of the compound represented by the above formula (2-85) (Experimental Example 6) was produced, and the compound was synthesized using the above (Synthesis Example 6). Further, a film composed of the compound represented by the above formula (1-83) (Experimental Example 1) was produced, and the compound was synthesized using the above (Synthesis Example 1). Further, a film composed of DBTPB represented by the above formula (5) was produced.

Next, with respect to the film of the experimental example 1, the experimental example 6, and the DBTPB, the excitation light source of the wavelength of 300 nm was measured using the FluoroMax-4 by HORIBA, and the luminescence of the full-time area was measured at room temperature by setting without delay. spectrum. Fluorescence can be observed at room temperature. Therefore, knowledge of the excitation singlet (S ₁ ) (band gap) energy of each film can be obtained from the results of luminescence spectroscopy at room temperature. The results are shown in Figure 3.

Fig. 3 is a graph showing the results of luminescence spectrometry of a film of Experimental Example 1, a film of Experimental Example 6, and a film of DBTPB at room temperature.

As shown in FIG. 3, Experimental Example 6 exhibited a broad band gap compared to Experimental Example 1 and DBTPB.

It is presumed that the experimental example 6 composed of the compound represented by the above formula (2-85) and the experimental example 1 composed of the compound represented by the general formula (1-83) are diaminobiphenyl groups of the central skeleton of the molecular structure. The planarity has been disintegrated by the methyl group, and the π-conjugated system is cut off to become wider than the DBTPB.

In addition, it is speculated that the π-conjugated dibenzofuran has a smaller amplification than the dibenzothiophene, and therefore, a diaminobiphenyl group is disposed between the two dibenzothiophenes. In Experimental Example 1 in which the compound was composed, Experimental Example 6 became a wider band gap.

Further, in order to investigate the material structure having a large band gap, the band gap was estimated by using the molecular orbital calculation of the Gaussian 03 program for the compound of Experimental Example 1, the compound of Experimental Example 6, and DBTPB.

As a result, as shown in Table 1, the compound of Experimental Example 6 had a larger band gap than the compound of DBTPB and Experimental Example 1.

Further, for the films of Experimental Example 1, Experimental Example 6, and DBTPB, FluoroMax-4 manufactured by HORIBA Co., Ltd., and an excitation light source having a wavelength of 300 nm were used, and the luminescence spectrum was measured at a low temperature of 77K. Phosphorescence can be observed at low temperatures. Therefore, knowledge of the excitation triplet (T ₁ ) energy of each film can be obtained from the results of luminescence spectroscopy at low temperatures. Further, in order to remove the fluorescent luminescent component, the phosphorescence spectrum was observed, and after the excitation light was irradiated, a retardation of 200 msec was set, and the luminescence spectrum at a low temperature was measured. The results are shown in Figure 4.

Further, a film composed of Ir(mppy) ₃ represented by the above formula (162) of a green phosphor material was produced. Next, for the film composed of Ir(mppy) ₃ , FluoroMax-4 manufactured by HORIBA Co., Ltd. was used, and an excitation light source having a wavelength of 300 nm was used, and no luminescence was set at room temperature, and the luminescence spectrum of the entire time region was measured. The results are shown in Figure 4.

4 is a graph showing the results of measurement of the luminescence spectrum of the film of Experimental Example 1, the film of Experimental Example 6, and the DBTPB film at a low temperature, and the measurement results of the luminescence spectrum of the film composed of Ir(mppy) ₃ at room temperature.

As shown in FIG. 4, the phosphorescence spectral peak of Experimental Example 6 was on the shorter wavelength side than DBTPB, Experimental Example 1, and Ir(mppy) ₃ . That is, the excited triplet state (T ₁ ) energy of Experimental Example 6 was larger than that of DBTPB, Experimental Example 1, and Ir(mppy) ₃ . Further, as indicated by the arrow in Fig. 4, the phosphorescence spectral peak of DBTPB is the same as that of Ir(mppy) ₃ .

From the viewpoint of energy enclosed in view of hole transport layer material should be greater than the T ₁ energy T ₁ energy of the guest material. As is apparent from the results shown in Fig. 4, the hole transporting layer composed of the compounds of Experimental Example 1 and Experimental Example 6 can encapsulate the energy of the excited triplet state (T ₁ ) when Ir(mppy) ₃ is used as the guest material. Therefore, it is assumed that an organic EL device having high luminous efficiency can be obtained by using a light-emitting layer of Ir(mppy) ₃ for a hole transport layer composed of a compound of Experimental Example 1 and/or Experimental Example 6 and a guest material. .

"Organic EL device"

(Experimental Example 2)

a first electrode (anode) made of ITO (indium tin oxide) and a hole injection layer made of SHI2520-b10SI manufactured by Nissan Chemical Co., Ltd. and having a thickness of 30 nm are formed on the substrate by a conventional method; a second hole transporting layer composed of α-NPD represented by the formula (208) and having a thickness of 20 nm; a hole transporting layer composed of the compound represented by the above formula (1-83) and having a thickness of 10 nm; Ir(mppy) ₃ represented by the formula (162), a host material using Bepp2 represented by the above formula (132), and a light-emitting layer having a guest material content of 6 wt% and a thickness of 35 nm in the light-emitting layer 6; An electron transporting layer composed of TPBI having a thickness of 40 nm and having a thickness of 1 nm and a second electrode (cathode) composed of an Al film.

(Experimental Example 3)

The organic EL device of Experimental Example 3 was formed in the same manner as in Experimental Example 2 except that the material of the hole transport layer was changed to DBTPB represented by the above formula (5).

The relationship between the current density and the external quantum efficiency was investigated for the organic EL devices of Experimental Example 2 and Experimental Example 3. The results are shown in Figure 5.

As shown in Fig. 5, in Experimental Example 2 having a hole transporting layer composed of the compound represented by the above formula (1-83), the external quantum efficiency of Experimental Example 3 having a hole transporting layer composed of DBTPB was improved as a whole. This is conceivable because, in Experimental Example 2, compared with Experimental Example 3, the band gap energy of the hole transport layer and the excited triplet state (T ₁ ) energy were large.

Further, in the organic EL devices of Experimental Example 2 and Experimental Example 3, the driving life of the device was investigated as follows. That is, the current value was set to an initial luminance of 1000 cd/m ² , and the luminance attenuation at a constant current was observed. The result is shown in Fig. 6.

Fig. 6 is a graph showing the relationship between the driving time and the luminance of the organic EL elements of Experimental Example 2 and Experimental Example 3. The experimental example 2 shown in Fig. 6 was attenuated to 950 cd/m ² for 200 hours. On the other hand, the time during which Experimental Example 3 was attenuated to the same brightness was 84 hours. In this way, the compound of the present invention is not only highly efficient but also effective for long life.

(Experimental Example 4)

By using a conventional method, a first electrode (anode) composed of ITO (indium tin oxide), a hole injection layer composed of PEDOT:PSS represented by the general formula (131) and having a thickness of 35 nm is sequentially disposed on the substrate; a second hole transport layer composed of α-NPD represented by the general formula (208) and having a thickness of 20 nm; a hole transport layer composed of a compound represented by the above formula (1-107) and having a thickness of 10 nm; the guest material using the above formula (162) Ir (mppy) ₃ , the host material uses Bepp2 represented by the above formula (132), and the light-emitting layer 6 has a guest material content of 6 wt% and a thickness of 35 nm; (209) An electron transporting layer having a thickness of 40 nm and having a TPBI structure; an electron injecting layer made of a LiF film and having a thickness of 1 nm; and a second electrode (cathode) made of an Al film.

(Experimental Example 5)

The organic EL device of Experimental Example 5 was formed in the same manner as in Experimental Example 4 except that the material of the hole transport layer was replaced by DBTPB represented by the above formula (5).

The relationship between the current density and the external quantum efficiency was investigated for the organic EL devices of Experimental Example 4 and Experimental Example 5. The results are shown in Figure 7.

As shown in Fig. 7, Experimental Example 4 having a hole transporting layer composed of the compound represented by the above formula (1-107) was compared with Experimental Example 5 having a hole transporting layer composed of DBTPB, and the external quantum efficiency was overall. improve. This is conceivable because Experimental Example 4 is caused by the band gap energy of the hole transport layer and the energy of the excited triplet state (T ₁ ) as compared with the experimental example 5.

Further, with respect to the organic EL devices of Experimental Example 4 and Experimental Example 5, the driving life of the device was examined in the same manner as in Experimental Example 2 and Experimental Example 3. The result is shown in Fig. 8.

Fig. 8 is a graph showing the relationship between the driving time and the luminance of the organic EL device of Experimental Example 4 and Experimental Example 5. The time from the experimental example 4 shown in Fig. 8 to the attenuation to 800 cd/m ² was 108 hours. On the other hand, the time during which Experimental Example 5 was attenuated to the same brightness was 57 hours. In this way, the compound of the present invention is not only highly efficient but also effective for long life.

"Organic EL device"

(Experimental Example 7)

Forming on the substrate in sequence by a conventional method: a first electrode (anode) composed of ITO (indium tin oxide); a hole injection layer composed of PEDOT:PSS and having a thickness of 35 nm; as shown by the above formula (208) a second hole transport layer composed of α-NPD and having a thickness of 10 nm; a hole transport layer composed of a compound represented by the above formula (2-85) and having a thickness of 10 nm; and a guest material using Ir as shown in the above formula (162); Mppy) ₃ , the host material uses Bepp2 represented by the above formula (132), and the light-emitting layer 6 has a guest material content of 6 wt% and a thickness of 35 nm; the TPBI represented by the above formula (209) An electron transport layer having a thickness of 40 nm; an electron injection layer made of a LiF film and having a thickness of 1 nm; and a second electrode (cathode) made of an Al film.

(Experimental Example 8)

The organic EL element of Experimental Example 8 was formed in the same manner as in Experimental Example 7, except that the material of the hole transport layer was replaced by DBTPB represented by the above formula (5). Pieces.

The relationship between the current density and the external quantum efficiency was investigated for the organic EL devices of Experimental Example 7 and Experimental Example 8. The result is shown in Fig. 9.

As shown in Fig. 9, Experimental Example 7 having a hole transporting layer composed of the compound represented by the above formula (2-85) was compared with Experimental Example 8 having a hole transporting layer composed of DBTPB, and the external quantum efficiency was overall. improve. This is conceivable because Experimental Example 7 is caused by a larger band gap energy and an excited triplet state (T ₁ ) energy of the hole transport layer than in Experimental Example 8.

1‧‧‧Organic EL elements (organic electroluminescent elements)

2‧‧‧Substrate

3‧‧‧2nd electrode

4‧‧‧Electronic injection layer

5‧‧‧Electronic transport layer

6‧‧‧Lighting layer

7‧‧‧ hole transport layer

8‧‧‧ hole injection layer

9‧‧‧1st electrode

Claims (10)

a compound of the following formula (1-1), comprising a diaminobiphenyl group disposed between two dibenzothiophenes or between two dibenzofurans; In the general formula (1-1), two A are the same as oxygen or sulfur; Xa and Xb each independently represent hydrogen or any one of the following (a) to (c), and any of Xa and Xb When it is hydrogen, the other is hydrogen; Ya and Yb each independently represent (d); (a) is a linear or cyclic alkyl or alkoxy group which may have a substituent, and The substituent of (a) a linear or cyclic alkyl group or alkoxy group which may have a substituent is any one of an alkyl group, a halogen group, an amine group, a nitro group and a cyano group; (b), (d) Is an aromatic cyclic group which may have a substituent, and the substituent of the aromatic ring group which may have a substituent of (b) and (d) is a chain or a cyclic alkyl group, a halogen group, an amine group, Any one of a nitro group and a cyano group, the aromatic ring group of (b) and (d) is an aromatic hydrocarbon group or an aromatic heterocyclic group; (c) is a halogen group, an amine group, a nitro group and a cyano group. Any of them. A compound of the following formula (1-2), characterized in that it contains a diaminobiphenyl group disposed between two dibenzothiophenes or between two dibenzofurans, and is bonded to The bonding position of the amino group of the aforementioned diaminobiphenyl group is 4, 4'position; In the general formula (1-2), two A are the same as oxygen or sulfur; Xa and Xb each independently represent hydrogen or any one of the following (a) to (c), and any of Xa and Xb When it is hydrogen, the other is hydrogen; Ya and Yb each independently represent (d); (a) is a linear or cyclic alkyl or alkoxy group which may have a substituent, and The substituent of (a) a linear or cyclic alkyl group or alkoxy group which may have a substituent is any one of an alkyl group, a halogen group, an amine group, a nitro group and a cyano group; (b), (d) Is an aromatic cyclic group which may have a substituent, and the substituent of the aromatic ring group which may have a substituent of (b) and (d) is a chain or a cyclic alkyl group, a halogen group, an amine group, Any one of a nitro group and a cyano group, the aromatic ring group of (b) and (d) is an aromatic hydrocarbon group or an aromatic heterocyclic group; (c) is a halogen group, an amine group, a nitro group and a cyano group. Any of them. A compound according to claim 1 or 2, wherein either or both of Xa and Xb are methyl. The compound of any one of claims 1 to 3, wherein either or both of Ya and Yb are phenyl. The compound according to any one of claims 1 to 3, wherein either or both of Ya and Yb are 2,2'-dimethyl-1,1'-biphenyl. The compound according to any one of claims 1 to 5, wherein the substitution position of the two dibenzothiophenes or the substitution position of the two dibenzofurans is 4 positions. The compound according to any one of claims 1 to 5, wherein the substitution position of the two dibenzothiophenes or the substitution position of the two dibenzofurans is two. An organic electroluminescence device having a light-emitting layer between a cathode and an anode and a hole transport layer disposed on the anode side of the light-emitting layer, wherein the hole transport layer contains the request 1 to the request The compound of any one of item 7. The organic electroluminescence device according to claim 8, wherein the light-emitting layer comprises a host material and a guest material composed of the light-emitting material, and the guest material is an electron transporting material or a charge-transporting material of a hole and an electron. The organic electroluminescent device of claim 9, wherein the guest material is phosphorescent material.