JP2015019018A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-voltage organic EL element.SOLUTION: An organic EL element includes an anode, a light-emitting layer, an organic thin-film layer, and a cathode in this order. The light-emitting layer contains a compound represented by formula (1). The organic thin-film layer is in contact with the light-emitting layer and contains a compound represented by formula (2).

Description

  The present invention relates to an organic electroluminescence element.

Organic electroluminescence (EL) elements include a fluorescent type and a phosphorescent type, and suitable element designs are being studied according to the respective light emission mechanisms. With respect to phosphorescent organic EL elements, it is known from their light emission characteristics that high-performance elements cannot be obtained by simple diversion of fluorescent element technology. The reason is generally considered as follows.
Since phosphorescent light emission is light emission using triplet excitons, the energy gap of the compound used for the light emitting layer needs to be large. This is because the value of the energy gap of a compound (the energy difference between the lowest excited singlet state and the ground state) is usually the value of the triplet energy of the compound (the energy difference between the lowest excited triplet state and the ground state). It is because it is larger than.

  In a light-emitting layer including a host material and a phosphorescent material (hereinafter, the light-emitting material may be referred to as a guest), the phosphorescent material is allowed to emit light more efficiently than the triplet energy of the phosphorescent material. High triplet energy host materials must be used. For this reason, a host material having a high triplet energy level is required. In addition, in order to emit light efficiently, it is necessary to confine host and guest excitons in the light emitting layer.

  Reduction of the driving voltage of the organic EL element is an indispensable technique for improving the light emission efficiency, and improvements are being promoted. In order to reduce the voltage, it is necessary to use a material having excellent charge injection property or charge transport property.

For the above reasons, material selection and device design different from those of the fluorescent organic EL device are required for improving the performance of the phosphorescent organic EL device.
Regarding the above, Patent Document 1 discloses an organic EL element using a polycyclic compound having a heteroacene skeleton as a host material for phosphorescence. Patent Document 2 exemplifies a benzimidazole compound having an azacarbazolyl group and uses it as a phosphorescent host material and an electron transport layer material.
Patent Document 3 exemplifies a benzimidazole compound having an azacarbazole skeleton, and uses the benzimidazole compound as an electron transport layer material. Patent Document 4 exemplifies a compound having an azacarbazole skeleton and uses it as a host material for a phosphorescent dopant.

WO2009-148015 pamphlet JP 2009-158848 A JP 2010-118591 A JP 2011-84531 A

  An object of the present invention is to provide a low voltage organic electroluminescence device.

（式（１）中、
Ｘ_１及びＸ_２は、それぞれ独立に酸素原子、硫黄原子、又はＲを有する窒素原子（−ＮＲ−）である。
Ｒ_１、Ｒ_２及びＲは、それぞれ独立に、水素原子、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
Ｒ_３及びＲ_４は、それぞれ独立に、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基又はシアノ基である。
ｓ及びｔはそれぞれ独立に０又は１である。
Ａｒ_１及びＡｒ_２は、それぞれ独立に、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換のカルバゾリル基、置換もしくは無置換のアリールカルバゾリル基、置換もしくは無置換のアザカルバゾリル基、置換もしくは無置換のアリールアザカルバゾリル基、置換もしくは無置換のジベンゾフラニル基、置換もしくは無置換のアリールジベンゾフラニル基、置換もしくは無置換のアザジベンゾフラニル基、置換もしくは無置換のアリールアザジベンゾフラニル基、置換もしくは無置換のジベンゾチオフェニル基、置換もしくは無置換のアリールジベンゾチオフェニル基、置換もしくは無置換のアザジベンゾチオフェニル基、又は置換もしくは無置換のアリールアザジベンゾチオフェニル基である。
但し、Ｒ_３とＡｒ_１は同一ではなく、Ｒ_４とＡｒ_２は同一ではない。Ｒ_１〜Ｒ_４、Ｒ、Ｘ_１、Ｘ_２、Ａｒ_１及びＡｒ_２のうちいずれか２つで環を形成してもよい。）

（式（２）中、
Ｘ_３は、酸素原子、硫黄原子、又はＲ’を有する窒素原子（−ＮＲ’−）である。
Ｙ_１〜Ｙ_８は、それぞれ独立に、ＣＨ又は窒素原子である。但し、Ｙ_１〜Ｙ_８のうち少なくとも１つは窒素原子であり、Ｙ_１〜Ｙ_４のいずれか１つは、Ｒ_７の結合手と結合する炭素原子であり、Ｙ_５〜Ｙ_８のいずれか１つは、カルバゾール環の窒素原子の結合手と結合する炭素原子である。
Ｒ’は、水素原子、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
Ｒ_５〜Ｒ_７は、それぞれ独立に、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
ｐ、ｑ、及びｒは、それぞれ０又は１である。） According to the present invention, the following organic EL elements are provided.
An organic electroluminescence device including an anode, a light emitting layer, an organic thin film layer, and a cathode in this order,
The light emitting layer contains a compound represented by the following formula (1):
An organic electroluminescence device comprising a compound represented by the following formula (2), wherein the organic thin film layer is in contact with a light emitting layer.

(In the formula (1),
X ₁ and X ₂ are each independently an oxygen atom, a sulfur atom, or a nitrogen atom (—NR—) having R.
R ₁ , R ₂ and R are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, substituted or unsubstituted Substituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, substituted or unsubstituted An unsubstituted ring-forming heteroaromatic ring group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group is there.
R ₃ and R ₄ each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
s and t are each independently 0 or 1.
Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted arylcarbazolyl group, Substituted or unsubstituted azacarbazolyl group, substituted or unsubstituted arylazacarbazolyl group, substituted or unsubstituted dibenzofuranyl group, substituted or unsubstituted aryldibenzofuranyl group, substituted or unsubstituted azadibenzofuranyl group Group, substituted or unsubstituted arylazadibenzofuranyl group, substituted or unsubstituted dibenzothiophenyl group, substituted or unsubstituted aryldibenzothiophenyl group, substituted or unsubstituted azadibenzothiophenyl group, or substituted or unsubstituted A substituted arylazadibenzothiophenyl group;
However, R ₃ and Ar ₁ are not the same, and R ₄ and Ar ₂ are not the same. Any one of R _{1 to} R ₄ , R, X ₁ , X ₂ , Ar ₁ and Ar ₂ may form a ring. )

(In the formula (2),
X ₃ is an oxygen atom, a sulfur atom, or a nitrogen atom (—NR′—) having R ′.
Y _{1 to} Y ₈ are each independently CH or a nitrogen atom. However, at least one of Y _{1 to} Y ₈ is a nitrogen atom, and any one of Y _{1 to} Y ₄ is a carbon atom bonded to the bond of R ₇ , and any of Y _{5 to} Y ₈ One is a carbon atom bonded to the bond of the nitrogen atom of the carbazole ring.
R ′ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. A substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted ring atom number of 5 to 5 18 heteroaromatic ring groups, substituted or unsubstituted silyl groups, fluorine atoms, substituted or unsubstituted fluoroalkyl groups, substituted or unsubstituted fluoroalkoxy groups, or cyano groups.
R _{5 to} R ₇ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
p, q, and r are each 0 or 1. )

  ADVANTAGE OF THE INVENTION According to this invention, a low voltage organic electroluminescent element can be provided.

The organic EL device according to one embodiment of the present invention is an organic electroluminescence device including an anode, a light emitting layer, an organic thin film layer, and a cathode in this order, and the light emitting layer contains a compound represented by the following formula (1), The organic thin film layer is in contact with the light emitting layer and contains a compound represented by the following formula (2).
Hereinafter, these compounds will be described.

[Compound represented by Formula (1)]
The compound represented by the formula (1) is a polycyclic compound having a heteroacene skeleton. Since the compound represented by the formula (1) is a compound having a non-linear heteroacene skeleton instead of an acene skeleton typified by pentacene, it has excellent durability and high triplet energy. In a preferred embodiment, Ar ₁ and Ar ₂ containing an aromatic heterocyclic group such as a carbazolyl group are bonded to both ends of the heteroacene skeleton, and these groups can contribute to high triplet energy.
When the compound represented by the formula (1) is used as a host material in combination with a light emitting material in a light emitting layer, energy transfer to the light emitting material is facilitated and can contribute to an improvement in light emission efficiency. The compound represented by the formula (1) can be suitably used as a host material of a phosphorescent light-emitting material, and in particular, high luminous efficiency may be obtained even when used as a host material of a blue phosphorescent light-emitting material.

（式（１）中、
Ｘ_１及びＸ_２は、それぞれ独立に酸素原子、硫黄原子、又はＲを有する窒素原子（−ＮＲ−）である。
Ｒ_１、Ｒ_２及びＲは、それぞれ独立に、水素原子、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
Ｒ_３及びＲ_４は、それぞれ独立に置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基又はシアノ基である。
ｓ及びｔは、それぞれ独立に０又は１である。
Ａｒ_１及びＡｒ_２は、それぞれ独立に、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換のカルバゾリル基、置換もしくは無置換のアリールカルバゾリル基、置換もしくは無置換のアザカルバゾリル基、置換もしくは無置換のアリールアザカルバゾリル基、置換もしくは無置換のジベンゾフラニル基、置換もしくは無置換のアリールジベンゾフラニル基、置換もしくは無置換のアザジベンゾフラニル基、置換もしくは無置換のアリールアザジベンゾフラニル基、置換もしくは無置換のジベンゾチオフェニル基、置換もしくは無置換のアリールジベンゾチオフェニル基、置換もしくは無置換のアザジベンゾチオフェニル基、又は置換もしくは無置換のアリールアザジベンゾチオフェニル基である。
Ｒ_３とＡｒ_１は同一ではなく、Ｒ_４とＡｒ_２は同一ではない。Ｒ_１〜Ｒ_４、Ｒ、Ｘ_１、Ｘ_２、Ａｒ_１及びＡｒ_２のうちいずれか２つは環を形成してもよい。） The compound represented by formula (1) is preferably used as a host material. In this case, a structure that can transport both electrons and holes is preferable.
In the compound represented by the formula (1), main structures that affect carrier (electron or hole) transport are atoms represented by X ₁ and X ₂ , and suitable Ar ₁ and Ar ₂ described later. These are preferably compounds having both a structure contributing to the expression of electron transport properties and a structure contributing to the expression of hole transport properties. This is because higher light emission efficiency can be expected compared to the case where the structure contributes to the expression of electron transport properties or the case where the structure contributes to the expression of hole transport properties. Specific examples of such compounds include compounds used in Examples, H1 to H5.

(In the formula (1),
X ₁ and X ₂ are each independently an oxygen atom, a sulfur atom, or a nitrogen atom (—NR—) having R.
R ₁ , R ₂ and R are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, substituted or unsubstituted Substituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, substituted or unsubstituted An unsubstituted ring-forming heteroaromatic ring group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group is there.
R ₃ and R ₄ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number 1 to 20 alkoxy groups, substituted or unsubstituted cycloalkoxy groups having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon ring groups having 6 to 18 ring carbon atoms, substituted or unsubstituted ring atoms A heteroaromatic cyclic group of 5 to 18; a substituted or unsubstituted silyl group; a fluorine atom; a substituted or unsubstituted fluoroalkyl group; a substituted or unsubstituted fluoroalkoxy group; or a cyano group.
s and t are each independently 0 or 1.
Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted arylcarbazolyl group, Substituted or unsubstituted azacarbazolyl group, substituted or unsubstituted arylazacarbazolyl group, substituted or unsubstituted dibenzofuranyl group, substituted or unsubstituted aryldibenzofuranyl group, substituted or unsubstituted azadibenzofuranyl group Group, substituted or unsubstituted arylazadibenzofuranyl group, substituted or unsubstituted dibenzothiophenyl group, substituted or unsubstituted aryldibenzothiophenyl group, substituted or unsubstituted azadibenzothiophenyl group, or substituted or unsubstituted A substituted arylazadibenzothiophenyl group;
R ₃ and Ar ₁ are not the same, and R ₄ and Ar ₂ are not the same. Any _two of R _{1 to} R ₄ , R, X ₁ , X ₂ , Ar ₁ and Ar ₂ may form a ring. )

（式（４）中、Ｘ_１、Ｘ_２、Ｒ_１〜Ｒ_４、Ａｒ_１、Ａｒ_２、ｓ及びｔは、前記式（１）と同様である。）

（式（８）中、Ｘ_１、Ｘ_２、Ｒ_３、Ｒ_４、Ａｒ_１、Ａｒ_２、ｓ及びｔは、前記式（１）と同様である。） The compound represented by the formula (1) is preferably a compound represented by the following formula (4), and more preferably a compound represented by the following formula (8).

(In the formula (4), X ₁ , X ₂ , R _{1 to} R ₄ , Ar ₁ , Ar ₂ , s, and t are the same as those in the formula (1).)

(In the formula (8), X ₁ , X ₂ , R ₃ , R ₄ , Ar ₁ , Ar ₂ , s, and t are the same as those in the formula (1).)

The compound of formula (4) specifies the bonding position of Ar ₁ and Ar ₂ . A high triplet energy can be obtained by setting the bonding position of Ar ₁ and Ar _{2 to} the position of Formula (4), which is considered to have a positive effect on the improvement of the light emission efficiency and the extension of the lifetime.
In the compound of the formula (8), R ₁ and R ₂ are limited to hydrogen atoms. By using R ₁ and R ₂ as a hydrogen atom, it is considered that the triplet energy and long life are positively affected.
The triplet energy can be measured by a known method. For example, the sample is dissolved in EPA solvent (diethyl ether: isopentane: ethanol = 5: 5: 2 (volume ratio)) at 10 μmol / L to obtain a sample for phosphorescence measurement. This phosphorescence measurement sample is put in a quartz cell, irradiated with excitation light at a temperature of 77 K, and the phosphorescence spectrum of the emitted phosphorescence is measured. This can be defined as a value obtained by the conversion formula E ^T (eV) = 1239.85 / λ _edge . “Λ _edge ” is a phosphorescence spectrum with the vertical axis representing the phosphorescence intensity and the horizontal axis representing the wavelength, and a tangent line is drawn with respect to the short wavelength side rise of the phosphorescence spectrum, and the intersection of the tangent line and the horizontal axis. Means a wavelength value (unit: nm).

In the formulas (1), (4), and (8), X ₁ and X ₂ are preferably each independently an oxygen atom or a sulfur atom in that they may contribute to the long life of the organic EL device. is there.

R ₁ and R ₂ are preferably each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 carbon atoms. And more preferably a hydrogen atom.
R ₃ and R ₄ are preferably each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, More preferably, it is a C6-C12 aromatic hydrocarbon cyclic group.
s and t are preferably each independently 0.
R is preferably a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms.

Ar ₁ and Ar ₂ are preferably each independently substituted or unsubstituted carbazolyl group, substituted or unsubstituted arylcarbazolyl group, substituted or unsubstituted azacarbazolyl group, substituted or unsubstituted arylazacarbazolyl Group, substituted or unsubstituted dibenzofuranyl group, substituted or unsubstituted aryl dibenzofuranyl group, substituted or unsubstituted azadibenzofuranyl group, substituted or unsubstituted arylazadibenzofuranyl group, substituted or unsubstituted A dibenzothiophenyl group, a substituted or unsubstituted aryl dibenzothiophenyl group, a substituted or unsubstituted azadibenzothiophenyl group, or a substituted or unsubstituted arylazadibenzothiophenyl group, and more preferably a substituted or unsubstituted group. Substituted carbazolyl group, Or unsubstituted azacarbazolyl group, or a substituted or unsubstituted dibenzofuranyl group.
These groups are preferred because they contribute to the high triplet energy of the compound of formula (1).

In the present specification, an azacarbazolyl group, an azadibenzofuranyl group and an azadibenzothiophenyl group are, for example, an azacarbazolyl group, an azadibenzofuranyl group and an azadibenzothiophenyl group each containing 1 to 5 nitrogen atoms.
The bond of the substituent may be present on any nitrogen atom or any carbon atom, and any nitrogen atom or any carbon atom may be substituted.

Ar ₁ and Ar ₂ substituted or unsubstituted arylcarbazolyl group, substituted or unsubstituted arylazacarbazolyl group, substituted or unsubstituted aryldibenzofuranyl group, substituted or unsubstituted arylazadibenzofuranyl In the group, substituted or unsubstituted aryldibenzothiophenyl group, substituted or unsubstituted arylazadibenzothiophenyl group, “aryl” is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 18 carbon atoms forming a ring. Groups, and preferred aryls include phenyl and biphenyl.

Regarding the bond of Ar ₁ and Ar _2, the bond between the bond and Ar ₁ and Ar ₂ is not necessarily an aryl moiety, and the bond may be bonded to other than the aryl moiety of Ar ₁ and Ar _2. .

In Formula (1), the bond of R _{3 and} the bond of Ar ₁ are benzene rings adjacent to a 5-membered ring containing X ₁ , and R ₁ and R ₂ are not substituted ( Bonded to the carbon atom of the following benzene ring 1). Similarly, the bond of R _{4 and} the bond of Ar ₂ are benzene rings adjacent to the 5-membered ring containing X ₂ , and R ₁ and R ₂ are not substituted (the following benzene ring 2). To each carbon atom.
Note that when s is 0, a bond of _{R 3} and _{R 3} is absent, when t is 0, a bond of _{R 4} and and _{R 4} are absent.

  The compound represented by the formula (1), the formula (4) or the formula (8) can be produced, for example, by the method described in WO2009-148015.

Specific examples of the compound represented by the formula (1) are shown below. In addition, the compound represented by Formula (1) is not limited to the following specific example.

（式（２）中、
Ｘ_３は、酸素原子、硫黄原子、又はＲ’を有する窒素原子（−ＮＲ’−）である。
Ｙ_１〜Ｙ_８は、それぞれ独立に、ＣＨ又は窒素原子である。但し、Ｙ_１〜Ｙ_８のうち少なくとも１つは窒素原子であり、Ｙ_１〜Ｙ_４のいずれか１つは、Ｒ_７の結合手と結合する炭素原子であり、Ｙ_５〜Ｙ_８のいずれか１つは、カルバゾール環の窒素原子の結合手と結合する炭素原子である。
Ｒ’は、水素原子、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
Ｒ_５〜Ｒ_７は、それぞれ独立に、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
ｐ、ｑ、及びｒは、それぞれ０又は１である。） [Compound represented by formula (2)]
The compound represented by the formula (2) includes a carbazole ring and an azalated three-ring hetero ring (a central ring is a 5-membered ring containing a hetero atom) as shown below, and the nitrogen atom of the carbazole ring Have a structure bonded to the six-membered ring constituting the three-ring heterocycle. This structure can contribute to the expression of high triplet energy and electron transport properties. For this reason, it is thought that it has a positive influence on the improvement of luminous efficiency and voltage reduction.
The compound represented by the formula (2) having such a structure is an organic thin film layer disposed between the light emitting layer and the cathode constituting the organic EL element, and is contained in a layer adjacent to the light emitting layer It is. Specifically, it is used as an electron transport material. Furthermore, it is considered that it has a function of confining the excitons of the host and guest in the light emitting layer, which is considered to contribute to the improvement of the light emission efficiency.

(In the formula (2),
X ₃ is an oxygen atom, a sulfur atom, or a nitrogen atom (—NR′—) having R ′.
Y _{1 to} Y ₈ are each independently CH or a nitrogen atom. However, at least one of Y _{1 to} Y ₈ is a nitrogen atom, and any one of Y _{1 to} Y ₄ is a carbon atom bonded to the bond of R ₇ , and any of Y _{5 to} Y ₈ One is a carbon atom bonded to the bond of the nitrogen atom of the carbazole ring.
R ′ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. A substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted ring atom number of 5 to 5 18 heteroaromatic ring groups, substituted or unsubstituted silyl groups, fluorine atoms, substituted or unsubstituted fluoroalkyl groups, substituted or unsubstituted fluoroalkoxy groups, or cyano groups.
R _{5 to} R ₇ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
p, q, and r are each 0 or 1. )

（式（５）中、
Ｘ_３〜Ｘ_５は、それぞれ独立に、酸素原子、硫黄原子、又はＲ’を有する窒素原子である。
Ｙ_１〜Ｙ_８は、それぞれ独立に、ＣＨ又は窒素原子である。但し、Ｙ_１〜Ｙ_８のうち少なくとも１つは窒素原子であり、Ｙ_１〜Ｙ_４のいずれか１つは、Ｒ_７の結合手と結合する炭素原子であり、Ｙ_５〜Ｙ_８のいずれか１つは、カルバゾール環の窒素原子の結合手と結合する炭素原子である。
Ｒ’は、それぞれ独立に、水素原子、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
Ｒ_７〜Ｒ_９は、それぞれ独立に、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
ｑ、ｒ、ｘ及びｙは、それぞれ独立に０又は１である。）

（式（７）中、
Ｘ_６〜Ｘ_８は、それぞれ独立に、酸素原子、又は硫黄原子である。
Ｙ_１〜Ｙ_６及びＹ_８は、それぞれ独立に、ＣＨ又は窒素原子である。但し、Ｙ_１〜Ｙ_６、Ｙ_８のうち少なくとも１つは窒素原子であり、Ｙ_１〜Ｙ_４のいずれか１つは、Ｒ_７の結合手と結合する炭素原子である。
Ｒ_７〜Ｒ_９は、それぞれ独立に、置換もしくは無置換の炭素数１〜２０のアルキル基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルキル基、置換もしくは無置換の炭素数１〜２０のアルコキシ基、置換もしくは無置換の環形成炭素数３〜２０のシクロアルコキシ基、置換もしくは無置換の環形成炭素数６〜１８の芳香族炭化水素環基、置換もしくは無置換の環形成原子数５〜１８のヘテロ芳香族環基、置換もしくは無置換のシリル基、フッ素原子、置換もしくは無置換のフルオロアルキル基、置換もしくは無置換のフルオロアルコキシ基、又はシアノ基である。
ｒ、ｘ及びｙは、それぞれ０又は１である。） The compound represented by the formula (2) is preferably a compound represented by the following formula (5), more preferably a compound represented by the following formula (7).
The compound represented by the formula (5) is a carbazolyl group in which R ₅ and R ₆ of the compound represented by the formula (2) are substituted with R ₈ or R ₉ , a dibenzofuranyl group substituted with R ₈ or R ₉ , And a compound limited to a group selected from a dibenzothiophenyl group substituted with R ₈ or R ₉ .
Similarly, the compound represented by formula (7) is a compound in which q of the compound represented by formula (5) is limited to 1, and X _{3 to} X ₅ are each limited to an oxygen atom or a sulfur atom.

(In Formula (5),
X _{3 to} X ₅ are each independently an oxygen atom, a sulfur atom, or a nitrogen atom having R ′.
Y _{1 to} Y ₈ are each independently CH or a nitrogen atom. However, at least one of Y _{1 to} Y ₈ is a nitrogen atom, and any one of Y _{1 to} Y ₄ is a carbon atom bonded to the bond of R ₇ , and any of Y _{5 to} Y ₈ One is a carbon atom bonded to the bond of the nitrogen atom of the carbazole ring.
R ′ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
R _{7 to} R ₉ each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
q, r, x, and y are each independently 0 or 1. )

(In formula (7),
X < ₆ > -X < ₈ > is an oxygen atom or a sulfur atom each independently.
Y _{1 to} Y ₆ and Y ₈ are each independently CH or a nitrogen atom. However, at least one of Y _{1 to} Y ₆ and Y ₈ is a nitrogen atom, and any one of Y _{1 to} Y ₄ is a carbon atom bonded to the bond of R ₇ .
R _{7 to} R ₉ each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
r, x, and y are 0 or 1, respectively. )

In the formulas (2) and (5), X _{3 to} X ₅ are each preferably an oxygen atom or a sulfur atom independently from the viewpoint that they may contribute to the long life of the organic EL element.

In formulas (2), (5), and (7), among Y _{1 to} Y ₄ , for example, any three may be nitrogen atoms, but preferably any two are nitrogen atoms, and more preferably Any one is a nitrogen atom. Similarly, among Y ₅ to Y ₈ , for example, any three may be nitrogen atoms, but preferably any two are nitrogen atoms, more preferably any one is a nitrogen atom, particularly preferably. Are not nitrogen atoms.
Any one of Y _{1 to} Y ₄ is a carbon atom bonded to the bond of R ₇ , but when R ₇ is a hydrogen atom, all of Y _{1 to} Y ₄ may be CH. .

In Formula (2), R ₅ and R ₆ are preferably each independently a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms.
In formula (2), one of p and q is 0, one of R ₅ or R ₆ is absent, and the other is a substituted or unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms. Also preferred in some cases

The heteroaromatic cyclic group having 5 to 18 ring atoms is preferably a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, or a substituted or unsubstituted dibenzothiophenyl group.
The substituted or unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms is preferably an unsubstituted heteroaromatic cyclic group having 5 to 18 ring atoms. Examples of the group include an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms, and a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms. Is preferred. Examples of the substituent in a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms and a substituted or unsubstituted heteroaromatic ring group having 5 to 18 ring atoms include 5 ring-forming atoms. Examples include a phenyl group substituted with a -18 heteroaromatic ring group and a heteroaromatic ring group having 5 to 18 ring atoms.

In the formulas (2), (5) and (7), R ₇ is preferably an alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms. .
In the formulas (2), (5) and (7), R ′ is preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms, and more preferably a phenyl group.

In the formulas (5) and (7), R ₈ and R ₉ are preferably an alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 ring carbon atoms.

In the formulas (2), (5) and (7), p, q, r, x and y are each independently 0 or 1, preferably 0.
For example, when p is 0, R ₆ and the bond in the parentheses of p are lost. The same applies to q, r, x and y.

In the formula (2), when p = q = 1, the bond of R _{5 and} the bond of R ₆ are bonded to different benzene rings of the carbazole ring, and the same benzene ring of the carbazole ring In addition, neither the bond of R ₅ nor the bond of R ₆ is bonded.
Similarly, in formulas (5) and (7), when x = y = 1, each bond of R ₈ and R ₉ and two bonds of the carbazole ring are different from each other in the same heterofluorene ring. Bonded to each benzene ring.
For example, in the heterofluorene ring containing X ₄ in formula (5), the bond of R _{9 and} the bond of the carbazole ring are respectively bonded to different benzene rings of the heterofluorene ring containing X ₄ . In the heterofluorene ring containing X ₅ in formula (5), the bond of R _{8 and} the bond of the carbazole ring are bonded to different benzene rings of the heterofluorene ring containing X ₅ , respectively.

The compounds represented by formula (2), formula (5) and formula (7) can be produced, for example, using the method disclosed in WO2012 / 090967 and WO2010 / 122810. The compounds represented by formula (2), formula (5) and formula (7) can be produced, for example, as follows:
2-Bromo-3-hydroxypyridine and 2-fluorophenylboronic acid are reacted in the presence of potassium carbonate, N, N-dimethylacetamide and Pd (PPh ₃ ) ₄ to produce 1-azadibenzofuran.
The resulting 1-azadibenzofuran is reacted with 1,4-dibromobutane in THF in the presence of nBuLi to produce 6-bromo-1-azadibenzofuran. Also, 1-azadibenzofuran is reacted with bromine in nitrobenzene to produce 8-bromo-1-azadibenzofuran.
On the other hand, dibenzofuran-2-boronic acid and 3,6-dibromocarbazole were reacted in the presence of an aqueous sodium carbonate solution, dimethoxyethane, and Pd (PPh ₃ ) ₄ to obtain a compound in which dibenzofuran was bonded to the 3,6-positions of carbazole. To manufacture.
The produced 3,6-dibenzofuranylcarbazole and 6-bromo-1-azadibenzofuran or 8-bromo-1-azadibenzofuran were mixed with K ₃ PO ₄ , CuI, trans-1,2-diaminocyclohexane and 1,4. -By reacting in the presence of dioxane, the compounds ET7 and ET8 of Examples can be produced.

Specific examples of the compound represented by the formula (2) are shown below. In addition, the compound represented by Formula (2) is not limited to the following specific example.

Hereinafter, each substituent etc. of the compound represented by Formula (1) and Formula (2) are demonstrated.
In this specification, the aromatic hydrocarbon ring includes a monocyclic aromatic hydrocarbon ring group and a condensed aromatic hydrocarbon ring group in which a plurality of hydrocarbon rings are condensed, and the heteroaromatic ring is a monocyclic heterocycle. An aromatic ring group, a hetero-fused aromatic ring group in which a plurality of heteroaromatic rings are condensed, and a hetero-fused aromatic ring group in which an aromatic hydrocarbon ring and a heteroaromatic ring are condensed are included.
In the present specification, the hydrogen atom includes isotopes having different numbers of neutrons, that is, light hydrogen (protium), deuterium (triuterium), and tritium.
The “ring-forming carbon” means a carbon atom constituting a saturated ring, an unsaturated ring, or an aromatic ring. “Ring-forming atom” means an atom constituting a saturated ring, an unsaturated ring, or an aromatic ring.

  Specific examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n- Heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n- Examples include heptadecyl group, n-octadecyl group, neopentyl group, 1-methylpentyl group, 2-methylpentyl group, 1-pentylhexyl group, 1-butylpentyl group, 1-heptyloctyl group, 3-methylpentyl group and the like. Of these, those having 1 to 6 carbon atoms are preferred.

  Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a norbornyl group, an adamantyl group, etc. Among them, those having 5 or 6 ring carbon atoms are preferable.

  Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, and a hexyloxy group. Those having 3 or more carbon atoms may be linear, cyclic or branched, Of these, those having 1 to 6 carbon atoms are preferred.

  Examples of the cycloalkoxy group include a cyclopentoxy group and a cyclohexyloxy group, and among them, those having 5 or 6 ring carbon atoms are preferable.

  Specific examples of the aromatic hydrocarbon ring group (aryl group) include phenyl group, tolyl group, xylyl group, mesityl group, o-biphenyl group, m-biphenyl group, p-biphenyl group, o-terphenyl group, m -Terphenyl group, p-terphenyl group, naphthyl group, phenanthryl group, triphenylene group and the like can be mentioned. Of these, a phenyl group, m-biphenyl group, and m-terphenyl group are preferred. Those having 6 to 18 ring carbon atoms are preferred.

  Specific examples of the aromatic heterocyclic group (heteroaromatic ring group) (heteroaryl group) include pyrrolyl group, pyrazinyl group, pyridinyl group, pyrimidinyl group, pyridazinyl group, triazinyl group, indolyl group, isoindolyl group, furyl group, Benzofuranyl group, isobenzofuranyl group, dibenzofuranyl group, dibenzothiophenyl group, quinolyl group, isoquinolyl group, quinoxalinyl group, carbazolyl group, azacarbazolyl group, phenanthridinyl group, acridinyl group, phenanthrolinyl group, thienyl Group, pyrrolidinyl, dioxanyl, piperidinyl, morpholinyl, piperazinyl, carbazolyl, thiophenyl, oxazolyl, oxadiazolyl, benzoxazolyl, thiazolyl, thiadiazolyl, benzothiazolyl, Examples include azolyl group, imidazolyl group, benzimidazolyl group, pyranyl group, benzo [c] dibenzofuranyl group, azadibenzofuranyl group, azadibenzothiophenyl group, azacarbazolyl group, etc. Those are preferred.

  Examples of the fluoroalkyl group include a group in which one or more fluorine atoms are substituted on the above-described alkyl group, specifically, a trifluoromethyl group, a pentafluoroethyl group, a 2,2,2-trifluoroethyl group. Etc. are preferred.

  Examples of the fluoroalkoxy group include groups in which one or more fluorine atoms are substituted on the above-described alkoxy group, and specifically include a trifluoromethoxy group, a pentafluoroethoxy group, and a 2,2,2-trifluoroethoxy group. Etc. are preferred.

  Examples of the substituted or unsubstituted silyl group include a trialkylsilyl group in which three alkyl groups having 1 to 6 carbon atoms such as a trimethylsilyl group and a triethylsilyl group are bonded to a silicon atom, and a ring-forming carbon such as a triphenyl group. Examples thereof include a triarylsilyl group in which 3 to 18 aromatic hydrocarbon groups are bonded to a silicon atom.

  Examples of the substituent that may be substituted for each of the above groups include a halogen atom such as a fluorine atom, an alkyl group having 1 to 10 carbon atoms (specific groups are the same as those described above), and a ring-forming carbon number of 3 to 20 Cycloalkyl groups (specific groups are the same as above), alkoxy groups having 1 to 6 carbon atoms (specific groups are the same as above), cycloalkoxy groups having 3 to 10 ring carbon atoms (specific groups) Is the same as above), an aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms (specific groups are the same as above), a heteroaromatic ring group having 5 to 18 ring atoms (specific groups are The same as above, a silyl group (specific groups are the same as above), and a cyano group.

[Organic EL device]
Next, the structure of the organic EL element according to one embodiment of the present invention will be described.
The organic EL device of the present invention according to one embodiment of the present invention is an organic electroluminescence device in which an anode, a light emitting layer, an organic thin film layer, and a cathode are laminated in this order, and the light emitting layer is represented by the formula (1). The organic thin film layer in contact with the light emitting layer contains a compound represented by the formula (2).
If the organic EL element which concerns on one form of this invention is an element which has the said structure, another structure will not be limited. That is, another organic thin film layer or intermediate electrode layer may be disposed between the anode and the cathode.

A light emitting layer may contain 1 type of compounds represented by Formula (1) individually, or 2 or more types.
The light emitting layer preferably contains a light emitting material (dopant) other than the compound represented by the formula (1) in addition to the compound represented by the formula (1).
The light emitting material is preferably a phosphorescent light emitting material (phosphorescent dopant). The concentration of the light emitting material in the light emitting layer is preferably 0.1 to 40% by mass, more preferably 0.1 to 30% by mass.

Examples of the phosphorescent dopant include metal complex compounds and the like, preferably a compound having a metal atom selected from Ir, Pt, Os, Au, Cu, Re and Ru and a ligand. The ligand preferably has an ortho metal bond.
The phosphorescent dopant is preferably a compound containing a metal atom selected from Ir, Os and Pt, more preferably a metal complex such as an iridium complex, an osmium complex, or a platinum complex, and more preferably an iridium complex and a platinum complex. Orthometalated iridium complexes are most preferred. The dopant may be a single type or a mixture of two or more types.

  The organic thin film layer adjacent to the light emitting layer and disposed on the cathode side may contain one or more of the compounds represented by formula (2). Furthermore, a known electron transport material may be included.

In addition to the above-described embodiment, the organic EL element according to one embodiment of the present invention can employ various known configurations.
In the organic EL device of the present invention, the configuration other than the layer using the organic EL device material according to one embodiment of the present invention is not particularly limited, and a known material or the like can be used. Hereinafter, although the layer of an organic EL element is demonstrated easily, the material applied to the organic EL element which concerns on one form of this invention is not limited to the following.

  Hereinafter, the substrate / anode / hole injection layer / hole transport layer / light emitting layer / organic thin film layer (first electron transport layer) / second electron transport layer / electron injection layer / cathode are laminated in this order. Each layer will be described using an organic EL element as an example.

(substrate)
The substrate is used as a support for the light emitting element. As the substrate, for example, glass, quartz, plastic, or the like can be used. Further, a flexible substrate may be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates such as polycarbonate, polyarylate, polyethersulfone, polypropylene, polyester, polyvinyl fluoride, and polyvinyl chloride. . A film on which an inorganic material is deposited can also be used. In an embodiment in which light emission is extracted from the substrate, a highly transparent material is preferable.

(anode)
For the anode formed on the substrate, it is preferable to use a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a high work function (specifically, 4.0 eV or more). Specifically, for example, indium oxide-tin oxide (ITO: Indium Tin Oxide), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, tungsten oxide, and indium oxide containing zinc oxide. And graphene. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium ( Pd), titanium (Ti), or a metal material nitride (for example, titanium nitride).

  The anode is usually formed by sputtering using the above materials. For example, indium oxide-zinc oxide is a target in which 1 to 10 wt% of zinc oxide is added to indium oxide, tungsten oxide, and indium oxide containing zinc oxide is 0.5 to 0.5 in tungsten oxide relative to indium oxide. By using a target containing 5 wt% and zinc oxide 0.1 to 1 wt%, it can be formed by a sputtering method. In addition, you may produce by the vacuum evaporation method, the apply | coating method, the inkjet method, a spin coat method, etc.

(Hole injection layer)
The hole injection layer is a layer containing a substance having a high hole injection property. Substances with high hole injection properties include molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, Tungsten oxide, manganese oxide, or the like can be used.
As a material for the hole injection layer, 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″, which is a low molecular organic compound. -Tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4'-bis [N- (4-diphenylaminophenyl) -N-phenylamino] biphenyl ( Abbreviation: DPAB), 4,4′-bis (N- {4- [N ′-(3-methylphenyl) -N′-phenylamino] phenyl} -N-phenylamino) biphenyl (abbreviation: DNTPD), 1 , 3,5-tris [N- (4-diphenylaminophenyl) -N-phenylamino] benzene (abbreviation: DPA3B), 3- [N- (9-phenylcarbazol-3-yl) -N-phenylamino ] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 3- [ An aromatic amine compound such as N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1) and the like can also be given.

  As a material for the hole injection layer, a polymer compound (oligomer, dendrimer, polymer, or the like) can also be used. For example, poly (N-vinylcarbazole) (abbreviation: PVK), poly (4-vinyltriphenylamine) (abbreviation: PVTPA), poly [N- (4- {N ′-[4- (4-diphenylamino)] Phenyl] phenyl-N′-phenylamino} phenyl) methacrylamide] (abbreviation: PTPDMA), poly [N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine] (abbreviation: Polymer compounds such as Poly-TPD). In addition, a polymer compound to which an acid such as poly (3,4-ethylenedioxythiophene) / poly (styrenesulfonic acid) (PEDOT / PSS), polyaniline / poly (styrenesulfonic acid) (PAni / PSS) is added is used. You can also.

(Hole transport layer)
The hole transport layer is a layer containing a substance having a high hole transport property.
An aromatic amine compound, a carbazole derivative, an anthracene derivative, or the like can be used for the hole transport layer. Specifically, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB) or N, N′-bis (3-methylphenyl) -N, N′— Diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4-phenyl-4 ′-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: BAFLP), 4 , 4′-bis [N- (9,9-dimethylfluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: DFLDPBi), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) ) Triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4′-bis [N- (Spiro-9,9'-Biff Oren-2-yl) -N- phenylamino] biphenyl (abbreviation: BSPB), it is possible to use an aromatic amine compounds such HTM1, such HTM2 used in Examples. The substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or higher.

For the hole transport layer, a carbazole derivative such as CBP, CzPA, or PCzPA, or an anthracene derivative such as t-BuDNA, DNA, or DPAnth may be used. A high molecular compound such as poly (N-vinylcarbazole) (abbreviation: PVK) or poly (4-vinyltriphenylamine) (abbreviation: PVTPA) can also be used.
Any other substance may be used as long as it has a property of transporting more holes than electrons. Note that the layer containing a substance having a high hole-transport property is not limited to a single layer, and two or more layers containing the above substances may be stacked.

(Light emitting layer)
The light-emitting layer is a layer including a substance having high light-emitting properties, and various materials can be used. For example, as the substance having high light-emitting property, a fluorescent compound that emits fluorescence or a phosphorescent compound that emits phosphorescence can be used. A fluorescent compound is a compound that can emit light from a singlet excited state, and a phosphorescent compound is a compound that can emit light from a triplet excited state.
As the phosphorescent compound, an orthometalated complex of a metal atom selected from iridium (Ir), osmium (Os), platinum (Pt), and gold (Au) is preferable in terms of light emission efficiency.

  As a blue fluorescent material that can be used for the light emitting layer, pyrene derivatives, styrylamine derivatives, chrysene derivatives, fluoranthene derivatives, fluorene derivatives, diamine derivatives, triarylamine derivatives, and the like can be used. Specifically, N, N′-bis [4- (9H-carbazol-9-yl) phenyl] -N, N′-diphenylstilbene-4,4′-diamine (abbreviation: YGA2S), 4- (9H -Carbazol-9-yl) -4 '-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), 4- (10-phenyl-9-anthryl) -4'-(9-phenyl-9H -Carbazol-3-yl) triphenylamine (abbreviation: PCBAPA) and the like.

  An aromatic amine derivative or the like can be used as a green fluorescent material that can be used for the light emitting layer. Specifically, N- (9,10-diphenyl-2-anthryl) -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N- [9,10-bis (1,1 '-Biphenyl-2-yl) -2-anthryl] -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N- (9,10-diphenyl-2-anthryl) -N, N ', N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N- [9,10-bis (1,1'-biphenyl-2-yl) -2-anthryl] -N, N' , N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), N- [9,10-bis (1,1′-biphenyl-2-yl)]-N- [4- (9H-carbazole) -9-Ile Phenyl] -N- phenyl-anthracene-2-amine (abbreviation: 2YGABPhA), N, N, 9- triphenylamine anthracene-9-amine (abbreviation: DPhAPhA), and the like.

Tetracene derivatives, diamine derivatives, and the like can be used as red fluorescent materials that can be used for the light emitting layer. Specifically, N, N, N ′, N′-tetrakis (4-methylphenyl) tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N, N, N ′, And N′-tetrakis (4-methylphenyl) acenaphtho [1,2-a] fluoranthene-3,10-diamine (abbreviation: p-mPhAFD).
As a blue phosphorescent material that can be used for the light emitting layer, a metal complex such as an iridium complex, an osmium complex, or a platinum complex is used. Specifically, bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C2 ′] iridium (III) tetrakis (1-pyrazolyl) borate (abbreviation: FIr6), bis [2- (4 ′ , 6′-difluorophenyl) pyridinato-N, C2 ′] iridium (III) picolinate (abbreviation: FIrpic), bis [2- (3 ′, 5′bistrifluoromethylphenyl) pyridinato-N, C2 ′] iridium (III ) Picolinate (abbreviation: Ir (CF3ppy) 2 (pic)), bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C2 ′] iridium (III) acetylacetonate (abbreviation: FIracac) and implementation Examples include the iridium complex used in the examples.

  An iridium complex or the like is used as a green phosphorescent material that can be used for the light emitting layer. Tris (2-phenylpyridinato-N, C2 ′) iridium (III) (abbreviation: Ir (ppy) 3), bis (2-phenylpyridinato-N, C2 ′) iridium (III) acetylacetonate ( Abbreviations: Ir (ppy) 2 (acac)), bis (1,2-diphenyl-1H-benzimidazolato) iridium (III) acetylacetonate (abbreviation: Ir (pbi) 2 (acac)), bis (benzo [ h] quinolinato) iridium (III) acetylacetonate (abbreviation: Ir (bzq) 2 (acac)) and the like.

As a red phosphorescent material that can be used for the light emitting layer, a metal complex such as an iridium complex, a platinum complex, a terbium complex, or a europium complex is used. Specifically, bis [2- (2′-benzo [4,5-α] thienyl) pyridinato-N, C3 ′] iridium (III) acetylacetonate (abbreviation: Ir (btp) 2 (acac)), Bis (1-phenylisoquinolinato-N, C2 ′) iridium (III) acetylacetonate (abbreviation: Ir (piq) 2 (acac)), (acetylacetonato) bis [2,3-bis (4-fluoro Phenyl) quinoxalinato] iridium (III) (abbreviation: Ir (Fdpq) 2 (acac)), 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin platinum (II) (abbreviation) : PtOEP) and the like.
Tris (acetylacetonato) (monophenanthroline) terbium (III) (abbreviation: Tb (acac) 3 (Phen)), Tris (1,3-diphenyl-1,3-propanedionate) (monophenanthroline) europium (III) (abbreviation: Eu (DBM) 3 (Phen)), tris [1- (2-thenoyl) -3,3,3-trifluoroacetonato] (monophenanthroline) europium (III) (abbreviation: Eu ( A rare earth metal complex such as TTA) 3 (Phen)) emits light from a rare earth metal ion (electron transition between different multiplicity), and thus can be used as a phosphorescent compound.

(Host material for light emitting layer)
The light-emitting layer of the organic EL element according to one embodiment of the present invention preferably has a structure in which the above-described light-emitting material) is dispersed in another substance (host material).

As the host material, compounds of formula (1), formula (4), and formula (8) are preferable, but the following substances can be used in combination as long as the effects of the present invention are not impaired.
Substances (host materials) for dispersing the light-emitting material include 1) metal complexes such as aluminum complexes, beryllium complexes, or zinc complexes, 2) heterocyclic compounds such as oxadiazole derivatives, benzimidazole derivatives, or phenanthroline derivatives 3) condensed aromatic compounds such as carbazole derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives or chrysene derivatives, 3) aromatic amine compounds such as triarylamine derivatives or condensed polycyclic aromatic amine derivatives are used. .

  Specific examples of the host material include tris (8-quinolinolato) aluminum (III) (abbreviation: Alq), tris (4-methyl-8-quinolinolato) aluminum (III) (abbreviation: Almq3), and bis (10-hydroxy). Benzo [h] quinolinato) beryllium (II) (abbreviation: BeBq2), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (III) (abbreviation: BAlq), bis (8-quinolinolato) zinc (II) (abbreviation: Znq), bis [2- (2-benzoxazolyl) phenolato] zinc (II) (abbreviation: ZnPBO), bis [2- (2-benzothiazolyl) phenolato] zinc (II) (abbreviation) : ZnBTZ) and the like, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1, , 4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7) ), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), 2,2 ′, 2 ″-(1, Heterocyclic compounds such as 3,5-benzenetriyl) tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), and 9- [4 -(10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9- [4- (10-phenyl-9-anthryl) phenyl]- H-carbazole (abbreviation: DPCzPA), 9,10-bis (3,5-diphenylphenyl) anthracene (abbreviation: DPPA), 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert- Butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 9,9′-bianthryl (abbreviation: BANT), 9,9 ′-(stilbene-3,3′-diyl) diphenanthrene (Abbreviation: DPNS), 9,9 ′-(stilbene-4,4′-diyl) diphenanthrene (abbreviation: DPNS2), 3,3 ′, 3 ″-(benzene-1,3,5-triyl) tripyrene (Abbreviation: TPB3), 9,10-diphenylanthracene (abbreviation: DPAnth), 6,12-dimethoxy-5,11-diphenylchrysene, etc. Compound, N, N-diphenyl-9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: CzA1PA), 4- (10-phenyl-9-anthryl) Triphenylamine (abbreviation: DPhPA), N, 9-diphenyl-N- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: PCAPA), N, 9-diphenyl -N- {4- [4- (10-phenyl-9-anthryl) phenyl] phenyl} -9H-carbazol-3-amine (abbreviation: PCAPBA), N- (9,10-diphenyl-2-anthryl)- N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), NPB (or α-NPD), TPD, DFLDPBi, BSPB And the like can be used aromatic amine compound. In addition, a plurality of substances (host materials) for dispersing a substance having high luminescence (guest material) can be used.

(Organic thin film layer (first electron transport layer))
The organic thin film layer provided on the cathode side adjacent to the light emitting layer includes an electron transport property and a compound having a high triplet energy level, thereby transporting electrons to the light emitting layer and excitons formed in the light emitting layer. This is a layer for preventing the diffusion of light, increasing the exciton concentration in the light emitting layer, and improving the light emission efficiency.
Compounds represented by formula (2), formula (5), and formula (7) can be used.
This organic thin film layer is disposed as a first electron transport layer in an organic EL device having two or more electron transport layers. Since the first electron transport layer has a high triplet energy level, it may be difficult to inject electrons from the cathode or an electron injection layer described later. In such a case, it is preferable to dispose a second electron transport layer including a known electron transport material.

(Electron transport layer (second electron transport layer))
The electron transport layer is a layer containing a substance having a high electron transport property.
In the electron transport layer, compounds of the formula (2), formula (5), and formula (7) can be used. Besides, 1) metal complexes such as aluminum complexes, beryllium complexes, zinc complexes, etc., 2) imidazole derivatives, Heteroaromatic compounds such as benzimidazole derivatives, azine derivatives, carbazole derivatives, and phenanthroline derivatives, and 3) polymer compounds can be used.
Specific examples of the material for the electron transport layer include low molecular organic compounds such as Alq, tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq3), bis (10-hydroxybenzo [h] quinolinato) beryllium. (Abbreviation: BeBq2), metal complexes such as BAlq, Znq, ZnPBO, and ZnBTZ can be used. In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (Pert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- (4- Biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4- Triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 4,4′-bis (5-methylbenzoxazol-2-yl) stilbene (abbreviation: B) zOs) and heteroaromatic compounds such as ETM1 used in the examples can also be used.
The substances mentioned here are mainly substances having an electron mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that a substance other than the above substance may be used for the electron transport layer as long as the substance has a higher electron transport property than the hole transport property. Further, the electron-transporting layer is not limited to a single layer, and two or more layers including the above substances may be stacked.
Moreover, a high molecular compound can also be used for an electron carrying layer. For example, poly [(9,9-dihexylfluorene-2,7-diyl) -co- (pyridine-3,5-diyl)] (abbreviation: PF-Py), poly [(9,9-dioctylfluorene-2) , 7-diyl) -co- (2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) or the like can be used.

(Electron injection layer)
The electron injection layer is a layer containing a substance having a high electron injection property.
For the electron injection layer, lithium (Li), cesium (Cs), calcium (Ca), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), lithium oxide (LiOx), etc. Such alkali metals, alkaline earth metals, or compounds thereof can be used. In addition, a substance containing an electron transporting property containing an alkali metal, an alkaline earth metal, or a compound thereof, specifically, a substance containing magnesium (Mg) in Alq may be used. In this case, electron injection from the cathode can be performed more efficiently.

A composite material obtained by mixing an organic compound and an electron donor (electron donating dopant) may be used for the electron injection layer. Such a composite material is excellent in electron injecting property and electron transporting property because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material excellent in transporting the generated electrons. Specifically, for example, a substance (metal complex, heteroaromatic compound, or the like) constituting the electron transport layer described above is used. be able to.
The electron donor may be any substance that exhibits an electron donating property to the organic compound. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferable, and lithium, cesium, magnesium, calcium, erbium, ytterbium, and the like can be given. Alkali metal oxides and alkaline earth metal oxides are preferable, and lithium oxide, calcium oxide, barium oxide, and the like can be given. A Lewis base such as magnesium oxide can also be used. Alternatively, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can be used.

(cathode)
For the cathode, it is preferable to use a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a small work function (specifically, 3.8 eV or less). Specific examples of such a cathode material include elements belonging to Group 1 or Group 2 of the periodic table of elements, that is, alkali metals such as lithium (Li) and cesium (Cs), and magnesium (Mg) and calcium (Ca ), Alkaline earth metals such as strontium (Sr), and alloys containing these (for example, rare earth metals such as MgAg, AlLi), europium (Eu), ytterbium (Yb), and alloys containing these.
In addition, when forming a cathode using an alkali metal, an alkaline earth metal, and an alloy containing these, a vacuum evaporation method or a sputtering method can be used. Moreover, when using a silver paste etc., the apply | coating method, the inkjet method, etc. can be used.
When light emission is extracted from the cathode side, the cathode needs to be thinned. In this case, for example, the above-described transparent substrate may be disposed outside the cathode.

  When the electron injection layer is provided, the cathode can be formed using various conductive materials such as indium oxide-tin oxide containing Al, Ag, ITO, graphene, silicon, or silicon oxide regardless of the work function. it can. These conductive materials can be formed by a sputtering method, an inkjet method, a spin coating method, or the like.

Next, the present invention will be described in more detail using examples. However, the present invention is not limited to the following examples.
The material used for manufacture of the organic EL element of an Example and a comparative example is shown below.

１，３−ジフルオロ−２−ブロモベンゼン７０ｇ（３６３ｍｍｏｌ）、塩化鉄１１．８ｇ（７２．６ｍｍｏｌ）をクロロホルム３５０ｍｌに加え、０℃で撹拌した。次いで、臭素６２．７ｇ（３９９ｍｍｏｌ）を滴下し、４時間撹拌した。反応溶液に水１Ｌを加えて有機相を分取した後、有機相を水酸化ナトリウム水溶液で洗浄し、溶媒を減圧下で留去した。得られた残渣をヘプタンに溶解し、シリカゲルカラムクロマトグラフィー（展開溶媒：ヘプタンのみ）で精製することにより、目的物である中間体（１−１）を８９．１ｇ（収率９０％）得た。 Synthesis example 1
For the above compound, for example, Compound H2 was prepared by the following method.
(1) Synthesis of intermediate (1-1)

70 g (363 mmol) of 1,3-difluoro-2-bromobenzene and 11.8 g (72.6 mmol) of iron chloride were added to 350 ml of chloroform and stirred at 0 ° C. Next, 62.7 g (399 mmol) of bromine was added dropwise and stirred for 4 hours. After adding 1 L of water to the reaction solution to separate the organic phase, the organic phase was washed with an aqueous sodium hydroxide solution, and the solvent was distilled off under reduced pressure. The obtained residue was dissolved in heptane and purified by silica gel column chromatography (developing solvent: heptane only) to obtain 89.1 g (yield 90%) of the intermediate (1-1) as the target product. .

アルゴン雰囲気下、中間体（１−１）８９．１ｇ（３２８ｍｍｏｌ）、２−メトキシフェニルボロン酸１０９．６ｇ（７２１ｍｍｏｌ）、Ｐｄ（ＰＰｈ_３）_４１５．２ｇ（１３．１ｍｍｏｌ）、２ＭＮａ_２ＣＯ_３水溶液９９０ｍｌを１，２−ジメトキシエタン（ＤＭＥ）１．３Ｌに加えて、アルゴン雰囲気下、加熱還流条件で３６時間撹拌した。室温に戻したのち、酢酸エチル１Ｌを加えて有機相を分取した後、溶媒を減圧下で留去した。得られた残渣をトルエンに溶解し、シリカゲルカラムクロマトグラフィー（展開溶媒：トルエン）で精製することにより、目的物である中間体（１−２）を９８．８ｇ（収率９２％）得た。 (2) Synthesis of intermediate (1-2)

Under an argon atmosphere, 89.1 g (328 mmol) of the intermediate (1-1), 109.6 g (721 mmol) of 2-methoxyphenylboronic acid, 15.2 g (13.1 mmol) of Pd (PPh ₃ ) ₄ , 2MNa ₂ CO ₃ 990 ml of an aqueous solution was added to 1.3 L of 1,2-dimethoxyethane (DME), and the mixture was stirred for 36 hours under heating and reflux conditions in an argon atmosphere. After returning to room temperature, 1 L of ethyl acetate was added to separate the organic phase, and then the solvent was distilled off under reduced pressure. The obtained residue was dissolved in toluene, and purified by silica gel column chromatography (developing solvent: toluene) to obtain 98.8 g (yield 92%) of the target intermediate (1-2).

中間体（１−２）９８．８ｇ（３０３ｍｍｏｌ）をＮ，Ｎ−ジメチルホルムアミド（ＤＭＦ）５００ｍｌに加えた溶液に、ＤＭＦ３００ｍｌに溶解したＮ−ブロモコハク酸イミド（ＮＢＳ）１１３．２ｇ（６３６ｍｍｏｌ）を１時間かけて滴下した。室温で１時間撹拌した後、亜硫酸ナトリウム水溶液を反応液に加え、析出した固体を濾集した。この固体をメタノール、水で順次洗浄し、加熱したトルエンに溶解させた。この溶液を保温しながらシリカゲルカラムクロマトグラフィー（展開溶媒：トルエン）で精製し、さらにヘプタンで懸濁洗浄することにより、目的物である中間体（１−３）を１３６．２ｇ（収率９２％）得た。 (3) Synthesis of intermediate (1-3)

To a solution obtained by adding 98.8 g (303 mmol) of intermediate (1-2) to 500 ml of N, N-dimethylformamide (DMF), 13.2 g (636 mmol) of N-bromosuccinimide (NBS) dissolved in 300 ml of DMF was added. It was added dropwise over time. After stirring at room temperature for 1 hour, an aqueous sodium sulfite solution was added to the reaction solution, and the precipitated solid was collected by filtration. This solid was washed successively with methanol and water, and dissolved in heated toluene. The solution was purified by silica gel column chromatography (developing solvent: toluene) while keeping the temperature, and suspended and washed with heptane to obtain 136.2 g of the target intermediate (1-3) (yield 92%). )Obtained.

アルゴン雰囲気下、中間体（１−４）７０．３ｇ（１４５ｍｍｏｌ）をジクロロメタン４００ｍｌに加えた反応溶液を０℃で撹拌した。次いで、三臭化ホウ素８０．０ｇ（３１９ｍｍｏｌ）のジクロロメタン溶液を滴下し、室温に戻してから、１８時間撹拌した。再び、０℃に冷却してから、水３００ｍｌを加え、有機相を分取した。溶媒を減圧下で留去し、得られた残渣をシリカゲルカラムクロマトグラフィー（展開溶媒：トルエン）で精製することにより、目的物である中間体（１−４）を６６．０ｇ（収率９９％）得た。 (4) Synthesis of intermediate (1-4)

Under an argon atmosphere, a reaction solution obtained by adding 70.3 g (145 mmol) of intermediate (1-4) to 400 ml of dichloromethane was stirred at 0 ° C. Subsequently, a dichloromethane solution of 80.0 g (319 mmol) of boron tribromide was dropped, and the mixture was returned to room temperature and stirred for 18 hours. After cooling again to 0 ° C., 300 ml of water was added to separate the organic phase. The solvent was distilled off under reduced pressure, and the resulting residue was purified by silica gel column chromatography (developing solvent: toluene) to obtain 66.0 g of the target intermediate (1-4) (99% yield). )Obtained.

アルゴン雰囲気下、中間体（１−４）１０．０ｇ（２１．９ｍｍｏｌ）、炭酸カリウム１２．０ｇ（８７．７ｍｍｏｌ）をＮ−メチルピロリドン（ＮＭＰ）１００ｍｌに加え、１８０℃で１５時間撹拌した。室温に戻して、水１００ｍｌを加え、析出した固体を濾集した。固体をキシレンに加熱溶解し、シリカゲル１０ｇを加えてから、濾過した。濾液を濃縮し、析出した固体をキシレン溶媒で再結晶を繰り返して精製することにより、目的物である中間体（１−５）を４．１ｇ（収率４５％）得た。 (5) Synthesis of intermediate (1-5)

Under an argon atmosphere, 10.0 g (21.9 mmol) of intermediate (1-4) and 12.0 g (87.7 mmol) of potassium carbonate were added to 100 ml of N-methylpyrrolidone (NMP), and the mixture was stirred at 180 ° C. for 15 hours. The temperature was returned to room temperature, 100 ml of water was added, and the precipitated solid was collected by filtration. The solid was dissolved by heating in xylene, and 10 g of silica gel was added, followed by filtration. The filtrate was concentrated, and the precipitated solid was purified by repeated recrystallization with a xylene solvent to obtain 4.1 g (yield 45%) of the desired intermediate (1-5).

アルゴン雰囲気下、中間体（１−５）２．５ｇ（６．０１ｍｍｏｌ）、カルバゾール２．５ｇ（１５．０ｍｍｏｌ）Ｐｄ_２（ｄｂａ）_３０．２２ｇ（０．２４ｍｍｏｌ）、ｔ−Ｂｕ_３Ｐ−ＨＢＦ_４０．２８ｇ（０．９６ｍｍｏｌ）、ｔ−ブトキシナトリウム１．６ｇ（１６．６ｍｍｏｌ）をキシレン５０ｍｌに加え、１５０℃で２４時間撹拌した。トルエン８００ｍｌを加え、加熱溶解させたものを、シリカゲルカラムクロマトグラフィー（展開溶媒：トルエン）で精製した。溶媒を減圧下で留去して析出した固体をアセトンで洗浄を繰り返すことにより、化合物Ｈ２を３．０ｇ（収率８４％）の白色固体として得た。
得られた化合物Ｈ２についてＦＤ−ＭＳ分析した結果、分子量５８８に対してｍ／ｅ＝５８８であった。 (6) Synthesis of compound H2

Under an argon atmosphere, intermediate (1-5) 2.5 g (6.01 mmol), carbazole 2.5 g (15.0 mmol) Pd ₂ (dba) ₃ 0.22 g (0.24 mmol), t-Bu ₃ P— HBF ₄ 0.28 g (0.96 mmol) and t-butoxy sodium 1.6 g (16.6 mmol) were added to xylene 50 ml, and the mixture was stirred at 150 ° C. for 24 hours. A solution obtained by adding 800 ml of toluene and dissolving by heating was purified by silica gel column chromatography (developing solvent: toluene). The solvent was distilled off under reduced pressure, and the precipitated solid was repeatedly washed with acetone to obtain 3.0 g (yield 84%) of white solid as compound H2.
As a result of FD-MS analysis of the obtained compound H2, the molecular weight was 588, and m / e = 588.

Example 1
[Manufacture of organic EL elements]
A 25 mm × 75 mm × 1.1 mm glass substrate with an ITO transparent electrode (manufactured by Geomatic) was subjected to ultrasonic cleaning for 5 minutes in isopropyl alcohol, and further subjected to UV (Ultraviolet) ozone cleaning for 30 minutes. .
The glass substrate with the transparent electrode thus cleaned is attached to the substrate holder of the vacuum evaporation apparatus, and first, on the surface of the glass substrate on which the transparent electrode line is formed, the transparent electrode is covered, HTM1 was deposited with a thickness of 20 nm to form a hole injection layer. Subsequently, HTM2 was vapor-deposited with a thickness of 60 nm on this film to form a hole transport layer.
On the hole transport layer, H1 as a phosphorescent host material and D1 as a phosphorescent material were co-evaporated with a thickness of 40 nm to form a phosphorescent layer. The concentration of H1 in the phosphorescent light emitting layer was 80% by mass, and the concentration of D1 was 20% by mass.
Subsequently, ET6 was vapor-deposited with a thickness of 5 nm on the phosphorescent light-emitting layer to form a first electron transport layer, and further, ETM1 was vapor-deposited with a thickness of 25 nm to form a second electron transport layer. A cathode was formed by sequentially laminating 1 nm of LiF and 80 nm of metal Al. In addition, about LiF which is an electron injectable electrode, it vapor-deposited at the speed | rate of 1 liter / min.

[Light-emitting performance evaluation of organic EL elements]
A voltage was applied to the produced organic EL element so that the current density was 1 mA / cm ^2, and the voltage value at that time was measured. Further, the EL emission spectrum at that time was measured with a spectral radiance meter (CS-1000: manufactured by Konica Minolta). External quantum efficiency (%) and main peak wavelength λp (nm) were calculated from the obtained spectral radiance spectrum.
Moreover, about the produced organic EL element, the element lifetime (LT70: time for a brightness | luminance to fall to 70%) in initial stage brightness | luminance 3,000 cd / m < ² > was calculated | required.
The evaluation results of these light emitting performances are shown in Table 1.

Example 2
Except that the phosphorescent light emitting layer was formed using the compound H2 instead of the compound H1 as the phosphorescent host material, and the first electron transporting layer was formed using the compound ET8 instead of the compound ET6 as the electron transporting layer material. In the same manner as in Example 1, an organic EL device was produced and evaluated. The results are shown in Table 1.

Example 3
Example 1 except that the phosphorescent light emitting layer is formed using the compound H2 instead of the compound H1 as the phosphorescent host material, and the first electron transporting layer is formed using the compound ET7 instead of the compound ET6 as the electron transporting layer material. In the same manner as in Example 1, an organic EL device was produced and evaluated. The results are shown in Table 1.

Example 4
Except that the phosphorescent light emitting layer was formed using the compound H3 instead of the compound H1 as the phosphorescent host material, and the first electron transporting layer was formed using the compound ET7 instead of the compound ET6 as the electron transporting layer material. In the same manner as in Example 1, an organic EL device was produced and evaluated. The results are shown in Table 1.

Example 5
Except that the phosphorescent light emitting layer was formed using the compound H3 instead of the compound H1 as the phosphorescent host material, and the first electron transporting layer was formed using the compound ET8 instead of the compound ET6 as the electron transporting layer material. In the same manner as in Example 1, an organic EL device was produced and evaluated. The results are shown in Table 1.

Example 6
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that the phosphorescent light emitting layer was formed using the compound H4 instead of the compound H1 as the phosphorescent host material. The results are shown in Table 1.

Example 7
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that the phosphorescent light emitting layer was formed using Compound H5 instead of Compound H1 as the phosphorescent host material. The results are shown in Table 1.

Comparative Example 1
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that Compound A was used instead of ET6 as the material for the first electron transport layer. The results are shown in Table 1.

Comparative Example 2
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that Compound B was used instead of ET6 as the material for the first electron transport layer. The results are shown in Table 1.

Comparative Example 3
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that Compound H1 was used instead of ET6 as the material for the first electron transport layer. The results are shown in Table 1.

Comparative Example 4
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that the compound ETM1 was used instead of ET6 as the material for the first electron transport layer. The results are shown in Table 1.

Comparative Example 5
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that Compound C was used instead of H1 as the phosphorescent host material. The results are shown in Table 1.

The organic EL element of Examples 1-6 is excellent in a voltage and external quantum efficiency compared with the organic EL element of Comparative Examples 1-5. The device lifetime is also comparable to Comparative Examples 3 and 5, which showed excellent values. Thus, it turns out that Examples 1-6 which are one embodiment of this invention are excellent in element performance. The organic EL element of Example 7 is superior in terms of voltage as compared with the organic EL elements of Comparative Examples 1 to 5.

Claims (12)

An organic electroluminescence device including an anode, a light emitting layer, an organic thin film layer, and a cathode in this order,
The light emitting layer contains a compound represented by the following formula (1):
An organic electroluminescence device comprising a compound represented by the following formula (2), wherein the organic thin film layer is in contact with a light emitting layer.

(In the formula (1),
X ₁ and X ₂ are each independently an oxygen atom, a sulfur atom, or a nitrogen atom (—NR—) having R.
R ₁ , R ₂ and R are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, substituted or unsubstituted Substituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, substituted or unsubstituted An unsubstituted ring-forming heteroaromatic ring group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group is there.
R ₃ and R ₄ each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
s and t are each independently 0 or 1.
Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted arylcarbazolyl group, Substituted or unsubstituted azacarbazolyl group, substituted or unsubstituted arylazacarbazolyl group, substituted or unsubstituted dibenzofuranyl group, substituted or unsubstituted aryldibenzofuranyl group, substituted or unsubstituted azadibenzofuranyl group Group, substituted or unsubstituted arylazadibenzofuranyl group, substituted or unsubstituted dibenzothiophenyl group, substituted or unsubstituted aryldibenzothiophenyl group, substituted or unsubstituted azadibenzothiophenyl group, or substituted or unsubstituted A substituted arylazadibenzothiophenyl group;
However, R ₃ and Ar ₁ are not the same, and R ₄ and Ar ₂ are not the same. Any one of R _{1 to} R ₄ , R, X ₁ , X ₂ , Ar ₁ and Ar ₂ may form a ring. )

(In the formula (2),
X ₃ is an oxygen atom, a sulfur atom, or a nitrogen atom (—NR′—) having R ′.
Y _{1 to} Y ₈ are each independently CH or a nitrogen atom. However, at least one of Y _{1 to} Y ₈ is a nitrogen atom, and any one of Y _{1 to} Y ₄ is a carbon atom bonded to the bond of R ₇ , and any of Y _{5 to} Y ₈ One is a carbon atom bonded to the bond of the nitrogen atom of the carbazole ring.
R ′ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms. A substituted or unsubstituted cycloalkoxy group having 3 to 20 ring carbon atoms, a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms, a substituted or unsubstituted ring atom number of 5 to 5 18 heteroaromatic ring groups, substituted or unsubstituted silyl groups, fluorine atoms, substituted or unsubstituted fluoroalkyl groups, substituted or unsubstituted fluoroalkoxy groups, or cyano groups.
R _{5 to} R ₇ are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
p, q, and r are each 0 or 1. ) The organic electroluminescence device according to claim 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (4).

(In the formula (4), X ₁ , X ₂ , R _{1 to} R ₄ , Ar ₁ , Ar ₂ , s, and t are the same as those in the formula (1).) The organic electroluminescence device according to claim 1 or 2, wherein X ₁ and X _{2 in the} formula (1) or the formula (4) are each independently an oxygen atom or a sulfur atom. The organic electroluminescence device according to any one of claims 1 to 3, wherein the compound represented by the formula (1) is a compound represented by the following formula (8).

(In the formula (8), X ₁ , X ₂ , R ₃ , R ₄ , Ar ₁ , Ar ₂ , s, and t are the same as those in the formula (1).) Ar ₁ and Ar ₂ in the formula (1) are each independently a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted arylcarbazolyl group, a substituted or unsubstituted azacarbazolyl group, a substituted or unsubstituted group Arylazacarbazolyl group, substituted or unsubstituted dibenzofuranyl group, substituted or unsubstituted aryldibenzofuranyl group, substituted or unsubstituted azadibenzofuranyl group, substituted or unsubstituted arylazadibenzofuranyl group A substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted aryldibenzothiophenyl group, a substituted or unsubstituted azadibenzothiophenyl group, or a substituted or unsubstituted arylazadibenzothiophenyl group To 4. The organic electroluminescence according to any one of Nsu element. The organic electroluminescence device according to any one of claims 1 to 5, wherein the compound represented by the formula (2) is a compound represented by the following formula (5).

(In Formula (5),
X _{3 to} X ₅ are each independently an oxygen atom, a sulfur atom, or a nitrogen atom (—NR′—) having R ′.
Y _{1 to} Y ₈ are each independently CH or a nitrogen atom. However, at least one of Y _{1 to} Y ₈ is a nitrogen atom, and any one of Y _{1 to} Y ₄ is a carbon atom bonded to the bond of R ₇ , and any of Y _{5 to} Y ₈ One is a carbon atom bonded to the bond of the nitrogen atom of the carbazole ring.
R ′ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
R _{7 to} R ₉ each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
q, r, x, and y are each independently 0 or 1. ) X < ₃ > -X < ₅ > of said Formula (2) or said Formula (5) is an oxygen atom or a sulfur atom each independently, The organic electroluminescent element in any one of Claims 1-6. The organic electroluminescence device according to any one of claims 1 to 7, wherein the compound represented by the formula (2) is a compound represented by the following formula (7).

(In formula (7),
X < ₆ > -X < ₈ > is an oxygen atom or a sulfur atom each independently.
Y _{1 to} Y ₆ and Y ₈ are each independently CH or a nitrogen atom. However, at least one of Y _{1 to} Y ₆ and Y ₈ is a nitrogen atom, and any one of Y _{1 to} Y ₄ is a carbon atom bonded to the bond of R ₇ .
R _{7 to} R ₉ each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted carbon number of 1; ˜20 alkoxy group, substituted or unsubstituted ring-forming C3-C20 cycloalkoxy group, substituted or unsubstituted ring-forming C6-C18 aromatic hydrocarbon ring group, substituted or unsubstituted ring formation A heteroaromatic cyclic group having 5 to 18 atoms, a substituted or unsubstituted silyl group, a fluorine atom, a substituted or unsubstituted fluoroalkyl group, a substituted or unsubstituted fluoroalkoxy group, or a cyano group.
r, x, and y are 0 or 1, respectively. ) The light emitting layer includes a phosphorescent material;
The phosphorescent material is an orthometalated complex of one or more metal atoms selected from iridium (Ir), osmium (Os), platinum (Pt), and gold (Au). The organic electroluminescent element of description.   The organic electroluminescence device according to claim 1, wherein at least one maximum value of the emission wavelength from the light emitting layer is 500 nm or less.   The organic electroluminescent element in any one of Claims 1-10 with which the electron carrying layer was arrange | positioned between the said organic thin film layer and a cathode. The organic electroluminescent element according to any one of claims 1 to 11, wherein an organic layer containing an electron donating dopant is disposed in an interface region with the cathode.