JP2019176093A - Organic electroluminescence element - Google Patents

Abstract

To provide an element having excellent electron injection properties and excellent luminous efficiency in an organic electroluminescent element having a forward structure in which a cathode is formed on a substrate.SOLUTION: The organic electroluminescent element has a structure in which a plurality of layers including a light emitting layer 5 are laminated between a cathode 8 and an anode 2 formed on a substrate 1. Of the plurality of laminated layers, a layer 7 adjacent to the cathode 8 is an organic electroluminescence device containing a first material which is an organic material having an acid dissociation constant pKa of 1 or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to an organic electroluminescent device. More specifically, the present invention relates to an organic electroluminescent element that can be used as a display device such as a display unit of an electronic device, a lighting device, or the like.

Organic electroluminescent devices are thin, flexible and flexible. In addition, a display device using an organic electroluminescent element can display with high brightness and high definition as compared with a liquid crystal display device and a plasma display device which are currently mainstream. In addition, a display device using an organic electroluminescent element has a wider viewing angle than a liquid crystal display device. For this reason, display devices using organic electroluminescent elements are expected to expand in the future as displays for televisions and mobile phones. In addition, the organic electroluminescence element is expected to be used as a lighting device.

An organic electroluminescent element is formed by laminating a cathode, a light emitting layer, and an anode. In the organic electroluminescent device, the difference between the work function of the anode and the highest occupied orbital (HOMO) energy of the light emitting layer is smaller than the difference between the work function of the cathode and the lowest unoccupied orbital (LUMO) energy of the light emitting layer. Therefore, it is difficult to inject electrons from the cathode into the light emitting layer as compared to injecting holes from the anode. For this reason, in the conventional organic electroluminescent element, an electron injection layer is disposed between the cathode and the light emitting layer to promote injection of electrons from the cathode to the light emitting layer. In addition, efforts have been made to improve electron injection / transport properties by doping a dopant disposed between the cathode and the light emitting layer (see, for example, Non-Patent Document 1 and Non-Patent Document 2). .

As an electron injection layer of an organic electroluminescent element, an inorganic oxide layer is mentioned (for example, refer nonpatent literature 3). However, the inorganic oxide layer has insufficient electron injection properties.
In addition, there is a technique for improving the electron injection property of the organic electroluminescent element by forming an electron injection layer on the inorganic oxide layer. For example, Non-Patent Document 4 describes an organic electroluminescent element having an electron injection layer made of polyethyleneimine. Non-Patent Document 5 describes that amine is effective in improving the injection rate of electrons. Non-Patent Documents 6, 7, and 8 describe the effect of amino groups on electron injection at the interface between an electrode and an organic layer.

Carsten Walzer and three others “Chemical Review” 107, 2007, p1233-1271 Pen Way, 3 others "Journal of the American Chemical Society", Vol. 132, 2010, p8852 Jiangshan Chen and six others, “Journal of Materials Chemistry”, Vol. 22, 2012, p5164-5170 Hyosun Choi and 8 others "Advanced Materials", Vol. 23, 2011, p2759 21 people outside of Yinhua Zho, “Science”, Volume 336, 2012, p327 Five people from Young-Hoon Kim, “Advanced Functional Materials”, 2014, DOI: 10.1002 / adfm. 201304163 Stephan Forful, four others "Advanced Materials", 2014, DOI: 10.1002 / adma. 201304666 Stephan Forful, five others "Advanced Materials", Vol. 26, 2014, DOI: 10.1002 / adma. 201400332 Pen Way, 3 others "Journal of the American Chemical Society", Vol. 132, 2010, p8852

As described above, studies have been made to improve the electron injection property of the organic electroluminescent device, but there is room for further improvement of the device to further improve the electron injection property and have excellent light emission efficiency. Further, the organic electroluminescence device includes an organic electroluminescence device having a reverse structure in which a cathode is formed on a substrate as described in Non-Patent Document 3, and an organic electroluminescence device having a forward structure in which an anode is formed on the substrate. There is an element, and it is also necessary to examine the optimum layer structure in accordance with the structure of the organic electroluminescent element.

The present invention has been made in view of the above-described situation, and provides an organic electroluminescence device having a forward structure in which an anode is formed on a substrate, and has an excellent electron injection property and an excellent luminous efficiency. For the purpose.

The present inventor has studied various organic electroluminescent elements having a forward structure having excellent electron injection properties and excellent luminous efficiency, and in the laminated structure between the cathode and the anode, the layer adjacent to the cathode is It has been found that an organic electroluminescence device having excellent electron injection property and excellent luminous efficiency can be obtained by including the first material which is an organic material having an acid dissociation constant pKa of 1 or more. .

That is, the present invention is an organic electroluminescent device having a structure in which a plurality of layers including a light emitting layer are laminated between a cathode and an anode formed on a substrate, and among the plurality of laminated layers, The organic electroluminescence device is characterized in that the layer adjacent to the cathode contains a first material which is an organic material having an acid dissociation constant pKa of 1 or more.

The first material is one or more compounds selected from the group consisting of tertiary amines, phosphazene compounds, guanidine compounds, heterocyclic compounds containing amidine structures, hydrocarbon compounds having ring structures, and ketone compounds. Preferably there is.

The organic electroluminescent element has a layer containing a second material that transports electrons between the light emitting layer and the layer containing the first material, or the first material and the first material between the light emitting layer and the cathode. It is preferable to have a layer containing two materials.

The second material contains one or more compounds selected from the group consisting of boron-containing compounds represented by the following general formulas (14), (37), (39), (16) and (18). Is preferred.

(In the general formula (14), the dotted circular arc indicates that a ring structure is formed together with the skeleton part represented by the solid line. The dotted line part in the skeleton part represented by the solid line is a pair connected by the dotted line The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ¹ and Q ² are the same. or different, is a linking group in the skeleton moiety represented by the solid line, forms a ring structure at least partially with a circular arc portion of the dotted line, which may have a substituent .X ^1, X ^2, X ³ and X ⁴ are the same or different and each represents a hydrogen atom or a monovalent substituent serving as a substituent of the ring structure, and a plurality of X ³ and X ⁴ may be bonded to the ring structure forming the dotted arc portion. .n ¹ represents an integer of 2 to 10 .Y ¹ is a direct bond or ^{n 1} monovalent A linking group, each independently and structural parts other than ^{Y 1} present ^{one n,} ring structure to form an arc portion of the dotted ^line, either in ^{Q 1, Q 2, X 1} , X 2, X 3, X 4 Represents that they are joined at one location.)

(In the general formula (37), the dotted arcs are the same or different and represent that a ring structure is formed together with the skeleton part represented by the solid line. The dotted line part in the skeleton part represented by the solid line represents the dotted line. a pair of atoms connected by representing that may be linked by a double bond. arrow from nitrogen atom to boron atom, .R ¹⁸ ~ indicating that the nitrogen atom is coordinated to a boron atom R ^{21 s} are the same or different and each represents a hydrogen atom, a monovalent substituent that serves as a substituent of a ring structure, a divalent group, or a direct bond, R ¹⁸ , R ^19, and R ²¹ are each a dotted line A plurality of R ²⁰ may be bonded to the pyridine ring structure, and the ring to which R ²¹ is bonded is an aromatic heterocyclic ring. there .n ⁶ is an integer from 1 to 4 .n ⁷ is 0 or 1 If n ⁷ is 1, ^{Y 2} are, ^{n 6} divalent linking group, or represents a direct bond, independently and structural parts other than the ^{Y 2} present ^{six n, R 18, R 19,} R 20, ^or, if .n ⁷ indicating that it is bound by any one location in ^{R 21} is 0, ^{n 6} is ^1, at least one of R 18 ^{to R 21} is a substituent of the ring structure And a monovalent substituent.

(In the general formula (39), a dotted circular arc represents that a ring structure is formed together with a skeleton part represented by a boron atom or a solid line, and the ring structure is the same or different and is composed of one ring. The dotted structure in the skeleton represented by the solid line may be a double pair of atoms connected by a dotted line. An arrow from a nitrogen atom to a boron atom indicates that the nitrogen atom is coordinated to the boron atom, and Q ⁷ is a link in the skeleton part represented by a solid line. R ²² and R ²³ are the same or different and may be substituted with a hydrogen atom or a ring structure, at least part of which forms a ring structure together with a dotted arc portion. Monovalent substituent, divalent group, or direct bond as a base And a plurality bonded good .R ²⁴ and R ²⁵ even if the ring structure to form an arc portion of the dotted line, the same or different and each represents a hydrogen atom, a monovalent substituent, a divalent group or a direct R ²⁴ and R ²⁵ are bonded to each other and do not form a ring structure with a skeleton represented by a double line, and n ⁸ is an integer of 1 to 4. n ⁹ is If .n ⁹ is 1 is 0 or 1, ^{Y 3} is, ^{n 8} divalent linking group, or represents a direct bond, independently and structural parts other than ^{Y 3} present ^{eight n, R 22,} It represents bonding at any one of R ²³ , R ²⁴ , or R ^25. )

(In the general formula (16), a dotted circular arc indicates that a ring structure is formed together with a skeleton portion represented by a solid line. A dotted line portion in the skeleton portion represented by a solid line is a pair connected by a dotted line. The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ³ and Q ⁴ are the same. or different, is a linking group in the skeleton moiety represented by the solid line, forms a ring structure at least partially with a circular arc portion of the dotted line, which may have a substituent .X ^5, X ⁶ is X ⁷ and X ⁸ are the same or different and each represents a hydrogen atom or a monovalent substituent serving as a substituent of the ring structure, and X ⁷ and X ⁸ are the same or different and represent an electron transporting property 1 serving as a substituent of the ring structure. represents the valence of the substituent ^{.X 5, X 6,} X ⁷ and ^{X 8} are each point The ring structure to form an arc portion may be a plurality bonds.)

(In the general formula (18), a dotted circular arc indicates that a ring structure is formed together with a skeleton portion represented by a solid line. A dotted line portion in the skeleton portion represented by a solid line is a pair connected by a dotted line. The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ⁵ and Q ⁶ are the same. Alternatively, it is a linking group in the skeleton part represented by a solid line, and at least a part thereof forms a ring structure together with a dotted arc part, and may have a substituent group, X ⁹ , X ¹⁰ , X ¹¹ and X ¹² are the same or different and each represents a hydrogen atom, a monovalent substituent that serves as a substituent of the ring structure, or a direct bond, and a plurality of X ¹¹ and X ¹² are bonded to the ring structure forming the dotted arc portion. which may be .A ¹ are the same or different, Table divalent radical Structural units in parentheses marked with .n ^{2 is, X 9, X 10, X} 11 and any two is bonded to adjacent structural units ^.n 2, ^{n 3} of ^{X 12} are each independently Are the same or different and represent a number of 1 or more.)

The second material is any one boron-containing compound represented by the following general formula (1), (14-2), or (21-2) or a phosphine oxide derivative represented by the following general formula (2). Is preferred.

(In the general formula (21-2), ^{n 4} represents the number of 1 or more.)

The acid dissociation constant pKa of the first material is preferably 11 or more.

The present invention is also a display device comprising the organic electroluminescent element of the present invention.

This invention is also an illuminating device provided with the organic electroluminescent element of this invention.

The present invention is also a method for producing an organic electroluminescent device having a structure in which a plurality of layers including a light emitting layer are laminated between a cathode and an anode formed on a substrate, the production method comprising: An organic electroluminescence device comprising: a step of forming a layer containing a first material that is an organic material having a dissociation constant pKa of 1 or more; and a step of forming a cathode on the layer containing the first material It is also a manufacturing method.

The above manufacturing method includes a step of forming a layer containing a second material that transports electrons after forming a light emitting layer, and an organic material having an acid dissociation constant pKa of 1 or more after forming the layer containing the second material Preferably, the method includes a step of forming a layer including the first material, or a step of forming a layer including the first material and the second material after forming the light emitting layer.

The step of forming the layer containing the first material is preferably a step of applying a coating composition containing the first material on the surface to be formed.

The step of forming the layer containing the first material is preferably a step of forming a film on the surface to be formed with the vapor of the first material.

The step of forming the layer containing the second material is preferably a step of applying a coating composition containing the second material on the surface to be formed.

The step of forming the layer containing the first material and the second material is preferably a step of applying a coating composition containing the first material and the second material on the surface to be formed.

In the organic electroluminescent device of the present invention, the layer adjacent to the cathode contains a first material that is an organic material having an acid dissociation constant pKa of 1 or more, so that the electron injecting property is excellent. Therefore, it can be suitably used as a material for display devices and lighting devices.

It is the schematic which showed an example of the laminated structure of the organic electroluminescent element of this invention. 4 is a diagram showing ¹ H-NMR measurement results of a boron-containing compound A synthesized in Synthesis Example 1. FIG. FIG. 4 is a diagram showing measurement results of voltage-current density / luminance characteristics of the organic electroluminescent element produced in Example 1. 6 is a graph showing measurement results of voltage-current density / luminance characteristics of an organic electroluminescent element produced in Example 2. FIG. 6 is a diagram showing measurement results of voltage-current density / luminance characteristics of an organic electroluminescent element produced in Comparative Example 1. FIG. 6 is a graph showing measurement results of voltage-current density / luminance characteristics of an organic electroluminescent element produced in Example 3. FIG. It is the figure which showed the measurement result of the voltage-current density / luminance characteristic of the organic electroluminescent element produced in Example 4. FIG. 6 is a graph showing measurement results of voltage-current density / luminance characteristics of an organic electroluminescent element produced in Example 5. FIG.

The present invention is described in detail below.
A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

1. Organic electroluminescent device The organic electroluminescent device of the present invention is characterized in that the layer adjacent to the cathode contains a first material which is an organic material having an acid dissociation constant pKa of 1 or more. An organic material having an acid dissociation constant pKa of 1 or more has the ability to extract protons (H ⁺ ) from other compounds, and the layer containing the first material is disposed at a position adjacent to the cathode, so that The device is excellent in electron injection property.
The first material may be an organic material having an acid dissociation constant pKa of 1 or more, but the acid dissociation constant pKa of the organic material is preferably 5 or more, and more preferably 11 or more.
In the present invention, “pKa” usually means “acid dissociation constant in water”, but what cannot be measured in water means “acid dissociation constant in dimethyl sulfoxide (DMSO)” and cannot be measured even in DMSO. What is meant is “acid dissociation constant in acetonitrile”. Preferably, it means “acid dissociation constant in water”.

The layer containing the first material may be a layer made of only the first material, or may contain other components. Examples of other components include a second material that transports electrons. In this case, a layer including the first material and the second material is formed.

In the organic electroluminescent element of the present invention, a layer containing a second material for transporting electrons is provided between the light emitting layer and the layer containing the first material, or the first material is provided between the light emitting layer and the cathode. It is preferable to have a layer including a material and a second material.
When the element has a layer containing a second material that transports electrons between the light emitting layer and the layer containing the first material, an electron injecting layer and an electron transporting property are formed from the cathode toward the light emitting layer. These layers are present in this order, and the organic electroluminescent device has more excellent characteristics. More preferably, the layer containing the first material and the layer containing the second material for transporting electrons are adjacent to each other, and the electron transporting layer and the electron injecting layer are adjacent to each other so that the light emitting layer is formed from the cathode. Electrons are transported more efficiently.
When the layer containing the first material contains a second material that transports electrons, the layer containing the first material exhibits excellent electron injection properties by extracting protons from the second material. .
The layer containing the second material may be a layer made of only the second material, or may contain other components other than the first material.

<First material>
The first material is one or more compounds selected from the group consisting of tertiary amines, phosphazene compounds, guanidine compounds, heterocyclic compounds containing amidine structures, hydrocarbon compounds having ring structures, and ketone compounds. Preferably there is.
The tertiary amine (tertiary amine derivative) may be a chain or cyclic amine compound, and if it is cyclic, it may be a heterocyclic amine compound, an aliphatic amine or an aromatic amine. Heterocyclic amine compounds such as amines may also be used. The tertiary amine preferably has 1 to 4 amino groups, more preferably 1 or 2 amino groups. Moreover, as an amine compound, the compound which has an alkyl group, an alkylamino group, and an alkoxy group may be sufficient. Specific examples include (mono, di, tri) alkylamines; aromatic amines having 1 to 3 alkylamino groups; aromatic amines having 1 to 3 alkoxy groups.

As said tertiary amine, the thing which does not contain a primary amine and a secondary amine is preferable. Specifically, as the tertiary amine used for the first material, dialkylaminopyridine such as dimethylaminopyridine (DMAP) represented by the following general formula (3) or (4), triethylamine represented by the following general formula (5) An amine having a structure represented by NR ¹ R ² R ³ such as R ¹ , R ² and R ³ are the same or different and each represents a hydrocarbon group which may have a substituent; Examples thereof include acridine orange (AOB) represented by the following general formula (43). As said hydrocarbon group, a C1-C30 thing is preferable, A C1-C8 thing is more preferable, A C1-C4 thing is more preferable, A C1-C2 thing is still more preferable. . When a hydrocarbon group has a substituent, it is preferable that it is the said carbon number as a whole also including a substituent. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, and an alkynyl group, and an alkyl group is preferable. Examples of the substituent in the hydrocarbon group having a substituent include a halogen atom, a heterocyclic group, a cyano group, a hydroxyl group, an alkoxy group, an aryloxy group, and an amino group. As the dimethylaminopyridine, the position bonded to the pyridine ring of the dimethylamino group which is an electron donating group is preferably the 2-position (2-DMAP) or the 4-position (4-DMAP). In particular, 4-dimethylaminopyridine in which a dimethylamino group is bonded to the 4-position of the pyridine ring has a high pKa, and a long lifetime when an organic thin film containing this is used as an electron injection layer of an organic electroluminescence device. Is preferable.

As the tertiary amine used for the first material, an alkoxypyridine derivative such as a methoxypyridine derivative can also be used. As an alkoxy group, a C1-C30 alkoxy group is preferable, a C1-C8 alkoxy group is more preferable, a C1-C4 alkoxy group is more preferable, and a 1 or 2 alkoxy group is still more preferable. . The alkoxypyridine derivative also includes a compound having a structure in which one or more hydrogen atoms of alkoxypyridine are substituted with a substituent. Examples of the substituent are the same as those of the tertiary amine hydrocarbon group.
Examples of the methoxypyridine derivative include 4-methoxypyridine (4-MeOP) represented by the following general formula (6) in which the position bonded to the pyridine ring of the methoxy group is the 4-position or the following general formula (7 It is preferable that it is 3-methoxy pyridine (3-MeOP) shown by this. In particular, 4-methoxypyridine having a methoxy group bonded to the 4-position of the pyridine ring is preferable because of high pKa.
As the tertiary amine, it is preferable to use one or two or more kinds selected from a heterocyclic aromatic amine having a dialkylamino group and / or an alkoxy group, and a trialkylamine, and a dialkylaminopyridine, a trialkylamine, It is particularly preferable to use one or more selected from alkoxypyridine derivatives from the viewpoint of improving electron injection properties and lifetime.

As the first material, a heterocyclic compound containing an amidine structure is also used. Here, the amidine structure is a structure represented by R ¹ —C (═NR ² ) —NR ³ R ⁴ (where R ^{1 to} R ³ are the same or different and represent a hydrogen atom or a hydrocarbon group). ). Examples of the heterocyclic compound containing an amidine structure include diazabicyclononene derivatives and diazabicycloundecene derivatives.

Examples of the diazabicyclononene derivative include 1,5-diazabicyclo [4.3.0] nonene-5 (DBN) represented by the following general formula (8). DBN is preferable because a long life can be obtained when an organic thin film containing the DBN is used as an electron injection layer of an organic electroluminescence device.
Examples of the diazabicycloundecene derivative include 1,8-diazabicyclo [5.4.0] undecene-7 (DBU) represented by the following general formula (9). The diazabicyclononene derivative includes a compound having a structure in which one or more hydrogen atoms of diazabicyclononene are substituted with a substituent, and the diazabicycloundecene derivative includes diazabicycloundecene hydrogen. Also included are compounds having a structure in which one or more of the atoms are substituted with a substituent. Examples of the substituent are the same as those of the tertiary amine hydrocarbon group.

The phosphazene compound (phosphazene base derivative) is, for example, a compound having a structure represented by the following general formula (35).

R ⁵ represents a hydrogen atom or a hydrocarbon group, R ^{6 to} R ⁸ are a hydrogen atom, a hydrocarbon group, —NR′R ″ (where R ′ and R ″ are independently a hydrogen atom, Represents a hydrogen group.) Or a group represented by the following formula (36), and n represents a number of 1 to 5.

In the above formula (36), R ^{9 to} R ¹¹ represent a hydrogen atom, a hydrocarbon group, or —NR′R ″ (where R ′ and R ″ each independently represent a hydrogen atom or a hydrocarbon group). M represents a number of 1 to 5.
As a hydrocarbon group in the said Formula (35), (36), a C1-C8 group is preferable and a C1-C4 group is preferable. The hydrocarbon group is preferably an alkyl group. R ⁵ is particularly preferably a tertiary butyl group.
Examples of the phosphazene base derivative include Phosphazene base P2-t-Bu represented by the following general formula (10).

The said guanidine compound is a compound containing the structure represented by the following general formula (42).

(In General Formula (42), R ^{13 to} R ¹⁷ are the same or different and each represents a hydrogen atom or a hydrocarbon group, and two or more of R ^{13 to} R ¹⁷ are bonded to form a cyclic structure. May be good.)
As the guanidine compound, a guanidine cyclic derivative or the like can be used. Examples of the guanidine cyclic derivative include 7-methyl-1,5,7-triazabicyclo [4.4.0] dec-5-ene (MTBD) represented by the following general formula (11), and the following general formula (12). 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) etc. which are shown by these.

The hydrocarbon compound having the above ring structure is preferably a compound having a 5-membered ring or a 6-membered ring as the ring structure, or a ring structure in which a 5-membered ring and a 6-membered ring are condensed, or a plurality of 6-membered rings are condensed. A compound having a cyclic ring structure is also preferred. Examples of the 5-membered ring include a cyclopentane ring and a cyclopentadiene ring. Examples of the 6-membered ring include a benzene ring.
As the hydrocarbon compound having a ring structure, a compound having only a ring structure, a compound having a structure in which an alkyl group having 1 to 20, preferably 1 to 10, more preferably 1 to 5 carbon atoms is bonded to the ring structure, or a plurality of rings Compounds having a structure in which the structure is bonded directly or via a hydrocarbon linking group having 1 to 20, preferably 1 to 10, more preferably 1 to 5 carbon atoms are preferred. Specific examples of the hydrocarbon compound having a ring structure include the following general formulas (44) to (57). Ph in the general formulas (50) and (57) represents a phenyl group.

As said ketone compound, a C2-C30 ketone is preferable and may have a cyclic structure. Specifically, methyl ethyl ketone (MEK), acetone, diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), diisobutyl ketone (DIBK), 3,5,5-trimethylcyclohexanone, diacetone alcohol, cyclopenta Non, cyclohexanone and the like are exemplified.
Further, as the first material, any one or more selected from tertiary amine derivatives, methoxypyridine derivatives, diazabicyclononene derivatives, diazabicycloundecene derivatives, phosphazene base derivatives, and guanidine cyclic derivatives may be used. Good.

<Second material>
The second material may be any material that transports electrons, and is preferably an organic material. More preferably, it is an organic material having a lowest unoccupied orbital (LUMO) level of 2.0 eV to 4.0 eV, and among them, an n-type organic semiconductor material having a LUMO level of 2.5 eV to 3.5 eV. For example, any of the conventionally known materials shown below may be used as the material for the electron transport layer of the organic electroluminescent element, but among these, materials that satisfy the above LUMO level requirements are preferable.

Specific examples of the second material include phosphine oxide derivatives such as phenyl-dipyrenylphosphine oxide (POPy ₂ ), tris-1,3,5- (3 ′-(pyridin-3 ″ -yl). Pyridine derivatives such as phenyl) benzene (TmPhPyB), quinoline derivatives such as (2- (3- (9-carbazolyl) phenyl) quinoline (mCQ)), 2-phenyl-4,6-bis (3,5 -Pyrimidine derivatives such as dipyridylphenyl) pyrimidine (BPyPPM), pyrazine derivatives, phenanthroline derivatives such as bathophenanthroline (BPhen), 2,4-bis (4-biphenyl) -6- (4 '-(2-pyridinyl) -4-biphenyl)-[1,3,5] triazine (MPT) and other triazine derivatives, 3-phenyl Triazole derivatives such as 4- (1′-naphthyl) -5-phenyl-1,2,4-triazole (TAZ), oxazole derivatives, 2- (4-biphenylyl) -5- (4-tert-butylphenyl- Oxadiazole derivatives such as 1,3,4-oxadiazole) (PBD), 2,2 ′, 2 ″-(1,3,5-bentriyl) -tris (1-phenyl-1-H— Imidazole derivatives such as benzimidazole (TPBI), aromatic tetracarboxylic anhydrides such as naphthalene and perylene, bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (Zn (BTZ) ₂ ), tris (8- hydroxyquinolinato) aluminum (Alq ₃₎ various metal complexes typified by 2,5-bis (6 '- (2', 2 '' - bipyridyl)) - 1,1 Organosilane derivatives typified by silole derivatives such as dimethyl-3,4-diphenylsilole (PyPySPyPy), Japanese Patent Application No. 2012-228460, Japanese Patent Application No. 2015-503053, Japanese Patent Application No. 2015-038772, Japanese Patent Application No. Examples thereof include boron-containing compounds described in 2015-081109, and one or more of these can be used.

Among the second material, phosphine oxide derivatives such as Popy _2, boron-containing compounds, metal complexes such as Alq _3, it is preferable to use pyridine derivatives such as TmPhPyB. Among these second materials, in particular, the second material is represented by any one type of boron-containing compound represented by the above general formula (1) (14-2) (21-2) or the above general formula (2). The phosphine oxide derivative is preferable.

As a boron containing compound used for the said 2nd material, the boron containing compound represented by following General formula (14) is mentioned, for example.

(In the general formula (14), the dotted circular arc indicates that a ring structure is formed together with the skeleton part represented by the solid line. The dotted line part in the skeleton part represented by the solid line is a pair connected by the dotted line The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ¹ and Q ² are the same. or different, is a linking group in the skeleton moiety represented by the solid line, forms a ring structure at least partially with a circular arc portion of the dotted line, which may have a substituent .X ^1, X ^2, X ³ and X ⁴ are the same or different and each represents a hydrogen atom or a monovalent substituent serving as a substituent of the ring structure, and a plurality of X ³ and X ⁴ may be bonded to the ring structure forming the dotted arc portion. .n ¹ represents an integer of 2 to 10 .Y ¹ is a direct bond or ^{n 1} monovalent A linking group, each independently and structural parts other than ^{Y 1} present ^{one n,} ring structure to form an arc portion of the dotted ^line, either in ^{Q 1, Q 2, X 1} , X 2, X 3, X 4 Represents that they are joined at one location.)

In the general formula (14), the dotted circular arc is a skeleton part represented by a solid line, that is, a part of the skeleton part that connects the boron atom, Q ^1, and the nitrogen atom or the skeleton part that connects the boron atom and Q ² . It represents that a ring structure is formed together with a part. This is because the compound represented by the general formula (14) has at least four ring structures in the structure, and in the general formula (14), a skeleton portion that connects a boron atom, Q ^1, and a nitrogen atom, and boron It represents that the skeleton part connecting the atom and Q ² is included as a part of the ring structure. Incidentally, the ring structure to couple the X ^1, the ring structure skeleton contains no atoms other than carbon atoms, and is preferably made of carbon atoms.
In the general formula (14), skeleton moiety represented by the solid line, i.e. the dotted lines boron atom to Q ^1, a nitrogen atom and a backbone moiety and the boron atom, Q ² and skeletal portion connecting the connecting in, each of the skeleton This means that a pair of atoms connected by a dotted line in a part may be connected by a double bond.

In the general formula (14), the arrow from the nitrogen atom to the boron atom represents that the nitrogen atom is coordinated to the boron atom. Here, coordinating means that the nitrogen atom acts on the boron atom in the same manner as the ligand and has a chemical effect, and is a coordinate bond (covalent bond). Or a coordinate bond may not be formed. Preferably, it is a coordinate bond.

In the general formula (14), Q ¹ and Q ² are the same or different and are a linking group in a skeleton part represented by a solid line, and at least a part forms a ring structure together with a dotted arc part And may have a substituent. This indicates that Q ¹ and Q ² are each incorporated as part of the ring structure.

In the general formula (14), X ¹ , X ² , X ³ and X ⁴ are the same or different and each represents a hydrogen atom or a monovalent substituent which is a substituent of a ring structure, and a dotted arc portion A plurality of the ring structures may form a bond. That is, when X ¹ , X ² , X ³ and X ⁴ are hydrogen atoms, the compound represented by the general formula (14) has X ¹ , X ² , X ³ and X ⁴ in the structure of the compound. 4 ring structures have no substituent, and when any or all of X ¹ , X ² , X ³ and X ⁴ are monovalent substituents, Either or both have a substituent. In that case, the number of substituents in one ring structure may be one, or two or more.
In the present specification, the substituent means a group including an organic group containing carbon and a group not containing carbon such as a halogen atom and a hydroxy group.

In the general formula (14), ^{n 1} represents an integer of 2 to 10, ^{Y 1} is a direct bond or ^{n 1} valent connecting group. That is, in the compound represented by the general formula (14), Y ¹ is a direct bond, and two structural portions other than Y ¹ are each independently formed as a dotted arc portion. ^{, Q 1, Q 2, X} 1, X 2, X 3, or attached at any one location in the ^{X 4,} or, ^{Y 1} is ^{n 1} valent linking group, in the general formula (14) There are a plurality of structural parts other than Y ¹ , and they are bonded via Y ¹ which is a linking group.

In the general formula (14), when Y ¹ is a direct bond, the general formula (14) is a ring structure that forms a dotted arc portion of one of the two structural portions other than Y ¹ . Any one of Q ¹ , Q ² , X ¹ , X ² , X ³ , X ⁴ and the other ring structure forming a dotted arc part, Q ¹ , Q ² , X ¹ , X ² , It represents that either one of X ³ and X ⁴ is directly bonded. The bonding position is not particularly limited, but the ring to which ^one X ¹ of the structural portion other than Y ¹ is bonded or the ring to which X ² is bonded and the ring to which the other X ¹ is bonded or X It is preferable that the ring to which ² is bonded is directly bonded. More preferably, the ring to which one X ² of the structural portion other than Y ¹ is bonded and the ring to which the other X ² is bonded are directly bonded. In this case, the structure of the two structural portions other than Y ¹ may be the same or different.

In the general formula (14), Y ¹ is a n ¹ valent connecting group, structural parts other than Y ¹ in the general formula (14) there is a plurality, through a Y ¹ they are linking group In the case of bonding, it is more preferable than the structure in which structural parts other than Y ¹ are directly bonded, because it is more resistant to oxidation and the film-forming property is improved.

Incidentally, ^{Y 1} is the case of ^{n 1} valent connecting group, ^{Y 1} is independently a structural part other than ^{Y 1} present ^{one n,} ring structure to form an arc portion of the dotted ^{line, Q} 1, Q ² , X ¹ , X ² , X ³ , and X ⁴ are bonded at any one position. This structural part other than ^{Y 1} is a ring structure to form an arc portion of the dotted ^{line, Q 1, Q 2, X} 1, X 2, X 3, at any one point in ^{X 4} are bonded to ^{Y 1} may be Re, the binding site of the Y ¹ structural parts other than Y ¹ is an independently to each structural part other than Y ¹ present ^one n, to all be the same site, some The same part may be sufficient, and all different parts may be sufficient.

The bonding position is not particularly limited, but all n ¹ structural portions other than Y ¹ are bonded to Y ¹ through a ring to which X ¹ is bonded or a ring to which X ² is bonded. Is preferred. More preferably, all of the structural parts other than Y ¹ present ^one n is that which is bound to Y ¹ in ring X ² is bonded.
The structure of the structural parts other than Y ¹ present ^one n may all be the same, to some may be the same or different all.

When Y ¹ in the general formula (14) is n ¹ valent connecting group, Examples of the linking group, for example, have a substituent which may linear, branched or cyclic hydrocarbon group, Examples include a group containing a hetero element which may have a substituent, an aryl group which may have a substituent, and a heterocyclic group which may have a substituent. Among these, a group having an aromatic ring such as an aryl group which may have a substituent and a heterocyclic group which may have a substituent is preferable. That is, Y ¹ in the general formula (14) is also a group having an aromatic ring, which is one of the preferred embodiments of the present invention.
Furthermore, Y ¹ may be a linking group having a structure in which a plurality of linking groups described above are combined.

The chain, branched chain or cyclic hydrocarbon group is preferably a group represented by any of the following formulas (2-1) to (2-8). Among these, the following formulas (2-1) and (2-7) are more preferable.
The group containing a hetero element is preferably a group represented by any of the following formulas (2-9) to (2-13). Among these, the following formulas (2-12) and (2-13) are more preferable.

The aryl group is preferably a group represented by any of the following formulas (2-14) to (2-20). Among these, the following formulas (2-14) and (2-20) are more preferable.

The heterocyclic group is preferably a group represented by any of the following formulas (2-21) to (2-33). Among these, the following formulas (2-23) and (2-24) are more preferable.

Examples of the substituent of the chain, branched or cyclic hydrocarbon group, hetero element-containing group, aryl group, and heterocyclic group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom halogen atom; A haloalkyl group such as a group, a difluoromethyl group or a trifluoromethyl group; a linear or branched group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group or a tert-butyl group Chain alkyl group; C5-C7 cyclic alkyl group such as cyclopentyl group, cyclohexyl group, cycloheptyl group; methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, tert-butoxy group, C1-C20 straight chain such as pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group Or a branched alkoxy group; a nitro group; a cyano group; a dialkylamino group having an alkyl group having 1 to 10 carbon atoms such as a methylamino group, an ethylamino group, a dimethylamino group, or a diethylamino group; a diphenylamino group, a carbazolyl group, or the like An acetyl group, a propionyl group, a butyryl group and the like; a vinyl group, a 1-propenyl group, an allyl group, a styryl group and the like, an alkenyl group having 2 to 30 carbon atoms; an ethynyl group, a 1-propynyl group, An alkynyl group having 2 to 30 carbon atoms such as a propargyl group; an aryl group optionally substituted with a halogen atom, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group; a halogen atom, an alkyl group, an alkoxy group, an alkenyl group, A heterocyclic group optionally substituted by an alkynyl group; N, N-dimethylcarbamo N, N-dialkylcarbamoyl groups such as N group, N, N-diethylcarbamoyl group; dioxaborolanyl group, stannyl group, silyl group, ester group, formyl group, thioether group, epoxy group, isocyanate group, etc. It is done. These groups may be substituted with a halogen atom, a hetero element, an alkyl group, an aromatic ring or the like.

Among these, as a substituent which the linear, branched or cyclic hydrocarbon group in Y ¹ , a group containing a hetero element, an aryl group, or a heterocyclic group has, a halogen atom, a straight chain having 1 to 20 carbon atoms A linear or branched alkyl group, a linear or branched alkoxy group having 1 to 20 carbon atoms, an aryl group, a heterocyclic group, or a diarylamino group is preferable. More preferred are an alkyl group, an aryl group, an alkoxy group, and a diarylamino group.
When the chain, branched chain, or cyclic hydrocarbon group in Y ¹ above, a group containing a hetero element, an aryl group, or a heterocyclic group has a substituent, the position and number of the substituent bonded are not particularly limited.

N ¹ in the general formula (14) represents an integer of 2 to 10, and preferably an integer of 2 to 6. More preferably, it is an integer of 2-5, More preferably, it is an integer of 2-4, Most preferably, it is 2 or 3 from a soluble viewpoint to a solvent. Most preferably 2. That is, the boron-containing compound represented by the general formula (14) is most preferably a dimer.

Examples of Q ¹ and Q ² in the general formula (14) include structures represented by the following formulas (3-1) to (3-8);

The above formula (3-2) is a structure in which two hydrogen atoms are bonded to a carbon atom and further three atoms are bonded. However, the three atoms bonded to the carbon atom other than the hydrogen atom are: All are atoms other than a hydrogen atom. Among the above formulas (3-1) to (3-8), any of (3-1), (3-7), and (3-8) is preferable. More preferably, it is (3-1). That is, it is also one of the preferred embodiments of the present invention that Q ¹ and Q ² are the same or different and represent a linking group having 1 carbon atom.

In the general formula (14), the ring structure formed by the dotted arc and a part of the skeleton represented by the solid line is a cyclic structure as long as the skeleton of the ring structure to which X ¹ is bonded is composed of carbon atoms. If it is, it will not be restrict | limited in particular.

In the general formula (14), when Y ¹ is a direct bond and n ¹ is 2, examples of the ring to which X ¹ is bonded include a benzene ring, a naphthalene ring, an anthracene ring, a tetracene ring, Pentacene ring, triphenylene ring, pyrene ring, fluorene ring, indene ring, thiophene ring, furan ring, pyrrole ring, benzothiophene ring, benzofuran ring, indole ring, dibenzothiophene ring, dibenzofuran ring, carbazole ring, thiazole ring, benzothiazole ring , Oxazole ring, benzoxazole ring, imidazole ring, pyrazole ring, benzimidazole ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, quinoline ring, isoquinoline ring, quinoxaline ring, benzothiadiazole ring, phenanthridine ring, oxadi Azole ring, thia Azole ring are exemplified, each of which is represented by the following formula (4-1) to (4-36).

Among these, those in which the ring structure skeleton is composed of only carbon atoms are preferable, and a benzene ring, naphthalene ring, anthracene ring, tetracene ring, pentacene ring, triphenylene ring, pyrene ring, fluorene ring, and indene ring are preferable. More preferred are a benzene ring, a naphthalene ring and a fluorene ring, and still more preferred is a benzene ring.

In the general formula (14), when Y ¹ is a direct bond and n ¹ is 2, examples of the ring to which X ² is bonded include an imidazole ring, a benzimidazole ring, a pyridine ring, and a pyridazine ring. , Pyrazine ring, pyrimidine ring, quinoline ring, isoquinoline ring, phenanthridine ring, quinoxaline ring, benzothiadiazole ring, thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, oxadiazole ring, thiadiazole ring. These are respectively represented by the following formulas (5-1) to (5-17).

Incidentally, * mark in the following formulas (5-1) to (5-17) constitute a ^{ring X 1} is attached and the boron atom and ^{Q 1,} the nitrogen atom in the above general formula (14) It represents that the carbon atom which comprises the skeleton part which connects is couple | bonded with any one of the carbon atoms marked with *. Further, it may be condensed with another ring structure at a position excluding the carbon atom marked with *. Among these, a pyridine ring, a pyrimidine ring, a quinoline ring, and a phenanthridine ring are preferable. More preferred are a pyridine ring, a pyrimidine ring, and a quinoline ring. More preferably, it is a pyridine ring.

In the general formula (14), when Y ¹ is a direct bond and n ¹ is 2, the ring to which X ³ is bonded and the ring to which X ⁴ is bonded include the above formula ( The ring represented by 4-1)-(4-33) is mentioned. Among these, a benzene ring, a naphthalene ring, and a benzothiophene ring are preferable. More preferably, it is a benzene ring.

In the general formula (14), X ¹ , X ² , X ³ and X ⁴ are the same or different and each represents a hydrogen atom or a monovalent substituent that serves as a substituent of a ring structure. The monovalent substituent is not particularly limited, and examples of X ¹ , X ² , X ³ and X ⁴ include a hydrogen atom, an aryl group which may have a substituent, a heterocyclic group, and an alkyl group. Alkenyl group, alkynyl group, alkoxy group, aryloxy group, arylalkoxy group, silyl group, hydroxy group, amino group, alkylamino group, arylamino group, halogen atom, carboxyl group, thiol group, epoxy group, acyl group, Oligoaryl group which may have a substituent, monovalent oligoheterocyclic group, alkylthio group, arylthio group, arylalkyl group, arylalkoxy group, arylalkylthio group, azo group, stannyl group, phosphino group, substituent Arylphosphino group which may have an alkylphosphino group which may have a substituent, aryl Phosphinyl group, alkylphosphinyl group which may have a substituent, silyloxy group, aryloxycarbonyl group which may have a substituent, alkoxycarbonyl group which may have a substituent, substituent A carbamoyl group which may have a substituent, an arylcarbonyl group which may have a substituent, an alkylcarbonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, a substituent Alkylsulfonyl group which may have a group, arylsulfinyl group which may have a substituent, alkylsulfinyl group which may have a substituent, formyl group, cyano group, nitro group, arylsulfonyloxy Group, alkylsulfonyloxy group; methanesulfonate group, ethanesulfonate group, trifluoromethanesulfonate group Alkylsulfonate groups such as benzenesulfonate groups and p-toluenesulfonate groups; arylalkylsulfonate groups such as benzylsulfonate groups, boryl groups, sulfonium methyl groups, phosphonium methyl groups, phosphonate methyl groups, aryl sulfonate groups, aldehydes Group, acetonitrile group and the like.

Examples of the substituent in X ¹ , X ² , X ³ and X ⁴ include a fluorine atom, a chlorine atom, a bromine atom, a halogen atom of iodine atom; a methyl chloride group, a methyl bromide group, a methyl iodide group, a fluoromethyl group Haloalkyl groups such as difluoromethyl group and trifluoromethyl group; straight chain having 1 to 20 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group and tert-butyl group Linear or branched alkyl group; C5-C7 cyclic alkyl group such as cyclopentyl group, cyclohexyl group, cycloheptyl group; methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, tert -Carbon number of butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, etc. A linear or branched alkoxy group of -20; a hydroxy group; a thiol group; a nitro group; a cyano group; an amino group; an azo group; a carbon number of 1 such as a methylamino group, an ethylamino group, a dimethylamino group, a diethylamino group Mono- or dialkylamino group having an alkyl group of ˜40; amino group such as diphenylamino group, carbazolyl group; acyl group such as acetyl group, propionyl group, butyryl group; vinyl group, 1-propenyl group, allyl group, butenyl group An alkynyl group having 2 to 20 carbon atoms such as styryl group; an alkynyl group having 2 to 20 carbon atoms such as ethynyl group, 1-propynyl group, propargyl group and phenylacetylin; an alkenyloxy group such as vinyloxy group and allyloxy group; Alkynyloxy groups such as ethynyloxy group and phenylacetyloxy group; phenoxy group, Aryloxy groups such as ftoxy group, biphenyloxy group, pyrenyloxy group; perfluoro groups such as trifluoromethyl group, trifluoromethoxy group, pentafluoroethoxy group, perfluorophenyl group, and further long-chain perfluoro groups; diphenylboryl Groups, dimesitylboryl groups, bis (perfluorophenyl) boryl groups, boryl groups such as 4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl groups; carbonyls such as acetyl groups and benzoyl groups Groups; carbonyloxy groups such as acetoxy group and benzoyloxy group; alkoxycarbonyl groups such as methoxycarbonyl group, ethoxycarbonyl group and phenoxycarbonyl group; sulfinyl groups such as methylsulfinyl group and phenylsulfinyl group; methylsulfonyl group and phenylsulfonyl group Etc. Alkylsulfonyloxy group; arylsulfonyloxy group; phosphino group; phosphinyl groups such as diethylphosphinyl group and diphenylphosphinyl group; trimethylsilyl group, triisopropylsilyl group, dimethyl-tert-butylsilyl group, trimethoxysilyl group Group, silyl group such as triphenylsilyl group; silyloxy group; stannyl group; phenyl group, 2,6-xylyl group, mesityl group, duryl group, biphenyl optionally substituted by halogen atom, alkyl group, alkoxy group, etc. Group, terphenyl group, naphthyl group, anthryl group, pyrenyl group, toluyl group, anisyl group, fluorophenyl group, diphenylaminophenyl group, dimethylaminophenyl group, diethylaminophenyl group, phenanthrenyl group, etc. An aromatic hydrocarbon ring group which may be substituted); a thienyl group, a furyl group, a silacyclopentadienyl group, an oxazolyl group, an oxadiazolyl group, a thiazolyl group, which may be substituted with a halogen atom, an alkyl group or an alkoxy group Group, thiadiazolyl group, acridinyl group, quinolyl group, quinoxaloyl group, phenanthrolyl group, benzothienyl group, benzothiazolyl group, indolyl group, carbazolyl group, pyridyl group, pyrrolyl group, benzoxazolyl group, pyrimidyl group, imidazolyl group, etc. Carboxyl group; Carboxylic acid ester; Epoxy group; Isocyano group; Cyanate group; Isocyanate group; Thiothiocyanate group; Isothiocyanate group; Carbamoyl group; Carbamoyl group, N Such as N- diethylcarbamoyl group N, N- dialkylcarbamoyl group; formyl group; nitroso group; a formyloxy group; and the like.
These groups may be substituted with a halogen atom, an alkyl group, an aryl group, or the like. Furthermore, these groups may be bonded to each other at an arbitrary position to form a ring.

Among these, X ¹ , X ² , X ³ and X ⁴ are each a hydrogen atom; a halogen atom, a carboxyl group, a hydroxy group, a thiol group, an epoxy group, an amino group, an azo group, an acyl group, an allyl group, or a nitro group. , Reactive groups such as alkoxycarbonyl group, formyl group, cyano group, silyl group, stannyl group, boryl group, phosphino group, silyloxy group, arylsulfonyloxy group, alkylsulfonyloxy group; Or a branched alkyl group; a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 8 carbon atoms, an aryl group, an alkenyl group having 2 to 8 carbon atoms A linear or branched alkyl group having 1 to 20 carbon atoms substituted with an alkynyl group having 2 to 8 carbon atoms or the reactive group; Or branched alkoxy group; linear or branched alkyl group having 1 to 8 carbon atoms, linear or branched alkoxy group having 1 to 8 carbon atoms, aryl group, alkenyl having 2 to 8 carbon atoms Group, a C2-C8 alkynyl group or a reactive group substituted with a C1-C20 linear or branched alkoxy group; an aryl group; a C1-C8 linear or branched group A linear alkyl group, a linear or branched alkoxy group having 1 to 8 carbon atoms, an aryl group, a heterocyclic group, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, or the reactive group An aryl group, an oligoaryl group, a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 8 carbon atoms, an aryl group, or a heterocyclic group , Alkenyl having 2 to 8 carbon atoms , An oligoaryl group substituted with an alkynyl group having 2 to 8 carbon atoms or the reactive group; a monovalent heterocyclic group; a linear or branched alkyl group having 1 to 8 carbon atoms; 8 linear or branched alkoxy groups, aryl groups, heterocyclic groups, alkenyl groups having 2 to 8 carbon atoms, alkynyl groups having 2 to 8 carbon atoms, or monovalent complex substituted with the reactive group A cyclic group; a monovalent oligoheterocyclic group; a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 8 carbon atoms, an aryl group, a heterocyclic group, A C2-C8 alkenyl group, a C2-C8 alkynyl group, or a monovalent oligo heterocyclic group substituted with the reactive group; an alkylthio group; an aryloxy group; an arylthio group; an arylalkyl group; an aryl Alkoxy group; arylalkylthio Group; alkenyl group; linear or branched alkyl group having 1 to 8 carbon atoms, linear or branched alkoxy group having 1 to 8 carbon atoms, aryl group, heterocyclic group, and having 2 to 8 carbon atoms An alkenyl group, an alkynyl group substituted with an alkynyl group having 2 to 8 carbon atoms or the reactive group; an alkynyl group; a linear or branched alkyl group having 1 to 8 carbon atoms, a straight chain having 1 to 8 carbon atoms A linear or branched alkoxy group, an aryl group, a heterocyclic group, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, or an alkynyl group substituted with the reactive group; an alkylamino group; C1-C8 linear or branched alkyl group, C1-C8 linear or branched alkoxy group, aryl group, heterocyclic group, C2-C8 alkenyl group, carbon number 2-8 alkynyl groups or the reaction An alkylamino group substituted with a group; an arylamino group; a linear or branched alkyl group having 1 to 8 carbon atoms; a linear or branched alkoxy group having 1 to 8 carbon atoms; an aryl group; A cyclic group, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, or an arylamino group substituted with the reactive group; an arylphosphino group; a linear or branched chain having 1 to 8 carbon atoms A linear alkyl group, a linear or branched alkoxy group having 1 to 8 carbon atoms, an aryl group, a heterocyclic group, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, or the reactive group An aryl phosphino group; an aryl phosphinyl group; a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 8 carbon atoms, an aryl group , Heterocyclic group, charcoal An arylphosphinyl group substituted by an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms or the reactive group; an arylsulfonyl group; a linear or branched alkyl having 1 to 8 carbon atoms Substituted with a group, a linear or branched alkoxy group having 1 to 8 carbon atoms, an aryl group, a heterocyclic group, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, or the reactive group. Any arylsulfonyl group is preferred.

More preferably, a hydrogen atom, a bromine atom, an iodine atom, an amino group, a boryl group, an alkynyl group, an alkenyl group, a formyl group, a silyl group, a stannyl group, a phosphino group, an aryl group substituted with the reactive group, the reaction Oligoaryl group, monovalent heterocyclic group, monovalent heterocyclic group substituted with the reactive group, monovalent oligoheterocyclic group substituted with the reactive group, alkenyl group Or an alkenyl group substituted with the reactive group, an alkynyl group, or an alkynyl group substituted with the reactive group.

Among these, X ¹ and X ² are more preferably functional groups that are resistant to reduction, such as hydrogen atoms, alkyl groups, aryl groups, nitrogen-containing heteroaromatic groups, alkenyl groups, alkoxy groups, aryloxy groups, and silyl groups. Particularly preferred are a hydrogen atom, an aryl group, and a nitrogen-containing heteroaromatic group.
X ³ and X ⁴ are more preferably a functional group resistant to oxidation such as a hydrogen atom, a carbazolyl group, a triphenylamino group, a thienyl group, a furanyl group, an alkyl group, an aryl group, and an indolyl group. Particularly preferred are a hydrogen atom, a carbazolyl group, a triphenylamino group, and a thienyl group.
Thus, assuming that X ¹ and X ² have a functional group resistant to reduction, and X ³ and X ⁴ have a functional group resistant to oxidation, the boron-containing compound as a whole is a compound that is more resistant to reduction and oxidation. It is thought that it becomes.
The above ^X 1 to X ⁴ and, ⁱⁿ the substituents of X 1 to X ^4, as the heterocyclic ring form a heterocyclic group, those represented by the above (4-10) - (4-36) Can be mentioned. As the oligoheterocyclic ring forming the oligoheterocyclic group and the nitrogenous heteroaromatic ring forming the nitrogenous heteroaromatic group, the above-mentioned (4-10) to (4-36) include oligoheterocyclic ring, The thing corresponding to a nitrogen heteroaromatic ring is mentioned.
In the general formula (14), when X ¹ , X ² , X ³ and X ⁴ are monovalent substituents, the bonding position or bonding of X ¹ , X ² , X ³ and X ⁴ with respect to the ring structure The number to do is not particularly limited.

In the general formula (14), ^{Y 1} is ^{n 1} valent connecting group, when ^{n 1} is 2 to 10, as the ^{ring X 1} is bound, in the general formula (14), Y ^{When 1} is a direct bond and n ¹ is 2, it is the same as the ring to which X ¹ is bonded. Among these rings, a benzene ring, a naphthalene ring, and a benzothiophene ring are preferable. More preferably, it is a benzene ring.

In the general formula (14), ^{Y 1} is ^{n 1} valent connecting group, when ^{n 1} is 2 to 10, ring ^{ring X 2} is bonded, it is ^{X 3} is bonded and, As the ring to which X ⁴ is bonded, Y ¹ is a direct bond in the general formula (14), and when n ¹ is 2, a ring to which X ² is bonded, and X ³ is bonded. And the ring mentioned as the ring to which X ⁴ is bonded, and the preferred structure is also the same.

That is, a ^{Y 1} is a direct bond in formula (14), when ^{n 1} is 2, and, ^{Y 1} is ^{n 1} valent linking group, when ^{n 1} is 2 to 10 In any case, the boron-containing compound represented by the general formula (14) is also a boron-containing compound represented by the following general formula (15). It is.

(In the general formula (15), arrows from nitrogen atoms to boron atoms, X ¹ , X ² , X ³ , X ⁴ , n ¹ and Y ¹ are the same as those in the general formula (14).)

As the boron-containing compound used for the second material, a boron-containing compound represented by the following general formula (37) is also preferable.

(In the general formula (37), the dotted arcs are the same or different and represent that a ring structure is formed together with the skeleton part represented by the solid line. The dotted line part in the skeleton part represented by the solid line represents the dotted line. a pair of atoms connected by representing that may be linked by a double bond. arrow from nitrogen atom to boron atom, .R ¹⁸ ~ indicating that the nitrogen atom is coordinated to a boron atom R ^{21 s} are the same or different and each represents a hydrogen atom, a monovalent substituent that serves as a substituent of a ring structure, a divalent group, or a direct bond, R ¹⁸ , R ^19, and R ²¹ are each a dotted line A plurality of R ²⁰ may be bonded to the pyridine ring structure, and the ring to which R ²¹ is bonded is an aromatic heterocyclic ring. there .n ⁶ is an integer from 1 to 4 .n ⁷ is 0 or 1 If n ⁷ is 1, ^{Y 2} are, ^{n 6} divalent linking group, or represents a direct bond, independently and structural parts other than the ^{Y 2} present ^{six n, R 18, R 19,} R 20, ^or, if .n ⁷ indicating that it is bound by any one location in ^{R 21} is 0, ^{n 6} is ^1, at least one of R 18 ^{to R 21} is a substituent of the ring structure And a monovalent substituent.

The boron-containing compound represented by the general formula (37) has a rigid ring structure represented by the general formula (37) in addition to a structure in which a nitrogen atom is coordinated to a boron atom. Therefore, it is a compound having high stability. Further, the boron-containing compound represented by the general formula (37) has good solubility in various solvents, and can easily form a good coating film by coating or the like. Furthermore, since the boron-containing compound of the present invention has a specific ring structure as a substituent on boron, the LUMO energy level is low, and it is considered that the performance as an organic electroluminescence device is excellent.
First, structural parts other than Y ² in the general formula (37) will be described.

In the general formula (37), the dotted circular arc indicates that a ring structure is formed together with the skeleton portion represented by the solid line. The skeleton part represented by the solid line is a part along which a dotted line is written along the solid line. There are three ring structures, and each of the ring structures is referred to herein as a ring to which R ¹⁸ is bonded, a ring to which R ¹⁹ is bonded, and a ring to which R ²¹ is bonded.
In the general formula (37), the meaning of the dotted line portion in the skeleton portion represented by the solid line and the arrow from the nitrogen atom to the boron atom is the same as those in the general formula (14).

In the general formula (37), the ring to which R ²¹ is bonded is an aromatic heterocyclic ring. The aromatic heterocycle has one or more hetero elements in the ring. The hetero element is preferably a nitrogen atom, a sulfur atom, or an oxygen atom, and more preferably a nitrogen atom or a sulfur atom.
The aromatic heterocycle may be a single ring or a condensed ring.
Examples of the aromatic heterocycle include thiophene ring, furan ring, pyrrole ring, benzothiophene ring, benzofuran ring, indole ring, dibenzothiophene ring, dibenzofuran ring, carbazole ring, thiazole ring, benzothiazole ring, oxazole ring, benzol Oxazole ring, imidazole ring, pyrazole ring, benzimidazole ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, quinoline ring, isoquinoline ring, quinoxaline ring, benzothiadiazole ring, phenanthridine ring, oxadiazole ring, thiadiazole ring Is mentioned. These are respectively represented by the above (4-10) to 4-36).

It is one of the preferable modes in the boron-containing compound represented by the general formula (37) that the aromatic heterocycle is a monocycle (monocyclic aromatic heterocycle). The monocyclic aromatic heterocycle is preferably a 5- to 7-membered ring, more preferably a 5-membered ring or a 6-membered ring. Examples of the monocyclic aromatic heterocycle include thiophene ring, furan ring, pyrrole ring, thiazole ring, oxazole ring, imidazole ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, oxadiazole ring, thiadiazole ring. Is mentioned. These are the above formulas (4-10) to (4-12), (4-19), (4-21), (4-23), (4-26) to (4-29), (4 -35) and (4-36). Among these, a thiophene ring, a pyridine ring, and a pyrimidine ring are preferable, and a thiophene ring and a pyridine ring are more preferable.

In the general formula (37), the ring to which R ¹⁸ and R ¹⁹ are bonded may be a ring having no aromaticity, but from the viewpoint of stabilizing the boron-containing compound of the present invention, the ring is aromatic. An aromatic ring such as a hydrocarbon ring or an aromatic heterocyclic ring is preferred. Examples of the aromatic ring include those similar to the ring to which X ¹ is bonded in the case where Y ¹ is a direct bond and n ¹ is 2 in the general formula (14).

In the general formula (37), R ^{18 to} R ²¹ are the same or different and each represents a hydrogen atom, a monovalent substituent that serves as a substituent of a ring structure, a divalent group, or a direct bond. Is not particularly restricted but includes monovalent substituent said, in the general formula (14), include the same groups as specific examples of cases X ^{1, X 2,} X ³ and X ⁴ is a monovalent substituent It is done.

Among the above, R ^{18 to} R ²¹ are preferably the same groups as the preferred groups of X ¹ , X ² , X ³ and X ^{4 in} the general formula (14).
R ^{18 to} R ²¹ are more preferably a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; a silyl group; an alkylamino group; an arylamino group; a boryl group; a stannyl group; 1-8 linear or branched alkyl group; aryl group; oligoaryl group; monovalent heterocyclic group; monovalent oligoheterocyclic group; arylphosphinyl group; arylsulfonyl group .

As the divalent group, for example, a group in which one hydrogen atom is eliminated from a monovalent substituent which is a substituent of the ring structure described above can be used.
R ¹⁸ , R ¹⁹ and R ²¹ may be the same or different and may be bonded to a ring structure forming a dotted arc portion. R ²⁰ may be the same or different and a plurality of R ²⁰ may be bonded to the pyridine ring structure. In addition, the bonding position of the monovalent substituent with respect to the ring structure is not particularly limited.

In the general formula (37), R ²⁰ and R ²¹ are the same or different and each represents a hydrogen atom, a monovalent substituent serving as a substituent of a ring structure, a divalent group, or a direct bond. Among these, at least one of R ²⁰ and R ²¹ is preferably an electron-transporting monovalent substituent that serves as a substituent of the ring structure. By having an electron transporting substituent as R ²⁰ and R ²¹ , the boron-containing compound represented by the general formula (37) becomes a material excellent in electron transporting property.

The electron-transporting monovalent substituent preferably has an aromatic ring. Examples of the electron transporting monovalent substituent having an aromatic ring include, for example, an imidazole ring, a thiazole ring, an oxazole ring, an oxadiazole ring, a triazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, A monovalent group derived from a nitrogen atom-containing heterocycle having a carbon-nitrogen double bond (C = N) in a ring such as a benzimidazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, or a benzothiadiazole ring; An aromatic hydrocarbon ring having no carbon-nitrogen double bond in a ring such as a benzene ring, naphthalene ring, fluorene ring, thiophene ring, benzothiophene ring, carbazole ring or the like having one or more electron-withdrawing substituents; A monovalent group derived from an aromatic heterocycle; dibenzothiophene dioxide ring, dibenzophosphole oxide ring, Lumpur ring and the like.
Examples of the electron withdrawing substituent include —CN, —COR, —COOR, —CHO, —CF ₃ , —SO ₂ Ph, —PO (Ph) _{2, and the} like. Here, R represents a hydrogen atom or a monovalent hydrocarbon group.

The electron-transporting monovalent substituent is, among others, a monovalent group derived from a nitrogen atom-containing heterocycle having a carbon-nitrogen double bond in the ring, and an aromatic having no carbon-nitrogen double bond in the ring. It is preferable to have an aromatic heterocycle such as a monovalent group derived from an aromatic group.
Among these, it is more preferable that the electron-transporting monovalent substituent has a nitrogen atom-containing aromatic heterocycle having a carbon-nitrogen double bond in the ring. The nitrogen atom-containing aromatic heterocycle having a carbon-nitrogen double bond in the ring is preferably a pyridine ring, a pyrimidine ring, or a quinoline ring, and more preferably a pyridine ring.
In addition, it is also preferable that at least one of the R ²⁰ and R ²¹ is a silyl group such as a trimethylsilyl group, a triisopropylsilyl group, a dimethyl-tert-butylsilyl group, a trimethoxysilyl group, or a triphenylsilyl group. It is one of.

Examples of the substituent in R ^{18 to} R ²¹ include the same groups as the substituents in X ¹ , X ² , X ³ and X ⁴ in the general formula (14).
Especially, it is preferable that the substituent in said R < ¹⁸ > -R < ²¹ > is group which has aromatic rings, such as an aromatic-hydrocarbon cyclic group and an aromatic heterocyclic group.
For example, it is preferable that at least one of R ^{18 to} R ²¹ in the general formula (37) is one in which an aromatic ring is further bonded to one of carbon atoms constituting the aromatic heterocyclic ring. Examples of the aromatic ring further bonded to one of the carbon atoms constituting the aromatic heterocyclic ring include an aromatic hydrocarbon ring group and an aromatic heterocyclic group. As the aromatic hydrocarbon ring group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, and a fluorenyl group are preferable. As the aromatic heterocyclic group, a pyridyl group, a quinolyl group, a pyrimidyl group, a thiazole group, and an imidazole group are preferable.
The above-described substituent may be further substituted with a halogen atom, an alkyl group, an aryl group, or the like, and is preferably substituted with, for example, a linear or branched alkyl group having 1 to 8 carbon atoms. . Further, these substituents may be bonded to each other at any position to form a ring.

Hereinafter, Y ² , n ⁶ , and n ⁷ in the general formula (37) will be described.
N ⁶ is an integer of 1 to 4. n ⁷ is 0 or 1. If n ⁷ is 1, ^{Y 2} are, ^{n 6} divalent linking group, or represents a direct bond, independently and structural parts other than the ^{Y 2} present ^{six n, R 18, R 19,} R 20, or represents be attached at any one location of R ^21.

In the general formula (37), when ^{n 6} is 1, ^{n 7} is 0, the compound consisting of structural portions other than the ^{Y 2} in the general formula (37). In this case, at least one of R ^{18 to} R ²¹ represents a monovalent substituent that serves as a substituent of the ring structure. Among them, it is preferable that at least one of R ²⁰ and R ²¹ represents an electron-transporting monovalent substituent that serves as a substituent of the ring structure.
In the general formula (37), when n ⁶ is 2, there are two structural parts other than Y ² in the general formula (37). Here, when Y ² is a divalent linking group, so that the two existing Y ² other structural part of is bonded through Y ² represents a divalent linking group. When Y ² is a direct bond, two existing structural parts other than Y ² are directly bonded.
In the compound represented by the general formula (37), when n ⁶ is 3 or more, Y ² is an n ^6- valent linking group, and the structural portion other than Y ² in the general formula (37) is n ^6. And they are bonded through Y ² which is a linking group.

N ⁶ in the general formula (37) is preferably 1 to 3, more preferably 1 to 2. That is, the boron-containing compound of the present invention is more preferably a monomer or a dimer.

In addition, when Y ² is an n ^6- valent linking group, Y ² is any one of R ¹⁸ , R ¹⁹ , R ²⁰ , or R ²¹ independently of the n ⁶ structural portions other than Y ² . Although attached at one point, which is the binding site of the Y ² structural portions other than the Y ² is an independently to each structural part other than the Y ² present ^six n, all had the same site It may mean that a part may be the same part or all may be different parts. The bonding position is not particularly limited, but it is preferable that all the structural parts other than n ^{6 that} are present except Y ² are bonded by R ²⁰ or R ²¹ .
In addition, the structures of the structural parts other than n ^{6 which} are other than Y ² may all be the same, a part of them may be the same, or all may be different.

The general formula Y ² is in (37), when it is n ⁶ divalent linking group, examples of the linking group, for example, have a substituent which may linear, branched or cyclic hydrocarbon radical , A group containing a hetero element which may have a substituent, an aromatic hydrocarbon ring group which may have a substituent, and an aromatic heterocyclic group which may have a substituent. Among these, a group having an aromatic ring such as an aromatic hydrocarbon ring group which may have a substituent and an aromatic heterocyclic group which may have a substituent is preferable. That is, in the general formula (37), Y ² is also a group having an aromatic ring, which is one of the preferred embodiments of the present invention.
Furthermore, Y ² may be a linking group having a structure in which a plurality of the linking groups described above are combined.

The chain, branched chain or cyclic hydrocarbon group is preferably a group represented by any one of the above formulas (2-1) to (2-8). Among these, the above formulas (2-1) and (2-7) are more preferable.
The group containing a hetero element is preferably a group represented by any one of the above formulas (2-9) to (2-13). Among these, the above formulas (2-12) and (2-13) are more preferable.

The aromatic hydrocarbon ring group is preferably a group represented by any one of the above formulas (2-14) to (2-20). Among these, the above formulas (2-14), (2-19), and (2-20) are more preferable.

The aromatic heterocyclic group is preferably a group represented by any one of the above formulas (2-21) to (2-33). Among these, the above formulas (2-24) and (2-32) are more preferable.

Examples of the substituent of the chain, branched chain, or cyclic hydrocarbon group, a group containing a hetero element, an aromatic hydrocarbon ring group, and an aromatic heterocyclic group include the R in the general formula (37) described above. The same thing as the substituent which ¹⁸ and R <^19> , R <^20> and R < ²¹ > may have is mentioned.
Among these, as a substituent which the chain, branched chain, or cyclic hydrocarbon group in Y ² , a group containing a hetero element, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group has, a halogen atom, a carbon number A linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkoxy group having 1 to 20 carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and a diarylamino group are preferable. More preferred are an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and a diarylamino group.
When the chain, branched chain or cyclic hydrocarbon group in Y ² above, a group containing a hetero element, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group has a substituent, the position and number of the substituent bonded Is not particularly limited.

The boron-containing compound represented by the general formula (14) and the boron-containing compound represented by the general formula (37) can be synthesized by using various commonly used reactions such as the Suzuki coupling reaction. Further, it can be synthesized by the method described in Journal of the American Chemical Society, 2009, Vol. 131, No. 40, pages 14549-14559.

The following reaction formulas (I) to (III) are examples of the synthesis method of the boron-containing compound represented by the general formula (14) and the boron-containing compound represented by the general formula (37). An example of a method for synthesizing the boron-containing compound represented by 14-1) and the boron-containing compound represented by (14-2) is shown. In addition, the manufacturing method of the boron containing compound represented by the said General formula (14) and the boron containing compound represented by the said General formula (37) is not restrict | limited to this. In the following reaction formulas (I) to (III), THF is tetrahydrofuran. In the following reaction formula (III), n-BuLi is n-butyllithium.

The following reaction formula (I) is a boron-containing compound represented by the above general formula (14), where Y ¹ is a direct bond and n ¹ is 2, and in the above general formula (37) The boron-containing compound represented by the general formula (14-1) corresponding to the case where Y ² is a direct bond, n ⁶ is 2, and n ⁷ is 1. A synthesis example is shown.
The following reaction formula (II) is a boron-containing compound represented by the above general formula (14), Y ¹ is n ¹ valent connecting group, when n ¹ is 2, and the general formula A boron-containing compound represented by (37), wherein Y ² is a divalent linking group, n ⁶ is 2, and n ⁷ is 1, 1 represents a synthesis example of a boron-containing compound (2,7-bis (3-dibenzoborolyl-4-pyridylphenyl) -9,9′-spirofluorene) represented.

In addition, in the following reaction formulas (I) to (III), 2- (dibenzoborolylphenyl) -5-bromopyridine represented by the general formula (a) used as a raw material is, for example, Journal of Organic Chemistry. (Journal of Organic Chemistry), 2010, Vol. 75, No. 24, pages 8709-8712. Further, in the following reaction formula (I), the compound represented by the general formula (b) used as a raw material is based on 2- (dibenzoborolylphenyl) -5-bromopyridine represented by the general formula (a). Can be synthesized by a boronation reaction represented by the following reaction formula (III).

The boron-containing compound represented by the general formula (14) is particularly preferably a boron-containing compound represented by the general formula (14-1) or (14-2), and the general formula (14-2) Most preferred is a boron-containing compound represented by:

Further, the boron-containing compound represented by the general formula (37) is represented by the following formula (38-1) or the following formula (38-2);

(In the formula, an arrow from a nitrogen atom to a boron atom, R ¹⁸ , R ¹⁹ , R ²⁰ and R ²¹ are the same as those in the general formula (37)). It is one of the preferred embodiments of the invention.

As the boron-containing compound used for the second material, a boron-containing compound represented by the following general formula (39) is also preferable.

(In the general formula (39), a dotted circular arc represents that a ring structure is formed together with a skeleton part represented by a boron atom or a solid line, and the ring structure is the same or different and is composed of one ring. The dotted structure in the skeleton represented by the solid line may be a double pair of atoms connected by a dotted line. An arrow from a nitrogen atom to a boron atom indicates that the nitrogen atom is coordinated to the boron atom, and Q ⁷ is a link in the skeleton part represented by a solid line. R ²² and R ²³ are the same or different and may be substituted with a hydrogen atom or a ring structure, at least part of which forms a ring structure together with a dotted arc portion. Monovalent substituent, divalent group, or direct bond as a base And a plurality bonded good .R ²⁴ and R ²⁵ even if the ring structure to form an arc portion of the dotted line, the same or different and each represents a hydrogen atom, a monovalent substituent, a divalent group or a direct R ²⁴ and R ²⁵ are bonded to each other and do not form a ring structure with a skeleton represented by a double line, and n ⁸ is an integer of 1 to 4. n ⁹ is If .n ⁹ is 1 is 0 or 1, ^{Y 3} is, ^{n 8} divalent linking group, or represents a direct bond, independently and structural parts other than ^{Y 3} present ^{eight n, R 22,} It represents bonding at any one of R ²³ , R ²⁴ , or R ^25. )

The boron-containing compound represented by the general formula (39) has a rigid ring structure represented by the general formula (39) in addition to a structure in which a nitrogen atom is coordinated to a boron atom. Therefore, it is a compound having high stability. In addition, the boron-containing compound represented by the general formula (39) has good solubility in various solvents and can easily form a good coating film by coating or the like. Furthermore, since the boron-containing compound of the present invention has a specific ring structure as a substituent on boron, the LUMO energy level is low, and it is considered that the performance as an organic electroluminescence device is excellent.
First, structural parts other than Y ³ in the general formula (39) will be described.

In the general formula (39), the meaning of the dotted arc in the dotted arc, the dotted portion in the skeleton represented by the solid line, and the arrow from the nitrogen atom to the boron atom is the same as that in the general formula (37). In the general formula (39), there are two ring structures formed by a dotted arc and a skeleton portion represented by a boron atom or a solid line, and each of the ring structures is bonded to R ^{22 in} this specification. Ring, and the ring to which R ²³ is bonded.

In the above general formula (39), Q ⁷ is a linking group in the skeleton portion represented by a solid line, and at least a part thereof forms a ring structure with a dotted arc portion, and has a substituent. You may do it. This represents that Q ⁷ is incorporated as part of the ring structure.
Examples of Q ⁷ in the above formula (39) include the structures represented by the above formulas (3-1) to (3-8). Among them, the formula (3-1), the formula (3-7), Any of formula (3-8) is preferable. More preferably, it is Formula (3-1). That is, it is also one of the preferred embodiments of the present invention that Q ⁷ represents a linking group having 1 carbon atom.

In the general formula (39), the ring to which R ²² is bonded may be a ring having no aromaticity, but is preferably an aromatic ring. In addition, the ring to which R ²² is bonded may be a monocyclic structure composed of one ring, but is preferably a condensed ring structure composed of a plurality of rings. As in the boron-containing compound represented by (40), a condensed ring structure composed of at least three rings is more preferable. Furthermore, the ring to which R ²² is bonded may or may not have a hetero element other than a boron atom in the ring.

In the general formula (39), the ring to which R ²³ is bonded may be a nitrogen-containing heterocycle having no aromaticity. However, the boron-containing compound of the present invention is stabilized, and an organic electroluminescent element material is obtained. From the viewpoint of exhibiting excellent performance, it is preferably a nitrogen-containing aromatic heterocyclic ring. Examples of the nitrogen-containing aromatic heterocycle include imidazole ring, benzimidazole ring, pyridine ring, pyridazine ring, pyrazine ring, pyrimidine ring, quinoline ring, isoquinoline ring, phenanthridine ring, quinoxaline ring, benzothiadiazole ring, and thiazole. A ring, a benzothiazole ring, an oxazole ring, a benzoxazole ring, an oxadiazole ring, and a thiadiazole ring. These are respectively represented by the above formulas (5-1) to (5-17). Incidentally, symbol * in the formula (5-1) to ^(5-17), the carbon atom bonded to the ^{R 24} is represents the binding to any one of the carbon atoms attached marked *. In addition, the rings represented by the formulas (5-1) to (5-17) may be condensed with other ring structures at positions excluding the carbon atoms marked with *. Among these, a nitrogen-containing heteroaromatic ring containing a 6-membered ring such as a pyridine ring, a pyrazine ring, a pyrimidine ring, a quinoline ring, and a phenanthridine ring is preferable. The ring to which R ²³ is bonded is more preferably a pyridine ring, a pyrazine ring, a pyrimidine ring or a quinoline ring, and more preferably a pyridine ring.

In the general formula (39), R ²² and R ²³ are the same or different and each represents a hydrogen atom, a monovalent substituent that serves as a substituent of a ring structure, a divalent group, or a direct bond. R ²⁴ and R ²⁵ are the same or different and each represents a hydrogen atom, a monovalent substituent, a divalent group, or a direct bond. Monovalent substituent comprising a substituent of the ring structure in the ^{R 22,} R ^23, is not particularly restricted but includes monovalent substituent in ^{R 24,} R ^25, in formula ^{(14), X 1, X} 2 , X ³ and X ⁴ are the same as the specific examples in the case of a monovalent substituent that is a substituent of the ring structure, and among them, preferred substituents are also X ¹ , X ² , X ³ and The same as the preferable substituent of X ⁴ .

In the general formula (39), R ²⁴ and R ²⁵ are not bonded to each other to form a ring structure together with the skeleton portion represented by a double line. The ring structure includes those having a coordination bond in the skeleton portion.
As R ²⁴ , the atom directly bonded to the carbon atom of the skeleton represented by the double line in the general formula (39) is more preferably an atom other than an oxygen atom.
R ²² , R ²³ , R ²⁴ , and R ²⁵ are particularly preferably a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; a silyl group; an alkylamino group; an arylamino group; A stanyl group; a linear or branched alkyl group having 1 to 8 carbon atoms; an aryl group; an oligoaryl group; a monovalent heterocyclic group; a monovalent oligoheterocyclic group; an arylphosphinyl group; One of the groups.

As the divalent group in R ²² , R ²³ , R ²⁴ , and R ²⁵ , for example, a group in which one hydrogen atom is eliminated from the above-described monovalent substituent can be used.
R ²² and R ²³ may be the same or different, and a plurality of R ²² and R ²³ may be bonded to a ring structure forming a dotted arc portion. Further, the bonding position of the monovalent substituent with respect to the ring structure is not particularly limited.

In the general formula (39), it is preferable that at least one of R ²³ , R ²⁴ , and R ²⁵ represents an electron-transporting monovalent substituent that serves as a substituent of the ring structure. By having an electron transporting substituent as R ²³ , R ²⁴ , and R ²⁵ , the boron-containing compound of the present invention is a material having excellent electron transporting properties. Among these, it is more preferable that R ²⁵ has an electron transporting substituent.

The electron-transporting monovalent substituent preferably has an aromatic ring. For example, R ²⁵ preferably represents a monovalent substituent having an aromatic ring. Examples of the monovalent substituent having an aromatic ring include imidazole ring, thiazole ring, oxazole ring, oxadiazole ring, triazole ring, pyrazole ring, pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, benzimidazole ring, A monovalent group derived from a nitrogen atom-containing heterocycle having a carbon-nitrogen double bond (C = N) in a ring such as a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, or a benzothiadiazole ring; Aromatic hydrocarbon ring or aromatic heterocycle having no carbon-nitrogen double bond in a ring such as a benzene ring, naphthalene ring, fluorene ring, thiophene ring, benzothiophene ring, carbazole ring or the like having an electron withdrawing substituent Monovalent group derived from: dibenzothiophene dioxide ring, dibenzophosphole oxide ring, diarylphos In'okishido group, silol ring and the like.
Examples of the electron withdrawing substituent include —CN, —COR, —COOR, —CHO, —CF ₃ , —SO ₂ Ph, —PO (Ph) _{2, and the} like. Here, R represents a hydrogen atom or a monovalent hydrocarbon group.

The electron-transporting monovalent substituent is, among others, a monovalent group derived from a nitrogen atom-containing heterocycle having a carbon-nitrogen double bond in the ring, and an aromatic having no carbon-nitrogen double bond in the ring. It is preferable to have an aromatic heterocycle such as a monovalent group derived from an aromatic group.
Among these, it is more preferable that the electron-transporting monovalent substituent has a nitrogen atom-containing aromatic heterocycle having a carbon-nitrogen double bond in the ring. The nitrogen atom-containing aromatic heterocycle having a carbon-nitrogen double bond in the ring is preferably a pyridine ring, a pyrimidine ring, or a quinoline ring, and more preferably a pyridine ring.
From the viewpoint of increasing the electron mobility of the boron-containing compound of the present invention, in the general formula (39), the ring to which R ²³ is bonded is a nitrogen-containing aromatic heterocycle, and R ²⁵ is an aromatic ring. It is particularly preferable to represent a monovalent substituent having the same. Among them, it is most preferable that the ring to which R ²³ is bonded is a pyridine ring, and R ²⁵ represents a benzene ring.

Examples of the substituent in R ²² , R ²³ , R ²⁴ and R ²⁵ include the same groups as the substituents in X ¹ , X ² , X ³ and X ⁴ in the general formula (14).
Especially, it is preferable that the substituent in said R < ²³ >, R <^24> , R < ²⁵ > is group which has aromatic rings, such as an aromatic hydrocarbon ring group and an aromatic heterocyclic group.
For example, it is preferable that at least one of R ²³ , R ²⁴ and R ²⁵ in the general formula (39) is one in which an aromatic ring is further bonded to one of carbon atoms constituting the aromatic heterocyclic ring. Examples of the aromatic ring further bonded to one of the carbon atoms constituting the aromatic heterocyclic ring include an aromatic hydrocarbon ring group and an aromatic heterocyclic group. As the aromatic hydrocarbon ring group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, and a fluorenyl group are preferable. As the aromatic heterocyclic group, a pyridyl group, a pyrrolyl group, a quinolyl group, a pyrimidyl group, a thiazole group, and an imidazole group are preferable. Specifically, at least one of R ²³ , R ²⁴ and R ²⁵ is bipyridine, which is a preferred example from the viewpoint of improving the electron injection property.
The above-described substituent may be further substituted with a halogen atom, an alkyl group, an aryl group, or the like, and is preferably substituted with, for example, a linear or branched alkyl group having 1 to 8 carbon atoms. . Further, these substituents may be bonded to each other at any position to form a ring.

Hereinafter, Y ³ , n ⁸ , and n ⁹ in the general formula (39) will be described.
It said ^{n 8} is an integer of 1 to 4. n ⁹ is 0 or 1. If n ⁹ is 1, ^{Y 3} is, ^{n 8} divalent linking group, or represents a direct bond, independently and structural parts other than ^{Y 3} present ^{eight n, R 22, R 23,} R 24, or represents be attached at any one location of R ^25.

In the general formula (39), when n ⁸ is 1, n ⁹ is 0, and the compound is composed of only a structural portion other than Y ³ in the general formula (39).
From the viewpoint of improving the thermal stability of the boron-containing compound of the present invention, in the general formula (39), n ⁸ is an integer of 2 to 4, and n ⁹ is preferably 1.
In the general formula (39), when n ⁸ is 2, there are two structural portions other than Y ³ in the general formula (39). Here, when Y ³ is a divalent linking group, so that the two existing Y ³ than the structural portion of the is bonded through Y ³ represents a divalent linking group. When Y ³ is a direct bond, two existing structural parts other than Y ³ are directly bonded.
In the compound represented by the general formula (39), when ^{n 8} is 3 or more, ^{Y 3} is ^{n 8} divalent linking group, structural parts other than ^{Y 3} in the general formula (39) ^{n 8} And they are bonded via Y ³ which is a linking group.

Note that when ^{Y 3} is ^{n 8} divalent linking group, ^{Y 3} are each independently a structural part other than ^{Y 3} present ^{eight n, R 22, R 23,} R 24, ^or one of ^{R 25} Although it attached at one point, which is the binding site of the Y ³ structural portions other than Y ³ is a independently each structural part other than Y ³ present ^eight n, all had the same site It may mean that a part may be the same part or all may be different parts. The bonding position is not particularly limited, but it is preferable that all of the structural parts other than n ⁸ existing except Y ³ are bonded by R ²³ , R ²⁴ , or R ²⁵ .
Further, the structures of the structural parts other than n ^{8 that} are other than Y ³ may all be the same, a part of them may be the same, or all may be different.

Y ³ in the general formula (39), when it is n ⁸ divalent linking group, examples of the linking group, for example, have a substituent which may linear, branched or cyclic hydrocarbon radical , A group containing a hetero element which may have a substituent, an aromatic hydrocarbon ring group which may have a substituent, and an aromatic heterocyclic group which may have a substituent. Among these, a group having an aromatic ring such as an aromatic hydrocarbon ring group which may have a substituent and an aromatic heterocyclic group which may have a substituent is preferable. That, Y ³ in the general formula (39), it is also one of the preferred embodiments of the present invention represents a n ⁸ divalent linking group having an aromatic ring.
Further, Y ³ may be a linking group having a structure in which a plurality of the linking groups described above are combined.

The chain, branched chain or cyclic hydrocarbon group is preferably a group represented by any one of the formulas (2-1) to (2-8) described above. Among these, formulas (2-1) and (2-7) are more preferable.
The group containing a hetero element is preferably a group represented by any one of the above-described formulas (2-9) to (2-13). Among these, the formulas (2-12) and (2-13) are more preferable.

The aromatic hydrocarbon ring group is preferably a group represented by any of the formulas (2-14) to (2-20) described above. Among these, the formulas (2-14), (2-19), and (2-20) are more preferable.

The aromatic heterocyclic group is preferably a group represented by any of the formulas (2-21) to (2-33) described above. Among these, the formulas (2-24) and (2-32) are more preferable.

Examples of the substituent of the chain, branched chain, or cyclic hydrocarbon group, a group containing a hetero element, an aromatic hydrocarbon ring group, and an aromatic heterocyclic group include the R in the general formula (39) described above. ²³ , R ²⁴ and R ²⁵ are the same as the substituents which may be present.
Among these, as the substituent of the chain, branched chain or cyclic hydrocarbon group in Y ³ , a group containing a hetero element, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group, a halogen atom, a carbon number A linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkoxy group having 1 to 20 carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and a diarylamino group are preferable. More preferred are an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and a diarylamino group.
When the chain, branched chain or cyclic hydrocarbon group in Y ³ above, a group containing a hetero element, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group has a substituent, the position and number of the substituent bonded Is not particularly limited.

As described above, in the general formula (39), the ring to which R ²² is bonded is more preferably a condensed ring structure composed of at least three rings. That is, the boron-containing compound of the present invention is represented by the following general formula (40);

(In the formula, dotted arcs are the same or different and represent that a ring structure is formed together with the skeleton represented by the solid line. Q ⁸ is a linking group in the skeleton represented by the solid line; A ring structure may be formed at least partly with the dotted arc portion, and may have a substituent, R ²²¹ and R ²²² may be the same or different and are a hydrogen atom or a substituent of the ring structure. valent substituent, a divalent group, or represents a direct bond, if multiple binding and optionally .n ⁹ in the ring structure to form an arc portion of the dotted line is 1, Y ³ is, n ^8-valent linking group, or represents a direct bond, respectively and structural parts other than ^{Y 3} present ^{eight n independently, R 221, R 222, R} 23, R 24, ^or attached at any one point of ^{R 25} Dotted line in the skeleton represented by the solid line Arrow from nitrogen atoms to boron ^{atoms, Q 7, R 23, R} 24, R 25, n 8 and,, ^{n 9} is the same as in the general formula (39).) It is more preferably represented by.

In the general formula (40), the dotted arc indicates that a ring structure is formed together with the skeleton portion represented by the solid line. The skeleton part represented by the solid line is a part along which a dotted line is written along the solid line. There are three ring structures, and each of the ring structures is referred to as a ring to which R ²²¹ is bonded, a ring to which R ²²² is bonded, and a ring to which R ²³ is bonded.
In the general formula (40), the dotted line portion in the skeleton portion represented by the solid line represents that a pair of atoms connected by the dotted line may be connected by a double bond.

In the general formula (40), the ring to which R ²²¹ and R ²²² are bonded may be a ring having no aromaticity, but from the viewpoint of stabilizing the boron-containing compound of the present invention, the ring is aromatic. An aromatic ring such as a hydrocarbon ring or an aromatic heterocyclic ring is preferable. Examples of the aromatic ring include a benzene ring, naphthalene ring, anthracene ring, tetracene ring, pentacene ring, triphenylene ring, pyrene ring, fluorene ring, indene ring, thiophene ring, furan ring, pyrrole ring, benzothiophene ring, and benzofuran ring. , Indole ring, dibenzothiophene ring, dibenzofuran ring, carbazole ring, thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, imidazole ring, pyrazole ring, benzimidazole ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, Examples include a quinoline ring, an isoquinoline ring, a quinoxaline ring, a benzothiadiazole ring, a phenanthridine ring, an oxadiazole ring, and a thiadiazole ring. Ru Among these, a benzene ring, a naphthalene ring, and a benzothiophene ring are preferable. More preferably, it is a benzene ring.

In the general formula (40), the ring R ²³ is attached is the same as the ring R ²³ of the general formula described above (39) is attached.
In the general formula (40), R ²²¹ and R ²²² are the same as R ^{22 in the} general formula (39) described above.
In the above general formula (40), Q ⁸ is the same as Q ⁷ in the above general formula (39). For example, it is preferable that at least one of Q ⁷ and Q ⁸ represents a linking group having 1 carbon atom.

In the general formula (40), when Y ³ is an n ⁸ valent linking group, Y ³ is independently of R ⁸ other structural portion other than Y ³ , R ²²¹ , R ²²² , R ^23. , ^{R 24, or,} although attached at any one point of ^{R 25,} which is the binding site of the ^{Y 3} structural portions other than ^{Y 3} are each structural part other than ^{Y 3} present ^{eight n} It is independent, and all may be the same site | part, a part may be the same site | part, and all may be a different site | part. The bonding position is not particularly limited, but it is preferable that all of the structural parts other than n ⁸ existing except Y ³ are bonded by R ²³ , R ²⁴ , or R ²⁵ .
Further, the structures of the structural parts other than n ^{8 that} are other than Y ³ may all be the same, a part of them may be the same, or all may be different.

The boron-containing compound of the present invention is represented by the following formulas (41-1) to (41-3);

(In the formula, an arrow from a nitrogen atom to a boron atom, a dotted arc, a dotted line portion in a skeleton represented by a solid line, Q ⁷ , R ²²¹ , R ²²² , R ²³ , R ²⁴ , R ²⁵ , and Y ³ Is a boron-containing compound represented by any one of the general formula (40), is also one preferred embodiment of the present invention. Thereby, thermal stability improves. Among these, the boron-containing compound of the present invention is more preferably represented by the above formula (41-2).

The boron-containing compound represented by the general formula (39) can be produced, for example, based on the method described in Japanese Patent No. 5553149. That is, as shown in the following reaction formula, an alkyne compound represented by formula (I) is used as a starting material, and this is reacted with a boron halide compound BX ₃ to obtain an alkene compound represented by formula (II). Further, this is reacted with a magnesium element-containing compound represented by formula (i) or formula (ia) to produce a compound represented by formula (III) or formula (IIIa). The cyclization reaction uses the same method as described in Japanese Patent Application No. 2013-202578. The halogen atom X contained in the compound represented by the formula (III) or the formula (IIIa) is subjected to halogen-lithium exchange with a lithiating agent such as t-BuLi, and reacted with an electrophile to thereby form a hydrogen atom or 1 Substituted with a valent substituent, or substituted with a hydrogen atom or a monovalent substituent as described in Japanese Patent No. 5553149, and represented by the general formula (39) or the general formula (40). Boron-containing compounds can be obtained. Moreover, in the following reaction formula, X is the same or different and represents an iodine atom, a bromine atom, or a chlorine atom. The dotted arc is the same as the general formula (39) described above for compounds other than the magnesium element-containing compound represented by the formula (i), and the formula (i) III) Corresponds to the structure part of the dotted arc that forms a ring structure with the boron atom of the compound represented by formula (III), and the two MgXs at the ends bonded to the structure part are bonded to each other to form a ring. It does not form a structure and replaces the boron atom of the compound represented by formula (III). Further, the dotted line portion in the skeleton portion represented by the solid line, the arrow from the nitrogen atom to the boron atom, Q ⁷ , R ²² , R ²³ , R ²⁴ , R ²⁵ , Y ³ , n ⁸ , and n ⁹ are as described above. It is the same as general formula (39). Q ⁸ , R ²²¹ and R ²²² are the same as those in the general formula (40) described above.

The boron-containing compound represented by the general formula (39) is a compound represented by the formula (III) or the formula (IIIa) described above, and the monomer (n ⁸ is 1, n ⁹ is 0). It is also possible to obtain a monomer by dimerization. For example, the boron-containing compound represented by the general formula (39) can be obtained by the following reaction formula.

Moreover, as a boron containing compound used for the said 2nd material, the boron containing compound represented by following General formula (16) is also preferable.

(In the general formula (16), a dotted circular arc indicates that a ring structure is formed together with a skeleton portion represented by a solid line. A dotted line portion in the skeleton portion represented by a solid line is a pair connected by a dotted line. The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ³ and Q ⁴ are the same. or different, is a linking group in the skeleton moiety represented by the solid line, forms a ring structure at least partially with a circular arc portion of the dotted line, which may have a substituent .X ^5, X ⁶ is X ⁷ and X ⁸ are the same or different and each represents a hydrogen atom or a monovalent substituent serving as a substituent of the ring structure, and X ⁷ and X ⁸ are the same or different and represent an electron transporting property 1 serving as a substituent of the ring structure. represents the valence of the substituent ^{.X 5, X 6,} X ⁷ and ^{X 8} are each point The ring structure to form an arc portion may be a plurality bonds.)

In the general formula (16), the dotted arc represents a skeleton part represented by a solid line, that is, a part of the skeleton part that connects the boron atom and Q ³ , or a skeleton part that connects the boron atom, Q ⁴ and the nitrogen atom. A ring structure is formed together with a part of This is because the compound represented by the general formula (16) has at least four ring structures in the structure, and in the general formula (16), a skeleton part connecting the boron atom and Q ³ and the boron atom and Q ⁴ This represents that a skeleton portion connecting the nitrogen atom is included as a part of the ring structure.

In the general formula (16), the skeleton part represented by a solid line, that is, the skeleton part that connects the boron atom and Q ³ , and the dotted line part in the skeleton part that connects the boron atom, Q ^4, and the nitrogen atom, It represents that a pair of atoms connected by a dotted line in the skeleton part may be connected by a double bond.

In the general formula (16), an arrow from a nitrogen atom to a boron atom represents that the nitrogen atom is coordinated to the boron atom. Here, coordinating means that the nitrogen atom acts on the boron atom in the same manner as the ligand and chemically affects it.

In the general formula (16), Q ³ and Q ⁴ are the same or different and are a linking group in a skeleton part represented by a solid line, and at least a part forms a ring structure together with a dotted arc part And may have a substituent. This indicates that Q ³ and Q ⁴ are each incorporated as part of the ring structure.

Examples of Q ³ and Q ⁴ in the general formula (16) include structures represented by the above formulas (3-1) to (3-8). The general formula (3-2) has a structure in which two hydrogen atoms are bonded to a carbon atom and three atoms are further bonded. However, the three atoms bonded to the carbon atom other than the hydrogen atom are: All are atoms other than a hydrogen atom. Among the general formulas (3-1) to (3-8), any of (3-1), (3-7), and (3-8) is preferable. More preferably, it is (3-1). That is, it is also one of the preferred embodiments of the present invention that Q ³ and Q ⁴ are the same or different and represent a linking group having 1 carbon atom.

In the general formula (16), as the ring to which X ^{5 to} X ⁷ are bonded, in the general formula (14), when Y ¹ is a direct bond and n ¹ is 2, X ¹ is The same ring as the specific example of the ring which has couple | bonded is mentioned. Among these, a benzene ring, a naphthalene ring, a thiophene ring, and a benzothiophene ring are preferable. More preferred are a benzene ring and a thiophene ring.

In the general formula (16), as the ring to which X ⁸ is bonded, when Y ¹ is a direct bond and n ¹ is 2 in the general formula (14), X ² is bonded. The same ring as the specific example of the ring which is mentioned is mentioned, The preferable ring structure in it is also the same. The above formula (5-1) to (5-17) in the * mark constitutes a ^{ring X 7} is attached and the boron atom to ^{Q 4} and the nitrogen atom in the general formula (16) The carbon atom which comprises the skeleton part which connects is couple | bonded with any one of the carbon atoms marked with *. Further, it may be condensed with another ring structure at a position excluding the carbon atom marked with *.

That is, it is also one preferred embodiment of the present invention that the boron-containing compound represented by the general formula (16) is a boron-containing compound represented by the following general formula (17).

(In the general formula (17), arrows from nitrogen atoms to boron atoms, X ⁵ , X ⁶ , X ⁷ and X ⁸ are the same as those in the general formula (16).)

In the boron-containing compound represented by the general formula (17), the ring to which X ⁵ , X ⁶ , X ⁷ , and X ⁸ are bonded is only a carbon atom except for the nitrogen atom coordinated to the boron atom. Therefore, as compared with a compound containing a heteroatom such as S in the ring, the orbital spread is reduced, and in general, the energy gap of HOMO-LUMO is kept wide. Therefore, for example, it can be suitably used as an electron injection layer of an organic electroluminescence device.

In the general formula (16), X ⁵ and X ⁶ are the same or different and each represents a hydrogen atom or a monovalent substituent serving as a substituent of a ring structure. Is not particularly restricted but includes monovalent substituent said, are the same as specific examples of the monovalent substituent of X ^1, X ^2, X ³ and X ⁴ in the general formula (14), with a more preferred The preferred substituents are the same except that the substituent includes an oligoaryl group, a monovalent heterocyclic group, and a monovalent oligoheterocyclic group.
In the above general formula ^(16), X ^5, if X 6, ^{X 7} and ^{X 8} is a monovalent substituent, the bonding position and coupling of ^{X 5,} X 6, ^{X 7} and ^{X 8} against the ring structure The number to do is not particularly limited.

In the general formula (16), X ⁷ and X ⁸ are the same or different and represent an electron-transporting monovalent substituent that serves as a substituent of the ring structure. By having an electron transporting substituent as X ⁷ and X ⁸ , the boron-containing compound represented by the general formula (16) becomes a material excellent in electron transporting property.
Examples of the electron transporting monovalent substituent include imidazole ring, thiazole ring, oxazole ring, oxadiazole ring, triazole ring, pyrazole ring, pyridine ring, pyrazine ring, triazine ring, benzimidazole ring, benzothiazole. A monovalent group derived from a nitrogen atom-containing heterocycle having a carbon-nitrogen double bond (C = N) in the ring, quinoline ring, isoquinoline ring, quinoxaline ring, benzothiadiazole ring, etc .; one or more electron withdrawing 1 derived from an aromatic hydrocarbon ring or aromatic heterocycle having no carbon-nitrogen double bond in a ring such as a benzene ring, naphthalene ring, fluorene ring, thiophene ring, benzothiophene ring, carbazole ring, etc. A valent group; a dibenzothiophene dioxide ring, a dibenzophosphole oxide ring, a silole ring and the like.

Examples of the electron withdrawing substituent include —CN, —COR, —COOR, —CHO, —CF ₃ , —SO ₂ Ph, —PO (Ph) _{2, and the} like. Here, R represents a hydrogen atom or a monovalent hydrocarbon group.
Among these, the electron-transporting monovalent substituent is preferably a group derived from a nitrogen atom-containing heterocycle having a carbon-nitrogen double bond (C═N) in the ring.
The electron-transporting monovalent substituent is more preferably any of monovalent groups derived from a heteroaromatic ring compound having a carbon-nitrogen double bond in the ring.

The substituent in X ⁵ , X ⁶ , X ⁷ and X ⁸ is the same as the substituent in X ¹ , X ² , X ³ and X ⁴ in the general formula (14).

The boron-containing compound represented by the general formula (16) can be synthesized by, for example, a synthesis method that performs the following first step and second step. In the following reaction formula, Z ¹ represents a bromine atom or an iodine atom, and Z ² represents a chlorine atom, a bromine atom or an iodine atom.

In the method for synthesizing the boron-containing compound represented by the general formula (16), the solvent used in the first step is not particularly limited, but hexane, heptane, benzene, toluene, diethyl ether, diisopropyl ether, dibutyl ether, cyclopentylmethyl. An ether etc. are mentioned, These 1 type (s) or 2 or more types can be used.
In addition, the 1st process in the synthesis | combining method of the boron containing compound represented by the said General formula (16) can be performed with reference to description of Unexamined-Japanese-Patent No. 2011-184430.

The temperature at which the reaction in the second step is performed is preferably 0 ° C. to 40 ° C., and the reaction may be performed under any of normal pressure, reduced pressure, and increased pressure.
The time for performing the reaction in the second step is preferably 3 to 48 hours.

In the method for synthesizing the boron-containing compound represented by the general formula (16), one of at least one substituent of X ^{5 to} X ⁸ is exchanged with another substituent after the second step. Alternatively, a plurality of steps may be performed. For example, when any of X ^{5 to} X ⁸ is a halogen atom, Still cross coupling reaction, Suzuki-Miyaura cross coupling reaction, Sonogashira cross coupling reaction, Heck cross coupling reaction, Hiyama coupling reaction, The halogen atom can be exchanged for the substituent X by using Negishi coupling reaction or the like.
Moreover, as reaction conditions for the above coupling reaction, reaction conditions under which each coupling reaction is usually performed can be appropriately employed.

The boron-containing compound represented by the general formula (16) is most preferably a boron-containing compound represented by the general formula (1).

Moreover, as a boron containing compound used for the said 2nd material, the boron containing compound represented by following General formula (18) is also preferable.

(In the general formula (18), a dotted circular arc indicates that a ring structure is formed together with a skeleton portion represented by a solid line. A dotted line portion in the skeleton portion represented by a solid line is a pair connected by a dotted line. The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ⁵ and Q ⁶ are the same. Alternatively, it is a linking group in the skeleton part represented by a solid line, and at least a part thereof forms a ring structure together with a dotted arc part, and may have a substituent group, X ⁹ , X ¹⁰ , X ¹¹ and X ¹² are the same or different and each represents a hydrogen atom, a monovalent substituent that serves as a substituent of the ring structure, or a direct bond, and a plurality of X ¹¹ and X ¹² are bonded to the ring structure forming the dotted arc portion. which may be .A ¹ are the same or different, Table divalent radical Structural units in parentheses marked with .n ^{2 is, X 9, X 10, X} 11 and any two is bonded to adjacent structural units ^.n 2, ^{n 3} of ^{X 12} are each independently Are the same or different and represent a number of 1 or more.)

Q ⁵ and Q ⁶ in the general formula (18) are the same as Q ³ and Q ⁴ in the general formula (16), respectively, and preferred forms are also the same. That is, Q ⁵ and Q ⁶ are preferably the same or different and each represents a linking group having 1 carbon atom.
In the general formula (18), the dotted arc, the dotted line portion in the skeleton represented by the solid line, and the arrow from the nitrogen atom to the boron atom have the same meaning as in the general formula (16), and the dotted arc A preferred structure is also the same as that of the general formula (16). That is, the boron-containing compound represented by the general formula (18) is preferably a boron-containing compound represented by the following general formula (19).

(In the general formula (19), arrows from a nitrogen atom to a boron atom, X ⁹ , X ¹⁰ , X ¹¹ , X ¹² , A ¹ , n ² and n ³ are the same as in the general formula (18). The bond with the structural unit adjacent to the structural unit in parentheses marked with ² is the same as in the general formula (18).)

In the general formula (18), n ² represents the number of structural units in parentheses marked with n ^2, it represents a number of 1 or more. n ³ represents the number of structural units in parentheses with n ³ and represents a number of 1 or more. n ² and n ³ are independently the same or different and each represents a number of 1 or more, and this has the following meaning. n ² and n ³ are independent numbers. For this reason, n ² and n ³ may be the same number or different numbers.

The boron-containing compound represented by the general formula (18) may have one or more repeating unit structures represented by the general formula (18). Boron-containing compound, if having a plurality of repeating structures represented by the general formula (18), and n ^2, n ³ in a certain structure, and n ^2, n ³ in the adjacent structure, may be the same It may be different.

Therefore, the boron-containing compound represented by the general formula (18) has two or more alternating copolymers (two or more repeating structures represented by the general formula (18)). In the structure represented, n ² is the same number, and n ³ is the same number), a block copolymer (having one repeating structure represented by the general formula (18), and n ² , n ³ or more), a random copolymer (having two or more repeating structures represented by the above general formula (18), and at least among the structures represented by the plurality of general formulas (18) 1 or any of n ² and n ³ or both are different from n ² and n ³ in other structures).
Among these, the boron-containing compound represented by the general formula (18) is preferably an alternating copolymer.

In the general formula (18), X ⁹ , X ¹⁰ , X ¹¹ and X ¹² are the same or different and each represents a hydrogen atom, a monovalent substituent which serves as a substituent of a ring structure, or a direct bond.
In the general formula (18), any two of X ⁹ , X ¹⁰ , X ¹¹ and X ¹² form a bond as part of the main chain of the polymer. Among X ^{9 to} X ¹² , those that form a bond as part of the polymer main chain are directly bonded. Of X ⁹ , X ¹⁰ , X ¹¹ and X ¹² , those not involved in the polymerization are hydrogen atoms or monovalent substituents.
Among X ⁹ , X ¹⁰ , X ¹¹ and X ¹² , specific examples and preferred monovalent groups that do not participate in polymerization are X ⁵ and X ⁶ of the boron-containing compound represented by the general formula (16). These are the same as the specific examples and preferred ones.

In the boron-containing compound represented by the general formula ^(18), of ^{X 9,} X 10, X ¹¹ and ^{X 12,} direct ^bond, any of those ^{X 9,} X 10, X ¹¹ and ^{X 12} However, X ⁹ and X ¹⁰ or X ¹¹ and X ¹² are preferably a direct bond. In this case, the boron-containing compound represented by the general formula (18) is a polymer having a structure of a repeating unit represented by the following general formula (20) or general formula (21).

(In the general formulas (20) and (21), a dotted arc, a dotted line portion in a skeleton represented by a solid line, an arrow from a nitrogen atom to a boron atom, Q ⁵ , Q ⁶ , A ¹ , n ² and n ³ Is the same as in general formula (18) In formula (20), X ⁹ and X ¹⁰ represent a direct bond, and X ¹¹ and X ¹² represent a hydrogen atom or a monovalent substituent. In formula (21), X ¹¹ and X ¹² represent a direct bond, and X ⁹ and X ¹⁰ represent a hydrogen atom or a monovalent substituent.)

When the boron-containing compound used as the second material is a polymer, the weight average molecular weight is preferably 5,000 to 1,000,000. When the weight average molecular weight is in such a range, the organic thin film can be easily thinned by a method of applying a coating composition containing the second material and the first material. The weight average molecular weight is more preferably 10,000 to 500,000, still more preferably 30,000 to 200,000.
The said weight average molecular weight can be measured with the following apparatuses and measurement conditions by the gel permeation chromatography (GPC) by polystyrene conversion.
High-speed GPC device: HLC-8220GPC (manufactured by Tosoh Corporation)
Developing solvent Chloroform column TSK-gel GMHXL x 2 Eluent flow rate 1 ml / min
Column temperature 40 ° C

A ¹ in the general formula (18) is not particularly limited as long as it is a divalent group, but is preferably an alkenyl group, an arylene group, or a divalent aromatic heterocyclic group.
The arylene group is an atomic group obtained by removing two hydrogen atoms from an aromatic hydrocarbon, and the number of carbon atoms constituting the ring is usually about 6 to 60, preferably 6 to 20. The aromatic hydrocarbon includes those having a condensed ring and those having two or more independent benzene rings or condensed rings bonded directly or via a group such as vinylene.

Examples of the arylene group include groups represented by general formulas (15-1) to (15-23) shown below. Among these, a phenylene group, a biphenylene group, a fluorene-diyl group, and a stilbene-diyl group are preferable.

In general formulas (15-1) to (15-23), R's are the same or different and are a hydrogen atom, a halogen atom, an alkyl group, an alkyloxy group, an alkylthio group, an alkylamino group, an aryl group, an aryloxy group. Group, arylthio group, arylalkyl group, arylalkyloxy group, arylalkylthio group, acyl group, acyloxy group, amide group, imido group, imine residue, amino group, substituted amino group, substituted silyl group, substituted silyloxy group, substituted Silylthio group, substituted silylamino group, monovalent heterocyclic group, heteroaryloxy group, heteroarylthio group, arylalkenyl group, arylethynyl group, carboxyl group, alkyloxycarbonyl group, aryloxycarbonyl group, arylalkyloxycarbonyl group , Heteroaryl oxy It represents a carbonyl group or a cyano group.

In the general formulas (15-1) to (15-23), the line attached across the ring structure like the line indicated by xy in the general formula (15-1) has a ring structure. It means that it is directly bonded to an atom in the bonded moiety. That is, in the general formula (15-1), it means that it is directly bonded to any of the carbon atoms constituting the ring indicated by the line xy, and the bonding position in the ring structure is not limited.
Further, in the general formulas (15-1) to (15-23), the line attached to the apex of the ring structure is the same as the line indicated by z- in the general formula (15-10). It means that the ring structure is directly bonded to the atom in the bonded moiety.
Moreover, the line with R attached so as to intersect the ring structure means that R may be bonded to the ring structure one or plural, and the bond The position is not limited.

In the general formulas (15-1) to (15-10) and (15-15) to (15-20), the carbon atom may be replaced with a nitrogen atom, and the hydrogen atom is replaced with a fluorine atom. It may be.

The said bivalent aromatic heterocyclic group means the remaining atomic groups remove | excluding two hydrogen atoms from the aromatic heterocyclic compound, and carbon number which comprises a ring is about 3-60 normally. The aromatic heterocyclic compound includes not only carbon atoms but also heteroatoms such as oxygen, sulfur, nitrogen, phosphorus, boron, arsenic, etc., as the elements constituting the ring among aromatic organic compounds having a cyclic structure. Also included within.

Examples of the divalent aromatic heterocyclic group include heterocyclic groups represented by the following general formulas (16-1) to (16-38).
In general formulas (16-1) to (16-38), R is the same as R in the arylene group. Y represents O, S, SO, SO ₂ , Se, or Te. The lines attached to intersect the ring structure, the lines attached to the apex of the ring structure, and the lines with R attached to intersect the ring structure are represented by the general formulas (15-1) to (15-23). ).
In general formulas (16-1) to (16-38), the carbon atom may be replaced with a nitrogen atom, and the hydrogen atom may be replaced with a fluorine atom.

A ¹ in the general formula (18) is (15-1), (15-9), (16-1), (16-9), (16-16), (16-17) among those described above. ) Is preferred, and (15-1) and (15-9) are more preferred. In this case, when producing an organic thin film by a method of applying a coating composition containing the second material, which is the boron-containing compound represented by the general formula (18), and the first material, excellent film forming properties Is obtained.

Although the manufacturing method in particular of the boron containing compound represented by the said General formula (18) is not restrict | limited, For example, it can manufacture with the manufacturing method of Unexamined-Japanese-Patent No. 2011-184430.
The boron-containing compound represented by the general formula (18) includes, for example, a boron-containing compound having a reactive group represented by the following general formula (22) and a compound represented by the following general formula (23). It is preferable to produce by reacting the monomer components to be included.

(In the general formula (22), the dotted arc, the dotted portion in the skeleton represented by the solid line, the arrow from the nitrogen atom to the boron atom, Q ⁵ and Q ⁶ are the same as in the general formula (18). ⁹ ′, X ¹⁰ ′, X ¹¹ ′ and X ¹² ′ are the same or different and each represents a hydrogen atom or a monovalent substituent serving as a substituent of a ring structure, and X ⁹ ′, X ¹⁰ ′, X ¹¹ ′ And at least two of X ¹² ′ are reactive groups that react with X ¹³ and X ¹⁴ of the following general formula (23).

^{X 13 -A 1 -X 14 (23} )
(Wherein, ^{A 1} is the same as in the general formula (18) ^{.X 13, X 14} represents a reactive group.)

When the boron-containing compound represented by the general formula (22) is reacted with the compound represented by the general formula (23), a boron-containing polymer represented by the general formula (18) is synthesized by a polycondensation reaction. The
Among X ⁹ ′ to X ¹² ′, a monovalent substituent other than the reactive group that reacts with X ¹³ and X ^{14 in} the general formula (23) is 1 in X ^{9 to} X ¹² in the general formula (18). The same as the valent substituent.

The combination of reactive groups capable of undergoing polycondensation reaction is preferably any of the following, and the boron-containing compound represented by the general formula (22) and the compound represented by the general formula (23) The polycondensation reaction is preferably carried out by a combination of reactive groups capable of undergoing any polycondensation reaction.
Boryl group and halogen atom, stannyl group and halogen atom, aldehyde group and phosphonium methyl group, vinyl group and halogen atom, aldehyde group and phosphonate methyl group, halogen atom and magnesium halide, halogen atom and halogen atom, halogen atom and silyl group , Halogen atoms and hydrogen atoms.

The monomer component used to produce the boron-containing compound represented by the general formula (18) includes a boron-containing compound represented by the general formula (22) and a compound represented by the general formula (23). As long as it contains, other monomers may be included.
When other monomers are included, the total of the boron-containing compound represented by the general formula (22) and the compound represented by the general formula (23) is 90 mol with respect to 100 mol% of the whole monomer components. % Or more, more preferably 95 mol% or more, and most preferably 100 mol%. That is, it is most preferable that the monomer component contains only the boron-containing compound represented by the general formula (22) and the compound represented by the general formula (23).

Examples of the other monomer include a boron-containing compound represented by the general formula (22) or a compound having a reactive group capable of reacting with the compound represented by the general formula (23). In addition, as said monomer component, the boron-containing compound represented by General formula (22) and the compound represented by General formula (23) may contain only 1 type, respectively, and contain 2 or more types. Also good.

The molar ratio of the boron-containing compound represented by the general formula (22) and the compound represented by the general formula (23) in the monomer component is preferably 100/0 to 10/90, more preferably. Is 70/30 to 30/70, most preferably 50/50.
Moreover, it is preferable to set suitably the solid content concentration of the monomer component in the case of a polymerization reaction in the range of 0.01 mass%-the maximum density | concentration which melt | dissolves in a solvent. If the solid content concentration is too dilute, the reaction efficiency is poor, and if it is too thick, the reaction may be difficult to control. Therefore, the preferable solid content concentration is 0.05 to 10% by mass.

The boron-containing compound represented by the general formula (18) is most preferably a boron-containing compound represented by the general formula (21-1) or (21-2). As the boron-containing compound represented by the general formula (18), in particular, the general formula (21-2) that is easily dissolved in a solvent and can easily prepare a coating composition containing the first material and the second material. The boron-containing compounds represented are preferred.
(In General Formula (21-1), n ⁵ represents a number of 1 or more.) (In General Formula (21-2), n ⁴ represents a number of 1 or more.)

In summary, when the boron-containing compound represented by the general formulas (14), (16), and (18) is used as the second material having an electron transporting property, the first material and the second material are included. A uniform organic thin film can be easily obtained by the method of applying the coating composition.
Further, since the boron-containing compounds represented by the general formulas (14), (16), and (18) have a deepest minimum unoccupied orbital (LUMO) energy, they are suitable as a material for an electron injection layer of an organic electroluminescence device. It is. Therefore, an organic thin film containing these boron-containing compounds as the second material is particularly suitable as an electron injection layer of an organic electroluminescence device.

When the organic electroluminescent element of the present invention includes the first material and the second material, the mass ratio of the first material to the second material (first material: second material) is 0.01: 99. It is preferably 9-10: 1. More preferably, it is 0.5: 1 to 40: 1, and further preferably 2: 1 to 20: 1. In such a mass ratio, the effect of improving the electron transport property and the electron injection property due to the organic electroluminescent element containing the first material and the second material becomes remarkable.

In the organic electroluminescent element of the present invention, the layer containing the first material and the layer containing the second material may contain other materials other than the first material and the second material.
It is preferable to use an electron transport material as the other material. As the electron transport material, for example, any conventionally known material may be used as the material of the electron transport layer of the organic electroluminescent element. Specifically, compounds similar to specific examples of the material for the electron transport layer described later can be used.

<Configuration of organic electroluminescent element>
Next, the structure of the organic electroluminescent element of the present invention will be described.
The organic electroluminescent element of the present invention has a structure in which a plurality of organic compound layers are laminated between an anode and a cathode.
The configuration of the organic electroluminescence device of the present invention is not particularly limited, but the cathode, the electron injection layer, and optionally the electron transport layer, the light emitting layer, the hole transport layer and / or the hole injection layer, and the anode layer in this order. It is preferable that the element is adjacent. Each of these layers may be composed of one layer, or may be composed of two or more layers.
In the organic electric field element having the above configuration, when the element does not have an electron transport layer, the electron injection layer and the light emitting layer are adjacent to each other. In addition, when the element has only one of the hole transport layer and the hole injection layer, the one layer is laminated adjacent to the light emitting layer and the anode, and the element transports the hole. When both the layer and the hole injection layer are provided, these layers are laminated adjacently in the order of the light emitting layer, the hole transport layer, the hole injection layer, and the anode.
The organic electroluminescent element of the present invention may be a top emission type that extracts light to the side opposite to the substrate, or may be a bottom emission type that extracts light to the substrate side.

Since the layer containing the first material in the present invention has excellent electron injection characteristics, the element of the present invention preferably has a layer containing the first material as an electron injection layer. By including the layer containing the first material as the electron injection layer, an element having low driving voltage and excellent characteristics can be obtained.

FIG. 1 is a schematic cross-sectional view for explaining an example of the organic electroluminescent element of the present invention. The organic electroluminescent element of this embodiment shown in FIG. 1 has a light emitting layer 5 between an anode 2 and a cathode 8. The organic electroluminescent element shown in FIG. 1 has an electron injection layer 7 between the cathode 8 and the light emitting layer 5. The organic electroluminescent element shown in FIG. 1 is an organic electroluminescent element having a forward structure in which an anode 2 is disposed between a substrate 1 and a light emitting layer 5.
The organic electroluminescent device of this embodiment comprises an anode 2, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, an electron injection layer 7 on a substrate 1. The cathode 8 has a laminated structure formed in this order.

"substrate"
Examples of the material of the substrate in the organic electroluminescent element of the present invention include a resin material and a glass material.
Examples of the resin material used for the substrate include polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyether sulfone, polymethyl methacrylate, polycarbonate, and polyarylate. When a resin material is used as the material for the substrate, an organic electroluminescent element having excellent flexibility is obtained, which is preferable.
Examples of the glass material used for the substrate include quartz glass and soda glass.

When the organic electroluminescent element of the present invention is of a bottom emission type, a transparent substrate is used as the substrate material.
When the organic electroluminescent element of the present invention is of a top emission type, not only a transparent substrate but also an opaque substrate may be used as a substrate material. Examples of the opaque substrate include a substrate made of a ceramic material such as alumina, a substrate in which an oxide film (insulating film) is formed on the surface of a metal plate such as stainless steel, and a substrate made of a resin material.

The average thickness of the substrate can be determined according to the material of the substrate, and is preferably 0.1 to 30 mm, more preferably 0.1 to 10 mm.
The average thickness of the substrate can be measured with a digital multimeter or a caliper.

"anode"
In the organic electroluminescent element of the present invention, examples of the material used for the anode include ITO, IZO, Au, Pt, Ag, Cu, Al, and alloys containing these. Among these, it is preferable to use ITO, IZO, Au, Ag, or Al as the material of the anode 9.

The average thickness of the anode is not particularly limited, but is preferably 10 to 1000 nm, and more preferably 30 to 150 nm. Even when an opaque material is used as the anode material, for example, by setting the average thickness to about 10 to 30 nm, it can be used as a transparent anode in a top emission type organic electroluminescence device.
The average thickness of the anode can be measured at the time of film formation of the anode with a crystal oscillator thickness meter.

"Hole injection layer"
In the organic electroluminescent element of the present invention, the material used for the hole injection layer is dipyrazino [2,3-f: 2 ′, 3′-h] quinoxaline-2,3,6,7,10,11-. Examples include hexacarbonitrile (HAT-CN) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane (F4-TCNQ).

Although the average thickness of the said positive hole injection layer is not specifically limited, It is preferable that it is 1-1000 nm, and it is more preferable that it is 5-50 nm.
The average thickness of the hole injection layer can be measured at the time of film formation with a crystal oscillator thickness meter.

`` Hole transport layer ''
In the organic electroluminescent device of the present invention, as the hole transporting organic material used for the hole transporting layer, various p-type high molecular materials (organic polymers) and various p-type low molecular materials may be used alone or in combination. Can do.
Specifically, as a material for the hole transport layer, for example, N, N′-di (1-naphthyl) -N, N′-diphenyl-1,1′-biphenyl-4,4′-diamine (α- NPD), N4, N4′-bis (dibenzo [b, d] thiophen-4-yl) -N4, N4′-diphenylbiphenyl-4,4′-diamine (DBTPB), polyarylamine, fluorene-arylamine Polymer, fluorene-bithiophene copolymer, poly (N-vinylcarbazole), polyvinylpyrene, polyvinylanthracene, polythiophene, polyalkylthiophene, polyhexylthiophene, poly (p-phenylene vinylene), polytinylene vinylene, pyrene formaldehyde resin And ethylcarbazole formaldehyde resin or derivatives thereof. These materials for the hole transport layer 7 can also be used as a mixture with other compounds. As an example, poly (3,4-ethylenedioxythiophene / styrene sulfonic acid) (PEDOT / PSS) and the like can be given as a mixture containing polythiophene used as a material for the hole transport layer 7.

Although the average thickness of the said positive hole transport layer is not specifically limited, It is preferable that it is 10-150 nm, and it is more preferable that it is 20-100 nm.
The average thickness of the hole transport layer can be measured, for example, by a stylus profilometer or spectroscopic ellipsometry.

"Light emitting layer"
In the organic electroluminescent element of the present invention, as a material for forming the light emitting layer, any material that can be usually used as the material of the light emitting layer may be used, or a mixture thereof may be used. Specifically, for example, as a light-emitting layer, bis [2- (2-benzothiazolyl) phenolato] zinc (II) (Zn (BTZ) ₂ ) and tris [1-phenylisoquinoline] iridium (III) (Ir (piq ) ₃ ).
The material for forming the light emitting layer may be a low molecular compound or a high molecular compound. In the present invention, the low molecular weight material means a material that is not a polymer material (polymer), and does not necessarily mean an organic compound having a low molecular weight.

Examples of the polymer material forming the light emitting layer include polyacetylene compounds such as trans-type polyacetylene, cis-type polyacetylene, poly (di-phenylacetylene) (PDPA), and poly (alkylphenylacetylene) (PAPA); (Para-phenvinylene) (PPV), poly (2,5-dialkoxy-para-phenylenevinylene) (RO-PPV), cyano-substituted-poly (para-phenvinylene) (CN-PPV), poly (2 Polyparaphenylene vinylene compounds such as -dimethyloctylsilyl-para-phenylene vinylene (DMOS-PPV), poly (2-methoxy, 5- (2'-ethylhexoxy) -para-phenylene vinylene) (MEH-PPV) Poly (3-alkylthiophene) (PAT), poly (oxy Polythiophene compounds such as (Lopyrene) triol (POP); poly (9,9-dialkylfluorene) (PDAF), poly (dioctylfluorene-alt-benzothiadiazole) (F8BT), α, ω-bis [N, N ′ -Di (methylphenyl) aminophenyl] -poly [9,9-bis (2-ethylhexyl) fluorene-2,7-zyl] (PF2 / 6am4), poly (9,9-dioctyl-2,7-divinylene) Polyfluorene-based compounds such as fluorenyl-ortho-co (anthracene-9,10-diyl); poly (para-phenylene) (PPP), poly (1,5-dialkoxy-para-phenylene) (RO— Polyparaphenylene compounds such as PPP); polycarbazol such as poly (N-vinylcarbazole) (PVK) Polysilane compounds such as poly (methylphenylsilane) (PMPS), poly (naphthylphenylsilane) (PNPS), poly (biphenylylphenylsilane) (PBPS); and Japanese Patent Application No. 2010-230995, Examples thereof include boron compound-based polymer materials described in Japanese Patent Application No. 2011-6457.

Examples of the low molecular weight material forming the light emitting layer include a tricoordinate iridium complex having 2,2′-bipyridine-4,4′-dicarboxylic acid as a ligand, and factory (2-phenylpyridine). Iridium (Ir (ppy) ₃ ), 8-hydroxyquinoline aluminum (Alq ₃ ), tris (4-methyl-8 quinolinolate) aluminum (III) (Almq ₃ ), 8-hydroxyquinoline zinc (Znq ₂ ), (1, 10-phenanthroline) -tris- (4,4,4-trifluoro-1- (2-thienyl) -butane-1,3-dionate) europium (III) (Eu (TTA) ₃ (phen)), 2, Various metal complexes such as 3,7,8,12,13,17,18-octaethyl-21H, 23H-porphine platinum (II); Benzene compounds such as rilbenzene (DSB) and diaminodistyrylbenzene (DADSB); naphthalene compounds such as naphthalene and nile red; phenanthrene compounds such as phenanthrene; chrysene compounds such as chrysene and 6-nitrochrysene A perylene compound such as perylene, N, N′-bis (2,5-di-t-butylphenyl) -3,4,9,10-perylene-di-carboximide (BPPC); Coronene compounds; anthracene compounds such as anthracene and bisstyrylanthracene; pyrene compounds such as pyrene; 4- (di-cyanomethylene) -2-methyl-6- (para-dimethylaminostyryl) -4H-pyran A pyran compound such as (DCM); Gin compounds; stilbene compounds such as stilbene; thiophene compounds such as 2,5-dibenzoxazole thiophene; benzoxazole compounds such as benzoxazole; benzimidazole compounds such as benzimidazole; 2,2 ′ Benzothiazole compounds such as-(para-phenylenedivinylene) -bisbenzothiazole; butadiene compounds such as bistyryl (1,4-diphenyl-1,3-butadiene) and tetraphenylbutadiene; naphthalimide Naphthalimide compounds; coumarin compounds such as coumarin; perinone compounds such as perinone; oxadiazole compounds such as oxadiazole; aldazine compounds; 1,2,3,4,5-pentaphenyl- 1,3-cyclopen Cyclopentadiene compounds such as diene (PPCP); quinacridone compounds such as quinacridone and quinacridone red; pyridine compounds such as pyrrolopyridine and thiadiazolopyridine; 2,2 ′, 7,7′-tetraphenyl- Spiro compounds such as 9,9′-spirobifluorene; metal or metal-free phthalocyanine compounds such as phthalocyanine (H ₂ Pc) and copper phthalocyanine; and JP2009-155325A and JP2011-184430A And boron compound materials described in Japanese Patent Application No. 2011-6458.

Although the average thickness of the said light emitting layer is not specifically limited, It is preferable that it is 10-150 nm, and it is more preferable that it is 20-100 nm.
The average thickness of the light emitting layer may be measured with a stylus profilometer, or may be measured at the time of forming the light emitting layer with a crystal resonator film thickness meter.

"Electron transport layer"
In the organic electroluminescent element of the present invention, any material that can be usually used as the material for the electron transport layer may be used as the material for the electron transport layer. Further, the electron transport layer may contain the second material of the present invention or be made of the second material.
Specific examples of materials that can be normally used as the material for the electron transport layer include phosphine oxide derivatives such as phenyl-dipyrenylphosphine oxide (POPy ₂ ), tris-1,3,5- (3 ′-(pyridine). Pyridine derivatives such as -3 ″ -yl) phenyl) benzene (TmPhPyB), quinoline derivatives such as (2- (3- (9-carbazolyl) phenyl) quinoline (mCQ)), 2-phenyl-4,6 -Pyrimidine derivatives such as bis (3,5-dipyridylphenyl) pyrimidine (BPyPPM), pyrazine derivatives, phenanthroline derivatives such as bathophenanthroline (BPhen), 2,4-bis (4-biphenyl) -6- (4 ' Like-(2-pyridinyl) -4-biphenyl)-[1,3,5] triazine (MPT) Triazine derivatives, triazole derivatives such as 3-phenyl-4- (1′-naphthyl) -5-phenyl-1,2,4-triazole (TAZ), oxazole derivatives, 2- (4-biphenylyl) -5- ( Oxadiazole derivatives such as 4-tert-butylphenyl-1,3,4-oxadiazole) (PBD), 2,2 ′, 2 ″-(1,3,5-bentriyl) -tris (1 -Imidazole derivatives such as phenyl-1-H-benzimidazole (TPBI), aromatic ring tetracarboxylic anhydrides such as naphthalene and perylene, bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (Zn (BTZ)) ₂ ), various metal complexes represented by tris (8-hydroxyquinolinato) aluminum (Alq3), 2,5-bis (6 ′-(2 ′) , 2 ″ -bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), organosilane derivatives represented by silole derivatives, Japanese Patent Application No. 2012-228460, Japanese Patent Application No. 2015-503053, Examples thereof include boron-containing compounds described in Japanese Patent Application No. 2015-038772, Japanese Patent Application No. 2015-081108, and Japanese Patent Application No. 2015-081109, and one or more of these can be used.
Among these electron transport layer material, particularly, phosphine oxide derivatives such as Popy _2, metal complexes such as Alq _3, it is preferable to use pyridine derivatives such as TmPhPyB.

Although the average thickness of the said electron carrying layer is not specifically limited, It is preferable that it is 10-150 nm, and it is more preferable that it is 20-100 nm.
The average thickness of the electron transport layer can be measured by a stylus profilometer or spectroscopic ellipsometry.

"Electron injection layer"
In the organic electroluminescence device of the present invention, the electron injection layer is a layer that improves the rate of electron injection from the cathode to the light emitting layer and the electron transport property, and includes the first material.
The average thickness of the electron injection layer is preferably 5 to 100 nm, and more preferably 10 to 50 nm. When the average thickness of the electron injection layer is 5 nm or more, a method of applying a coating composition containing the first material and the second material or a method of laminating and forming the first material and the second material is used. By forming the electron injection layer, an electron injection layer having a smooth surface can be obtained, and leakage during the production of the organic electroluminescent element can be sufficiently prevented. Moreover, when the average thickness of an electron injection layer is 100 nm or less, the raise of the drive voltage of an organic electroluminescent element by providing an electron injection layer can fully be suppressed.
In the case where the first material and the second material are respectively laminated and formed, the entire laminated film may constitute an electron injection layer, but the second material is an electron transport layer, a light emitting layer, or the like. It may be included in a layer adjacent to the electron injection layer, and the layer of the second material may constitute a layer other than the electron injection layer. For example, when the first material is an electron injection layer and the second material is included in the electron transport layer, or the organic electroluminescent element is an element having no electron transport layer, and the first material is the electron injection layer The case where the layer of the second material is included in the light emitting layer is also included in the present invention. As described above, among these, having the layer containing the second material between the light emitting layer and the layer containing the first material is a preferred embodiment of the organic electroluminescence device of the present invention. More preferably, the layer including the second material is adjacent to the layer including the second material.
The average thickness of the electron injection layer can be measured by, for example, a stylus profilometer or spectroscopic ellipsometry.

"cathode"
In the organic electroluminescence device of the present invention, the cathode material may be ITO (indium tin oxide), IZO (indium zinc oxide), FTO (fluorine tin oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , Al Examples thereof include oxide conductive materials such as ZnO. Among these, it is preferable to use ITO, IZO, or FTO as the cathode material.

The average thickness of the cathode is not particularly limited, but is preferably 10 to 500 nm, and more preferably 100 to 200 nm.
The average thickness of the cathode can be measured by a stylus profilometer or spectroscopic ellipsometry.

"Sealing"
The organic electroluminescent element of the present invention may be sealed as necessary.
The sealing method is not particularly limited. For example, even if the sealing method is performed by a sealing container having a concave space for housing the organic electroluminescent element and an adhesive that bonds the edge of the sealing container and the substrate. Good. Alternatively, the organic electroluminescent element may be housed in a sealing container and sealed by filling a sealing material made of ultraviolet (UV) curable resin or the like. A sealing member comprising a plate member disposed on the cathode and a frame member disposed along an edge of the plate member facing the cathode; and a space between the plate member and the frame member and the frame member It may be sealed using an adhesive that bonds between the substrate and the substrate.

When sealing an organic electroluminescent element using the said sealing container or sealing member, you may arrange | position the desiccant which absorbs a water | moisture content in a sealing container or the inner side of a sealing member. Moreover, you may use the material which absorbs a water | moisture content as a sealing container or a sealing member. Further, a space may be formed in the sealed sealing container or inside the sealing member.

As a material of the sealing container or the sealing member used when sealing the organic electroluminescent element, a resin material, a glass material, or the like can be used. Examples of the resin material and the glass material used for the sealing container or the sealing member include the same materials as those used for the substrate.

2. Manufacturing method of organic electroluminescent element The organic electroluminescent element of the present invention has a structure in which a plurality of layers including a light emitting layer are laminated on an anode formed on a substrate, and the top of the laminated structure is a cathode. Since the layer having a certain structure and adjacent to the cathode includes a first material that is an organic material having an acid dissociation constant pKa of 1 or more, the layer includes a first material that is an organic material having an acid dissociation constant pKa of 1 or more. After the layer is formed, the cathode is formed on the layer containing the first material.
Such an organic electroluminescence device manufacturing method of the present invention, that is, an organic electroluminescence device having a structure in which a plurality of layers including a light emitting layer are laminated between a cathode and an anode formed on a substrate is manufactured. The method includes the steps of forming a layer containing a first material that is an organic material having an acid dissociation constant pKa of 1 or more, and forming a cathode on the layer containing the first material. The manufacturing method of the organic electroluminescent element characterized by including is also one of this invention.

As described above, the organic electroluminescent element of the present invention is formed by laminating a first material and a second material, the first material is an electron injection layer, and the second material is electron transport. The organic electroluminescent element contained in the layer, or formed by mixing the first material and the second material to form a film, and the mixed film forming layer serves as an electron injection layer or an electron transport layer. It is also preferable to use an organic electroluminescent device.
A method for manufacturing such an organic electroluminescent element, the above-described manufacturing method includes a step of forming a layer of a second material that transports electrons after forming a light emitting layer, and a step of forming an acid layer after forming the layer of second material. Forming a layer of a first material which is an organic material having a dissociation constant pKa of 1 or more, or forming a layer containing the first material and the second material after forming a light emitting layer. It is preferable to include.

The step of forming the layer containing the first material is a step of applying a coating composition containing the first material on the surface to be formed, or forming a film on the surface to be formed by the vapor of the first material. It is preferable that it is a process.
Moreover, when the said manufacturing method includes the process of forming the layer containing 2nd material, it is preferable that this process is a process of apply | coating the coating composition containing 2nd material on a to-be-formed surface.

When the manufacturing method includes a step of forming a layer including the first material and the second material after forming the light emitting layer, a layer including the first material and the second material is applied on the surface to be formed. It is preferable to form.

As described above, since the first material, which is an organic material having a pKa of 1 or more, is a material having an ability to extract protons (H ⁺ ) from other materials, the electron injection from the cathode can be sufficiently advanced. The first material is preferably present more on the cathode side. Therefore, the electron injection layer preferably has a concentration distribution such that the concentration of the first material decreases from the cathode side toward the electron transport layer side.
As a method for forming an electron injection layer having such a concentration distribution, a solution containing a second material is applied on a light emitting layer or an electron transport layer to form a coating film, and then a solution containing the first material is added to the first material. The method of apply | coating on the coating film of 2 materials is mentioned.
Such a method is a preferred embodiment of the method for producing an organic electroluminescent device of the present invention. That is, in the method for producing an organic electroluminescent element of the present invention, the step of forming the second material layer is a step of applying a coating composition containing the second material on the surface to be formed, or the first material. One of the preferred embodiments of the method for producing an organic electroluminescent element of the present invention is that the step of forming the layer is a step of applying a coating composition containing the first material on the surface to be formed. .
The concentration distribution can be measured by TOF-SIMS (time-of-flight secondary ion mass spectrometry) or the like.

When the layer containing the first material or the layer containing the second material is formed by applying a solution, it is preferable to apply an annealing treatment after applying the coating composition. The annealing treatment is preferably performed at 70 to 200 ° C. for 0.1 to 5 hours in a nitrogen atmosphere or in the air. By performing such annealing treatment, the organic thin film can be formed by evaporating the solvent.

In the organic electroluminescent device of the present invention, the method for forming the layer formed from the organic compound is not particularly limited, and various methods can be appropriately used according to the characteristics of the material. Spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, slit coating method, dip coating method, spray coating method, screen printing method, flexographic printing method, offset The film can be formed using various coating methods such as a printing method and an ink jet printing method. Among these, the spin coat method and the slit coat method are preferable because the film thickness can be more easily controlled. Sputtering method, vacuum deposition method, sol-gel method, spray pyrolysis (SPD) method, atomic layer deposition (ALD) method, gas phase film forming method, liquid phase film forming method, ESDUS when not applied or when solvent solubility is low (Evaporative Spray Deposition from Ultra-dilute Solution) method or the like can be used.

When the layer formed from the organic compound including the first material and the second material is formed by applying an organic compound solution, examples of the solvent used for dissolving the organic compound include nitric acid, sulfuric acid, and ammonia. Inorganic solvents such as hydrogen peroxide, water, carbon disulfide, carbon tetrachloride, ethylene carbonate, methyl ethyl ketone (MEK), acetone, diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), cyclohexanone, etc. Ketone solvents, methanol, ethanol, isopropanol, ethylene glycol, diethylene glycol (DEG), alcohol solvents such as glycerin, diethyl ether, diisopropyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, tetrahydrofuran (THF , Tetrahydropyran (THP), anisole, ether solvents such as diethylene glycol dimethyl ether (diglyme), diethylene glycol ethyl ether (carbitol), cellosolv solvents such as methyl cellosolve, ethyl cellosolve, phenyl cellosolve, hexane, pentane, heptane, cyclohexane, etc. Aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents such as toluene, xylene and benzene, aromatic heterocyclic compounds solvents such as pyridine, pyrazine, furan, pyrrole, thiophene and methylpyrrolidone, N, N-dimethylformamide (DMF), amide solvents such as N, N-dimethylacetamide (DMA), halogen compound solvents such as chlorobenzene, dichloromethane, chloroform, 1,2-dichloroethane, ethyl acetate, vinegar Ester solvents such as methyl and ethyl formate, sulfur compound solvents such as dimethyl sulfoxide (DMSO) and sulfolane, nitrile solvents such as acetonitrile, propionitrile, and acrylonitrile, organics such as formic acid, acetic acid, trichloroacetic acid, and trifluoroacetic acid Examples include various organic solvents such as acid solvents, or mixed solvents containing these.
Among these, as the solvent, a nonpolar solvent is suitable, for example, an aromatic hydrocarbon solvent such as xylene, toluene, cyclohexylbenzene, dihydrobenzofuran, trimethylbenzene, tetramethylbenzene, pyridine, pyrazine, furan, Examples include aromatic heterocyclic compound solvents such as pyrrole, thiophene, and methylpyrrolidone, and aliphatic hydrocarbon solvents such as hexane, pentane, heptane, and cyclohexane. These can be used alone or in combination.

The cathode, anode, and metal oxide layer can be formed by sputtering, vacuum deposition, sol-gel, spray pyrolysis (SPD), atomic layer deposition (ALD), vapor deposition, or liquid deposition. Or the like. Metal foil bonding can also be used to form the anode and cathode. These methods are preferably selected according to the characteristics of the material of each layer, and the manufacturing method may be different for each layer. When forming a metal oxide layer on an organic compound layer, it is more preferable to form using a vapor-phase film-forming method among these. According to the vapor deposition method, the organic compound layer can be formed cleanly and in good contact with the adjacent layer without breaking the surface of the organic compound layer.

The organic electroluminescent element of the present invention can change the emission color by appropriately selecting the material of the organic compound layer, and can also obtain a desired emission color by using a color filter or the like in combination. Therefore, it can be suitably used as a light emitting part of a display device or a lighting device. In particular, when the organic electroluminescent element is an element having an inverse structure, a display device combined with an oxide TFT is suitable because of the characteristic of the inverse structure.
Such a display device including the organic electroluminescent element of the present invention and an illumination device including the organic electroluminescent element of the present invention are also one aspect of the present invention.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

(Synthesis Example 1)
Synthesis of Boron-Containing Compound A By the following reactions 1-5, the following boron-containing compound A (2- [3-dibenzoboryl-5- {3- (pyridin-3-yl) phenyl} thiophen-2-yl] -5 -{3- (pyridin-3-yl) phenyl} pyridine) was synthesized.

(Reaction 1) 5-Bromo-2- (thiophen-2-yl) pyridine was synthesized according to the following reaction formula.

2-thiopheneboronic acid (4.99 g), 3-bromo-6-iodopyridine (12.18 g), tetrakistriphenylphosphine palladium (0) (Pd (PPh3) 4, 2.25 g) in toluene (150 ml) Dissolved, an aqueous potassium carbonate solution (16.17 g dissolved in 39 ml of water) was added thereto, and the mixture was stirred at 120 ° C. for 18 hours. After the reaction, the reaction solution is returned to room temperature, washed with water, the organic layer is dried over sodium sulfate and concentrated by filtration. The residue is purified by silica gel column chromatography to obtain crude 5-bromo-2- (thiophen-2-yl) pyridine as 9%. .3 g was obtained. Without further purification, it proceeded to the next reaction.

(Reaction 2) 5-Bromo-2- (5-bromothiophen-2-yl) pyridine was synthesized according to the following reaction formula.

9.3 g of 5-bromo-2- (thiophen-2-yl) pyridine was dissolved in dehydrated chloroform (200 ml), N-bromosuccinimide (NBS, 6.9 g) was added thereto, and the mixture was stirred at room temperature overnight. After the reaction, it was washed with water, the organic layer was dried over sodium sulfate and concentrated by filtration. The residue was subjected to silica gel column chromatography to obtain 10.3 g of crude 5-bromo-2- (5-bromothiophen-2-yl) pyridine. It was. Without further purification, it proceeded to the next reaction.

(Reaction 3) 5-Bromo-2- (5-bromo-3- (dibromoboryl) thiophen-2-yl) pyridine was synthesized according to the following reaction formula.

Dissolve 10.3 g of 5-bromo-2- (5-bromothiophen-2-yl) pyridine in dichloroethane (DCE, 200 ml), add diisopropylethylamine (iPr2EtN, 5.7 ml) to the reactor and add −78 After cooling to ° C., boron tribromide (BBr3, 1 mol / L dichloromethane solution, 81.3 ml) was added dropwise thereto. After dropwise addition of the entire amount, the reaction was stirred for 1 hour at room temperature and overnight at 50 ° C. After the reaction, hexane was added and the precipitated solid was collected by filtration, washed with chloroform and dried to obtain 11.5 g of 5-bromo-2- (5-bromo-3- (dibromoboryl) thiophen-2-yl) pyridine. It was.

(Reaction 4) 5-Bromo-2- (5-bromo-3- (5H-dibenzo [b, d] borol-5-yl) thiophen-2-yl) pyridine was synthesized according to the following reaction formula.

After the activated magnesium (0.7 g) was activated by heating and drying, dehydrated diethyl ether (26 ml) and 2,2′-dibromobiphenyl (4.0 g) were added thereto, and the mixture was stirred at room temperature for 24 hours at 40 ° C. The reaction was stirred for 1 hour. After adding dehydrated toluene (130 ml) and cooling to −78 ° C., 5-bromo-2- (5-bromo-3- (dibromoboryl) thiophen-2-yl) pyridine (6.3 g) was added, and the mixture was brought to room temperature. The temperature was raised and the reaction was stirred overnight. After the reaction, water was added, extracted with chloroform, washed with water, the organic layer was dried over sodium sulfate and concentrated by filtration. The residue was purified by silica gel column chromatography, 5-bromo-2- (5-bromo-3- (5H- 6.0 g of dibenzo [b, d] borol-5-yl) thiophen-2-yl) pyridine was obtained.

(Reaction 5) A boron-containing compound A was synthesized according to the following reaction formula.

In a reaction vessel, 5-bromo-2- (5-bromo-3- (5H-dibenzo [b, d] borol-5-yl) thiophen-2-yl) pyridine (1.0 g), 3- (pyridine-3 -Yl) -1-pinacolatoborylbenzene (1.46 g), palladium acetate (16 mg), S-Phos (68 mg), potassium phosphate (2.65 g), toluene (20 mL), distilled water (1 drop). I put it in. This suspension was stirred for 10 minutes while bubbling with argon, then stirred at 90 ° C. for 6 hours, and the temperature was raised to 110 ° C. and further heated for 24 hours. After allowing to cool, the suspension was filtered, the filtrate was concentrated, and the resulting residue was purified by silica gel column chromatography to obtain a yellow viscous liquid. This was dissolved in toluene and heated, and the solid precipitated after standing to cool was collected by filtration. Further, this was purified by GPC and then recrystallized from a toluene / heptane mixed solution to obtain a boron-containing compound A. (0.42g, 32%)
The ¹ H-NMR measurement result of the obtained boron-containing compound A is shown in FIG.

(Production of organic electroluminescence device)
Example 1
[1] A commercially available transparent glass substrate with an ITO electrode layer having an average thickness of 0.7 mm was prepared. At this time, the ITO electrode (anode) of the substrate used was patterned to a width of 2 mm. This substrate was subjected to ultrasonic cleaning in acetone and isopropanol for 10 minutes, respectively, and then steam cleaning in isopropanol for 5 minutes. The substrate was dried by nitrogen blowing and UV ozone cleaning was performed for 20 minutes.
[2] This substrate is set on a spin coater, and an aqueous dispersion of poly (3,4-ethylenedioxythiophene / styrene sulfonic acid) (PEDOT / PSS) (manufactured by Heraeus, CH8000) is added dropwise at a rate of 2000 The positive hole injection layer made of PEDOT / PSS was formed on the anode by rotating for 60 seconds and further drying on a hot plate at 130 ° C. for 10 minutes. The average thickness of the hole injection layer was 50 nm. The average thickness of the hole injection layer was measured with a stylus type step gauge.
[3] A 2 wt% xylene solution of poly (dioctylfluorene-alt-benzothiadiazole) (F8BT) (molecular weight 54000) was prepared. The substrate produced in the above step [2] was set on a spin coater. An F8BT-xylene solution was dropped on the hole injection layer formed in the above step [2] and rotated at 2,000 rpm for 60 seconds to form a light emitting layer made of F8BT on the interlayer layer. The average thickness of the light emitting layer was 50 nm. The average thickness of the light emitting layer was measured with a stylus type step gauge.
[4] The substrate produced in the above step [3] was set on a spin coater. An ethanol solution (0.5 wt%) of 1,5-diazabicyclo [4.3.0] nonene-5 (DBN) is dropped on the light-emitting layer formed in the above step [3], and is 30 at 2000 rpm. Rotating for 2 seconds, an ultrathin electron injection layer was formed on the light emitting layer.
[5] The substrate produced in the above step [4] was fixed to the substrate holder of the vacuum deposition apparatus. An aluminum wire (Al) was placed in an alumina crucible and set in a vapor deposition source. The inside of the vacuum vapor deposition apparatus was depressurized to about 1 × 10 ⁻⁴ Pa, and Al (cathode) was vapor-deposited on the electron injection layer so as to have an average thickness of 100 nm to produce an organic electroluminescence device. The average thickness of the cathode was measured at the time of film formation with a crystal oscillator thickness meter.

(Example 2)
In Step [4] of Example 1, an ethanol solution (0.5 wt%) of 2-dimethylaminopyridine (2-DMAP) was used instead of an ethanol solution (0.5 wt%) of DBN, and an ultrathin film electron was used. An organic electroluminescent element was produced in the same manner as in Example 1 except that the injection layer was formed.

(Comparative Example 1)
An organic electroluminescent element was produced in the same manner as in Example 1 except that Step [4] in Example 1 was omitted.

(Example 3)
In step [4] of Example 1, except that the substrate prepared in step [3] was placed in a sealed container containing DBN instead of DBN ethanol solution (0.5 wt%) and exposed to DBN vapor for 1 minute. Produced an organic electroluminescent device in the same manner as in Example 1.

(Example 4)
In step [4] of Example 1, ethoxyethanol in which the boron-containing compound A synthesized in Synthesis Example 1 was 0.25 wt% and DBN was 0.5 wt% instead of the DBN ethanol solution (0.5 wt%). An organic electroluminescence device was produced in the same manner as in Example 1 except that the solution was dropped and rotated at 2000 rpm for 30 seconds to form an ultrathin electron injection layer on the light emitting layer.

(Example 5)
In step [4] of Example 1, instead of the ethanol solution (0.5 wt%) of DBN, an ethoxy ethanol solution containing 0.25 wt% of the boron-containing compound A synthesized in Synthesis Example 1 was added dropwise every minute. After rotating at 2000 rpm for 30 seconds, a DBN ethanol solution (0.5 wt%) was dropped and rotated at 2000 rpm for 30 seconds to form a two-layer electron injection layer on the light-emitting layer. Except that, an organic electroluminescent element was produced in the same manner as in Example 1.

(Measurement of light emission characteristics of organic electroluminescence device)
About the organic electroluminescent element produced in Examples 1-5 and the comparative example 1, the voltage application and electric current measurement to an element were performed with the "2400 type source meter" by a Keithley company. In addition, the emission luminance was measured by “BM-7” manufactured by Topcon Corporation. The measurement was performed in an argon atmosphere. The results are shown in FIGS.
The element of Example 1 (FIG. 3) having the DBN coating film layer is about 4.3 V in voltage application, and the element of Example 2 (FIG. 4) having the 2-DMAP coating film layer is in the vicinity of 5 V voltage application. Thus, the device of Example 3 (FIG. 6) in which DBN is formed by vapor can confirm light emission from around 5.5 V, whereas Comparative Example 1 (FIG. 5) does not have a DBN or 2-DMAP layer. It was confirmed that this device emitted weak light from around voltage application 7V. From this result, it was confirmed that the DBN coating film and the 2-DMAP layer functioned effectively as an electron injection (and electron transport) layer.
Moreover, although the element of Example 3 formed the DBN film | membrane by short-time vapor | steam exposure, light emission has been confirmed from 5V vicinity. In the element of Example 3, it is expected that an element exhibiting better characteristics is provided by providing one layer made of an electron transporting material between the light emitting layer and the DBN film.
Furthermore, it was confirmed that the luminance of the device of Example 4 (FIG. 7) having a coating film of a composition obtained by mixing DBN and boron-containing compound A is significantly improved as compared with the device of Comparative Example 1. This is a result showing that the characteristics are further improved by mixing with boron-containing compound A which is an electron transporting material.
Further, from the result of Example 5 (FIG. 8), even when a DBN ultrathin film was laminated on the boron-containing compound A which is an electron transporting material, the same brightness as that of Example 4 was confirmed. As a result, even when laminated with an electron transporting material, the function is exhibited, and although it is not the exposure by the vapor of Example 3, it is clear that further improvement in characteristics can be seen by inserting one or more electron transporting layers. It became.

1: Substrate 2: Anode 3: Hole injection layer 4: Hole transport layer 5: Light emitting layer 6: Electron transport layer 7: Electron injection layer 8: Cathode

Claims (14)

An organic electroluminescent device having a structure in which a plurality of layers including a light emitting layer are laminated between a cathode and an anode formed on a substrate,
An organic electroluminescence device, wherein a layer adjacent to the cathode among the plurality of stacked layers includes a first material that is an organic material having an acid dissociation constant pKa of 1 or more. The first material is one or more compounds selected from the group consisting of tertiary amines, phosphazene compounds, guanidine compounds, heterocyclic compounds containing an amidine structure, hydrocarbon compounds having a ring structure, and ketone compounds. The organic electroluminescent element according to claim 1, wherein the organic electroluminescent element is provided. The organic electroluminescence device has a layer containing a second material for transporting electrons between the light emitting layer and the layer containing the first material, or the first material and the first material between the light emitting layer and the cathode. The organic electroluminescent element according to claim 1, comprising a layer containing two materials. The second material contains one or more compounds selected from the group consisting of boron-containing compounds represented by the following general formulas (14), (37), (39), (16) and (18). The organic electroluminescent element according to any one of claims 1 to 3.

(In the general formula (14), the dotted circular arc indicates that a ring structure is formed together with the skeleton part represented by the solid line. The dotted line part in the skeleton part represented by the solid line is a pair connected by the dotted line The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ¹ and Q ² are the same. or different, is a linking group in the skeleton moiety represented by the solid line, forms a ring structure at least partially with a circular arc portion of the dotted line, which may have a substituent .X ^1, X ^2, X ³ and X ⁴ are the same or different and each represents a hydrogen atom or a monovalent substituent serving as a substituent of the ring structure, and a plurality of X ³ and X ⁴ may be bonded to the ring structure forming the dotted arc portion. .n ¹ represents an integer of 2 to 10 .Y ¹ is a direct bond or ^{n 1} monovalent A linking group, each independently and structural parts other than ^{Y 1} present ^{one n,} ring structure to form an arc portion of the dotted ^line, either in ^{Q 1, Q 2, X 1} , X 2, X 3, X 4 Represents that they are joined at one location.)

(In the general formula (37), the dotted arcs are the same or different and represent that a ring structure is formed together with the skeleton part represented by the solid line. The dotted line part in the skeleton part represented by the solid line represents the dotted line. a pair of atoms connected by representing that may be linked by a double bond. arrow from nitrogen atom to boron atom, .R ¹⁸ ~ indicating that the nitrogen atom is coordinated to a boron atom R ^{21 s} are the same or different and each represents a hydrogen atom, a monovalent substituent that serves as a substituent of a ring structure, a divalent group, or a direct bond, R ¹⁸ , R ^19, and R ²¹ are each a dotted line A plurality of R ²⁰ may be bonded to the pyridine ring structure, and the ring to which R ²¹ is bonded is an aromatic heterocyclic ring. there .n ⁶ is an integer from 1 to 4 .n ⁷ is 0 or 1 If n ⁷ is 1, ^{Y 2} are, ^{n 6} divalent linking group, or represents a direct bond, independently and structural parts other than the ^{Y 2} present ^{six n, R 18, R 19,} R 20, ^or, if .n ⁷ indicating that it is bound by any one location in ^{R 21} is 0, ^{n 6} is ^1, at least one of R 18 ^{to R 21} is a substituent of the ring structure And a monovalent substituent.

(In the general formula (39), a dotted circular arc represents that a ring structure is formed together with a skeleton part represented by a boron atom or a solid line, and the ring structure is the same or different and is composed of one ring. The dotted structure in the skeleton represented by the solid line may be a double pair of atoms connected by a dotted line. An arrow from a nitrogen atom to a boron atom indicates that the nitrogen atom is coordinated to the boron atom, and Q ⁷ is a link in the skeleton part represented by a solid line. R ²² and R ²³ are the same or different and may be substituted with a hydrogen atom or a ring structure, at least part of which forms a ring structure together with a dotted arc portion. Monovalent substituent, divalent group, or direct bond as a base And a plurality bonded good .R ²⁴ and R ²⁵ even if the ring structure to form an arc portion of the dotted line, the same or different and each represents a hydrogen atom, a monovalent substituent, a divalent group or a direct R ²⁴ and R ²⁵ are bonded to each other and do not form a ring structure with a skeleton represented by a double line, and n ⁸ is an integer of 1 to 4. n ⁹ is If .n ⁹ is 1 is 0 or 1, ^{Y 3} is, ^{n 8} divalent linking group, or represents a direct bond, independently and structural parts other than ^{Y 3} present ^{eight n, R 22,} It represents bonding at any one of R ²³ , R ²⁴ , or R ^25. )

(In the general formula (16), a dotted circular arc indicates that a ring structure is formed together with a skeleton portion represented by a solid line. A dotted line portion in the skeleton portion represented by a solid line is a pair connected by a dotted line. The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ³ and Q ⁴ are the same. or different, is a linking group in the skeleton moiety represented by the solid line, forms a ring structure at least partially with a circular arc portion of the dotted line, which may have a substituent .X ^5, X ⁶ is X ⁷ and X ⁸ are the same or different and each represents a hydrogen atom or a monovalent substituent serving as a substituent of the ring structure, and X ⁷ and X ⁸ are the same or different and represent an electron transporting property 1 serving as a substituent of the ring structure. represents the valence of the substituent ^{.X 5, X 6,} X ⁷ and ^{X 8} are each point The ring structure to form an arc portion may be a plurality bonds.)

(In the general formula (18), a dotted circular arc indicates that a ring structure is formed together with a skeleton portion represented by a solid line. A dotted line portion in the skeleton portion represented by a solid line is a pair connected by a dotted line. The arrows from the nitrogen atom to the boron atom indicate that the nitrogen atom is coordinated to the boron atom, and Q ⁵ and Q ⁶ are the same. Alternatively, it is a linking group in the skeleton part represented by a solid line, and at least a part thereof forms a ring structure together with a dotted arc part, and may have a substituent group, X ⁹ , X ¹⁰ , X ¹¹ and X ¹² are the same or different and each represents a hydrogen atom, a monovalent substituent that serves as a substituent of the ring structure, or a direct bond, and a plurality of X ¹¹ and X ¹² are bonded to the ring structure forming the dotted arc portion. which may be .A ¹ are the same or different, Table divalent radical Structural units in parentheses marked with .n ^{2 is, X 9, X 10, X} 11 and any two is bonded to adjacent structural units ^.n 2, ^{n 3} of ^{X 12} are each independently Are the same or different and represent a number of 1 or more.) The second material is any one boron-containing compound represented by the following general formulas (1), (14-2), and (21-2) or a phosphine oxide derivative represented by the following general formula (2). The organic electroluminescent element according to any one of claims 1 to 4.

(In the general formula (21-2), ^{n 4} represents the number of 1 or more.)

6. The organic electroluminescence device according to claim 1, wherein the acid dissociation constant pKa of the first material is 11 or more. A display device comprising the organic electroluminescent element according to claim 1. An illuminating device comprising the organic electroluminescent element according to claim 1. A method for producing an organic electroluminescent device having a structure in which a plurality of layers including a light emitting layer are laminated between a cathode and an anode formed on a substrate,
The manufacturing method includes a step of forming a layer including a first material that is an organic material having an acid dissociation constant pKa of 1 or more;
And a step of forming a cathode on the layer containing the first material. The manufacturing method includes a step of forming a layer containing a second material that transports electrons after forming a light emitting layer, and an organic material having an acid dissociation constant pKa of 1 or more after forming the layer containing the second material Forming a layer comprising a first material that is, or
The method of manufacturing an organic electroluminescent element according to claim 9, further comprising forming a layer including the first material and the second material after forming the light emitting layer. 11. The organic electroluminescent element according to claim 9, wherein the step of forming the layer containing the first material is a step of applying a coating composition containing the first material on the surface to be formed. Production method. 11. The method of manufacturing an organic electroluminescent element according to claim 9, wherein the step of forming the layer containing the first material is a step of forming a film on the surface to be formed by vapor of the first material. . 13. The organic electric field according to claim 10, wherein the step of forming the layer containing the second material is a step of applying a coating composition containing the second material on the surface to be formed. Manufacturing method of light emitting element. 11. The step of forming a layer containing the first material and the second material is a step of applying a coating composition containing the first material and the second material on the surface to be formed. The manufacturing method of the organic electroluminescent element of description.

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