JP6969118B2 - Triazine compound and organic electroluminescent device containing it - Google Patents

Description

The present invention is a triazine compound useful as a constituent component of an organic electric field light emitting element, more specifically, a triazine compound characterized by having a pyridyl group in which an alkyl group is substituted in the molecule, and an organic electric field light emitting element containing the triazine compound. It is about.

In an organic electroluminescent element, a light emitting layer containing a light emitting material is sandwiched between a hole transport layer and an electron transport layer, an anode and a cathode are attached to the outside thereof, and holes and electrons injected into the light emitting layer are recombined. It is an element that utilizes the emission of light (fluorescence or phosphorescence) when the generated excitators are deactivated, and is applied not only to small displays but also to large televisions and lighting. The hole transport layer is divided into a hole transport layer and a hole injection layer, the light emitting layer is divided into an electron block layer, a light emitting layer and a hole block layer, and the electron transport layer is divided into an electron transport layer and an electron injection layer. It may be configured. Further, as the carrier transport layer (electron transport layer or hole transport layer) of the organic electroluminescent element, a co-deposited film doped with a metal, an organic metal compound or another organic compound may be used.

Conventional organic electroluminescent devices have a higher drive voltage, lower light emission brightness and light emission efficiency, and a significantly shorter device life than inorganic light emitting diodes, and have not been put into practical use in a wide range of fields. Recent organic electroluminescent devices have gradually improved the above-mentioned drawbacks, and have begun to be put into practical use mainly for mobile applications. However, performance improvement is indispensable for further expansion of applications, and materials having better low voltage characteristics, high emission efficiency characteristics, and long life characteristics are required.

Examples of the material for the organic electroluminescent device include the triazine compound disclosed in Patent Document 1. However, further improvements have been required in terms of improving the luminous efficiency and the long-life characteristics.

Japanese Unexamined Patent Publication No. 2011-063584

An object of the present invention is to provide a specific triazine compound that significantly improves the driving voltage and luminous efficiency of an organic electroluminescent element as compared with a conventionally known triazine compound. Another object of the present invention is to provide a material for an organic electroluminescent element, which is made of the specific triazine compound and has excellent driving voltage and luminous efficiency.

As a result of diligent studies to solve the above problems, the present inventors have obtained an electron of a triazine compound represented by the following general formula (1), which has a phenyl group substituted with an alkyl group. It has been found that the organic electroluminescent element used as the transport layer exhibits remarkably lower drive voltage and higher emission efficiency as compared with the case of using a conventionally known material, and has completed the present invention.

That is, the present invention relates to a triazine compound represented by the following general formula (1) (hereinafter referred to as triazine compound (1)) and an organic electroluminescent device containing the triazine compound (hereinafter referred to as triazine compound (1)).

(In the general formula (1), Ar ¹ represents the same group and is substituted with a phenyl group, a naphthyl group, or a biphenyl group (these groups are substituted with a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms. Ar ² is substituted with a polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms (the group is a phenyl group or a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms). R represents a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms. X ¹ , X ² and X ³ are independent nitrogen atoms or C, respectively. -H, ^one of X 1, X ² and X ³ represents a nitrogen atom, and the other two represent CH).

The triazine compound of the present invention can provide an organic electroluminescent element which is remarkably superior in luminous efficiency and long life characteristics as compared with a conventionally known triazine compound when used as an electron transport layer.

Hereinafter, the present invention will be described in detail.

The present invention relates to the triazine compound represented by the general formula (1).

In the triazine compound represented by the general formula (1), Ar ¹ represents the same group, and is a phenyl group, a naphthyl group, or a biphenyl group (these substituents are linear, branched, or cyclic groups having 1 to 4 carbon atoms. It may be substituted with an alkyl group.). The naphthyl group is not particularly limited, and examples thereof include a 1-naphthyl group and a 2-naphthyl group. Of these, the 1-naphthyl group is preferable because the performance of the organic electroluminescent device is excellent. The biphenyl group is not particularly limited, but for example, 1,1'-biphenyl-2-yl group, 1,1'-biphenyl-3-yl group, 1,1'-biphenyl-4. -Il group is mentioned. Of these, the 1,1'-biphenyl-3-yl group is preferable because the performance of the organic electroluminescent device is excellent. The linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms is not particularly limited, and is, for example, a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, or a 1-butyl group. 2-Butyl group, t-butyl group and the like can be mentioned. Of these, a methyl group is preferable because it is excellent in the performance of the organic electroluminescent device.

That is, Ar ¹ represents the same group in that it is excellent in the life of the organic electric field light emitting element, and is preferably an unsubstituted phenyl group, an unsubstituted naphthyl group, and an unsubstituted biphenylyl group, and the same group is used. It is more preferably a phenyl group, a 1-naphthyl group, or a 1,1'-biphenyl-3-yl group, and it represents the same group in that it is easy to synthesize, and it is further preferable to be a phenyl group. ..

In the triazine compound represented by the general formula (1), Ar ² is a polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms (the group is a phenyl group or a linear, branched or cyclic alkyl having 1 to 4 carbon atoms). It may be substituted with a group.). The alkyl group having 1 to 4 carbon atoms is not particularly limited, but is, for example, a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, or t. -Butyl group and the like can be mentioned. Of these, a methyl group is preferable because it is excellent in the performance of the organic electroluminescent device. The polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms is not particularly limited, and for example, a naphthyl group, a phenanthryl group, an anthryl group, a pyrenyl group, a triphenylenyl group, or a fluoranthenyl group can be used. Specific examples thereof include 1-naphthyl group, 2-naphthyl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthril group, 1-anthril group, 2-anthryl group, 9-anthryl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 1-triphenylenyl group, 2-triphenylenyl group, 1-fluoranthenyl group, 2-fluoranthenyl group, 3 Preferred examples include −fluoranthenyl group, 7-fluoranthenyl group, 8-fluorantenyl group, etc., with 2-phenanthryl group, 9-phenanthryl group, 2-anthryl group, or 9-anthryl group being more preferred. A preferred example is given.

Ar ² is preferably an unsubstituted polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms in terms of excellent organic field light emitting element performance, and is preferably a naphthyl group, a phenanthryl group, anthryl group, pyrenyl group, or triphenylenyl. More preferably, it is a group or a fluoranthenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthril group, a 9-phenanthril group, 1 -Anthryl group, 2-anthryl group, 9-anthryl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 1-triphenylenyl group, 2-triphenylenyl group, 1-fluoranthenyl group, 2-fluoran More preferably, it is a tenyl group, a 3-fluoranthenyl group, a 7-fluoranthenyl group, or an 8-fluoranthenyl group, a 2-phenanthryl group, a 9-phenanthril group, a 2-anthryl group, or a 9-anthryl group. It is more preferable that it is a group.

In the triazine compound represented by the general formula (1), R represents a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms. The linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms is not particularly limited, and is, for example, a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, or a 1-butyl group. 2-Butyl group, t-butyl group and the like can be mentioned. Of these, a methyl group is preferable because it is easy to synthesize.

In the triazine compound represented by the general formula (1), X ¹ , X ² and X ³ each independently represent a nitrogen atom or CH, and any one of ^{X 1} , X ² and X ^{3 is used.} It represents a nitrogen atom and the other two represent CH. ^{Of these, X 3} represents CH, X ¹ and X ² represent nitrogen atoms or CH, and any one of ^{X 1} or X ² represents a nitrogen atom in that the performance of the organic electroluminescent device is excellent. It is preferable that the remaining one represents CH.

Specific examples of the triazine compound represented by the general formula (1) include the following (A-1) to (A-27), but the present invention is not limited thereto.

The triazine compound represented by the general formula (1) of the present application is produced according to a generally known method using a generally known compound (for example, disclosed in JP-A-2008-280330), a reagent, and a generally known method. be able to.

The triazine compound represented by the general formula (1) of the present application is not particularly limited, but can be used, for example, as a material for an organic electroluminescent element, and more preferably an electron injection material or an electron of the organic electroluminescent element. It can be used as a transport material or a light emitting material.

Hereinafter, the organic electroluminescent device of the present invention will be described.

In a broad sense, the light emitting layer in an organic electroluminescent device refers to a layer that emits light when an electric current is passed through an electrode consisting of a cathode and an anode. Specifically, it refers to a layer containing a fluorescent compound that emits light when an electric current is passed through an electrode consisting of a cathode and an anode. Usually, an organic electroluminescent device has a structure in which a light emitting layer is sandwiched between a pair of electrodes.

The organic electroluminescent element of the present invention has a hole transport layer, an electron transport layer, an anode buffer layer, a cathode buffer layer and the like in addition to a light emitting layer, if necessary, and has a structure sandwiched between a cathode and an anode. Specifically, the structure shown below can be mentioned.
(I) anode / light emitting layer / cathode (ii) anode / hole transport layer / light emitting layer / cathode (iii) anode / light emitting layer / electron transport layer / cathode (iv) anode / hole transport layer / light emitting layer / electron Transport layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode A conventionally known light emitting material is used for the light emitting layer in the organic electroluminescent element of the present invention. be able to. As a method for forming the light emitting layer, there is a method for forming a thin film by a known method such as a thin film deposition method, a spin coating method, a casting method, or an LB method.

Further, this light emitting layer can be obtained by dissolving a light emitting material together with a binder such as a resin in a solvent to form a solution, and then applying this to a thin film by a spin coating method or the like.

The film thickness of the light emitting layer thus formed is not particularly limited and may be appropriately selected depending on the situation, but is usually in the range of 5 nm to 5 μm.

Next, other layers such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer that are combined with a light emitting layer to form an organic electroluminescent device will be described.

The hole injection layer and the hole transport layer have a function of transmitting holes injected from the anode to the light emitting layer, and the hole injection layer and the hole transport layer are interposed between the anode and the light emitting layer. As a result, many holes are injected into the light emitting layer at a lower electric field.

Further, the electrons injected from the cathode and transported from the electron injection layer and / or the electron transport layer to the light emitting layer are holes due to the electron barrier existing at the interface between the light emitting layer and the hole injection layer or the hole transport layer. The element is accumulated at the interface in the light emitting layer without leaking to the injection layer or the hole transport layer, and is an element having excellent light emitting performance such as improved light emitting efficiency.

The hole injection material and the hole transport material have any of hole injection or transport and electron barrier properties, and may be either an organic substance or an inorganic substance. Examples of the hole injecting material and the hole transporting material include triazole derivative, oxadiazole derivative, imidazole derivative, polyarylalkane derivative, pyrazoline derivative and pyrazolone derivative, phenylenediamine derivative, arylamine derivative, amino-substituted calcon derivative and oxazole. Examples thereof include derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilben derivatives, silazane derivatives, aniline-based copolymers, and conductive polymer oligomers, especially thiophene oligomers. As the hole injecting material and the hole transporting material, the above-mentioned ones can be used, but porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds, particularly aromatic tertiary amine compounds may be used. preferable.

Typical examples of the above aromatic tertiary amine compound and styrylamine compound are N, N, N', N'-tetraphenyl-4,4'-diaminophenyl, N, N'-diphenyl-N, N'. -Bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine (TPD), 2,2-bis (4-di-p-tolylaminophenyl) propane, 1,1- Bis (4-di-p-tolylaminophenyl) cyclohexane, N, N, N', N'-tetra-p-tolyl-4,4'-diaminobiphenyl, 1,1-bis (4-di-p-) Trillaminophenyl) -4-phenylcyclohexane, bis (4-dimethylamino-2-methylphenyl) phenylmethane, bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N, N '-Di (4-methoxyphenyl) -4,4'-diaminobiphenyl, N, N, N', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis (diphenylamino) Audriphenyl, N, N, N-tri (p-tolyl) amine, 4- (di-p-tolylamino) -4'-[4- (di-p-tolylamino) styryl] Stilben, 4-N, N- Diphenylamino- (2-diphenylvinyl) benzene, 3-methoxy-4'-N, N-diphenylaminostillbenzene, N-phenylcarbazole, 4,4'-bis [N- (1-naphthyl) -N-phenyl Examples thereof include amino] biphenyl (NPD), 4,4', 4''-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA).

Inorganic compounds such as p-type-Si and p-type-SiC can also be used as hole injection materials and hole transport materials. The hole injection layer and the hole transport layer are formed by thinning the hole injection material and the hole transport material by a known method such as a vacuum vapor deposition method, a spin coating method, a casting method, or an LB method. Can be formed. The film thickness of the hole injection layer and the hole transport layer is not particularly limited, but is usually about 5 nm to 5 μm. The hole injection layer and the hole transport layer may have a one-layer structure composed of one or more of the above materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.

In the organic electroluminescent device of the present invention, the electron transport layer contains the triazine compound represented by the above general formula (1).

The electron transport layer can be formed by forming a triazine compound represented by the above general formula (1) by a known thin film forming method such as a vacuum vapor deposition method, a spin coating method, a casting method, or an LB method. can. The film thickness of the electron transport layer is not particularly limited, but is usually selected in the range of 5 nm to 5 μm. Further, the electron transport layer may contain a triazine compound represented by the general formula (1) and may contain a conventionally known electron transport material, or may have a one-layer structure including one or more kinds. Alternatively, it may have a laminated structure composed of a plurality of layers having the same composition or a different composition.

Further, in the present invention, the light emitting material is not limited to the light emitting layer, and one kind may be contained in the hole transport layer or the electron transport layer adjacent to the light emitting layer, whereby the organic electroluminescent element may be further contained. The luminous efficiency of the

The substrate preferably used for the organic electroluminescent device of the present invention is not particularly limited in the types such as glass and plastic, and is not particularly limited as long as it is transparent. Examples of the substrate preferably used for the organic electroluminescent element of the present invention include glass, quartz, and a light-transmitting plastic film.

Examples of the light-transmitting plastic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyetherimide, polyether ether ketone, polyphenylene sulfide, polyarylate, polyimide, and polycarbonate (PC). , A film composed of cellulose triacetate (TAC), cellulose acetate propionate (CAP) and the like.

A suitable example for manufacturing the organic electroluminescent device of the present invention will be described. As an example, a method for manufacturing an organic electroluminescent device including the anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described.

First, a thin film made of a desired electrode substance, for example, an anode substance, is formed on a suitable substrate by a method such as thin film deposition or sputtering so as to have a film thickness in the range of 1 μm or less, preferably 10 to 200 nm. Make an anode. Next, a thin film composed of a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer / electron injection layer, which are element materials, is formed on this.

A buffer layer (electrode interface layer) may be present between the anode and the light emitting layer or the hole injection layer, and between the cathode and the light emitting layer or the electron injection layer.

Further, in addition to the above basic constituent layer, a layer having other functions may be laminated, if necessary, and a functional layer such as a hole block layer or an electron block layer may be provided.

Next, the electrode of the organic electroluminescent device of the present invention will be described. As the anode in the organic electroluminescent element, a metal having a large work function (4 eV or more), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is preferably used. Specific examples of such an electrode material include metals such as Au and conductive transparent materials such as _{CuI, indium tin oxide (ITO), SnO 2, and ZnO.}

The anode may form a thin film of these electrode materials by a method such as thin film deposition or sputtering to form a pattern having a desired shape by a photolithography method, or a pattern may be formed through a mask having a desired shape during vapor deposition or sputtering. May be formed.

On the other hand, as the cathode, a metal having a small work function (4 eV or less) (referred to as an electron-injectable metal), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is preferably used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O). ₃ ) Examples include mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the viewpoint of electron injectability and durability against oxidation, a mixture of an electron injectable metal and a second metal which is a stable metal having a larger work function value than this, for example, magnesium / silver mixture, magnesium. / Aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, lithium / aluminum mixture and the like are suitable. The cathode can be produced by forming a thin film of these electrode materials by a method such as thin film deposition or sputtering.

As described above, a thin film made of a desired electrode material, for example, an anode material, is formed on a suitable substrate by a method such as thin film deposition or sputtering so as to have a film thickness in the range of 1 μm or less, preferably 10 to 200 nm. After forming an anode, each layer thin film composed of a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer / electron injection layer is formed on the anode as described above, and then for a cathode. A thin film made of a substance is formed to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, by a method such as vapor deposition or sputtering, and a cathode is provided to obtain a desired organic electric field light emitting element.

The organic electroluminescent element of the present invention may be used as a kind of lamp such as for lighting or an exposure light source, a projection device of a type for projecting an image, or a display of a type for directly visually recognizing a still image or a moving image. It may be used as a device (display). When used as a display device for video reproduction, the drive method may be either a simple matrix (passive matrix) method or an active matrix method. Further, a full-color display device can be manufactured by using two or more kinds of organic electroluminescent devices of the present invention having different emission colors.

It is sectional drawing of the single layer element produced in an Example.

1. 1. Glass substrate with ITO transparent electrode 2. Hole injection layer 3. Charge generation layer 4. Hole transport layer 5. Light emitting layer 6. Electron transport layer 7. Cathode layer

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not construed as being limited to these examples.

The FDMS measurement was performed using M-80B manufactured by Hitachi, Ltd.

^{1 1} H-NMR measurement was performed using Gemini200 (manufactured by Varian).

The emission characteristics of the organic electroluminescent element were evaluated using a luminance meter of LUMINANCEMEMETER (BM-9) (manufactured by TOPCON) by applying a direct current to the manufactured element at room temperature.

Synthesis Example-1

2- (3-bromo-5-chlorophenyl) -4,6-diphenyl-1,3,5-triazine (70.0 g, 0.166 mol), 9-phenanthrene boronic acid (38.6 g, 0) under an argon stream. .174 mol) and tetrakis (triphenylphosphine) palladium (3.83 g, 3.31 mmol) were suspended in tetrahydrofuran (1000 mL), and 4.0 M-sodium hydroxide aqueous solution (124 mL, 0. 497 mol) was added dropwise. The resulting mixture was stirred at 70 ° C. for 24 hours. After allowing to cool, water (550 mL) was added, the precipitated solid was filtered off, and the solid was washed with water, methanol, and hexane. By recrystallization (toluene), a white solid (yield 78) of 2- [3-chloro-5- (9-phenanthryl) phenyl] -4,6-diphenyl-1,3,5-triazine, which is a reaction intermediate, 9.9 g, yield 92%) was obtained.

Synthesis Example-2

2- [3-Chloro-5 (9-phenanthril) phenyl] -4,6-diphenyl-1,3,5-triazine (5.20 g, 10 mmol) obtained in Synthesis Example-1 under an argon stream. Bispinacolat diboron (3.81 g, 15 mmol), palladium acetate (22.5 mg, 0.10 mmol), 2-dicyclohexylphosphino-2', 4', 6'-triisopropylbiphenyl (95.4 mg, 0. 20 mmol) and potassium acetate (2.95 g, 30 mmol) were suspended in 1,4-dioxane (200 mL) and stirred at 100 ° C. for 4 hours. After allowing to cool, the precipitate component was removed by filtration. Chloroform (200 mL) and water (100 mL) were added and stirred, and then the aqueous layer and the organic layer were separated. Further, the aqueous layer was extracted 3 times with chloroform (50 mL) and combined with the organic layer. The low boiling point component was concentrated under reduced pressure from the organic layer and dried to dryness to obtain a crude product. Hexane was added, and the mixture was stirred and suspended while cooling to 0 ° C., and the obtained solid was collected by filtration. By drying the obtained solid under reduced pressure, 2- [3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -5- (9-phenanthril) phenyl] A milky white powder of -4,6-diphenyl-1,3,5-triazine (yield 6.07 g, yield 99%) was obtained.

^{1 1} H-NMR (CDCl ₃ ) δ (ppm): 1.43 (s, 12H), 7.51-7.75 (m, 10H), 7.82 (s, 1H), 7.89-7. 98 (m, 2H), 8.23 (brs, 1H), 8.75-8.81 (m, 5H), 8.83 (brd, J = 8.2Hz, 1H), 9.01 (brs, 1H), 9.24 (brs, 1H).
Synthesis Example-1

2- [3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -5- (9-phenanthril) phenyl obtained in Synthesis Example-2 under a nitrogen stream. ] -4,6-diphenyl-1,3,5-triazine (3.00 g, 4.91 mmol), 2-bromo-3-methylpyridine (1.02 g, 5.40 mmol), and tetrakis (triphenylphosphine). Palladium (0.170 g, 0.147 mmol) was suspended in tetrahydrofuran (25 mL), and a 2.0 M-potassium phosphate aqueous solution (7.36 mL, 14.7 mol) was added dropwise to the obtained suspension. The resulting mixture was stirred at 65 ° C. for 28 hours. The obtained reaction solution was allowed to cool to room temperature, and the precipitate was collected by filtration. The precipitate collected by filtration was washed successively with pure water, methanol and hexane to obtain a gray powder. The obtained gray powder was purified by recrystallization from toluene, and the desired product was 2- [3- (3-methyl-2-pyridyl) -5- (9-phenanthryl) phenyl] -4,6-diphenyl. A gray powder of -1,3,5-triazine (Compound A-13) (yield 1.13 g, yield 40%, LC purity 99.57%) was obtained.

FDMS: 576
Synthesis Example-2

2- [3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -5- (9-phenanthril) phenyl obtained in Synthesis Example-2 under a nitrogen stream. ] -4,6-diphenyl-1,3,5-triazine (3.00 g, 4.91 mmol), 3-bromo-4-methylpyridine (1.02 g, 5.40 mmol), and tetrakis (triphenylphosphine). Palladium (0.170 g, 0.147 mmol) was suspended in tetrahydrofuran (25 mL), and a 2.0 M-potassium phosphate aqueous solution (7.36 mL, 14.7 mol) was added dropwise to the obtained suspension. The resulting mixture was stirred at 65 ° C. for 5 hours. The obtained reaction solution was allowed to cool to room temperature, and the precipitate was collected by filtration. The precipitate collected by filtration was washed successively with pure water, methanol and hexane to obtain a gray powder. The obtained gray powder was purified by recrystallization from toluene, and the desired product was 2- [3- (4-methyl-3-pyridyl) -5- (9-phenanthryl) phenyl] -4,6-diphenyl. A gray powder of -1,3,5-triazine (Compound A-14) (yield 1.31 g, yield 47%, LC purity 99.66%) was obtained.

FDMS: 576
Synthesis example-3

2- (3-bromo-5-chlorophenyl) -4,6-diphenyl-1,3,5-triazine (30.0 g, 71.0 mmol), 9-anthracene boronic acid (18.9 g, 85) under nitrogen stream. .2 mol) and tetrakis (triphenylphosphine) palladium (0.820 g, 0.710 mmol) were suspended in tetrahydrofuran (300 mL), and a 4.0 M-sodium hydroxide aqueous solution (53.2 mL,) was added to the obtained suspension. 213 mmol) was added dropwise. The resulting mixture was stirred at 70 ° C. for 5 hours. After allowing to cool, water (200 mL) was added, the precipitated solid was filtered off, and the solid was washed with water and methanol. By recrystallizing the obtained solid (toluene), the target product 2- [5- (9-anthryl) -3-chlorophenyl] -4,6-diphenyl-1,3,5-triazine is light yellow. A solid (yield 32.7 g, yield 89%) was obtained.

Synthesis example-4

2- [5- (9-anthryl) -3-chlorophenyl] -4,6-diphenyl-1,3,5-triazine (15.0 g, 28.9 mmol) obtained in Synthesis Example-3 under an argon stream. , Bispinacolat diboron (8.79 g, 34.6 mmol), Palladium acetate (130 mg, 0.577 mmol), 2-dicyclohexylphosphino-2', 4', 6'-triisopropylbiphenyl (550 mg, 1.15 mmol) ) And potassium acetate (8.50 g, 86.6 mmol) were suspended in toluene (300 mL), and the mixture was stirred at 100 ° C. for 6 hours. After allowing to cool, 200 mL of toluene was added to the reaction solution, and then the precipitate component was removed by filtration. The low boiling point component was concentrated under reduced pressure from the obtained organic layer and dried to dryness to obtain a pale yellow solid. By washing the pale yellow solid with methanol, the target product is 2- [5- (9-anthril) -3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl). ) Phenyl] -4,6-diphenyl-1,3,5-triazine light yellow powder (yield 17.1 g, yield 97%) was obtained.

Synthesis Example-3

2- [5- (9-anthril) -3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) phenyl obtained in Synthesis Example-4 under a nitrogen stream ] -4,6-diphenyl-1,3,5-triazine (3.00 g, 4.91 mmol), 3-bromo-4-methylpyridine (1.02 g, 5.40 mmol), palladium acetate (33.0 mg,) 0.147 mmol), 2-dicyclohexylphosphino-2', 4', 6'-triisopropylbiphenyl (140 mg, 0.294 mmol) was suspended in tetrahydrofuran (50 mL) and 2.0 M- was added to the obtained suspension. An aqueous solution of potassium phosphate (7.36 mL, 14.7 mol) was added dropwise. The resulting mixture was stirred at 65 ° C. for 24 hours. The obtained reaction solution was concentrated under reduced pressure, and the precipitate was collected by filtration. The precipitate collected by filtration was washed successively with pure water and methanol to obtain a pale yellow powder. The obtained pale yellow powder was purified by recrystallization with a mixed solvent of toluene and 1-butanol, and the desired product was 2- [5- (9-anthryl) -3- (4-methyl-3-pyridyl). Phenyl] -4,6-diphenyl-1,3,5-triazine (Compound A-11) gray powder (yield 1.41 g, yield 50%, LC purity 99.32%) was obtained.

FDMS: 576
The structural formulas and abbreviations of the compounds used for device evaluation are shown below.

Element Example-1
As the substrate, a glass substrate with an ITO transparent electrode in which a 2 mm wide indium tin oxide (ITO) film (thickness 110 nm) was patterned in a stripe shape was used. This substrate was washed with isopropyl alcohol and then surface-treated by ozone ultraviolet washing. A substrate after cleaning and vacuum deposition of each layer in the vacuum deposition method to produce a light-emitting area 4 mm ² The organic electroluminescent device as shown in the sectional view of FIG. 1. Each organic material was formed into a film by a resistance heating method.

First, the glass substrate was introduced into the vacuum vapor deposition tank, and the pressure was reduced to ^{1.0 × 10 -4 Pa.}

After that, the hole injection layer 2, the charge generation layer 3, the hole transport layer 4, the light emitting layer 5, the electron transport layer 6, and the cathode layer are formed as organic compound layers on the glass substrate with the ITO transparent electrode shown in FIG. 7 were laminated in this order, and all of them were formed by vacuum vapor deposition.

As the hole injection layer 2, sublimated and purified HIL was formed into a 65 nm film at a rate of 0.15 nm / sec.

As the charge generation layer 3, a sublimated and purified HAT was formed into a 5 nm film at a rate of 0.05 nm / sec.

As the hole transport layer 4, HTL was formed into a 10 nm film at a rate of 0.15 nm / sec.

As the light emitting layer 5, EML-1 and EML-2 were formed into a film at a ratio of 95: 5 (weight ratio) at 25 nm (film formation rate 0.18 nm / sec).

The electron transport layer 6 includes 2- [3- (3-methyl-2-pyridyl) -5- (9-phenanthryl) phenyl] -4,6-diphenyl-1 synthesized in Synthesis Example-1 of the present invention. , 3,5-Triazine (Compound A-13) and Liq were formed at a ratio of 50:50 (weight ratio) at 30 nm (deposition rate 0.15 nm / sec).

Finally, a metal mask was arranged so as to be orthogonal to the ITO stripe, and the cathode layer 7 was formed into a film. The cathode layer 7 is made of silver / magnesium (weight ratio 1/10) and silver in this order at 80 nm (deposition rate 0.5 nm / sec) and 20 nm (deposition rate 0.2 nm / sec), respectively. It has a two-layer structure.

Each film thickness was measured with a stylus type film thickness measuring meter (DEKTAK).

Further, this element was sealed in a nitrogen atmosphere glove box having an oxygen and water concentration of 1 ppm or less. For sealing, a glass sealing cap and the film-forming substrate epoxy type ultraviolet curable resin (manufactured by Nagase ChemteX Corporation) were used.

Element Example-2
In the device Example-1, 2- [3- (4-methyl-3-pyridyl) -5- (9-phenanthryl) phenyl] -4,6-diphenyl synthesized in the electron transport layer 6 in Synthesis Example-2. An organic electroluminescent device was prepared in the same manner as in Device Example-1 except that -1,3,5-triazine (Compound A-14) was used.

Element reference example-1
In the device Example-1, 4,6-diphenyl-2- [5- (9-phenanthril) -3, which is a compound described in Example-6 of JP2011-063584A, in the electron transport layer 6 An organic electroluminescent device was prepared in the same manner as in Device Example-1 except that − (3-pyridyl) phenyl] -1,3,5-triazine (compound ETL-1) was used.

A direct current was applied to the produced organic electroluminescent element, and the emission characteristics were evaluated using a luminance meter of LUMINANCE METER (BM-9) manufactured by TOPCON. As the light emission characteristics, the voltage (V) and the current efficiency (cd / A) when a current density of 10 mA / cm ^{2 was passed were measured, and the element life during continuous lighting was measured.} Note that the element life, to the initial luminance was measured continuously luminance decay time at the time of lighting when driven at 800 cd / ^{m 2} and luminance (cd / ^{m 2)} up to reduce 25% (luminance initial 75 percent reached ) Was measured, and then expressed as a relative value when the time required for the ^{luminance (cd / m 2} ) to decrease by 25% in Reference Example 1 of the element was set to 100. The results are shown below.

From Table 1, it was found that the organic electroluminescent device using the azine compound of the present invention is remarkably superior in driving voltage and luminous efficiency as compared with the reference example.

The present invention provides a triazine compound having a novel structure that enables low voltage drive, high efficiency and long life of the device by using it as an electron transport layer of an organic electroluminescent device, and further provides a low voltage using the compound. It provides an organic electroluminescent element provided with voltage conversion.

Claims (7)

A triazine compound represented by the general formula (1).

(In the general formula (1), Ar ¹ represents the same group and represents an unsubstituted phenyl group or a unsubstituted biphenyl group . Ar ² represents an unsubstituted 9-phenanthril group . ^.X 1, and ^{X 2} representing a methyl group, have Zureka one represents a nitrogen atom, represents. ^{X 3} and the other is C-H, representing the C-H.) The triazine compound according to claim 1, wherein Ar ¹ represents the same group and is an unsubstituted phenyl group. A triazine compound represented by the following formula.

A triazine compound represented by the following formula.

A material for an organic electroluminescent device, which comprises the triazine compound according to any one of claims 1 to 4. An electron transport material for an organic electroluminescent device, which comprises the triazine compound according to any one of claims 1 to 4. An organic electroluminescent device comprising the triazine compound according to any one of claims 1 to 4.

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