JP2017178931A - Triazine compound and organic electroluminescent element containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a triazine compound that realizes better drive voltage and luminous efficacy of an organic electroluminescent element than conventional triazine compounds; and an organic electroluminescent element containing the compound.SOLUTION: The invention provides a triazine compound represented by general formula (1), and an organic electroluminescent element containing the same as a constituent.SELECTED DRAWING: None

Description

  The present invention relates to a triazine compound useful as a component of an organic electroluminescent device, more specifically a triazine compound having a pyridyl group substituted with an alkyl group in the molecule, and an organic electroluminescent device containing the triazine compound It is about.

  An organic electroluminescent element is formed by sandwiching a light-emitting layer containing a light-emitting material between a hole transport layer and an electron transport layer, and further attaching an anode and a cathode to the outside, and recombination of holes and electrons injected into the light-emitting layer. It is an element that utilizes light emission (fluorescence or phosphorescence) when the excitons that are generated 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 blocking layer, a light emitting layer and a hole blocking layer, and the electron transport layer is divided into an electron transport layer and an electron injection layer. May be configured. In some cases, a co-deposited film doped with a metal, an organometallic compound, or another organic compound may be used as the carrier transport layer (electron transport layer or hole transport layer) of the organic electroluminescence device.

  Conventional organic electroluminescent elements have higher driving voltage than inorganic light-emitting diodes, low luminance and luminous efficiency, and extremely low element lifetime, so that they have not been put to practical use in a wide range of fields. Recent organic electroluminescence devices are gradually improved with the above-mentioned drawbacks, and practical application has begun mainly for mobile applications. However, in order to further expand applications, performance improvement is essential, and materials with better low voltage characteristics, high light emission efficiency characteristics, and long life characteristics are required.

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

JP 2011-063584 A

  An object of the present invention is to provide a specific triazine compound that remarkably improves the driving voltage and the light emission efficiency of an organic electroluminescent device as compared with conventionally known triazine compounds. Another object of the present invention is to provide a material for an organic electroluminescence device excellent in driving voltage and light emission efficiency using the specific triazine compound.

  As a result of intensive studies to solve the above problems, the present inventors have obtained a triazine compound represented by the following general formula (1), which has a phenyl group substituted with an alkyl group, as an electron. It has been found that the organic electroluminescence device used as the transport layer exhibits significantly lower driving voltage and higher light emission efficiency than when a conventionally known material is used, and the present invention has been completed.

  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 electroluminescence device containing the same.

(In the general formula (1), Ar ¹ represents the same group, and 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 represents a polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms (this group is substituted with 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, and X ¹ , X ^2, and X ³ each independently represent a nitrogen atom or C -H is represented, and any one of X ¹ , X ² and X ³ represents a nitrogen atom, and the remaining two represent C—H.

  When used as an electron transport layer, the triazine compound of the present invention can provide an organic electroluminescence device that is remarkably excellent in luminous efficiency and long life characteristics as compared with a conventionally known triazine compound.

  Hereinafter, the present invention will be described in detail.

  The present invention relates to a 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 a phenyl group, a naphthyl group, or a biphenyl group (these substituents are linear, branched, or cyclic having 1 to 4 carbon atoms). Which may be substituted with an alkyl group). Although it does not specifically limit as said naphthyl group, For example, 1-naphthyl group and 2-naphthyl group are mentioned. Among these, a 1-naphthyl group is preferable in terms of excellent organic electroluminescence device performance. In addition, the biphenyl group is not particularly limited, and examples thereof include 1,1′-biphenyl-2-yl group, 1,1′-biphenyl-3-yl group, and 1,1′-biphenyl-4. -An yl group is mentioned. Of these, a 1,1′-biphenyl-3-yl group is preferable in terms of excellent organic electroluminescence device performance. The linear, branched or cyclic alkyl group having 1 to 4 carbon atoms is not particularly limited, and examples thereof include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, A 2-butyl group, a t-butyl group, etc. are mentioned. Among these, a methyl group is preferable in that the performance of the organic electroluminescent element is excellent.

That is, Ar ¹ represents the same group in terms of excellent lifetime of the organic electroluminescence device, and is preferably an unsubstituted phenyl group, an unsubstituted naphthyl group, or an unsubstituted biphenylyl group. More preferably a phenyl group, a 1-naphthyl group, or a 1,1′-biphenyl-3-yl group, and from the viewpoint of easy synthesis, it represents the same group, and more preferably 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 (this group is a phenyl group or a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms). Which may be substituted with a group). The alkyl group having 1 to 4 carbon atoms is not particularly limited, and examples thereof include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, and t. -A butyl group etc. are mentioned. Among these, a methyl group is preferable in that the performance of the organic electroluminescent element is excellent. The polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms is not particularly limited, and examples thereof include a naphthyl group, a phenanthryl group, an anthryl group, a pyrenyl group, a triphenylenyl group, and a fluoranthenyl group. And more specific examples include 1-naphthyl group, 2-naphthyl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl 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-fluoranthenyl group, 3 Preferred examples include -fluoranthenyl group, 7-fluoranthenyl group, and 8-fluoranthenyl group. 2-phenanthryl group, 9-phenanthryl group, 2-anthryl group, or a 9-anthryl group More preferred examples.

Ar ² is preferably an unsubstituted polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms from the viewpoint of excellent organic electroluminescence device performance, and includes a naphthyl group, a phenanthryl group, an anthryl group, a pyrenyl group, and a triphenylenyl 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-phenanthryl group, a 9-phenanthryl 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-fluorane It is a tenenyl group, a 3-fluoranthenyl group, a 7-fluoranthenyl group, or an 8-fluoranthenyl group. Are more preferable, and a 2-phenanthryl group, a 9-phenanthryl group, a 2-anthryl group, or a 9-anthryl group is more preferable.

  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 examples thereof include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, A 2-butyl group, a t-butyl group, etc. are mentioned. Among these, a methyl group is preferable in terms of easy synthesis.

In the triazine compound represented by the general formula (1), X ¹ , X ² and X ³ each independently represent a nitrogen atom or C—H, and any one of X ¹ , X ² and X ³ is Represents a nitrogen atom and the remaining two represent C—H. Among these, X ³ represents C—H, X ¹ and X ² represent a nitrogen atom or C—H, and any one of X ¹ or X ² represents a nitrogen atom in that the organic electroluminescent element performance is excellent. And the remaining one preferably represents C—H.

  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. For example, it can be used as a material for an organic electroluminescent element, and more preferably, an electron injection material for an organic electroluminescent element, an electron It can be used as a transport material or a light emitting material.

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

  In a broad sense, the light emitting layer in an organic electroluminescent element refers to a layer that emits light when a current is passed through an electrode composed 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 composed of a cathode and an anode. Usually, an organic electroluminescent element has a structure in which a light emitting layer is sandwiched between a pair of electrodes.

The organic electroluminescent device of the present invention has a hole transport layer, an electron transport layer, an anode buffer layer, a cathode buffer layer, etc. in addition to the light emitting layer as required, and has a structure sandwiched between a cathode and an anode. Specific examples include the structures shown below.
(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 For the light emitting layer in the organic electroluminescent device of the present invention, a conventionally known light emitting material is used. be able to. As a method for forming the light emitting layer, for example, there is a method of forming a thin film by a known method such as a vapor deposition method, a spin coating method, a casting method, or an LB method.

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

  There is no restriction | limiting in particular about the film thickness of the light emitting layer formed in this way, Although it can select suitably according to a condition, Usually, it is the range of 5 nm-5 micrometers.

  Next, other layers constituting the organic electroluminescence device in combination with the light emitting layer, such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer, will be described.

  The hole injection layer and the hole transport layer have a function of transmitting the 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. Thus, many holes are injected into the light emitting layer with a lower electric field.

  In addition, electrons injected from the cathode and transported from the electron injection layer and / or the electron transport layer to the light-emitting layer are generated by the electron barrier existing at the interface between the light-emitting layer and the hole injection layer or the hole transport layer. It accumulates at the interface in the light emitting layer without leaking into the injection layer or the hole transport layer, resulting in an element with excellent light emitting performance such as improved luminous efficiency.

  The hole injection material and the hole transport material have any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. Examples of the hole injection material and hole transport material include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazoles. Derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers. As the hole injecting material and the hole transporting material, those described above can be used, and porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds, particularly aromatic tertiary amine compounds can be used. preferable.

  Representative examples of the aromatic tertiary amine compound and styrylamine compound include 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- Tolylaminophenyl) -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) quadri Phenyl, N, N, N-tri (p-tolyl) amine, 4- (di-p-tolylamino) -4 ′-[4- (di-p-tolylamino) styryl] stilbene, 4-N, N-diphenyl Amino- (2-diphenylvinyl) benzene, 3-methoxy-4′-N, N-diphenylaminostilbenzene, N-phenylcarbazole, 4,4′-bis [N- (1-naphthyl) -N-phenylamino ] Biphenyl (NPD), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) and the like. That.

  In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material. 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 deposition method, a spin coating method, a casting method, or an LB method. Can be formed. Although there is no restriction | limiting in particular about the film thickness of a positive hole injection layer and a positive hole transport layer, Usually, it is about 5 nm-5 micrometers. The hole injection layer and hole transport layer may have a single layer structure composed of one or more of the above materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

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

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

  In the present invention, the light emitting material is not limited to the light emitting layer, but may be contained in the hole transport layer or the electron transport layer adjacent to the light emitting layer. The luminous efficiency can be increased.

  The substrate that is preferably used in the organic electroluminescence device of the present invention is not particularly limited in the type of glass, plastic, and the like, and is not particularly limited as long as it is transparent. Examples of the substrate preferably used in the organic electroluminescence device of the present invention include glass, quartz, and a light transmissive plastic film.

  Examples of the light transmissive plastic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, and polycarbonate (PC). And a film made of cellulose triacetate (TAC), cellulose acetate propionate (CAP), or the like.

  A suitable example for producing the organic electroluminescent element of the present invention will be described. As an example, a method for producing an organic electroluminescent element composed of 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 material, for example, an anode material, is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. An anode is produced. Next, a thin film comprising a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer / electron injection layer, which is a device material, is formed thereon.

  A buffer layer (electrode interface layer) may exist 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.

  Furthermore, in addition to the basic constituent layer, a layer having other functions may be laminated as necessary. For example, a functional layer such as a hole blocking layer or an electron blocking layer may be provided.

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

  The anode may be formed by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by photolithography, or the pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering. May be formed.

On the other hand, as the cathode, those using an electrode substance of a metal having a small work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound and a mixture thereof are 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 ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this from the viewpoint of durability against electron injecting and oxidation, for example, a magnesium / silver mixture, magnesium An aluminum / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, and the like are preferable. The cathode can be produced by forming a thin film from these electrode materials by a method such as vapor 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 vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. After preparing the anode, after forming each layer thin film consisting of the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer / electron injection layer on the anode as described above, for the cathode A thin film made of a substance is formed by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably in a range of 50 to 200 nm, and a desired organic electroluminescent device is obtained.

  The organic electroluminescence device of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display). When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Moreover, it is possible to produce a full-color display device by using two or more organic electroluminescent elements of the present invention having different emission colors.

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

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

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is limited and is not interpreted at all by these Examples.

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

¹ H-NMR measurement was performed using Gemini 200 (manufactured by Varian).

  The light emission characteristics of the organic electroluminescence device were evaluated by applying a direct current to the fabricated device at room temperature and using a luminance meter of LUMINANCEMETER (BM-9) (manufactured by TOPCON).

  Synthesis Example-1

Under an argon stream, 2- (3-bromo-5-chlorophenyl) -4,6-diphenyl-1,3,5-triazine (70.0 g, 0.166 mol), 9-phenanthreneboronic acid (38.6 g, 0) 174 mol) and tetrakis (triphenylphosphine) palladium (3.83 g, 3.31 mmol) were suspended in tetrahydrofuran (1000 mL), and 4.0 M aqueous sodium hydroxide solution (124 mL, 0.001 mL) was added to the resulting suspension. 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), 2- [3-chloro-5- (9-phenanthryl) phenyl] -4,6-diphenyl-1,3,5-triazine, a white solid (yield 78), was obtained as a reaction intermediate. 0.9 g, yield 92%).

  Synthesis Example-2

  2- [3-chloro-5- (9-phenanthryl) phenyl] -4,6-diphenyl-1,3,5-triazine (5.20 g, 10 mmol) obtained in Synthesis Example 1 under an argon stream, Bispinacolato diboron (3.81 g, 15 mmol), palladium acetate (22.5 mg, 0.10 mmol), 2-dicyclohexylphosphino-2 ′, 4 ′, 6′-triisopropylbiphenyl (95.4 mg, 0.8 mmol). 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 precipitated components were 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 with chloroform (50 mL) three times and combined with the organic layer. The low boiling point component was concentrated under reduced pressure from the organic layer and dried to obtain a crude product. Hexane was added and stirred and suspended while cooling to 0 ° C., and the resulting solid was collected by filtration. The obtained solid was dried under reduced pressure to give 2- [3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -5- (9-phenanthryl) phenyl]. A milky white powder (yield 6.07 g, yield 99%) of -4,6-diphenyl-1,3,5-triazine was obtained.

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 = 8.2 Hz, 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-phenanthryl) 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 2.0 M aqueous potassium phosphate solution (7.36 mL, 14.7 mol) was added dropwise to the resulting suspension. The resulting mixture was stirred at 65 ° C. for 28 hours. The resulting 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 2- [3- (3-methyl-2-pyridyl) -5- (9-phenanthryl) phenyl] -4,6-diphenyl was obtained. A gray powder (yield 1.13 g, yield 40%, LC purity 99.57%) of -1,3,5-triazine (compound A-13) was obtained.

FDMS: 576
Synthesis Example-2

  2- [3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -5- (9-phenanthryl) 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 2.0 M aqueous potassium phosphate solution (7.36 mL, 14.7 mol) was added dropwise to the resulting suspension. The resulting mixture was stirred at 65 ° C. for 5 hours. The resulting 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 2- [3- (4-methyl-3-pyridyl) -5- (9-phenanthryl) phenyl] -4,6-diphenyl was obtained. A gray powder (yield 1.31 g, yield 47%, LC purity 99.66%) of -1,3,5-triazine (Compound A-14) was obtained.

FDMS: 576
Synthesis example-3

  Under a nitrogen stream, 2- (3-bromo-5-chlorophenyl) -4,6-diphenyl-1,3,5-triazine (30.0 g, 71.0 mmol), 9-anthraceneboronic acid (18.9 g, 85) .2 mol) and tetrakis (triphenylphosphine) palladium (0.820 g, 0.710 mmol) were suspended in tetrahydrofuran (300 mL), and 4.0 M aqueous sodium hydroxide solution (53.2 mL, 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. The obtained solid was recrystallized (toluene) to give a light yellow 2- [5- (9-anthryl) -3-chlorophenyl] -4,6-diphenyl-1,3,5-triazine, which is the target product. 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 Bispinacolatodiboron (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 stirred at 100 ° C. for 6 hours. After allowing to cool, 200 mL of toluene was added to the reaction solution, and then the precipitated components were removed by filtration. From the obtained organic layer, the low-boiling component was concentrated under reduced pressure and dried to obtain a light yellow solid. 2- [5- (9-anthryl) -3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) which is the target product by washing the pale yellow solid with methanol ) Phenyl] -4,6-diphenyl-1,3,5-triazine (yield 17.1 g, yield 97%).

  Synthesis Example-3

  2- [5- (9-anthryl) -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- A potassium phosphate aqueous solution (7.36 mL, 14.7 mol) was added dropwise. The resulting mixture was stirred at 65 ° C. for 24 hours. The resulting 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 from a mixed solvent of toluene and 1-butanol, and the desired product 2- [5- (9-anthryl) -3- (4-methyl-3-pyridyl) was obtained. A gray powder (yield 1.41 g, yield 50%, LC purity 99.32%) of phenyl] -4,6-diphenyl-1,3,5-triazine (Compound A-11) 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 on which a 2 mm wide indium-tin oxide (ITO) film (film thickness 110 nm) was patterned in a stripe shape was used. The substrate was cleaned with isopropyl alcohol and then surface treated by ozone ultraviolet cleaning. Each layer was vacuum-deposited on the cleaned substrate by a vacuum deposition method, and an organic electroluminescence device having a light-emitting area of 4 mm ² as shown in FIG. Each organic material was formed by a resistance heating method.

First, the said glass substrate was introduce | transduced in the vacuum evaporation tank and it pressure-reduced to 1.0 * 10 <^-4> Pa.

  Thereafter, a hole injection layer 2, a charge generation layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, and a cathode layer are formed as an organic compound layer on the glass substrate with an ITO transparent electrode shown by 1 in FIG. 7 were laminated in this order, and all were formed by vacuum deposition.

  As the hole injection layer 2, a sublimated HIL film having a thickness of 65 nm was formed at a rate of 0.15 nm / second.

  As the charge generation layer 3, sublimation-purified HAT was deposited to a thickness of 5 nm at a rate of 0.05 nm / second.

  As the hole transport layer 4, HTL was formed to a thickness of 10 nm at a rate of 0.15 nm / second.

  As the light emitting layer 5, EML-1 and EML-2 were formed to a thickness of 25 nm at a ratio of 95: 5 (weight ratio) (deposition rate of 0.18 nm / second).

  As the electron transport layer 6, 2- [3- (3-methyl-2-pyridyl) -5- (9-phenanthryl) phenyl] -4,6-diphenyl-1 synthesized in Synthesis Example 1 of the present invention was used. , 3,5-triazine (Compound A-13) and Liq were deposited at a ratio of 50:50 (weight ratio) to a thickness of 30 nm (deposition rate of 0.15 nm / second).

  Finally, a metal mask was arranged so as to be orthogonal to the ITO stripe, and the cathode layer 7 was formed. The cathode layer 7 is formed of silver / magnesium (weight ratio 1/10) and silver in this order at 80 nm (film formation rate 0.5 nm / second) and 20 nm (film formation rate 0.2 nm / second), respectively. And it was set as the 2 layer structure.

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

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

Element Example-2
In device example-1, 2- [3- (4-methyl-3-pyridyl) -5- (9-phenanthryl) phenyl] -4,6-diphenyl synthesized in synthesis example-2 on the electron transport layer 6 An organic electroluminescent device was produced 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 device example-1, 4,6-diphenyl-2- [5- (9-phenanthryl) -3, which is the compound described in Example-6 of JP2011-063584 A, is used for the electron transport layer 6. An organic electroluminescent device was produced 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 electroluminescence device, and the light 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 current efficiency (cd / A) when a current density of 10 mA / cm ² was passed were measured, and the device lifetime 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 the value was expressed as a relative value when the time required for luminance (cd / m ² ) to be reduced by 25% in element reference example-1 was taken as 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 can be used as an electron transport layer of an organic electroluminescent device to enable low voltage driving, high efficiency, and long life of the device, An organic electroluminescent device provided with voltage is provided.

Claims (8)

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

(In the general formula (1), Ar ¹ represents the same group, and 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 represents a polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms (this group is substituted with 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, and X ¹ , X ^2, and X ³ each independently represent a nitrogen atom or C -H is represented, and any one of X ¹ , X ² and X ³ represents a nitrogen atom, and the remaining two represent C—H. The triazine compound according to claim 1, wherein Ar ¹ represents the same group and is an unsubstituted phenyl group, an unsubstituted naphthyl group, or an unsubstituted biphenyl group. The triazine compound according to claim 1 or 2, wherein Ar ¹ represents the same group and is a phenyl group. The triazine compound according to any one of claims 1 to 3, wherein Ar ² is an unsubstituted polycyclic aromatic hydrocarbon group having 10 to 18 carbon atoms. Ar ² is 1-naphthyl group, 2-naphthyl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl 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-fluoranthenyl group, 3-fluoranthenyl group, The triazine compound according to any one of claims 1 to 4, which is a 7-fluoranthenyl group or an 8-fluoranthenyl group.   The triazine compound according to any one of claims 1 to 5, wherein R is a methyl group.   An organic electroluminescent element material comprising the triazine compound according to claim 1.   An electron transport material for an organic electroluminescent device comprising the triazine compound according to claim 1.

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