JP2019116428A - Triazine compound and organic electroluminescent element based on the same - Google Patents

Abstract

（Ａｒ^１、Ａｒ^２及びＡｒ^３は、各々独立に、フェニル基又はビフェニリル基）
【効果】顕著に長寿命な、信頼性の高い有機電界発光素子を提供できる。
【選択図】なしPROBLEM TO BE SOLVED: To provide a hole blocking material for realizing a long life.
A triazine compound represented by the general formula (1).

(Ar ¹ , Ar ² and Ar ³ are each independently a phenyl group or a biphenylyl group)
[Effect] It is possible to provide a highly reliable organic electroluminescent device having a remarkably long life.
【Selection chart】 None

Description

  The present invention relates to a triazine compound that improves the life characteristics of the organic electroluminescent device by using the hole blocking layer of the organic electroluminescent device, and an organic electroluminescent device using the same.

  In an organic electroluminescent device, a light emitting layer containing an organic or organic metal compound emitting fluorescence, phosphorescence, etc. is sandwiched by a layer made of a charge transport material, and an anode and a cathode are attached to the outer side thereof. The light emitting element utilizes emission of light from excitons generated upon recombination thereof. In recent years, organic electroluminescent devices obtained by depositing the light emitting layer and the charge transport layer by a vapor deposition method are used in mobile phones, smartphones, thin televisions, etc. and are put to practical use. 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 blocking layer, and the electron transport layer is divided into an electron transport layer and an electron injection layer. It may be configured. In particular, the hole blocking layer reduces the leakage of electron holes from the light emitting layer to the electron transporting layer, thereby preventing the deterioration of the electron transporting layer, and the lifetime characteristics of the organic electroluminescent device Have the effect of improving.

  In recent years, an example using a triazine derivative (see, for example, Patent Document 1) as an electron transporting layer of an organic electroluminescent device has been reported. The triazine derivative disclosed in Patent Document 1 is similar to the triazine compound described in the present application, but all substituents on the triazine ring are aromatic hydrocarbons, and the substituent at the 2-position of the triazine ring is 4-biphenylyl. The triazine compound described in the present application, which is a group, wherein the substituent at the 4-position is a 3,5-disubstituted phenyl group is excellent in preventing the leakage of excitons and holes in an organic electroluminescent device Found that it had an effect. In addition, Patent Document 1 does not have any example in which the triazine derivative is used as a hole blocking layer of an organic electroluminescent device.

JP 2008-280330 A

  An object of the present invention is to provide a hole blocking material which achieves long life that is difficult to predict from conventionally known materials in an organic electroluminescent device.

  The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, when the triazine compound described in the present invention represented by the following general formula (1) is used as a hole blocking layer in an organic electroluminescent device, the device It has been found that the life characteristics of the above can be remarkably improved, and the present invention has been completed.

That is, one aspect of the present invention is
[1]
General formula (1)

(Wherein, Ar ¹ , Ar ² and Ar ³ each independently represent a phenyl group or a biphenylyl group)
A triazine compound represented by
[2]
The triazine compound according to [1], wherein Ar ¹ , Ar ² and Ar ³ are each independently a phenyl group, 2-biphenylyl group or 4-biphenylyl group;
[3]
The triazine compound according to the above [1], wherein at least one of Ar ¹ , Ar ² and Ar ³ is a biphenylyl group;
[4]
Any of the following formulas

A triazine compound according to any one of the above [1] to [3],
Or
[5]
An organic electroluminescent device comprising the triazine compound according to any one of the above [1] to [4] in a hole blocking layer and / or an electron transport layer;
It is about

  According to one aspect of the present invention, it is possible to provide an organic electroluminescent device having a remarkably long life and high reliability, thus contributing to the improvement of the life and reliability of the electronic information terminal. Play an effect.

  The triazine compound according to one aspect of the present invention is described in detail below.

The definitions of Ar ¹ , Ar ² and Ar ³ in the triazine compound (1) of the present invention will be described.

Examples of the biphenylyl group represented by Ar ¹ , Ar ² and Ar ³ include 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, and 4-biphenylyl group in terms of good performance as an organic EL material. Is preferred.

Ar ¹ , Ar ² and Ar ³ are preferably each independently a phenyl group, a 2-biphenylyl group, or a 4-biphenylyl group in terms of extending the life of the organic EL element.

Also, the ^Ar 1, Ar ² and Ar ^3, from the viewpoint of excellent lifetime of the organic EL ^element, among Ar 1, Ar ² and Ar ^3, at least one biphenylyl group (2-biphenylyl group, 3-biphenylyl It is preferable that it is group, or 4-biphenylyl group, It is more preferable that at least 1 is 2-biphenylyl group or 4-biphenylyl group, It is more preferable that at least 1 is 4-biphenylyl group.

  As a triazine compound (1) of this invention, although the thing of the structure specifically shown to the following 1-1 to 1-40 can be illustrated, this invention is not limited to these.

  Among the compounds represented by 1-1 to 1-40, the triazine compound (1) of the present invention is 1-1 to 1-3, 1-7, or 1 to 3 because it is excellent in extending the life of the organic EL device. The compound shown by 1-13 is preferable.

  Next, the method for producing the triazine compound (1) of the present invention will be described.

  The triazine compound (1) of the present invention can be produced according to the following step 1. That is, the compound represented by the following general formula (2) (hereinafter, also referred to as a compound (2)) and the boron compound represented by the following general formula (3) (hereinafter, also referred to as a boron compound (3)) are reacted The triazine compound (1) can be produced by

(Wherein, Ar ¹ , Ar ² and Ar ³ represent the same meaning as described above. X ¹ represents a halogen atom. R ¹ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, B Two R ^{1 s} of (OR ¹ ) ₂ may be the same or different, and two R ^{1 s} may together form an oxygen atom and a boron atom to form a ring.)
As a halogen atom represented by X ¹ , a fluorine atom, a chlorine atom, a bromine atom or an iodine atom can be exemplified, and a chlorine atom or a bromine is preferable because the yield of the triazine compound (1) of the present invention is good. Atoms are preferred.

As Ar ³ -B B in ^(OR ₁₎ a boron compound represented by the _{^{2 (3) (OR 1)}} 2 is not particularly limited, for _{example, B (OH) 2, B} (OMe) 2, _{^{B (O i Pr) 2,}} B (OBu) can be exemplified _2, B _(OPh) 2 or the like. Me is methyl, ⁱ Pr is isopropyl, Bu is butyl, and Ph is phenyl. Also, examples of B (OR ¹ ) ₂ when two R ¹ together form an oxygen atom and a boron atom to form a ring are not particularly limited, but from the following (I) The group represented by (VI) can be exemplified, and the group represented by (II) is preferable in terms of a good yield.

  Step 1 is a step of reacting a boron compound (3) with a compound (2) in the presence of a palladium catalyst and a base to produce the triazine compound (1) of the present invention, and a general Suzuki-Miyaura reaction By applying the conditions, the triazine compound (1) of the present invention can be obtained in high yield.

  The compound (2) used for the process 1 can be manufactured, for example according to the method currently disclosed by Unexamined-Japanese-Patent No. 2016-121120 grade | etc.,.

  The boron compound (3) used in Step 1 can be produced by a general method well known to those skilled in the art, or a commercially available product may be used. Although there is no restriction | limiting in particular in the molar equivalent of boron compound (3) to be used, It is preferable to use 0.5-3.0 molar equivalent with respect to a compound (2) from the point with a favorable reaction yield.

  The palladium catalyst used in step 1 is not particularly limited, and specific examples thereof include palladium salts such as palladium chloride, palladium acetate, palladium trifluoroacetate and palladium nitrate. Furthermore, complex compounds such as π-allylpalladium chloride dimer, palladium acetylacetonato, tris (dibenzylideneacetone) dipalladium, bis (dibenzylideneacetone) palladium, dichlorobis (acetonitrile) palladium, dichlorobis (benzonitrile) palladium, etc. Dichlorobis (triphenylphosphine) palladium, tetrakis (triphenylphosphine) palladium, dichloro (1,1′-bis (diphenylphosphino) ferrocene) palladium, bis (tri-tert-butylphosphine) palladium, bis (tricyclohexylphosphine) Examples thereof include palladium complexes having a tertiary phosphine such as palladium and dichlorobis (tricyclohexylphosphine) palladium as a ligand. Luo added tertiary phosphine to a palladium salt or complex compound may be prepared in the reaction system. Examples of tertiary phosphines which can be used in this case include triphenylphosphine, trimethylphosphine, tributylphosphine, tri (tert-butyl) phosphine, tricyclohexylphosphine, tert-butyldiphenylphosphine, 9,9-dimethyl-4, 5-bis (diphenylphosphino) xanthene, 2- (diphenylphosphino) -2 '-(N, N-dimethylamino) biphenyl, 2- (di-tert-butylphosphino) biphenyl, 2- (dicyclohexylphosphino) ) Biphenyl, bis (diphenylphosphino) methane, 1,2-bis (diphenylphosphino) ethane, 1,3-bis (diphenylphosphino) propane, 1,4-bis (diphenylphosphino) butane, 1,1 '-Bis (diphenyl phosphino) Ferrocene, tri (2-furyl) phosphine, tri (o-tolyl) phosphine, tri (2,5-xylyl) phosphine, 2,2'-bis (diphenylphosphino) -1,1'-binaphthyl, 2-dicyclo Hexyl phosphino-2 ', 4', 6'- triisopropyl biphenyl etc. can be illustrated.

  Among them, a palladium complex having a tertiary phosphine as a ligand is preferable in terms of a good yield, and a palladium complex having 2-dicyclohexylphosphino-2 ', 4', 6'-triisopropylbiphenyl as a ligand is preferable. More preferable. The molar ratio of tertiary phosphine to palladium salt or complex compound is preferably in the range of 1:10 to 10: 1, and further preferably in the range of 1: 2 to 3: 1 in terms of a good yield. preferable. The amount of palladium catalyst used in step 1 is not limited, but the molar equivalent of palladium catalyst is preferably in the range of 0.005 to 0.5 molar equivalent with respect to compound (2) in terms of good yield. .

  The base used in step 1 is not particularly limited, and examples thereof include metal hydroxide salts such as sodium hydroxide, potassium hydroxide and calcium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate and cesium carbonate Metal carbonates, metal acetates such as potassium acetate and sodium acetate, metal phosphates such as potassium phosphate and sodium phosphate, metal fluorides such as sodium fluoride, potassium fluoride and cesium fluoride, sodium methoxide And metal alkoxides such as potassium methoxide, sodium ethoxide, potassium isopropyl oxide, potassium tert-butoxide and the like. Among them, metal carbonates and metal phosphates are preferred, and potassium carbonate is more preferred, from the viewpoint of good reaction yield. Although the amount of the base used is not particularly limited, the molar ratio of the base to the boron compound (3) is preferably in the range of 1: 2 to 10: 1, in terms of a good reaction yield, 1: 1 More preferably, it is in the range of -4: 1.

  Step 1 can be carried out in a solvent. Examples of the solvent that can be used in step 1 include water, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether (CPME), tetrahydrofuran (THF), ethers such as 2-methyltetrahydrofuran, 1,4-dioxane, dimethoxyethane, benzene, Aromatic hydrocarbons such as toluene, xylene, mesitylene and tetralin, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl carbonate, 4-fluoroethylene carbonate, etc., ethyl acetate, butyl acetate, methyl propionate, Ethyl propionate, methyl butyrate, esters such as γ-lactone, N, N-dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl pyro Amide such as N-don (NMP), urea such as N, N, N ', N'-tetramethylurea (TMU), N, N'-dimethylpropyleneurea (DMPU) or dimethyl sulfoxide (DMSO), methanol, ethanol, Examples thereof include alcohols such as isopropyl alcohol, butanol, octanol, benzyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 2,2,2-trifluoroethanol and the like, and these are mixed in an arbitrary ratio. You may use it. There is no particular limitation on the amount of solvent used. Among these, water, ether, amide, alcohol, and a mixed solvent thereof are preferable in that the reaction yield is good, and THF, 1,4-dioxane and a mixed solvent of these with water are more preferable.

  Step 1 can be carried out at a temperature appropriately selected from 0 ° C. to 200 ° C., and is preferably carried out at a temperature appropriately selected from 100 ° C. to 160 ° C. in terms of a good reaction yield.

  The triazine compound (1) of the present invention can be obtained by ordinary treatment after completion of step 1. If necessary, purification may be carried out by recrystallization, column chromatography, sublimation, preparative HPLC or the like.

  The triazine compound (1) of the present invention is not particularly limited, but can be used as a material for an organic electroluminescent device, and as a material for an electron transport layer of an organic electroluminescent device or a material for a hole blocking layer Can be used preferably.

  The triazine compound (1) of the present invention can be preferably used as a hole blocking material (electron transport material, electron injection material, etc.) of an organic electroluminescent device. At this time, commonly known anodes, hole injection layers, hole transport layers, electron blocking layers, light emitting layers, light emitting layer dopants, light emitting layer hosts, electron transport layers, electron injection layers, cathodes, etc. used in combination Materials can be used at the discretion of the person skilled in the art.

  The configuration of the organic electroluminescent device may be any conventionally known one, and is not particularly limited.

Although there is no limitation in particular in the manufacturing method of the thin film for organic electroluminescent elements which contains the triazine compound (1) of this invention, The film-forming by a vacuum evaporation method can be mentioned as a preferable example. The film formation by the vacuum evaporation method can be performed by using a general-purpose vacuum evaporation apparatus. The degree of vacuum of the vacuum chamber at the time of forming a film by a vacuum evaporation method is a diffusion pump, a turbo molecular pump, a cryo which is generally used in that the manufacturing tact time for manufacturing an organic electroluminescent device is short and the manufacturing cost is superior. It is preferably about 1 × 10 ⁻² to 1 × 10 ⁻⁶ Pa which can be reached by a pump or the like, and the deposition rate is preferably 0.005 to 10 nm / second, depending on the thickness of the film to be formed. Moreover, the thin film for organic electroluminescent elements which consists of a triazine compound (1) of this invention can be manufactured also by the solution apply | coating method. For example, the triazine compound (1) of the present invention is dissolved in an organic solvent such as chloroform, dichloromethane, 1,2-dichloroethane, chlorobenzene, toluene, ethyl acetate or tetrahydrofuran, and a spin coating method using a general-purpose device, an inkjet method Film formation by a cast method or a dip method is also possible.

  The triazine compound (1) of the present invention has high solubility in chloroform, dichloromethane, 1,2-dichloroethane, chlorobenzene, toluene, ethyl acetate, tetrahydrofuran and the like, so spin coating method, ink jet method using a general-purpose device, Film formation by a cast method, dip method or the like is also possible.

  Typical structures of the organic electroluminescent device of the present invention include a substrate, an anode, a hole injection layer, a light emitting layer of a hole transport layer, an electron transport layer, and a cathode.

  The anode and the cathode of the organic electroluminescent element are connected to a power source via an electrical conductor. The organic electroluminescent device operates by applying a potential between the anode and the cathode. Holes are injected from the anode into the organic electroluminescent device, and electrons are injected into the organic electroluminescent device at the cathode.

  The organic electroluminescent device is typically placed on a substrate, and the anode or the cathode can be in contact with the substrate. The electrode in contact with the substrate is conveniently referred to as the lower electrode. In general, the lower electrode is an anode, but the organic electroluminescent device of the present invention is not limited to such a form.

  The substrate may be light transmissive or opaque depending on the intended light emission direction. The light transmission properties can be confirmed by electroluminescence through the substrate. In general, transparent glass or plastic is employed as the substrate. The substrate may be a composite structure comprising multiple material layers.

  If the electroluminescent emission is confirmed through the anode, the anode is formed to either pass or substantially transmit the emission.

  Common transparent anode (anode) materials used in the present invention include indium-tin oxide (ITO), indium-zinc oxide (IZO), or tin oxide. Furthermore, other metal oxides such as aluminum or indium-doped tin oxide, magnesium-indium oxide, or nickel-tungsten oxide are also preferably used. In addition to these oxides, metal nitrides, such as gallium nitride, metal selenides, such as zinc selenide, or metal sulfides, such as zinc sulfide, can be used as the anode. The anode can be modified with plasma deposited fluorocarbons.

  If the electroluminescent emission is confirmed only through the cathode, the transmission properties of the anode are not important and any conductive material transparent, opaque or reflective can be used. Examples of conductors for this application include gold, iridium, molybdenum, palladium, platinum and the like.

  The hole injection layer can be provided between the anode and the hole transport layer. The material of the hole injection layer improves the film forming properties of the organic material layer, such as the hole transport layer and the hole injection layer, and serves to facilitate the injection of holes into the hole transport layer. Examples of materials suitable for use in the hole injection layer include porphyrin compounds, plasma deposited fluorocarbon polymers, and amines having an aromatic ring such as biphenyl or carbazole, such as m-MTDATA (4,4 ') , 4 ''-tris [(3-methylphenyl) phenylamino] triphenylamine), 2T-NATA (4,4 ', 4' '-tris [(N-naphthalen-2-yl) -N-phenylamino] Triphenylamine), triphenylamine, tolylamine, tolyldiphenylamine, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N, N'N'-tetrakis (4-methylphenyl) -1,1'-biphenyl-4,4'-diamine, MeO-TPD N, N, N'N'-tetrakis (4-methoxyphenyl) -1,1'-biphenyl-4,4'-diamine), N, N'-diphenyl-N, N'-dinaphthyl-1,1 ' -Biphenyl-4,4'-diamine, N, N'-bis (methylphenyl) -N, N'-bis (4-normalbutylphenyl) phenanthrene-9,10-diamine, N, N'-diphenyl-N , N′-bis (9-phenylcarbazol-3-yl) -1,1′-biphenyl-4,4′-diamine and the like.

  The hole transport layer of the organic electroluminescent device preferably contains one or more hole transport compounds (hole transport materials), for example, an aromatic tertiary amine. An aromatic tertiary amine is a compound containing one or more trivalent nitrogen atoms, and the trivalent nitrogen atoms are bonded only to carbon atoms, and one or more of these carbon atoms are aromatic rings. Form. The aromatic tertiary amine may be an arylamine such as a monoarylamine, a diarylamine, a triarylamine or a polymeric arylamine.

  As the hole transport material, aromatic tertiary amines having one or more amino groups can be used. In addition, polymeric hole transport materials can be used. For example, poly (N-vinylcarbazole) (PVK), polythiophene, polypyrrole, polyaniline and the like can be used.

  Specifically, NPD (N, N'-bis (naphthalen-1-yl) -N, N'-diphenyl-1,1'-biphenyl-4,4'-diamine), α-NPD (N, N) '-Di (1-naphthyl) -N, N'-diphenyl-1,1'-biphenyl-4,4'-diamine), TPBi (1,3,5-tris (1-phenyl-1H-benzimidazole) 2-yl) benzene), TPD (N, N'-bis (3-methylphenyl) -N, N'-diphenyl-1,1'-biphenyl-4,4'-diamine) and the like.

  Dipyrazino [2,3-f: 2 ', 3'-h] quinoxaline-2,3,6,7,10,11-hexacarbonitrile as charge generation layer between hole injection layer and hole transport layer (HAT-CN), 7,7 ', 8,8'-tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrafluoro-7,7', 8,8'-tetracyanoquinodi A layer containing methane (F 4 -TCNQ) or the like may be provided, and the hole transport layer may be doped with these compounds.

  The light emitting layer of the organic electroluminescent device contains a phosphorescent material or a fluorescent material, and in this case, light emission occurs as a result of recombination of electron-hole pairs in this region. The light emitting layer may be formed of a single material containing both a small molecule and a polymer, but more generally is formed of a host material doped with a guest compound, and the emission mainly originates from the dopant, It can emit any color.

  Examples of host materials for the light emitting layer include compounds having a biphenyl group, a fluorenyl group, a triphenylsilyl group, a carbazole group, a pyrenyl group, or an anthranyl group, and these materials can be used alone or in combination. It can also be used as a mixture with the triazine compound (1) of the invention, and specifically, DPVBi (4,4'-bis (2,2-diphenylvinyl) -1,1'-biphenyl), TBADN (2- Tert-butyl-9,10-di (2-naphthyl) anthracene), ADN (9,10-di (2-naphthyl) anthracene), CBP (4,4'-bis (carbazol-9-yl) biphenyl), CDBP (4,4'-bis (carbazol-9-yl) -2,2'-dimethylbiphenyl), 9,10-bis (biphenyl) anthrase Etc. The.

  The host material in the light emitting layer may be an electron transporting material as defined below, a hole transporting material as defined above, another material supporting hole-electron recombination, or a combination of these materials.

  Examples of fluorescent dopants include pyrene, anthracene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine and quinacridone, dicyanomethylene pyran compound, thiopyran compound, polymethine compound, pyrilium or thiapyrilium compound, fluorene derivative, periflanthene derivative, indeno Perylene derivatives, bis (azinyl) amine boron compounds, bis (azinyl) methane compounds, carbostyryl compounds, or 4Cz-IPN (2,4,5,6-tetra (9-carbazolyl) isophthalonitrile), 2Cz-PN ( The compound etc. which express thermal activation delayed fluorescence (TADF), such as 4, 5- di (9-carbazolyl) phthalonitrile, etc. are mentioned.

  Examples of useful phosphorescent dopants include organometallic complexes of transition metals such as iridium, platinum, palladium, osmium and the like.

Examples of dopants include Alq ₃ (tris (8-hydroxyquinoline) aluminum), DPAVBi (4,4′-bis [4- (di-p-tolylamino) styryl] biphenyl), perylene, Ir (PPy) ₃ ( Examples include tris (2-phenylpyridine) iridium (III), FlrPic (bis (3,5-difluoro-2- (2-pyridyl) phenyl- (2-carboxypyridyl) iridium) and the like.

  The triazine compound (1) of the present invention can be used as a thin film-forming material used to form the hole blocking layer or the electron transport layer of the organic electroluminescent device of the present invention. The hole blocking layer or the electron transport layer may contain other electron transporting materials. Other electron transporting materials include alkali metal complexes, alkaline earth metal complexes, typical element compounds, rare earth metal complexes and the like, for example, lithium 8-hydroxyquinolinate (Liq), bis (8-hydroxyquinolito Inerts) zinc, bis (8-hydroxyquinolinate) copper, bis (8-hydroxyquinolinate) manganese, tris (8-hydroxyquinolinate) aluminum, tris (2-methyl-8-hydroxyquinolinate) Aluminum, tris (8-hydroxyquinolinate) gallium, bis (10-hydroxybenzo [h] quinolinate) beryllium, bis (10-hydroxybenzo [h] quinolinate) zinc, bis (2-methyl-8-quinolinate) chloro Gallium, bis (2-methyl-8-quinolinate) (o-cresolate) Gallium, bis (2-methyl-8-quinolinato) -1-naphthoquinone Trad aluminum, bis (2-methyl-8-quinolinato) -2-naphthoquinone Trad gallium, and the like.

  In the organic electroluminescent device of the present invention, an electron injection layer may be provided for the purpose of improving the electron injection property and improving the device characteristics (for example, light emission efficiency, low voltage drive, or high durability).

As compounds which can be used as the electron injection layer, there are fluorenone, anthraquinodimethane, diphenoquinone, thiopyrandioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane Or antron. Further, metal complexes, alkali metal oxides, alkaline earth oxides, rare earth oxides, alkali metal halides, alkaline earth halides, rare earth halides, SiO _x , AlO _x , SiN exemplified as the above-mentioned electron transporting materials _{X, SiON, AlON, GeO X} , LiO X, LiON, TiO X, TiON, TaO X, TaON, TaN X, various oxides such as C, nitrides, and inorganic compounds such as oxynitride can be used. When light emission is seen only through the anode, the cathode used in the organic electroluminescent device of the present invention can be formed from almost any conductive material. Preferred cathode 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 ) mixture, indium , Lithium / aluminum mixtures, rare earth metals and the like.

It is a cross-sectional schematic diagram of the organic electroluminescent element produced by evaluation example -1.

11. Glass substrate with ITO transparent electrode 12. Hole injection layer 13. First hole transport layer 14. Second hole transport layer 15. Electron blocking layer 16. Light emitting layer 17. First electron transport layer 18. Second electron transport layer 19. Cathode layer

  EXAMPLES The present invention will be described in more detail by the following Examples and Comparative Examples, but the present invention is not construed as being limited thereto.

The following analysis methods were used to identify the triazine compound (1) of the present invention. For the measurement of ¹ H-NMR, using a ^{Bruker ASCEND TM AVANCE III HD (400MHz} ). ¹ H-NMR was measured using heavy chloroform (CDCl ₃ ) as a measurement solvent and using tetramethylsilane (TMS) as an internal standard substance. Moreover, the reagents used the commercial item.

  Reference Example 1

  3-bromo-5-chlorobenzoic acid (5.9 g) and DMF (25 μL) were suspended in toluene (22.5 mL). Thionyl chloride (3.6 g) was added to this suspension and heated to reflux for 5 hours. After allowing to cool, the solvent was distilled off under reduced pressure to obtain 3-bromo-5-chlorobenzoic acid chloride. This was used for the next reaction without purification.

  Under an argon atmosphere, 4-cyanobiphenyl (9.4 g) was added to the obtained 3-bromo-5-chlorobenzoic acid chloride, and suspended in chloroform (50 mL). The suspension was cooled in an ice bath, then antimony chloride (7.5 g) was added and heated to reflux for 2 hours. Then, it cooled to room temperature and the obtained reaction mixture was dripped in 30% aqueous ammonia. The resulting solid was collected by filtration, washed with water and then with methanol. The filtered product was suspended in toluene, and heated and stirred for 30 minutes. The heated suspension was filtered and the filtrate was evaporated under reduced pressure. The resulting solid is washed with toluene and then methanol to give the desired 4,6-bis (4-biphenylyl) -2- (3-bromo-5-chlorophenyl) -1,3,5-triazine (compound A). -1, to give a white solid (yield 5.9 g, 41%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 8.84 (d, J = 8.6 Hz, 4 H), 8.81 (dd, J = 1.6, 1.4 Hz, 1 H), 8.71 (Dd, J = 1.9, 1.4 Hz, 1 H), 7.83 (d, J = 8.6 Hz, 4 H) 7.76 (t, J = 1.9 Hz, 1 H), 7.73 (dt , J = 7.3, 1.2 Hz, 4 H), 7.52 (d, J = 7.3 Hz, 4 H), 7.44 (dt, J = 7.3, 1.2 Hz, 2 H).

  Reference Example 2

  Under an argon atmosphere, 2- (4-biphenylyl) -4- (3-bromo-5-chlorophenyl) -6-phenyl-1,3,5-triazine (8.3 g), phenylboronic acid (2.2 g) and Tetrakis (triphenylphosphine) palladium (575 mg) was suspended in THF (81 mL). To this suspension was added 5.0 M aqueous sodium hydroxide solution (9.9 mL), and the mixture was stirred at reflux for 21 hours. After allowing to cool, methanol was added to the reaction mixture, and the precipitated solid was collected by filtration, washed with methanol and then with water. The resulting solid is purified by silica gel column chromatography (chloroform) and then recrystallized (toluene) to give 2- (5-chlorobiphenyl-3-yl) -4- (4-biphenylyl) -6-phenyl-1 White solid of 3,5-triazine (referred to as compound C-1) was obtained (yield 6.5 g, 79%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 8.89 (dd, J = 1.4 Hz, 1.4 Hz, 1 H), 8.85 (d, J = 8.4 Hz, 2 H), δ 8.80 (D, J = 6.6 Hz, 2 H), 8.73 (dd, J = 1.7, 1.5 Hz, 1 H), 7.84-7.82 (m, 3 H), 7.74-7. 71 (m, 4 H), 7.67-7.58 (m, 3 H), 7.56-7.49 (m, 4 H), 7.48-7.41 (m, 2 H).

  Example 1

  Under argon atmosphere, 4,6-bis (4-biphenylyl) -2- (3-bromo-5-chlorophenyl) -1,3,5-triazine (2.9 g), phenylboronic acid (1.5 g), acetic acid Palladium (22 mg) and 2-dicyclohexylphosphino-2 ′, 4 ′, 6′-triisopropylbiphenyl (143 mg) were suspended in THF (100 mL). To this suspension was added 3.0 M aqueous potassium carbonate solution (8.0 mL), and the mixture was heated to reflux for 24 hours. After cooling, water and methanol were added. The resulting solid is collected by filtration, washed with water and then with methanol, and the desired 4,6-bis (4-biphenylyl) -2- (1,1 ′: 3 ′, 1 ′ ′-terphenyl-5′- A gray solid of (yl) -1,3,5-triazine (referred to as Compound B-1) was obtained (yield 3.0 g, 99%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 9.02 (d, J = 1.8 Hz, 2 H), 8. 90 (d, J = 8.6 Hz, 4 H), 8.07 (t, J = 1.8 Hz, 1 H), 7.85 (d, J = 8.6 Hz, 4 H), 7.82-7.85 (m, 4 H), 7.72-7.75 (m, 4 H), 7 .58 (tt, J = 7.4, 1.2 Hz, 4 H), 7.53 (tt, J = 7.3, 1.2 Hz, 4 H), 7.47 (tt, J = 7.4, 1 .2 Hz, 2 H), 7.44 (tt, J = 7.3, 1.2 Hz, 2 H).

  Example 2

  Under an argon atmosphere, 2- (4-biphenylyl) -4- (5-chlorobiphenyl-3-yl) -6-phenyl-1,3,5-triazine (2.5 g) and 4-biphenylboronic acid (3. 4). 0 g) was suspended in 1,4-dioxane (80 mL). In this suspension, a solution of palladium acetate (112 mg) and 2-dicyclohexylphosphino-2 ', 4', 6'-triisopropylbiphenyl (425 mg) in 1,4-dioxane (10 mL), and 2.0 M potassium carbonate The aqueous solution (10 mL) was added and stirred at 100 ° C. for 24 hours. After cooling to room temperature, the solvent was evaporated, methanol was added to the residue, the solid was collected by filtration, and washed successively with methanol, water and hexane. The resulting solid is purified by column chromatography (chloroform) and then recrystallization (toluene) to give the desired 2- (4-biphenylyl) -4-phenyl-6- (1,1 ': 3', 1 ' ': 4' ', 1' ''-quaterphenyl-5'-yl) -1,3,5-triazine (referred to as Compound B-2) was obtained as a white solid (Yield 2.3 g, Yield 76%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 9.05 (dd, J = 1.7, 1.6 Hz, 1 H), 9.01 (dd, J = 1.7, 1.6 Hz, 1 H) , 8.89 (d, J = 8.5 Hz, 2 H), 8.83 (dd, J = 7.6, 1.4 Hz, 2 H), 8. 10 (dd, J = 1.7, 1.7 Hz) , 1 H), 7.91 (d, J = 8.3 Hz, 2 H), 7. 84 (d, J = 8.5 Hz, 4 H), 7. 80 (d, J = 8.3 Hz, 2 H), 7 70-70.74 (m, 4H), 7.38-7.65 (m, 12H).

  Example 3

  Under an argon atmosphere, 2- (4-biphenylyl) -4- (3-bromo-5-chlorophenyl) -6-phenyl-1,3,5-triazine (3.49 g) and 4-biphenylboronic acid (5.54 g) ) Was suspended in 1,4-dioxane (90 mL). In this suspension, a solution of palladium acetate (157 mg) and 2-dicyclohexylphosphino-2 ', 4', 6'-triisopropylbiphenyl (594 mg) in 1,4-dioxane (50 mL), and 2.0 M carbonate Aqueous potassium solution (18 mL) was added and stirred for 30 hours under reflux. After cooling to room temperature, water was added to the reaction mixture, the solid was collected by filtration, and washed successively with methanol, water and hexane. Alumina is added to the obtained solid, subjected to Soxhlet extraction (chloroform), and then purified by recrystallization (toluene) to obtain 4- (4-biphenylyl) -6- (1,1 ': 4', 1 ''. : 3 ′ ′, 1 ′ ′ ′: 4 ′ ′ ′, 1 ′ ′ ′ ′-quincphenyl-5 ′ ′-yl) -2-phenyl-1,3,5-triazine (compound B-3) ) Was obtained (yield 3.2 g, yield 67%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 9.06 (d, J = 1.6 Hz, 2 H), 8.89 (d, J = 8.4 Hz, 2 H), 8.84 (d, J = 6.2 Hz, 2 H), 8. 15 (s, 1 H), 7. 92 (d, J = 8.2 Hz, 4 H), 7. 84 (d, J = 8.4 Hz, 2 H), 7. 80 (D, J = 8.2 Hz, 4 H), 7.74-7. 70 (m, 6 H), 7.65-7. 60 (m, 3 H), 7.53-7. 49 (m, 6 H) , 7.44-7.38 (m, 3H).

  Example 4

  Under an argon atmosphere, 4,6-bis (4-biphenylyl) -2- (3-bromo-5-chlorophenyl) -1,3,5-triazine (5.8 g), 2-biphenylyl boronic acid (4.8 g) 2.) Palladium acetate (22 mg) and 2-dicyclohexylphosphino-2 ', 4', 6'-triisopropylbiphenyl (95.3 mg) were suspended in THF (100 mL). To this suspension was added 3.0 M aqueous potassium carbonate solution (16.0 mL), and the mixture was heated to reflux for 24 hours. After cooling, water and methanol were added. The resulting solid is collected by filtration, washed with water and then with methanol, and the desired 4,6-bis (4-biphenylyl) -2- (1,1 ': 2', 1 '': 3 '', 1 '. A gray solid was obtained (Yield 7) of “2 ′ ′, 1 ′ ′ ′ ′-quincphenyl-5 ′ ′-yl) -1,3,5-triazine (referred to as Compound B-4). .2 g, 94% yield).

¹ H-NMR (THF-d ₈ ) δ (ppm): 8.79 (d, J = 8.6 Hz, 4 H), 8.47 (d, J = 1.7 Hz, 2 H), 7.91 (d , J = 8.6 Hz, 4 H), 7.81 (d, J = 8.3 Hz, 4 H), 7.33-7.54 (m, 19 H), 7.28 (d, J = 8.3 Hz, 4H), 7.23 (t, J = 7.3 Hz, 2H).

  Example 5

  In an argon atmosphere, 2,4-bis (4-biphenylyl) -6- [3- (2-biphenylyl) -5-chloro] phenyl-1,3,5-triazine (6.00 g), 4-biphenylboronic acid (2.50 g), palladium acetate (25.7 mg), and 2-dicyclohexylphosphino-2 ', 4', 6'-triisopropylbiphenyl (107 mg) were dissolved in tetrahydrofuran (200 mL). To this solution was added 2.0 M aqueous potassium carbonate solution (14 mL), and the mixture was stirred under reflux for 74 hours. After cooling to room temperature, the reaction solution was concentrated under reduced pressure. To the concentrate was added water, methanol and hexane, and the solid was collected by filtration and washed successively with methanol, water and hexane. The solid was dissolved in toluene (200 mL), silica gel was added, and the mixture was filtered through celite, and the filtrate was concentrated under reduced pressure. The solid obtained by drying this concentrated solution is purified by recrystallization (toluene) to obtain 2,4-bis (4-biphenylyl) -6- (1,1 ′: 2 ′, 1 ′ ′: 3). A white solid of '', 1 '' ': 4' '', 1 '' ''-quincphenyl-5 ''-yl) -1,3,5-triazine (referred to as Compound B-5). Obtained (yield 5.76 g, yield 81%).

¹ H-NMR (THF-d8) δ (ppm): 8.97 (t, J = 1.6 Hz, 1 H), 8.88 (d, J = 8.6 Hz, 4 H), 8.74 (t, J = 1.6 Hz, 1 H), 7.90 (d, J = 8.7 Hz, 4 H), 7.78 (d, J = 7.5 Hz, 4 H), 7.68-7.74 (m, 6 H) ), 7.61 (d, J = 8.5 Hz, 2 H), 7.30-7.56 (m, 16 H), 7.19-7.24 (m, 1 H).

  Structural formula of the compound used for preparation of the organic electroluminescent element which has triazine compound (1) of this invention as a structural component and performance evaluation, and its abbreviation are shown below.

Evaluation Example 1
As a substrate, a glass substrate with an ITO transparent electrode in which an indium tin oxide (ITO) film having a width of 2 mm was patterned in a stripe shape was used. The substrate was washed with isopropyl alcohol and then surface-treated by oxygen plasma washing. Each layer was vacuum deposited on the cleaned substrate by a vacuum deposition method, and an organic electroluminescent device having a light emitting area of 4 mm ² as shown in FIG. 1 was prepared.

First, the glass substrate was introduced into a vacuum deposition tank, and the pressure was reduced to 1.0 × 10 ⁻⁴ Pa.
Thereafter, a hole injection layer 12, a first hole transport layer 13, a second hole transport layer 14, an electron blocking layer 15, and a light emitting layer as an organic compound layer on a glass substrate with an ITO transparent electrode shown by 11 in FIG. 16, the first electron transport layer 17 and the second electron transport layer 18 were sequentially formed, and then the cathode layer 19 was formed.

  The materials forming each layer of the organic electroluminescent device were vacuum deposited by resistance heating.

  As the hole injection layer 12, HIL-1 was vacuum deposited at a deposition rate of 0.15 nm / sec to a thickness of 55 nm.

  As the first hole transport layer 13, HAT-CN was vacuum deposited at a deposition rate of 0.025 nm / sec to a thickness of 5 nm.

  As the second hole transport layer 14, HTL-2 was vacuum deposited at a deposition rate of 0.15 nm / sec to a thickness of 10 nm.

  As the electron blocking layer 15, EBL-1 was vacuum deposited at a deposition rate of 0.15 nm / sec to a thickness of 10 nm.

  As the light emitting layer 16, a combination of BH-1 and BD-1 at a film forming speed of 0.18 nm / sec and a film thickness of 25 nm (BH-1 / BD-1 = 95.0 / 5.0 (weight ratio) Vacuum deposition).

  As the hole blocking layer 17, Compound B-1 synthesized in Synthesis Example 1 of the present invention was vacuum deposited at a film forming speed of 0.15 nm / sec.

  As the electron transport layer 18, ETL-1 and Liq were vacuum deposited at a film forming speed of 0.15 nm / sec to a film thickness of 25 nm (co-evaporation of ETL-1 / Liq = 50/50 (weight ratio)).

  Finally, a metal mask was disposed to be orthogonal to the ITO stripes, and a cathode layer 19 was formed. The cathode layer 19 is formed by vacuum deposition of magnesium / silver (weight ratio 80/20) and silver in this order at film thicknesses of 0.5 nm / sec and 0.2 nm / sec to thicknesses of 80 nm and 20 nm, respectively. , 2 layer structure.

  Each film thickness was measured with a stylus type film thickness measurement meter (DEKTAK, manufactured by Veeco). Furthermore, this element was sealed in a nitrogen atmosphere glove box with an oxygen and water concentration of 1 ppm or less. Sealing used the sealing cap made from glass, and the said film-forming board | substrate epoxy-type ultraviolet-ray cured resin (made by Nagase ChemteX Corp.).

Evaluation Example 2
In the hole blocking layer 17 of Evaluation Example 1, an organic electric field was obtained in the same manner as in Evaluation Example 1 except that the compound B-2 synthesized in Synthesis Example 2 was used instead of the compound B-1. A light emitting element was produced.

Comparative Example 1
An organic electroluminescent element was produced in the same manner as in Evaluation Example 1 except that HBL-1 was used in place of compound B-1 in the hole blocking layer 17 of Evaluation Example 1.

A direct current was applied to the organic electroluminescent devices produced in Evaluation Examples 1 and 2 and Comparative Example 1, and the light emission characteristics were evaluated using a luminance meter manufactured by TOPCON, LUMINANCE METER (BM-9). As the life characteristics (h), the luminance decay time during continuous lighting when a current density of 25 mA / cm ² flows is measured, and the time when the luminance (cd / m ² ) decreases by 10% is the device life (h) ). In addition, about the element life of each evaluation example, the element life (h) in comparative example 1 was set to 100, and it showed with the relative value.

  It was found that the organic electroluminescent device using the triazine compound (1) of the present invention was significantly superior in life characteristics as compared with Comparative Example-1.

  The organic electroluminescent device using the triazine compound (1) of the present invention can be driven for a long time as compared with the organic electroluminescent device using the existing material. The triazine compound (1) of the present invention is also applicable to a light emitting host layer, an electron transport layer, etc. in addition to the hole blocking layer of this example. Furthermore, application to various organic electroluminescent devices using fluorescent light emitting materials and phosphorescent light emitting materials as well as devices using TADF light emitting materials is also possible. In addition, the triazine compound (1) of the present invention has a high solubility, and it is possible not only to use a vacuum evaporation method but also to form a device using a coating method. Furthermore, it is useful not only for applications such as flat panel displays, but also for lighting applications that require low power consumption.

Claims (5)

General formula (1)

(Wherein, Ar ¹ , Ar ² and Ar ³ each independently represent a phenyl group or a biphenylyl group)
A triazine compound represented by Ar ^1, Ar ² and Ar ³ are each independently a phenyl group, a 2-biphenylyl group, or a 4-biphenylyl group, a triazine compound according to claim 1. The triazine compound according to claim 1, wherein at least one of Ar ¹ , Ar ² and Ar ³ is a biphenylyl group. Any of the following formulas

The triazine compound according to any one of claims 1 to 3 represented by   An organic electroluminescent device comprising the triazine compound according to any one of claims 1 to 4 in a hole blocking layer and / or an electron transporting layer.

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