JP7780873B2 - Triazine compounds for use in organic electroluminescent devices - Google Patents

Description

The present disclosure relates to a triazine compound, a material for an organic electroluminescent device containing the triazine compound, and an organic electroluminescent device.

Organic electroluminescent devices are beginning to be put to practical use, primarily in small mobile devices. However, further expansion of their applications requires improved performance, and materials with high luminous efficiency and long life are needed.

Patent Document 1 discloses a triazine compound that is a material for an organic electroluminescent device that is highly efficient and can reduce the driving voltage.
Patent Document 2 discloses a triazine compound that is a material for an organic electroluminescent device that is highly efficient and can reduce the driving voltage.
Patent Document 3 discloses a triazine compound that is a material for an organic electroluminescent device that has high heat resistance and can reduce the driving voltage.

JP 2017-178931 A Korean Patent Publication No. 1666751 JP 2011-63584 A

However, there is strong market demand for expanded applications and environments in which they can be used, and the triazine compounds disclosed in Patent Documents 1, 2, and 3 do not fully satisfy the two characteristics of high luminous efficiency and long life, so there is a demand for materials that achieve these two characteristics at an even higher level.

Therefore, one aspect of the present disclosure is directed to providing a triazine compound that contributes to the formation of an organic electroluminescent device that exhibits high luminous efficiency and long life characteristics at a high level.
Another aspect of the present disclosure is directed to providing a material for an organic electroluminescent device, which contains the triazine compound.
Furthermore, still another aspect of the present disclosure is directed to providing an organic electroluminescent device that exhibits high luminous efficiency and long life characteristics at a high level.

According to one aspect of the present disclosure, there is provided a triazine compound represented by formula (1):

During the ceremony,
Ar ¹ and Ar ² each independently represent a phenyl group, a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted with one or more substituents selected from the group consisting of a fluorine atom, a methyl group, and a cyano group;
^Ar3 represents a polycyclic aromatic group optionally substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group;
^Ar4 represents a phenyl group, an azaphenyl group, a diazaphenyl group, an azanaphthyl group, or a diazanaphthyl group, and these groups may be substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group;
^X1 represents a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 1,4-naphthylene group, a 1,5-naphthylene group, a 2,6-naphthylene group, or a 2,7-naphthylene group;
^X2 represents a phenylene group, a naphthylene group, an azaphenylene group, a diazaphenylene group, an azanaphthylene group, or a diazanaphthylene group;
p represents 1 or 2;
However, when p is 2, two X ^1s may be the same or different;
q represents 0, 1 or 2;
However, when q is 2, two X ^{2 s} may be the same or different.

According to another aspect of the present disclosure, there is provided a material for an organic electroluminescent device containing the above-described triazine compound.

According to yet another aspect of the present disclosure, there is provided an organic electroluminescent device containing the above-described triazine compound.

According to one aspect of the present disclosure, a triazine compound can be provided that contributes to the formation of an organic electroluminescent device that exhibits high luminous efficiency and long life characteristics at a high level. According to another aspect of the present disclosure, a material for an organic electroluminescent device that includes the triazine compound can be provided. According to yet another aspect of the present disclosure, an organic electroluminescent device that exhibits high luminous efficiency and long life characteristics at a high level can be provided.

1 is a schematic cross-sectional view showing an example of a layered structure of an organic electroluminescence element according to one embodiment of the present disclosure. FIG. 1 is a schematic cross-sectional view showing another example of a laminated structure of an organic electroluminescence element according to one embodiment of the present disclosure (structure of element example 1).

The triazine compound according to one embodiment of the present disclosure is described in detail below.

<Triazine compounds>
A triazine compound according to one embodiment of the present disclosure is a triazine compound represented by formula (1):

During the ceremony,
Ar ¹ and Ar ² each independently represent a phenyl group, a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted with one or more substituents selected from the group consisting of a fluorine atom, a methyl group, and a cyano group;
^Ar3 represents a polycyclic aromatic group optionally substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group;
^Ar4 represents a phenyl group, an azaphenyl group, a diazaphenyl group, an azanaphthyl group, or a diazanaphthyl group, and these groups may be substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group;
^X1 represents a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 1,4-naphthylene group, a 1,5-naphthylene group, a 2,6-naphthylene group, or a 2,7-naphthylene group;
^X2 represents a phenylene group, a naphthylene group, an azaphenylene group, a diazaphenylene group, an azanaphthylene group, or a diazanaphthylene group;
p represents 1 or 2;
However, when p is 2, two X ^1s may be the same or different;
q represents 0, 1 or 2;
However, when q is 2, two X ^{2 s} may be the same or different.

Hereinafter, the triazine compound represented by formula (1) may be referred to as triazine compound (1). The definitions of the substituents in triazine compound (1) and their preferred specific examples are as follows:

[Regarding Ar ¹ and Ar ² ]
^Ar1 and ^Ar2 each independently represent a phenyl group, a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, and these groups may be substituted with one or more substituents selected from the group consisting of a fluorine atom, a methyl group, and a cyano group.

Ar ¹ and Ar ² each independently represent, for example, a phenyl group, a p-tolyl group, an m-tolyl group, an o-tolyl group, a 2,4-dimethylphenyl group, a 3,5-dimethylphenyl group, a mesityl group, a 1-naphthyl group, a 2-naphthyl group, a biphenyl-2-yl group, a biphenyl-3-yl group, a biphenyl-4-yl group, a 3-methylbiphenyl-4-yl group, a 2'-methylbiphenyl-4-yl group, a 4'-methylbiphenyl-4-yl group, a 2,2'-dimethylbiphenyl-4-yl group, a 6-methylbiphenyl-3-yl group, a 5-methylbiphenyl group, -3-yl group, 2'-methylbiphenyl-3-yl group, 4'-methylbiphenyl-3-yl group, 6,2'-dimethylbiphenyl-3-yl group, 5-methylbiphenyl-2-yl group, 6-methylbiphenyl-2-yl group, 2'-methylbiphenyl-2-yl group, 4'-methylbiphenyl-2-yl group, 6,2'-dimethylbiphenyl-2-yl group, 4-fluorophenyl group, 3-fluorophenyl group, 2-fluorophenyl group, 4-cyanophenyl group, 3-cyanophenyl group, 2-cyanophenyl group, and the like.

In view of the excellent electron transport properties of the triazine compound (1), Ar ¹ and Ar ² are preferably each independently a phenyl group or a biphenylyl group, and more preferably a phenyl group or a 4-biphenylyl group.

[Regarding ^Ar3 ]
In formula (1), ^Ar3 represents a polycyclic aromatic group which may be substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group.

In terms of ease of synthesis of triazine compound (1), the polycyclic aromatic group is preferably a bicyclic, tricyclic, or tetracyclic polycyclic aromatic group, and more preferably a tricyclic or tetracyclic polycyclic aromatic group.

The polycyclic aromatic group is preferably a hydrocarbon aromatic group, a nitrogen-containing six-membered ring aromatic group, or a chalcogen-containing aromatic group, since triazine compound (1) contributes to the formation of a higher performance organic electroluminescent device.

Examples of aromatic hydrocarbon groups include naphthyl, phenanthryl, anthryl, pyrenyl, fluorenyl, benzofluorenyl, triphenylenyl, and fluoranthenyl groups. Because triazine compound (1) contributes to the formation of higher-performance organic electroluminescent devices, preferred aromatic hydrocarbon groups are phenanthryl, fluorenyl, anthryl, and triphenylenyl, with 9-phenanthryl, 9,9-dimethylfluoren-2-yl, and 2-triphenylenyl being more preferred.

Examples of nitrogen-containing aromatic groups include azanaphthyl, diazanaphthyl, benzo[b]quinolyl, benzo[c]quinolyl, benzo[f]quinolyl, benzo[g]quinolyl, benzo[h]quinolyl, phenazinyl, phenanthrolinyl, azapyrenyl, diazapyrenyl, azatriphenylenyl, and diazatriphenylenyl. In terms of ease of synthesis of triazine compound (1), the nitrogen-containing six-membered ring aromatic group is preferably an azanaphthyl or phenanthrolinyl group, more preferably a phenanthrolinyl group, and even more preferably a 1,10-phenanthrolinyl group.

Examples of chalcogen-containing aromatic groups include benzothiophenyl, benzofuranyl, dibenzothiophenyl, dibenzofuranyl, benzonaphthofuranyl, benzonaphthothiophenyl, xanthenyl, and benzoxanthenyl groups. In terms of ease of synthesis of triazine compound (1), the dibenzofuranyl group is preferred as the chalcogen-containing aromatic group.

[Regarding ^Ar4 ]
Ar ⁴ represents a phenyl group, an azaphenyl group, a diazaphenyl group, an azanaphthyl group, or a diazanaphthyl group, and these groups may be substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group.

Examples of the azaphenyl group, diazaphenyl group, azanaphthyl group, or diazanaphthyl group include a pyridyl group, a pyrazyl group, a pyrimidyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, a quinoxalinyl group, and a quinazolinyl group.

The triazine compound (1) contributes to the formation of a higher performance organic electroluminescent device, and therefore, Ar ⁴ is
a phenyl group, or
It is preferably an azaphenyl group which may be substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group.
More preferably, Ar ⁴ is a pyridyl group.

[Regarding ^X1 ]
^X1 represents a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 1,4-naphthylene group, a 1,5-naphthylene group, a 2,6-naphthylene group, or a 2,7-naphthylene group.

X ¹ is preferably a phenylene group, more preferably a 1,3-phenylene group or a 1,4-phenylene group, in that the triazine compound (1) contributes to the formation of a higher performance organic electroluminescent device.

[Regarding ^X2 ]
^X2 represents a phenylene group, a naphthylene group, an azaphenylene group, a diazaphenylene group, an azanaphthylene group, or a diazanaphthylene group.

Examples of ^X2 include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 2,3-pyridylene group, a 2,4-pyridylene group, a 2,5-pyridylene group, a 2,6-pyridylene group, a 2,4-pyrimidylene group, a 2,5-pyrimidylene group, a 2,5-pyrazylene group, a 1,2-naphthylene group, a 1,3-naphthylene group, a 1,4-naphthylene group, a 1,5-naphthylene group, a 1,6-naphthylene group, a 1,7-naphthylene group, a 1,8-naphthylene group, a 2,3-naphthylene group, a 2,4-naphthylene group, a 2,5-naphthylene group, a 2,6-naphthylene group, a 2,7-naphthylene group, and a 2,8-naphthylene group. Examples thereof include a quinolylene group, a 2,3-quinolylene group, a 2,4-quinolylene group, a 2,5-quinolylene group, a 2,6-quinolylene group, a 2,7-quinolylene group, a 2,8-quinolylene group, a 3,4-quinolylene group, a 3,5-quinolylene group, a 3,6-quinolylene group, a 3,7-quinolylene group, a 3,8-quinolylene group, a 4,5-quinolylene group, a 4,6-quinolylene group, a 4,7-quinolylene group, a 4,8-quinolylene group, a 5,8-quinolylene group, a 2,3-quinoxalylene group, a 2,5-quinoxalylene group, a 2,6-quinoxalylene group, a 2,4-quinazolylene group, a 2,5-quinazolylene group, and a 2,6-quinazolylene group.

^X2 is preferably a phenylene group, more preferably a 1,2-phenylene group or a 1,4-phenylene group, in that the triazine compound (1) contributes to the formation of a higher performance organic electroluminescent device.

[Regarding p]
p represents 1 or 2. However, when p is 2, two X ^1s may be the same or different.
It is more preferable that p is 1, since the triazine compound (1) contributes to the formation of an organic electroluminescent device with higher performance.

[Regarding q]
q represents 0, 1 or 2. However, when p is 2, two ^X2's may be the same or different.
It is more preferable that q is 0 or 1 in terms of ease of synthesis of the triazine compound (1).

[Preferred embodiment of triazine compound (1)]
Ar ¹ and Ar ² are phenyl groups;
^Ar3 is a 9-phenanthryl group;
^Ar4 is a 3-pyridyl group;
X ¹ is a 1,3-phenylene group or a 1,4-phenylene group,
q is 0,
It is preferred that p is 1.

[Specific examples of triazine compound (1)]
Specific examples of the triazine compound (1) include the following (1-1) to (1-93), but the present disclosure is not limited to these. As the triazine compound (1), the compound represented by 1-1 or 1-46 is preferred because of its excellent performance as an electron transport material in an organic electroluminescent device.

Next, a method for producing the triazine compound (1) will be described.
The triazine compound (1) can be produced by the method shown in the following synthetic route.
That is, a method for producing a triazine compound according to one embodiment of the present disclosure includes subjecting a triazine intermediate represented by formula (2) to a coupling reaction with a compound represented by formula (3) in the presence of a palladium catalyst:

During the ceremony,
Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , X ¹ , X ² , p and q have the same meanings as defined above;
Y represents a chlorine atom, a bromine atom, a trifluoromethanesulfonyloxy group, or an iodine atom;
M represents ZnZ ¹ , MgZ ² , Sn(Z ³ ) ₃ , or B(OZ ⁴ ) ₂ ;
^Z1 and ^Z2 each independently represent a chlorine atom, a bromine atom, or an iodine atom;
Z ³ may be the same or different and represent an alkyl group having 1 to 4 carbon atoms or a phenyl group, and three Z ³ may be the same or different;
Z ⁴ s may be the same or different and represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and two Z ^{4 s} may be the same or different. Two (OZ ⁴ ) groups may be bonded to form a ring together with the boron atom.

Among these, M is preferably B(OZ ⁴ ) ₂ in that the triazine compound (1) can be easily synthesized.

ZnZ ¹ and MgZ ² are not particularly limited, but examples thereof include ZnCl, ZnBr, ZnI, MgCl, MgBr, and MgI.
Sn(Z ³ ) ₃ is not particularly limited, but examples thereof include Sn(Me) ₃ and Sn(Bu) ₃ .
B(OZ ⁴ ) ₂ is not particularly limited, and examples thereof include B(OH) ₂ , B(OMe) ₂ , B(O ⁱ Pr) ₂ , B(OBu) ₂ , and B(OPh) ₂ . Here, Me represents a methyl group, ⁱ Pr represents an isopropyl group, Bu represents a butyl group, and Ph represents a phenyl group. Furthermore, examples of B(OZ ⁴ ) ₂ in which two (OZ ⁴ ) groups are united to form a ring with the boron atom are not particularly limited, and examples thereof include groups represented by the following (I) to (VI), with the group represented by (II) being preferred in terms of good yield.

The coupling reaction in the synthetic route is a step in which a triazine compound represented by formula (2) is reacted with a halogen compound represented by formula (3) in the presence of a palladium catalyst to produce triazine compound (1). The synthetic route can obtain the target product in good yield by applying reaction conditions for common coupling reactions such as the Suzuki-Miyaura reaction, Negishi reaction, Tamao-Kumada reaction, and Stille reaction. When applying the reaction conditions for the Suzuki-Miyaura reaction to the synthetic route, it is preferable to carry out the reaction in the presence of a base.
The triazine compound used in the coupling reaction can be produced, for example, according to the method disclosed in WO 2017/052259. Alternatively, commercially available products may be used.
The halogenated compound used in the coupling reaction can be produced, for example, according to Korean Patent Publication No. 2015/122343. Alternatively, commercially available products may be used. There are no particular restrictions on the molar equivalent of the halogenated compound used, but it is preferable to use 0.5 to 3.0 molar equivalents relative to the triazine compound in terms of achieving a good reaction yield.

Examples of the group represented by Y include a chlorine atom, a bromine atom, a trifluoromethanesulfonyloxy group, and an iodine atom. The trifluoromethanesulfonyloxy group is preferred because it provides a good yield of triazine compound (1).

Palladium catalysts that can be used in the synthesis route are not particularly limited, but specific examples include:
palladium salts such as palladium chloride, palladium acetate, palladium trifluoroacetate, and palladium nitrate;
Complex compounds such as π-allylpalladium chloride dimer, palladium acetylacetonate, tris(dibenzylideneacetone)dipalladium, bis(dibenzylideneacetone)palladium, dichlorobis(acetonitrile)palladium, and dichlorobis(benzonitrile)palladium; and
Palladium complexes having a tertiary phosphine as a ligand, such as dichlorobis(triphenylphosphine)palladium, tetrakis(triphenylphosphine)palladium, dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium, bis(tri-t-butylphosphine)palladium, bis(tricyclohexylphosphine)palladium, and dichlorobis(tricyclohexylphosphine)palladium;
Examples include:

Palladium complexes having a tertiary phosphine as a ligand can also be prepared in situ by adding a tertiary phosphine to a palladium salt or complex compound. Examples of tertiary phosphines that can be used in this case include triphenylphosphine, trimethylphosphine, tributylphosphine, tri(tert-butyl)phosphine, tricyclohexylphosphine, t-butyldiphenylphosphine, 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene, 2-(diphenylphosphino)-2'-(N,N-dimethylamino)biphenyl, 2-(di-t-butylphosphino)biphenyl, 2-(dicyclohexylphosphino)biphenyl, and bis(diphenylphosphine). Examples include 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, ...

Among these, palladium complexes having a tertiary phosphine as a ligand are preferred because of their high yield, and palladium complexes having 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl or triphenylphosphine as a ligand are more preferred.

The molar ratio of tertiary phosphine to palladium salt or complex compound is preferably in the range of 1:10 to 10:1, and more preferably in the range of 1:2 to 3:1 in terms of good yield. There is no limit to the amount of palladium catalyst used in the synthesis route, but in terms of good yield, the molar equivalent of the palladium catalyst is preferably in the range of 0.005 to 0.5 molar equivalents relative to the triazine compound.

The synthesis route may be carried out by adding a base. The base used is not particularly limited, but examples include metal hydroxide salts such as sodium hydroxide, potassium hydroxide, and calcium hydroxide; metal carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, and cesium carbonate; metal acetates such as potassium acetate and sodium acetate; metal phosphates such as potassium phosphate and sodium phosphate; metal fluoride salts such as sodium fluoride, potassium fluoride, and cesium fluoride; and metal alkoxides such as sodium methoxide, potassium methoxide, sodium ethoxide, potassium isopropyl oxide, and potassium tert-butoxide. Among these, metal carbonates or metal phosphates are preferred in terms of good reaction yield, with potassium carbonate or potassium phosphate being more preferred. There are no particular restrictions on the amount of base, but in terms of good reaction yield, the molar ratio of base to triazine compound is preferably in the range of 1:2 to 10:1, and more preferably in the range of 1:1 to 4:1.

The synthetic route can be carried out in a solvent, such as water; ethers such as diisopropyl ether, dibutyl ether, cyclopentyl methyl ether (CPME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, and dimethoxyethane; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, and tetralin; carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and 4-fluoroethylene carbonate; ethyl acetate, butyl acetate, methyl propionate, methyl propionate, methyl butyrate, and γ-lactoacetate. Examples of solvents include esters such as amines, amines, and the like; amides such as N,N-dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP); ureas such as N,N,N',N'-tetramethylurea (TMU) and N,N'-dimethylpropyleneurea (DMPU); dimethyl sulfoxide (DMSO); and alcohols such as methanol, ethanol, isopropyl alcohol, butanol, octanol, benzyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and 2,2,2-trifluoroethanol; and these may be mixed in any ratio. There are no particular restrictions on the amount of solvent used. Of these, water, ethers, amides, alcohols, or mixed solvents thereof are preferred in terms of good reaction yield, and a mixed solvent of THF and water is more preferred.

The synthesis route 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 40°C to 150°C in terms of good reaction yield.
The synthetic route can be obtained by carrying out the usual treatment after the completion of the reaction, and if necessary, purification can be carried out by recrystallization, column chromatography, sublimation, preparative HPLC, or the like.

Triazine compound (1) can be used, for example, in organic electronic devices such as organic electroluminescent devices and photoelectric devices.

<Materials for organic electroluminescent devices>
A material for organic electroluminescent devices according to one embodiment of the present disclosure contains a triazine compound (1).
The triazine compound (1) can be used, for example, as an electron transport material for organic electroluminescent devices. A material for organic electroluminescent devices containing the triazine compound (1) exhibits high luminous efficiency and long lifetime characteristics at a high level, and contributes to the production of organic electroluminescent devices that can be used for various applications.

<Organic electroluminescent device>
The organic electroluminescent device containing the triazine compound (1) will be described below.
The organic electroluminescent device contains a triazine compound (1).

The configuration of the organic electroluminescent device is not particularly limited, but examples thereof include the following configurations (i) to (v).
(i): anode/light-emitting layer/cathode (ii): anode/hole-transporting layer/light-emitting layer/cathode (iii): anode/light-emitting layer/electron-transporting layer/cathode (iv): anode/hole-transporting layer/light-emitting layer/electron-transporting layer/cathode (v): anode/hole-injection layer/hole-transporting layer/light-emitting layer/electron-transporting layer/electron-injection layer/cathode

Triazine compound (1) may be contained in any of the above layers, but in terms of achieving excellent light-emitting properties in the organic electroluminescent device, it is preferably contained in one or more layers selected from the group consisting of the light-emitting layer and the layer between the light-emitting layer and the cathode.

Therefore, in the configurations (i) to (v) above, it is preferable that triazine compound (1) be contained in one or more layers selected from the group consisting of the light-emitting layer, the electron-transporting layer, and the electron-injecting layer.

The organic electroluminescent device will be described in more detail below, taking the above configuration (v) as an example, with reference to Figure 1.

Note that although the organic electroluminescent element 100 shown in FIG. 1 has a so-called bottom-emission element configuration, organic electroluminescent elements are not limited to bottom-emission element configurations. In other words, organic electroluminescent elements may have other known element configurations, such as top-emission types.

Figure 1 is a schematic cross-sectional view showing an example of the layer structure of an organic electroluminescent device containing triazine compound (1).

The organic electroluminescent device 100 comprises, in this order, a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, an emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode 8. However, some of these layers may be omitted, or other layers may be added. For example, a hole blocking layer may be provided between the emitting layer 5 and the electron transport layer 6, or the hole injection layer 3 may be omitted and the hole transport layer 4 may be provided directly on the anode 2.

In addition, instead of the multiple layers, a single layer that combines the functions of multiple layers, such as an electron injection/transport layer that combines the functions of an electron injection layer and an electron transport layer, may be provided. Furthermore, for example, the single-layer hole transport layer 4 and the single-layer electron transport layer 6 may each be composed of multiple layers.

<<Layer containing triazine compound (1)>>

In the configuration example shown in FIG. 1, the organic electroluminescent device 100 contains a triazine compound (1) in one or more layers selected from the group consisting of the light-emitting layer 5, the electron transport layer 6, and the electron injection layer 7. It is preferable that the electron transport layer 6 contains the triazine compound (1). Note that the triazine compound (1) may be contained in multiple layers of the organic electroluminescent device.

The following describes an organic electroluminescent device 100 in which the electron transport layer 6 contains a triazine compound (1).

[Substrate 1]
The substrate 1 is not particularly limited as long as it is a substrate that is commonly used for the relevant portion by those skilled in the art, and examples thereof include a glass plate, a quartz plate, a plastic plate, a plastic film, etc. Among these, a glass plate, a quartz plate, and a light-transmitting plastic film are preferred.

Examples of light-transmitting plastic films include films made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), etc.

In addition, when the light is extracted from the substrate 1 side, the substrate 1 is transparent to the wavelength of the emitted light.

[Anode 2]
An anode 2 is provided on the substrate 1 (on the hole injection layer 3 side).

Examples of anode materials include metals, alloys, electrically conductive compounds, and mixtures thereof, each having a large work function (for example, 4 eV or more). Specific examples of anode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

In the case of organic electroluminescent devices in which light is extracted through the anode, the anode is formed from a conductive transparent material that is transparent or substantially transparent to the light emitted.

[Hole injection layer 3, hole transport layer 4]
Between the anode 2 and the light-emitting layer 5, a hole injection layer 3 and a hole transport layer 4 are provided in this order from the anode 2 side.

The hole injection layer 3 and hole transport layer 4 function to transport holes injected from the anode to the light-emitting layer. By placing these hole injection layer 3 and hole transport layer 4 between the anode 2 and the light-emitting layer 5, more holes can be injected into the light-emitting layer 5 with a lower electric field.

The hole injection layer 3 and the hole transport layer 4 also function as electron blocking layers. That is, electrons injected from the cathode 8 and transported from the electron injection layer 7 and/or the electron transport layer 6 to the light-emitting layer 5 are prevented from leaking into the hole injection layer 3 and/or the hole transport layer 4 by the electron barrier present at the interface between the light-emitting layer 5 and the hole injection layer 3 and/or the hole transport layer 4. As a result, the electrons accumulate at the interface within the light-emitting layer 5, resulting in effects such as improved light-emitting efficiency and an organic electroluminescent device with excellent light-emitting performance.

The materials for the hole injection layer 3 and the hole transport layer 4 have at least one of the following properties: hole injection, hole transport, and electron barrier properties. The materials for the hole injection layer 3 and the hole transport layer 4 may be either organic compounds or inorganic substances.

Specific examples of materials for the hole injection layer 3 and the hole transport layer 4 include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers (particularly thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds.

Among these, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferred because of the good performance of the organic electroluminescent device, with aromatic tertiary amine compounds being particularly preferred.

Specific examples of aromatic tertiary amine compounds and styrylamine compounds include N,N,N',N'-tetraphenyl-4,4'-diaminophenyl, N,N'-diphenyl-N,N'-bis(m-tolyl)-[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'- Examples include di(4-methoxyphenyl)-4,4'-diaminobiphenyl, N,N,N',N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis(diphenylamino)quadriphenyl, N,N,N-tri(p-tolyl)amine, 4-(di-p-tolylamino)-4'-[4-(di-p-tolylamino)styryl]stilbene, 4-N,N-diphenylamino-(2-diphenylvinyl)benzene, 3-methoxy-4'-N,N-diphenylaminostilbenzene, N-phenylcarbazole, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD), and 4,4',4''-tris[N-(m-tolyl)-N-phenylamino]triphenylamine (MTDATA).

Inorganic compounds such as p-type Si and p-type SiC can also be cited as examples of materials for the hole injection layer 3 and hole transport layer 4.

The hole injection layer 3 and the hole transport layer 4 may have a single structure made of one or more materials, or may have a laminate structure made of multiple layers of the same or different compositions.

[Light-emitting layer 5]
The light-emitting layer 5 is provided between the hole transport layer 4 and the electron transport layer 6 .

Materials for the light-emitting layer 5, i.e., light-emitting materials, include phosphorescent materials, fluorescent materials, and thermally activated delayed fluorescent materials. Electron-hole pairs recombine in the light-emitting layer 5, resulting in light emission.

The light-emitting layer 5 may consist of a single small molecule material or a single polymer material, but more commonly consists of a host material doped with a guest compound. Light emission comes primarily from the dopant and can be of any color.

Examples of host materials include compounds having a biphenylyl group, a fluorenyl group, a triphenylsilyl group, a carbazole group, a pyrenyl group, or an anthryl group. More specific examples include DPVBi (4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl), BCzVBi (4,4'-bis(9-ethyl-3-carbazovinylene)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), 2-(9-phenylcarbazol-3-yl)-9-[4-(4-phenylphenylquinazolin-2-yl)carbazole], 9,10-bis(biphenyl)anthracene, and the like.

Examples of fluorescent dopants include anthracene, pyrene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, quinacridone, dicyanomethylenepyran compounds, thiopyran compounds, polymethine compounds, pyrylium, thiapyrylium compounds, fluorene derivatives, periflanthene derivatives, indenoperylene derivatives, bis(azinyl)amine boron compounds, bis(azinyl)methane compounds, carbostyril compounds, boron compounds, and cyclic amine compounds. The fluorescent dopant may be a combination of two or more selected from these.

Phosphorescent dopants include, for example, metal complexes of iridium, platinum, palladium, osmium, etc.

Specific examples of fluorescent dopants and phosphorescent dopants include Alq3 (tris(8-hydroxyquinoline)aluminum), DPAVBi (4,4'-bis[4-(di-p-tolylamino)styryl]biphenyl), perylene, bis[2-(4-n-hexylphenyl)quinoline](acetylacetonate)iridium(III), Ir(PPy) ₃ (tris(2-phenylpyridine)iridium(III)), FIrPic (bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III))), and the like.

Furthermore, the luminescent material is not limited to being contained only in the luminescent layer 5. For example, the luminescent material may be contained in a layer adjacent to the luminescent layer 5 (the hole transport layer 4 or the electron transport layer 6). This can further increase the luminous efficiency of the organic electroluminescent element 100.

The light-emitting layer 5 may have a single-layer structure made of one or more materials, or a laminate structure made of multiple layers of the same or different compositions.

[Electron transport layer 6]
An electron transport layer 6 is provided between the light emitting layer 5 and the electron injection layer 7 .

The electron transport layer 6 functions to transport electrons injected from the cathode 8 to the light-emitting layer. By interposing the electron transport layer 7 between the cathode 8 and the light-emitting layer 5, electrons are injected into the light-emitting layer 5 at a lower electric field.

As described above, the electron transport layer 6 preferably contains triazine compound (1). Furthermore, in addition to triazine compound (1), the electron transport layer 6 may further contain one or more types selected from conventionally known electron transport materials.

When triazine compound (1) is not contained in the electron transport layer 6 but is contained in another layer, one or more electron transport materials selected from conventionally known electron transport materials can be used as the electron transport material constituting the electron transport layer 6.

Conventionally known electron transport materials include alkali metal compounds, alkaline earth metal compounds, transition metal compounds, zinc group element compounds, and earth metal compounds. Examples of alkali metal compounds, alkaline earth metal compounds, transition metal compounds, zinc group element compounds, and earth metal compounds include 8-hydroxyquinolinatolithium (Liq), bis(8-hydroxyquinolinato)zinc, bis(8-hydroxyquinolinato)copper, bis(8-hydroxyquinolinato)manganese, tris(8-hydroxyquinolinato)aluminum, tris(2-methyl-8-hydroxyquinolinato)aluminum, and tris(8-hydroxyquinolinato). Examples of chelate aryloxides include bis(2-methyl-8-quinolinato)gallium, bis(10-hydroxybenzo[h]quinolinato)beryllium, bis(10-hydroxybenzo[h]quinolinato)zinc, bis(2-methyl-8-quinolinato)chlorogallium, bis(2-methyl-8-quinolinato)(o-cresolate)gallium, bis(2-methyl-8-quinolinato)-1-naphtholatoaluminum, and bis(2-methyl-8-quinolinato)-2-naphtholatogallium.

The electron transport layer 6 may have a single layer structure made of one or more materials, or a laminate structure made of multiple layers of the same or different compositions.

The organic electroluminescent device 100 may be provided with an electron injection layer 7 to improve electron injection properties and device characteristics (e.g., luminous efficiency, low-voltage driving, or high durability).

[Electron injection layer 7]
An electron injection layer 7 is provided between the electron transport layer 6 and the cathode 8. The electron injection layer 7 has a function of transferring electrons injected from the cathode to the light-emitting layer 5. By providing the electron injection layer between the cathode 8 and the light-emitting layer 5, electrons are injected into the light-emitting layer 5 at a lower electric field.

Examples of materials for the electron injection layer 7 include organic compounds such as fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylene tetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane, and anthrone.

Further, examples of materials for the electron injection layer 7 include inorganic compounds such as various oxides, fluorides, nitrides, and oxynitrides, such as _SiO2 , AlO, SiN, SiON, AlON, GeO, LiO, LiON, TiO, TiON, TaO, TaON, TaN, LiF, C, and Yb.

[Cathode 8]
A cathode 8 is provided on the electron injection layer 7. In the case of an organic electroluminescence element configured so that only light emitted through the anode 8 is extracted, the cathode 8 can be formed from any conductive material.

Examples of materials for the cathode 8 include metals with a low work function (hereinafter also referred to as electron-injecting metals), alloys, electrically conductive compounds, and mixtures thereof. Here, a metal with a low work function is, for example, a metal with a work function of 4 eV or less.

Specific examples of materials for the cathode 8 include sodium, sodium-potassium alloy, magnesium, lithium, a magnesium/copper mixture, a magnesium/silver mixture, a magnesium/aluminum mixture, a magnesium/indium mixture, an aluminum/aluminum oxide (Al ₂ O ₃ ) mixture, indium, a lithium/aluminum mixture, and rare earth metals.

Among these, from the viewpoints of electron injection properties and durability against oxidation, etc., mixtures of an electron injection metal and a second metal that has a larger and more stable work function than the electron injection metal, such as magnesium/silver mixtures, magnesium/aluminum mixtures, magnesium/indium mixtures, aluminum/aluminum oxide (Al ₂ O ₃ ) mixtures, and lithium/aluminum mixtures, are preferred.

[Method of forming each layer]
Each layer except for the electrodes (anode and cathode) described above can be formed by forming a thin film using a known method such as vacuum deposition, spin coating, casting, LB (Langmuir-Blodgett) method, etc. The material for each layer may be used alone or, if necessary, together with a material such as a binder resin or a solvent.

There are no particular restrictions on the film thickness of each layer formed in this way and it can be selected appropriately depending on the situation, but it is usually in the range of 5 nm to 5 μm.

The anode 1 and cathode 8 can be formed by thinning the electrode material using methods such as vapor deposition or sputtering. A pattern can be formed using a mask of the desired shape during vapor deposition or sputtering, or a thin film can be formed by vapor deposition or sputtering, and then a pattern of the desired shape can be formed using photolithography or other methods.

The film thickness of the anode 1 and cathode 8 is preferably 1 μm or less, and more preferably 10 nm or more and 200 nm or less.

When forming a layer containing triazine compound (1), it may be used in combination with the above-mentioned conventionally known electron transport material. Therefore, for example, triazine compound (1) and a conventionally known electron transport material may be co-deposited, or a layer of a conventionally known electron transport material may be laminated on a layer of triazine compound (1).

Organic electroluminescent devices can be used as a type of lamp for illumination or as an exposure light source, or as a projection device that projects images onto a screen, or as a display device that displays still or moving images directly.

When organic electroluminescent elements are used as display devices for video playback, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Furthermore, by using two or more types of organic electroluminescent elements that emit different colors, it is possible to create a full-color display device.

When used as an electron transport layer, triazine compound (1) can provide an organic electroluminescent device that has significantly superior driving voltage and luminous efficiency compared to conventionally known triazine compounds.

This is expected to improve the driving stability and luminous efficiency of organic electroluminescent devices. Furthermore, due to its distinctive skeleton, triazine compound (1) has high chemical stability, which can contribute to extending the life of organic electroluminescent devices.

By using triazine compound (1) as an electron transport layer in an organic electroluminescent device, it is possible to provide a triazine compound that can achieve high levels of low-voltage operation, high efficiency, and long life for the device. Furthermore, it is possible to provide an organic electroluminescent device that can achieve high levels of high efficiency and long life using triazine compound (1).

The present disclosure will be explained in more detail below based on examples, but the present disclosure should not be construed as being limited in any way by these examples. Commercially available reagents were used.

[ ¹ H-NMR measurement]
¹ H-NMR measurements were performed using a Bruker ASCEND 400 (400 MHz; manufactured by BRUKER) or a Bruker ULTRASHIELD Plus 400 (400 MHz; manufactured by BRUKER). ¹ H-NMR measurements were performed using deuterated chloroform (CDCl ₃ ) or deuterated dimethyl sulfoxide (DMSO-d ₆ ) as the measurement solvent and tetramethylsilane (TMS) as the internal standard.

[Measurement of luminescence characteristics]
The light-emitting characteristics of the organic electroluminescent device were evaluated by applying a direct current to the device prepared in each example (described later) in an environment of 25°C using a luminance meter BM-9 (product name, manufactured by Topcon Technohouse Corporation).

Synthesis Example 1

Under an argon atmosphere, 3-(9-phenanthryl)-5-(3-pyridyl)phenyl trifluoromethanesulfonate (4.99 g, 10 mmol), 2,4-diphenyl-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine (3.48 g, 8.0 mmol), palladium acetate (54 mg, 0.24 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (229 mg, 0.48 mmol) were dissolved in tetrahydrofuran (80 mL). To this was added 2M aqueous potassium carbonate solution (12 mL), and the mixture was stirred at 80°C for 24 hours. After allowing to cool to room temperature, water and methanol were added, the mixture was suspended, and the mixture was filtered. The residue was washed with water and methanol to obtain a crude product. The crude product was dissolved in chloroform, activated carbon was added, and the mixture was stirred for 30 minutes. The activated carbon was removed by filtration through Celite, and the solvent was then distilled off under reduced pressure. The resulting solid was purified by recrystallization (toluene) to yield a white solid of 2-[3'-(phenanthren-9-yl)-5'-(pyridin-3-yl)-(1,1'-biphenyl)-4-yl]-4,6-diphenyl-1,3,5-triazine (compound 1-1) (3.81 g, 75%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 9.04 (d, J = 1.7, 1H), 8.90 (d, J = 8.5Hz, 2H), 8.76-8.85 (m, 6H), 8.67 (dd, J = 4.8, 1.6Hz, 1H), 8.04-8.07 (m, 2H), 8.01 (t , J=1.7Hz, 1H), 7.93-7.97 (m, 4H), 7.85 (s, 1H), 7.83 (t, J=1.6Hz, 1H), 7.70-7.75 (m, 2H), 7.57-7.68 (m, 8H), 7.42-7.46 (m, 1H).

Synthesis Example 2

Under an argon atmosphere, 2,4-biphenylyl-6-{3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl}-1,3,5-triazine (3.50 g, 8.0 mmol), 3-(9-phenanthryl)-5-(3-pyridyl)phenyl trifluoromethanesulfonic acid (4.60 g, 9.6 mmol), palladium acetate (54 mg, 0.24 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (228 mg, 0.48 mmol) were suspended in THF (80 mL). To this suspension was added 2M aqueous potassium carbonate solution (12 mL), and the mixture was heated to reflux for 15 hours. After allowing to cool to room temperature, water and methanol were added to the reaction mixture, and the precipitated solid was collected by filtration. The resulting solid was purified by silica gel column chromatography (hexane/chloroform) followed by recrystallization (toluene) to obtain the desired 2-[3'-(phenanthren-9-yl)-5'-(pyridin-3-yl)-(1,1'-biphenyl)-3-yl]-4,6-diphenyl-1,3,5-triazine (compound 1-46) (4.10 g, 80%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 9.10 (t, J=1.6Hz, 1H), 9.05 (dd, J=2.4, 0.7Hz, 1H), 8.82-8.85 (m, 2H), 8.76-8.80 (m, 5H), 8.66 (dd, J=1.6, 4.8Hz, 1H), 8.13 (dd, J=8.2, 1.0Hz, 1H), 8.07 (ddd, J=7.9, 2.3, 1. 7Hz, 1H), 8.02 (t, J = 1.7Hz, 1H), 7.99 (t, J = 1.6Hz, 1H), 7.95-7.98 (m, 2H), 7.87 (s, 1H), 7.8 5 (t, J=1.6Hz, 1H), 7.66-7.76 (m, 3H), 7.55-7.65 (m, 8H), 7.44 (ddd, J=8.0, 4.8, 0.7Hz, 1H).

Reference example-1

Under an argon atmosphere, 3-bromo-5-chlorophenol (10.0 g, 48 mmol), 9-phenanthreneboronic acid (15.0 g, 68 mmol), and tetrakis(triphenylphosphine)palladium (1.67 g, 1.4 mmol) were suspended in 1,4-dioxane (100 mL). 5M aqueous sodium hydroxide solution (29 mL) was added to this suspension, and the mixture was stirred at 100°C for 16 hours. Water and chloroform were added to the reaction mixture. The organic layer was separated, and sodium sulfate was added to it. The sodium sulfate was filtered off, and the filtrate was evaporated to dryness under reduced pressure. The resulting crude product was purified by silica gel column chromatography (chloroform/ethyl acetate = 20/1) to obtain the desired 3-chloro-5-(phenanthrene-9-yl)phenol as a brown solid (14.2 g, 97%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 8.77 (d, J=8.2Hz, 1H), 8.72 (d, J=8.2Hz, 1H), 7.88-7.91 (m, 2H), 7.60-7.71 (m, 4H), 7. 54-7.58 (m, 1H), 7.12 (t, J=1.7Hz, 1H), 6.96 (t, J=1.7Hz, 1H), 6.89-6.91 (m, 1H), 5.28 (brs, 1H).

Reference example-2

Under an argon atmosphere, 3-chloro-5-(9-phenanthryl)phenol (6.60 g, 22 mmol), bis(pinacolato)diboron (11.0 g, 43 mmol), tris(dibenzylideneacetone)dipalladium (496 mg, 0.54 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (1.03 g, 2.2 mmol), and potassium acetate (8.50 g, 87 mmol) were suspended in dioxane (216 mL) and stirred at 110°C for 24 hours. After allowing to cool, the resulting mixture was extracted with chloroform and washed with saturated brine. The organic layer was concentrated and then purified by silica gel column chromatography to obtain a white solid of 3-(phenanthren-9-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol (yield: 8.50 g, 99%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 8.70-8.77 (m, 2H), 7.86-7.93 (m, 2H), 7.51-7.69 (m, 6H), 7.3 4 (dd, J=2.6, 0.8Hz, 1H), 7.12-7.14 (m, 1H), 4.95 (s, 1H), 1.35 (s, 12H).

Reference example-3

Under an argon atmosphere, 3-(phenanthren-9-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol (8.50 g, 21 mmol), 3-bromopyridine (3.1 mL, 32 mmol), and tetrakis(triphenylphosphine)palladium (496 mg, 0.43 mmol) were dissolved in tetrahydrofuran (214 mL). 2M aqueous sodium carbonate solution (43 mL) was added, and the mixture was stirred at 80°C overnight. After cooling to room temperature, chloroform was added to form a suspension, and the mixture was filtered. The residue was washed with water, methanol, and chloroform to obtain a white solid of 3-(phenanthren-9-yl)-5-(pyridin-3-yl)phenol (6.30 g, 85%).

^1H -NMR (DMSO- _d6 ) δ (ppm): 9.96 (br, 1H), 8.87-8.96 (m, 3H), 8.58 (dd, J = 4.7, 1.5Hz, 1H), 8.12 (dt, J = 8.0, 1.9Hz, 1H), 8.05 (d, J = 7.8, 1H), 7.97 (d, J = 7.4, 1H), 7.88 (s, 1H), 7.63-7.77 (m, 4H), 7.47-7.51 (m, 1H), 7.30 (s, 1H), 7.21 (t, J = 1.9Hz, 1H), 7.00 (s, 1H).

Reference example-3

Under an argon atmosphere, 3-(9-phenanthryl)-5-(3-pyridyl)phenol (6.30 g, 18 mmol) and pyridine (2.9 mL) were dissolved in dichloromethane (36 mL), and trifluoromethanesulfonic anhydride (3.6 mL, 21 mmol) was added dropwise thereto and stirred at room temperature overnight. After the reaction was complete, the resulting mixture was extracted with chloroform and washed with water and saturated brine. The organic layer was concentrated and purified by silica gel chromatography to obtain a white solid of 3-(9-phenanthryl)-5-(3-pyridyl)phenyltrifluoromethanesulfonic acid (6.7 g, 77%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 8.92 (d, J = 2.4, 1H), 8.82 (d, J = 8.2Hz, 1H), 8.75 (d, J = 7. 9Hz, 1H), 8.68 (dd, J=4.8, 1.6Hz, 1H), 7.92-7.96 (m, 2H), 7.87 (d, J = 8.2Hz, 1H), 7.81 (t, J = 1.5Hz, 1H), 7.70-7.74 (m, 3H), 7.64-7.68 (m, 1H), 7.58-7.62 (m, 2H), 7.52-7.53 (m, 1H), 7.41-7.45 (m, 1H).

Reference example-4

4,6-Diphenyl-2-[5-(9-phenanthryl)-3-(3-pyridyl)phenyl]-1,3,5-triazine (ETL-1) was synthesized by the method described in Example 6 of JP-A-2011-63584.
¹ H-NMR (CDCl ₃ ) δ (ppm): 9.22 (s, 1H), 9.14 (s, 1H), 9.13 (d, J = 5.4Hz, 1H), 8.89 (d, J = 8.4Hz, 1H), 8.83 (d, J = 8.4Hz, 1H), 8.80 (d, J = 7.1Hz, 4H), 8.60 (d, J = 8.1Hz, 1H), 8.0 5 (s, 1H), 8.02 (d, J = 7.1Hz, 1H), 7.96 (d, J = 8.1Hz, 1H), 7.90 (brt, J = 6.5Hz, 1 H), 7.90 (s, 1H), 7.76-7.80 (m, 2H), 7.72 (t, J=7.0Hz, 1H), 7.59-7.67 (m, 8H). ．．

The resulting compound was then used for device evaluation.

[Evaluation as Electron Transport Layer 6]
Element Example 1 (see Figure 2)
(Preparation of substrate 1 and anode 2)
A glass substrate with an indium-tin oxide (ITO) transparent electrode, on which a 2 mm wide striped pattern of an ITO film (thickness: 110 nm) was prepared, was used as the substrate 1 having an anode 2 on its surface. The substrate was then washed with isopropyl alcohol and then subjected to surface treatment by ozone ultraviolet cleaning.

(Preparation for vacuum deposition)
After cleaning, each layer was deposited on the surface-treated substrate by vacuum deposition using a vacuum deposition method, and each layer was laminated.
First, the glass substrate was placed in a vacuum deposition chamber and the pressure was reduced to 1.0×10 ⁻⁴ Pa. Then, each layer was formed in the following order according to the film formation conditions. Each organic material was formed by resistance heating.

(Fabrication of Hole Injection Layer 3)
Sublimation-purified N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine and 1,2,3-tris[(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane were mixed in a mass ratio of 99:1 to form a 10 nm film, to produce hole injection 3. The film formation rate was 0.1 nm/sec.

(Fabrication of First Hole Transport Layer 41)
Sublimation-purified N-[1,1′-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine was deposited at a rate of 0.2 nm/sec to a thickness of 85 nm to form a first hole transport layer 41.

(Fabrication of Second Hole Transport Layer 42)
Sublimation-purified N-phenyl-N-(9,9-diphenylfluoren-2-yl)-N-(1,1′-biphenyl-4-yl)amine was deposited at a rate of 0.15 nm/sec to form a film of 5 nm, thereby forming a second hole transport layer 42 .

(Fabrication of Light-Emitting Layer 5)
Sublimation-purified 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tertbutylphenyl)]amino-bisbenzofurano-9,9′-spirofluorene were mixed in a mass ratio of 95:5 to form a 20 nm film, thereby producing the light-emitting layer 5. The film formation rate was 0.1 nm/sec.

(Fabrication of Hole Blocking Layer 9)
Sublimation-purified 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)[1,1'-biphenyl]-3-yl]-4,6-diphenyl-1,3,5-triazine was deposited at a rate of 0.05 nm/sec to form a 6 nm thick film as a hole blocking layer 9 .

(Preparation of Electron Transport Layer 6)
2-[3'-(phenanthren-9-yl)-5'-(pyridin-3-yl)-(1,1'-biphenyl)-4-yl]-4,6-diphenyl-1,3,5-triazine (compound 1-1) synthesized in Synthesis Example 1 and 8-hydroxyquinolinolatolithium (hereinafter referred to as Liq) were mixed in a mass ratio of 50:50 to form a 25 nm film, thereby producing an electron transport layer 6. The film formation rate was 0.15 nm/sec.

(Fabrication of Electron Injection Layer 7)
Liq was deposited at a rate of 0.02 nm/sec to a thickness of 2 nm to form an electron injection layer 7 .

(Fabrication of Cathode 8)
Finally, a metal mask was placed perpendicular to the ITO stripes (anode 2) on the substrate 1, and a cathode 8 was formed. The cathode had a two-layer structure, with silver/magnesium (mass ratio 1/10) and silver deposited in this order to thicknesses of 80 nm and 20 nm, respectively. The silver/magnesium deposition rate was 0.5 nm/sec, and the silver deposition rate was 0.2 nm/sec.

As a result of the above, an organic electroluminescent device 100 having a light-emitting area of 4 mm ² was produced as shown in Figure 2. The thickness of each film was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).
The device was then sealed in a nitrogen atmosphere glove box with oxygen and moisture concentrations of 1 ppm or less by sealing the glass sealing cap and the film-formed substrate (device) with bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

Element Example 2
An organic electroluminescent device was produced in the same manner as in Element Example 1, except that in Element Example 1, a 25 nm film (film formation rate: 0.15 nm/sec) of Compound A-49 and Liq was formed in a mass ratio of 50:50 as the electron transport layer 6 instead of a 25 nm film (film formation rate: 0.15 nm/sec) of 2-[3′-(phenanthren-9-yl)-5′-(pyridin-3-yl)-(1,1′-biphenyl)-3-yl]-4,6-diphenyl-1,3,5-triazine (Compound 1-46) synthesized in Synthesis Example 2 and Liq in a mass ratio of 50:50.
Element Reference Example 1

An organic electroluminescent device was fabricated in the same manner as in Device Example 1, except that, instead of depositing a 25 nm film (film deposition rate: 0.15 nm/sec) of 2-[3'-(phenanthren-9-yl)-5'-(pyridin-3-yl)-(1,1'-biphenyl)-4-yl]-4,6-diphenyl-1,3,5-triazine (compound 1-1) and Liq in a 50:50 (mass ratio) ratio, a 25 nm film (film deposition rate: 0.15 nm/sec) of ETL-1 and Liq was deposited in a 50:50 (mass ratio) ratio for electron transport layer 6.

A direct current was applied to the fabricated organic electroluminescent device, and the light-emitting characteristics were evaluated according to the method described above for measuring light-emitting characteristics.

As the light-emitting characteristics, the current efficiency (cd/A) when a current density of 10 mA/ ^cm2 was applied was measured, and the element lifetime during continuous lighting was also measured. The element lifetime was determined by measuring the luminance decay time during continuous lighting when driven at an initial luminance of 1000 cd/ ^m2 , and measuring the time required for the luminance (cd/ ^m2 ) to decrease by 5%. The current efficiency (cd/A) and lifetime values were expressed as relative values when the value of Element Reference Example-1 was taken as 100. The results are shown in Table 1.

1. Substrate 2. Anode 3. Hole injection layer 4. Hole transport layer 5. Light-emitting layer 6. Electron transport layer 7. Electron injection layer 8. Cathode 9. Hole blocking layer 51. First hole transport layer 52. Second hole transport layer 100. Organic electroluminescent element

Claims (2)

Triazine compounds represented by formula (1):
During the ceremony,
Ar ¹ and Ar ² each independently represent a phenyl group, a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted with one or more substituents selected from the group consisting of a fluorine atom, a methyl group, and a cyano group;
^Ar3 represents a polycyclic aromatic group optionally substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group;
^Ar4 represents a pyridyl group ;
^X1 represents a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 1,4-naphthylene group, a 1,5-naphthylene group, a 2,6-naphthylene group, or a 2,7-naphthylene group;
^X2 represents a phenylene group, a naphthylene group, an azaphenylene group, a diazaphenylene group, an azanaphthylene group, or a diazanaphthylene group;
p represents 1 or 2;
However, when p is 2, two X ^1s may be the same or different;
q represents 0, 1 or 2;
However, when q is 2, two X ^{2 s} may be the same or different. Ar ¹ and Ar ² are phenyl groups;
^Ar3 is a 9-phenanthryl group;
^Ar4 is a 3-pyridyl group;
X ¹ is a 1,3-phenylene group or a 1,4-phenylene group,
q is 0,
The triazine compound of claim 1 , wherein p is 1.