JP7577935B2 - Cyclic Azine Compounds - Google Patents

Description

The present invention relates to a cyclic azine compound, a material for an organic electroluminescent device, and an electron transport material for an organic electroluminescent device.

Organic electroluminescent devices are used not only for small displays but also for large televisions, lighting, and the like, and their development is being actively pursued.
For example, Patent Document 1 discloses a heterocyclic compound that, as a material for an organic electroluminescent device, contributes to providing an organic electroluminescent device having excellent efficiency, low driving voltage and/or excellent life characteristics.

Korean Patent Publication No. 10-2017-0089408

In recent years, market demands for organic electroluminescent devices have become increasingly high, and materials with even better luminous efficiency/external quantum efficiency are being sought.
Here, although the organic electroluminescent device using the heterocyclic compound disclosed in Patent Document 1 exhibits excellent luminous efficiency, further improvement is required.

One aspect of the present invention aims to provide a cyclic azine compound that contributes to the fabrication of an organic electroluminescent device with high luminous efficiency/external quantum efficiency, as well as a material for an organic electroluminescent device and an electron transport material for an organic electroluminescent device that contain the cyclic azine compound.

The cyclic azine compound according to one embodiment of the present invention is a cyclic azine compound represented by formula (1):

In formula (1),
R ¹ to R ¹⁰ each independently represent
Hydrogen atoms,
an alkyl group having 1 to 12 carbon atoms,
a cycloalkyl group having 3 to 20 carbon atoms,
Cyano group,
a phenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 1-naphthyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 2-naphthyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 2-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 3-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group, or
a 4-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
L ¹ and L ² each independently represent a single bond, 1,3-phenylene, 1,4-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, 3,3'-biphenylene, 4,4'-biphenylene, 3,4'-biphenylene, or 4,3'-biphenylene;
Py is a group represented by formula (2);

In formula (2),
R ¹¹ to R ¹⁴ each independently represent a single bond bonded to L ² , a hydrogen atom, a methyl group, a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenyl group, a 3-biphenyl group, or a 4-biphenyl group;
One of R ¹¹ to R ¹⁴ is a single bond bonding to L ² .

A material for an organic electroluminescent device according to another embodiment of the present invention contains the above cyclic azine compound.
An electron transport material for an organic electroluminescent device according to still another embodiment of the present invention contains the above cyclic azine compound.

According to one aspect of the present invention, it is possible to provide a cyclic azine compound that contributes to the production of an organic electroluminescent device having high luminous efficiency/external quantum efficiency, as well as a material for an organic electroluminescent device and an electron transport material for an organic electroluminescent device that contain the cyclic azine compound.

FIG. 1 is a schematic cross-sectional view showing an example of a layered structure of an organic electroluminescent device containing a cyclic azine compound according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing another example (Element Example 1) of the layered structure of an organic electroluminescent element containing a cyclic azine compound according to one embodiment of the present invention.

Hereinafter, a cyclic azine compound according to one embodiment of the present invention will be described in detail.
<Cyclic Azine Compounds>
A cyclic azine compound according to one embodiment of the present invention (hereinafter also referred to as "cyclic azine compound (1)") is a cyclic azine compound represented by formula (1):

In formula (1),
R ¹ to R ¹⁰ each independently represent
Hydrogen atoms,
an alkyl group having 1 to 12 carbon atoms,
a cycloalkyl group having 3 to 20 carbon atoms,
Cyano group,
a phenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 1-naphthyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 2-naphthyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 2-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 3-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group, or
a 4-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
L ¹ and L ² each independently represent a single bond, 1,3-phenylene, 1,4-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, 3,3'-biphenylene, 4,4'-biphenylene, 3,4'-biphenylene, or 4,3'-biphenylene;
Py is a group represented by formula (2);

In formula (2),
R ¹¹ to R ¹⁴ each independently represent a single bond bonded to L ² , a hydrogen atom, a methyl group, a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenyl group, a 3-biphenyl group, or a 4-biphenyl group;
One of R ¹¹ to R ¹⁴ is a single bond bonding to L ² .

When the cyclic azine compound (1) is used as a part of the components of an organic electroluminescent device (OLED; organic light emitting diode), the effect of improving the efficiency of luminous efficiency/external quantum efficiency can be obtained. In particular, this effect is more pronounced when the cyclic azine compound (1) is used as an electron transport layer.

Specific examples of the group represented by Py include the following (2-1) to (2-33).

[Specific examples of cyclic azine compound (1)]
Among the cyclic azine compounds according to one embodiment of the present invention represented by formula (1), specific examples of particularly preferred compounds include the following (1-1) to (1-80), but the cyclic azine compounds according to one embodiment of the present invention are not limited thereto.

Among these, cyclic azine compounds represented by formula (1-1), (1-10), (1-11), (1-24), (1-39), (1-69), (1-70), or (1-73) are preferred.

Next, a method for producing the cyclic azine compound (1) will be described.
The cyclic azine compound (1) can be prepared by the methods shown in the following synthetic pathways (i) to (V).

In formulas (3) to (13),
The definitions of R ¹ to R ¹⁰ are the same as those of R ¹ to R ¹⁰ in formula (1);
Y ¹ to Y ⁴ each independently represent a halogen atom or an OTf group (trifluoromethylsulfonyl group);
The definitions of ^L1 and ^L2 are the same as those of ^L1 and ^L2 in formula (1);
Py is defined as Py in formula (1);
R ²¹ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group;
The two R ²¹ in B(OR ²¹ ) ₂ may be the same or different;
Two OR ²¹ and the boron atom may form a ring.

Examples of the halogen atom represented by Y ¹ to Y ⁴ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, with a chlorine atom or a bromine atom being preferred in terms of the yield of the cyclic azine compound (1).

Examples of B( ^OR21 ) ₂ include B(OH) ₂ , B(OMe) ₂ , B(OiPr) ₂ , B(OBu) ₂ , and B(OPh) ₂ , where Me is a methyl group, iPr is an isopropyl group, Bu is a butyl group, and Ph is a phenyl group.

Examples of B(OR ²¹ ) ₂ in which two OR ²¹ and a boron atom form a ring include groups represented by the following formulae (I) to (VI), and the group represented by formula (II) is preferred in terms of good yield.

The coupling reactions in synthetic pathways (i) to (V) are methods in which an aryl halide compound represented by formula (4), (5), (7), (8), (11) or (12) is reacted with a boron compound represented by formula (3), (6), (9), (10) or (13) in the presence of a palladium catalyst and a base, and general Suzuki-Miyaura reaction conditions can be applied.

The boron compound can be produced, for example, according to the method disclosed in The Journal of Organic Chemistry, Vol. 60, p. 7508, 1995, or The Journal of Organic Chemistry, Vol. 65, p. 164, 2000.

The aryl halide can be produced, for example, according to Journal of the American Chemical Society, Vol. 74, p. 6289, 1952, or Synlett, p. 808, 2002. Commercially available products may also be used. It is preferable to use 0.5 to 3.0 molar equivalents of the aryl halide relative to the boron compound, as this provides a good reaction yield.

The boronation reaction in the synthetic routes (i) and (ii) is a method of producing a boron compound represented by formula (6) by reacting an aryl halide compound represented by formula (5) with a boron source (e.g., pinacolato borane, bis-pinacolato diboron, etc.) in the presence of a palladium catalyst and a base. These boron compounds can be produced, for example, according to the method disclosed in The Journal of Organic Chemistry, Vol. 60, p. 7508, 1995, or Tetrahedron Letters, Vol. 38, p. 3447, 1997.

Examples of palladium catalysts used in the above-mentioned coupling reaction and boronization reaction include palladium salts such as palladium chloride, palladium acetate, palladium trifluoroacetate, and palladium nitrate. Further examples include 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 tertiary phosphines as ligands such as dichlorobis(triphenylphosphine)palladium, tetrakis(triphenylphosphine)palladium, dichloro(1,1'-bis(diphenylphosphino)ferrocene)palladium, bis(tri-tert-butylphosphine)palladium, bis(tricyclohexylphosphine)palladium, and dichlorobis(tricyclohexylphosphine)palladium. These can also be prepared in the reaction system by adding a tertiary phosphine to a palladium salt or complex compound.

Examples of tertiary phosphines 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(diphenylphosphine), bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,1'-bis(diphenylphosphino)ferrocene, tri(2-furyl)phosphine, tri(o-tolyl)phosphine, tris(2,5-xylyl)phosphine, (±)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, etc.

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

The molar ratio of the tertiary phosphine to the 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 above-mentioned coupling reaction and boronation reaction, but in terms of good yield, it is preferable that the molar equivalent of the palladium catalyst is in the range of 0.005 to 0.5 molar equivalents relative to the boron compound.

Examples of bases used in the above-mentioned coupling reaction and boronization reaction include metal hydroxide salts such as sodium hydroxide, potassium hydroxide, calcium hydroxide, etc.; metal carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate, etc.; metal acetates such as potassium acetate, sodium acetate, etc.; metal phosphates such as potassium phosphate, sodium phosphate, etc.; metal fluoride salts such as sodium fluoride, potassium fluoride, cesium fluoride, etc.; and metal alkoxides such as sodium methoxide, potassium methoxide, sodium ethoxide, potassium isopropyl oxide, potassium tert-butoxide, etc., in terms of good reaction yield. Among these, metal carbonates or metal phosphates are preferred, and potassium carbonate or potassium phosphate is more preferred. There are no particular limitations on the amount of base used. In terms of good reaction yield, the molar ratio of the base to the boron 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 above-mentioned coupling reaction and boronization reaction can be carried out in a solvent.

Solvents include ethers such as water, 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, ethyl propionate, methyl butyrate, and gamma butyl acetate. -lactones and other esters; 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); alcohols such as dimethylsulfoxide (DMSO), methanol, ethanol, isopropyl alcohol, butanol, octanol, benzyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and 2,2,2-trifluoroethanol; and the like. These may be used alone or in any ratio. There is no particular limit to the amount of solvent used. Among these, water, ethers, amides, alcohols, and mixed solvents thereof are preferred in terms of good reaction yield, and a mixed solvent of THF and water, or a mixed solvent of toluene and 1-butanol is more preferred.

The above-mentioned coupling reaction and boronization reaction 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 60°C to 160°C in terms of good reaction yield.

After the above-mentioned coupling reaction and boronization reaction are completed, the desired product can be obtained by appropriately combining common purification processes such as recrystallization, column chromatography, sublimation purification, and preparative HPLC as necessary.

The uses of the cyclic azine compound (1) will be described below.
<Material for organic electroluminescence device, electron transport material for organic electroluminescence device>
The cyclic azine compound (1) can be used, for example, as a material for an organic electroluminescent device. The cyclic azine compound (1) can be used, for example, as an electron transport material for an organic electroluminescent device.
That is, the material for organic electroluminescence elements according to one embodiment of the present invention contains the cyclic azine compound (1). Also, the electron transport material for organic electroluminescence elements according to one embodiment of the present invention contains the cyclic azine compound (1). The material for organic electroluminescence elements and the electron transport material for organic electroluminescence elements containing the cyclic azine compound (1) contribute to the production of organic electroluminescence elements having high luminous efficiency/external quantum efficiency.

<Organic electroluminescent device>
The organic electroluminescent device according to one aspect of the present invention contains a cyclic azine compound (1).

The structure of the organic electroluminescent device is not particularly limited, but examples thereof include the following structures (i) to (vi).
(i): anode/light-emitting layer/cathode (ii): anode/hole-transport layer/light-emitting layer/cathode (iii): anode/light-emitting layer/electron-transport layer/cathode (iv): anode/hole-transport layer/light-emitting layer/electron-transport layer/cathode (v): anode/hole-injection layer/hole-transport layer/light-emitting layer/electron-transport layer/electron injection layer/cathode (vi): anode/hole-injection layer/charge-generation layer/hole-transport layer/light-emitting layer/electron-transport layer/cathode An organic electroluminescent device according to one embodiment of the present invention will now be described in more detail with reference to FIG. 1 , taking the configuration of (vi) as an example.

FIG. 1 is a schematic cross-sectional view showing an example of a layered structure of an organic electroluminescent device containing a cyclic azine compound according to one embodiment of the present invention.
1 has a so-called bottom emission type element configuration, the organic electroluminescence element according to one embodiment of the present invention is not limited to the bottom emission type element configuration. That is, the organic electroluminescence element according to one embodiment of the present invention may have a top emission type element configuration or another known element configuration.

The organic electroluminescent device 100 comprises a substrate 1, an anode 2, a hole injection layer 3, a charge generation layer 4, a hole transport layer 5, a light emitting layer 6, an electron transport layer 7, and a cathode 8 in this order. However, some of these layers may be omitted, or other layers may be added. For example, an electron injection layer may be provided between the electron transport layer 7 and the cathode 8, or the charge generation layer 4 may be omitted and the hole transport layer 5 may be provided directly on the hole injection layer 3. In addition, a single layer having the functions of multiple layers, such as an electron injection/transport layer having the functions of both the electron injection layer and the electron transport layer in a single layer, may be provided instead of the multiple layers. Furthermore, for example, the single-layer hole transport layer 5 and the single-layer electron transport layer 7 may each be made up of multiple layers.

[Layer containing a cyclic azine compound represented by formula (1)]
The organic electroluminescent device contains the cyclic azine compound represented by the above formula (1) 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. Thus, in the configuration example shown in Fig. 1, the organic electroluminescent device 100 contains the cyclic azine compound (1) in at least one layer selected from the group consisting of the light-emitting layer 6 and the electron transport layer 7. In particular, it is preferable that the electron transport layer 7 contains the cyclic azine compound (1). The cyclic azine compound (1) may be contained in multiple layers of the organic electroluminescent device, and when an electron injection layer is provided between the electron transport layer and the cathode, the electron injection layer may contain the cyclic azine compound (1).
In the following, an organic electroluminescent device 100 in which the electron transport layer 7 contains the cyclic azine compound (1) will be described.

[Substrate 1]
The substrate is not particularly limited, and examples thereof include a glass plate, a quartz plate, a plastic plate, a plastic film, etc. In the case of a configuration in which light emission is extracted from the substrate 1 side, the substrate 1 is transparent to the wavelength of light.
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), and the like.

[Anode 2]
An anode 2 is provided on the substrate 1 (on the side of the hole injection layer 3).
In the case of an organic electroluminescent device in which light is emitted through the anode, the anode is formed from a material that is transparent or substantially transparent to the emitted light.
The transparent material used for the anode is not particularly limited, but examples thereof include indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide, aluminum-doped tin oxide, magnesium-indium oxide, nickel-tungsten oxide, other metal oxides, metal nitrides such as gallium nitride, metal selenides such as zinc selenide, and metal sulfides such as zinc sulfide.
In the case of an organic electroluminescent device in which light is extracted only from the cathode side, the transmittance characteristics of the anode are not important. Therefore, examples of materials that can be used for the anode in this case include gold, iridium, molybdenum, palladium, platinum, etc.
A buffer layer (electrode interface layer) may be provided on the anode.

[Hole injection layer 3, hole transport layer 5]
Between the anode 2 and a light-emitting layer 6 described later, a hole injection layer 3, a charge generation layer 4 described later, and a hole transport layer 5 are provided in this order from the anode 2 side.
The hole injection layer and the hole transport layer have the function of transporting holes injected from the anode to the light-emitting layer. By interposing this hole injection layer and hole transport layer between the anode and the light-emitting layer, a large number of holes can be injected into the light-emitting layer with a lower electric field.

The hole injection layer and the hole transport layer also function as electron barrier layers. That is, electrons injected from the cathode and transported from the electron injection layer and/or the electron transport layer to the light-emitting layer are prevented from leaking to the hole injection layer and/or the hole transport layer due to the electron barrier present at the interface between the light-emitting layer and the hole injection layer and/or the hole transport layer. As a result, the electrons are accumulated at the interface within the light-emitting layer, which brings about effects such as improved light-emitting efficiency, and an organic electroluminescent element with excellent light-emitting performance is obtained.

The material for the hole injection layer and the hole transport layer has at least one of hole injection property, hole transport property, and electron barrier property. The material for the hole injection layer and the hole transport layer may be either organic or inorganic.

Specific examples of materials for the hole injection layer and hole transport layer 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-based 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, and aromatic tertiary amine compounds are 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(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine (TPD), 2,2-bis(4-di-p-tolylaminophenyl)propane, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl, 1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane, bis(4-dimethylamino-2-methylphenyl)phenylmethane, bis(4-di-p-tolylaminophenyl)phenylmethane, N,N'-diphenyl-N,N'- 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-diphenylaminostilbene, N-phenylcarbazole, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA), etc.

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

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

[Charge Generation Layer 4]
A charge generating layer 4 may be provided between the hole injection layer 3 and the hole transport layer 5 .
The material for the charge generating layer is not particularly limited, but may be, for example, dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN).
The charge generating layer may have a single layer 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 6]
The light-emitting layer 6 is provided between the hole transport layer 5 and the electron transport layer 7 described below.

Materials for the light-emitting layer include phosphorescent materials, fluorescent materials, and thermally activated delayed fluorescent materials. In the light-emitting layer, electron-hole pairs recombine, resulting in light emission.

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

Examples of host materials include compounds having a biphenyl group, a fluorenyl group, a triphenylsilyl group, a carbazole group, a pyrenyl group, and an anthryl group. More specifically, examples of the compound include DPVBi (4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl), BCzVBi (4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl), TBADN (2-tertiarybutyl-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, and the like. The fluorescent dopant may be a combination of two or more selected from these.

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

Specific examples of fluorescent 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)), and FIrPic (bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III))).

The light-emitting material is not limited to being contained only in the light-emitting layer. For example, the light-emitting material may be contained in a layer adjacent to the light-emitting layer (hole transport layer 5 or electron transport layer 7). This can further increase the luminous efficiency/external quantum efficiency of the organic electroluminescent device.

The light-emitting layer may be 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 7]
An electron transport layer 7 is provided between the light emitting layer 6 and a cathode 8 which will be described later.
The electron transport layer has a function of transporting electrons injected from the cathode to the light emitting layer. By interposing the electron transport layer between the cathode and the light emitting layer, electrons are injected into the light emitting layer at a lower electric field.

As described above, the electron transport layer preferably contains the cyclic azine compound (1).
The electron transport layer may further contain a conventionally known electron transport material in addition to the cyclic azine compound (1).
In addition, when the cyclic azine compound (1) is not contained in the electron transport layer but is contained in another layer, one or more types selected from conventionally known electron transport materials can be used as the electron transport material constituting the electron transport layer.

Examples of conventionally known electron transport materials include 8-hydroxyquinolinato lithium (Liq), bis(8-hydroxyquinolinato) zinc, bis(8-hydroxyquinolinato) copper, bis(8-hydroxyquinolinato) manganese, tris(8-hydroxyquinolinato) aluminum, tris(2-methyl-8-hydroxyquinolinato) aluminum, tris(8-hydroxyquinolinato) 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, and bis(2-methyl-8-quinolinato)-1-naphtholate. Aluminum, or bis(2-methyl-8-quinolinate)-2-naphtholate gallium, 2-[3-(9-phenanthrenyl)-5-(3-pyridinyl)phenyl]-4,6-diphenyl-1,3,5-triazine, and 2-(4,''-di-2-pyridinyl[1,1':3',1''-terphenyl]-5-yl)-4,6-diphenyl-1,3,5-triazine, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), BAlq (bis(2-methyl-8-quinolinate)-4-(phenylphenolate)aluminum), and bis(10-hydroxybenzo[h]quinolinate)beryllium).

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

When the electron transport layer has a two-layer structure with a first electron transport layer on the light-emitting layer side and a second electron transport layer on the cathode side, it is preferable that the first electron transport layer contains a cyclic azine compound (1).

[Cathode 8]
A cathode 8 is provided on the electron transport layer 7 .
In the case of an organic electroluminescent device in which only light emitted through the anode is extracted, the cathode can be made of any conductive material.

Cathode materials include sodium, sodium-potassium alloys, magnesium, lithium, magnesium/copper mixtures, magnesium/silver mixtures, magnesium/aluminum mixtures, magnesium/indium mixtures, aluminum/aluminum oxide (Al ₂ O ₃ ) mixtures, indium, lithium/aluminum mixtures, rare earth metals, and the like.

A buffer layer (electrode interface layer) may be provided on the cathode (electron transport layer side).

[Method of forming each layer]
Each layer except for the electrodes (anode and cathode) described above can be formed by forming a thin film from the material of each layer (together with a material such as a binder resin and a solvent, if necessary) by a known method such as a vacuum deposition method, a spin coating method, a casting method, or a Langmuir-Blodgett method (LB method).
There is no particular restriction on the thickness of each layer thus formed, and it can be appropriately selected depending on the circumstances, but it is usually in the range of 5 nm to 5 μm.

The anode and cathode can be formed by forming a thin film of an electrode material by a method such as vapor deposition, sputtering, etc. A pattern may be formed through a mask having a desired shape during vapor deposition or sputtering, or a pattern having a desired shape may be formed by photolithography after forming a thin film by vapor deposition, sputtering, etc.
The film thickness of the anode and cathode is preferably 1 μm or less, and more preferably 10 nm or more and 200 nm or less.

The organic electroluminescent device according to one embodiment of the present invention may be used as a kind of lamp for illumination or exposure light source, or as a projection device for projecting an image, or as a display device for directly viewing still images or moving images. When used as a display device for playing moving images, the driving method may be either a passive matrix method or an active matrix method. In addition, by using two or more kinds of organic electroluminescent devices according to this embodiment having different emission colors, a full-color display device can be produced.
The cyclic azine compound according to one embodiment of the present invention can be synthesized by appropriately combining known reactions (for example, Suzuki-Miyaura cross-coupling reaction, etc.).

According to the above aspect of the present invention, it is possible to provide an organic electroluminescent device with high luminous efficiency/external quantum efficiency.

The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited in any way by these examples.

[ ¹ H-NMR measurement]
¹ H-NMR measurements were carried out using Gemini 200 (Varian).
[Glass transition temperature measurement]
The glass transition temperature was measured using a DSC7020 (manufactured by Hitachi High-Tech Science Corporation).

[Synthesis Example 1]

Under a nitrogen atmosphere, 3-bromo-2,6-lutidine (12.0 g, 64.5 mmol) was dissolved in cyclopentyl methyl ether (dehydrated) (130 ml) and cooled in a dry ice-ethanol bath. 1.55 M n-butyllithium (49.9 ml) was slowly dripped into this solution, and after the dripping was completed, the mixture was stirred for an additional 30 minutes, and (N,N,N',N'-tetramethylethylenediamine)zinc(II) dichloride (19.5 g) was added. After stirring for 30 minutes at room temperature, 1-bromo-4-iodobenzene (23.7 g) and bis(triphenylphosphine)palladium(II) dichloride (1.4 g) were added and the mixture was heated and stirred at 70°C for 2 hours. After cooling to room temperature, toluene was added and the mixture was suction filtered to remove insoluble matter. The resulting solution was evaporated under reduced pressure, purified by silica gel column chromatography (eluent: toluene/ethyl acetate = 4/1), and then recrystallized from hexane to obtain 3-(4-bromophenyl)-2,6-dimethylpyridine (9.1 g).

2,4-Diphenyl-6-[4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-naphthalene]phenyl]-1,3,5-triazine (6.0 g) and 3-(4-bromophenyl)-2,6-dimethylpyridine (3.4 g) were dissolved in THF (61 ml). 2.0 M-tripotassium phosphate aqueous solution (19 ml) and tetrakis(triphenylphosphine)palladium(0) (0.37 g) were added thereto, and the mixture was heated and stirred at 70°C for 20 hours. After cooling to room temperature, water was added and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and ethanol, then dissolved in toluene (150 mL), activated carbon (500 mg) was added, and the mixture was heated and stirred at 110°C for 1.5 hours. The activated carbon was filtered off by suction filtration using a Kiriyama funnel covered with Celite, and the filtrate was distilled under reduced pressure. The obtained solid was recrystallized from toluene to obtain a white solid of compound (1-1) (yield: 3.9 g, 54%).
¹ H-NMR (CDCl ₃ ) δ (ppm): 8.95 (d, 2H), 8.84 (d, 4H), 8.07 (m, 2H), 7.79 (d, 2H), 7.45-7.65 (m, 15H), 7.11 (d, 1H), 2.71 (s, 6H)

[Synthesis Example 2]

2-[4-(4-chloro-1-naphthalenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (7.6 g) and 2-methyl-6-phenyl-4-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-phenyl]-pyridine (7.2 g) were dissolved in THF (158 ml). 2.0 M-tripotassium phosphate aqueous solution (25 ml), palladium acetate (0.11 g) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (X-Phos) (0.46 g) were added thereto, and the mixture was heated and stirred at 70°C for 14.5 hours. After cooling to room temperature, water was added and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and acetone, and then dissolved in toluene (600 mL), activated carbon (1 g) was added, and the mixture was heated and stirred at 100° C. for 2 hours. The activated carbon was separated by suction filtration using a Kiriyama funnel lined with Celite, and the filtrate was distilled under reduced pressure. The obtained solid was washed with acetone to obtain a white solid of compound (1-69) (yield: 5.3 g, 48%).
¹ H-NMR (CDCl ₃ ) δ (ppm): 8.95 (d, 2H), 8.84 (d, 4H), 8.05 (m, 4H), 7.89 (s, 1H), 7.80 (m, 4H) 7.57-7.69 (m, 10H), 7.45-7.55 (m, 4H), 7.42 (m, 2H), 2 .74 (s, 3H)

[Synthesis Example 3]

2,4-Diphenyl-6-[4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-naphthalene]phenyl]-1,3,5-triazine (9.0 g) and 3-bromo-2-methyl-6-(1-naphthyl)-pyridine (5.3 g) were dissolved in THF (160 ml). 2.0 M-tripotassium phosphate aqueous solution (25 ml) and tetrakis(triphenylphosphine)palladium(0) (0.37 g) were added thereto, and the mixture was heated and stirred at 70°C for 40 hours. After cooling to room temperature, the solvent was distilled off and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and ethanol, then dissolved in chlorobenzene (300 mL), activated carbon (1.3 g) was added, and the mixture was heated and stirred at 100°C for 2 hours. The activated carbon was removed by suction filtration using a Kiriyama funnel lined with Celite, and the filtrate was distilled off under reduced pressure. The resulting solid was recrystallized from chlorobenzene to obtain a white solid of compound (1-10) (yield: 6.1 g, 58%). The glass transition temperature (Tg) was 106°C.
¹ H-NMR (CDCl ₃ ) δ (ppm): 8.96 (d, 2H), 8.85 (m, 4H), 8.29 (m, 1H), 8.10 (m, 1H), 7.96 (m, 2H), 7.82 (d, 2H), 7.77 (m, 2H), 7,50-7.73 (m, 15H), 2.49 ( s, 3H)

[Synthesis Example 4]

2,4-Diphenyl-6-[4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-naphthalene]phenyl]-1,3,5-triazine (10.0 g) and 3-bromo-2-methyl-6-(2-naphthyl)-pyridine (5.8 g) were dissolved in THF (178 ml). 2.0 M-tripotassium phosphate aqueous solution (27 ml) and tetrakis(triphenylphosphine)palladium(0) (0.60 g) were added thereto, and the mixture was heated and stirred at 70°C for 30.5 hours. After cooling to room temperature, water was added and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and ethanol, then dissolved in chlorobenzene (300 mL), activated carbon (1.3 g) was added, and the mixture was heated and stirred at 140°C for 2 hours. The activated carbon was removed by suction filtration using a Kiriyama funnel lined with Celite, and the filtrate was distilled off under reduced pressure. The resulting solid was recrystallized from toluene to obtain a white solid of compound (1-11) (yield: 8.5 g, 73%). The glass transition temperature (Tg) was 121°C.
¹ H-NMR (CDCl ₃ ) δ (ppm): 8.96 (d, 2H), 8.85 (m, 4H), 8.63 (m, 1H), 8.29 (d, 1H), 8.09 (m, 1H), 8.01 (m, 2H), 7.86-7.95 (m, 2H), 7.81 (d, 2H), 7.75 (d, 1H), 7,58-7.69 (m, 8H), 7.46-7.58 (m, 5H), 2.50 (s, 3H)

[Synthesis Example 5]

2,4-Diphenyl-6-[4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-naphthalene]phenyl]-1,3,5-triazine (10.0 g) and 6-(2,6-dimethylpyridin-3-yl)naphthalen-2-yl trifluoromethanesulfonate (10.2 g) were dissolved in THF (178 ml). 2.0 M-tripotassium phosphate aqueous solution (27 ml) and tetrakis(triphenylphosphine)palladium(0) (0.42 g) were added thereto, and the mixture was heated and stirred at 70°C for 7 hours. After cooling to room temperature, water was added and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and ethanol, then dissolved in toluene (300 mL), activated carbon (2 g) was added, and the mixture was heated and stirred at 120°C for 2 hours. The activated carbon was removed by suction filtration using a Kiriyama funnel lined with Celite, and the filtrate was distilled off under reduced pressure. The solid obtained was recrystallized from toluene to obtain a white solid of compound (1-70) (yield: 9.6 g, 81%). The glass transition temperature (Tg) was 116°C.
¹ H-NMR (CDCl ₃ ) δ (ppm): 8.95 (d, 2H), 8.84 (d, 4H), 7.96-8.12 (m, 5H), 7.88 (m, 1H), 7.80 (d, 2H), 7.76 (m, 1H), 7.46-7.68 (m, 12H), 7,13 (d, 1H) ), 2.64 (s, 3H), 2.60 (s, 3H)

[Synthesis Example 6]

2,4-Diphenyl-6-[4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-naphthalene]phenyl]-1,3,5-triazine (10.0 g) and 4-(bromophenyl)-2,6-dimethylpyridine (5.1 g) were dissolved in THF (178 ml). To this was added 2.0 M potassium carbonate aqueous solution (27 ml) and tetrakis(triphenylphosphine)palladium(0) (0.42 g), and the mixture was heated and stirred at 70°C for 64.5 hours. After cooling to room temperature, water was added and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and ethanol, then dissolved in toluene (300 mL), activated carbon (1.1 g) was added, and the mixture was heated and stirred at 120°C for 2 hours. The activated carbon was filtered off by suction filtration using a Kiriyama funnel covered with Celite, and the filtrate was distilled under reduced pressure. The resulting solid was recrystallized from toluene to obtain a white solid of compound (1-24) (yield: 7.0 g, 64%). The glass transition temperature (Tg) was 112° C.
¹ H-NMR (CDCl ₃ ) δ (ppm): 8.94 (d, 2H), 8.83 (m, 4H), 8.00-8.11 (m, 2H), 7.75-7.83 (m, 4H), 7.47-7.71 (m, 12H), 7.31 (br, 2H), 2.65 (s, 6H)

[Synthesis Example 7]

2-Chloro-4,6-di(biphenyl-4-yl)-1,3,5-triazine (3.0 g) and 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-naphthyl-2,6-dimethyl-3-pyridine (2.8 g) were dissolved in THF (71 ml). To this was added 2.0 M potassium carbonate aqueous solution (11 ml) and tetrakis(triphenylphosphine)palladium(0) (0.17 g), and the mixture was heated and stirred at 70°C for 17.5 hours. After cooling to room temperature, water was added and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and ethanol, then dissolved in toluene (150 mL), activated carbon (1 g) was added, and the mixture was heated and stirred at 120°C for 2 hours. The activated carbon was filtered off by suction filtration using a Kiriyama funnel covered with Celite, and the filtrate was distilled under reduced pressure. The obtained solid was dissolved in toluene (30 ml) and reprecipitated by adding normal butanol (30 ml) to obtain a white solid of compound (1-39) (yield: 3.8 g, 86%). The glass transition temperature (Tg) was 114° C.
¹ H-NMR (CDCl ₃ ) δ (ppm): 9.22 (d, 1H), 8.89 (d, 4H), 8.57 (d, 1H), 7.84 (d, 4H), 7.73 (m, 4H) 7.68 (m, 1H), 7.48-7.61 (m, 8H), 7.43 (m, 2H), 7.18 (d , 1H), 2.69 (s, 3H), 2.34 (s, 3H)

[Synthesis Example 8]

2-Chloro-4,6-di(biphenyl-4-yl)-1,3,5-triazine (2.2 g) and 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-naphthyl-2,6-dimethyl-4-pyridine (2.8 g) were dissolved in THF (47 ml). To this was added 2.0 M potassium carbonate aqueous solution (8 ml) and tetrakis(triphenylphosphine)palladium(0) (0.18 g), and the mixture was heated and stirred at 70°C for 48 hours. After cooling to room temperature, water was added and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and acetone, dissolved in toluene (100 mL), activated carbon (0.5 g) was added, and the mixture was heated and stirred at 100°C for 2 hours. The activated carbon was filtered off by suction filtration using a Kiriyama funnel covered with Celite, and the filtrate was distilled under reduced pressure. The resulting solid was recrystallized from toluene (25 ml) to obtain compound (1-73) as a white solid (yield: 2.8 g, 87%). The glass transition temperature (Tg) was 111° C.
¹ H-NMR (CDCl ₃ ) δ (ppm): 9.20 (d, 1H), 8.87 (d, 4H), 8.53 (d, 1H), 7.94 (d, 1H), 7.83 (d, 4H) 7.66-7.75 (m, 5H), 7.55-7.60 (m, 2H), 7.48-7.54 (m , 4H), 7.40-7.46 (m, 2H), 7,16 (br, 2H) 2.67 (s, 6H)

Next, the element evaluation will be described.
[Element Example 1 (see FIG. 2)]

(Preparation of Substrate 101 and Anode 102)
A glass substrate with an indium tin oxide (ITO) transparent electrode, on which a 2 mm wide ITO film (thickness: 110 nm) was patterned in stripes, was prepared as a substrate having an anode 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 and surface treatment, each layer was deposited by vacuum deposition on the substrate by vacuum deposition, so that 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 prepared according to the film formation conditions in the following order.

(Fabrication of Hole Injection Layer 103)
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 formed into a film of 55 nm at a rate of 0.15 nm/sec to prepare a hole injection layer.

(Preparation of First Hole Transport Layer 1051)
A 10 nm thick film of N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine was formed at a rate of 0.15 nm/sec to prepare a first hole transport layer.

(Preparation of second hole transport layer 1052)
A film of N-phenyl-N-(9,9-diphenylfluoren-2-yl)-N-(1,1'-biphenyl-4-yl)amine was formed to a thickness of 10 nm at a rate of 0.15 nm/sec to prepare a second hole transport layer.

(Fabrication of Light-Emitting Layer 106)
A 25 nm thick film was formed by mixing 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tertbutylphenyl)]amino-bisbenzofurano-9,9′-spirofluorene in a ratio of 95:5 (mass ratio) to prepare a light-emitting layer. The film formation rate was 0.18 nm/sec.

(Preparation of First Electron Transport Layer 1071)
A film of 4,6-diphenyl-2-(3′-(9,9-dimethyl-9H-fluoren-2-yl)-1,1′-biphenyl-3-yl)-1,3,5-triazine was formed to a thickness of 5 nm at a rate of 0.15 nm/sec to form a first electron transport layer 71 .

(Preparation of second electron transport layer 1072)
The sublimation-purified compound (1-1) and 8-hydroxyquinolinolatolithium (hereinafter, Liq) were mixed in a ratio of 50:50 (mass ratio) to form a 25 nm film, thereby producing a second electron transport layer 71. The film formation rate was 0.15 nm/sec.

(Fabrication of cathode 108)
Finally, a metal mask was placed so as to be perpendicular to the ITO stripes on the substrate, and the cathode 8 was formed. The cathode had a two-layer structure in which silver/magnesium (mass ratio 1/10) and silver were formed in this order to thicknesses of 80 nm and 20 nm, respectively. The film formation rate of silver/magnesium was 0.5 nm/sec, and the film formation rate of silver was 0.2 nm/sec.

In this manner, an organic electroluminescent device 100 having a light-emitting area ^{of 4} mm2 was produced as shown in Fig. 2. The thickness of each film was measured using a stylus film thickness meter (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. The glass sealing cap and the film-formed substrate (device) were sealed using bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

A direct current was applied to the organic electroluminescent device prepared as described above, and the light emission characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse). As the light emission characteristics, the external quantum efficiency (%) was measured when a current density of 10 mA/ ^cm2 was applied. The external quantum yield is defined as the ratio of the number of photons actually emitted outside the device per unit time to the current flowing through the device, i.e., the number of electrons flowing through the device per unit time. The measurement results obtained are shown in Table 1.

[Element Example 2]
An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that the compound (1-69) synthesized in Synthesis Example 2 was used instead of the compound (1-1) in Element Example 1. The measurement results are shown in Table 1.

[Element Example 3]
An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that the compound (1-11) synthesized in Synthesis Example 4 was used instead of the compound (1-1) in Element Example 1. The measurement results obtained are shown in Table 1.

[Element Example 4]
An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that the compound (1-24) synthesized in Synthesis Example 6 was used instead of the compound (1-1) in Element Example 1. The measurement results are shown in Table 1.

[Element Example 5]
An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that the compound (1-39) synthesized in Synthesis Example 7 was used instead of the compound (1-1) in Element Example 1. The measurement results are shown in Table 1.

[Reference element example 1]
An organic electroluminescent device was prepared and evaluated in the same manner as in Element Example-1, except that the compound 4,6-diphenyl-2-[4-[4-[4-(3-pyridinyl)phenyl]-1-naphthalenyl]phenyl]-1,3,5-triazine (compound ETL-1) disclosed in Korean Patent Publication No. 10-2017-0089408 was used in Element Example-1. The obtained measurement results are shown in Table 1.

According to Device Example 1, an organic electroluminescent device was obtained that exhibited an extremely superior external quantum efficiency compared to Device Reference Example 1.
Therefore, the cyclic azine compound according to one aspect of the present invention can be used as a material for an organic electroluminescence element and an electron transport material for an organic electroluminescence element, which contribute to the fabrication of an organic electroluminescence element having high luminous efficiency/external quantum efficiency. Furthermore, the cyclic azine compound according to one aspect of the present invention can provide an organic electroluminescence element having high luminous efficiency/external quantum efficiency.

1,101 Substrate 2,102 Anode 3,103 Hole injection layer
4 Charge generation layer 5, 105 Hole transport layer 6, 106 Light emitting layer 7, 107 Electron transport layer 8, 108 Cathode 51, 1051 First hole transport layer 52, 1052 Second hole transport layer 71, 1071 First electron transport layer 72, 1072 Second electron transport layer
100 Organic electroluminescent device

Claims (8)

A cyclic azine compound represented by formula (1):

In formula (1),
R ¹ to R ¹⁰ each independently represent
Hydrogen atoms,
an alkyl group having 1 to 12 carbon atoms,
a cycloalkyl group having 3 to 20 carbon atoms,
Cyano group,
a phenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 1-naphthyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 2-naphthyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 2-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
a 3-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group, or
a 4-biphenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group;
L ¹ and L ² each independently represent a single bond, 1,3-phenylene, 1,4-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, 3,3'-biphenylene, 4,4'-biphenylene, 3,4'-biphenylene, or 4,3'-biphenylene;
Py is represented by formula (2-1), (2-9), (2-27), or (2-28).

R ¹ to R ¹⁰ each independently represent
Hydrogen atoms,
an alkyl group having 1 to 12 carbon atoms,
a cycloalkyl group having 3 to 20 carbon atoms,
a cyano group, or
2. The cyclic azine compound according to claim 1, which is a phenyl group which may be substituted with an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or a cyano group. R ¹ to R ¹⁰ each independently represent
2. The cyclic azine compound according to claim 1, wherein the aryl group is a hydrogen atom or a phenyl group. ^L1 is 1,3-phenylene, 1,4-phenylene, naphthalene-1,4-diyl, or naphthalene-2,6-diyl;
The cyclic azine compound according to any one of claims 1 to 3, wherein ^L2 is a single bond, 1,3-phenylene, 1,4-phenylene, naphthalene-1,4-diyl, or naphthalene-2,6-diyl. The cyclic azine compound according to claim 1, represented by formula (1-1):

The cyclic azine compound according to claim 1, represented by formula (1-11), (1-24), (1-39), (1-69), (1-70), or (1-73):

A material for an organic electroluminescent device comprising the cyclic azine compound according to any one of claims 1 to 6. An electron transport material for organic electroluminescent devices comprising the cyclic azine compound according to any one of claims 1 to 6.

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