Novel adamantane compound and organic electroluminescent device containing the compound

Abstract

To provide a novel adamantane compound, and an organic electric field element excellent in heat resistance and excellent in longevity or luminous efficacy.SOLUTION: The invention provides an adamantane compound represented by general formula (1). In the formula, G represents a C4-30 aromatic group with at least one group-16 element; Ar1 to Ar3 each represent a substituted / unsubstituted C6-24 aromatic hydrocarbon group or the like; Ad represents a 1-adamantyl group or 2-adamantyl group; and Z1 to Z3 each independently represent a nitrogen atom or C-H.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a cyclic azine compound having a novel adamantyl group and an organic electroluminescent device containing the same.

[0002] Conventional organic electroluminescent devices have a higher driving voltage, lower emission luminance and emission efficiency, and significantly lower device lifetime compared to inorganic light-emitting diodes, and have not been put into practical use. Although recent organic electroluminescent devices have been gradually improved, there is a demand for further excellent materials in terms of emission efficiency characteristics, driving voltage characteristics, and long-life characteristics. Furthermore, depending on the application such as in-vehicle use, high heat resistance may be required, and the material is required to have a high glass transition temperature (Tg).

[0003] Examples of electron transport materials excellent in long-life properties for organic electroluminescent devices include adamantane compounds disclosed in Patent Document 1 or 2 and dibenzofuran compounds disclosed in Patent Document 3. However, further improvements have been demanded in terms of the heat resistance of the materials and the lifetime and emission efficiency of the organic electroluminescent devices using such materials.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] One aspect of the present invention is to provide a novel adamantane compound, and another aspect is to provide an organic electroluminescent device excellent in heat resistance and excellent in long-life properties or emission efficiency.

Means for Solving the Problems

[0006] An adamantane compound according to one embodiment of the present invention is as follows. 1. An adamantane compound represented by the general formula (1).

[0007]

Chemical formula

[0008]

Chem.

Advantages of the Invention

[0009] According to one aspect of the present invention, a novel adamantane compound can be provided, and in another aspect, an electron transport material excellent in heat resistance, long life, or luminous efficiency can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail.

[0012] One aspect of the present invention relates to an adamantane compound represented by the above general formula (1) (hereinafter, also referred to as adamantane compound (1)), and an organic electroluminescent device containing the same.

[0013] <Adamantane Compound Represented by General Formula (1)> An adamantane compound which is one of the embodiments of the present invention is represented by general formula (1).

[0014]

Chemical Formula

[0015] The adamantane compound represented by formula (1) according to an embodiment of the present invention has a large steric - hindrance adamantyl group and an aromatic group having at least one Group 16 element and having 4 to 30 carbon atoms. Therefore, it has high amorphousness, a high glass transition temperature compared to its molecular weight, and electroluminescent element characteristics such as high luminous efficiency, long life, and low voltage.

[0016] The Tg of the adamantane compound represented by formula (1) according to an embodiment of the present invention is preferably 110 °C or higher, and more preferably 130 °C or higher. This Tg is measured using a DSC (Differential scanning calorimetry) apparatus under an atmosphere of 23 °C and 50% RH.

[0017] ≪G≫ G represents an aromatic group having 4 to 30 carbon atoms and having at least one Group 16 element. Examples of the Group 16 element include an oxygen atom, a sulfur atom, a selenium atom, etc., but it is preferably an aromatic group having 4 to 30 carbon atoms and having at least one oxygen atom or sulfur atom.

[0018] The aromatic group having 4 to 30 carbon atoms is preferably a furanyl group, a benzofuranyl group, a dibenzofuranyl group, a thiophenyl group, a benzothiophenyl group, a dibenzothiophenyl group.

[0019] ≪Ar 1 、Ar2 and Ar 3 >> Ar 1 and Ar 2 each independently represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms. Ar 3 represents an aromatic hydrocarbon group having 6 to 24 carbon atoms;

[0020] Ar 1 Ar 2 and Ar 3 Examples of the aromatic hydrocarbon group having 6 to 24 carbon atoms in Ar, Ar, and Ar are not particularly limited, but phenyl group, biphenyl group, naphthyl group, phenanthryl group, anthryl group, pyrenyl group, triphenylenyl group, chrysenyl group, fluoranthenyl group, acenaphthylenyl group, fluorenyl group, benzofluorenyl group, etc. are preferable examples.

[0021] Ar 1 Ar 2 Ar 3 and G may be substituted with one or more substituents selected from the group consisting of a single or plural phenyl groups, naphthyl groups, phenanthryl groups, anthryl groups, triphenylenyl groups, pyridyl groups, pyrimidyl groups, pyrazyl groups, triazyls, biphenylyl groups, terphenyl groups, quinolyl groups, isoquinolyl groups, methyl groups, tert-butyl groups, fluoro groups, or deuteriums.

[0022] Ar 2 is preferably an aromatic hydrocarbon group having 6 to 24 carbon atoms, and Ar, Ar, Ar, and G are preferably unsubstituted. 1 Ar 2 Ar 3 and G are preferably unsubstituted.

[0023] Ar 3 is preferably an unsubstituted phenyl group, biphenylyl group, naphthyl group, phenyl group substituted with a naphthyl group, phenanthryl group, anthryl group, phenyl group substituted with an anthryl group.

[0024] <<a, b, c and d>> a represents 1 or 2, b represents 1 or 2, c represents 0 or 1, and d represents 1 or 2, respectively. However, a + b + c = 3. It is preferable that a = b = c = 1.

[0025] ≪Z 1 、Z 2 およびZ 3 ≫ Z 1 、Z 2 およびZ 3 each independently represents a nitrogen atom or C-H. Among Z 1 、Z 2 およびZ 3 it is preferable that at least two of them are nitrogen atoms. It is more preferable that two are nitrogen atoms and one is C-H.

[0026] <Preferred examples of the adamantane compound represented by the general formula (1)> Examples of the adamantane compound represented by the general formula (1) include compounds represented by the following (1a) to (1t).

[0027]

Chemical formula

[0028]

Chemical formula

[0029]

Chemical formula

[0030] The G-Ar 1 - is not particularly limited, and the following (A1) to (A172) are given as examples.

[0031]

Chemical formula

[0032] [Chemistry]

[0033] [Chemistry]

[0034] [Chemistry]

[0035] [Chemistry]

[0036] [Chemistry]

[0037] [Chemistry]

[0038] [Chemistry]

[0039] [Chemistry]

[0040] [Chemistry]

[0041] [Chemistry]

[0042] Said Ad-Ar 2- Although not particularly limited, the following (B1)-(B66) are given as examples. However, Ad in the formula 1 and Ad 2 represent 1-adamantyl group and 2-adamantyl group, respectively.

[0043]

Chemical formula

[0044]

Chemical formula

[0045]

Chemical formula

[0046]

Chemical formula

[0047] Although not particularly limited, the following (C1)-(C117) are given as examples of the Ar 3 -.

[0048]

Chemical formula

[0049]

Chemical formula

[0050]

Chemical formula

[0051]

Chemical formula

[0052]

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[0054]

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[0055] More preferred examples include the following (D1)-(D692).

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[0059]

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[0060]

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[0061]

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[0065]

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Chem.

[0070]

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[0080]

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[0084] [Chemistry]

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[0089] [Chemistry]

[0090] [Chemistry]

[0091] Incidentally, the Tg of all the exemplified compounds is 100°C or higher.

[0092] <Method for producing an adamantane compound represented by formula (1)> The adamantane compound (1) according to an embodiment of the present invention can be produced, for example, by the cross-coupling reactions shown in the following reaction formulas 1 to 6.

[0093] [Chemistry]

[0094] [Chemistry]

[0095] [Chemical formula]

[0096] [Chemical formula]

[0097] [Chemical formula]

[0098] [Chemical formula]

[0099] In Reaction Formulas 1 to 6, X represents F, Cl, Br, I, OTf, or a group having F, Cl, Br, I, or OTf as a partial structure. M represents a metal group or an organometallic group effective for the coupling reaction, and examples thereof include Li, Na, B(OR 1 )2, MgBr, MgCl, ZnCl, ZnBr, ZnCl, Zn(tmeda), Sn(n-Bu)3, SiMe3, etc.

[0100] Here, R 1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and two R 1 may be the same or different. Also, two OR 1 and the boron atom may form a ring. That is, examples of B(OR 1 )2 include the following (I) to (VI).

[0101] [Chemical formula]

[0102] The reaction conditions for the cross-coupling reaction can be produced, for example, using the methods described in JP 2015-34159 and WO 2019 / 191454.

[0103] <Organic electroluminescent device containing an adamantane compound represented by formula (1)> Hereinafter, an organic electroluminescent device containing the adamantane compound (1) (hereinafter sometimes simply referred to as an organic electroluminescent device) will be described. The organic electroluminescent device according to one aspect of the present invention contains the adamantane compound (1). The configuration of the organic electroluminescent device is not particularly limited, and examples thereof include the configurations (i) to (v) shown below.

[0104] (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

[0105] The adamantane compound (1) may be contained in any of the above layers, but is preferably contained in one or more layers selected from the group consisting of the layers between the light-emitting layer and the cathode in terms of excellent light-emitting characteristics of the organic electroluminescent device. Therefore, in the case of the configurations shown in (i) to (v) above, it is preferable that the adamantane compound (1) is contained in one or more layers selected from the group consisting of the electron transport layer and the electron injection layer.

[0106] Hereinafter, the organic electroluminescent device according to one aspect of the present invention will be described in more detail with reference to FIG. 1, taking the configuration of (v) above as an example.

[0107] The organic electroluminescent device shown in FIG. 1 has a so-called bottom emission type device structure, but the organic electroluminescent device according to one aspect of the present invention is not limited to the bottom emission type device structure. That is, the organic electroluminescent device according to one aspect of the present invention may have other known device structures such as a top emission type.

[0108] The organic electroluminescent device 100 includes a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode 8 in this order. However, some of these layers may be omitted, and conversely, other layers may be added. For example, a hole blocking layer may be provided between the light emitting layer 5 and the electron transport layer 6, the hole injection layer 3 may be omitted, and the hole transport layer 4 may be directly provided on the anode 2.

[0109] Further, for example, a single layer having functions of a plurality of layers, such as an electron injection / transport layer having functions of an electron injection layer and an electron transport layer in a single layer, may be provided instead of the plurality of layers. Furthermore, for example, a single-layer hole transport layer 4 and a single-layer electron transport layer 6 may each be composed of a plurality of layers.

[0110] <Layer containing adamantane (1)> In the configuration example shown in FIG. 1, the organic electroluminescent device 100 contains an adamantane compound (1) in at least one layer selected from the group consisting of the light emitting layer 5, the electron transport layer 6, and the electron injection layer 7. In particular, it is preferable that the electron transport layer 6 contains the adamantane compound (1). The adamantane compound (1) may be contained in a plurality of layers provided in the organic electroluminescent device.

[0111] Hereinafter, the organic electroluminescent device 100 in which the electron transport layer 6 contains the adamantane compound (1) will be described.

[0112] [Substrate 1] Examples of the substrate 1 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-transmissive plastic film are preferable.

[0113] Examples of the light-transmissive plastic film 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 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.

[0114] [Anode 2] An anode 2 is provided on the substrate 1 (on the hole injection layer 3 side). Examples of the anode material include metals, alloys, electrically conductive compounds, and mixtures thereof having a large work function (for example, 4 eV or more). Specific examples of the anode material include metals such as Au; and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO. In the case of an organic electroluminescent element having a configuration in which light emission is extracted through the anode, the anode is formed of a conductive transparent material that passes or substantially passes the light emission.

[0115] [Hole injection layer 3, hole transport layer 4] Between the anode 2 and the light emission layer 5 described later, a hole injection layer 3 and a hole transport layer 4 are provided in this order from the anode 2 side.

[0116] The hole injection layer and the hole transport layer have a function of transmitting holes injected from the anode to the light emission layer. By interposing the hole injection layer and the hole transport layer between the anode and the light emission layer, more holes are injected into the light emission layer at a lower electric field.

[0117] In addition, 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 suppressed from leaking into the hole injection layer and / or the hole transport layer by the electron barrier existing 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, bringing about effects such as improved light-emitting efficiency, and an organic electroluminescent device with excellent light-emitting performance can be obtained.

[0118] As materials for the hole injection layer and the hole transport layer, those having at least any one of hole injection property, hole transport property, and electron barrier property are used. The materials for the hole injection layer and the hole transport layer may be either organic substances or inorganic substances.

[0119] Specific examples of the materials for the hole injection layer and the 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 (especially thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds, styrylamine compounds, and the like.

[0120] Among these, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferable in terms of the good performance of the organic electroluminescent device, and aromatic tertiary amine compounds are particularly preferable.

[0121] Specific examples of the aromatic tertiary amine compound and the styrylamine compound 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’-di(4-methoxyphenyl)-4,4’-diaminobiphenyl, N,N,N’,N’-tetraphenyl-4,4’-diaminodiphenyl ether, 4,4’-bis(diphenylamino)quarterphenyl, 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-(m-tolyl)-N-phenylamino]triphenylamine (MTDATA), and the like.

[0122] In addition, inorganic compounds such as p-type Si and p-type SiC can also be cited as an example of the material for the hole injection layer and the hole transport layer. The hole injection layer and the hole transport layer may have a single structure composed of one or more materials, or may have a laminated structure composed of a plurality of layers of the same composition or different compositions.

[0123] [Light-emitting layer 5] A light-emitting layer 5 is provided between the hole transport layer 4 and the electron transport layer 6 described later. Examples of the material 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.

[0124] The light-emitting layer may be composed of a single low-molecular material or a single polymer material, but more commonly, it is composed of a host material doped with a guest compound. The light emission mainly occurs from the dopant and can have any color.

[0125] Examples of the host material include compounds having a biphenylyl group, a fluorenyl group, a triphenylsilyl group, a carbazole group, a pyrenyl group, and an anthryl group. More specifically, DPVBi (4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl), BCzVBi (4,4'-bis(9-ethyl-3-carbazolvinylene)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, etc.

[0126] Examples of the fluorescent dopant include anthracene, pyrene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, quinacridone, dicyanomethylene pyran compounds, thiopyran compounds, polymethine compounds, pyrylium, thiapyrylium compounds, fluorene derivatives, periflanthene derivatives, indenoperylene derivatives, bis(azinyl)amine boron compounds, bis(azinyl)methane compounds, carbostyryl compounds, boron compounds, cyclic amine compounds, etc. The fluorescent dopant may be a combination of two or more selected from these.

[0127] Examples of the phosphorescent dopant include organometallic complexes of transition metals such as iridium, platinum, palladium, osmium, and the like.

[0128] Specific examples of the fluorescent dopant and the phosphorescent dopant 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))), and the like.

[0129] Further, 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 (the hole transport layer 4 or the electron transport layer 6). Thereby, the light-emitting efficiency of the organic electroluminescent element can be further increased.

[0130] The light-emitting layer may have a single-layer structure composed of one or more materials, or may have a laminated structure composed of a plurality of layers of the same composition 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 described later. The electron transport layer has a function of transmitting 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.

[0131] The electron transport layer preferably contains the adamantane compound (1). Further, the electron transport layer may contain one or more selected from conventionally known electron transport materials in addition to the adamantane compound (1).

[0132] In addition, when the adamantane compound (1) is not included in the electron transport layer but is included in other layers, one or more selected from conventionally known electron transport materials can be used as the electron transport material constituting the electron transport layer.

[0133] Examples of conventionally known electron transporting materials include alkali metal complexes, alkaline earth metal complexes, and rare earth metal complexes. Examples of alkali metal complexes, alkaline earth metal complexes, and rare earth metal complexes include lithium 8-hydroxyquinolinate (Liq), zinc bis(8-hydroxyquinolinate), copper bis(8-hydroxyquinolinate), manganese bis(8-hydroxyquinolinate), aluminum tris(8-hydroxyquinolinate), aluminum tris(2-methyl-8-hydroxyquinolinate), gallium tris(8-hydroxyquinolinate), beryllium bis(10-hydroxybenzo[h]quinolinate), zinc bis(10-hydroxybenzo[h]quinolinate), gallium bis(2-methyl-8-quinolinato)chloride, gallium bis(2-methyl-8-quinolinato)(o-cresolato), aluminum bis(2-methyl-8-quinolinato)-1-naphtholate, gallium bis(2-methyl-8-quinolinato)-2-naphtholate, and the like.

[0134] The electron transport layer may have a single-layer structure composed of one or more materials, or may have a laminated structure composed of a plurality of layers of the same composition or different compositions.

[0135] In the organic electroluminescent element according to this embodiment, an electron injection layer may be provided for the purpose of improving electron injection properties and improving element characteristics (for example, luminous efficiency, low-voltage driving, or high durability).

[0136] [Electron injection layer 7] An electron injection layer 7 is provided between the electron transport layer 6 and the cathode 8 described later. The electron injection layer has a function of transmitting electrons injected from the cathode to the light-emitting layer. By interposing the electron injection layer between the cathode and the light-emitting layer, electrons are injected into the light-emitting layer at a lower electric field.

[0137] Examples of materials for the electron injection layer include organic compounds such as fluorenone, anthraquinodimethane, diphenoquinone, thiopyrandioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane, and anthrone. In addition, examples of materials for the electron injection layer also 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.

[0138] [Cathode 8] A cathode 8 is provided on the electron injection layer 7. In the case of an organic electroluminescent element configured to extract only the light emitted through the anode, the cathode can be formed from any conductive material.

[0139] Examples of materials for the cathode include, for example, metals with a small work function (hereinafter also referred to as electron-injecting metals), alloys, electrically conductive compounds, and mixtures thereof. Here, the metal with a small work function is, for example, a metal with 4 eV or less.

[0140] Specific examples of materials for the cathode include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture, indium, lithium / aluminum mixture, rare earth metals, and the like.

[0141] Among these, from the viewpoints of electron injection properties and durability against oxidation and the like, mixtures of an electron-injecting metal and a second metal that is a metal with a larger and more stable work function value than this, such as a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al2O3) mixture, a lithium / aluminum mixture, and the like are preferable.

[0142] [Method for forming each layer] Each layer except the electrodes (anode, cathode) described above can be formed by thinning into a thin film by a known method such as a vacuum evaporation method, a spin coating method, a casting method, or an LB (Langmuir - Blodgett method). The material of each layer may be used alone, or may be used together with a material such as a binder resin and a solvent as needed.

[0143] There is no particular limitation on the film thickness of each layer formed in this way, and it can be appropriately selected according to the situation. Usually, it is in the range of 5 nm to 5 μm.

[0144] The anode and cathode can be formed by thinning the electrode material into a thin film by a method such as evaporation or sputtering. A pattern may be formed through a mask of a desired shape during evaporation or sputtering, or after forming a thin film by evaporation, sputtering, etc., a pattern of a desired shape may be formed by photolithography.

[0145] 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.

[0146] In addition, when forming a layer containing the adamantane compound (1), it may be used in combination with the above - mentioned conventionally known electron - transporting material. Therefore, for example, the adamantane compound (1) and a conventionally known electron - transporting material may be co - evaporated, or a layer of a conventionally known electron - transporting material may be laminated on the layer of the adamantane compound (1).

[0147] The organic electroluminescent element may be used as a kind of lamp such as for illumination or an exposure light source, or may be used as a projection device of a type that projects an image onto a screen or the like, or a display device (display) of a type that directly visualizes a still image or a moving image. When using an organic electroluminescent element as a display device for video playback, as a driving method, a simple matrix (passive matrix) method or an active matrix method may be used. Further, by using two or more organic electroluminescent elements having different emission colors, a full-color display device can be manufactured.

[0148] The adamantane compound (1) can provide an organic electroluminescent element that is significantly superior in luminous efficiency and low-voltage characteristics compared to conventionally known adamantane compounds when used as an electron transport layer. Further, the adamantane compound (1) has high amorphicity due to its steric hindrance skeleton and has high film quality stability. For this reason, effects such as improvement of the driving stability of the organic electroluminescent element and improvement of the luminous efficiency are expected. In addition, the adamantane compound (1) has high chemical stability due to its characteristic skeleton and can contribute to extending the life of the organic electroluminescent element.

[0149] The adamantane compound (1) can provide a triazine compound that can achieve high-dimensional low-voltage driving, high efficiency, and long life of the element by being used as an electron transport layer of an organic electroluminescent element. Further, an organic electroluminescent element that can exhibit low-voltage driving, high efficiency, and long life using the adamantane compound (1) can be provided.

Examples

[0150] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to examples and reference examples, but the present invention is not construed as being limited thereto.

[0151] 1 1H-NMR measurement] 1 For the measurement of 1H-NMR, Bruker ASCEND HD (400 MHz; manufactured by BRUKER) was used.​1 1H-NMR was measured using deuterated chloroform (CDCl3) as the measurement solvent and tetramethylsilane (TMS) as the internal standard substance. Commercially available products were used for the reagents. [FDMS Measurement] FDMS measurement was performed using an M-80B manufactured by Hitachi, Ltd.

[0152] [DSC Measurement (Glass Transition Temperature, Crystallization Temperature)] The glass transition temperature (Tg) and crystallization temperature (Tc) were measured using a DSC (Differential scanning calorimetry) apparatus DSC7020 (manufactured by Hitachi High-Tech Science Corporation). Aluminum oxide (Al2O3) was used as the reference in the DSC measurement, and the measurement was performed with a 10 mg sample. As a pretreatment for the measurement, the temperature was raised from 30 °C to a temperature above the melting point at a rate of 10 °C / min to melt the sample, and then the sample was quenched by contacting it with dry ice. Subsequently, the pretreated sample was heated at a rate of 10 °C / min from 30 °C, and the glass transition temperature and crystallization temperature were measured.

[0153] [Synthesis Example] [[Synthesis Example - 1]]

[0154] [Chemical Structure]

[0155] Under an argon atmosphere, 4-(1-adamantyl)phenyl triflate (150.0 g, 416.2 mmol), bis(neopentyl glycolato)diboron (103.4 g, 457.8 mmol), potassium acetate (122.5 g, 1248.6 mmol), and palladium acetate (1.87 g, 8.32 mmol) were suspended in THF (1340 mL) and heated to reflux for 17 hours. After the resulting reaction mixture was cooled to room temperature, the reaction residue was removed by filtration. The obtained filtrate was concentrated to dryness and purified by silica gel chromatography (developing solvent: toluene) to obtain the target 5,5-dimethyl-2-[4-(1-adamantyl)phenyl]-1,3,2-dioxaborolane (85.0 g, yield 63%). 1 HNMR(CDCl3)δ1.01(s,6H),1.56(s,4H),1.77(brs,6H),1.92(brs,6H),2.09(brs,3H),7.36(d,J=8.4Hz,2H),7.75(d,J=8.4Hz,2H).

[0156] ≪Synthesis Example - 2 (D10)≫

[0157]

Chemical Structure

[0158] Under an argon atmosphere, 2-(4-biphenylyl)-4-chloro-6-(dibenzofuran-2-yl)-1,3,5-triazine (4.00 g, 9.22 mmol), 5,5-dimethyl-2-[4-(1-adamantyl)phenyl]-1,3,2-dioxaborinane (3.29 g, 10.1 mmol), and tetrakis(triphenylphosphine)palladium (213 mg, 0.184 mmol) were suspended in THF (184 mL). To this suspension, an aqueous solution of 2.0 M potassium phosphate (13.8 mL) was added, and the mixture was then heated under reflux for 12 hours. After cooling to room temperature, water and methanol were added to the reaction mixture. The resulting solid was collected by filtration and purified by recrystallization from toluene to obtain the desired 2-[4-(1-adamantyl)phenyl]-4-(4-biphenylyl)-6-(dibenzofuran-2-yl)-1,3,5-triazine (Compound D10) (5.05 g, 90% yield). 1 HNMR(CDCl3)δ1.83(brs,6H),2.03(brs,6H),2.17(brs,3H),7.41-7.46(m,2H),7.50-7.55(m,3H),7.61(d,J=8.7Hz,2H),7.64(d,J=8.3Hz,1H),7.72-7.76(m,3H),7.84(d,J=8.7Hz,2H),8.18(brd,J=7.6Hz,1H),8.76(d,J=8.4Hz,2H),8.88(d,J=8.4Hz,2H),8.98(dd,J=8.7,1.8Hz,1H),9.41(d,J=1.4Hz,1H). The Tg of Compound D10 was 140 °C, and no Tc was detected.

[0159] ≪Synthesis Example - 3 (D12)≫

[0160]

Chemical Structure

[0161] 2-(4-Biphenylyl)-4-chloro-6-(dibenzofuran-4-yl)-1,3,5-triazine and 5,5-dimethyl-2-[4-(1-adamantyl)phenyl]-1,3,2-dioxaborinane were reacted in the same manner as in Synthesis Example-2 to obtain the target 2-[4-(1-adamantyl)phenyl]-4-(4-biphenylyl)-6-(dibenzofuran-2-yl)-1,3,5-triazine (Compound D12). FDMS: 609

[0162] ≪Synthesis Example-4≫

[0163]

Chemical Structure

[0164] Under an argon atmosphere, 2,4-dichloro-6-phenyl-1,3,5-triazine (10.0 g, 33.1 mmol), 4-chlorophenylboronic acid (5.69 g, 36.4 mmol), and tetrakis(triphenylphosphine)palladium (765 mg, 0.662 mmol) were suspended in THF (330 mL). To this suspension, 2.0 M aqueous potassium carbonate solution (49.6 mL) was added, and then the mixture was heated to reflux for 12 hours. After cooling, water and methanol were added to the reaction mixture. The resulting solid was collected by filtration and purified by recrystallization from toluene to obtain the target 2-(4-biphenylyl)-4-chloro-6-(4-chlorophenyl)1,3,5-triazine (12.5 g, yield 40%). 1 HNMR(CDCl3) δ 7.43 (t, J = 7.3 Hz, 1H), 7.49 (d, J = 7.8 Hz, 2H), 7.54 (d, J = 8.7 Hz, 2H), 7.69 (dd, J = 8.5, 1.5 Hz, 2H), 7.79 (d, J = 8.6 Hz, 2H), 8.60 (d, J = 8.7 Hz, 2H), 8.69 (d, J = 8.5 Hz, 2H).

[0165] ≪Synthesis Example-5≫

[0166]

Chemical Structure

[0167] Under an argon atmosphere, 2-(4-biphenylyl)-4-chloro-6-(4-chlorophenyl)-1,3,5-triazine (5.00 g, 13.2 mmol), 5,5-dimethyl-2-[4-(1-adamantyl)phenyl]-1,3,2-dioxaborinane (4.29 g, 13.2 mmol), and tetrakis(triphenylphosphine)palladium (306 mg, 0.264 mmol) were suspended in toluene (132 mL). To this suspension, 2.0 M aqueous potassium phosphate solution (19.8 mL) was added, and then the mixture was heated to reflux for 21 hours. After cooling to room temperature, water and methanol were added to the reaction mixture. The resulting solid was collected by filtration and purified by recrystallization from toluene to obtain the desired 2-(4-adamantylphenyl)-4-(4-biphenylyl)-6-(4-chlorophenyl)-1,3,5-triazine (6.2 g, 85% yield). 1 HNMR(CDCl3)δ1.82(brs,6H),2.01(brs,6H),2.15(brs,3H),7.42(t,J=7.2Hz,1H),7.49-7.53(m,2H),7.55(d,J=8.9Hz,2H),7.58(d,J=8.6Hz,2H),7.71(dd,J=8.3,1.2Hz,2H),7.81(d,J=8.6Hz,2H).

[0168] <<Synthesis Example - 6>>

[0169]

Chemical Structure

[0170] Under an argon atmosphere, 2-(4-adamantylphenyl)-4-(4-biphenylyl)-6-(4-chlorophenyl)-1,3,5-triazine (5.00 g, 9.02 mmol), bis(pinacolato)diboron (2.75 g, 10.8 mmol), palladium acetate (40.5 mg, 0.18 mmol), 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (172 mg, 0.361 mmol), and potassium acetate (2.66 g, 27.1 mmol) were suspended in THF (90 mL) and heated to reflux for 17 hours. After the resulting reaction mixture was cooled to room temperature, the reaction residue was removed by filtration. The obtained filtrate was concentrated to dryness and purified by silica gel chromatography (developing solvent: a mixed solvent of toluene and hexane) to obtain the target 2-(4-adamantylphenyl)-4-(4-biphenylyl)-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3,5-triazine (4.19 g, yield 72%). 1 HNMR(CDCl3)δ1.40(s,12H),1.82(brs,6H),2.01(brs,6H),2.12(brs,3H),7.42(t,J=7.5Hz,1H),7.51(t,J=7.5Hz,2H),7.59(d,J=8.7Hz,2H),7.72(dd,J=8.5,1.4Hz,2H),7.82(d,J=8.3Hz,2H),8.01(d,J=8.3Hz,2H),8.72(d,J=8.5Hz,2H),8.77(d,J=8.1Hz,2H),8.85(d,J=8.4Hz,2H).

[0171] ≪Synthesis Example - 7 (D14)≫

[0172]

Chemical Structure

[0173] Under an argon atmosphere, 2-(4-adamantylphenyl)-4-(4-biphenylyl)-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3,5-triazine (2.00 g, 3.10 mmol), 2-bromodibenzofuran (919 mg, 3.72 mmol), palladium acetate (13.9 mg, 0.062 mmol), and 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (59.1 mg, 0.124 mmol) were suspended in THF (31 mL). To this suspension, 2.0 M aqueous potassium phosphate solution (4.7 mL) was added, and then the mixture was heated under reflux for 20 hours. After cooling to room temperature, water and methanol were added to the reaction mixture. The resulting solid was collected by filtration and purified by recrystallization from a mixed solvent of toluene and 1-butanol to obtain the desired 2-[4-(1-adamantyl)phenyl]-4-(4-biphenylyl)-6-[4-(dibenzofuran-4-yl)phenyl]-1,3,5-triazine (Compound D14) (1.69 g, 80% yield). 1 HNMR(CDCl3)δ1.83(brs,6H),2.02(brs,6H),2.16(brs,3H),7.38-7.44(m,2H),7.49-7.54(m,3H),7.59-7.63(m,3H),7.69(d,J=8.6H,1H),7.73(brd,J=7.3Hz,2H),7.82(dd,J=8.6,1.8Hz,1H),7.83(d,J=8.4Hz,2H),7.90(d,J=8.3Hz,2H),8.07(brd,J=7.3Hz,1H),8.28(brs,1H),8.75(d,J=8.4Hz,2H),8.88(d,J=8.4Hz,2H),8.90(d,J=8.3Hz,2H). The Tg of the obtained Compound D14 was 153 °C, and Tc was not detected.

[0174] ≪Synthesis Example - 8 (D16)≫

[0175]

Chemical Structure

[0176] ≪Synthesis Example-9 (D666)≫

[0177]

Chemical Structure

[0178] 2-(4-Adamantylphenyl)-4-(4-biphenylyl)-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3,5-triazine and 4-bromodibenzothiophene were reacted in the same manner as in Synthesis Example-7 to obtain the desired 2-[4-(1-adamantyl)phenyl]-4-(4-biphenylyl)-6-[4-(dibenzothiophene-4-yl)phenyl]-1,3,5-triazine (Compound D666). FDMS: 701

[0179] ≪Comparative Example-1≫ ETL1 was synthesized by the method described in Example 5 of JP 2015-134743 A. The Tg of the obtained compound was 103 °C and the Tc was 160 °C.

[0180]

Chemical Structure

[0181] ≪Comparative Example-2≫ ETL2 was synthesized by the method described in Example 8 of JP 2015-34159 A. The Tg of the obtained compound was 102 °C and the Tc was 176 °C.

[0182] [Chemical formula]

[0183] <<Comparative Example - 3>> ETL3 was synthesized by the method described in Example 22 of Japanese Patent Application Laid - Open No. 2007 - 314503. The Tg of the obtained compound was 124°C and the Tc was 174°C.

[0184] [Chemical formula]

[0185] From the above results, it was confirmed that the compounds D10 and D14 obtained in this example have a higher Tg than the conventionally known electron - transporting materials ETL1 and ETL2. Furthermore, since no crystallization peak was detected, it is expected to form a film structure with high amorphousness during vapor deposition film formation. It is presumed that this has led to the realization of high efficiency and long life of the organic electroluminescent device, which is one embodiment of the present invention.

[0186] [Organic electroluminescent device example] The materials used are as follows. The materials used were sublimation - purified before use.

[0187] [Chemical formula]

[0188] [Device Example - 1 (see Figure 2)] [Preparation of substrate 1 and anode 2] As the substrate 1 provided with the anode 2 on its surface, a glass substrate with an indium tin oxide (ITO) transparent electrode, on which a 2 - mm - wide ITO film (film thickness 110 nm) was patterned in a stripe shape, was prepared. Then, this substrate was washed with isopropyl alcohol and then surface - treated by ozone ultraviolet cleaning.

[0189] [Preparation for vacuum evaporation] On the substrate with surface treatment after washing, vacuum evaporation of each layer was performed by the vacuum evaporation method to form each layer by lamination. First, the glass substrate was introduced into the vacuum evaporation chamber and the pressure was reduced to 1.0×10 -4 Pa. Then, they were respectively fabricated according to the film formation conditions of each layer in the following order. Each organic material was formed by a resistance heating method.

[0190] (Fabrication of the hole injection layer 3) N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine and 1,2,3-tris[(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane were formed into a film with a thickness of 10 nm at a ratio of 99:1 (mass ratio) to fabricate the hole injection 3. The film formation rate was 0.1 nm / second.

[0191] (Fabrication of the first hole transport layer 41) N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine was formed into a film with a thickness of 85 nm at a rate of 0.2 nm / second to fabricate the first hole transport layer 41.

[0192] (Fabrication of the second hole transport layer 42) N-phenyl-N-(9,9-diphenylfluorene-2-yl)-N-(1,1'-biphenyl-4-yl)amine was formed into a film with a thickness of 5 nm at a rate of 0.15 nm / second to fabricate the second hole transport layer 42.

[0193] (Fabrication of the light-emitting layer 5) 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tert-butylphenyl)]amino-bisbenzofurano-9,9'-spirofluorene were formed into a film with a thickness of 20 nm at a ratio of 95:5 (mass ratio) to fabricate the light-emitting layer 5. The film formation rate was 0.1 nm / second.

[0194] (Fabrication of the hole blocking layer 9) 2-[3’-(9,9-Dimethyl-9H-fluoren-2-yl)[1,1’-biphenyl]-3-yl]-4,6-diphenyl-1,3,5-triazine was formed into a film with a thickness of 6 nm at a rate of 0.05 nm / second to fabricate a hole-blocking layer 9.

[0195] (Fabrication of the electron transport layer 6) 2-[4-(1-Adamantyl)phenyl]-4-(4-biphenylyl)-6-(dibenzofuran-2-yl)-1,3,5-triazine (Compound D10) synthesized in Synthesis Example-2 and lithium 8-hydroxyquinolinate (hereinafter, Liq) were formed into a film with a thickness of 25 nm at a ratio of 50:50 (mass ratio) to fabricate an electron transport layer 6. The film-forming rate was 0.15 nm / second.

[0196] (Fabrication of the electron injection layer 7) Liq was formed into a film with a thickness of 1 nm at a rate of 0.02 nm / second to fabricate an electron injection layer 7.

[0197] (Fabrication of the cathode 8) Finally, a metal mask was arranged so as to be orthogonal to the ITO stripe (anode 2) on the substrate 1, and the cathode 8 was formed into a film. The cathode was formed into a film with a thickness of 80 nm and 20 nm, respectively, in this order, of silver / magnesium (mass ratio 1 / 10) and silver to form a two-layer structure. The film-forming rate of silver / magnesium was 0.5 nm / second, and the film-forming rate of silver was 0.2 nm / second.

[0198] As described above, an organic electroluminescent element 100 having a light-emitting area of 4 mm2 as shown in FIG. 2 was fabricated. The respective film thicknesses were measured with a stylus type film thickness gauge (DEKTAK, manufactured by Bruker).

[0199] Furthermore, this element was sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less. The sealing was performed using a glass sealing cap and a film-forming substrate (element) and a bisphenol F type epoxy resin (manufactured by Nagase ChemteX).

[0200] <Element Example-2> In Device Example-1, instead of forming a 25-nm film (film formation rate: 0.15 nm / second) of 2-[4-(1-adamantyl)phenyl]-4-(4-biphenylyl)-6-(dibenzofuran-2-yl)-1,3,5-triazine (Compound D10) and Liq on the electron transport layer 6 at a ratio of 50:50 (mass ratio), a 25-nm film (film formation rate: 0.15 nm / second) of 2-[4-(1-adamantyl)phenyl]-4-(4-biphenylyl)-6-[4-(dibenzofuran-4-yl)phenyl]-1,3,5-triazine (Compound D14) and Liq synthesized in Synthesis Example-7 at a ratio of 50:50 (mass ratio) was formed. An organic electroluminescent device was fabricated in the same manner as in Device Example-1, except for the above.

[0201] <Device Comparative Example-1> In Device Example-1, instead of forming a 25-nm film (film formation rate: 0.15 nm / second) of 2-[4-(1-adamantyl)phenyl]-4-(4-biphenylyl)-6-(dibenzofuran-2-yl)-1,3,5-triazine (Compound D10) and Liq on the electron transport layer 6 at a ratio of 50:50 (mass ratio), a 25-nm film (film formation rate: 0.15 nm / second) of ETL-3 synthesized in Comparative Example-3 and Liq at a ratio of 50:50 (mass ratio) was formed. An organic electroluminescent device was fabricated in the same manner as in Device Example-1, except for the above.

[0202] <Evaluation> A direct current was applied to the fabricated organic electroluminescent device, and the luminescence characteristics were evaluated according to the method described in the above luminescence characteristics measurement.

[0203] As the luminescence characteristics, the voltage (V) and power efficiency (lm / A) when a current density of 10 mA / cm2 was passed were measured, and the device lifetime during continuous lighting was measured. The device lifetime was the luminance decay time during continuous lighting when driven at an initial luminance of 1000 cd / m 2 and the time required for the luminance (cd / m 2 ) to decrease by 5% was measured. The values of voltage (V), power efficiency (lm / A), and lifetime were expressed as relative values when Device Comparative Example-1 was set to 100. The results are shown in Table 1. The measurement was carried out in an atmosphere of 23°C and 50% RH. A smaller voltage value indicates better performance, while larger values for efficiency and lifespan indicate better performance respectively.

[0204] [Table 1]

[0205] From Table 1, it can be seen that compared with the device comparative example, the organic electroluminescent device using the adamantane compound (1) according to the embodiment of the present invention has improved characteristics in terms of voltage, current efficiency, and device lifespan. [Industrial Applicability]

[0206] It can be understood that the adamantane compound (1) according to the embodiment of the present invention is a novel adamantane compound with high amorphousness and excellent heat resistance. Therefore, due to its good thermal stability during sublimation purification, it has excellent operability in sublimation purification and can provide a material with few impurities.

[0207] Also, the adamantane compound (1) according to another embodiment of the present invention is used as an electron transport material for an organic electroluminescent device with excellent low driving voltage. Furthermore, according to the present invention, an organic electroluminescent device with excellent power consumption can be provided.

[0208] Furthermore, the adamantane compound (1) according to another embodiment of the present invention can provide a long lifespan organic electroluminescent device because of its excellent stability of the vapor deposition film.

[0209] And the thin film composed of the adamantane compound (1) according to another embodiment of the present invention is excellent in electron transport ability, hole blocking ability, redox resistance, water resistance, oxygen resistance, electron injection characteristics, etc., so it is useful as a material for organic electroluminescent devices, especially useful as an electron transport material, hole blocking material, light emitting host material, etc. Also, since the adamantane compound (1) according to the embodiment of the present invention is a wide bandgap compound, it can be suitably used not only for fluorescent device applications but also for phosphorescent devices. [Explanation of Reference Signs]

[0210] 1. Glass substrate 2. Anode 3. Hole injection layer 4. Hole transport layer 41. First hole transport layer 42. Second hole transport layer 5. Light emitting layer 9. Hole blocking layer 6. Electron transport layer 7. Electron injection layer 8. Cathode

Claims

1. An adamantane compound represented by the general formula (1). 【Chemical 1】 In the formula, G represents a furanyl group, a benzofuranyl group, a thiophenyl group, or a benzothiophenyl group; Ar １ represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar ２ represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar ３ represents an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar １ 、Ar ２ 、Ar ３ and G may be substituted with one or more substituents selected from the group consisting of phenyl, naphthyl, phenanthryl, anthryl, triphenylenyl, pyridyl, pyrimidyl, pyrazyl, triazine, biphenylyl, terphenyl, quinolyl, isoquinolyl, methyl, tert-butyl, fluoro, or deuterium; Ad represents a 1-adamantyl group or a 2-adamantyl group; a represents 1 or 2; b represents 1 or 2; c represents 0 or 1; d represents 1 or 2; provided that a + b + c = 3; Z １ , Z ２ and Z ３ each independently represents a nitrogen atom or C-H.

2. An adamantane compound represented by the general formula (1). 【Chemical 2】 In the formula, G represents an aromatic group having at least one Group 16 element and having 4 to 30 carbon atoms; Ar1 represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar2 represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar3 represents a naphthyl group, a phenyl group substituted with a naphthyl group, a phenanthryl group, an anthryl group, or a phenyl group substituted with an anthryl group; Ar1, Ar2, Ar3, and G may be substituted with one or more substituents selected from the group consisting of a phenyl group, a naphthyl group, a phenanthryl group, an anthryl group, a triphenylenyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, a biphenylyl group, a terphenyl group, a quinolyl group, an isoquinolyl group, a methyl group, a tert-butyl group, a fluoro group, or deuterium; Ad represents a 1-adamantyl group or a 2-adamantyl group; a represents 1 or 2; b represents 1 or 2; c represents 0 or 1; d represents 1 or 2; provided that a + b + c = 3; Z1, Z2, and Z3 each independently represent a nitrogen atom or C—H.

3. An adamantane compound represented by the general formula (1). [Chemical Formula 3] In the formula, G represents an aromatic group having at least one Group 16 element and having 4 to 30 carbon atoms; Ar1 represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar2 represents an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar3 represents an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar1, Ar2, Ar3, and G may be substituted with one or more substituents selected from the group consisting of a phenyl group, a naphthyl group, a phenanthryl group, an anthryl group, a triphenylenyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, a biphenylyl group, a terphenyl group, a quinolyl group, an isoquinolyl group, a methyl group, a tert-butyl group, a fluoro group, or deuterium; Ad represents a 1-adamantyl group or a 2-adamantyl group; a represents 1 or 2; b represents 1 or 2; c represents 0 or 1; d represents 1 or 2; provided that a + b + c = 3; Z1, Z2 and Z3 each independently represent a nitrogen atom or C—H.

4. The above-mentioned Ar ２ The adamantane compound according to claim 1 or 2, wherein is an aromatic hydrocarbon group having 6 to 24 carbon atoms.

5. The adamantane compound according to claim 2 or 3, wherein G is an aromatic group having 4 to 30 carbon atoms and having at least one oxygen atom or sulfur atom.

6. The adamantane compound according to claim 2, 3, or 5, wherein G is a furanyl group, a benzofuranyl group, a dibenzofuranyl group, a thiophenyl group, a benzothiophenyl group, or a dibenzothiophenyl group.

7. Said Ar ３ is an unsubstituted phenyl group, a biphenylyl group, a naphthyl group, a phenyl group substituted with a naphthyl group, a phenanthryl group, an anthryl group, or a phenyl group substituted with an anthryl group, the adamantane compound according to claim 1 or 3.

8. Said Z １ , Z ２ and Z ３ The adamantane compound according to any one of claims 1 to 7, wherein two or more of them are nitrogen atoms.

9. Said Z １ , Z ２ and Z ３ Among them, two are nitrogen atoms and one is C-H. The adamantane compound according to any one of claims 1 to 8.

10. Said Ar １ , Ar ２ , Ar ３ and G are unsubstituted, the adamantane compound according to any one of claims 1 to 9.

11. The adamantane compound according to any one of claims 1 to 10, wherein c is 1.

12. An organic electroluminescent device containing an adamantane compound represented by the general formula (1). 【Chemical Formula 4】 (In the formula, G represents a furanyl group, a benzofuranyl group, a thiophenyl group, or a benzothiophenyl group; Ar １ represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar ２ represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar ３ represents an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar １ 、Ar ２ 、Ar ３ and G may be substituted with one or more substituents selected from the group consisting of phenyl, naphthyl, phenanthryl, anthryl, triphenylenyl, pyridyl, pyrimidyl, pyrazyl, triazinyl, biphenylyl, terphenyl, quinolyl, isoquinolyl, methyl, tert-butyl, fluoro, or deuterium; Ad represents a 1-adamantyl group or a 2-adamantyl group; a represents 1 or 2; b represents 1 or 2; c represents 0 or 1; d represents 1 or 2; provided that a + b + c = 3; Z １ , Z ２ and Z ３ each independently represents a nitrogen atom or C-H.)

13. An organic electroluminescent device containing an adamantane compound represented by the general formula (1). 【Chemical Formula 5】 (In the formula, G represents an aromatic group having 4 to 30 carbon atoms and having at least one Group 16 element; Ar1 represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar2 represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar3 represents a naphthyl group, a phenyl group substituted with a naphthyl group, a phenanthryl group, an anthryl group, or a phenyl group substituted with an anthryl group; Ar1, Ar2, Ar3 and G may be substituted with one or more substituents selected from the group consisting of a phenyl group, a naphthyl group, a phenanthryl group, an anthryl group, a triphenylenyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazyl, a biphenylyl group, a terphenyl group, a quinolyl group, an isoquinolyl group, a methyl group, a tert-butyl group, a fluoro group, or deuterium; Ad represents a 1-adamantyl group or a 2-adamantyl group; a represents 1 or 2; b represents 1 or 2; c represents 0 or 1; d represents 1 or 2; provided that a + b + c = 3; Z1, Z2 and Z3 each independently represent a nitrogen atom or C—H.)

14. An organic electroluminescent device containing an adamantane compound represented by the general formula (1). 【Chemical Formula 6】 (In the formula, G represents an aromatic group having at least one Group 16 element and having 4 to 30 carbon atoms; Ar1 represents a single bond or an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar2 represents an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar3 represents an aromatic hydrocarbon group having 6 to 24 carbon atoms; Ar1, Ar2, Ar3 and G may be substituted with one or more substituents selected from the group consisting of a phenyl group, a naphthyl group, a phenanthryl group, an anthryl group, a triphenylenyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazyl, a biphenylyl group, a terphenyl group, a quinolyl group, an isoquinolyl group, a methyl group, a tert-butyl group, a fluoro group, or a deuterium; Ad represents a 1-adamantyl group or a 2-adamantyl group; a represents 1 or 2; b represents 1 or 2; c represents 0 or 1; d represents 1 or 2; provided that a + b + c = 3; Z1, Z2 and Z3 each independently represent a nitrogen atom or C—H.)

15. The organic electroluminescent device according to any one of Claims 12 to 14, wherein the layer containing the adamantane compound represented by the general formula (1) is an electron transport layer.

16. The organic electroluminescent device according to any one of Claims 12 to 15, wherein the adamantane compound represented by the general formula (1) is doped.

17. The organic electroluminescent device according to Claim 16, wherein the doping is Liq.

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