TW202304940A - Boron-containing compound, light-emitting material and light-emitting element using same - Google Patents

Abstract

Provided are: a compound represented by formula (II); a luminescent material containing this compound; and a luminescent element containing this luminescent material. (In formula (II), R1, R2, R3, R4, R5, R6, R7 and R8 are each independently a straight chain or branched chain alkyl group having 1-4 carbon atoms, m values are each independently an integer between 0 and 5, and n values are each independently an integer between 0 and 4.).

Description

Boron-containing compound, luminescent material, and light-emitting element using the luminescent material

The invention relates to a boron-containing compound, a luminescent material and a luminescent element using the luminescent material. More specifically, the present invention relates to a boron-containing compound having excellent light-emitting properties, a light-emitting material, and a light-emitting device using the light-emitting material. This application claims priority based on Japanese Patent Application No. 2021-118345 for which it applied in Japan on July 16, 2021, and uses the content for this application.

As a boron-containing compound having luminescence, for example, Patent Document 1 proposes the following boron-containing compound.

[chemical 1]

[Chem 2]

Patent Document 2 proposes a boron-containing compound as follows.

[現有技術文獻] [專利文獻] [Chem 3]

[Prior Art Documents] [Patent Documents]

[Patent Document 1] WO2020/040298A [Patent Document 2] WO2018/212169A

[Problem to be Solved by the Invention] An object of the present invention is to provide a novel boron-containing compound excellent in light-emitting properties, a light-emitting material, and a light-emitting device using the light-emitting material. [Means to solve the problem]

As a result of earnest research to solve the above-mentioned problems, the present invention including the following aspects has been completed.

〔式（I）中， X為N-R、O或S， R為氫原子或碳數1～4的直鏈狀或者分支鏈狀的烷基， R ¹、R ²、R ³、R ⁴、R ⁵、R ⁶、R ⁷及R ⁸分別獨立地為碳數1～4的直鏈狀或者分支鏈狀的烷基， m分別獨立地為0～5的任意整數，並且 n分別獨立地為0～4的任意整數。〕 That is, regarding the present invention, [1] A light-emitting material comprising a compound represented by formula (I). [chemical 4]

[In formula (I), X is NR, O or S, R is a hydrogen atom or a linear or branched alkyl group with 1 to 4 carbons, R ¹ , R ² , R ³ , R ⁴ , R ^5. R ⁶ , R ⁷ and R ⁸ are each independently a straight-chain or branched-chain alkyl group with 1 to 4 carbons, m is each independently any integer from 0 to 5, and n is each independently 0 Any integer of ~4. 〕

[2] A light-emitting device comprising the light-emitting material according to [1].

〔式（II）中， R ¹、R ²、R ³、R ⁴、R ⁵、R ⁶、R ⁷及R ⁸分別獨立地為碳數1～4的直鏈狀或者分支鏈狀的烷基， m分別獨立地為0～5的任意整數，並且 n分別獨立地為0～4的任意整數。〕 [發明的效果] [3] A compound represented by the formula (II). [chemical 5]

[In formula (II), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a straight-chain or branched-chain alkyl group with 1 to 4 carbons , m are each independently any integer of 0-5, and n are each independently any integer of 0-4. 〕 [Effect of Invention]

The boron-containing compound of the present invention is effective as a light emitting material. Among the luminescent materials of the present invention are materials that emit delayed fluorescence. A light-emitting device containing the light-emitting material of the present invention can achieve excellent luminous efficiency.

The boron-containing compound contained in the light-emitting material of the present embodiment is a compound represented by formula (I).

〔式（I）中， X為N-R、O或S， R為氫原子或碳數1～4的直鏈狀或者分支鏈狀的烷基， R ¹、R ²、R ³、R ⁴、R ⁵、R ⁶、R ⁷及R ⁸分別獨立地為碳數1～4的直鏈狀或者分支鏈狀的烷基， m分別獨立地為0～5的任意整數，並且 n分別獨立地為0～4的任意整數。〕 [chemical 6]

[In formula (I), X is NR, O or S, R is a hydrogen atom or a linear or branched alkyl group with 1 to 4 carbons, R ¹ , R ² , R ³ , R ⁴ , R ^5. R ⁶ , R ⁷ and R ⁸ are each independently a straight-chain or branched-chain alkyl group with 1 to 4 carbons, m is each independently any integer from 0 to 5, and n is each independently 0 Any integer of ~4. 〕

The boron-containing compound of the present embodiment is a compound represented by formula (II).

〔式（II）中， R ¹、R ²、R ³、R ⁴、R ⁵、R ⁶、R ⁷及R ⁸分別獨立地為碳數1～4的直鏈狀或者分支鏈狀的烷基， m分別獨立地為0～5的任意整數，並且 n分別獨立地為0～4的任意整數。〕 [chemical 7]

[In formula (II), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a straight-chain or branched-chain alkyl group with 1 to 4 carbons , m are each independently any integer of 0-5, and n are each independently any integer of 0-4. 〕

The alkyl group in R, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ in formula (I) or formula (II) can be straight chain or branched chain . The number of constituent carbon atoms is preferably from one to four. Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

"Alkyl" may have a substituent. Examples of substituents on the "alkyl group" include halogen groups such as fluoro, chloro, bromo, and iodo; hydroxyl; methoxy, ethoxy, n-propoxy, isopropoxy, and n-butyl. Oxygen, second butoxy, isobutoxy, third butoxy and other C1-C6 alkoxy groups; 2-chloro-n-propoxy, 2,3-dichlorobutoxy, trifluoromethoxy C1～C6 haloalkoxy group; phenyl; 4-chlorophenyl, 4-trifluoromethylphenyl, 4-trifluoromethoxyphenyl, etc. through halogen group, C1～C6 haloalkyl or C1～C6 phenyl substituted with haloalkoxy; or cyano.

Specific examples of the boron-containing compound of the present embodiment include the following compounds. However, the present invention is not limited to the exemplified compounds.

[chemical 8]

The boron-containing compound of the present embodiment can be obtained by combining known synthesis reactions (eg, coupling reaction, substitution reaction, etc.) described in Patent Document 1, Patent Document 2, and the like.

Purification of the synthesized compound can be carried out by purification with column chromatography, adsorption purification with silica gel, activated carbon, activated clay, etc., recrystallization or crystallization with a solvent, and the like. Identification of the compound can be performed by nuclear magnetic resonance (nuclear magnetic resonance, NMR) analysis and the like.

The light-emitting material of this embodiment can provide light-emitting elements such as organic photoluminescence elements and organic electroluminescence elements. The boron-containing compound used in the luminescent material of this embodiment has the function of assisting the light emission of other luminescent materials (host materials), so it can be used as doped in other luminescent materials.

Specific examples of the boron-containing compound used in the light-emitting material of the present embodiment include the following compounds in addition to those exemplified as the boron-containing compound of the present embodiment. However, the boron-containing compound used in the light-emitting material of the present invention is not limited to the exemplified compounds.

[chemical 9]

[chemical 10]

The organic photoluminescent element of this embodiment is formed by providing a light-emitting layer containing the light-emitting material of this embodiment on a substrate. The light-emitting layer can be obtained by a coating method such as spin coating, a printing method such as inkjet printing, or a vapor deposition method.

The organic electroluminescent element of this embodiment is formed by providing an organic layer between the anode and the cathode. The "organic layer" in the present specification refers to a layer located between the anode and the cathode and substantially containing an organic substance, and these layers may contain an inorganic substance as long as the performance of the light-emitting device of the present invention is not impaired.

As a structure of one embodiment of the organic electroluminescent element of the present invention, it can be enumerated that the substrate sequentially includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, and an electron transport layer. , the structure of the cathode; and the structure of the electron injection layer between the electron transport layer and the cathode. Several organic layers can be omitted in these multilayer structures, for example, an anode, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode can also be sequentially formed on the substrate, or an anode, a hole transport layer, Light emitting layer, electron transport layer, cathode. The luminescent material of this embodiment can be doped not only in the luminescent layer, but also in the hole injection layer, hole transport layer, electron blocking layer, hole blocking layer, electron transport layer or electron injection layer.

The substrate serves as a support for the light-emitting element, and silicon plates, quartz plates, glass plates, metal plates, metal foils, resin films, resin sheets, and the like can be used. Particularly preferred is a glass plate, or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, or polyester. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. When the gas barrier property of the substrate is too low, the light emitting element may be degraded by the outside air passing through the substrate. Therefore, it is preferable to provide a dense silicon oxide film or the like on either one side or both sides of the synthetic resin substrate to ensure gas barrier properties.

An anode is set on the substrate. The anode generally uses a material with a large work function. Examples of the anode material include metals such as aluminum, gold, silver, nickel, palladium, and platinum; indium oxide, tin oxide, indium tin oxide (ITO), zinc oxide, and In ₂ O ₃ - Metal oxides such as ZnO and IGZO, metal halides such as copper iodide, carbon black, or conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline. The formation of the anode is generally performed by a sputtering method, a vacuum evaporation method, or the like. In addition, in the case of metal particles such as silver, particles such as copper iodide, carbon black, conductive metal oxide particles, conductive polymer fine powder, etc., it can also be dispersed in an appropriate binder resin solution, And coated on the substrate to form the anode. Furthermore, in the case of a conductive polymer, it is also possible to directly form a thin film on the substrate by electrolytic polymerization or coat the conductive polymer on the substrate to form the anode.

The anode can also be formed by laminating two or more different substances. The thickness of the anode varies according to the desired transparency. When transparency is required, it is desirable that the transmittance of visible light is usually 60% or more, preferably 80% or more. In this case, the thickness is usually 10 nm to 1000 nm, preferably 10 nm to 200 nm. nm. In the case of being opaque, the anode can have the same thickness as the substrate. The sheet resistance of the anode is preferably several hundred Ω/□ or more.

As an optional hole injection layer, in addition to porphyrin compounds represented by copper phthalocyanine, naphthalene diamine derivatives, starburst triphenylamine derivatives, and three The above triphenylamine structure is formed by a single bond or a divalent group without heteroatoms. Arylamine compounds such as triphenylamine trimers and tetramers, hexacyanoazine-extended triphenyl General receptive heterocyclic compounds or coating polymer materials. Regarding these materials, a thin film can also be formed by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

As the hole transport material used in the optional hole transport layer, it is preferable that the efficiency of injecting holes from the anode is high, and that the injected holes can be efficiently transported. Therefore, it is preferable that the free potential is small, the transparency to visible light is high, the hole mobility is large, and the stability is excellent, and impurities that become traps are less likely to be generated during production or use. In addition to the above-mentioned general requirements, in consideration of application to in-vehicle displays, it is preferable that the element has higher heat resistance. Therefore, a material having a value of 70° C. or higher as Tg is desirable.

Examples of the optional hole transport layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyaryl alkane derivatives, pyrazole Phenyl derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives , hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers, etc. More specifically, compounds containing a m-carbazolylphenyl group, N,N'-diphenyl-N,N'-bis(m-tolyl)-benzidine (hereinafter abbreviated as TPD), N ,N'-diphenyl-N,N'-bis(α-naphthyl)-benzidine (hereafter, referred to as NPD), N,N,N',N'-quaterphenylbenzidine and other benzidine Derivatives, 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (hereinafter referred to as TAPC), various triphenylamine trimers and tetramers or carbazole derivatives wait. These may be used alone or in combination of two or more. The hole transport layer may be a film with a single-layer structure or a film with a laminated structure. In addition, as the hole injection/transport layer, poly(3,4-ethylenedioxythiophene) (hereinafter referred to as (Poly(3,4-ethylenedioxythiophene), PEDOT))/poly(styrenesulfonic acid ) (hereinafter referred to as (poly(styrene sulfonate), PSS)) and other coating-type polymer materials. Regarding these materials, a thin film can also be formed by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

In addition, in the hole injection layer or the hole transport layer, a material obtained by further p-doping tribromophenylamine antimony hexachloride with respect to the material generally used in the layer can be used, or in its partial structure A polymer compound having a PD structure, etc. As the hole injecting/transporting host material, carbazole derivatives such as CBP, TCTA, and mCP, etc. can be used.

Preferred compounds (hi1) to (hi7) that can be used as hole injection materials are listed below.

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Preferred compounds (ht1) to (ht38) that can be used as hole transport materials are listed below.

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[Chemical 55]

As an optional electron blocking layer, 4,4',4''-tris(N-carbazolyl)triphenylamine (hereinafter referred to as TCTA), 9,9-bis[4-( Carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (hereinafter referred to as mCP), 2,2-bis(4-carbazol-9-ylphenyl ) adamantane (hereinafter referred to as Ad-Cz) and other carbazole derivatives, 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl ]-9H-fluorene, represented by compounds with triphenylsilyl groups and triarylamine structures, and other compounds with electron blocking effects. These may be used alone or in combination of two or more. The electron blocking layer may be a single-layer film or a laminated film. Regarding these materials, a thin film can also be formed by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

Preferred compounds (es1) to (es5) that can be used as electron blocking materials are listed below.

[Chemical 56]

[Chemical 57]

[Chemical 58]

[Chemical 59]

[Chemical 60]

The light-emitting layer is a layer having a function of emitting light by recombining holes and electrons injected from the anode and the cathode to generate excitons. The light-emitting layer can be formed solely from the light-emitting material of this embodiment, or can be formed by doping the light-emitting material of this embodiment into a host material. Examples of host materials include: metal complexes of quinoline derivatives such as tris(8-quinolinolato)aluminum (hereinafter referred to as Alq3), anthracene derivatives, bistyrylbenzene derivatives, pyrene derivatives, etc. compounds, oxazole derivatives, polyphenylene vinylene derivatives, compounds with bipyridyl and o-terphenyl structures, mCP, thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, etc. . Known dopants may be contained in the light emitting layer. Examples of dopants include quinacridone, coumarin, rubrene, anthracene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, aminostyryl derivatives things etc. In addition, phosphorescent emitters such as green phosphorescent emitters such as Ir(ppy)3, blue phosphorescent emitters such as FIrpic and FIr6, and red phosphorescent emitters such as Btp2Ir(acac) can also be used. These may be used alone or in combination of two or more. The light-emitting layer may be a single-layer film or a laminated film. Regarding these materials, a thin film can also be formed by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method. In the case of using a host material, the lower limit of the amount of the light-emitting material of the present embodiment that can be contained in the light-emitting layer is preferably 0.1% by mass, more preferably 1% by mass, and the upper limit is preferably 50% by mass, more preferably 20% by mass, more preferably 10% by mass.

Preferred compounds (e11) to (e140) that can be used as the host material of the light-emitting layer are listed below.

[Chemical 61]

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[chemical 100]

Examples of the optional hole-blocking layer include compounds having bipyridyl and o-triphenyl structures, phenanthroline derivatives such as bathocuproine (abbreviated as BCP hereinafter), or aluminum (III) bismuths. Metal complexes of quinolinol derivatives such as (2-methyl-8-quinoline)-4-phenylphenoxide (hereinafter referred to as BAlq), various rare earth complexes, oxazole derivatives compounds, triazole derivatives, triazine derivatives and other compounds with hole blocking effect. These materials can also serve as materials for the electron transport layer. These may be used alone or in combination of two or more. The hole blocking layer may be a film of a single-layer structure or a film of a laminated structure. Regarding these materials, a thin film can also be formed by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

Preferred compound (hs1) to compound (hs11) that can be used as a hole blocking material are listed below. [Chemical 101]

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As an optional electron transport layer, in addition to metal complexes of quinolinephenol derivatives represented by Alq3 and BAlq, various metal complexes, triazole derivatives, triazine derivatives, Oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoline derivatives, phenanthroline derivatives, silole derivatives, and the like. These may be used alone or in combination of two or more. The electron transport layer may be a single-layer film or a laminated film. Regarding these materials, a thin film can also be formed by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

As the optional electron injection layer, alkali metal salts such as lithium fluoride and cesium fluoride, alkaline earth metal salts such as magnesium fluoride, metal oxides such as aluminum oxide, etc. can be used. selected, it can be omitted.

For the electron injection layer or the electron transport layer, a material obtained by further N-doping a metal such as cesium with respect to a material generally used in the layer can be used.

Preferred compounds (et1) to (et30) usable as electron transport materials are listed below.

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Preferred compounds (ei1) to (ei4) that can be used as electron injection materials are listed below.

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Preferred compounds (st1) to (st5) that can be used as stabilizing materials are listed below.

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The cathode generally uses a material with a small work function. As materials for the cathode, for example: sodium, sodium-potassium alloy, lithium, tin, magnesium, magnesium/copper mixture, magnesium/aluminum mixture, magnesium/indium mixture, aluminum/alumina mixture, indium, calcium, aluminum, silver , lithium/aluminum mixture, magnesium-silver alloy, magnesium-indium alloy, aluminum-magnesium alloy, etc. By using transparent conductive materials, transparent or translucent cathodes can be obtained. The thickness of the cathode is usually 10 nm to 5000 nm, preferably 50 nm to 200 nm. The sheet resistance of the cathode is preferably several hundred Ω/□ or more.

For the protection of the cathode containing metals with low work function, if aluminum, silver, nickel, chromium, gold, platinum and other metal layers with high work function and stable to the atmosphere are further laminated on it, the stability of the element will be increased. , so it is better. In addition, in order to improve the contact between the cathode and the adjacent organic layer (such as electron transport layer or electron injection layer), a cathode interface layer may also be provided between the two. Examples of materials used for the cathode interface layer include aromatic diamine compounds, quinacridone compounds, condensed tetraphenyl derivatives, organosilicon compounds, organophosphorus compounds, compounds having an N-phenylcarbazole skeleton, N - Vinyl carbazole polymers, etc.

The light-emitting element of this embodiment can be applied to any of a single element, an element including a structure arranged in an array, and a structure in which an anode and a cathode are arranged in an X-Y matrix. [Example]

Hereinafter, the present invention will be described in more detail by means of specific examples. However, this invention is not limited at all by the Example shown below.

The compound represented by formula (I) can be obtained as follows.

(Example 1) [Chem. 151]

[Synthesis of 1] 1,3-dibromo-5-methoxybenzene (2.66 g, 10.0 mmol), diphenylamine (4.23 g, 25.0 mmol), palladium acetate ( II) (0.11 g, 0.50 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.44 g, 1.50 mmol), sodium tert-butoxide (2.40 g, 25.0 mmol) and toluene (40 mL), at 110 Stir at °C for 24 hours. Return to room temperature after the reaction, add water and use diatomaceous earth to remove impurities. Thereafter dichloromethane was added and extraction was carried out. Sodium sulfate was added to the organic layer, dried, and purified by column chromatography (hexane:dichloromethane=1:4) to obtain 1 (3.74 g, 85%) as a white solid. ¹ H-NMR (400 MHz, CDCl ₃ , δ): 7.21-7.16 (m, 8H), 7.08-7.05 (m, 8H), 6.95 (t, J=7.4Hz, 4H), 6.43 (t, J= 2.0Hz, 1H), 6.22 (d, J=2.0Hz, 2H), 3.57 (s, 3H)

[Synthesis of 2] 1 (6.63 g, 15.0 mmol) and dichloromethane (50 mL) were placed in a nitrogen-purged flask, and boron tribromide (4.4 mL, 45.0 mmol) was added dropwise at 0°C. Thereafter, it was stirred at room temperature for 12 hours. After the reaction, methanol was added dropwise at 0°C, and dichloromethane and water were added for extraction. Sodium sulfate was added to the organic layer, dried, and purified by column chromatography (hexane:ethyl acetate=1:4) to obtain white solid 2 (3.56 g, 55%). ¹ H-NMR (400 MHz, CDCl ₃ , δ): 7.23-7.18 (m, 8H), 7.08-7.05 (m, 8H), 6.97 (t, J=7.4Hz, 4H), 6.40 (t, J= 1.9Hz, 1H), 6.10 (d, J=1.8Hz, 2H), 4.41 (s, 1H)

[Synthesis of 3] 1,5-dibromo-2,4-difluorobenzene (2.04 g, 7.5 mmol), 2 (7.71 g, 18.0 mmol), potassium carbonate (3.11 g , 22.5 mmol) and triethylene glycol dimethyl ether (75 mL), stirred at 180°C for 48 hours. After the reaction, the temperature was returned to room temperature, and dichloromethane and water were added for extraction. Sodium sulfate was added to the organic layer, dried, concentrated by a rotary evaporator, and the obtained solid was recrystallized from dichloromethane and methanol to obtain a white solid 3 (5.67 g, 70%). ¹ H-NMR (400 MHz, CDCl ₃ , δ): 7.60 (s, 1H), 7.18-7.13 (m, 16H), 7.04-7.01 (m, 16H), 6.97-6.93 (m, 8H), 6.55 ( t, J=2.0Hz, 2H), 6.46 (s, 1H), 6.22 (d, J=2.0Hz, 4H)

[Synthesis of 4] 1,3,5-Tribromobenzene (74.9 g, 238 mmol), diphenylamine (72.4 g, 428 mmol), tris(dibenzylideneacetone) were added to a nitrogen-purged flask ) Dipalladium (0) (4.36 g, 4.76 mmol), 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (1.95 g, 4.76 mmol), sodium tert-butoxide (68.6 g, 714 mmol), and toluene (400 mL), stirred at 110°C for 12 hours. Return to room temperature after the reaction, add water (400 mL) and use diatomaceous earth to remove impurities. Thereafter dichloromethane was added and extraction was carried out. Sodium sulfate was added to the organic layer, dried, and purified by column chromatography (hexane:dichloromethane=1:5) to obtain white solid 4 (36.2 g, 31%). ¹ H-NMR (400 MHz, CDCl ₃ , δ): 7.24-7.20 (m, 8H), 7.06-7.04 (m, 8H), 7.00 (t, J=7.4Hz, 4H), 6.71 (d, J= 2.0Hz, 2H), 6.68 (t, J=2.0Hz, 1H)

[Synthesis of 5] 4 (28.0 g, 57.0 mmol) and diethyl ether (400 mL) were added to a flask replaced with nitrogen, and n-butyllithium (1.6 M, 39 mL, 62.7 mmol). After stirring at -70°C for 1 hour, add sulfur (2.38 g, 74.1 mmol) and stir at room temperature for 12 hours. After the reaction, water (200 mL) was added, and the obtained solid was washed with methanol to obtain white solid 5 (36.2 g, 31%). ¹ H-NMR (400 MHz, CDCl ₃ , δ): 7.21-7.16 (m, 8H), 7.02-6.94 (m, 12H), 6.66 (d, J=2.0Hz, 2H), 6.58 (t, J= 2.0Hz, 1H)

[Synthesis of 6] Add 5 (5.69 g, 12.8 mmol), 1,3-dibromo-4,6-diiodobenzene (3.12 g, 6.40 mmol), tris(dibenzylideneacetone) dipalladium (0) (0.59 g, 0.64 mmol), bis[2-(diphenylphosphino)phenyl] ether (0.34 g, 0.64 mmol), sodium tert-butoxide (2.46 g, 25.6 mmol) and o-xylene (150 mL), stirred at 140°C for 48 hours. After the reaction, it was returned to room temperature, and impurities were removed using diatomaceous earth. Thereafter, dichloromethane and water were added and extracted. Sodium sulfate was added to the organic layer and dried, and impurities were removed by column chromatography (hexane:dichloromethane=1:3). After removing the solvent, the obtained solid was recrystallized from dichloromethane and methanol, and the obtained 6 was used in the following reaction.

[Synthesis of 7] 5 (6.67 g, 15.0 mmol), 1,5-dibromo-2,4-difluorobenzene (8.16 g, 30.0 mmol), potassium carbonate (8.29 g , 60.0 mmol) and triethylene glycol dimethyl ether (100 mL), stirred at 140°C for 12 hours. After the reaction, the temperature was returned to room temperature, and dichloromethane and water were added for extraction. Sodium sulfate was added to the organic layer, dried, and purified by column chromatography (hexane:dichloromethane=1:3) to obtain white solid 7 (3.33 g, 32%). ¹ H-NMR (400 MHz, DMSO-d ₆ , δ): 8.02 (d, J=6.5Hz, 1H), 7.30-7.26 (m, 8H), 7.07-7.04 (m, 12H), 7.03 (t, J=1.1Hz, 1H), 6.56 (t, J=2.0Hz, 1H), 6.36 (d, J=2.0Hz, 2H)

[Synthesis of 8] 7 (3.05 g, 4.4 mmol), 2 (4.54 g, 10.6 mmol), potassium carbonate (1.82 g, 13.2 mmol) and triethylene glycol dimethyl ether were added to a nitrogen-purged flask (100 mL), stirred at 140°C for 12 hours. After the reaction, the temperature was returned to room temperature, and dichloromethane and water were added for extraction. Sodium sulfate was added to the organic layer, dried, and purified by column chromatography (hexane:dichloromethane=1:3) to obtain white solid 8 (2.14 g, 44%). ¹ H-NMR (400 MHz, DMSO-d ₆ , δ): 7.86 (s, 1H), 7.22-7.17 (m, 16H), 7.03-6.95 (m, 24H), 6.61 (t, J=2.0Hz, 1H), 6.59 (s, 1H), 6.36-6.35 (m, 3H), 6.00 (d, J=2.0Hz, 2H)

[Synthesis of BOBO] 3 (3.26 g, 3.00 mmol) and tert-butylbenzene (360 mL) were added to a flask replaced with nitrogen, and n-butyllithium (1.6 M, 5.6 mL, 9.0 mmol). Thereafter, stirring was carried out at 60° C. for 2 hours. Lower the temperature to 0°C, add boron tribromide (0.9 mL, 9.0 mmol) dropwise, and stir at 90°C for 2 hours. Thereafter, pempidine (2.4 mL, 13.5 mmol) was added at 0°C, and stirred at 160°C for 24 hours. After returning to room temperature after the reaction, water and toluene were added for extraction. Sodium sulfate was added to the organic layer, dried, and purified by column chromatography (hexane:dichloromethane=1:2) to obtain BOBO (0.56 g, 20%) as a yellow solid. ¹ H-NMR (400 MHz, CDCl ₃ , δ): 10.17 (s, 1H), 9.12 (dd, J=7.8, 1.5Hz, 2H), 7.52-7.44 (m,6H), 7.39 (t, J= 7.5Hz, 2H), 7.34 (t, J=7.2Hz, 2H), 7.31(s, 1H), 7.25-7.21 (m, 12H), 7.13-7.10 (m, 8H), 7.06 (t, J=7.4 Hz, 4H), 6.80 (d, J=8.5Hz, 2H), 6.70 (d, J=1.8Hz, 2H), 5.79 (d, J=1.8Hz, 2H)

[Synthesis of BOBS] 8 (1.89 g, 1.70 mmol) and tert-butylbenzene (250 mL) were added to a flask replaced with nitrogen, and n-butyllithium (1.6 M, 4.7 mL , 7.48 mmol). Thereafter, stirring was carried out at 60° C. for 3 hours. Lower the temperature to -10°C, add boron tribromide (0.4 mL, 4.10 mmol) dropwise, and stir at room temperature for 2 hours. Thereafter, pentamethylpiperidine (1.2 mL, 6.80 mmol) was added and stirred at 170° C. for 12 hours. After returning to room temperature after the reaction, water and dichloromethane were added for extraction. Sodium sulfate was added to the organic layer, dried, and purified by column chromatography (hexane:dichloromethane=1:3) to obtain BOBS (0.33 g, 20%) as a yellow solid. ¹ H-NMR (400 MHz, DMSO-d ₆ , δ): 9.83 (s, 1H), 8.85 (d, J=7.8Hz, 1H), 8.73 (d, J=6.8Hz, 1H), 7.62 (s , 1H), 7.61-7.52 (m, 6H), 7.50-7.45 (m, 2H), 7.39-7.25 (m, 14H), 7.19-7.08 (m, 12H), 6.75-6.69 (m, 3H), 6.36 (d, J=1.8Hz, 1H), 5.93 (d, J=2.0Hz, 1H), 5.73 (d, J=2.0Hz, 1H)

[Synthesis of BSBS] 6 (1.91 g, 1.70 mmol) and tert-butylbenzene (250 mL) were added to a nitrogen-substituted flask, and n-butyl lithium (1.6 M, 4.7 mL , 7.57 mmol). Thereafter, stirring was carried out at 60° C. for 3 hours. Lower the temperature to -10°C, add boron tribromide (0.4 mL, 4.13 mmol) dropwise, and stir at room temperature for 2 hours. Thereafter, pentamethylpiperidine (1.2 mL, 6.88 mmol) was added and stirred at 170° C. for 12 hours. After returning to room temperature after the reaction, water and dichloromethane were added for extraction. Sodium sulfate was added to the organic layer, dried, and purified by column chromatography (hexane:dichloromethane=1:3) to obtain BSBS (0.23 g, 14%) as a yellow solid. ¹ H-NMR (400 MHz, DMSO-d ₆ , δ): 9.63 (s, 1H), 8.71 (d, J=7.5Hz, 2H), 7.88 (s, 1H), 7.59-7.44 (m, 8H) , 7.34-7.29 (m, 14H), 7.15 (t, J=7.4Hz, 4H), 7.09 (d, J=7.5Hz, 8H), 6.70-6.68 (m, 4H), 5.91 (d, J=1.8 Hz, 2H)

For the evaluation of the luminescence characteristics, a Source Meter (manufactured by Keithley: 2400 series), a spectroradiometer (manufactured by Konica Minolta: CS-2000), a spectrometer A fluorophotometer (manufactured by JASCO Corporation: FP-8600) and a 100 mmΦ integrating sphere (manufactured by JASCO Corporation: ILF-835) were used.

(Example 2) Prepare 10 ^-5 M toluene solutions of BOBO, BOBS or BSBS in a glove box under nitrogen atmosphere. For these solutions, photoluminescence (PL) spectra were measured. The results are shown in Table 1. Figure 1 shows the absorption spectrum. Figure 2 shows the PL spectrum. Figure 3 shows the transient PL characteristics. "IRF" in FIG. 3 represents a device response function.

BOBO: [CH152]

BOBS: [Chem. 153]

BSBS: [Chem 154]

[Table 1]

(Example 3) On a glass substrate formed with an anode (50 nm thick) containing indium-tin oxide (ITO) ^, 10 nm thick 2 ,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) film, 40 nm thick 1,1-bis[ 4-[N,N-bis(p-tolyl)amino]phenyl]cyclohexane (TAPC) film, 10 nm thick mMCP film, 20 nm thick 3 wt% BOBO:mCBP film, 10 nm thick 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF) film, 40 nm thick 1,3-bis[3,5-bis(pyridin-3-yl)benzene base] benzene (B3PyPB) film.

Then, a 1 nm-thick lithium 8-hydroxyquinolate film and a 100 nm-thick aluminum film were sequentially laminated by vacuum evaporation to form a cathode, thereby obtaining an organic electroluminescent element. The characteristics of the organic electroluminescence element were measured. Table 2 shows the emission characteristics. Figure 4 shows the electroluminescence (EL) spectrum. Fig. 5 shows voltage-current density-brightness characteristics. Fig. 6 shows luminance-external quantum efficiency characteristics.

(Example 4) On a glass substrate formed with an anode (50 nm thick) containing indium-tin oxide (ITO), 10 ^nm thick 2 ,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) film, 40 nm thick 1,1-bis[ 4-[N,N-bis(p-tolyl)amino]phenyl]cyclohexane (TAPC) film, 10 nm thick mMCP film, 30 nm thick 3 wt% BOBS:mCBP film, 10 nm thick 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF) film, 30 nm thick 1,3-bis[3,5-bis(pyridin-3-yl)benzene base] benzene (B3PyPB) film.

Then, a 1 nm-thick lithium 8-hydroxyquinolate film and a 100 nm-thick aluminum film were sequentially laminated by vacuum evaporation to form a cathode, thereby obtaining an organic electroluminescent element. The characteristics of the organic electroluminescence element were measured. Table 2 shows the emission characteristics. Fig. 4 shows the EL spectrum. Fig. 5 shows voltage-current density-brightness characteristics. Fig. 6 shows luminance-external quantum efficiency characteristics.

(Example 5) On a glass substrate formed with an anode (50 nm thick) containing indium-tin oxide (ITO) ^, 10 nm thick 2 ,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) film, 40 nm thick 1,1-bis[ 4-[N,N-bis(p-tolyl)amino]phenyl]cyclohexane (TAPC) film, 10 nm thick mMCP film, 30 nm thick 3 wt% BSBS:mCBP film, 10 nm thick 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF) film, 30 nm thick 1,3-bis[3,5-bis(pyridin-3-yl)benzene base] benzene (B3PyPB) film.

Then, a 1 nm-thick lithium 8-hydroxyquinolate film and a 100 nm-thick aluminum film were sequentially laminated by vacuum evaporation to form a cathode, thereby obtaining an organic electroluminescent element. The characteristics of the organic electroluminescence element were measured. Table 2 shows the light emission characteristics. Fig. 4 shows the EL spectrum. Fig. 5 shows voltage-current density-brightness characteristics. Fig. 6 shows luminance-external quantum efficiency characteristics.

[Table 2]

The light-emitting element of the present invention emits narrow-band blue light with high external quantum efficiency. [industrial availability]

A novel boron-containing compound excellent in light-emitting properties, a light-emitting material, and a light-emitting device using the light-emitting material can be provided.

none

FIG. 1 is a graph showing an example of the absorption spectrum of the luminescent material of this embodiment. FIG. 2 is a graph showing an example of the PL spectrum of the light emitting material of the present embodiment. FIG. 3 is a graph showing an example of the transient PL characteristics of the light-emitting material of this embodiment (the left figure is an enlarged view of the right figure). FIG. 4 is a graph showing an example of the EL spectrum of the light emitting element of the present embodiment. FIG. 5 is a graph showing an example of voltage-current density-luminance characteristics of the light-emitting element of the present embodiment. FIG. 6 is a graph showing an example of the luminance-external quantum efficiency characteristic of the light-emitting element of the present embodiment.

Claims (3)

A luminescent material comprising a compound represented by formula (I),

In formula (I), X is NR, O or S, R is a hydrogen atom or a linear or branched alkyl group with 1 to 4 carbons, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a straight-chain or branched-chain alkyl group with 1 to 4 carbons, m is each independently any integer from 0 to 5, and n is each independently 0 to 5 Any integer of 4. A light-emitting element, containing the light-emitting material as claimed in claim 1. A compound represented by formula (II),

In formula (II), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a linear or branched alkyl group with 1 to 4 carbons, m is each independently any integer of 0-5, and n is each independently any integer of 0-4.

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