Boron-nitrogen fused heterocyclic compound, application thereof and organic electroluminescent device containing compound

Abstract

The invention provides a boron-nitrogen-containing organic compound and an application thereof in an organic electroluminescent device. According to the compound, a hydrocarbon condensed ring structure with excellent photoelectric stability is introduced to the periphery of a boron-nitrogen light-emitting core, so that the aging effect in the light-emitting process is effectively inhibited. While high efficiency and high color purity are ensured, the compound of the present invention significantly prolongs the service life of a device.

Description

Technical Field

[0001] The invention relates to the technical field of organic electroluminescence, and in particular to a novel boron-nitrogen fused heterocyclic compound and application thereof, and an organic electroluminescent device containing the compound. Background Art

[0002] Organic light emitting devices (OLEDs) are current-driven thin-film devices with a sandwich-like structure, with a single or multiple layers of organic functional materials sandwiched between the anode and the cathode. Under the action of an electric field, the holes generated by the anode and the electrons generated by the cathode will move, and are injected into the hole transport layer and the electron transport layer respectively, and migrate to the light-emitting layer. When the two meet and recombine in the light-emitting layer, energy excitons are generated, thereby exciting the light-emitting molecules to finally produce visible light. OLEDs have the characteristics of self-luminescence, wide viewing angle, wide color gamut, and short response time. They can be made into large-size and / or flexible ultra-thin panels. They are a new display technology that is developing rapidly and has a high degree of process integration. They have been widely used in display products such as televisions, smart phones, tablets, car displays, and lighting, and will be further used in creative display products such as large-size displays and flexible screens.

[0003] In OLED devices, the guest material doped in the light-emitting layer plays a key role in the luminescence efficiency, device life and luminescence spectrum. In recent years, multi-resonance thermally induced delayed fluorescence (MR-TADF) materials have the characteristics of high luminescence efficiency and narrow half-width, thereby achieving high color purity and high-efficiency OLED performance, which has attracted widespread attention from the scientific research and industry (Adv. Mater. 2016, 28, 2777–2781). It has been reported that a high-efficiency green light-emitting material has been constructed through a multiple "locked ring" structure, which has excellent advantages and strong potential in the display indicators for BT.2020 (Nat Commun 2022, 13, 4876). However, the device life is poor, which limits its further application in the real field. Summary of the invention

[0004] To solve the above problems, the present invention application provides an organic electroluminescent device prepared by a boron-nitrogen organic compound and a method for preparing the same. The compound of the present invention connects a hydrocarbon fused ring structure with excellent photoelectric stability to the periphery of a boron-nitrogen luminescent core, thereby reducing the aging process during the luminescence process, thereby significantly improving the device life while ensuring high efficiency and high color purity.

[0005] Specifically, the present application provides: 1) a boron-nitrogen fused heterocyclic compound for an organic electroluminescent device, wherein the compound is represented by formula (1):

[0006]

[0007] Wherein: R1 to R9 are independently selected from hydrogen atoms, deuterium atoms, fluorine atoms, substituted or unsubstituted alkyl groups having 1 to 50 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 50 carbon atoms, substituted or unsubstituted silyl groups having 1 to 50 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 50 carbon atoms, cyano groups, substituted or unsubstituted aryl groups having 6 to 50 ring carbon atoms, substituted or unsubstituted heteroaryl groups having 4 to 50 ring carbon atoms; a, b, c, d are independently integers of 1 to 3, e, f, g, h are independently integers of 1 to 4; when there are multiple R1 to R8, the multiple R1 to R8 may be the same or different;

[0008] And at least one of R1 to R8 is of the following formula (2):

[0009]

[0010] Wherein: L is phenyl or directly bonded;

[0011] The position where the formula (2) and the formula (1) are bonded

[0012] Where X is:

[0013]

[0014] in: Indicates the position where (X) is bonded to L; the horizontal line indicates R 21 ~R 28 Any single bond in which L is bonded;

[0015] R 21 ~R 28 In the above, except for any single bond to L, each of them is independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a cyano group, or a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms; and R 21 ~R 28 Two adjacent groups can form a ring to form a condensed ring aromatic group with 10-50 carbon atoms;

[0016] The entire molecule may be deuterated or undeuterated.

[0017] 2) According to the boron-nitrogen fused heterocyclic compound described in 1) above, the fused aromatic moiety in the structure of formula (X) is selected from the following structures:

[0018]

[0019] Among them: In each structure, R 21 ~R 32 Except for any single bond to L, each of them is independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a cyano group, or a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms;

[0020] The entire molecule may be deuterated or undeuterated.

[0021] 3) The boron-nitrogen fused heterocyclic compound according to 1) above, wherein R9 is selected from a hydrogen atom, deuterium, an alkyl group having 1 to 10 carbon atoms, a deuterated alkyl group having 1 to 10 carbon atoms, and a fluorine atom.

[0022] 4) The boron-nitrogen fused heterocyclic compound according to 1) or 2), wherein R1-R8 and R 21 -R 32 Each of the following is independently selected from the group consisting of a hydrogen atom, a deuterium atom, a fluorine atom, a cyano group, a substituted silyl group, a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, a substituted or unsubstituted n-propyl group, a substituted or unsubstituted isopropyl group, a substituted or unsubstituted n-butyl group, a substituted or unsubstituted isobutyl group, a substituted or unsubstituted sec-butyl group, a substituted or unsubstituted tert-butyl group, a substituted or unsubstituted 2-methylbutyl group, a substituted or unsubstituted n-pentyl group, a substituted or unsubstituted sec-pentyl group, a substituted or unsubstituted cyclopropyl group, a substituted or unsubstituted cyclobutyl group, a substituted or unsubstituted cyclopentyl group, a substituted or unsubstituted cyclohexyl, substituted or unsubstituted adamantyl, substituted or unsubstituted thienyl, substituted or unsubstituted indolyl, substituted or unsubstituted furanyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted indenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted substituted or unsubstituted naphthphenyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzoselenophene, and substituted or unsubstituted carbazolyl, substituted or unsubstituted deuterated methyl, and substituted or unsubstituted deuterated phenyl.

[0023] 5) The boron-nitrogen-fused heterocyclic compound according to 1) above, wherein the "substituted" in "substituted or unsubstituted" in the compound means that the substituent is independently selected from a deuterium atom, a fluorine atom, a cyano group, a monovalent alkyl group having 1 to 10 carbon atoms, or a cycloalkyl group.

[0024] 6) The fused heterocyclic compound according to 1) above, wherein the fused heterocyclic compound is selected from the following structures:

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] 7) An organic electroluminescent device, wherein the organic electroluminescent device comprises an anode, a cathode and at least one organic thin film located between the anode and the cathode, and the organic thin film contains the compound described in any one of 1) to 6) above.

[0039] 8) The organic electroluminescent device according to 7) above, wherein the compound is used as a light-emitting material in the organic electroluminescent device.

[0040] The beneficial technical effects of the present invention are:

[0041] (1) The compounds of the present invention are applied to organic light-emitting diodes and can be used as doping materials for light-emitting layer materials. They can emit green fluorescence under the action of an electric field and can be applied to the fields of OLED lighting or OLED display.

[0042] (2) When the compound of the present invention is used as a light-emitting doping material of the light-emitting layer of an organic electroluminescent diode, it can significantly improve the device life while maintaining high efficiency and high color purity, and has great application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the structure of an OLED device in which the materials listed in the present invention are applied. DETAILED DESCRIPTION

[0044] the term

[0045] In the present invention, the alkyl group may be linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, and is, for example, 1 to 50, preferably 1 to 20, and more preferably 1 to 6. Specific examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethylpropyl, 1,1-dimethylpropyl, isohexyl, 4-methylhexyl, and 5-methylhexyl.

[0046] Alkoxy refers to -O-alkyl, wherein the number of carbon atoms is not particularly limited, for example, 1 to 50, preferably 1 to 20, more preferably 1 to 6. Examples of alkoxy include, but are not limited to, methoxy, ethoxy, propoxy (eg, n-propoxy and isopropoxy), and tert-butoxy.

[0047] In the present invention, the above-mentioned alkyl or alkoxy group may be substituted. For example, in the fluorinated alkyl group and the fluorinated alkoxy group substituted with fluorine, the number of carbon atoms is not particularly limited, for example, 1 to 20, more preferably 1 to 6. Examples of fluorinated alkyl groups include, but are not limited to, fluoromethyl, difluoromethyl, trifluoromethyl, trichloromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, and heptafluoropropyl. Examples of fluorinated alkoxy groups include, but are not limited to, trifluoromethoxy, 2,2,2-trifluoroethoxy, and pentafluoroethoxy.

[0048] The cycloalkyl group may be a monocyclic ring or a condensed ring, and the number of carbon atoms therein is not particularly limited, and is, for example, 3 to 50, preferably 3 to 20, and more preferably 3 to 6. Specific examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and adamantyl, and preferably cyclopentyl, cyclohexyl, and adamantyl.

[0049] The aryl group may be a monocyclic or polycyclic aryl group, wherein the number of carbon atoms is not particularly limited, for example, 6 to 50, preferably 6 to 20. Examples of monocyclic aryl groups include, but are not limited to, phenyl, biphenyl and terphenyl. Examples of polycyclic aryl groups include naphthyl, anthracenyl, phenanthrenyl, pyrenyl, perylenyl, tetraphenyl, fluorenyl, acenaphthenyl, triphenylene and fluoranthene, but the scope of the present invention is not limited thereto. Heteroaryl refers to an aryl group containing other elements (such as nitrogen, oxygen, sulfur, etc.) replacing carbon atoms in the aromatic ring. There is no particular limitation on the number of carbon atoms, for example, 2 to 50, preferably 4 to 20.

[0050] "Heterocyclyl" refers to a cyclic compound group in which one or more atoms in the ring are replaced by heteroatoms other than carbon (such as nitrogen, oxygen, sulfur, etc.). A fused-ring heteroaryl group refers to a cyclic compound group in which at least two rings (at least one of which is an aromatic ring) share one or more carbon atoms, and at least one ring contains one or more heteroatoms. Examples of heterocyclic groups and fused-ring heteroaryl groups include, but are not limited to, thienyl, furanyl, pyrrolyl, imidazolyl, triazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidyl, triazinyl, triazolyl, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothienyl, dibenzothienyl, benzofuranyl, dibenzofuranyl, thiazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, benzothiazolyl, and phenothiazinyl.

[0051] Silyl is intended to include alkyl-substituted silyl and aryl-substituted silyl. Specific examples of such silyl include trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, dimethylphenylsilane, triphenylsilyl, trimethoxysilyl, dimethoxyphenylsilyl, diphenylmethylsilyl, diphenylvinylsilyl, methylcyclobutylsilyl, and dimethylfurylsilyl.

[0052] "Deuterated", such as "deuterated or not deuterated", refers to one or more deuterated or fully deuterated.

[0053] Synthesis Example

[0054] Synthetic route

[0055]

[0056] Synthesis steps

[0057] Synthesis of intermediate A1: Weigh 7.0g (25mmol) of di-tert-butylcarbazole, 9.5g (25mmol) of 2,4-dibromo-5-fluoroiodobenzene, and 9.8g (30mmol) of cesium carbonate in a flask, add 80ml of dry N,N-dimethylformamide, purify, and react at 140℃ for 6h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 200ml of water, precipitate a yellow solid, and filter. Collect the solid, separate and purify with a silica gel column to obtain 13.7g of product with a yield of 86%. The molecular weight measured by mass spectrometry is m / z=639.1 (M) +

[0058] Synthesis of intermediate B1: Weigh 12.7g (20mmol) of intermediate A1, 3.7g (25mmol) of 4-tert-butylaniline, 0.95g (1mmol) of tris(dibenzylideneacetone)dipalladium, 1.1g (2mmol) of DPPF, and 2.95g (30mmol) of sodium tert-butoxide into a flask, add 200ml of toluene, vent, and react at 110°C under nitrogen protection for 20h. Stop the reaction, cool to room temperature, extract with ethyl acetate and water, and concentrate by rotary evaporation. Then separate and purify with a silica gel column to obtain about 9.64g of product with a yield of 73%. The molecular weight measured by mass spectrometry is m / z=660.4 (M) +

[0059] Synthesis of intermediate C1: Weigh 9.24g (14mmol) of intermediate B1 into a flask, add 100ml of anhydrous THF, protect with nitrogen, slowly add 0.38g (16mmol) of sodium hydride, react at room temperature for 10min, then add 3.92g (18mmol) of di-tert-butyl dicarbonate, react at 70℃ for 6h. Stop the reaction, cool to room temperature, extract with ethyl acetate and water, and concentrate by rotary evaporation. Then separate and purify with silica gel column to obtain about 9.9g of product, with a yield of 70%

[0060] Synthesis of intermediate D1: Weigh 7.6g (10mmol) of intermediate C1 and dissolve it in dry tetrahydrofuran, and stir at -78℃ for 10 minutes. Under nitrogen protection, add 8.4ml of n-butyl lithium in n-hexane solution (21mmol, 2.5M) to the reaction solution. After the addition is complete, keep stirring at low temperature for 1h. At -78℃, weigh 4.14g (23mmol) of 9-fluorenone and add it to the reaction solution, return to room temperature naturally, and react for 10h. Add 20ml of water to quench the reaction, extract with ethyl acetate / water three times, collect the organic phase, remove the solvent by rotary evaporation, and separate with silica gel column to obtain the crude product. Dissolve the crude product in 50ml of dichloromethane, stir at room temperature, and under nitrogen protection, add 1.2ml (10mmol) of boron trifluoride ether. Stir at room temperature for 1h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 4.88 g of intermediate D1 with a yield of 59%. The molecular weight measured by mass spectrometry was m / z=827.0 (M) +

[0061] Synthesis of intermediate E1: Weigh 8.27g (10mmol) of intermediate D1, 3.8g (12mmol) of 2-bromo-4-chloro-1-iodobenzene, 0.45g (0.5mmol) of tris(dibenzylideneacetone)dipalladium, 1.1g (2mmol) of DPPF, and 1.9g (20mmol) of sodium tert-butoxide in a flask, add 80ml of toluene, vent, and reflux at 110°C for 24h under nitrogen protection. Stop the reaction, cool to room temperature, extract with dichloromethane and water, and concentrate by rotary evaporation. Then separate and purify with a silica gel column to obtain about 5.38g of product with a yield of 53%. The molecular weight measured by mass spectrometry is m / z=1016.4 (M) +

[0062] Synthesis of intermediate F1: Weigh 5.0g (5mmol) of intermediate D1, 0.045g (0.2mmol) of palladium acetate, 0.11g (0.4mmol) of tricyclohexylphosphine, and 2.1g (15mmol) of potassium carbonate in a flask, add 60ml of DMAc, evacuate, and react at 140°C for 24h under nitrogen protection. Stop the reaction, cool to room temperature, add 50ml of water to precipitate solids, and collect the filter cake by filtration. Then separate and purify with a silica gel column to obtain about 3.04g of product with a yield of 65%. The molecular weight measured by mass spectrometry is m / z = -935.3 (M) +

[0063] Synthesis of intermediate G1: Weigh 9.35g (10mmol) of intermediate F1 and 1.98g (11mmol) of NBS in a flask, add 30ml of chloroform, heat at 60℃ for 5h, stop the reaction, cool to room temperature, extract with dichloromethane and water, and concentrate the organic phase by rotary evaporation. Then separate and purify with silica gel column to obtain about 8.8g of product with a yield of 87%. The molecular weight measured by mass spectrometry is m / z=1014.3 (M) +

[0064] Synthesis of intermediate H1: Weigh 6.07g (6mmol) of intermediate G1 and dissolve it in 40ml of dry xylene, protect with nitrogen, add 3.2ml of n-butyl lithium solution (8mmol, 2.5M) at -20℃, stir at low temperature for 1h, and stir at room temperature for 1h. Return to -20℃, add 3.0g (12mmol) of boron tribromide, stir at low temperature for 1h, and stir at room temperature for 2h. Add 2.3g (18mmol) of diisopropylethylamine, heat to 110℃ and react for 6h. Stop the reaction, cool to room temperature, add sodium carbonate solution to neutralize to neutrality, extract with dichloromethane three times, collect the organic phase, spin dry the solvent, separate the crude product with silica gel column, and then recrystallize with dichloromethane / ethanol to obtain 1.41g of the target product. Orange-red solid, yield 25%, mass spectrometry measured molecular weight m / z = -943.3 (M) + According to a similar synthesis method, the corresponding intermediate structure can be synthesized by replacing the raw materials with other structures in the table.

[0065]

[0066]

[0067] Synthesis Example 1

[0068]

[0069] Synthesis of Chemical 3: Weigh 0.94g (1mmol) of intermediate H1, 0.19g (1.5mmol) of 1-naphthaleneboronic acid, 0.04g (0.05mmol) of tris(dibenzylideneacetone)dipalladium, 0.09g (0.2mmol) of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, and 0.35g (2.5mmol) of potassium carbonate into a flask, add 10ml of toluene, 1ml of ethanol, and 1ml of water, ventilate, protect with nitrogen, and react at 90°C for 12h. Stop the reaction, extract with dichloromethane and water, concentrate by rotary evaporation, separate and purify by silica gel column, and obtain about 0.89g of the target product with a yield of 86%. The molecular weight measured by mass spectrometry is m / z=1035.1 (M). +

[0070] Referring to the synthesis method of Synthesis Implementation 1, the corresponding target structure can be obtained by replacing the intermediates and raw materials with the structures in the table.

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077] Synthesis Example 23:

[0078]

[0079] Synthesis of intermediate I1: Weigh 7.0g (25mmol) of di-tert-butylcarbazole, 3.83g (12mmol) of 2-bromo-4-iodo-1,5-difluorobenzene, and 9.8g (30mmol) of cesium carbonate in a flask, add 80ml of dry N,N-dimethylformamide, evacuate the air, and react at 140°C for 6h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 200ml of water, precipitate a yellow solid, and filter. Collect the solid, separate and purify it with a silica gel column, and obtain 8.13g of product with a yield of 81%. The molecular weight measured by mass spectrometry is m / z = -837.6 (M) +

[0080] Synthesis of intermediate J1: Weigh 8.36g (10mmol) of intermediate C1 and dissolve it in dry tetrahydrofuran, and stir at -78℃ for 10 minutes. Under nitrogen protection, add 4ml of n-butyl lithium in n-hexane solution (10mmol, 2.5M) to the reaction solution. After the addition is complete, keep stirring at low temperature for 1h. At -78℃, weigh 2.34g (13mmol) of 9-fluorenone and add it to the reaction solution, return to room temperature naturally, and react for 10h. Add 20ml of water to quench the reaction, extract with ethyl acetate / water three times, collect the organic phase, remove the solvent by rotary evaporation, and separate with silica gel column to obtain the crude product. Dissolve the crude product in 50ml of dichloromethane, stir at room temperature, and under nitrogen protection, add 1.2ml (10mmol) of boron trifluoride ether. Stir at room temperature for 1h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 6.03 g of intermediate J1 with a yield of 69%. The molecular weight measured by mass spectrometry was m / z = -874.1 (M) +

[0081] Synthesis of intermediate K1: Weigh 8.74g (10mmol) of intermediate J1 and dissolve it in dry tetrahydrofuran, and stir at -78℃ for 10 minutes. Under nitrogen protection, add 4ml of n-butyl lithium in n-hexane solution (10mmol, 2.5M) to the reaction solution. After the addition is complete, keep stirring at low temperature for 1h. At -78℃, weigh 2.34g (13mmol) of 2-chloro-9-fluorenone and add it to the reaction solution, return to room temperature naturally, and react for 10h. Add 20ml of water to quench the reaction, extract with ethyl acetate / water three times, collect the organic phase, remove the solvent by rotary evaporation, and separate with silica gel column to obtain the crude product. Dissolve the crude product in 50ml of dichloromethane, stir at room temperature, and under nitrogen protection, add 1.2ml (10mmol) of boron trifluoride ether. Stir at room temperature for 1h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 6.53 g of intermediate K1 with a yield of 66%. The molecular weight measured by mass spectrometry was m / z = 991.8 (M) +

[0082] Synthesis of intermediate L1: Weigh 9.35g (10mmol) of intermediate K1 and 1.98g (11mmol) of NBS in a flask, add 30ml of chloroform, heat at 60℃ for 5h, stop the reaction, cool to room temperature, extract with dichloromethane and water, and concentrate the organic phase by rotary evaporation. Then separate and purify with silica gel column to obtain about 9.0g of product with a yield of 84%. The molecular weight measured by mass spectrometry is m / z = -1070.6 (M) +

[0083] Synthesis of intermediate M1: Weigh 6.07g (6mmol) of intermediate L1 and dissolve it in 40ml of dry xylene, protect with nitrogen, add 3.2ml of n-butyl lithium solution (8mmol, 2.5M) at -20℃, stir at low temperature for 1h, and stir at room temperature for 1h. Return to -20℃, add 3.0g (12mmol) of boron tribromide, stir at low temperature for 1h, and stir at room temperature for 2h. Add 2.3g (18mmol) of diisopropylethylamine, heat to 110℃ and react for 6h. Stop the reaction, cool to room temperature, add sodium carbonate solution to neutralize to neutrality, extract with dichloromethane three times, collect the organic phase, spin dry the solvent, separate the crude product with silica gel column, and then recrystallize with dichloromethane / ethanol to obtain 1.54g of the target product. Orange-red solid, yield 23%, mass spectrometry measured molecular weight m / z = -999.4 (M) +

[0084]

[0085] Synthesis of Chemical 190: Weigh 1.0 g (1 mmol) of intermediate H1, 0.19 g (1.5 mmol) of 2-naphthaleneboronic acid, 0.04 g

[0086] (0.05mmol) tris(dibenzylideneacetone)dipalladium, 0.09g (0.2mmol) 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 0.35g (2.5mmol) potassium carbonate were placed in a flask, 10ml toluene, 1ml ethanol, 1ml water were added, the mixture was vented, nitrogen was protected, and the reaction was carried out at 90°C for 12h. The reaction was stopped, extracted with dichloromethane and water, concentrated by rotary evaporation, and separated and purified by silica gel column to obtain about 0.90g of the target product with a yield of 83%. The molecular weight measured by mass spectrometry was m / z = -1091.2 (M) +

[0087] By referring to the synthesis method of Synthesis Implementation 23 and replacing the intermediates and raw materials with the structures in the table, the corresponding target structure can be obtained.

[0088]

[0089] Device Example:

[0090] A 50 mm × 50 mm × 0.7 mm thick glass substrate with an indium tin oxide / silver / indium tin oxide (ITO / Ag / ITO) anode was ultrasonically cleaned in isopropyl alcohol for 5 minutes. The cleaned glass substrate was mounted on a substrate rack of a vacuum evaporation device and evacuated to 1×10 -5 ~1×10 -6Pa, before evaporating the organic material, treat with nitrogen plasma for 120 seconds. Then co-evaporate HT and HI as a doping on the anode as a hole injection layer (HIL), with a film thickness of 10nm, where the doping concentration of HI is 3%. Evaporate HT on the hole injection layer as a hole transport layer (HTL), with a film thickness of 135nm. Then, evaporate EB on the hole transport layer as an electron blocking layer (EBL), with a film thickness of 40nm. Then, co-evaporate the light-emitting layer (EML) on the electron blocking layer, with a film thickness of 40nm; the light-emitting layer (EML) adopts a multi-source co-evaporation method to evaporate the main material, sensitizer material and light-emitting material (GH-P / GH-N, PGD and FGD) of the light-emitting layer, where the main material is GH-P:GH-N in a ratio of 6:4, the doping concentration of the sensitizer is 8%, and the doping concentration of the light-emitting material is 1%. Then evaporate HB on the light-emitting layer as a hole blocking layer (HBL), with a film thickness of 5nm. Then, on the hole blocking layer, electron transport material (ET) and 8-hydroxyquinoline lithium (Liq) were co-deposited in a 1:1 ratio as an electron transport layer (ETL) with a film thickness of 30 nm. In addition, LiF was evaporated on the ETL as an electron injection layer (EIL) with a film thickness of 1 nm. Then, metal magnesium / silver (Mg / Ag) was co-evaporated on the EIL with a film thickness of 13.2 nm, wherein the doping concentration of magnesium was 10%. Finally, CP was evaporated as a light coupling layer (CPL) with a film thickness of 70 nm. The fabricated device was transferred to a glove box and encapsulated with a glass cover. The structure of the organic electroluminescent device of Example 1 is shown in FIG. Figure 1 As shown, Figure 1 The stacking order and role of each functional layer are also shown.

[0091] The OLED has in principle the following layer structure: ITO / Ag / ITO substrate / hole injection layer (HIL) / hole transport layer (HTL) / electron blocking layer (EBL) / luminescent layer (EML) / hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL) / cathode / light coupling layer (CPL). The exact structure of the OLED is shown in Table 3.

[0092] Table 3 Materials used for OLED

[0093]

[0094]

[0095] Device Example 1:

[0096] ITO / Ag / ITO / HT:HI(10nm,3%) / HT(135nm) / EB(40nm) / GH-P:GH-N:PGD:FGD(40nm,(GH-P:G H-N=6:4),8%,1%) / HB(5nm) / ET:Liq(30nm,50%) / LiF(1nm) / Ag:Mg(13.2nm,10%) / CP(70nm)

[0097] The FGD used in the light-emitting layer of device example 1 is chemical 1 of the present invention;

[0098] The only difference between device examples 2-25 and device example 1 is that the FGD of the present invention used in the light-emitting layer is replaced by other compounds of the present invention. The performance test data of the obtained devices are shown in Table 4.

[0099] Comparative Examples 1 to 4:

[0100] Compared with device embodiment 1, this comparative example is different in that the FGD in the organic electroluminescent device is changed to Ref-1, Ref-2, Ref-3, and Ref-4 known in the industry. The obtained device performance test data are shown in Table 4.

[0101] The OLEDs were characterized by standard methods. For this purpose, the electroluminescence spectrum and the external quantum efficiency (EQE, measured in %) were determined, which was calculated as a function of the luminous density from a current / voltage / luminous density characteristic (IUL characteristic) exhibiting Lambertian emission characteristics. The EQE is expressed at a current density of 10 mA / cm 2 The external quantum efficiency of the device under the current density of 50mA / cm 2 The peak value represents the working time when the device brightness decreases to 90% under the current density of 10mA / cm 2 The device performances of Examples 1 to 25 of the present invention and Comparative Examples 1 to 3 are summarized in Table 4;

[0102] Table 4 Device performance

[0103]

[0104]

[0105] As can be seen from Table 4, compared with the prior art, the material embodiments 1-25 of the present invention can all show green light emission. The luminous efficiency of OLED devices is improved to a certain extent, and the device life is significantly improved. For example, relative to Comparative Example 1, the device EQE efficiency of the device embodiment 2 where chemical 3 is located is improved by 4.2%, and the T90 life is improved by 55.7%. Relative to Comparative Example 2, the device efficiency of embodiment 18 where chemical 172 is located is improved by 3.2%, and the life is improved by 30.2%. Relative to Comparative Example 3, the device efficiency of device embodiment 8 where chemical 31 is located is improved by 1.1%, and the life is improved by 19.1%. Relative to Comparative Example 4, the device efficiency of device embodiment 13 where chemical 139 is located is improved by 5.2%, and the life is improved by 26.6%. It can be seen that the introduction of a hydrocarbon fused ring structure in the periphery of the luminescent core of the compound of the present invention has a significant improvement in life. The reason may be that the hydrocarbon fused ring structure has excellent photoelectric stability, which is conducive to reducing the aging and deterioration of the luminescent molecules, thereby improving the life of the OLED device.

[0106] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A boron-nitrogen fused heterocyclic compound for an organic electroluminescent device, characterized in that: The compound is represented by formula (1): Wherein: R1 to R9 are independently selected from hydrogen atoms, deuterium atoms, fluorine atoms, substituted or unsubstituted alkyl groups having 1 to 50 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 50 carbon atoms, substituted or unsubstituted silyl groups having 1 to 50 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 50 carbon atoms, cyano groups, substituted or unsubstituted aryl groups having 6 to 50 ring carbon atoms, substituted or unsubstituted heteroaryl groups having 4 to 50 ring carbon atoms; a, b, c, d are independently integers of 1 to 3, e, f, g, h are independently integers of 1 to 4; when there are multiple R1 to R8, the multiple R1 to R8 may be the same or different; And at least one of R1 to R8 is of the following formula (2): Wherein: L is phenyl or directly bonded; is the bonding position between formula (2) and formula (1) Where X is: in: Indicates the position where (X) is bonded to L; the horizontal line indicates R 21 ~R 28 Any single bond in which L is bonded; R 21 ~R 28 In the above, except for any single bond to L, each of them is independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a cyano group, or a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms; and R 21 ~R 28 Two adjacent groups can form a ring to form a condensed ring aromatic group with 10-50 carbon atoms; The entire molecule may be deuterated or undeuterated.

2. The boron-nitrogen fused heterocyclic compound according to claim 1, wherein the fused aromatic moiety of the structure of formula (X) is selected from the following structures: in: In each structure, R 21 ~R 32 Except for any single bond to L, each of them is independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a cyano group, or a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms; The entire molecule may be deuterated or undeuterated.

3. The boron-nitrogen fused heterocyclic compound according to claim 1, characterized in that: The R9 is selected from a hydrogen atom, a deuterium, an alkyl group having 1 to 10 carbon atoms, a deuterated alkyl group having 1 to 10 carbon atoms, and a fluorine atom.

4. The boron-nitrogen fused heterocyclic compound according to claim 1 or 2, characterized in that: R1-R8 and R 21 -R 32 Each of the following is independently selected from the group consisting of a hydrogen atom, a deuterium atom, a fluorine atom, a cyano group, a substituted silyl group, a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, a substituted or unsubstituted n-propyl group, a substituted or unsubstituted isopropyl group, a substituted or unsubstituted n-butyl group, a substituted or unsubstituted isobutyl group, a substituted or unsubstituted sec-butyl group, a substituted or unsubstituted tert-butyl group, a substituted or unsubstituted 2-methylbutyl group, a substituted or unsubstituted n-pentyl group, a substituted or unsubstituted sec-pentyl group, a substituted or unsubstituted cyclopropyl group, a substituted or unsubstituted cyclobutyl group, a substituted or unsubstituted cyclopentyl group, a substituted or unsubstituted cyclohexyl, substituted or unsubstituted adamantyl, substituted or unsubstituted thienyl, substituted or unsubstituted indolyl, substituted or unsubstituted furanyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted indenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted substituted or unsubstituted naphthphenyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzoselenophene, and substituted or unsubstituted carbazolyl, substituted or unsubstituted deuterated methyl, and substituted or unsubstituted deuterated phenyl.

5. The boron-nitrogen fused heterocyclic compound according to claim 1, characterized in that: The "substituted" in "substituted or unsubstituted" in the above-mentioned compound means that the substituent is independently selected from a deuterium atom, a fluorine atom, a cyano group, a monovalent alkyl group having 1 to 10 carbon atoms, or a cycloalkyl group.

6. The fused heterocyclic compound according to claim 1, characterized in that: The fused heterocyclic compound is selected from the following structures:

7. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode, a cathode and at least one organic thin film between the anode and the cathode, wherein the organic thin film contains the compound according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that: The compound is used as a light-emitting material in an organic electroluminescent device.

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