Boron-nitrogen compound and organic electroluminescent device thereof

Abstract

The invention belongs to the technical field of organic electroluminescent materials, and particularly relates to a boron-nitrogen compound and an organic electroluminescent device of the boron-nitrogen compound. Through conjugate extension and heteroatom doping, a multi-plane distributed three-dimensional space structure which is connected by aryl or heteroaryl and has resonance cores on two sides is constructed, the energy level and the molecular accumulation behavior can be synchronously regulated and controlled, and intramolecular charge transfer (ICT) and resonance effect in an excited state are maintained while concentration quenching is inhibited. The compound has good film-forming property and excellent luminous efficiency.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent materials technology, and particularly relates to a boron-nitrogen compound and its organic electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have become a core technology in fields such as smartphones, wearable devices, and automotive displays due to their self-emissive properties, wide viewing angle, broad color gamut, and ultra-thin flexibility. Their light-emitting mechanism relies on the injection and recombination of charge carriers in a multilayer thin-film structure, where the molecular design of the light-emitting layer material plays a decisive role in the device's efficiency, color purity, and lifetime.

[0003] In recent years, thermally activated delayed fluorescence (TADF) materials have attracted much attention due to their ability to achieve 100% exciton utilization through reverse intersystem crossing. Multiple resonance TADF (MR-TADF) materials, by constructing a rigid planar conjugated framework using boron / nitrogen and other multiple resonance nuclei, further compress the full width at half maximum (FWHM) to below 20 nm, significantly improving color purity and device efficiency (e.g., the external quantum efficiency of the blue-green light material DABNA-1 exceeds 30%). However, the molecular design of existing MR-TADF materials relies excessively on planar fused-ring structures, which presents several problems: (1) Concentration quenching and efficiency decay caused by molecular planarity. Although the rigid planar conjugated system of MR-TADF materials is conducive to high radiative transition rates (>10), 6 s -1 However, this also leads to excessively strong intermolecular π-π packing interactions. In high-concentration or solid-state thin films, this close packing exacerbates exciton nonradiative transitions, triggering severe concentration quenching effects and significantly reducing device efficiency and operational stability. Furthermore, the rigidity of the planar structure limits the ability to suppress molecular vibrational relaxation, exacerbating the efficiency roll-off problem, especially in high-energy light-emitting systems such as blue light.

[0004] (2) The lack of three-dimensional spatial control and insufficient flexibility and adaptability, the rigidity of the planar fused ring structure leads to poor material solubility and low film uniformity, making it difficult to be compatible with low-cost solution processing technology (such as inkjet printing). At the same time, the uneven distribution of mechanical stress of planar molecules on the flexible substrate can easily cause film cracks and efficiency decay, which limits the reliability and service life of fully flexible OLED devices.

[0005] Therefore, breaking through the constraints of planarity and developing novel molecular designs that combine three-dimensional configuration with strong multiple resonance effects has become the key to realizing high-efficiency and high-stability MR-TATF materials. Summary of the Invention

[0006] To address the problems existing in the background art, the present invention provides a boron-nitrogen compound having the structure shown in general formula I: ; One of X1 and X2 is B and the other is N; one of X3 and X4 is B and the other is N; Y1 and Y2 may be the same or different, and each is independently selected from single bond, CR1R2, O, S, Se, S(=O)2, =C(CN)2; R1 and R2 are each independently selected from C1 to C2. 30 Alkyl or C6~C 30 aryl; Ar is selected from alkyl-substituted C6~C 30 aryl or C3~C 30 Mixed aromatic compounds.

[0007] As a preferred embodiment of the present invention, X1 is N and X2 is B.

[0008] As a preferred embodiment of the present invention, X4 is N and X3 is B.

[0009] As a preferred embodiment of the present invention, one of the Y1 is a single bond.

[0010] As a preferred embodiment of the present invention, one of the Y2 bonds is a single bond.

[0011] As a preferred embodiment of the present invention, R1 and R2 are each independently selected from C1 to C2. 12 Chain-like alkyl groups.

[0012] As a preferred embodiment of the present invention, the Ar is phenyl, naphthyl, pyridyl, or pyrimidinyl.

[0013] As a preferred embodiment of the present invention, the specific structure of the compound is as follows: ; ; ; ; ; .

[0014] Another object of the present invention is to provide an organic electroluminescent device, comprising a light-emitting layer containing the aforementioned boron-nitrogen compound.

[0015] As a preferred embodiment of the present invention, the organic electroluminescent device is used to manufacture display devices, lighting sources, signal lights, and signs. The display devices include mobile phone displays, computer displays, television displays, smartwatch displays, smart car display panels, and VR or AR helmet displays.

[0016] The beneficial effects of this invention are as follows: The boron-nitrogen compounds provided by this invention, while retaining multiple resonance nuclei, construct a three-dimensional spatial structure with multiplanar distribution of resonance nuclei on both sides, connected by aryl or heteroaryl groups, through conjugated extension and heteroatom doping (see...). Figure 1 It can simultaneously regulate energy levels and molecular stacking behavior, maintaining intramolecular charge transfer (ICT) and resonance effect in the excited state while suppressing concentration quenching, and has good film-forming properties and excellent luminescence efficiency. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a 3D rendering of compound 1. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Unless otherwise specified in the examples, the conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified were all commercially available products. Some reaction compounds were purchased from a supplier (Zhengzhou Alpha Chemical Co., Ltd.), while some compounds that could not be directly purchased were prepared by simple reactions from commercially available raw materials. Percentages refer to mass percentages, and temperatures are in degrees Celsius (°C). The principles, procedures, standard post-treatments, silica gel column chromatography, and recrystallization purification methods of this type are well-known to those skilled in the art and can be fully implemented to obtain the target product. The reactions in the preparation examples were generally carried out under positive pressure of nitrogen or argon.

[0020] Preparation Examples

[0021] ; Synthesis of 1-2: Under a nitrogen atmosphere, n-butyllithium (n-BuLi) (1.6M, 2.30mL) was slowly added dropwise to a dry n-butylbenzene (t-BuPh) (80mL) solution of 1-1 (g 1.18, 3.68mmol). The reaction was carried out at 0℃ for 2h. A solution of dimethyl ketone (0.2g, 3.68mmol) in n-butylbenzene (20mL) was slowly added dropwise. The mixture was then allowed to warm naturally to room temperature. The reaction was quenched with water. The organic solvent layer was removed by rotary evaporation. The crude product was purified by alumina column chromatography (ethyl acetate: petroleum ether - 1:10). It was recrystallized with tetrahydrofuran (THF) and methanol. The crystals were dissolved in acetic acid (370mL) solution and slowly added dropwise with hydrochloric acid (3.7mL). After stirring for 10min, the mixture was rapidly filtered under vacuum to obtain a filter cake. The filter cake was washed with methanol and then recrystallized with THF and methanol to obtain 1-2 (0.68g, 65%). Synthesis of 1-3: At room temperature, bromine water (12.78 g, 80 mmol) was added to a solution of 1-2 (4.53 g, 16 mmol) in dichloromethane (DCM) (80 mL). After 2 h, potassium carbonate (K2CO3) (2.21 g, 16 mmol) was added, and the mixture was stirred for another 22 h. The reaction was quenched with saturated sodium sulfite solution, and the aqueous layer was washed three times with DCM. The organic solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography (DCM as eluent). Recrystallization from DCM and methanol yielded 1-3 (4.04 g, 70%). Synthesis of 1-5: Under a nitrogen atmosphere, n-BuLi (1.6 M, 1.83 mL) was slowly added dropwise to a dry t-BuPh (50 mL) solution (2.12 g, 5.86 mmol) of 1-3, and the reaction was carried out at 0 °C for 2 h. Boron tribromide (BBr3) (2.94 g, 11.72 mmol) was added, and the reaction was carried out at room temperature for 1 h. N,N-diisopropylethylamine (DIEA) (1.23 mL, 7.03 mmol) was added at 0 °C, and the reaction was carried out at 180 °C for 10 h. 1-4 (1.2 M, 10 mL) was added dropwise to the reaction system at room temperature, and after reacting for 2 h, 150 mL of toluene was added. After removing the ether solvent under vacuum, an acidic buffer solution (pH 4.6, 450 mL) was added, and the aqueous phase was washed three times with DCM. The organic solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography (DCM / petroleum ether-1:6). It was recrystallized from DCM and methanol to give 1-5 (0.60 g, 14%). Synthesis of 1-6: Under a nitrogen atmosphere, 1-5 (12.08 g, 24 mmol) was added to 2-MeTHF (20 mL) containing Mg scrap, and the mixture was heated slowly. Once the solution became turbid, the heating was stopped and the mixture was cooled. The reaction proceeded slowly throughout to obtain 1-6 (1.2 M). Synthesis of Compound 1: Under a nitrogen atmosphere, n-BuLi (1.6 M, 1.83 mL) was slowly added dropwise to a dry t-BuPh solution (50 mL) containing 1-3 (2.12 g, 5.86 mmol), and the reaction was carried out at 0 °C for 2 h. Boron tribromide (BBr3) (2.94 g, 11.72 mmol) was added, and the reaction was carried out at room temperature for 1 h. N,N-diisopropylethylamine (DIEA) (1.23 mL, 7.03 mmol) was added at 0 °C, and the reaction was carried out at 180 °C for 10 h. 1-6 (1.2 M, 10 mL) was added dropwise to the reaction system at room temperature, and after reacting for 2 h, 150 mL of toluene was added. After removing the ether solvent under vacuum, an acidic buffer solution (pH 4.6, 450 mL) was added, and the aqueous phase was washed three times with DCM. The organic solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography (DCM / petroleum ether-1:6). It was recrystallized from DCM and methanol to give compound 1 (0.67 g, 16%), MS: 716.46.

[0022] Synthesis Example 2: Synthesis of Compound 9 ; Synthesis of 9-2: Under a nitrogen atmosphere, 10 mL of THF in LaCl3·2LiCl (0.6 M, 7.33 mL) was kept at -50 °C for 15 min, and then n-BuLi (1.6 M, 2.75 mL) was added dropwise, and the reaction was carried out at -50 °C for 30 min. A solution of 9-1 (0.80 g, 2 mmol) in THF (10 mL) was added dropwise to the above solution, kept at -50 °C for 5 min, and then reacted at 0 °C for 30 min. I2 (5.08 g, 20 mmol) was added, and the reaction was carried out at room temperature for 1 h. The reaction was quenched with water, washed three times with DCM, and the organic solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography (DCM / petroleum ether - 1:5), and recrystallized from dichloromethane and methanol to obtain 9-2 (0.69 g, 70%). Synthesis of 9-3: Under a nitrogen atmosphere, 9-2 (0.64 g, 1.29 mmol), selenium powder (0.41 g, 5.17 mmol), and KOH (0.58 g, 10.34 mmol) were dispersed in DMSO (20 mL) and reacted at 110 °C for 24 h. The reaction was quenched with water, washed three times with DCM, and the organic solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography (DCM / petroleum ether - 1:10), and recrystallized from DCM and methanol to give 9-3 (0.31 g, 76%). The synthesis methods for 9-4 and 1-3 are the same, except that 9-3 replaces 1-2; The synthesis methods for 9-5 and 1-5 are the same, except that 1-3 is replaced by 9-4; The synthesis methods for 9-6 and 1-6 are the same, except that 1-5 is replaced by 9-5; Compound 9 was synthesized using the same method as compound 1, except that 9-7 replaced 1-3 and 9-6 replaced 1-6. MS: 728.29.

[0023] Synthesis Example 3: Synthesis of Compound 17 ; The synthesis methods for 17-1 and 9-3 are the same, except that sulfur powder is used instead of selenium powder. The synthesis methods for 17-2 and 1-3 are the same, except that 17-1 is used instead of 1-2; The synthesis methods for 17-3 and 1-5 are the same, except that 17-2 is used to replace 1-3; Synthesis of 17-4: m-chloroperoxybenzoic acid (mCBPA) (2.32 g, 13.42 mmol) was slowly added to a solution of intermediate 17-3 (0.66 g, 1.34 mmol) in DCM (10 mL), and the mixture was stirred overnight at room temperature. The reaction was quenched with saturated sodium hydroxide solution. The aqueous phase was washed three times with DCM. The organic phases were combined, and the solvent in the organic layer was removed by rotary evaporation. The crude product was purified by silica gel column chromatography (ethyl acetate:DCM-2:1), and recrystallized from DCM and methanol to give 17-4 (0.58 g, 83%). The synthesis methods for 17-5 and 1-6 are the same, except that 17-4 is used to replace 1-5; Compound 17 was synthesized in the same manner as compound 1, except that 9-4 replaced 1-3 and 17-5 replaced 1-6. MS: 776.30.

[0024] Synthesis Example 4: Synthesis of Compound 25 ; The synthesis method of 25-2 is the same as that of 1-5, the difference is that 1-4 is replaced by 25-1; The synthesis method for 25-3 is the same as that for 1-6, except that 1-5 is replaced with 25-2; Compound 25 was synthesized in the same way as compound 1, except that 9-4 replaced 1-3 and 25-3 replaced 1-6. MS: 741.33.

[0025] Synthesis Example 5: Synthesis of Compound 33 ; The synthesis methods for 33-1 and 1-5 are the same, except that 17-2 is used to replace 1-3 and 25-1 is used to replace 1-4. The synthesis method for 33-2 is the same as that for 1-6, except that 1-5 is replaced by 33-1; Compound 33 was synthesized in the same way as compound 1, except that 17-2 replaced 1-3 and 33-2 replaced 1-6. MS: 683.06.

[0026] Synthesis Example 6: Synthesis of Compound 41 ; The synthesis methods for 41-1 and 17-4 are the same, except that 17-3 is replaced with 33-1; The synthesis method of 41-2 is the same as that of 1-6, the difference is that 1-5 is replaced by 41-1; The synthesis method of 41-4 is the same as that of compound 1, except that 41-3 is used to replace 1-3 and 41-2 is used to replace 1-6. Synthesis of 41-5: Under a nitrogen atmosphere, 41-4 (0.7 g, 1 mmol) was dispersed in a mixed solvent of DCM (10 mL), dioxane (5 mL), and water (1 mL). After cooling to 0 °C, DDQ (0.94 g, 4.14 mmol) was slowly added, and the mixture was then allowed to warm naturally to room temperature and stirred overnight. The reaction was quenched with saturated sodium bicarbonate solution, and the aqueous layer was washed three times with DCM. The organic solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography (ethyl acetate / DCM-2:1). Recrystallization from DCM and methanol yielded 41-5 (0.45 g, 63%). Synthesis of compound 41: 41-5 (0.71 g, 1 mmol) and malononitrile (1.32 g, 20 mmol) were dispersed in 10 mL of acetic anhydride and refluxed for 12 h. The organic solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography (ethyl acetate / DCM-2:1). Recrystallization from DCM and methanol gave compound 41 (0.36 g, 48%), MS: 759.37.

[0027] Synthesis Example 7: Synthesis of Compound 49 ; The synthesis methods for 49-1 and 1-5 are the same, except that 9-4 is used to replace 1-3 and 25-1 is used to replace 1-4. The synthesis method of 49-2 is the same as that of 1-6, the difference is that 1-5 is replaced by 49-1; Compound 49 was synthesized in the same way as compound 1, except that 9-7 replaced 1-3 and 49-2 replaced 1-6. MS: 715.28.

[0028] Synthesis Example 8: Synthesis of Compound 55 ; Compound 55 was synthesized in the same way as compound 1, except that 9-4 replaced 1-3 and 41-2 replaced 1-6. MS: 763.26.

[0029] Synthesis Example 9: Synthesis of Compound 61 ; The synthesis methods for 61-2 and 1-5 are the same, except that 17-2 replaces 1-3 and 61-1 replaces 1-4. The synthesis methods for 61-3 and 17-4 are the same, except that 17-3 is replaced with 61-2; The synthesis method of 61-4 is the same as that of 1-6, except that 1-5 is replaced by 61-3; Compound 61 was synthesized in the same way as compound 1, except that 1-6 was replaced by 61-4. MS: 712.38.

[0030] Synthesis Example 10: Synthesis of Compound 67 ; The synthesis method of 67-1 is the same as that of 1-5, the difference is that 1-3 is replaced by 41-3 and 1-4 is replaced by 61-1; The synthesis method of 67-2 is the same as that of 1-6, except that 1-5 is replaced by 67-1; The synthesis method of 67-3 is the same as that of compound 1, except that 9-7 is used to replace 1-3 and 67-2 is used to replace 1-6. The synthesis methods for 67-4 and 41-5 are the same, except that 41-4 is replaced with 67-3; Compound 67 was synthesized in the same way as compound 41, except that 41-5 was replaced by 67-4. MS: 698.35.

[0031] Synthesis Example 11: Synthesis of Compound 73 ; Compound 73 was synthesized in the same way as compound 1, except that 9-4 replaced 1-3 and 61-4 replaced 1-6. MS: 750.26.

[0032] Synthesis Example 12: Synthesis of Compound 79 ; The synthesis method of 79-1 is the same as that of 1-5, the difference is that 1-4 is replaced by 61-1; The synthesis method of 79-2 is the same as that of 1-6, the difference is that 79-1 is used to replace 1-5; Compound 79 was synthesized in the same way as compound 1, except that 17-2 replaced 1-3 and 79-2 replaced 1-6. MS: 680.13.

[0033] Synthesis Example 13: Synthesis of Compound 85 ; The synthesis methods for 85-1 and 1-5 are the same, except that 9-7 replaces 1-3 and 61-1 replaces 1-4. The synthesis methods for 85-2 and 1-6 are the same, except that 1-5 is replaced with 85-1; The synthesis methods for 85-3 and 17-4 are the same, except that 17-2 is used instead of 17-3; Compound 85 was synthesized in the same way as compound 1, except that 1-3 was replaced by 85-3 and 1-6 was replaced by 85-2. MS: 686.31.

[0034] Synthesis Example 14: Synthesis of Compound 93 ; The synthesis methods for 93-2 and 1-5 are the same, except that 1-4 is replaced with 93-1; The synthesis method of 93-3 is the same as that of 1-6, the difference is that 1-5 is replaced by 93-2; Compound 93 was synthesized in the same way as compound 1, except that 9-7 replaced 1-3 and 93-3 replaced 1-6. MS: 712.43.

[0035] Synthesis Example 15: Synthesis of Compound 101 ; The synthesis methods for 101-1 and 1-5 are the same, except that 1-3 is replaced by 9-7 and 1-4 is replaced by 93-1. The synthesis methods for 101-2 and 1-6 are the same, except that 1-5 is replaced by 101-1; Compound 101 was synthesized in the same way as compound 1, except that 85-3 replaced 1-3 and 101-2 replaced 1-6. MS: 734.33.

[0036] Synthesis Example 16: Synthesis of Compound 109 ; The synthesis methods for 109-1 and 1-5 are the same, except that 1-3 is replaced by 41-3 and 1-4 is replaced by 93-1. The synthesis methods for 109-2 and 1-6 are the same, except that 1-5 is replaced by 109-1; The synthesis method of 109-3 is the same as that of compound 1, except that 9-4 is used to replace 1-3 and 109-2 is used to replace 1-6. The synthesis methods for 109-4 and 41-5 are the same, except that 41-4 is replaced with 109-3; Compound 109 was synthesized using the same method as compound 41, except that 41-5 was replaced with 109-4. MS: 810.31.

[0037] Synthesis Example 17: Synthesis of Compound 117 ; The synthesis methods for 117-2 and 1-5 are the same, except that 1-4 is replaced with 117-1; The synthesis method of 117-3 is the same as that of 1-6, except that 1-5 is replaced by 117-2; Compound 117 was synthesized in the same way as compound 1, except that 85-3 replaced 1-3 and 117-3 replaced 1-6. MS: 738.11.

[0038] Synthesis Example 18: Synthesis of Compound 125 ; The synthesis methods for 125-1 and 1-5 are the same, except that 17-2 is used to replace 1-3 and 117-1 is used to replace 1-4. The synthesis methods for 125-2 and 1-6 are the same, except that 1-5 is replaced with 125-2; Compound 125 was synthesized in the same way as compound 1, except that 9-4 replaced 1-3 and 125-2 replaced 1-6. MS: 744.31.

[0039] Example 19: Synthesis of Compound 133 ; Compound 133 was synthesized in the same way as compound 1, except that 1-3 was replaced by 85-3 and 1-6 was replaced by 125-2. MS: 728.30.

[0040] Synthesis Example 20: Synthesis of Compound 139 ; The synthesis methods for 139-2 and 1-5 are the same, except that 1-3 is replaced by 41-3 and 1-4 is replaced by 139-1; The synthesis methods for 139-3 and 1-6 are the same, except that 1-5 is replaced by 139-2; The synthesis method of 139-4 is the same as that of compound 1, except that 1-6 is replaced by 139-3; The synthesis methods for 139-5 and 41-5 are the same, except that 41-4 is replaced by 139-4; Compound 139 was synthesized in the same way as compound 41, except that 41-5 was replaced by 139-5. MS: 737.47.

[0041] Synthesis Example 21: Synthesis of Compound 145 ; The synthesis methods for 145-1 and 1-5 are the same, except that 17-2 is used to replace 1-3 and 139-1 is used to replace 1-4. The synthesis method of 145-2 is the same as that of 1-6, except that 1-5 is replaced by 145-1; Compound 145 was synthesized in the same way as compound 1, except that 17-2 replaced 1-3 and 145-2 replaced 1-6. MS: 683.34.

[0042] Synthesis Example 22: Synthesis of Compound 151 ; The synthesis method of 151-1 is the same as that of compound 1, except that 9-4 is used to replace 1-3 and 139-3 is used to replace 1-6; The synthesis methods for 151-2 and 41-5 are the same, except that 41-4 is replaced by 151-1; Compound 151 was synthesized in the same way as compound 41, except that 41-5 was replaced by 151-2. MS: 775.30.

[0043] Synthesis Example 23: Synthesis of Compound 157 ; The synthesis methods for 157-2 and 1-5 are the same, except that 17-2 is used to replace 1-3 and 157-1 is used to replace 1-4. The synthesis method of 157-3 is the same as that of 1-6, except that 1-5 is replaced by 157-2; Compound 157 was synthesized using the same method as compound 1, except that 1-6 was replaced with 157-2. MS: 680.42.

[0044] Synthesis Example 24: Synthesis of Compound 163 ; The synthesis methods for 163-1 and 1-5 are the same, except that 9-4 is used to replace 1-3 and 157-1 is used to replace 1-4. The synthesis method for 163-2 is the same as that for 1-6, except that 1-5 is replaced by 163-1; Compound 163 was synthesized in the same way as compound 1, except that 9-7 replaced 1-3 and 163-2 replaced 1-6. MS: 702.28.

[0045] Synthesis Example 25: Synthesis of Compound 169 ; The synthesis method of 169-1 is the same as that of 1-5, the difference is that 1-3 is replaced by 41-3 and 1-4 is replaced by 157-1; The synthesis method of 169-2 is the same as that of 1-6, the difference is that 1-5 is replaced by 169-1; The synthesis method of 169-3 is the same as that of compound 1, except that 17-2 replaces 1-3 and 169-2 replaces 1-6. The synthesis methods for 169-4 and 41-5 are the same, except that 41-4 is replaced with 169-3; Compound 169 was synthesized in the same way as compound 41, except that 41-5 was replaced by 169-4. MS: 714.34.

[0046] Synthesis Example 26: Synthesis of Compound 177 ; The synthesis method of 177-1 is the same as that of 1-5, except that 1-4 is replaced by 157-1; The synthesis method of 177-2 is the same as that of 1-6, except that 1-5 is replaced by 177-1; Compound 177 was synthesized in the same way as compound 1, except that 17-2 replaced 1-3 and 177-2 replaced 1-6. MS: 680.37.

[0047] Synthesis Example 27: Synthesis of Compound 185 ; Compound 185 was synthesized using the same method as compound 1, except that 9-4 replaced 1-3 and 157-3 replaced 1-6. MS: 718.71.

[0048] Synthesis Example 28: Synthesis of Compound 193 ; The synthesis methods for 193-2 and 1-5 are the same, except that 1-4 is replaced by 193-1; The synthesis methods for 193-3 and 1-6 are the same, except that 1-5 is replaced by 193-2; Compound 193 was synthesized in the same way as compound 1, except that 9-4 replaced 1-3 and 193-3 replaced 1-6. MS: 776.34.

[0049] Synthesis Example 29: Synthesis of Compound 201 ; The synthesis method of 201-1 is the same as that of 1-5, the difference is that 17-2 is used to replace 1-3 and 193-1 is used to replace 1-4; The synthesis method for 201-2 is the same as that for 1-6, except that 1-5 is replaced by 201-1; Compound 201 was synthesized in the same way as compound 1, except that 17-2 replaced 1-3 and 201-2 replaced 1-6. MS: 718.31.

[0050] Synthesis Example 30: Synthesis of Compound 209 ; The synthesis method of 209-1 is the same as that of 1-5, the difference is that 1-3 is replaced by 41-3 and 1-4 is replaced by 193-1; The synthesis method of 209-2 is the same as that of 1-6, except that 1-5 is replaced by 209-1; The synthesis method of 209-3 is the same as that of compound 1, except that 1-3 is replaced by 85-3 and 1-6 is replaced by 209-2; The synthesis methods for 209-4 and 41-5 are the same, except that 41-4 is replaced with 209-3; Compound 209 was synthesized in the same way as compound 41, except that 41-5 was replaced by 209-4. MS: 794.32.

[0051] In addition, it should be noted that other compounds in this application can be obtained by referring to the preparation methods of the examples listed above, so they will not be listed one by one here.

[0052] Device Examples The device structure is as follows: ITO / HIL(10nm) / HTL(30nm) / EBL(10nm) / EML(Host:Dopant)(30nm) / HBL(10nm) / ETL(30nm) / LiF(0.5nm) / Al(200nm).

[0053] Device fabrication process: The transparent anode electrode ITO substrate was ultrasonically cleaned in isopropanol for 15 minutes and exposed to ultraviolet light for 30 minutes, followed by oxygen plasma treatment for 10 minutes. The treated ITO substrate was then placed in an evaporation equipment, where a 10 nm hole injection layer (HIL), a 30 nm hole transport layer (HTL), a 10 nm electron blocking layer (EBL), a 30 nm light-emitting layer (Host: Dopant) (doping concentration of 1 wt%), a 10 nm hole blocking layer (HBL), and a 30 nm electron transport layer (ETL) were deposited sequentially. Finally, LiF (0.5 nm) and Al were deposited on the electron transport layer as a cathode with a thickness of 200 nm.

[0054] The structures of the compounds used in the above preparation process are as follows: ; Among them, compounds 1, 9, 17, 25, 33, 41, 49, 55, 61, 67, 73, 79, 85, 93, 101, 109, 117, 125, 133, 139, 145, 151, 157, 163, 169, 177, 185, 193, 201, and 209 are present as dopant in the devices of Examples 1 to 30 prepared according to the above device preparation process, and ref-1 is present as dopant in the comparative device prepared according to the above device preparation process; At 10mA / cm 2 The current efficiency (cd / A) of the fabricated device was measured at a current density of 50 mA / cm². 2 The time required for the brightness to decrease to 95% of the initial brightness at a given current density (LT95) was measured. Luminous efficiency was tested using an IVL (current-voltage-luminance) testing system (Suzhou Fosstar Scientific Instruments Co., Ltd.); the lifetime testing system was the OLED lifetime testing system of Suzhou Fosstar Scientific Instruments Co., Ltd., and the results are shown in Table 1 below:

[0055] In the table above, Examples 1-30 show improved current efficiency and lifetime compared to the comparative examples. Compared to the comparative examples, the compounds in this application series contain a dual resonance core. The larger conjugated system can increase the transition dipole moment, accelerate the radiative transition speed, and thus achieve higher efficiency and longer lifetime. In addition, the compounds in this application series have a multi-planar three-dimensional spatial structure, which can simultaneously regulate energy levels and molecular stacking behavior. While suppressing concentration quenching, it maintains intramolecular charge transfer (ICT) and resonance effects in the excited state, exhibiting good film-forming properties and excellent luminescence efficiency.

[0056] The above embodiments only list the effect data of devices made from a portion of the structures. This is a representative sampling test. Based on the experimental data, the overall data is not significantly different and can represent the effects of other unlisted structures.

[0057] Those skilled in the art will readily recognize that many modifications and variations can be made to this invention without departing from its spirit and scope. Therefore, it is contemplated that this invention covers the modifications and variations provided within the scope of the appended claims and their equivalents.

[0058] The applicant declares that the organic electroluminescent material and organic electroluminescent device of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A boron-nitrogen compound, characterized in that, It has the structure shown in general formula I: ； One of X1 and X2 is B and the other is N; one of X3 and X4 is B and the other is N; Y1 and Y2 may be the same or different, and each is independently selected from single bond, CR1R2, O, S, Se, S(=O)2, =C(CN)2; R1 and R2 are each independently selected from C1 to C2. 30 Alkyl or C6~C 30 aryl; Ar is selected from alkyl-substituted C6~C 30 aryl or C3~C 30 Mixed aromatic compounds.

2. The boron-nitrogen compound according to claim 1, characterized in that, X1 is N, and X2 is B.

3. A boron-nitrogen compound according to claim 1, characterized in that, X4 is N, and X3 is B.

4. A boron-nitrogen compound according to claim 2, characterized in that, One of the Y1 is a single bond.

5. A boron-nitrogen compound according to claim 3, characterized in that, One of the Y2 is a single bond.

6. A boron-nitrogen compound according to claim 1, characterized in that, R1 and R2 are each independently selected from C1 to C2. 12 Chain-like alkyl groups.

7. A boron-nitrogen compound according to claim 1, characterized in that, The Ar is phenyl, naphthyl, pyridyl, or pyrimidinyl.

8. A boron-nitrogen compound according to claim 1, characterized in that, The specific structure of this compound is as follows: ； ； ； ； ； ； 。 9. An organic electroluminescent device, comprising a light-emitting layer, characterized in that, The light-emitting layer contains any one of the boron-nitrogen compounds according to claims 1 to 8.

10. The organic electroluminescent device according to claim 9, characterized in that: This organic electroluminescent device is used to manufacture display devices, lighting sources, signal lights, and signs. The display devices include mobile phone displays, computer displays, television displays, smartwatch displays, smart car display panels, and VR or AR helmet displays.

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