Polycyclic-containing bis-boron-nitrogen compound and organic electroluminescent device thereof

Abstract

The application belongs to the technical field of organic electroluminescent materials, and particularly relates to a polycyclic double-boron-nitrogen compound and an organic electroluminescent device thereof. The multiple resonance skeleton of the compound is annelated with a tetramethyl-containing ring to form a three-dimensional structure, which increases the intermolecular distance and prevents the intermolecular close packing, so that the compound can inhibit the fluorescence concentration quenching and the triplet exciton annihilation. Based on the above effects, when the compound is applied in the electroluminescent device, the maximum external quantum efficiency of the device can be improved, and the attenuation of the device efficiency under high brightness caused by the triplet exciton annihilation can be reduced. In addition, the anti-aggregation feature can improve the service life of the device.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent materials technology, specifically relating to a polycyclic diboron nitrogen compound and its organic electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs), as the core technology of third-generation displays, have been widely used in various terminal display products such as smartphones, tablets, OLED TVs, automotive displays, and wearable devices due to their outstanding advantages such as self-emission, wide viewing angle, high color gamut, ultra-thin flexibility, high contrast, and fast response. They also have broad application prospects in fields such as solid-state lighting and optoelectronic devices. The key performance characteristics of OLED devices (including luminous efficiency, color purity, lifespan, and power consumption) are directly determined by the molecular structure design of their emissive layer material. Therefore, the research and development of emissive layer materials is a core element in the iterative upgrading and industrialization of OLED technology.

[0003] OLED light-emitting materials have undergone three generations of evolution. Traditional fluorescent materials have low exciton utilization, phosphorescent materials suffer from efficiency roll-off, dependence on precious metals, and core technology monopoly issues, while traditional donor-acceptor (DA) type thermally activated delayed fluorescence (TADF) materials have insufficient color purity, making it difficult to meet the requirements of the BT.2020 ultra-high definition standard.

[0004] Multiple resonance TADF (MR-TADF) materials, constructed with a rigid fused-ring framework of boron / nitrogen heteroatoms, can achieve narrow-spectrum emission and high-efficiency luminescence, meeting the demands of ultra-high-definition displays. However, existing MR-TADF materials still face key technological bottlenecks. Their molecular framework has a highly rigid planar structure, which easily leads to strong π-π interactions between molecules, causing aggregation effects that result in fluorescence quenching and exciton annihilation. Aggregation effects not only reduce the maximum external quantum efficiency of OLED devices but also cause severe efficiency degradation under high-brightness operating conditions. Furthermore, molecular aggregation leads to non-uniform film morphology in the light-emitting layer, reducing the device's lifespan and severely restricting its commercial application.

[0005] Therefore, how to overcome the molecular aggregation problem of existing MR-TADF materials and develop MR-TADF luminescent materials suitable for commercial applications has become a technical problem that urgently needs to be solved in the current OLED technology field, and it is also the starting point of this invention. Summary of the Invention

[0006] To address the problems existing in the background art, the present invention provides a polycyclic diboron nitrogen compound, the structure of which is shown in general formula (1): ; Rings A, B, C, and D are each independently selected from substituted or unsubstituted unsaturated carbon rings having 6-30 carbon atoms, wherein at least one ring is selected from... * indicates a connection point; X1 is selected from O, S, Se, BR1, NR1, CR2R3; X2 exists or does not exist. When it exists, X2 is selected from single bond, O, S, Se, BR1, NR1, CR2R3; R is independently selected from hydrogen, deuterium, cyano, trifluoromethyl, deuterated or undeuterated C1-C atoms. 10 Alkyl, substituted or unsubstituted C6-C 12 Aryl or C5-C 12 The heteroaryl group has heteroatoms of N, O, S, or Se, and n is from 1 to the largest number of substitution sites in the ring; R1 is independently selected from substituted or unsubstituted phenyl groups; R2 and R3 are each independently selected from deuterated or undeuterated C1-C4 alkyl, substituted or unsubstituted phenyl groups, and R2 and R3 can be linked together to form a ring; Indicates whether a key relationship exists or not; When substitutions are present, the substituents are each independently selected from deuterium, cyano, trifluoromethyl, deuterated or undeuterated methyl, deuterated or undeuterated isopropyl, deuterated or undeuterated tert-butyl, deuterated or undeuterated phenyl.

[0007] Preferably, rings A, B, C, and D are each independently selected from substituted or unsubstituted unsaturated carbon rings having 6-12 carbon atoms, wherein at least one ring is selected from... .

[0008] As a preferred embodiment of the present invention, R is independently selected from hydrogen atom, deuterium atom, cyano group, trifluoromethyl group, deuterated or undeuterated C group. 1- C4 alkyl, substituted or unsubstituted phenyl.

[0009] More preferably, the polycyclic diboron nitrogen compound of the present invention is selected from any one of the following chemical structures: ; ; ; ; ; ; ; ; ; ; ; ; ; .

[0010] A second aspect of the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising a cathode layer, an anode layer and an organic functional layer therebetween; the organic functional layer comprising a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer, wherein the light-emitting layer contains at least one of the polycyclic diboron nitrogen compounds described in the present invention.

[0011] Preferably, the light-emitting layer comprises a host material and a guest material, wherein the guest material comprises at least one of the polycyclic diboron nitrogen compounds.

[0012] Preferably, the organic electroluminescent device is used to manufacture display devices, lighting sources, signal lights, and signs, wherein the display devices include mobile phone displays, computer displays, television displays, smartwatch displays, smart car display panels, and VR or AR helmet displays.

[0013] The above lists some specific structural forms of the high-efficiency narrow-band electroluminescent materials described in this invention. However, this invention is not limited to these chemical structures. Any structure based on the structure shown in general formula (1), in which ring A, ring B, ring C, ring D, X1, X2, R1, R2, R3 and R satisfy the above-mentioned limiting conditions should be included.

[0014] The beneficial effects of this invention are as follows: This invention provides polycyclic diboron nitrogen compounds and their organic electroluminescent devices. The multiple resonance framework of these compounds forms a three-dimensional structure with the tetramethyl-containing ring, increasing intermolecular distance and preventing close-packing. Therefore, they can suppress fluorescence quenching and triplet exciton annihilation. Based on these effects, when applied in electroluminescent devices, these materials help improve the maximum external quantum efficiency of the device while reducing the efficiency degradation at high brightness caused by triplet exciton annihilation. Furthermore, the anti-aggregation characteristics can extend the device's lifespan. Detailed Implementation

[0015] Before providing a detailed description of the invention, it should be understood that the terminology used in this specification is for describing specific embodiments only and is not intended to limit the scope of the invention. The scope of the invention should be defined only by the scope of the appended claims. Unless otherwise expressly stated, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art.

[0016] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the protection scope of the present invention.

[0017] Synthesis Examples The present invention does not impose any particular restrictions on the source of the raw materials used in the following embodiments, which can be commercially available products or prepared by methods known to those skilled in the art.

[0018] Example 1: Synthesis of Compound 1 ; Synthesis of 1-3: Under a nitrogen atmosphere, 1-1 (1.67 g, 10.0 mmol), 1-2 (3.24 g, 10.0 mmol), tris(dibenzylacetone)dipalladium (Pd2(dba)3) (175 mg, 0.2 mmol), 2-biscyclohexylphosphine-2',4',6'-triisopropylbiphenyl (X-phos) (114 mg, 0.25 mmol), and sodium tert-butoxide (1.06 g, 11.0 mmol) were added to 60 mL of toluene. The reaction mixture was heated to 110 °C and stirred for 6 hours. After the reaction was complete, the reaction mixture was cooled to room temperature. Add 50 mL of deionized water to the reaction system, collect the organic phase by separation, dry with anhydrous sodium sulfate, remove the solvent of the organic layer by rotary evaporation, purify the crude product by column chromatography, and recrystallize to obtain 1-3 (3.61 g, 88%), with a molecular weight determined by mass spectrometry of 410.38 (theoretical value: 410.54). Synthesis of 1-4: Under a nitrogen atmosphere, 1-3 (3.28 g, 8.0 mmol) was dissolved in 80 mL of tetrahydrofuran solution, and NaH (0.21 g, 8.8 mmol) was slowly added. After reacting at room temperature for 10 minutes, di-tert-butyl dicarbonate (Boc2O) (1.93 g, 9.6 mmol) was added, and the mixture was refluxed for 6 h. After the reaction was complete, tetrahydrofuran was removed by rotary evaporation, and the mixture was extracted with dichloromethane and water. The organic phase was concentrated, purified by column chromatography, and recrystallized to obtain 1-4 (2.94 g, 72%). The molecular weight determined by mass spectrometry was 510.51 (theoretical value: 510.65). Synthesis of 1-6: Under a nitrogen atmosphere, 1-4 (2.55 g, 5.0 mmol), 1-5 (1.12 g, 5.5 mmol), and potassium tert-butoxide (1.12 g, 10.0 mmol) were added to 50 mL of DMF. The reaction system was heated to 120 °C and stirred for 12 h. After the reaction was complete, the reaction mixture was cooled to room temperature. 50 mL of deionized water was added to the reaction system, and the mixture was extracted with dichloromethane and water. The organic phase was concentrated, purified by column chromatography, and recrystallized to obtain 1-6 (2.95 g, 85%). The molecular weight determined by mass spectrometry was 694.82 (theoretical value: 694.96). Synthesis of 1-7: Under a nitrogen atmosphere, 1-6 (3.47 g; 5.0 mmol) was dissolved in 40 mL of tetrahydrofuran, and trifluoroacetic acid (1.0 mL; 13.6 mmol) was added dropwise at room temperature while stirring continuously for 6 h. After the reaction was complete, the tetrahydrofuran was removed by rotary evaporation, and the solid was poured into a saturated sodium bicarbonate solution. The solid precipitated, filtered, and the filter cake was washed with methanol to obtain 1-7 (2.56 g, 86%). The molecular weight determined by mass spectrometry was 594.70 (theoretical value: 594.84). The synthesis methods for 1-9 and 1-3 are the same, the difference being that 1-7 replaces 1-1 and 1-8 replaces 1-2. The molecular mass determined by mass spectrometry analysis is 795.79 (theoretical value: 795.93). Synthesis of Compound 1: 1-9 (3.98 g, 5.0 mmol) was dissolved in 150 mL of tert-butylbenzene under a nitrogen atmosphere. t In a nitrogen atmosphere at 0°C, tert-butyllithium (-BuPh) was slowly added. t7.5 mL of a pentane solution of -BuLi (1.6 M) was stirred at 60 °C for 2 h. Boron tribromide (BBr3) (3.01 g, 12.0 mmol) was added, and the reaction mixture was stirred at room temperature for 1 h. N,N-diisopropylethylamine (DIEA) (4.63 g, 36.0 mmol) was added, and the mixture was reacted at room temperature for 1 h. Then, the mixture was heated to 130 °C and stirred for 6 h. The reaction mixture was then cooled to room temperature, and methanol was added to remove residual boron tribromide. The mixture was separated, extracted with water and dichloromethane, and the organic phase was collected by liquid-liquid extraction. After drying with anhydrous sodium sulfate, the solvent in the organic layer was removed by rotary evaporation. The crude product was purified by column chromatography and recrystallized to give compound 1 (1.23 g, 33%). The molecular weight determined by mass spectrometry was 742.51 (theoretical value: 742.62).

[0019] Example 2: Synthesis of Compound 13 ; Synthesis of 13-3: Under a nitrogen atmosphere, 13-1 (2.79 g, 10.0 mmol), 13-2 (3.10 g, 10.0 mmol), and cesium carbonate (8.20 g, 250 mmol) were added to 100 mL of DMF and reacted overnight at 120 °C. Heating was stopped, and after cooling to room temperature, 150 mL of water was added and stirred for 10 min. A large amount of solid precipitated out. The solid was filtered, and the filter cake was washed with ethanol for 2 h. After cooling, the solid was filtered again to obtain 13-3 (4.27 g, 75%). The molecular weight determined by mass spectrometry was 569.29 (theoretical value: 569.43). The synthesis methods for 13-5 and 1-3 are the same, except that 1-1 is replaced by 13-4 and 1-2 is replaced by 13-3. The molecular mass determined by mass spectrometry is 637.63 (theoretical value: 637.75). The synthesis method of 13-6 is the same as that of 1-6, except that 1-4 is replaced by 13-2. The molecular mass determined by mass spectrometry is 494.40 (theoretical value: 494.31). The synthesis methods for 13-7 and 1-3 are the same, except that 1-1 is replaced by 13-5 and 1-2 is replaced by 13-6. The molecular mass determined by mass spectrometry is 1051.09 (theoretical value: 1051.15). Compound 13 was synthesized using the same method as compound 1, except that 1-9 was replaced with 13-7. The molecular mass determined by mass spectrometry was 908.78 (theoretical value: 908.93).

[0020] Example 3: Synthesis of Compound 23 ; The synthesis methods of 23-3 and 13-3 are the same, except that 23-1 is used to replace 13-1 and 23-2 is used to replace 13-2. The molecular mass determined by mass spectrometry is 605.73 (theoretical value: 605.88). The synthesis methods for 23-5 and 1-3 are the same, except that 23-4 replaces 1-1 and 23-3 replaces 1-2. The molecular mass determined by mass spectrometry is 694.17 (theoretical value: 694.20). The synthesis methods of 23-6 and 1-3 are the same, except that 23-5 replaces 1-1 and 13-6 replaces 1-2. The molecular mass determined by mass spectrometry is 1107.48 (theoretical value: 1107.60). The synthesis method of compound 23-7 is the same as that of compound 1, except that 1-9 is replaced by 23-6. The molecular mass determined by mass spectrometry is 965.24 (theoretical value: 965.38). Synthesis of Compound 23: Under a nitrogen atmosphere, 23-7 (2.90 g, 3.0 mmol), 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride (IPrHCl) (53 mg, 0.12 mmol), palladium(II) acetate (13.6 mg, 0.06 mmol), and potassium carbonate (0.83 g, 4.2 mmol) were added to 40 mL of N,N-dimethylacetamide (DMAc). The reaction mixture was heated to 160 °C and stirred for 8 h. After the reaction was complete, the reaction mixture was cooled to room temperature. The precipitated solid was collected by filtration, washed with acetone, and the crude product was purified by column chromatography. Recrystallization yielded compound 23 (1.73 g, 62%), with a molecular weight determined by mass spectrometry of 928.77 (theoretical value: 928.92).

[0021] Example 4: Synthesis of Compound 36 ; The synthesis methods of 36-5 and 23-7 are the same, except that 13-1 is used to replace 23-1, 36-1 is used to replace 23-2, and 13-4 is used to replace 23-4. The other steps are the same. The molecular mass determined by mass spectrometry analysis is 887.11 (theoretical value: 887.26). Synthesis of compound 36: Under a nitrogen atmosphere, 36-5 (4.44 g, 5.0 mmol), carbazole (0.92 g, 5.5 mmol), Pd(dba)2 (55 mg, 0.1 mmol), a 10% (w / w) toluene solution of tri-tert-butylphosphine (0.40 g, 0.2 mol of tri-tert-butylphosphine), and sodium tert-butoxide (1.45 g, 15 mmol) were added to 80 mL of dry toluene and reacted overnight at 120 °C. Heating was stopped, and after cooling to room temperature, 30 mL of water was added and stirred for 10 min. A large amount of solid precipitated out. The solid was filtered, and the filter cake was washed with ethanol for 1 h. After cooling and filtration, the crude product was purified by column chromatography and recrystallized to obtain compound 36 (3.59 g, 78%). The molecular weight determined by mass spectrometry was 928.77 (theoretical value: 919.83).

[0022] Example 5: Synthesis of Compound 43 ; Compound 43 was synthesized in the same way as 23-7, except that 23-1 was replaced by 43-1, 23-2 was replaced by 13-2, and 23-4 was replaced by 13-4. The other steps were the same. The molecular mass determined by mass spectrometry was 924.76 (theoretical value: 924.93).

[0023] Example 6: Synthesis of Compound 63 ; Synthesis of 63-3: Under a nitrogen atmosphere, 63-2 (1.6 M, 6.3 mL) was slowly added dropwise to a solution of 63-1 (2.92 g, 10.0 mmol) in 50 mL of dry xylene. The reaction was carried out at -78 °C for 2 h, then naturally warmed to room temperature and stirred overnight. The reaction was quenched with water, and the aqueous phase was washed three times with DCM. The organic phases were combined, evaporated to dryness, and the crude product was purified by column chromatography. Recrystallization with THF and MeOH yielded 63-3 (3.32 g, 73%). The mass spectrometry analysis determined the fraction to be 454.57 (theoretical value: 454.70). Compound 63 was synthesized using the same method as 23-7, except that 23-1 was replaced by 63-3, 23-2 by 13-2, and 23-4 by 13-4. The other steps were the same. The molecular mass determined by mass spectrometry was 1084.10 (theoretical value: 1084.20).

[0024] Example 7: Synthesis of Compound 69 ; The synthesis methods of 69-2 and 1-3 are the same, except that 1-1 is replaced by 13-4 and 1-2 is replaced by 69-1. The molecular mass determined by mass spectrometry is 360.19 (theoretical value: 360.34). Synthesis of 69-3: Under a nitrogen atmosphere, n -BuLi (1.6 M, 2.5 mL) was slowly added dropwise to a dry t-BuPh (50 mL) solution of 69-2 (1.44 g, 4.0 mmol), and the reaction was carried out at 0 °C for 2 h. Then, a t-BuPh (20 mL) solution of 9-fluorenone (720 mg, 4.0 mmol) was slowly added dropwise, and the mixture was allowed to cool naturally to room temperature. The reaction was quenched with H₂O, and the organic solvent was removed by rotary evaporation. The crude product was purified by column chromatography and recrystallized with THF and MeOH to obtain an intermediate. HCl (3.7 mL) was slowly added dropwise to a CH₃COOH (37.0 mL) solution of the intermediate. After stirring under a nitrogen atmosphere for 10 min, the mixture was rapidly vacuum filtered to obtain a filter cake, washed with MeOH, and then recrystallized with THF and MeOH to obtain 69-3 (1.33 g, 75%). The molecular weight determined by mass spectrometry was 443.48 (theoretical value: 443.63). The synthesis methods for 69-7 and 13-5 are the same, except that 13-1 is replaced by 69-3, 13-2 is replaced by 69-4, and 13-4 is replaced by 69-6. The other steps are the same. The molecular mass determined by mass spectrometry is 765.71 (theoretical value: 765.84). Compound 69 was synthesized using the same method as compound 13, except that 13-2 was replaced with 69-4 and 13-5 was replaced with 69-7. The other steps were the same. The molecular mass determined by mass spectrometry was 1056.88 (theoretical value: 1057.01).

[0025] Example 8: Synthesis of Compound 73 ; The synthesis methods of 73-3 and 13-5 are the same, except that 73-1 is used instead of 13-1. The other steps are the same. The molecular mass determined by mass spectrometry analysis is 639.61 (theoretical value: 639.77). Compound 73 was synthesized using the same method as compound 13, except that 1-5 was replaced by 73-4 and 13-5 was replaced by 73-3. The other steps were the same. The molecular mass determined by mass spectrometry was 926.89 (theoretical value: 927.01).

[0026] Example 9: Synthesis of Compound 108 ; The synthesis method of 108-3 is the same as that of 1-3, the difference being that 1-1 is replaced by 108-1 and 1-2 is replaced by 108-2. The molecular mass determined by mass spectrometry analysis is 307.33 (theoretical value: 307.48). The synthesis methods of 108-4 and 13-3 are the same, the difference being that 108-3 replaces 13-1 and 108-2 replaces 13-2. The molecular mass determined by mass spectrometry is 597.34 (theoretical value: 597.48). Compound 108 was synthesized using the same method as compound 13, except that 108-4 was used instead of 13-6. The other steps were the same. The molecular mass determined by mass spectrometry was 1012.22 (theoretical value: 1012.10).

[0027] Example 10: Synthesis of Compound 122 ; Compound 122 was synthesized using the same method as compound 13, except that 108-4 was used to replace 13-6 and 63-5 was used to replace 13-5. The other steps were the same. The molecular mass determined by mass spectrometry was 1187.25 (theoretical value: 1187.37).

[0028] Example 11: Synthesis of Compound 125 ; Compound 125 was synthesized using the same method as compound 13, except that 1-5 was replaced with 125-1 and 13-5 was replaced with 73-4. The other steps were the same. The molecular mass determined by mass spectrometry was 896.77 (theoretical value: 896.92).

[0029] Example 12: Synthesis of Compound 132 ; The synthesis method of compound 132-4 is the same as that of compound 1, except that 1-5 is replaced by 125-1. The other steps are the same. The molecular mass determined by mass spectrometry is 728.43 (theoretical value: 728.59). Synthesis of compound 132: Under a nitrogen atmosphere, 132-4 (3.64 g, 5.0 mmol), 25 mL of heavy water, and 10 mL of toluene were added to a 100 mL three-necked flask and stirred at 120 °C for 24 h. After cooling the reaction system to room temperature, it was extracted three times with dichloromethane and water. After separation, the organic phase was used to remove the solvent using a rotary evaporator to obtain the crude product. The crude product was purified by column chromatography to obtain compound 132 (3.04 g, 78%), with a molecular weight determined by mass spectrometry of 778.77 (theoretical value: 778.90).

[0030] Example 13: Synthesis of Compound 137 ; The synthesis methods of 137-3 and 13-5 are the same, except that 137-1 is used instead of 13-2. The other steps are the same. The molecular mass determined by mass spectrometry analysis is 595.53 (theoretical value: 595.67). Compound 137 was synthesized in the same way as compound 13, except that 137-1 replaced 13-2, 125-1 replaced 1-5, and 137-3 replaced 13-5. The other steps were the same. The molecular mass determined by mass spectrometry was 810.61 (theoretical value: 810.74).

[0031] Example 14: Synthesis of Compound 147 ; Compound 147 was synthesized using the same method as compound 13, except that 125-2 was used to replace 13-6 and 63-5 was used to replace 13-5. The other steps were the same. The molecular mass determined by mass spectrometry was 1070.06 (theoretical value: 1070.18).

[0032] Example 15: Synthesis of Compound 176 ; ; The synthesis methods of 176-2 and 13-5 are the same, except that 13-2 is replaced by 69-4 and 13-4 is replaced by 69-6. The other steps are the same. The molecular mass determined by mass spectrometry analysis is 601.49 (theoretical value: 601.63). The synthesis methods of 176-4 and 1-3 are the same, except that 1-1 is replaced by 176-3 and 1-2 is replaced by 108-2. The molecular mass determined by mass spectrometry is 293.31 (theoretical value: 293.45). The synthesis methods of 176-5 and 13-3 are the same, the difference being that 13-1 is replaced by 176-4 and 13-2 is replaced by 69-4. The molecular mass determined by mass spectrometry is 603.28 (theoretical value: 603.44). Compound 176 was synthesized using the same method as compound 13, except that 13-6 was replaced with 176-5 and 13-5 was replaced with 176-2. The other steps were the same. The molecular mass determined by mass spectrometry was 981.79 (theoretical value: 981.94).

[0033] Example 16: Synthesis of Compound 195 ; The synthesis methods of 195-2 and 1-3 are the same, the difference being that 1-1 is replaced by 108-1 and 1-2 is replaced by 195-1. The molecular mass determined by mass spectrometry analysis is 335.41 (theoretical value: 335.54). The synthesis methods of 195-4 and 13-5 are the same, except that 13-1 is replaced by 195-1. The other steps are the same. The molecular mass determined by mass spectrometry is 693.70 (theoretical value: 693.86). The synthesis methods of 195-6 and 13-6 are the same, except that 13-5 is replaced by 195-5. The molecular mass determined by mass spectrometry is 440.09 (theoretical value: 440.22). Compound 195 was synthesized using the same method as compound 13, except that 13-6 was replaced with 195-6 and 13-5 was replaced with 195-4. The other steps were the same. The molecular mass determined by mass spectrometry was 910.79 (theoretical value: 910.95).

[0034] Example 17: Synthesis of Compound 203 ; The synthesis methods of 203-3 and 13-5 are the same, except that 13-1 is replaced by 203-1. The other steps are the same. The molecular mass determined by mass spectrometry is 691.72 (theoretical value: 691.84). The synthesis methods for 203-4 and 13-7 are the same, except that 13-6 is replaced by 195-6 and 13-5 is replaced by 203-3. The other steps are the same. The molecular mass determined by mass spectrometry analysis is 1051.03 (theoretical value: 1051.15). Synthesis of compound 203: 203-4 (5.26 g, 5.0 mmol) was dissolved in 150 mL of tert-butylbenzene under a nitrogen atmosphere. tIn a nitrogen atmosphere at 0°C, 7.5 mL of a pentane solution of tert-butyllithium (t-BuLi) (1.6 M) was slowly added, and the mixture was stirred at 60°C for 2 h. Boron tribromide (BBr3) (3.01 g, 12.0 mmol) was then added, and the reaction mixture was stirred at room temperature for 1 h. N,N-diisopropylethylamine (DIEA) (4.63 g, 36.0 mmol) was then added, and the mixture was reacted at room temperature for 1 h. The mixture was then heated to 130°C and stirred for 6 h. The reaction mixture was then cooled to room temperature, and methanol was added to remove residual boron tribromide. The mixture was separated, extracted with water and dichloromethane, and the organic phase was collected by liquid-liquid extraction. After drying with anhydrous sodium sulfate, the solvent in the organic layer was removed by rotary evaporation. The crude product was separated by column chromatography, and recrystallized to give compound 203 (0.59 g, 13%). The molecular weight determined by mass spectrometry was 908.80 (theoretical value: 908.93).

[0035] Example 18: Synthesis of Compound 211 ; Compound 211 was synthesized in the same way as compound 13, except that 211-1 replaced 13-1, 211-4 replaced 1-5, and 211-3 replaced 13-5. The other steps were the same. The molecular mass determined by mass spectrometry was 940.83 (theoretical value: 940.99).

[0036] Example 19: Synthesis of Compound 220 ; Compound 220 was synthesized using the same method as compound 13, except that 1-5 were replaced with 220-1. The other steps were the same. The molecular mass determined by mass spectrometry was 908.82 (theoretical value: 908.93).

[0037] Example 20: Synthesis of Compound 239 ; The synthesis methods for 239-2 and 1-3 are the same, except that 239-1 is used to replace 1-1 and 108-2 is used to replace 1-2. The molecular mass determined by mass spectrometry is 307.35 (theoretical value: 307.48). The synthesis methods of 239-3 and 13-3 are the same, except that 13-1 is replaced by 239-2. The molecular mass determined by mass spectrometry is 597.36 (theoretical value: 597.48). Compound 239 was synthesized using the same method as compound 13, except that 239-3 replaced 13-6 and 43-3 replaced 13-5. The other steps were the same. The molecular mass determined by mass spectrometry was 1028.22 (theoretical value: 1028.10).

[0038] Example 21: Synthesis of Compound 258 ; The synthesis methods of 258-3 and 13-5 are the same, except that 258-1 is used instead of 13-1. The other steps are the same. The molecular mass determined by mass spectrometry is 691.68 (theoretical value: 691.84). Compound 258 was synthesized using the same method as compound 13, except that 195-6 was used instead of 13-6 and 258-3 was used instead of 13-5. The other steps were the same. The molecular mass determined by mass spectrometry was 908.80 (theoretical value: 908.93).

[0039] Example 22: Synthesis of Compound 263 ; Compound 263 was synthesized using the same method as compound 13, except that 13-5 was replaced with 203-3. The other steps were the same. The molecular mass determined by mass spectrometry was 962.87 (theoretical value: 963.02).

[0040] Example 23: Synthesis of Compound 285 ; The synthesis methods of 285-3 and 13-5 are the same, except that 285-1 is used instead of 13-1. The other steps are the same. The molecular mass determined by mass spectrometry is 677.71 (theoretical value: 677.82). The synthesis methods for 285-4 and 13-7 are the same, except that 13-6 is replaced by 195-6 and 13-5 is replaced by 285-3. The other steps are the same. The molecular mass determined by mass spectrometry is 1036.97 (theoretical value: 1037.12). Compound 285 was synthesized using the same method as compound 203, except that 203-4 was replaced with 285-4. Compound 285 was isolated and its molecular mass, determined by mass spectrometry, was 894.75 (theoretical value: 894.90).

[0041] Example 24: Synthesis of Compound 298 ; The synthesis methods of 298-2 and 13-3 are the same, except that 298-1 is used instead of 13-1. The molecular mass determined by mass spectrometry is 641.42 (theoretical value: 641.55). Compound 298 was synthesized using the same method as compound 13, except that 73-4 replaced 13-5 and 298-2 replaced 13-6. The other steps were the same. The molecular mass determined by mass spectrometry was 1058.03 (theoretical value: 1058.18).

[0042] Example 25: Synthesis of Compound 320 ; The synthesis methods of 320-2 and 1-3 are the same, except that 320-1 is used to replace 1-1 and 108-2 is used to replace 1-2. The molecular mass determined by mass spectrometry is 293.31 (theoretical value: 293.45). The synthesis methods of 320-3 and 13-3 are the same, except that 13-1 is replaced by 239-2. The molecular mass determined by mass spectrometry is 583.33 (theoretical value: 583.45). Compound 320 was synthesized using the same method as compound 13, except that 13-6 was replaced with 320-3. The other steps were the same. The molecular mass determined by mass spectrometry was 997.95 (theoretical value: 998.07).

[0043] Other compounds for which specific synthesis steps are not listed can be prepared using common knowledge in the art, in conjunction with the above examples.

[0044] Device Examples This invention also provides an organic electroluminescent device. The following embodiment uses an OLED organic light-emitting device as an example for illustration; however, it should be understood that the following detailed description is not intended to limit the invention, and those skilled in the art can extend the application of the following detailed description to other organic light-emitting devices.

[0045] In a specific embodiment, a hole injection layer is formed on the anode layer, a hole transport layer is formed on the hole injection layer, an electron injection layer is formed on the electron transport layer, a cathode layer is formed on the electron injection layer, and a light-emitting layer is located between the hole transport layer and the electron transport layer.

[0046] Glass or polymer materials can be used as the substrate beneath the anode layer. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays.

[0047] The anode layer material can be selected from transparent conductive oxide materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), and zinc oxide (ZnO), and any combination thereof. The cathode layer material can be metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag), and any combination thereof.

[0048] The hole injection layer can be selected from metalloporphyrins, oligothiophenes, arylamines, hexanitrile hexaazabenzophenanthrenes, etc., but is not limited to these.

[0049] The hole transport layer can be selected from materials such as diphenylamine compounds, fluorene compounds, carbazole compounds, and aromatic amine derivatives, but is not limited to these.

[0050] The luminescent layer material typically contains a guest material and a host material, wherein the guest material is at least one of the polycyclic boron nitrogen compounds represented by the general formula (1) of this invention.

[0051] The electron transport layer can be selected from materials such as quinolines, imidazoles, o-phenanthroline compounds, triazoles, metal chelates, azabenzene derivatives, diazanthracene derivatives, silicon-containing heterocyclic compounds, boron-containing heterocyclic compounds, cyano compounds, and benzimidazoles, but is not limited to these.

[0052] The electron injection layer material can be selected from Li, Ca, Sr, LiF, CsF, CaF2, BaO, Li2CO3, CaCO3, Li2C2O4, Cs2C2O4, CsAlF4, LiOx, Yb, Tb, cesium 8-hydroxyquinoline, tris(8-hydroxyquinoline)aluminum, etc., but is not limited to these.

[0053] The cathode material may be selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, including their compounds or mixtures thereof (e.g., a mixture of Ag and Mg), but is not limited thereto.

[0054] The organic functional layer of the aforementioned organic electroluminescent device can be deposited by vacuum deposition, spin coating, casting, etc. When using vacuum deposition, the conditions for vacuum deposition vary depending on the compound.

[0055] To evaluate the luminescence performance of the polycyclic boron-nitrogen compounds of the present invention in organic electroluminescent devices, this application also provides some representative examples of electroluminescent devices. However, it should be noted that the following detailed description is not intended to limit the invention, and those skilled in the art can extend the application of the following detailed description to other organic electroluminescent devices.

[0056] An electroluminescent device with the structure [ITO / HATCN (6nm) / TAPC (50nm) / EML (20nm) / TmPyPb (60nm) / LiF (1nm) / Al (100nm)]; Its preparation method includes the following steps: (1) Substrate treatment: Transparent ITO glass was used as the substrate for preparing electroluminescent devices. It was first ultrasonically treated with 5% ITO washing solution for 30 min, and then ultrasonically washed with distilled water (2 times), acetone (2 times), and isopropanol (2 times) in sequence. It was baked in a clean environment until the solvent was completely removed, cleaned with ultraviolet light and ozone, and bombarded with low-energy cation beam.

[0057] (2) The device is fabricated using a vacuum deposition equipment with a vacuum evaporation process. The glass substrate is placed in the vacuum chamber of the evaporation equipment. When the vacuum degree of the vacuum evaporation system reaches 5×10 -4 Vapor deposition begins when the pressure is below Pa, and various organic layers, LiF electron injection layers, and metal Al electrodes are sequentially deposited on ITO glass using a vacuum evaporation process.

[0058] HATCN is used as the hole injection layer, TAPC is used as the hole transport layer, EML represents the light-emitting layer, the light-emitting layer is based on 2,6-DCzPPy, and the polycyclic boron nitrogen compound prepared in this invention is used as the guest material (doping material) with a doping weight percentage of 10%. TmPyPb is used as the electron transport layer, and LIF is used as the electron injection layer.

[0059] Preparation of Examples 1-25: When forming the light-emitting layer, the corresponding compounds in Table 1 were used as guest materials, and the devices of the examples were prepared using the above preparation method.

[0060] Preparation of Comparative Examples 1-3: When forming the light-emitting layer, the corresponding compounds in Table 1 were used as guest materials, and comparative devices were prepared using the above preparation method.

[0061] The structures of the compounds used in the above preparation process are as follows: .

[0062] At 1 cd / m 2 The maximum external quantum efficiency (EQE) of the fabricated device was measured at a brightness of 1000 cd / m². 2 The efficiency roll-off (attenuation) percentage of the device was measured at a brightness of 50 mA / cm². 2The time required for the brightness to decrease to 95% of the initial brightness at a given current density (device lifetime LT95) was measured. External quantum efficiency, efficiency roll-off, and lifetime are all relative values ​​(based on Comparative Example 1). Detailed data are shown in Table 1. ; As can be seen from Table 1 above, compared with Comparative Examples 2 and 3, the series of compounds of the present invention have significantly enhanced the intramolecular charge transfer effect through the synergistic effect of the double BN donor-acceptor units to construct a long conjugated framework, effectively regulating the energy level structure of the molecule, achieving excellent bipolar carrier transport performance, and significantly improving the efficiency and lifespan of the device. Compared with Comparative Example 1, the present invention, through structural design, introduces a tetramethyl-containing cyclic compound as a light-emitting guest on the basis of a strong and rigid conjugated framework. Under high concentration doping, the device prepared exhibits the advantages of high efficiency light emission and long service life.

[0063] 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.

[0064] Those skilled in the art will readily recognize that many modifications and variations can be made to the invention without departing from its spirit and scope. Therefore, it is contemplated that the invention covers the modifications and variations provided within the scope of the appended claims and their equivalents.

[0065] 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 polycyclic diboron nitrogen compound, characterized in that, Its structure is shown in general formula (1): ； Rings A, B, C, and D are each independently selected from substituted or unsubstituted unsaturated carbon rings having 6-30 carbon atoms, wherein at least one ring is selected from... or * indicates a connection point; X1 is selected from O, S, Se, BR1, NR1, CR2R3; X2 exists or does not exist. When it exists, X2 is selected from single bond, O, S, Se, BR1, NR1, CR2R3; R is independently selected from hydrogen, deuterium, cyano, trifluoromethyl, deuterated or undeuterated C1-C atoms. 10 Alkyl, substituted or unsubstituted C6-C 12 Aryl or C5-C 12 The heteroaryl group has heteroatoms of N, O, S, or Se, and n is from 1 to the largest number of substitution sites in the ring; R1 is independently selected from substituted or unsubstituted phenyl groups; R2 and R3 are each independently selected from deuterated or undeuterated C1-C4 alkyl, substituted or unsubstituted phenyl groups, and R2 and R3 can be linked together to form a ring; Indicates whether a key relationship exists or not; When substitutions are present, the substituents are each independently selected from deuterium, cyano, trifluoromethyl, deuterated or undeuterated methyl, deuterated or undeuterated isopropyl, deuterated or undeuterated tert-butyl, deuterated or undeuterated phenyl.

2. The polycyclic diboron nitrogen compound according to claim 1, characterized in that, Rings A, B, C, and D are each independently selected from substituted or unsubstituted unsaturated carbon rings having 6-12 carbon atoms, wherein at least one ring is selected from... or .

3. The polycyclic diboron nitrogen compound according to claim 1, characterized in that, R is independently selected from hydrogen, deuterium, cyano, trifluoromethyl, deuterated or undeuterated C. 1- C4 alkyl, substituted or unsubstituted phenyl.

4. The polycyclic diboron nitrogen compound according to claim 1, characterized in that, The specific structure of this compound is as follows: ； ； ； ； ； ； ； ； ； ； ； ； ； ； 。 5. An organic electroluminescent device, comprising an anode, a cathode, and an organic functional layer disposed between the anode and the cathode, the organic functional layer comprising a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer, characterized in that, The light-emitting layer comprises at least one of the polycyclic diboron nitrogen compounds according to any one of claims 1 to 4.

6. The organic electroluminescent device according to claim 5, wherein the light-emitting layer comprises a host material and a guest material, characterized in that, The guest material comprises at least one of the polycyclic diboron nitrogen compounds according to any one of claims 1 to 4.

7. The organic electroluminescent device according to claim 5, 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.

Images