A heterocyclic compound containing boron and nitrogen and use thereof

Abstract

The application provides a heterocyclic compound containing boron and nitrogen and an application thereof, and a structure general formula thereof is shown in the following formula (a), formula (b), formula (c) or formula (d): wherein, X1-X 16 are independently selected from CR0 or N atom, and at least one is N atom; Y and Z are independently selected from O, S, Se, CR1R2 or NR3; Ar1, Ar2 and Ar3 are independently selected from hydrogen, alkyl, substituted or unsubstituted aryl and substituted or unsubstituted heteroaryl. The heterocyclic compound of the application realizes multiple resonance effects by constructing N-B-N, O-B-N, S-B-N, Se-B-N and C-B-N between the donor and the acceptor at specific positions of the polycyclic aromatic compound skeleton, so that the emission spectrum is narrowed, the color purity is higher, and a high-efficiency MR-TAD device can be prepared.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent materials, specifically to a boron- and nitrogen-containing heterocyclic compound and its applications. Background Technology

[0002] Organic light-emitting diode (OLED) displays represent the next generation of flat panel display technology following liquid crystal displays (LCDs). Display technology based on OLEDs boasts advantages such as flexibility, ultra-lightweight, ultra-thin design, low energy consumption, wide viewing angle, active light emission, and fast response speed, holding a crucial position in the current and future display technology field. With the increasing demands of next-generation ultra-high-definition display technologies, the requirements for the color purity of luminescent materials are becoming increasingly stringent. According to the color coordinates published by the International Telecommunication Union (ITU) in 1931, these are (0.708, 0.292), (0.170, 0.979), and (0.131, 0.046). This places unprecedented demands on the color purity and color gamut standards of current and future displays. Developing OLED display technology that meets the BT2020 requirements has become a critical issue that urgently needs to be addressed in this scientific and technological field.

[0003] The color purity of the three primary color luminescent materials determines the color gamut of the display, and their color purity depends on the peak position, full width at half maximum (FWHM), shoulder peaks, and baseline of the emission spectrum. A narrower FWHM and fewer or no shoulder peaks are more conducive to improving the color purity of the emission spectrum. For OLED displays, although optical techniques such as filters or microcavity effects can be used to narrow the spectrum and obtain a high-color-purity emission spectrum, these processes significantly increase power consumption and product cost, and also reduce actual luminous efficiency, resulting in energy waste. The key to OLED display technology's ability to exhibit high color purity and a wide color gamut lies in organic electroluminescent materials. Therefore, developing organic electroluminescent materials with narrow-band emission characteristics to achieve displays that meet BT2020 requirements is of paramount importance. Multiple resonance (MR) molecules based on B / N polycyclic aromatic hydrocarbon frameworks have become cutting-edge materials in the OLED field due to their excellent photophysical properties. Constructing MR molecular frameworks with various functional groups to achieve ideal performance has become an emerging topic in materials chemistry.

[0004] As materials for organic light-emitting devices (OLEDs), various materials have been developed in the industry. In particular, thermally active delayed fluorescence materials (TADFs) have played a significant role in improving device efficiency. However, due to the effective separation of the highest occupied orbital (HOMO) and lowest unoccupied orbital (LUMO) in TADF materials, intramolecular charge transfer mainly occurs under the action of an electric field, resulting in a large Stokes shift, a wide full width at half maximum (FWHM) of the emission spectrum, and a decrease in color purity. In order to reduce the Stokes shift of the luminescent material and further improve the photoelectric properties of organic light-emitting materials, such as color purity and efficiency, especially the luminescence performance of blue light materials, it is necessary to provide a new boron-containing organic light-emitting material that enables the molecule to have higher singlet (S1) and triplet (T1) energies, thereby obtaining a shorter wavelength emission band. At the same time, it maintains the inherent multiple resonance (MR) characteristics of boron-intercalated conjugated aromatic compounds, thus obtaining a high-performance, narrow-spectral emission, blue-shifted, and structurally diverse MR-TADF material. Summary of the Invention

[0005] To address the technical challenges of reducing Stokes shift in luminescent materials and further improving the photoelectric properties of organic electroluminescent materials, such as color purity and efficiency, especially the luminescence performance of blue light-emitting materials, this invention aims to provide a boron- and nitrogen-containing heterocyclic compound and its applications.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows.

[0007] A heterocyclic compound containing boron and nitrogen has the following general structural formula: (a), (b), (c), or (d) as shown below:

[0008]

[0009] Among them, X1, X2, X3, X4, X5, X6, X7, X8, X9, X 10 X 11 X 12 X 13 X 14 X 15 X 16Each of the following is independently selected from CR0 or N atoms, and at least one of them is an N atom; RO is selected from hydrogen, deuterium, or methyl; Y and Z are independently selected from O, S, Se, CR1R2, or NR3; R1, R2, and R3 are independently selected from hydrogen, C1-C6 alkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl; Ar1, Ar2, and Ar3 are independently selected from hydrogen, C1-C6 alkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl; in formula (a), (b), (c), or (d), any H atom bonded to a carbon atom can be deuterated; the heteroaryl is an N-containing heteroaryl, an O-containing heteroaryl, or an S-containing heteroaryl.

[0010] Furthermore, when Y and Z are independently selected from CR1R2 or NR3, R1 and R2 are independently selected from hydrogen, deuterium, or methyl, respectively; R3 is selected from substituted or unsubstituted phenyl, or substituted or unsubstituted deuterated phenyl; when R3 is selected from substituted phenyl or substituted deuterated phenyl, the substituent is methyl.

[0011] Furthermore, Ar1, Ar2, and Ar3 are each independently selected from hydrogen, C1-C4 alkyl groups, and groups represented by formula (I), (II), (III), (IV), or (V):

[0012]

[0013] Among them, R4, R5, R6, R7, R8, R9, R 10 Alkyl groups selected independently from C1 to C4; in formulas (I), (II), (III), (IV), and (V), any H atom bonded to a carbon atom can be deuterated.

[0014] Furthermore, the group represented by formula (I) is selected from one of the following structural formulas:

[0015]

[0016] Furthermore, the group represented by formula (II) is selected from one of the following structural formulas:

[0017]

[0018] Furthermore, the group represented by formula (III) is selected from one of the following structural formulas:

[0019]

[0020] Furthermore, the group represented by formula (IV) is selected from one of the following structural formulas:

[0021]

[0022] Furthermore, the groups represented by formulas (V), (VI), and (VII) are selected from one of the following structural formulas:

[0023]

[0024] Specifically, it refers to one of the following compounds:

[0025]

[0026]

[0027]

[0028]

[0029]

[0030] The present invention also provides an application of the boron- and nitrogen-containing heterocyclic compound in an organic electroluminescent device.

[0031] The present invention also provides an organic electroluminescent device, comprising a light-emitting layer, wherein the material of the light-emitting layer comprises the aforementioned boron- and nitrogen-containing heterocyclic compound. The present invention further provides an application of the aforementioned organic electroluminescent device in an organic electroluminescent display device.

[0032] The beneficial effects of this invention are:

[0033] 1. Compared with existing products, the boron and nitrogen-containing heterocyclic compounds of the present invention are multi-resonance thermally active delayed fluorescence materials. By constructing NBN atoms, OBN atoms, SBN atoms, Se-BN atoms, CBN atoms, etc., between donor and acceptor phases at specific positions of the polycyclic aromatic compound skeleton, a multi-resonance effect is achieved, resulting in a narrower emission spectrum and higher color purity, which can be used to prepare high-efficiency MR-TAD devices.

[0034] 2. Due to the interaction of B, N, O, S, Se, and C atoms, the boron-containing polycyclic intercalated aromatic compounds of the present invention have adjacent distribution of HOMO and LUMO electron clouds in the parent nucleus structure, thereby achieving a multiple resonance effect. This multiple resonance effect can reduce the Stokes shift of the molecule, narrow the emission spectrum, and increase the gap crossing reversal rate, thereby obtaining a high-efficiency, high-color-purity luminescent material.

[0035] 3. This invention provides a novel class of boron-containing heterocyclic conjugated aromatic compounds. These compounds, modified with specific groups, possess suitable frontier orbital energy levels, and the innovative series of compounds exhibit excellent performance as luminescent materials in organic light-emitting diode (OLED) devices. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of an organic electroluminescent element provided in an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures: 1. Substrate; 2. Anode layer; 3. Hole injection layer; 4. First hole transport layer; 5. Second hole transport layer; 6. Light-emitting layer; 7. Hole blocking layer; 8. Electron transport layer; 9. Electron injection layer; 10. Cathode layer. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods; reagents and materials, unless otherwise specified, are commercially available.

[0039] This invention provides a novel boron- and nitrogen-containing heterocyclic conjugated aromatic compound. By constructing a polycyclic intercalation type conjugated aromatic compound with boron, nitrogen, and oxygen atoms, the molecule possesses higher singlet (S1) and triplet (T1) energies, resulting in a shorter wavelength emission band. Simultaneously, it maintains the inherent multiple resonance (MR) characteristics of boron-intercalated conjugated aromatic compounds, yielding high-performance, narrow-spectral emission, blue-shifted spectra, and structurally diverse MR-TADF materials. Specifically, by constructing donor-acceptor alternating NBN, OBN, SBN, Se-BN, and CBN atoms at specific positions in the polycyclic aromatic compound skeleton, a multiple resonance effect is achieved, resulting in a narrower emission spectrum and higher color purity. Ar1, Ar2, and Ar3 can be the same or different; any H atom bonded to C can be deuterated; the introduction of N atoms on the benzene ring does not disrupt the multiple resonance characteristics of the core structure, allowing the material to still achieve narrow-spectral emission. Modification with auxiliary groups Ar1, Ar2, and Ar3 ensures that the material retains TADF properties, guaranteeing a high inter-gap cross-inversion rate (IRSC) and high fluorescence quantum efficiency.

[0040] The following provides specific synthetic methods for preparing several intermediates corresponding to the above compounds.

[0041] Intermediate 1:

[0042]

[0043] In the formula, m1, m2, and m3 are all halogens, and are selected from Cl, Br, I, or F, respectively.

[0044] Intermediate 2:

[0045]

[0046] In the formula, m4, m5, and m6 are all halogens, and are selected from Cl, Br, I, or F, respectively.

[0047] Intermediate 3:

[0048]

[0049] In the formula, m4′, m5′, and m7 are all halogens, and are selected from Cl, Br, I, or F, respectively.

[0050] The synthetic routes for the compounds shown in formulas (a), (b), (c), and (d) are provided below.

[0051]

[0052]

[0053] When m6 of intermediate 2 is hydrogen, it is intermediate 2′. When Z of intermediate 1 is hydrogen, it is intermediate 1′.

[0054]

[0055] In the formula, m4′ and m8 are both halogens, and are selected from Cl, Br, I or F, respectively.

[0056] Compounds 1–36 were prepared according to the synthetic route of the compound shown in formula (b); compounds 37–40 were prepared according to the synthetic route of the compound shown in formula (d); compounds 41–120 were prepared according to the synthetic route of the compound shown in formula (a); and compounds 121–132 were prepared according to the synthetic route of the compound shown in formula (c).

[0057] Below, we will provide specific examples of the synthesis methods for some boron- and nitrogen-containing heterocyclic compounds.

[0058] Example 1

[0059] The synthetic route for a boron- and nitrogen-containing heterocyclic compound is shown below:

[0060]

[0061]

[0062] Synthesis of intermediate A-1: ​​Under nitrogen protection, 2-amino-5-chlorophenol (53.9 g, 375.0 mmol), 3-bromo-4-fluoropyridine (60.0 g, 340.9 mmol), sodium tert-butoxide (108.1 g, 1.12 mol), Pd₂(dba)₃ (3.1 g, 3.5 mmol), XantPhos (2.9 g, 6.9 mmol), and dry toluene (1 L) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 63.6 g of white solid A-1, yield 78.2%.

[0063] Synthesis of intermediate A-2: Under nitrogen protection, A-1 (60.0 g, 251.4 mmol) and DMF (800 mL) were added sequentially to a reaction flask, and the mixture was heated to 120 °C. Sodium hydroxide (25.1 g, 628.5 mmol) was then added in portions, and the reaction was continued at this temperature for 10 h. After the reaction was complete, the system was cooled to room temperature. The reaction solution was poured into a large amount of ice water, resulting in the formation of a white precipitate. The precipitate was adjusted to neutral with 2N hydrochloric acid solution and collected by vacuum filtration. The precipitate was washed sequentially with water and ethanol. Finally, the resulting filter cake was dissolved in an appropriate amount of toluene / ethanol and recrystallized to give 32.7 g of white solid A-2, with a yield of 59.6%.

[0064] Synthesis of intermediate A-3: Under nitrogen protection, A-2 (30.0 g, 137.2 mmol), deuterated phenylboronic acid (17.6 g, 150.9 mmol), potassium carbonate (28.4 g, 205.8 mmol), tetrabutylammonium bromide (2.2 g, 6.9 mmol), toluene (500 mL), ethanol (200 mL), and ultrapure water (100 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to obtain 25.5 g of white solid A-3, yield 72.7%.

[0065] Synthesis of intermediate A-4: Under nitrogen protection, 3,5-dibromo-4-chlorotert-butylbenzene (50.00 g, 153.2 mmol), quinoline-5-boronic acid (26.5 g, 153.2 mmol), potassium carbonate (31.7 g, 229.7 mmol), tetrabutylammonium bromide (2.5 g, 7.6 mmol), toluene (800 mL), ethanol (200 mL), and ultrapure water (100 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 43.8 g of white solid A-4, yield 76.3%.

[0066] Synthesis of intermediate A-5: Under nitrogen protection, intermediates A-3 (20.0 g, 78.3 mmol), A-4 (32.3 g, 86.2 mmol), sodium tert-butoxide (22.6 g, 235.0 mmol), Pd₂(dba)₃ (0.72 g, 0.78 mmol), tri-tert-butylphosphine (0.32 g, 1.57 mmol), and dry toluene (500 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 26.9 g of white solid A-5, yield 62.5%.

[0067] Synthesis of Compound 5: Under nitrogen protection, intermediate A-5 (25.0 g, 45.5 mmol) and xylene (400 mL) were added sequentially to a reaction flask. The system was cooled to -40 °C, and tert-butyllithium (42.7 mL, 68.3 mmol, 1.6 M) was added dropwise. After the addition was complete, the temperature was raised to 0 °C and stirring was continued for 2 h. Then, boron tribromide (28.5 g, 113.8 mmol) was added dropwise between -40 °C and -30 °C. After the addition was complete, the reaction was continued at 50 °C for 2 h. The system was then cooled to 0 °C, and DIEA (14.7 g, 113.8 mmol) was added. After the addition was complete, the temperature was gradually raised to 120 °C, and the reaction was continued at this temperature for 8 h. After the reaction was complete, the solvent was removed by vacuum distillation. The crude product was slurried with ethanol and recrystallized from toluene / ethanol to give 6.2 g of a pale yellow solid, with a yield of 25.9%. The mass spectrometry results of the obtained sample were: HR-MS (APCI): m / z 523.4103 [M+H] + C 36 H 21 Calculated OBN3 (%): C, 82.77; H, 4.05; O, 3.06; N, 8.04; Measured: C, 82.73; H, 4.06; O, 3.07; N, 8.02.

[0068] Example 2

[0069] The synthetic route for a boron- and nitrogen-containing heterocyclic compound is shown below:

[0070]

[0071] Synthesis of intermediate B-1: Under argon protection, 3-bromo-4-nitropyridine (50.0 g, 246.3 mmol), N-phenyl-3-benzidine (66.5 g, 270.9 mmol), sodium tert-butoxide (35.5 g, 369.5 mmol), Pd2(dba)3 (2.3 g, 2.5 mmol), XantPhos (2.1 g, 4.9 mmol), and toluene (1 L) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The mixture was washed with water until neutral, refluxed to remove water, passed through a silica gel column, concentrated by column chromatography, and recrystallized from the concentrate with a suitable amount of toluene / ethanol to give 73.5 g of white solid B-1, yield 81.2%.

[0072] Synthesis of intermediate B-2: Intermediate B-1 (70 g, 190.5 mmol) was added to a three-necked flask, followed by triethyl phosphite (800 mL). The mixture was heated to 120 °C and reacted for 10 h. After the reaction was complete, the mixture was cooled to room temperature, and ethanol (800 mL) was added, followed by petroleum ether. The mixture was stirred until a white solid precipitated. The filter cake was washed with petroleum ether and then dissolved in toluene. The solution was passed through a silica gel column. After concentration, the solution was recrystallized with a suitable amount of toluene / ethanol to give 42.0 g of white solid B-2, with a yield of 65.8%.

[0073] Synthesis of intermediate B-3: Following the synthesis method of intermediate A-5, intermediate A-3 was replaced with B-2, with a yield of 67.2%.

[0074] Synthesis of Compound 8: Following the synthetic method of Compound 5, intermediate A-5 was replaced with B-3, yielding 31.3%. The mass spectrometry results of the obtained sample were: HR-MS (APCI): m / z 603.5961

[0075] [M+H] + C 42 H 31 BN4 (%) Calculated values: C, 83.72; H, 5.19; N, 9.30; Measured values: C, 83.75; H, 5.22; N, 9.27.

[0076] Example 3

[0077] The synthetic route for a boron- and nitrogen-containing heterocyclic compound is shown below:

[0078]

[0079] Synthesis of intermediate C-1: Under argon protection, 1,3-dibromo-2-chloro-5-iodobenzene (80.0 g, 201.9 mmol), 3,6-di-tert-butylcarbazole (56.4 g, 201.9 mmol), sodium tert-butoxide (38.8 g, 403.8 mmol), Pd₂(dba)₃ (1.8 g, 2.0 mmol), XantPhos (1.7 g, 4.0 mmol), and toluene (1 L) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The mixture was washed with water until neutral, refluxed to remove water, passed through a silica gel column, concentrated by column chromatography, and recrystallized from the concentrate with a suitable amount of toluene / ethanol to give 84.3 g of white solid C-1, yield 76.2%.

[0080] Synthesis of intermediate C-2: Following the synthesis method of intermediate A-4, 3,5-dibromo-4-chlorotert-butylbenzene was replaced with C-1, with a yield of 71.5%.

[0081] Synthesis of intermediate C-3: Under nitrogen protection, 4-amino-3-mercaptopyridine (40.0 g, 317.0 mmol), 3-bromo-4-fluorotert-butylbenzene (80.6 g, 348.7 mmol), sodium tert-butoxide (60.9 g, 634.0 mmol), Pd2(dba)3 (2.9 g, 3.2 mmol), XantPhos (2.51 g, 6.0 mmol), and toluene (1 L) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The mixture was washed with water until neutral, refluxed to remove water, passed through a silica gel column, concentrated by column chromatography, and recrystallized from the concentrate with a suitable amount of toluene / ethanol to give 68.0 g of white solid C-3, yield 77.6%.

[0082] Synthesis of intermediate C-4: Under nitrogen protection, intermediate C-3 (65.0 g, 235.2 mmol), cesium carbonate (114.9 g, 352.8 mmol), and DMF (800 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 6 h. After the reaction was complete, the system was cooled to room temperature. A large amount of water was poured in under stirring, and a white precipitate formed. The precipitate was collected by suction filtration. The precipitate was washed successively with water and ethanol. Finally, the obtained filter cake was dissolved in an appropriate amount of toluene / ethanol by weight to give 52.4 g of white solid C-4, with a yield of 86.9%.

[0083] Synthesis of intermediate C-5: Under nitrogen protection, intermediates C-2 (60.0 g, 100.7 mmol), C-4 (25.8 g, 100.7 mmol), sodium tert-butoxide (19.3 g, 201.4 mmol), Pd2(dba)3 (0.92 g, 1.0 mmol), tri-tert-butylphosphine (0.4 g, 2.0 mmol), and dry toluene (800 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 46.8 g of white solid C-5, yield 65.3%.

[0084] Synthesis of Compound 18: Following the synthetic method of Compound 5, intermediate A-5 was replaced with C-5, yielding 29.6%. The mass spectrometry results of the obtained sample were: HR-MS (APCI): m / z 745.8186.

[0085] [M+H] + Calculated values ​​of C50H45BN4S (%): C, 80.63; H, 6.09; N, 7.52; Measured values: C, 80.67; H, 6.12; N, 7.50.

[0086] Example 4

[0087] The synthetic route for a boron- and nitrogen-containing heterocyclic compound is shown below:

[0088]

[0089] Synthesis of intermediate D-1: Following the synthesis method of intermediate C-1, 3,6-di-tert-butylcarbazole was replaced with di(4-tert-butylphenyl)amine, with a yield of 79.2%.

[0090] Synthesis of intermediate D-2: Following the synthesis method of intermediate C-2, intermediate C-1 was replaced with intermediate D-1, with a yield of 72.3%.

[0091] Synthesis of intermediate D-3: Under argon protection, methyl 2-aminonicotinic acid (50.0 g, 328.6 mmol), 4-bromo-tert-butylbenzene (77.0 g, 361.5 mmol), sodium tert-butoxide (63.1 g, 657.2 mmol), Pd₂(dba)₃ (1.56 g, 1.7 mmol), XantPhos (1.44 g, 3.4 mmol), and toluene (1 L) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The mixture was washed with water until neutral, refluxed to remove water, passed through a silica gel column, concentrated by column chromatography, and recrystallized with a suitable amount of toluene / ethanol to give 77.3 g of white solid C-1, yield 82.7%.

[0092] Synthesis of intermediate D-4: Under nitrogen protection, intermediate D-3 (50.0 g, 197.8 mmol) and dry tetrahydrofuran (1 L) were added sequentially to a reaction flask. The system was cooled to 0 °C, and methylmagnesium bromide (370.9 mL, 593.4 mmol, 1.6 M) was added dropwise. After the addition was complete, the mixture was heated to room temperature and stirred for 8 h. After the reaction was complete, methanol was added to quench the reaction. The organic phase was concentrated to 1 / 3 under reduced pressure, dissolved completely in toluene, and washed with water until neutral. The organic phase was dried with anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure to obtain 39.5 g of a pale yellow solid. The obtained pale yellow solid was added to toluene (200 mL), followed by phosphoric acid (300 mL). The mixture was heated at 80 °C for 4 h. After the reaction was completed, the mixture was cooled to room temperature and poured into ice water to precipitate the solid. The resulting filter cake was dissolved in toluene and washed with water until neutral. After concentration, it was recrystallized with an appropriate amount of toluene / ethanol to give 27.7 g of white solid D-4, with a yield of 52.6%.

[0093] Synthesis of intermediate D-5: Under nitrogen protection, intermediates D-2 (56.1 g, 93.8 mmol), D-4 (25.0 g, 93.8 mmol), sodium tert-butoxide (18.0 g, 187.6 mmol), Pd2(dba)3 (0.86 g, 0.94 mmol), tri-tert-butylphosphine (0.38 g, 1.9 mmol), and dry toluene (800 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 50.9 g of white solid D-5, yield 69.4%.

[0094] Synthesis of Compound 27: Following the synthetic method of Compound 5, intermediate A-5 was replaced with D-5, yielding 23.7%. The mass spectrometry results of the obtained sample were: HR-MS (APCI): m / z 757.9257.

[0095] [M+H] + Calculated values ​​of C53H53BN4 (%): C, 84.11; H, 7.06; N, 7.40; Measured values: C, 84.14; H, 7.07; N, 7.37.

[0096] Example 5

[0097] The synthetic route for a boron- and nitrogen-containing heterocyclic compound is shown below:

[0098]

[0099] Synthesis of intermediate E-1: Following the synthesis method of intermediate C-1, 3,6-di-tert-butylcarbazole was replaced with N-phenyl-3-carbazoleboronic acid, with a yield of 77.5%.

[0100] Synthesis of intermediate E-2: Following the synthesis method of intermediate C-2, intermediate C-1 was replaced with intermediate E-1, with a yield of 74.2%.

[0101] Synthesis of intermediate E-3: Following the synthesis method of intermediate B-1, N-phenyl-3-benzidine was replaced with 3-tert-butyl-N-aniline, with a yield of 81.7%.

[0102] Synthesis of intermediate E-4: Following the synthesis method of intermediate B-2, intermediate B-1 was replaced with intermediate E-3, with a yield of 69.7%.

[0103] Synthesis of intermediate E-5: Under nitrogen protection, intermediates E-2 (40.0 g, 71.4 mmol), E-4 (22.5 g, 71.4 mmol), sodium tert-butoxide (13.7 g, 142.8 mmol), Pd2(dba)3 (0.64 g, 0.7 mmol), tri-tert-butylphosphine (0.28 g, 1.4 mmol), and dry toluene (700 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 36.0 g of white solid D-5, yield 63.5%.

[0104] Synthesis of compound 32: Following the synthetic method of compound 5, intermediate A-5 was replaced with E-5, yielding 28.3%. The mass spectrometry results of the obtained sample were: HR-MS (APCI): m / z 768.7923 [M+H] + Calculated values ​​of C54H38BN5 (%): C, 84.48; H, 4.99; N, 9.12; Measured values: C, 84.50; H, 5.02; N, 9.11.

[0105] Example 6

[0106] The synthetic route for a boron- and nitrogen-containing heterocyclic compound is shown below:

[0107]

[0108] Synthesis of intermediate F-1: Following the synthesis method of intermediate A-5, intermediate A-3 was replaced with 4-amino-3-chloropyridine, with a yield of 70.8%.

[0109] Synthesis of intermediate F-2: Under argon protection, intermediate F-1 (40.00 g, 94.7 mmol), potassium carbonate (26.1 g, 189.4 mmol), tert-valerate (0.48 g, 4.7 mmol), palladium acetate (0.21 g, 0.95 mmol), tri-tert-butylphosphine (0.38 g, 1.90 mmol), and N-pyrrolidone (700 mL) were added sequentially to a reaction flask, and the mixture was heated to 130 °C for 6 h. After the reaction was complete, the system was cooled to room temperature. A large amount of water was added under stirring, resulting in the formation of a white precipitate. The precipitate was filtered and completely dissolved in toluene. Most impurities were removed by column chromatography. The eluent was concentrated and recrystallized from a suitable amount of toluene / ethanol (volume ratio 2:1) to obtain 28.7 g of white solid F-2, with a yield of 78.5%.

[0110] Synthesis of intermediate F-3: Under argon protection, 3,6-di-tert-butyldeuterated carbazole (30.0 g, 109.7 mmol), 1-bromo-3-iodobenzene (31.0 g, 109.7 mmol), sodium tert-butoxide (21.0 g, 219.4 mmol), Pd₂(dba)₃ (1.0 g, 1.1 mmol), XantPhos (0.9 g, 2.2 mmol), and toluene (600 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The mixture was washed with water until neutral, refluxed to remove water, passed through a silica gel column, concentrated by column chromatography, and recrystallized from the concentrate with a suitable amount of toluene / ethanol (volume ratio 1:2) to give 35.7 g of white solid F-3, yield 75.9%.

[0111] Synthesis of intermediate F-4: Under nitrogen protection, intermediates F-2 (25.0 g, 64.8 mmol), F-3 (27.7 g, 64.8 mmol), sodium tert-butoxide (12.4 g, 129.6 mmol), Pd2(dba)3 (0.6 g, 0.65 mmol), tri-tert-butylphosphine (0.26 g, 1.3 mmol), and dry toluene (500 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 35.0 g of white solid F-4, yield 73.7%.

[0112] Synthesis of compound 40: Following the synthetic method of compound 5, intermediate A-5 was replaced with F-4, yield 22.9%. The mass spectrometry results of the obtained sample were: HR-MS (APCI): m / z 707.7336

[0113] [M+H] +Calculated values ​​of C50H39BN4 (%): C, 84.98; H, 5.56; N, 7.93; Measured values: C, 84.99; H, 5.58; N, 7.91.

[0114] Example 7

[0115] The synthetic route for a boron- and nitrogen-containing heterocyclic compound is shown below:

[0116]

[0117] Synthesis of intermediate G-1: Following the synthesis method of intermediate A-4, 3,5-dibromo-4-chloro-tert-butylbenzene was replaced with 1-fluoro-3-chloro-2,4-dibromobenzene, with a yield of 78.3%.

[0118] Synthesis of intermediate G-2: Following the synthesis method of intermediate F-3, 3,6-di-tert-butyldeuterated carbazole was replaced with di(4-isopropylphenyl)amine, with a yield of 82.1%.

[0119] Synthesis of intermediate G-3: Under argon protection, intermediate G-2 (50.0 g, 122.4 mmol), 2,6-dimethylaniline (16.3 g, 134.7 mmol), sodium tert-butoxide (23.5 g, 244.8 mmol), Pd2(dba)3 (1.1 g, 1.2 mmol), tri-tert-butylphosphine (0.49 g, 2.4 mmol), and toluene (800 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The mixture was washed with water until neutral, refluxed to remove water, passed through a silica gel column, concentrated by column chromatography, and recrystallized from the concentrate with a suitable amount of toluene / ethanol to give 42.9 g of white solid G-3, yield 78.2%.

[0120] Synthesis of intermediate G-4: Under nitrogen protection, intermediate G-3 (40.0 g, 89.2 mmol), 3-bromo-4-nitro-5-hydroxypyridine (19.5 g, 89.2 mmol), sodium tert-butoxide (17.1 g, 178.4 mmol), Pd2(dba)3 (0.82 g, 0.9 mmol), tri-tert-butylphosphine (0.36 g, 1.8 mmol), and dry toluene (800 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 38.0 g of white solid G-4, yield 72.6%.

[0121] Synthesis of intermediate G-5: Following the synthesis method of intermediate B-2, intermediate B-1 was replaced with intermediate G-4, yielding 63.4%. Synthesis of intermediate G-6: Under nitrogen protection, intermediate G-5 (20.0 g, 36.0 mmol), G-1 (12.1 g, 36.0 mmol), sodium tert-butoxide (6.9 g, 72 mmol), Pd2(dba)3 (0.33 g, 0.36 mmol), tri-tert-butylphosphine (0.15 g, 0.72 mmol), and dry toluene (500 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and recrystallized with an appropriate amount of toluene / ethanol to give 19.6 g of white solid F-4, yielding 67.3%. Synthesis of intermediate G-7: Following the synthesis method of intermediate C-4, intermediate C-3 was replaced with intermediate G-6, with a yield of 87.5%.

[0122] Synthesis of Compound 52: Following the synthetic method of Compound 5, intermediate A-5 was replaced with G-7, yielding 31.6%. The mass spectrometry results of the obtained sample were: HR-MS (APCI): m / z 764.7741

[0123] [M+H] + C 52 H 42 Calculated OBN5 (%): C, 81.78; H, 5.54; O, 2.09; N, 9.17; Measured: C, 81.79; H, 5.55; O, 2.06; N, 9.16.

[0124] Example 8

[0125] The synthetic route for a boron- and nitrogen-containing heterocyclic compound is shown below:

[0126]

[0127] Synthesis of intermediate H-1: Following the synthesis method of intermediate C-1, 1,3-dibromo-2-chloro-5-iodobenzene was replaced with 2-fluoro-4-bromonitrobenzene, with a yield of 71.9%.

[0128] Synthesis of intermediate H-2: Under nitrogen protection, intermediate H-1 (75 g, 179.2 mmol), 3-pyridinyl selenol (31.1 g, 197.1 mmol), cesium carbonate (87.6 g, 268.8 mmol), and DMF (1 L) were added sequentially to a reaction flask, and the mixture was heated to 120 °C for 6 h. After the reaction was complete, the system was cooled to room temperature. A large amount of water was added under stirring, resulting in the formation of a white precipitate. The precipitate was filtered and washed successively with water and ethanol. Finally, the precipitate was dissolved in an appropriate amount of toluene / ethanol and recrystallized to give 77.0 g of white solid H-2, with a yield of 77.2%.

[0129] Synthesis of intermediate H-3: Following the synthesis method of intermediate B-2, intermediate B-1 was replaced with intermediate H-2, with a yield of 61.8%.

[0130] Synthesis of intermediate H-4: Following the synthesis method of intermediate A-4, 3,5-dibromo-4-chlorotert-butylbenzene was replaced with 1-bromo-3-chloro-2,4-diiodobenzene, with a yield of 67.7%.

[0131] Synthesis of intermediate H-5: Under argon protection, intermediates H-3 (35.0 g, 66.7 mmol), H-4 (29.6 g, 66.7 mmol), sodium tert-butoxide (12.8 g, 133.4 mmol), Pd2(dba)3 (0.61 g, 0.67 mmol), XantPhos (0.56 g, 1.33 mmol), and toluene (600 mL) were added sequentially to a reaction flask, and the mixture was heated to reflux for 8 h. After the reaction was complete, the system was cooled to room temperature. The mixture was washed with water until neutral, refluxed to remove water, passed through a silica gel column, concentrated by column chromatography, and recrystallized with an appropriate amount of toluene / ethanol to give 41.2 g of white solid H-5, yield 73.4%.

[0132] Synthesis of intermediate H-6: Under nitrogen protection, intermediate H-5 (40.0 g, 47.5 mmol) and dry tetrahydrofuran (500 mL) were added sequentially to a reaction flask. The system was cooled to -78 °C, and n-butyllithium (28.5 mL, 71.3 mmol, 2.5 M) was added dropwise. After the addition was complete, the reaction was carried out for 1 h. Then, anhydrous acetone (4.1 g, 71.3 mmol) was slowly added. After the addition was complete, the temperature was slowly raised to room temperature and stirred for 2 h. The reaction was quenched with water. The organic phase was extracted with dichloroethane and washed with water until neutral. It was dried over anhydrous magnesium sulfate and concentrated to dryness for later use. Add glacial acetic acid (800 ml) and hydrochloric acid (80 ml) to the concentrate, reflux for 6 h, cool to room temperature, then pour the reaction solution into ice water to precipitate the solid. Filter the resulting filter cake and wash it with water and ethanol in sequence. Finally, dissolve the resulting filter cake in an appropriate amount of toluene / ethanol and recrystallize to obtain 30.3 g of white solid, with a yield of 79.6%.

[0133] Synthesis of Compound 74: Following the synthetic method of Compound 5, intermediate A-5 was replaced with H-6, yielding 29.3%. The mass spectrometry results of the obtained sample were: HR-MS (APCI): m / z 776.6938 [M+H] + Calculated values ​​of C49H41BN4Se (%): C, 75.88; H, 5.33; N, 7.22; Measured values: C, 75.92; H, 5.35; N, 7.19.

[0134] We performed T1 level and HOMO and LUMO level quantization calculations on some of the compounds provided in the above embodiments of the present invention and existing materials, respectively. The results are shown in Table 1:

[0135] Table 1. HOMO, LUMO, and triplet energy values ​​of the compounds of this invention.

[0136] compound HOMO(eV) LUMO(eV) <![CDATA[T1(eV)]]> Eg(eV) Compound 5 -5.422 2.510 2.103 2.912 Compound 8 -4.891 -2.308 1.757 2.582 Compound 18 -5.381 -2.600 1.935 2.781 Compound 27 -5.018 -2.138 1.918 2.880 Compound 32 -5.110 -2.420 1.897 2.690 Compound 40 -5.428 -2.689 1.843 2.739 Compound 52 -5.010 -2.220 1.897 2.790 Compound 74 -4.646 -2.204 1.652 2.442 BD-1 -5.243 -1.865 2.490 3.378

[0137] Note: The values ​​of the highest molecular occupied orbital (HOMO), the lowest molecular unoccupied orbital (LUMO), and the triplet energy (T1) are data calculated by simulation software.

[0138] Calculation results show that the energy level values ​​of the material are suitable, the electron cloud is mainly distributed in the parent nucleus, and the auxiliary groups such as carbazole and amino groups have little influence on the energy levels. The boron-nitrogen-containing parent nucleus has a high degree of conjugation, and the triplet state energy of the constructed molecule is low, enabling the emission of light blue, green, and yellow light.

[0139] Below, we will take some of the compounds provided in the above embodiments of the present invention as examples and apply them as light-emitting layer materials (main materials and / or doped dyes) to organic electroluminescent devices to verify their excellent effects.

[0140] Device Example 1

[0141] This embodiment provides an organic electroluminescent device, the specific structure of which is as follows: Figure 1 As shown, it includes a substrate 1, an anode layer 2, a hole injection layer 3, a first hole transport layer 4, a second hole transport layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9, and a cathode layer 10, which are stacked in sequence.

[0142] The anode layer 2 is made of indium tin oxide (ITO) with a high work function; the hole injection layer 3 is made of HATCN with a thickness of 5 nm; the first hole transport layer 4 is made of HT1 with a thickness of 60 nm; the second hole transport layer 5 is made of HT2 with a thickness of 15 nm; the light-emitting layer 6 uses mCBP as the host material and compound 5 as the dopant material with a doping mass ratio of 3% and a thickness of 30 nm; the hole blocking layer 7 is made of TPBi with a thickness of 10 nm; the electron transport layer 8 is made of ET-1 with a thickness of 35 nm; the electron injection layer 9 is made of Liq with a thickness of 2 nm; and the cathode layer is made of Al with a thickness of 100 nm.

[0143] The basic material structures used in each functional layer of the device are as follows:

[0144]

[0145] The specific fabrication steps of the above-mentioned organic electroluminescent device are as follows:

[0146] 1) Clean the ITO anode on the transparent glass or plastic substrate by ultrasonic cleaning with deionized water, acetone and ethanol for 20 minutes each, and then perform plasma treatment in an oxygen atmosphere for 5 minutes.

[0147] 2) On the ITO anode layer, a hole injection layer material HATCN with a thickness of 5nm is deposited by vacuum evaporation. This layer serves as the hole injection layer.

[0148] 3) Hole transport material HT1 with a thickness of 60nm is deposited on the hole injection layer by vacuum evaporation. This layer serves as the first hole transport layer.

[0149] 4) Hole transport material HT2 with a thickness of 15nm is deposited on the first hole transport layer HT1 by vacuum evaporation. This layer serves as the second hole transport layer.

[0150] 5) On the second hole transport layer, a light-emitting layer is co-deposited by vacuum evaporation, using mCPB as the host material and compound 5 as the light-emitting material, with a doping mass ratio of 3% and a thickness of 30nm;

[0151] 6) On the light-emitting layer, hole-blocking material TPBI with a thickness of 10nm is deposited by vacuum evaporation. This layer serves as the hole-blocking layer.

[0152] 7) Electron transport material ET-1 with a thickness of 35nm is deposited on the hole blocking layer by vacuum evaporation. This layer serves as the electron transport layer.

[0153] 8) On the electron transport layer, the electron injection material Liq is deposited by vacuum evaporation with a thickness of 2nm. This layer serves as the electron injection layer.

[0154] 9) On the electron injection layer, cathode Al is deposited by vacuum evaporation with a thickness of 100 nm. This layer is used as the cathode conductive electrode.

[0155] Device Example 2

[0156] Same as in Device Example 1, except that compound 8 is used as a dopant instead of compound 5.

[0157] Device Example 3

[0158] Same as in Device Example 1, except that compound 18 is used as a dopant instead of compound 5.

[0159] Device Example 4

[0160] Same as in Device Example 1, except that compound 27 is used as a dopant instead of compound 5.

[0161] Device Example 5

[0162] Same as in Device Example 1, except that compound 32 is used as a dopant instead of compound 5.

[0163] Device Example 6

[0164] Same as in Device Example 1, except that compound 40 is used as a dopant instead of compound 5.

[0165] Device Example 7

[0166] Same as in Device Example 1, except that compound 52 is used as a dopant instead of compound 5.

[0167] Device Example 8

[0168] Same as in Device Example 1, except that compound 74 is used as a dopant instead of compound 5.

[0169] Device Comparison Example 1

[0170] Same as in Device Example 1, except that BD-1 is used as a substitute for compound 5 for dopant.

[0171] The constituent components of the different devices prepared in Device Examples 1-8 and Device Comparative Example 1 of the present invention are shown in Table 2:

[0172] Table 2. Comparison of the constituent components of organic electroluminescent devices in various device embodiments.

[0173]

[0174] Each group of organic light-emitting diodes (OLEDs) had its cathode and anode connected using a known driving circuit. The voltage-efficiency-brightness relationship of the OLED devices was tested using a Keithley 2400 power supply and a PR670 photometer, following standard methods. The test results are shown in Table 3.

[0175] Table 3. Performance results of organic electroluminescent devices in each group

[0176]

[0177]

[0178] As shown in Table 3, the compounds provided by this invention exhibit excellent performance when used as luminescent materials in OLED devices. For example, compound 5 in device example 1, compared to BD-1 in device comparative example 1, shows a 22.5% increase in luminous efficiency, a narrower emission spectrum, and higher color purity as a light blue light material. It is evident that using the compounds of this invention as luminescent materials, compared to existing materials applied to OLED devices, results in superior photoelectric properties such as luminous efficiency and color purity, demonstrating significant application value and promising industrialization prospects in OLED devices.

[0179] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heterocyclic compound containing boron and nitrogen, characterized by, Specifically one of the following compounds: 。 2. Use of the boron and nitrogen containing heterocyclic compound according to claim 1 in an organic electroluminescence device.

3. An organic electroluminescent device comprising an emission layer, characterized in that The material of the light emitting layer comprises the boron and nitrogen containing heterocyclic compound according to claim 1.

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