A boron-nitrogen-based isoquinolinone derivative and a method for preparing the same

Abstract

This invention relates to the field of organic synthesis technology, and discloses a boron-based isoquinolinone derivative and its preparation method. Using methyl isoquinolinone as the main acceptor luminescent core, it is coupled with luminescent cores such as boraxazole, boraxphenoxazine, and boraxdimethylacridine via a Suzuki coupling reaction to prepare a pure organic luminescent material. This material is not a traditional fluorescent material; instead, it utilizes the electron-deficient properties of boron to alter the electron transfer characteristics and electron cloud distribution between boraxazole and other groups and methyl isoquinolinone, thereby significantly improving the material's luminescent performance. The material has a fluorescence emission peak at 496 nm, making it a good green luminescent material. Its maximum half-width is only 29 nm, and its fluorescence quantum yield is 84%. It also exhibits thermally activated delayed fluorescence and good thermal stability, showing broad application prospects in multiple fields such as organic electroluminescence, forensic fingerprint recognition, and bioimaging.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a boron-nitroisoquinoline ketone derivative and its preparation method. Background Technology

[0002] Isoquinolinones, as structural units of natural products and synthetic compounds with significant physiological activities, have seen recent research primarily focused on their synthesis methods. These derivatives exhibit antagonistic effects and enzyme inhibitory activity, possessing medicinal value in areas such as cancer, cerebral infarction, anti-tumor activity, anti-allergy, antibacterial and anti-inflammatory properties, anti-cytotoxic effects, and lowering systolic blood pressure. However, research linking isoquinolinone derivatives to optoelectronic materials is extremely rare.

[0003] The carbonyl group in the isoquinolinone structure is a strong electron-withdrawing group. The benzene ring and nitrogen atom fused to it can act as electron-donating parts, forming a "push-pull" electron structure. This facilitates intramolecular charge transfer and is a key mechanism for achieving efficient luminescence, especially long-wavelength luminescence. Introducing another electron-withdrawing group at the 4 or 6 position of the isoquinolinone can construct purely organic luminescent materials. These materials possess a rigid planar structure and exhibit good thermal stability and film-forming properties.

[0004] While donor-acceptor type third-generation thermally activated delayed fluorescence (TADF) materials can achieve highly efficient electroluminescence with 100% internal quantum efficiency, their over-reliance on intramolecular or intermolecular charge transfer characteristics results in a broad emission spectrum and insufficient color purity, making it difficult to meet the requirements of next-generation display technologies for high color purity and high brightness. Furthermore, most donor-acceptor type TADF materials have long triplet exciton lifetimes, making them prone to triplet-triplet annihilation, triplet-polaron annihilation, and singlet-singlet annihilation, leading to a significant roll-off in device efficiency.

[0005] The application of multiple resonance thermally activated delayed fluorescence (MR-TADF) materials in organic light-emitting diodes (OLEDs) is rapidly emerging. Their main characteristic is an extremely narrow emission spectrum, with a full width at half maximum (FWHM) comparable to that of inorganic OLEDs and quantum dots. In the construction of MR-TADF materials, electron-deficient boron atoms are introduced into the structural units to form boron-nitrogen-based MR-TADF materials. These materials are constructed with nitrogen atoms as donors and boron atoms as acceptors, achieving short-range charge transfer through an embedded structure where the HOMO (Homogeneous Oxidant Motion) is distributed in the nitrogen-containing part and the LUMO (Low Luminous Oxidant Motion) in the boron-containing part. However, the types of luminescent cores in existing boron-nitrogen-based MR-TADF materials are limited, and their binding modes with isoquinolinone structural units and corresponding synthetic methods have not been reported. Therefore, developing novel luminescent materials with isoquinolinones as luminescent cores coupled with structural units such as boraxazole, boraxphenoxazine, and boraxdimethylacidine, and their preparation methods, is of significant research importance. Summary of the Invention

[0006] The purpose of this invention is to provide a boron-nitroisoquinoline ketone derivative and its preparation method, so as to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a boron-nitroisoquinoline ketone derivative, the general structural formula of which is as follows:

[0008]

[0009] R1 is boraxazole, boraxphenoxazine, boraxdimethylacidine, o-benzazole, m-benzazole, p-benzazole, or triphenylamine, and the linking site between R1 and the isoquinolinone core is at position 4 or 6 of the isoquinolinone structure.

[0010] According to the above technical solution, R1 is set to any one of the following ac:

[0011] .

[0012] According to the above technical solution, the derivative is any one of the following compounds A to F:

[0013] .

[0014] A method for preparing a boron-nitroisoquinoline ketone derivative includes the following steps:

[0015] Step 1: Under nitrogen protection, using ultra-dry N,N-dimethylformamide as solvent, 3,6-di-tert-butylcarbazole, phenoxazine or dimethylacridine is mixed with cesium carbonate, stirred at room temperature, and then 2-bromo-1,3-difluorobenzene is added. After post-treatment, intermediate 1 is obtained.

[0016] Step 2: Under nitrogen protection, intermediate 1 is dissolved in anhydrous tert-butylbenzene, and n-butyllithium, boron tribromide and N,N-diisopropylethylamine are added in sequence, and intermediate 2 is obtained by cyclization reaction;

[0017] Step 3: Under ice bath conditions, using N,N-dimethylformamide as the reaction solvent, intermediate 2 and an equimolar amount of N-bromosuccinimide were reacted in N,N-dimethylformamide at room temperature, and after post-treatment, intermediate 3 was obtained.

[0018] Step 4: Under nitrogen protection, using tetrahydrofuran as the reaction solvent, intermediate 3 is reacted with n-butyllithium and trimethyl borate to obtain intermediate 4;

[0019] Step 5: Under nitrogen protection, intermediate 4 obtained in step 4 is coupled with 4-bromo-2-methylisoquinoline-1(2H)-one or 6-bromo-2-methylisoquinoline-1(2H)-one in the presence of Pd(PPh3)4 and potassium carbonate in a mixed solvent of toluene and ethanol or 1,4-dioxane to obtain the target product.

[0020] According to the above technical solution, the reaction temperature in step 1 is 155℃ and the reaction time is 24 hours.

[0021] According to the above technical solution, the cyclization reaction in step 2 includes: adding n-butyllithium at -78°C, heating to 60°C and reacting for 2 hours, then cooling to -78°C and adding boron tribromide, restoring to room temperature and adding N,N-diisopropylethylamine, and finally heating to 120°C and reacting for 12 hours.

[0022] According to the above technical solution, in step 4, the molar ratio of n-butyllithium to intermediate 3 is 1.5:1, and the molar ratio of trimethyl borate to intermediate 3 is 2:1. The reaction is carried out by adding n-butyllithium at -78°C, followed by adding trimethyl borate and heating the reaction for 12 hours.

[0023] According to the above technical solution, another way to prepare borate intermediate 4 in step 4 is to react intermediate 2 with pinacol diboronate, tricyclohexylphosphine, and potassium acetate in 1,4-dioxane at 100°C for 12 hours.

[0024] According to the above technical solution, the reaction temperature of the Suzuki coupling reaction in step 5 is 80-100℃, and the reaction time is 12 hours.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] (1) The boron-nitroisoquinoline ketone derivative of the present invention has excellent optical properties. Its fluorescence emission peak is located at 496 nm, making it a good green light emitting material. Its maximum half-width is only 29 nm, exhibiting significant narrow-band emission characteristics and a fluorescence quantum yield of up to 84%.

[0027] (2) The boron-nitroisoquinoline ketone derivative of the present invention has thermally activated delayed fluorescence characteristics. Time-resolved spectral analysis shows that it has both instantaneous fluorescence lifetime and delayed fluorescence lifetime, and can make full use of singlet and triplet excitons to achieve efficient luminescence.

[0028] (3) The boron-nitroisoquinoline ketone derivative of the present invention has excellent thermal stability. Thermogravimetric analysis results show that its thermal decomposition temperature exceeds 400℃, which is beneficial to improving the stability and working life of the light-emitting device.

[0029] (4) The boron-nitrogen-based isoquinolinone derivatives of the present invention have shown broad application prospects in many fields such as organic electroluminescence, criminal fingerprint recognition, and bioimaging. In particular, as a multi-resonance thermally activated delayed fluorescence material, it can meet the requirements of high color purity and high brightness for ultra-high-definition full color gamut display. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0031] Figure 1 This is the ultraviolet-visible absorption spectrum of boron-nitroisoquinoline ketone A of the present invention;

[0032] Figure 2 This is the fluorescence emission spectrum of boron-nitroisoquinoline ketone A of the present invention;

[0033] Figure 3 This invention relates to the fluorescence emission spectra of boron-nitroisoquinoline ketone A in different polar solvents;

[0034] Figure 4 This is the time-resolved spectrum of boron-nitroisoquinoline ketone A of the present invention;

[0035] Figure 5 This is a thermogravimetric analysis curve of boron-nitroisoquinoline ketone A of the present invention;

[0036] Figure 6 This is the orbital energy level distribution diagram of boron-nitroisoquinoline ketone A of the present invention; Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please see Figure 1-6 The present invention provides a technical solution: a boron-nitroisoquinoline ketone derivative, the general structural formula of which is as follows:

[0039]

[0040] Among them, R1 is boraxazole, boraxphenoxazine, boraxdimethylacidine, o-benzazole, m-benzazole, p-benzazole, triphenylamine, and the linking site between R1 and the isoquinolinone core is the 4th or 6th position of the isoquinolinone structure.

[0041] Specifically, R1 is set to any of the following ac:

[0042] ;

[0043] Specifically, the derivative is any one of the following compounds A through F:

[0044] ;

[0045] A method for preparing a boron-nitroisoquinoline ketone derivative includes the following steps:

[0046] Step 1: Under nitrogen protection, using ultra-dry N,N-dimethylformamide as solvent, 3,6-di-tert-butylcarbazole, phenoxazine or dimethylacridine is mixed with cesium carbonate, stirred at room temperature, and then 2-bromo-1,3-difluorobenzene is added. After post-treatment, intermediate 1 is obtained.

[0047] Step 2: Under nitrogen protection, intermediate 1 is dissolved in anhydrous tert-butylbenzene, and n-butyllithium, boron tribromide and N,N-diisopropylethylamine are added in sequence, and intermediate 2 is obtained by cyclization reaction;

[0048] Step 3: Under ice bath conditions, using N,N-dimethylformamide as the reaction solvent, intermediate 2 and an equimolar amount of N-bromosuccinimide were reacted in N,N-dimethylformamide at room temperature, and after post-treatment, intermediate 3 was obtained.

[0049] Step 4: Under nitrogen protection, using tetrahydrofuran as the reaction solvent, intermediate 3 is reacted with n-butyllithium and trimethyl borate to obtain intermediate 4;

[0050] Step 5: Under nitrogen protection, intermediate 4 obtained in step 4 is coupled with 4-bromo-2-methylisoquinoline-1(2H)-one or 6-bromo-2-methylisoquinoline-1(2H)-one in the presence of Pd(PPh3)4 and potassium carbonate in a mixed solvent of toluene and ethanol or 1,4-dioxane to obtain the target product;

[0051] Specifically, the reaction temperature in step 1 is 155°C and the reaction time is 24 hours;

[0052] Specifically, the cyclization reaction in step 2 includes: adding n-butyllithium at -78°C, heating to 60°C and reacting for 2 hours, cooling to -78°C and adding boron tribromide, restoring to room temperature and adding N,N-diisopropylethylamine, and finally heating to 120°C and reacting for 12 hours.

[0053] Specifically, in step 4, the molar ratio of n-butyllithium to intermediate 3 is 1.5:1, and the molar ratio of trimethyl borate to intermediate 3 is 2:1. The reaction is carried out by adding n-butyllithium at -78°C, followed by adding trimethyl borate and heating the reaction for 12 hours.

[0054] Specifically, another way to prepare borate intermediate 4 in step 4 is to react intermediate 2 with pinacol diboronate, tricyclohexylphosphine, and potassium acetate in 1,4-dioxane at 100°C for 12 hours.

[0055] Specifically, the Suzuki coupling reaction in step 5 is carried out at a temperature of 80-100°C for 12 hours.

[0056] The specific implementation method is as follows:

[0057] Example 1: Preparation of compound A

[0058] Preparation of Compound 1: Under nitrogen protection, 3,6-di-tert-butylcarbazole (tBu-Cz) (2.80 g, 10.0 mmol) and cesium carbonate (4.90 g, 15.0 mmol) were added sequentially to the reaction flask using ultradry N,N-dimethylformamide as the solvent. The mixture was stirred at room temperature for 30 min. Subsequently, 2-bromo-1,3-difluorobenzene (0.97 g, 5.0 mmol) was added under a nitrogen atmosphere, and the reaction temperature was set at 155 °C. The reaction was stirred continuously for 24 h. Thin-layer chromatography was used to monitor the reaction. After the reaction was terminated and cooled to room temperature, the reaction solution was slowly poured into 200 mL of distilled water and stirred continuously for 30 min. All the white solid precipitated out. The crude white solid product was collected by vacuum filtration and eluted with petroleum ether and petroleum ether:dichloromethane (8:1) as developing solvents. The product was further purified by column chromatography to obtain 3.30 g of pure white solid, with a yield of 92.0%.

[0059]

[0060] Preparation of Compound 2: A dry 250 mL three-necked flask was used to add Compound 1 (3.6 g, 5.0 mmol) and 100 mL of anhydrous tert-butylbenzene solvent. The mixture was stirred until dissolved, and the reaction system was protected with nitrogen. At -78 °C, n-butyllithium (3.43 mL, 5.5 mmol, 1.6 M) was added dropwise to the reaction system. After the addition was complete, the cryogenic apparatus was removed, and the reaction was stirred at 60 °C for 2 h. Subsequently, the heating was paused, and after the system was brought back to room temperature, the reaction system was placed at -78 °C. Boron tribromide (0.5 mL, 5.5 mmol) was added dropwise. After the addition was complete, the system was gradually brought back to room temperature. After 30 min, anhydrous N,N-diisopropylethylamine (1.0 mL, 5.5 mmol) was added dropwise to the system under ice-salt bath conditions. The system was then brought back to room temperature and stirred for 30 min, followed by heating to 120 °C and stirring for 12 h. After the reaction was completed and the temperature was brought back to room temperature, a phosphate buffer solution (pH = 6) was added to quench the reaction. The organic phase was collected and distilled under reduced pressure. Petroleum ether: dichloromethane (10:1) was used as the eluent, and the mixture was further purified by silica gel column chromatography to obtain 1.01 g of yellow solid, with a yield of 31.2%.

[0061]

[0062] Preparation of compound 3: Compound 2 (1.97 g, 3.08 mmol) was weighed into a 150 mL reaction flask, and 30 mL of N,N-dimethylformamide was added as the reaction solvent. The reaction flask was placed in an ice bath. NBS (0.55 g, 3.08 mmol) was dissolved in 10 mL of N,N-dimethylformamide. The NBS solution was slowly added dropwise to the reaction flask using a constant pressure dropping funnel. The mixture was magnetically stirred at room temperature for 10 h. After the reaction was completed, the reaction solution was quenched in 200 mL of saturated saline solution. The mixture was filtered under reduced pressure and dried to obtain 2.22 g of a yellow solid, with a yield of 89.2%.

[0063]

[0064] Preparation of compound 4: Compound 3 (1.50 g, 2.08 mmol) was added to a reaction flask using tetrahydrofuran as the solvent. The flask was cooled to -78°C under nitrogen protection. After 5 min, 2.5 mol·L⁻¹ n-butyllithium (1.25 mL, 3.12 mmol) was added, and the reaction was allowed to proceed at low temperature for 1 h. Then, trimethyl borate (1.25 mL, 4.16 mmol) was added, and the reaction was heated for 12 h. After the reaction was complete, dilute hydrochloric acid was added to adjust the solution to acidity. After extraction, concentration, and drying, the solution was purified by column chromatography to give 1.42 g of a yellow solid, with a yield of 46.2%.

[0065]

[0066] Preparation of Compound A: Under nitrogen protection, 4-bromo-2-methylisoquinoline-1(2H)-one (0.20 g, 0.84 mmol), Compound 4 (0.51 g, 0.76 mmol), Pd(PPh3)4 (27.0 mg, 0.024 mmol), 2 mol·L⁻¹ potassium carbonate (8.4 mL, 16.8 mmol) aqueous solution, and a mixed solvent of 30 mL toluene and 6 mL ethanol were added sequentially to a reaction flask. After three nitrogen purgings, the mixture was heated to 80 °C and stirred for 12 h. After the reaction was completed and cooled, the reaction mixture was quenched in 50 mL of saturated brine. The reactants were extracted with dichloromethane (50 mL × 3), the organic phases were combined, concentrated by rotary evaporation under reduced pressure, and dried over anhydrous magnesium sulfate. The crude product was purified by column chromatography using dichloromethane:petroleum ether (1:10) as the eluent to obtain 0.50 g of a yellow solid, with a yield of 83%.

[0067]

[0068] Example 2: Preparation of compound B

[0069] Preparation of Compound 1: Under nitrogen protection, 3,6-di-tert-butylcarbazole (tBu-Cz) (2.80 g, 10.0 mmol) and cesium carbonate (4.90 g, 15.0 mmol) were added sequentially to the reaction flask using ultradry N,N-dimethylformamide as the solvent. The mixture was stirred at room temperature for 30 min. Subsequently, 2-bromo-1,3-difluorobenzene (0.97 g, 5.0 mmol) was added under a nitrogen atmosphere, and the reaction temperature was set at 155 °C. The reaction was stirred continuously for 24 h. Thin-layer chromatography was used to monitor the reaction. After the reaction was terminated and cooled to room temperature, the reaction solution was slowly poured into 200 mL of distilled water and stirred continuously for 30 min. All the white solid precipitated out. The crude white solid product was collected by vacuum filtration and eluted with petroleum ether and petroleum ether:dichloromethane (8:1) as developing solvents. The product was further purified by column chromatography to obtain 3.30 g of pure white solid, with a yield of 92.0%.

[0070]

[0071] Preparation of Compound 2: A dry 250 mL three-necked flask was used to add Compound 1 (3.6 g, 5.0 mmol) and 100 mL of anhydrous tert-butylbenzene solvent. The mixture was stirred until dissolved, and the reaction system was protected with nitrogen. At -78 °C, n-butyllithium (3.43 mL, 5.5 mmol, 1.6 M) was added dropwise to the reaction system. After the addition was complete, the cryogenic apparatus was removed, and the reaction was stirred at 60 °C for 2 h. Subsequently, the heating was paused, and after the system was brought back to room temperature, the reaction system was placed at -78 °C. Boron tribromide (0.5 mL, 5.5 mmol) was added dropwise. After the addition was complete, the system was gradually brought back to room temperature. After 30 min, anhydrous N,N-diisopropylethylamine (1.0 mL, 5.5 mmol) was added dropwise to the system under ice-salt bath conditions. The system was then brought back to room temperature and stirred for 30 min, followed by heating to 120 °C and stirring for 12 h. After the reaction was completed and the temperature was brought back to room temperature, a phosphate buffer solution (pH = 6) was added to quench the reaction. The organic phase was collected and distilled under reduced pressure. Petroleum ether: dichloromethane (10:1) was used as the eluent, and the mixture was further purified by silica gel column chromatography to obtain 1.01 g of yellow solid, with a yield of 31.2%.

[0072]

[0073] Preparation of compound 3: Compound 2 (1.97 g, 3.08 mmol) was weighed into a 150 mL reaction flask, and 30 mL of N,N-dimethylformamide was added as the reaction solvent. The reaction flask was placed in an ice bath. NBS (0.55 g, 3.08 mmol) was dissolved in 10 mL of N,N-dimethylformamide. The NBS solution was slowly added dropwise to the reaction flask using a constant pressure dropping funnel. The mixture was magnetically stirred at room temperature for 10 h. After the reaction was completed, the reaction solution was quenched in 200 mL of saturated saline solution. The mixture was filtered under reduced pressure and dried to obtain 2.22 g of a yellow solid, with a yield of 89.2%.

[0074]

[0075] Preparation of compound 4: Compound 3 (1.50 g, 2.08 mmol) was added to a reaction flask using tetrahydrofuran as the solvent. The flask was cooled to -78°C under nitrogen protection. After 5 min, 2.5 mol·L⁻¹ n-butyllithium (1.25 mL, 3.12 mmol) was added, and the reaction was allowed to proceed at low temperature for 1 h. Then, trimethyl borate (1.25 mL, 4.16 mmol) was added, and the reaction was heated for 12 h. After the reaction was complete, dilute hydrochloric acid was added to adjust the solution to acidity. After extraction, concentration, and drying, the solution was purified by column chromatography to give 1.42 g of a yellow solid, with a yield of 46.2%.

[0076]

[0077] Preparation of compound B: Under nitrogen protection, 6-bromo-2-methylisoquinoline-1(2H)-one (0.20 g, 0.84 mmol), compound 4 (0.51 g, 0.76 mmol), Pd(PPh3)4 (27.0 mg, 0.024 mmol), 2 mol·L⁻¹ potassium carbonate (8.4 mL, 16.8 mmol) aqueous solution, and a mixed solvent of 30 mL toluene and 6 mL ethanol were added sequentially to a reaction flask. After three nitrogen purgings, the mixture was heated to 80 °C and stirred for 12 h. After the reaction was completed and cooled, the reaction mixture was quenched in 50 mL of saturated brine. The reactants were extracted with dichloromethane (50 mL × 3), the organic phases were combined, concentrated by rotary evaporation under reduced pressure, and dried over anhydrous magnesium sulfate. The crude product was purified by column chromatography using dichloromethane:petroleum ether (1:10) as the eluent to obtain 0.50 g of a yellow solid, with a yield of 83%.

[0078]

[0079] Example 3: Preparation of compound C

[0080] Preparation of Compound 5: Under nitrogen protection, phenoxazine (PXZ) (3.20 g, 17.5 mmol) and cesium carbonate (8.55 g, 26.3 mmol) were added sequentially to the reaction flask using ultradry N,N-dimethylformamide as the solvent. The mixture was stirred at room temperature for 30 min. Subsequently, 2-bromo-1,3-difluorobenzene (1.98 g, 8.7 mmol) was added under a nitrogen atmosphere, and the reaction temperature was set at 155 °C. The reaction was stirred continuously for 24 h. Thin-layer chromatography was used to monitor the reaction. After the reaction was terminated and cooled to room temperature, the reaction solution was slowly poured into 200 mL of distilled water and stirred continuously for 30 min. All the white solid precipitated. The crude pale yellow solid collected by vacuum filtration was eluted with petroleum ether and petroleum ether:dichloromethane (6:1) as the developing solvent, and further purified by column chromatography to obtain 4.20 g of pale yellow solid, with a yield of 89.2%.

[0081]

[0082] Preparation of Compound 6: A dry 250 mL three-necked flask was used to add Compound 5 (4.10 g, 7.4 mmol) and 100 mL of anhydrous tert-butylbenzene solvent. The mixture was stirred until dissolved, and the reaction system was protected with nitrogen. At -78 °C, n-butyllithium (5.09 mL, 8.1 mmol, 1.6 M) was added dropwise to the reaction system. After the addition was complete, the cryogenic apparatus was removed, and the reaction was stirred at 60 °C for 2 h. Subsequently, the heating was paused, and after the system was brought back to room temperature, the reaction system was placed at -78 °C. Boron tribromide (0.77 mL, 8.1 mmol) was added dropwise. After the addition was complete, the system was gradually brought back to room temperature. After 30 min, anhydrous N,N-diisopropylethylamine (1.4 mL, 8.1 mmol) was added dropwise to the system under ice-salt bath conditions. The system was then brought back to room temperature and stirred for 30 min, followed by heating to 120 °C and stirring for 12 h. After the reaction was completed and the temperature was brought back to room temperature, the reaction was quenched by adding phosphate buffer solution (pH = 6), the organic phase was collected and distilled under reduced pressure, and further purified by silica gel column chromatography using petroleum ether:dichloromethane (10:1) as eluent to obtain 0.98 g of orange-yellow solid, with a yield of 27.5%.

[0083]

[0084] Preparation of compound 7: Compound 6 (530 mg, 1.10 mmol), pinacol diborate (234 mg, 1.65 mmol), tricyclohexylphosphine (31 mg, 0.11 mmol), and potassium acetate (30.9 mg, 0.11 mmol) were added sequentially to a reaction flask. 1,4-dioxane was used as the reaction solvent. Under nitrogen protection, the reaction was carried out at 100 °C with continuous stirring for 12 h. After the reaction was completed and cooled, the mixture was concentrated under reduced pressure and purified by column chromatography using petroleum ether:dichloromethane (4:1) as the eluent, yielding 412 mg of an orange-yellow solid, with a yield of 62.2%.

[0085]

[0086] Preparation of compound C: Under nitrogen protection, 4-bromo-2-methylisoquinoline-1(2H)-one (372 mg, 1.56 mmol), compound 7 (855 mg, 1.42 mmol), Pd(PPh3)4 (32.8 mg, 28.4 mmol), 2 mol·L⁻¹ potassium carbonate aqueous solution (1.4 mL, 2.84 mmol), and 50 mL of 1,4-dioxane solvent were added sequentially to a reaction flask. After three nitrogen purgings, the mixture was heated to 100 °C and stirred for 12 h. After the reaction was completed and cooled, the solvent was removed by vacuum distillation. The crude product was purified by column chromatography using dichloromethane:petroleum ether (1:3) as the eluent to obtain 0.52 g of an orange-yellow solid, with a yield of 60%.

[0087]

[0088] Example 4: Preparation of Compound D

[0089] Preparation of Compound 5: Under nitrogen protection, phenoxazine (PXZ) (3.20 g, 17.5 mmol) and cesium carbonate (8.55 g, 26.3 mmol) were added sequentially to the reaction flask using ultradry N,N-dimethylformamide as the solvent. The mixture was stirred at room temperature for 30 min. Subsequently, 2-bromo-1,3-difluorobenzene (1.98 g, 8.7 mmol) was added under a nitrogen atmosphere, and the reaction temperature was set at 155 °C. The reaction was stirred continuously for 24 h. Thin-layer chromatography was used to monitor the reaction. After the reaction was terminated and cooled to room temperature, the reaction solution was slowly poured into 200 mL of distilled water and stirred continuously for 30 min. All the white solid precipitated. The crude pale yellow solid collected by vacuum filtration was eluted with petroleum ether and petroleum ether:dichloromethane (6:1) as the developing solvent, and further purified by column chromatography to obtain 4.20 g of pale yellow solid, with a yield of 89.2%.

[0090]

[0091] Preparation of Compound 6: A dry 250 mL three-necked flask was used to add Compound 5 (4.10 g, 7.4 mmol) and 100 mL of anhydrous tert-butylbenzene solvent. The mixture was stirred until dissolved, and the reaction system was protected with nitrogen. At -78 °C, n-butyllithium (5.09 mL, 8.1 mmol, 1.6 M) was added dropwise to the reaction system. After the addition was complete, the cryogenic apparatus was removed, and the reaction was stirred at 60 °C for 2 h. Subsequently, the heating was paused, and after the system was brought back to room temperature, the reaction system was placed at -78 °C. Boron tribromide (0.77 mL, 8.1 mmol) was added dropwise. After the addition was complete, the system was gradually brought back to room temperature. After 30 min, anhydrous N,N-diisopropylethylamine (1.4 mL, 8.1 mmol) was added dropwise to the system under ice-salt bath conditions. The system was then brought back to room temperature and stirred for 30 min, followed by heating to 120 °C and stirring for 12 h. After the reaction was completed and the temperature was brought back to room temperature, the reaction was quenched by adding phosphate buffer solution (pH = 6), the organic phase was collected and distilled under reduced pressure, and further purified by silica gel column chromatography using petroleum ether:dichloromethane (10:1) as eluent to obtain 0.98 g of orange-yellow solid, with a yield of 27.5%.

[0092]

[0093] Preparation of compound 7: Compound 6 (530 mg, 1.10 mmol), pinacol diborate (234 mg, 1.65 mmol), tricyclohexylphosphine (31 mg, 0.11 mmol), and potassium acetate (30.9 mg, 0.11 mmol) were added sequentially to a reaction flask. 1,4-dioxane was used as the reaction solvent. Under nitrogen protection, the reaction was carried out at 100 °C with continuous stirring for 12 h. After the reaction was completed and cooled, the mixture was concentrated under reduced pressure and purified by column chromatography using petroleum ether:dichloromethane (4:1) as the eluent, yielding 412 mg of an orange-yellow solid, with a yield of 62.2%.

[0094]

[0095] Preparation of compound D: Under nitrogen protection, 6-bromo-2-methylisoquinoline-1(2H)-one (372 mg, 1.56 mmol), compound 7 (855 mg, 1.42 mmol), Pd(PPh3)4 (32.8 mg, 28.4 mmol), 2 mol·L⁻¹ potassium carbonate aqueous solution (1.4 mL, 2.84 mmol), and 50 mL of 1,4-dioxane solvent were added sequentially to a reaction flask. After three nitrogen purgings, the mixture was heated to 100 °C and stirred for 12 h. After the reaction was completed and cooled, the solvent was removed by vacuum distillation. The crude product was purified by column chromatography using dichloromethane:petroleum ether (1:3) as the eluent to obtain 0.52 g of orange solid, with a yield of 60%.

[0096]

[0097] Example 5: Preparation of compound E

[0098] Preparation of Compound 8: Under nitrogen protection, dimethylacridine (DMAC) (3.72 g, 17.8 mmol) and cesium carbonate (8.76 g, 26.9 mmol) were added sequentially to the reaction flask using ultradry N,N-dimethylformamide as the solvent. The mixture was stirred at room temperature for 30 min. Subsequently, 2-bromo-1,3-difluorobenzene (2.01 g, 8.9 mmol) was added under a nitrogen atmosphere, and the reaction temperature was set at 155 °C. The reaction was stirred continuously for 24 h. Thin-layer chromatography was used to monitor the reaction. After the reaction was terminated and cooled to room temperature, the reaction solution was slowly poured into 200 mL of distilled water and stirred continuously for 30 min. A white solid precipitated completely. The crude product, a pale yellow solid, was collected by vacuum filtration. It was eluted with petroleum ether and petroleum ether:dichloromethane (8:1) as developing solvents, and further purified by column chromatography to obtain 5.00 g of pale yellow solid, with a yield of 92.7%.

[0099]

[0100] Preparation of Compound 9: A dry 250 mL three-necked flask was used to add Compound 8 (4.50 g, 7.4 mmol) and 100 mL of anhydrous tert-butylbenzene solvent. The mixture was stirred until dissolved, and the reaction system was protected with nitrogen. At -78 °C, n-butyllithium (5.09 mL, 8.1 mmol, 1.6 M) was added dropwise to the reaction system. After the addition was complete, the cryogenic apparatus was removed, and the reaction was stirred at 60 °C for 2 h. Heating was then paused, and after the system was brought back to room temperature, the reaction system was placed at -78 °C. Boron tribromide (0.77 mL, 8.1 mmol) was added dropwise. After the addition was complete, the system was gradually brought back to room temperature. After 30 min, anhydrous N,N-diisopropylethylamine (1.4 mL, 8.1 mmol) was added dropwise to the system under ice-salt bath conditions. The system was then brought back to room temperature and stirred for 30 min, followed by heating to 120 °C and stirring for 12 h. After the reaction was completed and the temperature was brought back to room temperature, the reaction was quenched by adding phosphate buffer solution (pH = 6), the organic phase was collected and distilled under reduced pressure, and further purified by silica gel column chromatography using petroleum ether:dichloromethane (8:1) as eluent to obtain 0.88 g of yellow solid, with a yield of 22.2%.

[0101]

[0102] Preparation of compound 10: Compound 9 (600 mg, 1.12 mmol), pinacol diborate (427 mg, 1.68 mmol), tricyclohexylphosphine (31 mg, 0.11 mmol), and potassium acetate (30.9 mg, 0.11 mmol) were added sequentially to a reaction flask. 1,4-dioxane was used as the reaction solvent. Under nitrogen protection, the reaction was carried out at 100 °C with continuous stirring for 12 h. After the reaction was completed and cooled, the mixture was concentrated under reduced pressure and purified by column chromatography using petroleum ether:dichloromethane (6:1) as the eluent, yielding 508 mg of a yellow solid, with a yield of 69.3%.

[0103]

[0104] Preparation of compound E: Under nitrogen protection, 4-bromo-2-methylisoquinoline-1(2H)-one (196 mg, 0.82 mmol), compound 10 (490 mg, 1.42-0.75 mmol), Pd(PPh3)4 (17.3 mg, 15 mmol), 2 mol·L⁻¹ potassium carbonate aqueous solution (0.75 mL, 1.50 mmol), and 40 mL of 1,4-dioxane solvent were added sequentially to a reaction flask. After three nitrogen purgings, the mixture was heated to 100 °C and stirred for 12 h. After the reaction was completed and cooled, the solvent was removed by vacuum distillation. The crude product was purified by column chromatography using dichloromethane:petroleum ether (1:3) as the eluent to obtain 0.350 g of a yellow solid, with a yield of 71.4%.

[0105]

[0106] Example 6: Preparation of compound F

[0107] Preparation of Compound 8: Under nitrogen protection, dimethylacridine (DMAC) (3.72 g, 17.8 mmol) and cesium carbonate (8.76 g, 26.9 mmol) were added sequentially to the reaction flask using ultradry N,N-dimethylformamide as the solvent. The mixture was stirred at room temperature for 30 min. Subsequently, 2-bromo-1,3-difluorobenzene (2.01 g, 8.9 mmol) was added under a nitrogen atmosphere, and the reaction temperature was set at 155 °C. The reaction was stirred continuously for 24 h. Thin-layer chromatography was used to monitor the reaction. After the reaction was terminated and cooled to room temperature, the reaction solution was slowly poured into 200 mL of distilled water and stirred continuously for 30 min. A white solid precipitated completely. The crude product, a pale yellow solid, was collected by vacuum filtration. It was eluted with petroleum ether and petroleum ether:dichloromethane (8:1) as developing solvents, and further purified by column chromatography to obtain 5.00 g of pale yellow solid, with a yield of 92.7%.

[0108]

[0109] Preparation of Compound 9: A dry 250 mL three-necked flask was used to add Compound 8 (4.50 g, 7.4 mmol) and 100 mL of anhydrous tert-butylbenzene solvent. The mixture was stirred until dissolved, and the reaction system was protected with nitrogen. At -78 °C, n-butyllithium (5.09 mL, 8.1 mmol, 1.6 M) was added dropwise to the reaction system. After the addition was complete, the cryogenic apparatus was removed, and the reaction was stirred at 60 °C for 2 h. Heating was then paused, and after the system was brought back to room temperature, the reaction system was placed at -78 °C. Boron tribromide (0.77 mL, 8.1 mmol) was added dropwise. After the addition was complete, the system was gradually brought back to room temperature. After 30 min, anhydrous N,N-diisopropylethylamine (1.4 mL, 8.1 mmol) was added dropwise to the system under ice-salt bath conditions. The system was then brought back to room temperature and stirred for 30 min, followed by heating to 120 °C and stirring for 12 h. After the reaction was completed and the temperature was brought back to room temperature, the reaction was quenched by adding phosphate buffer solution (pH = 6), the organic phase was collected and distilled under reduced pressure, and further purified by silica gel column chromatography using petroleum ether:dichloromethane (8:1) as eluent to obtain 0.88 g of yellow solid, with a yield of 22.2%.

[0110]

[0111] Preparation of compound 10: Compound 9 (600 mg, 1.12 mmol), pinacol diborate (427 mg, 1.68 mmol), tricyclohexylphosphine (31 mg, 0.11 mmol), and potassium acetate (30.9 mg, 0.11 mmol) were added sequentially to a reaction flask. 1,4-dioxane was used as the reaction solvent. Under nitrogen protection, the reaction was carried out at 100 °C with continuous stirring for 12 h. After the reaction was completed and cooled, the mixture was concentrated under reduced pressure and purified by column chromatography using petroleum ether:dichloromethane (6:1) as the eluent, yielding 508 mg of a yellow solid, with a yield of 69.3%.

[0112]

[0113] Preparation of compound F: Under nitrogen protection, 6-bromo-2-methylisoquinoline-1(2H)-one (196 mg, 0.82 mmol), compound 10 (490 mg, 1.42-0.75 mmol), Pd(PPh3)4 (17.3 mg, 15 mmol), 2 mol·L⁻¹ potassium carbonate aqueous solution (0.75 mL, 1.50 mmol), and 40 mL of 1,4-dioxane solvent were added sequentially to a reaction flask. After three nitrogen purgings, the mixture was heated to 100 °C and stirred for 12 h. After the reaction was completed and cooled, the solvent was removed by vacuum distillation. The crude product was purified by column chromatography using dichloromethane:petroleum ether (1:3) as the eluent to obtain 0.350 g of a yellow solid, with a yield of 71.4%.

[0114]

[0115] See Figure 1-6 The boron-nitroisoquinolinone A compound exhibits characteristic absorption peaks at 282 nm and 472 nm, with an emission wavelength of 496 nm. The maximum half-width at half-maximum (FWHM) of the emission spectrum is only 29 nm, demonstrating a significantly narrow spectral band. Fluorescence quantum yield (PLQY) measurements show that this material reaches 84%. Time-resolved spectroscopy analysis reveals that the material possesses both instantaneous and delayed fluorescence lifetimes, thus elucidating its thermally activated delayed fluorescence (TADF) characteristics. Thermogravimetric analysis (TGA) results, used to assess the material's thermal stability, show that its thermal decomposition temperature exceeds 400 °C. Based on these properties, this material has potential applications in organic light-emitting diodes (OLEDs).

[0116] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0117] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A boron-nitroisoquinoline ketone derivative, characterized in that: Its general structural formula is as follows: ， R1 is boraxazole, boraxphenoxazine, boraxdimethylacidine, o-benzazole, m-benzazole, p-benzazole, or triphenylamine, and the linking site between R1 and the isoquinolinone core is at position 4 or 6 of the isoquinolinone structure.

2. The boron-nitroisoquinoline ketone derivative according to claim 1, characterized in that: R1 is set to any of the following ac: 。 3. The boron-nitroisoquinoline ketone derivative according to claim 1, characterized in that: The derivative is any one of the following compounds A through F: 。 4. A method for preparing a boron-nitroisoquinoline ketone derivative according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Under nitrogen protection, using ultra-dry N,N-dimethylformamide as solvent, 3,6-di-tert-butylcarbazole, phenoxazine or dimethylacridine is mixed with cesium carbonate, stirred at room temperature, and then 2-bromo-1,3-difluorobenzene is added. After post-treatment, intermediate 1 is obtained. Step 2: Under nitrogen protection, intermediate 1 is dissolved in anhydrous tert-butylbenzene, and n-butyllithium, boron tribromide and N,N-diisopropylethylamine are added in sequence, and intermediate 2 is obtained by cyclization reaction; Step 3: Under ice bath conditions, using N,N-dimethylformamide as the reaction solvent, intermediate 2 and an equimolar amount of N-bromosuccinimide were reacted in N,N-dimethylformamide at room temperature, and after post-treatment, intermediate 3 was obtained. Step 4: Under nitrogen protection, using tetrahydrofuran as the reaction solvent, intermediate 3 is reacted with n-butyllithium and trimethyl borate to obtain intermediate 4; Step 5: Under nitrogen protection, intermediate 4 obtained in step 4 is coupled with 4-bromo-2-methylisoquinoline-1(2H)-one or 6-bromo-2-methylisoquinoline-1(2H)-one in the presence of Pd(PPh3)4 and potassium carbonate in a mixed solvent of toluene and ethanol or 1,4-dioxane to obtain the target product.

5. The method for preparing a boron-nitroisoquinoline ketone derivative according to claim 4, characterized in that: The reaction temperature in step 1 is 155°C and the reaction time is 24 hours.

6. The method for preparing a boron-nitroisoquinoline ketone derivative according to claim 4, characterized in that: The cyclization reaction described in step 2 includes: adding n-butyllithium at -78°C, heating to 60°C and reacting for 2 hours, then cooling to -78°C and adding boron tribromide, restoring to room temperature and adding N,N-diisopropylethylamine, and finally heating to 120°C and reacting for 12 hours.

7. The method for preparing a boron-nitroisoquinoline ketone derivative according to claim 4, characterized in that: In step 4, the molar ratio of n-butyllithium to intermediate 3 is 1.5:1, and the molar ratio of trimethyl borate to intermediate 3 is 2:

1. The reaction is carried out by adding n-butyllithium at -78°C, followed by adding trimethyl borate and heating the reaction for 12 hours.

8. The method for preparing a boron-nitroisoquinoline ketone derivative according to claim 4, characterized in that: Another way to prepare borate intermediate 4 in step 4 is to react intermediate 2 with pinacol diboronate, tricyclohexylphosphine, and potassium acetate in 1,4-dioxane at 100°C for 12 hours.

9. The method for preparing a boron-nitroisoquinoline ketone derivative according to claim 4, characterized in that: The reaction temperature of the Suzuki coupling reaction in step 5 is 80-100℃, and the reaction time is 12 hours.

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