A boron-containing fused-ring carbene iridium and platinum complex and its preparation method and application

Abstract

The present invention discloses a boron-containing fused-ring carbene iridium-platinum complex, its preparation method, and its application in the preparation of organic electronic devices, particularly organic light-emitting diodes. The present invention also relates to organic electronic devices, particularly organic light-emitting diodes, containing the boron-containing fused-ring carbene iridium-platinum complex, and their applications in display and lighting technologies. By optimizing the device structure and varying the concentration of the boron-containing fused-ring carbene iridium-platinum complex in the matrix, the present invention achieves optimal device performance, facilitates the realization of high-efficiency, high-brightness, and highly stable OLED devices, and provides a superior material option for full-color display and lighting applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and specifically relates to a boron-containing fused-ring carbene iridium and platinum complex, a preparation method and application thereof, and especially relates to application in organic light-emitting diodes. Background Art

[0002] Organic light-emitting diodes (OLEDs) hold great potential for applications in optoelectronic devices such as flat-panel displays and lighting, owing to the synthetic diversity, relatively low manufacturing costs, and excellent optical and electrical properties of organic semiconductor materials. To improve the luminous efficiency of OLEDs, various fluorescent and phosphorescent luminescent material systems have been developed. While OLEDs using fluorescent materials offer high reliability, their internal electroluminescence quantum efficiency (EL) is limited to 25% under electric field excitation due to a 1:3 probability ratio between singlet and triplet excited states. In 1999, Professors Thomson of the University of Southern California and Forrest of Princeton University successfully fabricated green electrophosphorescent devices by doping tris(2-phenylpyridine)iridium (Ir(ppy)3) into N,N-dicarbazolebiphenyl (CBP), sparking significant interest in complex phosphorescent materials. The introduction of heavy metals improves molecular spin-orbit coupling, shortens the phosphorescence lifetime, enhances molecular intersystem crossing, and enables smooth phosphorescence emission. To date, the internal quantum efficiency of phosphorescent OLEDs has reached nearly 100%.

[0003] Despite this, most phosphorescent iridium and platinum complexes still suffer from excessively wide emission peak half-widths, and some also suffer from low luminous efficiency and poor stability, which to some extent affect the luminescent properties of the complexes. Currently, carbene ligands with strong field effects can, to a certain extent, address these stability and luminous efficiency issues of phosphorescent complexes. At the same time, rigid boron-containing fused ring units can also, to a certain extent, reduce the emission half-widths of phosphorescent complexes. Therefore, in order to further improve the luminescent properties of phosphorescent iridium and platinum complexes and broaden the selection range of such materials, materials based on boron-containing fused ring carbene iridium and platinum complexes are urgently needed. Summary of the Invention

[0004] Purpose of the invention: In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a new type of boron-containing fused-ring carbene iridium and platinum complex with high stability and strong luminescence efficiency.

[0005] The technical problem that the present invention also aims to solve is to provide a method for preparing a boron-containing fused-ring carbene iridium and platinum complex.

[0006] The technical problem that the present invention also aims to solve is to provide an application of a boron-containing fused-ring carbene iridium and platinum complex in the preparation of organic electronic devices.

[0007] The final technical problem to be solved by the present invention is to provide an OLED device with high efficiency, high brightness and high stability.

[0008] Technical solution: In order to solve the above technical problems, the present invention provides a boron-containing fused-ring carbene iridium and platinum complex, the general formula of which is shown in the structure (AH):

[0009]

[0010] Wherein, X is an O atom or an S atom, and R is a H atom or a tert-butyl group.

[0011] Among them, the boron-containing fused-ring carbene iridium and platinum complexes M1-M40:

[0012]

[0013]

[0014]

[0015]

[0016] The present invention also includes a method for preparing the boron-containing fused-ring carbene iridium and platinum complex, comprising the following steps:

[0017] 1) First, 2,5-dibromo-1,3-difluorobenzene is reacted with phenol and its derivatives or thiophenol and its derivatives in an alkaline and high-temperature environment to undergo a fluorine substitution reaction to obtain the first-step precursor (1a-4a). This is then reacted with imidazole or benzimidazole in the presence of alkali and cuprous iodide to obtain the corresponding second-step precursor (1b-8b).

[0018] 2) The precursor (1b-8b) prepared in step 1) is then subjected to further bromine removal using n-butyl lithium n-BuLi in a dry m-xylene solution under anhydrous, oxygen-free, and low-temperature conditions. Boron tribromide is then added and reacted with stirring. Finally, in the alkaline environment of N,N-diisopropylethylamine, by controlling the reaction temperature and time, a series of boron-containing fused ring intermediate compounds (1c-8c) can be obtained. These compounds are then methylated using iodomethane to form a series of novel boron-containing fused ring imidazolium or benzimidazole ligands (1d-8d).

[0019] 3) Finally, the boron-containing fused-ring imidazole salt or benzimidazole salt ligand (1d-8d) prepared in step 2) is used to carry out coordination reaction with metal iridium and platinum respectively to obtain a series of boron-containing fused-ring carbene iridium and platinum complexes.

[0020] The present invention also includes the use of the boron-containing fused-ring carbene iridium and platinum complex in the preparation of organic electronic devices.

[0021] Among them, the organic electronic devices are organic light emitting diodes (OLEDs), organic photovoltaic cells (OPVs), organic light emitting cells (OLEECs), organic field effect transistors (OFETs), organic light emitting field effect transistors, organic lasers, organic spintronic devices, organic sensors and organic plasmon emitting diodes (Organic Plasmon Emitting Diodes).

[0022] The mass concentration of the boron-containing fused-ring carbene iridium and platinum complex in the matrix is ​​1-15 wt %.

[0023] The present invention also includes an organic electronic device comprising the boron-containing fused-ring carbene iridium and platinum complex.

[0024] The mass concentration of the boron-containing fused-ring carbene iridium and platinum complex is 1-15 wt%.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following advantages: the ligands contained in the novel phosphorescent iridium and platinum complexes prepared by the present invention, on the one hand, have a carbene coordination unit with a strong field effect, thereby effectively improving the stability and luminescence efficiency of the compound; on the other hand, they also have a rigid boron-containing fused ring unit, which can further reduce the emission half-peak width of the complex, thereby improving the luminescence performance and the performance of the corresponding device. The present invention also relates to organic electronic devices, especially organic light-emitting diodes, containing the boron-containing fused ring carbene iridium and platinum complexes according to the present invention, and their applications in display and lighting technology. By optimizing the device structure and changing the concentration of the boron-containing fused ring carbene iridium and platinum complex in the matrix, optimal device performance can be achieved, facilitating the realization of high-efficiency, high-brightness, and high-stability OLED devices, and providing a better material option for full-color display and lighting applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 X-ray single crystal structure of boron-containing fused-ring carbene iridium complex M5;

[0027] Figure 2 X-ray single crystal structure of boron-containing fused-ring carbene iridium complex M9;

[0028] Figure 3 X-ray single crystal structure of boron-containing fused-ring carbene iridium complex M13;

[0029] Figure 4 X-ray single crystal structure of boron-containing fused-ring carbene iridium complex M17;

[0030] Figure 5X-ray single crystal structure of boron-containing fused-ring carbene iridium complex M21. DETAILED DESCRIPTION

[0031] Example 1 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M1

[0032] Synthesis route of boron-containing fused-ring carbene iridium complex M1:

[0033]

[0034] 1. Synthesis of intermediate 1a:

[0035] Phenol (10.39 g, 110.53 mmol), 2,5-dibromo-1,3-difluorobenzene (9.97 g, 36.80 mmol), and potassium carbonate (15.30 g, 110.70 mmol) were placed in a dry two-necked flask and evacuated and filled with nitrogen three times. N-methylpyrrolidone (NMP) (55 mL) was added under a nitrogen stream. The reaction was stirred at 170°C for 24 hours. After cooling to room temperature, the NMP solvent was removed by rotary evaporation, and a large amount of water was added. The product was extracted three times with ethyl acetate. The organic phases were combined and concentrated, and then purified on a silica gel column using dichloromethane:petroleum ether = 1:10 to obtain 13.22 g of a white solid, intermediate 1a, with a yield of 86%. MALDI-TOF-MS (m / z) 421.1 ([M+1] + ).

[0036] 2. Synthesis of intermediate 1b:

[0037] In a dry Schlenck bottle, intermediate 1a (5.0 g, 11.9 mmol), imidazole (1.44 g, 21.2 mmol), CuI (1.0 g, 5.25 mmol), and potassium carbonate (3.0 g, 21.7 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Then, 70 mL of dry DMF was added under a nitrogen stream and the reaction was stirred at 150°C for 12 hours. After cooling to room temperature, the DMF was evaporated under reduced pressure. A large amount of water was then added and the mixture was extracted three times with dichloromethane. The organic phases were combined, concentrated, and then filtered through a silica gel column with ethyl acetate:petroleum ether = 1:1 to obtain 2.42 g of a white solid, intermediate 1b, with a yield of 50%. MALDI-TOF-MS (m / z): 408.3 ([M+1] + ).

[0038] 3. Synthesis of intermediate 1c:

[0039] Intermediate 1b (1.19 g, 2.92 mmol) was added to a dry 100 mL Schlenck tube and evacuated and refilled with nitrogen three times. Dry m-xylene (25 mL) was then added under a nitrogen atmosphere. n-Butyl lithium (1.30 mL, 3.21 mmol) was added at 0°C, and the reaction was stirred at 0°C for 20 minutes. The mixture was then brought to room temperature and stirred for 1 hour. The temperature was then lowered to 0°C, and boron tribromide (0.50 mL, 5.25 mmol) was added. The mixture was stirred at 0°C for 20 minutes, and then brought to room temperature and stirred for 30 minutes. The mixture was then heated to 45°C and stirred for 50 minutes. The temperature was then lowered again to 0°C, and N,N-diisopropylethylamine (1.00 mL, 5.84 mmol) was added. Finally, the mixture was heated to 140°C and stirred for 12 hours. After the reaction was completed, the mixture was cooled to room temperature and the resulting solution was washed with a saturated sodium acetate solution. A large amount of water and dichloromethane solution were then added, followed by extraction three times. The combined organic phases were concentrated by rotary evaporation and dried to obtain approximately 0.83 g of a light yellow solid, intermediate 1c, with a yield of 85%. MALDI-TOF-MS (m / z): 337.2 ([M+1] + ).

[0040] 4. Synthesis of intermediate 1d:

[0041] Intermediate 1c (0.67 g, 2 mmol) was placed in a dry Schlenck flask and evacuated and refilled with nitrogen three times. Then, 20 mL of dry tetrahydrofuran was added under a nitrogen stream and stirred at room temperature for ten minutes. Iodomethane (0.50 mL, 8 mmol) was then added and the mixture was heated to 65°C with stirring for three days. After the reaction, the mixture was cooled to room temperature and the filter cake was filtered and rinsed with tetrahydrofuran to obtain 0.38 g of a white solid, Intermediate 1d, with a yield of 40%. ESI-MS (m / z): 351.3 ([MI] + ).

[0042] 5. Synthesis of boron-containing fused-ring carbene iridium complex M1:

[0043] In a dry Schlenck bottle, intermediate 1d (0.136 g, 0.285 mmol), Ag2O (0.066 g, 0.285 mmol), and [Ir(COD)Cl]2 (0.039 g, 0.057 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. Triethylamine (0.04 mL, 0.285 mmol) and chlorobenzene (20 mL) were then added under a nitrogen stream. The reaction was stirred at 120°C for 24 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure. The mixture was then filtered through a silica gel column using dichloromethane:petroleum ether (1:1) to obtain 42 mg of a yellow solid, the boron-containing fused-ring carbene iridium complex M1, in a 30% yield. MALDI-TOF-MS (m / z): 1239.5 ([M] + ).

[0044] Example 2 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M2

[0045] Synthesis route of boron-containing fused-ring carbene iridium complex M2:

[0046]

[0047] 1. Synthesis of intermediate 2a:

[0048] In a dry two-necked flask, p-tert-butylphenol (16.58 g, 110.53 mmol), 2,5-dibromo-1,3-difluorobenzene (9.97 g, 36.80 mmol), and potassium carbonate (15.30 g, 110.70 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. N-methylpyrrolidone (NMP) (55 mL) was added under a nitrogen stream. The reaction was stirred at 170°C for 24 hours. After cooling to room temperature, the NMP solvent was removed by rotary evaporation. A large amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were combined and concentrated, and then purified on a silica gel column using dichloromethane:petroleum ether (1:10) to obtain 15.66 g of a white solid, intermediate 2a, with a yield of 80%. MALDI-TOF-MS (m / z): 532.4 ([M] + ).

[0049] 2. Synthesis of intermediate 2b:

[0050] In a dry Schlenck flask, intermediate 2a (6.3 g, 11.9 mmol), imidazole (1.44 g, 21.2 mmol), CuI (1.0 g, 5.25 mmol), and potassium carbonate (3.0 g, 21.7 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. Then, 70 mL of dry DMF was added under a nitrogen stream and the reaction was stirred at 150°C for 12 hours. After cooling to room temperature, the DMF was evaporated under reduced pressure. A large amount of water was added and the mixture was extracted three times with dichloromethane. The organic phases were combined, concentrated, and then filtered through a silica gel column with ethyl acetate:petroleum ether (1:1) to obtain 2.78 g of a white solid, intermediate 2b, in a 45% yield. MALDI-TOF-MS (m / z): 520.3 ([M+1] + ).

[0051] 3. Synthesis of intermediate 2c:

[0052] Intermediate 2b (1.52 g, 2.92 mmol) was added to a dry 100 mL Schlenck tube and evacuated and refilled with nitrogen three times. Dry m-xylene (25 mL) was then added under a nitrogen atmosphere. n-Butyl lithium (1.30 mL, 3.21 mmol) was added at 0°C, and the reaction was stirred at 0°C for 20 minutes. The mixture was then brought to room temperature and stirred for 1 hour. The temperature was then lowered to 0°C, and boron tribromide (0.50 mL, 5.25 mmol) was added. The mixture was stirred at 0°C for 20 minutes, and then brought to room temperature and stirred for 30 minutes. The mixture was then heated to 45°C and stirred for 50 minutes. The temperature was then lowered again to 0°C, and N,N-diisopropylethylamine (1.00 mL, 5.84 mmol) was added. Finally, the mixture was heated to 140°C and stirred for 12 hours. After the reaction was complete, the solution was cooled to room temperature and washed with saturated sodium acetate solution, then extracted several times with water and dichloromethane. The combined organic phases were concentrated by rotary evaporation and dried to obtain approximately 1.05 g of a pale yellow solid, intermediate 2c, with a yield of 80%. MALDI-TOF-MS (m / z): 449.2 ([M+1] + ).

[0053] 4. Synthesis of intermediate 2d:

[0054] Intermediate 2c (0.90 g, 2 mmol) was placed in a dry Schlenck flask and evacuated and refilled with nitrogen three times. Then, 20 mL of dry tetrahydrofuran was added under a nitrogen stream and stirred at room temperature for ten minutes. Iodomethane (0.50 mL, 8 mmol) was then added and the temperature was raised to 65°C with stirring for three days. After the reaction, the flask was cooled to room temperature and the filter cake was filtered and rinsed with tetrahydrofuran to obtain 0.49 g of a white solid, intermediate 2d, with a yield of 42%. ESI-MS (m / z): 463.2 ([MI] + ).

[0055] 5. Synthesis of boron-containing fused-ring carbene iridium complex M2:

[0056] In a dry Schlenck bottle, 2d (0.168 g, 0.285 mmol), Ag2O (0.066 g, 0.285 mmol), and [Ir(COD)Cl]2 (0.039 g, 0.057 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. Then, triethylamine (0.04 mL, 0.285 mmol) and chlorobenzene (20 mL) were added under a nitrogen stream. The reaction was stirred at 120°C for 24 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure. The mixture was then filtered through a silica gel column using dichloromethane:petroleum ether (1:1) to obtain 45 mg of a yellow solid, the boron-containing fused-ring carbene iridium complex M2, in a 25% yield. MALDI-TOF-MS (m / z): 1576.5 ([M] + ).

[0057] Example 3 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M3

[0058] Synthesis route of boron-containing fused-ring carbene iridium complex M3:

[0059]

[0060] 1. Synthesis of intermediate 3a:

[0061] Sodium thiophenolate (14.59 g, 110.53 mmol) and 2,5-dibromo-1,3-difluorobenzene (9.97 g, 36.80 mmol) were placed in a dry two-necked flask and evacuated and filled with nitrogen for three cycles. N-methylpyrrolidone (NMP) (55 mL) was added under a nitrogen stream. The reaction was stirred at 170°C for 24 hours. After cooling to room temperature, the NMP solvent was removed by rotary evaporation, a large amount of water was added, and the product was extracted three times with ethyl acetate. The organic phases were combined and concentrated, and purified on a silica gel column using dichloromethane:petroleum ether = 1:10 to obtain 13.81 g of a white solid, intermediate 3a, with a yield of 83%. MALDI-TOF-MS (m / z): 452.2 ([M] + ).

[0062] 2. Synthesis of intermediate 3b:

[0063] In a dry Schlenck bottle, intermediate 3a (5.38 g, 11.9 mmol), imidazole (1.44 g, 21.2 mmol), CuI (1.0 g, 5.25 mmol), and potassium carbonate (3.0 g, 21.7 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. Then, 70 mL of dry DMF was added under a nitrogen stream and the reaction was stirred at 150°C for 12 hours. After cooling to room temperature, the DMF was evaporated under reduced pressure. A large amount of water was added and the mixture was extracted three times with dichloromethane. The organic phases were combined, concentrated, and then filtered through a silica gel column with ethyl acetate:petroleum ether (1:1) to obtain 2.19 g of a yellow solid, intermediate 3b, in a 42% yield. MALDI-TOF-MS (m / z): 440.1 ([M+1] + ).

[0064] 3. Synthesis of intermediate 3c:

[0065] Intermediate 3b (1.28 g, 2.92 mmol) was added to a dry 100 mL Schlenck tube and evacuated and refilled with nitrogen three times. Dry m-xylene (25 mL) was then added under a nitrogen atmosphere. n-Butyl lithium (1.30 mL, 3.21 mmol) was added at 0°C, and the reaction was stirred at 0°C for 20 minutes. The mixture was then brought to room temperature and stirred for 1 hour. The temperature was then lowered to 0°C, and boron tribromide (0.50 mL, 5.25 mmol) was added. The mixture was stirred at 0°C for 20 minutes, and then brought to room temperature and stirred for 30 minutes. The mixture was then heated to 45°C and stirred for 50 minutes. The temperature was then lowered again to 0°C, and N,N-diisopropylethylamine (1.00 mL, 5.84 mmol) was added. Finally, the mixture was heated to 140°C and stirred for 12 hours. After the reaction was complete, the solution was cooled to room temperature and washed with saturated sodium acetate solution, then extracted several times with water and dichloromethane. The combined organic phases were concentrated by rotary evaporation and dried to obtain approximately 0.91 g of a yellow solid, intermediate 3c, with a yield of 85%. MALDI-TOF-MS (m / z): 369.3 ([M+1] + ).

[0066] 4. Synthesis of intermediate 3d:

[0067] Intermediate 3c (0.74 g, 2 mmol) was placed in a dry Schlenck flask and evacuated and refilled with nitrogen three times. Then, 20 mL of dry tetrahydrofuran was added under a nitrogen stream and stirred at room temperature for ten minutes. Iodomethane (0.50 mL, 8 mmol) was then added and the temperature was raised to 65°C with stirring for three days. After the reaction, the flask was cooled to room temperature and the filter cake was filtered and rinsed with tetrahydrofuran to obtain 0.46 g of a yellow solid, intermediate 3d, in a 45% yield. ESI-MS (m / z): 383.3 ([MI] + ).

[0068] 5. Synthesis of boron-containing fused-ring carbene iridium complex M3:

[0069] In a dry Schlenck bottle, intermediate 3d (0.145 g, 0.285 mmol), Ag2O (0.066 g, 0.285 mmol), and [Ir(COD)Cl]2 (0.039 g, 0.057 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. Triethylamine (0.04 mL, 0.285 mmol) and chlorobenzene (20 mL) were then added under a nitrogen stream. The reaction was stirred at 120°C for 24 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure. The mixture was then filtered through a silica gel column using dichloromethane:petroleum ether (1:1) to obtain 35 mg of a yellow solid, the boron-containing fused-ring carbene iridium complex M3, in a 23% yield. MALDI-TOF-MS (m / z): 1336.3 ([M] + ).

[0070] Example 4 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M4

[0071] Synthesis route of boron-containing fused-ring carbene iridium complex M4:

[0072]

[0073] 1. Synthesis of intermediate 4a:

[0074] In a dry two-necked flask, p-tert-butylthiophenol (18.35 g, 110.53 mmol), 2,5-dibromo-1,3-difluorobenzene (9.97 g, 36.80 mmol), and potassium carbonate (15.30 g, 110.70 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. N-methylpyrrolidone (NMP) (55 mL) was added under a nitrogen stream. The reaction was stirred at 170°C for 24 hours. After cooling to room temperature, the NMP solvent was removed by rotary evaporation. A large amount of water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were combined and concentrated, and then purified on a silica gel column using dichloromethane:petroleum ether (1:10) to obtain 17.23 g of a yellow solid, intermediate 4a, with a yield of 83%. MALDI-TOF-MS (m / z): 564.6 ([M]+ ).

[0075] 2. Synthesis of intermediate 4b:

[0076] In a dry Schlenck bottle, intermediate 4a (6.71 g, 11.9 mmol), imidazole (1.44 g, 21.2 mmol), CuI (1.0 g, 5.25 mmol), and potassium carbonate (3.0 g, 21.7 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Then, 70 mL of dry DMF was added under a nitrogen stream and the reaction was stirred at 150°C for 12 hours. After cooling to room temperature, the DMF was evaporated under reduced pressure. A large amount of water was then added and the mixture was extracted three times with dichloromethane. The organic phases were combined, concentrated, and then filtered through a silica gel column with ethyl acetate:petroleum ether in a ratio of 1:1 to obtain 2.62 g of a yellow solid, intermediate 4b, with a yield of 40%. MALDI-TOF-MS (m / z): 552.7 ([M+1] + ).

[0077] 3. Synthesis of intermediate 4c:

[0078] Intermediate 4b (1.61 g, 2.92 mmol) was added to a dry 100 mL Schlenck tube and evacuated and refilled with nitrogen three times. Dry m-xylene (25 mL) was then added under a nitrogen atmosphere. n-Butyl lithium (1.30 mL, 3.21 mmol) was added at 0°C, and the reaction was stirred at 0°C for 20 minutes. The mixture was then brought to room temperature and stirred for 1 hour. The temperature was then lowered to 0°C, and boron tribromide (0.50 mL, 5.25 mmol) was added. The mixture was stirred at 0°C for 20 minutes, and then brought to room temperature and stirred for 30 minutes. The mixture was then heated to 45°C and stirred for 50 minutes. The temperature was then lowered again to 0°C, and N,N-diisopropylethylamine (1.00 mL, 5.84 mmol) was added. Finally, the mixture was heated to 140°C and stirred for 12 hours. After the reaction was completed, the solution was cooled to room temperature and washed with saturated sodium acetate solution, followed by extraction with water and dichloromethane several times. The combined organic phases were concentrated by rotary evaporation and dried to obtain approximately 1.05 g of a yellow solid, intermediate 4c, with a yield of 75%. MALDI-TOF-MS (m / z): 481.3 ([M+1] + ).

[0079] 4. Synthesis of intermediate 4d:

[0080] Intermediate 4c (0.96 g, 2 mmol) was placed in a dry Schlenck flask and evacuated and refilled with nitrogen three times. Then, 20 mL of dry tetrahydrofuran was added under a nitrogen stream and stirred at room temperature for ten minutes. Iodomethane (0.50 mL, 8 mmol) was then added and the temperature was raised to 65°C with stirring for three days. After the reaction, the flask was cooled to room temperature and the filter cake was filtered and rinsed with tetrahydrofuran to obtain 0.62 g of a yellow solid, intermediate 4d, with a yield of 50%. ESI-MS (m / z): 495.4 ([MI] + ).

[0081] 5. Synthesis of boron-containing fused-ring carbene iridium complex M4:

[0082] In a dry Schlenck bottle, intermediate 4d (0.177 g, 0.285 mmol), Ag2O (0.066 g, 0.285 mmol), and [Ir(COD)Cl]2 (0.039 g, 0.057 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. Triethylamine (0.04 mL, 0.285 mmol) and chlorobenzene (20 mL) were then added under a nitrogen stream. The reaction was stirred at 120°C for 24 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure. The mixture was then filtered through a silica gel column using dichloromethane:petroleum ether (1:1) to obtain 57 mg of a yellow solid, the boron-containing fused-ring carbene iridium complex M4, in a 30% yield. MALDI-TOF-MS (m / z): 1672.8 ([M] + ).

[0083] Example 5 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M5

[0084] Synthesis route of boron-containing fused-ring carbene iridium complex M5:

[0085]

[0086] 1. Synthesis of intermediate 5b:

[0087] In a dry Schlenck flask, intermediate 1a (5.0 g, 11.9 mmol), benzimidazole (2.50 g, 21.2 mmol), CuI (1.0 g, 5.25 mmol), and potassium carbonate (3.0 g, 21.7 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Then, 70 mL of dry DMF was added under a nitrogen stream and the reaction was stirred at 150°C for 12 hours. After cooling to room temperature, the DMF was evaporated under reduced pressure. A large amount of water was then added and the mixture was extracted three times with dichloromethane. The organic phases were combined, concentrated, and then filtered through a column with ethyl acetate:petroleum ether in a ratio of 1:1 to obtain 3.26 g of a white solid, intermediate 5b, with a yield of 60%. MALDI-TOF-MS (m / z): 458.2 ([M+1]+ ).

[0088] 2. Synthesis of intermediate 5c:

[0089] Intermediate 5b (1.33 g, 2.92 mmol) was added to a dry 100 mL Schlenck tube and evacuated and refilled with nitrogen three times. Dry m-xylene (25 mL) was then added under a nitrogen atmosphere. n-Butyl lithium (1.30 mL, 3.21 mmol) was added at 0°C, and the reaction was stirred at 0°C for 20 minutes. The mixture was then brought to room temperature and stirred for 1 hour. The temperature was then lowered to 0°C, and boron tribromide (0.50 mL, 5.25 mmol) was added. The mixture was stirred at 0°C for 20 minutes, and then brought to room temperature and stirred for 30 minutes. The mixture was then heated to 45°C and stirred for 50 minutes. The temperature was then lowered again to 0°C, and N,N-diisopropylethylamine (1.00 mL, 5.84 mmol) was added. Finally, the mixture was heated to 140°C and stirred for 12 hours. After the reaction was completed, the solution was cooled to room temperature and washed with saturated sodium acetate solution, followed by extraction with water and dichloromethane several times. The combined organic phases were concentrated by rotary evaporation and dried to obtain approximately 1.01 g of a pale yellow solid, intermediate 5c, with a yield of 90%. MALDI-TOF-MS (m / z): 387.3 ([M+1] + ).

[0090] 3. Synthesis of intermediate 5d:

[0091] Intermediate 5c (0.77 g, 2 mmol) was placed in a dry Schlenck flask and evacuated and refilled with nitrogen three times. Then, 20 mL of dry tetrahydrofuran was added under a nitrogen stream and stirred at room temperature for ten minutes. Iodomethane (0.50 mL, 8 mmol) was then added and the temperature was raised to 65°C with stirring for three days. After the reaction, the flask was cooled to room temperature and the filter cake was filtered and rinsed with tetrahydrofuran to obtain 0.48 g of a white solid, Intermediate 5d, with a yield of 45%. ESI-MS (m / z): 401.3 ([MI] + ).

[0092] 4. Synthesis of boron-containing fused-ring carbene iridium complex M5:

[0093] In a dry Schlenck bottle, intermediate 5d (0.15 g, 0.285 mmol), Ag2O (0.066 g, 0.285 mmol), and [Ir(COD)Cl]2 (0.039 g, 0.057 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Then, triethylamine (0.04 mL, 0.285 mmol) and chlorobenzene (20 mL) were added under a nitrogen stream and stirred at 120°C for 24 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure, and the mixture was then filtered through a silica gel column with dichloromethane:petroleum ether = 1:1 to obtain 55 mg of a yellow solid with a yield of 35%. MALDI-TOF-MS (m / z): 1389.7 ([M] + ). The X-ray single crystal structure of M5 is shown in Figure 1 .

[0094] Example 6 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M6

[0095] Synthesis route of boron-containing fused-ring carbene iridium complex M6:

[0096]

[0097] 1. Synthesis of intermediate 6b:

[0098] In a dry Schlenck flask, intermediate 2a (6.3 g, 11.9 mmol), benzimidazole (2.50 g, 21.2 mmol), CuI (1.0 g, 5.25 mmol), and potassium carbonate (3.0 g, 21.7 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Then, 70 mL of dry DMF was added under a nitrogen stream and the reaction was stirred at 150°C for 12 hours. After cooling to room temperature, the DMF was evaporated under reduced pressure. A large amount of water was then added and the mixture was extracted three times with dichloromethane. The organic phases were combined, concentrated, and then filtered through a silica gel column with ethyl acetate:petroleum ether in a ratio of 1:1 to obtain 3.72 g of a white solid, intermediate 6b, with a yield of 55%. MALDI-TOF-MS (m / z): 569.3 ([M] + ).

[0099] 2. Synthesis of intermediate 6c:

[0100] Intermediate 6b (1.66 g, 2.92 mmol) was added to a dry 100 mL Schlenck tube and evacuated and refilled with nitrogen three times. Dry m-xylene (25 mL) was then added under a nitrogen atmosphere. n-Butyl lithium (1.30 mL, 3.21 mmol) was added at 0°C, and the reaction was stirred at 0°C for 20 minutes. The mixture was then brought to room temperature and stirred for 1 hour. The temperature was then lowered to 0°C, and boron tribromide (0.50 mL, 5.25 mmol) was added. The mixture was stirred at 0°C for 20 minutes, and then brought to room temperature and stirred for 30 minutes. The mixture was then heated to 45°C and stirred for 50 minutes. The temperature was then lowered again to 0°C, and N,N-diisopropylethylamine (1.00 mL, 5.84 mmol) was added. Finally, the mixture was heated to 140°C and stirred for 12 hours. After the reaction was complete, the solution was cooled to room temperature and washed with saturated sodium acetate solution, then extracted several times with water and dichloromethane. The combined organic phases were concentrated by rotary evaporation and dried to obtain approximately 1.25 g of a pale yellow solid, intermediate 6c, with a yield of 86%. MALDI-TOF-MS (m / z): 499.4 ([M+1] + ).

[0101] 3. Synthesis of intermediate 6d:

[0102] Intermediate 6c (0.99 g, 2 mmol) was placed in a dry Schlenck flask and evacuated and refilled with nitrogen three times. Then, 20 mL of dry tetrahydrofuran was added under a nitrogen stream and stirred at room temperature for ten minutes. Iodomethane (0.50 mL, 8 mmol) was then added and the temperature was raised to 65°C with stirring for three days. After the reaction, the flask was cooled to room temperature and the filter cake was filtered and rinsed with tetrahydrofuran to obtain Intermediate 6d, a white solid (0.59 g) with a yield of 46%. ESI-MS (m / z): 513.5 ([MI] + ).

[0103] 4. Synthesis of boron-containing fused-ring carbene iridium complex M6:

[0104] In a dry Schlenck bottle, intermediate 6d (0.182 g, 0.285 mmol), Ag2O (0.066 g, 0.285 mmol), and [Ir(COD)Cl]2 (0.039 g, 0.057 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Then, triethylamine (0.04 mL, 0.285 mmol) and chlorobenzene (20 mL) were added under a nitrogen stream and stirred at 120°C for 24 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure. The mixture was then filtered through a silica gel column with dichloromethane:petroleum ether = 1:1 to obtain 55 mg of a yellow solid, namely, boron-containing fused-ring carbene iridium complex M6, with a yield of 28%. MALDI-TOF-MS (m / z): 1727.5 ([M+1] + ).

[0105] Example 7 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M7

[0106] Synthesis route of boron-containing fused-ring carbene iridium complex M7:

[0107]

[0108] 1. Synthesis of intermediate 7b:

[0109] In a dry Schlenck flask, intermediate 3a (5.38 g, 11.9 mmol), benzimidazole (2.50 g, 21.2 mmol), CuI (1.0 g, 5.25 mmol), and potassium carbonate (3.0 g, 21.7 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. Then, 70 mL of dry DMF was added under a nitrogen stream and the reaction was stirred at 150°C for 12 hours. After cooling to room temperature, the DMF was evaporated under reduced pressure. A large amount of water was then added and the mixture was extracted three times with dichloromethane. The organic phases were combined, concentrated, and then filtered through a silica gel column with ethyl acetate:petroleum ether in a ratio of 1:1 to obtain 3.03 g of a yellow solid, intermediate 7b, with a yield of 52%. MALDI-TOF-MS (m / z): 490.5 ([M+1] + ).

[0110] 2. Synthesis of intermediate 7c:

[0111] Intermediate 7b (1.43 g, 2.92 mmol) was added to a dry 100 mL Schlenck tube and evacuated and refilled with nitrogen three times. Dry m-xylene (25 mL) was then added under a nitrogen atmosphere. n-Butyl lithium (1.30 mL, 3.21 mmol) was added at 0°C, and the reaction was stirred at 0°C for 20 minutes. The mixture was then brought to room temperature and stirred for 1 hour. The temperature was then lowered to 0°C, and boron tribromide (0.50 mL, 5.25 mmol) was added. The mixture was stirred at 0°C for 20 minutes, and then brought to room temperature and stirred for 30 minutes. The mixture was then heated to 45°C and stirred for 50 minutes. The temperature was then lowered again to 0°C, and N,N-diisopropylethylamine (1.00 mL, 5.84 mmol) was added. Finally, the mixture was heated to 140°C and stirred for 12 hours. After the reaction was complete, the solution was cooled to room temperature and washed with saturated sodium acetate solution, then extracted several times with water and dichloromethane. The combined organic phases were concentrated by rotary evaporation and dried to obtain approximately 1.05 g of a yellow solid, intermediate 7c, with a yield of 86%. MALDI-TOF-MS (m / z): 419.3 ([M+1] + ).

[0112] 3. Synthesis of intermediate 7d:

[0113] Intermediate 7c (0.84 g, 2 mmol) was placed in a dry Schlenck flask and evacuated and refilled with nitrogen three times. Then, 20 mL of dry tetrahydrofuran was added under a nitrogen stream and stirred at room temperature for ten minutes. Iodomethane (0.50 mL, 8 mmol) was then added and the temperature was raised to 65°C with stirring for three days. After the reaction, the flask was cooled to room temperature and the filter cake was filtered and rinsed with tetrahydrofuran to obtain 0.56 g of a yellow solid, Intermediate 7d, with a yield of 50%. ESI-MS (m / z): 433.4 ([MI] + ).

[0114] 4. Synthesis of boron-containing fused-ring carbene iridium complex M7:

[0115] In a dry Schlenck bottle, intermediate 7d (0.159 g, 0.285 mmol), Ag2O (0.066 g, 0.285 mmol), and [Ir(COD)Cl]2 (0.039 g, 0.057 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Triethylamine (0.04 mL, 0.285 mmol) and chlorobenzene (20 mL) were then added under a nitrogen stream. The reaction was stirred at 120°C for 24 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure. The mixture was then filtered through a silica gel column using dichloromethane:petroleum ether (1:1) to obtain 36 mg of a yellow solid, the boron-containing fused-ring carbene iridium complex M7, with a yield of 21%. MALDI-TOF-MS (m / z): 1486.3 ([M] + ).

[0116] Example 8 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M8

[0117] Synthesis route of boron-containing fused-ring carbene iridium complex M8:

[0118]

[0119] 1. Synthesis of intermediate 8b:

[0120] In a dry Schlenck bottle, intermediate 4a (6.71 g, 11.9 mmol), benzimidazole (2.50 g, 21.2 mmol), CuI (1.0 g, 5.25 mmol), and potassium carbonate (3.0 g, 21.7 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Then, 70 mL of dry DMF was added under a nitrogen stream and the reaction was stirred at 150°C for 12 hours. After cooling to room temperature, the DMF was evaporated under reduced pressure. A large amount of water was then added and the mixture was extracted three times with dichloromethane. The organic phases were combined, concentrated, and then passed through a silica gel column with ethyl acetate:petroleum ether in a ratio of 1:1 to obtain 3.72 g of a yellow solid, intermediate 8b, in a 52% yield. MALDI-TOF-MS (m / z): 602.6 ([M+1] + ).

[0121] 2. Synthesis of intermediate 8c:

[0122] Intermediate 8b (1.75 g, 2.92 mmol) was added to a dry 100 mL Schlenck tube and evacuated and refilled with nitrogen three times. Dry m-xylene (25 mL) was then added under a nitrogen atmosphere. n-Butyl lithium (1.30 mL, 3.21 mmol) was added at 0°C, and the reaction was stirred at 0°C for 20 minutes. The mixture was then brought to room temperature and stirred for 1 hour. The temperature was then lowered to 0°C, and boron tribromide (0.50 mL, 5.25 mmol) was added. The mixture was stirred at 0°C for 20 minutes, and then brought to room temperature and stirred for 30 minutes. The mixture was then heated to 45°C and stirred for 50 minutes. The temperature was then lowered again to 0°C, and N,N-diisopropylethylamine (1.00 mL, 5.84 mmol) was added. Finally, the mixture was heated to 140°C and stirred for 12 hours. After the reaction was completed, the solution was cooled to room temperature and washed with saturated sodium acetate solution, followed by extraction with water and dichloromethane several times. The combined organic phases were concentrated by rotary evaporation and dried to obtain approximately 1.21 g of a yellow solid, intermediate 8c, with a yield of 78%. MALDI-TOF-MS (m / z): 531.7 ([M+1] + ).

[0123] 3. Synthesis of intermediate 8d:

[0124] Intermediate 8c (1.06 g, 2 mmol) was placed in a dry Schlenck flask and evacuated and refilled with nitrogen three times. Then, 20 mL of dry tetrahydrofuran was added under a nitrogen stream and stirred at room temperature for ten minutes. Iodomethane (0.50 mL, 8 mmol) was then added and the temperature was raised to 65°C with stirring for three days. After the reaction, the flask was cooled to room temperature and the filter cake was filtered and rinsed with tetrahydrofuran to obtain 0.74 g of a yellow solid, Intermediate 8d, with a yield of 55%. ESI-MS (m / z): 545.5 ([MI] + ).

[0125] 4. Synthesis of boron-containing fused-ring carbene iridium complex M8:

[0126] In a dry Schlenck bottle, intermediate 8d (0.191 g, 0.285 mmol), Ag2O (0.066 g, 0.285 mmol), and [Ir(COD)Cl]2 (0.039 g, 0.057 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. Then, triethylamine (0.04 mL, 0.285 mmol) and chlorobenzene (20 mL) were added under a nitrogen stream and stirred at 120°C for 24 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure. The mixture was then filtered through a silica gel column with dichloromethane:petroleum ether (1:1) to obtain 58 mg of a yellow solid, the boron-containing fused-ring carbene iridium complex M8, in a yield of 28%. MALDI-TOF-MS (m / z): 1822.9 ([M] + ).

[0127] Example 9 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M9

[0128] Synthesis route of boron-containing fused-ring carbene iridium complex M9:

[0129]

[0130] 1. Synthesis of intermediate 9a:

[0131] In a dry two-necked flask, 1,5-cyclooctadiene iridium chloride dimer (0.44 g, 0.66 mmol) and biphenylene (0.2 g, 1.31 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. 5 mL of dry dichloromethane was then added and stirred at 90°C for 2 hours. The mixture was cooled to room temperature, filtered, and the filter cake was washed with dichloromethane to obtain 0.57 g of a yellow solid, intermediate 9a, with a yield of 85%. MALDI-TOF-MS (m / z): 976.2 ([M] + ).

[0132] 2. Synthesis of intermediate 9b:

[0133] In a dry Schlenck bottle, intermediate 9a (0.10 g, 0.1 mmol), 2,2'-bipyridine (0.03 g, 0.2 mmol), and silver trifluoromethanesulfonate (0.06 g, 0.22 mmol) were placed. The mixture was evacuated and filled with nitrogen for three cycles. 25 mL of dry dichloromethane was then added under a nitrogen stream. The mixture was stirred at room temperature for 2 hours, filtered, and the filtrate was concentrated to 1 mL. A large amount of petroleum ether was then added to precipitate a solid, which was filtered and dried to obtain 0.11 g of a yellow solid, intermediate 9b, with a yield of 75%. ESI-MS (m / z): 608.7 ([M-OTf] + ).

[0134] 3. Synthesis of boron-containing fused-ring carbene iridium complex M9:

[0135] In a dry two-necked flask were placed intermediate 9b (0.076 g, 0.1 mmol), 1d (0.057 g, 0.12 mmol), and Na2CO3 (0.03 g, 0.24 mmol). The mixture was evacuated and filled with nitrogen three times. Then, 20 mL of ethylene glycol monoethyl ether was added under a nitrogen stream. The mixture was stirred and refluxed at 130°C for 24 hours. The mixture was cooled to room temperature, and the organic phase was concentrated. Water was then added, and the mixture was extracted with dichloromethane, concentrated, and filtered through a silica gel column with dichloromethane:petroleum ether (5:1) to obtain 38 mg of a red solid, the boron-containing fused-ring carbene iridium complex M9, with a yield of 45%. MALDI-TOF-MS (m / z): 849.5 ([M] + ). The X-ray single crystal structure of M9 is shown in Figure 2 .

[0136] Example 10 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M13

[0137] Synthesis route of boron-containing fused-ring carbene iridium complex M13:

[0138]

[0139] 1. Synthesis of boron-containing fused-ring carbene iridium complex M13:

[0140] In a dry two-necked flask were placed intermediate 9b (0.076 g, 0.1 mmol), 5d (0.063 g, 0.12 mmol), and Na2CO3 (0.03 g, 0.24 mmol). The mixture was evacuated and filled with nitrogen three times. Then, 20 mL of ethylene glycol monoethyl ether was added under a nitrogen stream. The mixture was stirred and refluxed at 130°C for 24 hours. The mixture was cooled to room temperature, and the organic phase was concentrated. Water was then added, and the mixture was extracted with dichloromethane, concentrated, and filtered through a silica gel column with dichloromethane:petroleum ether (5:1) to obtain 43 mg of a red solid, the boron-containing fused-ring carbene iridium complex M13, in a yield of 48%. MALDI-TOF-MS (m / z): 900.3 ([M+1] + ). The X-ray single crystal structure of M13 is shown in Figure 3 .

[0141] Example 11 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M17

[0142] Synthesis route of boron-containing fused-ring carbene iridium complex M17:

[0143]

[0144] 1. Synthesis of intermediate 10b:

[0145] In a dry Schlenck bottle, intermediate 1a (0.10 g, 0.1 mmol), 1,10-phenanthroline (0.04 g, 0.2 mmol), and silver trifluoromethanesulfonate (0.06 g, 0.22 mmol) were placed. The mixture was evacuated and filled with nitrogen three times. 25 mL of dry dichloromethane was then added under a nitrogen stream. The mixture was stirred at room temperature for 2 hours, filtered, and the filtrate was concentrated to 1 mL. A large amount of petroleum ether was then added to precipitate a solid, which was filtered and dried to obtain 0.12 g of a yellow solid, intermediate 10b, in a 75% yield. ESI-MS (m / z): 632.8 ([M-OTf] + ).

[0146] 2. Synthesis of boron-containing fused-ring carbene iridium complex M17:

[0147] In a dry two-necked flask were placed intermediate 10b (0.078 g, 0.1 mmol), 1d (0.057 g, 0.12 mmol), and Na2CO3 (0.03 g, 0.24 mmol). The mixture was evacuated and filled with nitrogen three times. Then, 20 mL of ethylene glycol monoethyl ether was added under a nitrogen stream. The mixture was stirred and refluxed at 130°C for 24 hours. The mixture was cooled to room temperature, and the organic phase was concentrated. Water was added, the mixture was extracted with dichloromethane, concentrated, and filtered through a silica gel column with dichloromethane:petroleum ether (5:1) to obtain 46 mg of a red solid, the boron-containing fused-ring carbene iridium complex M17, in a 53% yield. MALDI-TOF-MS (m / z): 873.8 ([M] + ). The X-ray single crystal structure of M17 is shown in Figure 4 .

[0148] Example 12 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M18

[0149] Synthesis route of boron-containing fused-ring carbene iridium complex M18:

[0150]

[0151] 1. Synthesis of boron-containing fused-ring carbene iridium complex M18:

[0152] In a dry two-necked flask were placed intermediate 10b (0.078 g, 0.1 mmol), 2d (0.071 g, 0.12 mmol), and Na2CO3 (0.03 g, 0.24 mmol). The mixture was evacuated and filled with nitrogen three times. Then, 20 mL of ethylene glycol monoethyl ether was added under a nitrogen stream. The mixture was stirred and refluxed at 130°C for 24 hours. The mixture was cooled to room temperature, and the organic phase was concentrated. Water was added, the mixture was extracted with dichloromethane, concentrated, and filtered through a silica gel column with dichloromethane:petroleum ether (5:1) to obtain 49 mg of a red solid, the boron-containing fused-ring carbene iridium complex M18, with a yield of 50%. MALDI-TOF-MS (m / z): 987.1 ([M+1] + ).

[0153] Example 13 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M20

[0154] Synthesis route of boron-containing fused-ring carbene iridium complex M20:

[0155]

[0156] 1. Synthesis of boron-containing fused-ring carbene iridium complex M20:

[0157] In a dry two-necked flask were placed intermediate 10b (0.078 g, 0.1 mmol), 4d (0.075 g, 0.12 mmol), and Na2CO3 (0.03 g, 0.24 mmol). The mixture was evacuated and filled with nitrogen three times. Then, 20 mL of ethylene glycol monoethyl ether was added under a nitrogen stream. The mixture was stirred and refluxed at 130°C for 24 hours. The mixture was cooled to room temperature, and the organic phase was concentrated. Water was added, the mixture was extracted with dichloromethane, concentrated, and filtered through a silica gel column with dichloromethane:petroleum ether (5:1) to obtain 44 mg of a red solid, the boron-containing fused-ring carbene iridium complex M20, with a yield of 43%. MALDI-TOF-MS (m / z): 1018.3 ([M] + ).

[0158] Example 14 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M21

[0159] Synthesis route of boron-containing fused-ring carbene iridium complex M21:

[0160]

[0161] 1. Synthesis of boron-containing fused-ring carbene iridium complex M21:

[0162] In a dry two-necked flask were placed intermediate 10b (0.078 g, 0.1 mmol), 5d (0.063 g, 0.12 mmol), and Na2CO3 (0.03 g, 0.24 mmol). The mixture was evacuated and filled with nitrogen three times. Then, 20 mL of ethylene glycol monoethyl ether was added under a nitrogen stream. The mixture was stirred and refluxed at 130°C for 24 hours. The mixture was cooled to room temperature, and the organic phase was concentrated. Water was added, the mixture was extracted with dichloromethane, concentrated, and filtered through a silica gel column with dichloromethane:petroleum ether (5:1) to obtain 48 mg of a red solid, the boron-containing fused-ring carbene iridium complex M21, with a yield of 52%. MALDI-TOF-MS (m / z): 924.9 ([M] + ). The X-ray single crystal structure of M21 is shown in Figure 5 .

[0163] Example 15 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M22

[0164] Synthesis route of boron-containing fused-ring carbene iridium complex M22:

[0165]

[0166] 1. Synthesis of boron-containing fused-ring carbene iridium complex M22:

[0167] In a dry two-necked flask were placed intermediate 10b (0.078 g, 0.1 mmol), 6d (0.076 g, 0.12 mmol), and Na2CO3 (0.03 g, 0.24 mmol). The mixture was evacuated and filled with nitrogen three times. Then, 20 mL of ethylene glycol monoethyl ether was added under a nitrogen stream. The mixture was stirred and refluxed at 130°C for 24 hours. The mixture was cooled to room temperature, and the organic phase was concentrated. Water was added, the mixture was extracted with dichloromethane, concentrated, and filtered through a silica gel column with dichloromethane:petroleum ether (5:1) to obtain 55 mg of a red solid, the boron-containing fused-ring carbene iridium complex M22, in a yield of 53%. MALDI-TOF-MS (m / z): 1036.1 ([M] + ).

[0168] Example 16 Synthesis of Boron-Containing Condensed Ring Carbene Iridium Complex M24

[0169] Synthesis route of boron-containing fused-ring carbene iridium complex M24:

[0170]

[0171] 1. Synthesis of boron-containing fused-ring carbene iridium complex M24:

[0172] In a dry two-necked flask were placed intermediate 10b (0.078 g, 0.1 mmol), 8d (0.081 g, 0.12 mmol), and Na2CO3 (0.03 g, 0.24 mmol). The mixture was evacuated and filled with nitrogen three times. Then, 20 mL of ethylene glycol monoethyl ether was added under a nitrogen stream. The mixture was stirred and refluxed at 130°C for 24 hours. The mixture was cooled to room temperature, and the organic phase was concentrated. Water was then added, and the mixture was extracted with dichloromethane, concentrated, and filtered through a silica gel column with dichloromethane:petroleum ether (5:1) to obtain 52 mg of a red solid, the boron-containing fused-ring carbene iridium complex M24, with a yield of 49%. MALDI-TOF-MS (m / z): 1069.3 ([M+1] + ).

[0173] Example 17 Synthesis of Boron-Containing Condensed Ring Carbene Platinum Complex M28

[0174] Synthesis route of boron-containing fused-ring carbene platinum complex M28:

[0175]

[0176] 1. Synthesis of boron-containing fused-ring carbene platinum complex M35:

[0177] Intermediate 2d (0.472 g, 0.8 mmol) and Ag2O (0.092 g, 0.4 mmol) were placed in a dry Schlenck bottle, and the mixture was evacuated and filled with nitrogen for three cycles. Then, 1,4-dioxane (20 mL) was added under a nitrogen flow, and the mixture was stirred at room temperature for 16 hours. Then, butanone (10 mL) and 1,5-cyclooctadiene dichloroplatinum (0.299 g, 0.8 mmol) were added under nitrogen, and the mixture was heated and stirred at reflux for 16 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure, and DMF (20 mL) was added to dissolve it. 2,2,6,6-tetramethyl-3,5-heptanedione (0.67 mL, 3.2 mmol) and potassium tert-butoxide (0.359 g, 3.2 mmol) were then added. The mixture was stirred at room temperature under nitrogen for 16 hours, and then stirred at 100°C for 6 hours. The mixture was cooled to room temperature, the solvent was evaporated under reduced pressure, and then filtered through a silica gel column with dichloromethane to obtain 0.268 g of an orange solid, which was the boron-containing fused-ring carbene platinum complex M28, with a yield of 40%. MALDI-TOF-MS (m / z): 840.8 ([M+1] + ).

[0178] Example 18 Synthesis of Boron-Containing Condensed Ring Carbene Platinum Complex M36

[0179] Synthesis route of boron-containing fused-ring carbene platinum complex M36:

[0180]

[0181] 1. Synthesis of boron-containing fused-ring carbene platinum complex M36:

[0182] In a dry Schlenck bottle, intermediate 6d (0.512 g, 0.8 mmol) and Ag2O (0.092 g, 0.4 mmol) were placed, and the mixture was evacuated and filled with nitrogen for three cycles. Then, 1,4-dioxane (20 mL) was added under a nitrogen flow, and the mixture was stirred at room temperature for 16 hours. Then, butanone (10 mL) and 1,5-cyclooctadiene dichloroplatinum (0.299 g, 0.8 mmol) were added under nitrogen, and the mixture was heated and stirred at reflux for 16 hours. After cooling to room temperature, the solvent was evaporated under reduced pressure, and DMF (20 mL) was added to dissolve the mixture. 2,2,6,6-tetramethyl-3,5-heptanedione (0.67 mL, 3.2 mmol) and potassium tert-butoxide (0.359 g, 3.2 mmol) were then added. The mixture was stirred at room temperature under nitrogen for 16 hours, and then stirred at 100°C for 6 hours. The mixture was cooled to room temperature, the solvent was evaporated under reduced pressure, and the mixture was filtered through a silica gel column with dichloromethane to obtain 0.249 g of an orange solid, which was the boron-containing fused-ring carbene platinum complex M36, with a yield of 35%. MALDI-TOF-MS (m / z): 889.8 ([M] + ).

[0183] Example 19 Preparation and Characterization of OLED Devices

[0184] The preparation steps of OLED devices with ITO / PEDOT:PSS (50nm) / M1-M36 (1wt%):mCP and m-MTDATA (40nm) / DPEPO (10nm) / TmPyPB (50nm) / Liq (1nm) / Al (100nm) are as follows:

[0185] (i) ultrasonically treating the ITO surface with an aqueous solution of 5% Decon 90 cleaning solution for 30 minutes, followed by ultrasonic cleaning with deionized water several times, ultrasonic cleaning with isopropyl alcohol, and drying with nitrogen; and treating the surface with oxygen plasma for 5 minutes to clean the ITO surface and improve the work function of the ITO electrode;

[0186] (ii) A 50 nm film was obtained by spin-coating a PEDOT:PSS solution onto an oxygen plasma-treated ITO glass substrate. The film was then annealed in air at 150°C for 20 minutes. PEDOT:PSS is an aqueous polymer solution composed of two substances: PEDOT (3,4-ethylenedioxythiophene) and PSS (polystyrene sulfonate).

[0187] (iii) mCP, m-MTDATA, and complexes (M1-M36) were dissolved in toluene at a specific mass ratio. Complexes M1-M36 were doped as guest materials in a mixed host material, mCP and m-MTDATA, at a weight ratio of 1 wt%. This solution was spin-coated in a nitrogen glove box to obtain a 40 nm thin film, which was then annealed at 120°C for 10 minutes. mCP stands for 1,3-dicarbazol-9-ylbenzene, and m-MTDATA stands for 4,4',4"-tris(N-3-methylphenyl-N-phenylamino)triphenylamine.

[0188] (iv) The spin-coated device was placed in a vacuum evaporation chamber, and 10nm DPEPO, 50nm TmPyPB, 1nm Liq and 100nm aluminum were evaporated in sequence to produce an OLED light-emitting device. DPEPO is the abbreviation of di[2-((oxy)diphenylphosphino)phenyl]ether, TmPyPB is the abbreviation of 1,3,5-tris(3-pyridyl-3-phenyl)benzene, and Liq is the abbreviation of 8-hydroxyquinoline lithium. The current-voltage-luminance (JVL) characteristics of the OLED device were characterized using a characterization device, and important parameters such as efficiency and external quantum efficiency were recorded. After testing, the maximum external quantum efficiency (EQE) of the OLED was 23%. The details are as follows:

[0189] Complex M1 M2 M3 M4 M5 M6 M7 M8 M9 EQE 19.5％ 20.5％ 18.7％ 19.3％ 22.5％ 23％ 19.4％ 20.5％ 16.2％ Complex M13 M17 M18 M20 M21 M22 M24 M35 M36 EQE 16.5％ 17.2％ 17.5％ 16.3％ 18.2％ 18.7％ 13.2％ 19.5％ 20.3％

[0190] Further optimization, such as optimization of device structure and combination optimization of hole transport materials (HTM), electron transport materials (ETM) and host materials, will further improve device performance, especially efficiency, driving voltage and life.

Claims

1. A boron-containing fused-ring carbene iridium and platinum complex, characterized in that: The boron-containing fused-ring carbene iridium and platinum complex is selected from the following compounds M1-M40:

2. The method for preparing the boron-containing fused-ring carbene iridium and platinum complex according to claim 1, characterized in that: The following steps are involved: 1) First, 2,5-dibromo-1,3-difluorobenzene is used as a raw material, and phenol and its derivatives or thiophenol and its derivatives are subjected to a fluorine substitution reaction in an alkaline high temperature environment to obtain a first-step precursor, and then the precursor is subjected to an Ullmann reaction with imidazole or benzimidazole in the presence of a base and cuprous iodide to obtain the corresponding second-step precursor; 2) The second precursor prepared in step 1) is further subjected to removal of bromine atoms using n-butyl lithium n-BuLi in a dry m-xylene solution under anhydrous, oxygen-free, and low-temperature conditions, followed by addition of boron tribromide and stirring for reaction. Finally, in an alkaline environment of N,N-diisopropylethylamine, the reaction temperature and time are controlled to obtain a boron-containing fused ring intermediate compound, which is then methylated using iodomethane to form a boron-containing fused ring imidazole salt or benzimidazole salt ligand; 3) Finally, the boron-containing fused ring imidazole salt or benzimidazole salt ligand prepared in step 2) is used to carry out coordination reaction with metal iridium and platinum respectively to obtain boron-containing fused ring carbene iridium and platinum complexes.

3. The method for preparing a boron-containing fused-ring carbene iridium and platinum complex according to claim 2, wherein: In step 1), the reaction temperature is 150-170° C., and the reaction time is 12-24 hours.

4. The method for preparing a boron-containing fused-ring carbene iridium and platinum complex according to claim 3, wherein: In step 2), the low temperature condition is 0° C. to 45° C., and the reaction time is 20 to 120 minutes.

5. The method for preparing a boron-containing fused-ring carbene iridium and platinum complex according to claim 3, characterized in that: In step 3), the reaction temperature is 100-130° C., and the reaction time is 6-24 h.

6. Use of the boron-containing fused-ring carbene iridium and platinum complex according to claim 1 in the preparation of organic electronic devices.

7. The use according to claim 6, characterized in that The organic electronic device includes one or more of an organic light emitting diode, an organic photovoltaic cell, an organic light emitting cell, an organic field effect transistor, an organic laser, an organic spintronic device, an organic sensor or an organic plasmon emission diode.

8. The use according to claim 6, characterized in that The mass concentration of the boron-containing fused-ring carbene iridium and platinum complex in the matrix is ​​1-15 wt %.

9. An organic electronic device, characterized in that: The organic electronic device comprises the boron-containing fused-ring carbene iridium and platinum complex according to claim 1.

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