A class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups, their preparation methods and applications

Abstract

A class of deep-red to near-infrared iridium(III) complexes containing fluoranthene groups, their preparation methods, and applications are disclosed. The general chemical formula of the complexes is obtained by introducing electron-rich fluoranthene groups with strong rigidity and large π-conjugated planes, and modifying them with different functional groups to enhance the hole transport performance of the molecules. At the same time, fluoranthene is modified with electron-deficient functional groups to synthesize a series of organic ligands. The designed ligands have both large conjugation and strong charge transfer characteristics. The emission spectrum of the complexes can be redshifted in a simple step to obtain a series of deep-red to near-infrared iridium(III) complexes, achieving long-wavelength emission from deep red to near-infrared at 672nm, 690nm, 692nm, and 738nm. These can be used as organic light-emitting materials in the light-emitting layer of OLED devices, providing a new molecular design idea for the development of organic near-infrared light-emitting materials. In addition, the preparation method is simple, the raw materials are readily available, the cost is low, and it can be mass-produced, which has great practical value.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials technology, specifically to a class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups, their preparation methods, and their applications. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have become the most promising next-generation flat panel display technology due to their advantages such as self-illumination, flexibility, ultra-thinness, and high contrast. In recent years, OLED products have gradually appeared in the industrial market for various flat panel displays, including home TVs and smartphones, and have achieved large-scale mass production. The demand for the entire OLED market supply chain is expanding, making upgrades and replacements increasingly urgent. In OLED devices, the organic light-emitting material, as the light-emitting layer, is extremely crucial. Its excellent photoluminescence efficiency, color purity, carrier transport capacity, thermal stability, and electrochemical stability all play an indispensable role in the performance of OLED devices.

[0003] Initially, organic light-emitting materials were mainly fluorescent materials, but their luminous efficiency was limited to 25%, restricting device performance and hindering large-scale commercial applications. However, the introduction of heavy atoms from transition metals enhanced spin-orbit coupling, enabling phosphorescence emission and potentially achieving 100% internal quantum efficiency. This significantly improved OLED device efficiency, leading to the widespread development of phosphorescent materials. Iridium (III) complexes, with their six-coordinate octahedral structure, possess advantages such as high exciton utilization, good stability, short phosphorescence lifetime, and easily tunable color, making them a highly promising class of phosphorescent materials. Significant progress has been made with transition metal iridium (III) complexes in the visible light region. For example, patent publication number CN 114149334 B reported the application of fluoranthene derivatives in the capping layer of OLED devices with beneficial effects. However, research on transition metal iridium (III) complexes in the deep red to near-infrared (DR-NIR) region, and their potential use as materials for other functional layers in OLED devices, remains to be studied. Summary of the Invention

[0004] To address the aforementioned shortcomings, the present invention aims to provide a class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups, their preparation, and applications. Modification with rigid fluoranthene groups enhances intramolecular charge transfer, expands π-conjugation, and strengthens charge transfer in the luminescent molecules, achieving a redshift in the emission spectrum. Simultaneously, to improve color purity, the rigidity of the complex molecule needs to be designed to increase its rigidity. Fluoranthene groups are highly rigid, exhibiting a large π-conjugated plane, possessing excellent hole injection capabilities, and are readily available and simple to prepare, making them suitable for controlling the luminescence color and properties of complexes.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups have the following general structural formula:

[0007]

[0008] In the above formula, Ar is selected from any of the following groups:

[0009]

[0010] The complex comprises the following four structures:

[0011]

[0012] A method for preparing a class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups involves dissolving IrCl3 and an organic ligand in a mixed solvent of ethylene glycol ethyl ether and water under an inert gas atmosphere until completely dissolved, heating to 100–110 °C and stirring for 12–18 h. After the reaction is complete, the reaction mixture is poured into water and extracted with dichloromethane. The resulting organic phase is dried with anhydrous sodium sulfate and then concentrated under vacuum to obtain the intermediate dimer. The concentrated intermediate dimer is completely dissolved with t-BuOK and acetylacetone in dichloromethane and stirred at 25–30 °C for 10–16 h under an inert gas atmosphere. After the reaction is complete, the reaction mixture is poured into water and extracted with dichloromethane. The resulting organic phase is dried with anhydrous sodium sulfate and then concentrated under vacuum to obtain the crude product. The crude product is then separated by silica gel column chromatography to obtain the target deep red to near-infrared iridium(III) complex.

[0013] The inert gases are either nitrogen or argon.

[0014] The molar ratio of IrCl3 to the organic ligand is 1:(2.1-2.2), and the volume ratio of the mixed solvent of ethylene glycol ethyl ether and water is 3:1.

[0015] The molar ratio of the intermediate dimer to t-BuOK and acetylacetone is 1:(3-5):(6-10).

[0016] The organic ligand is prepared by the following method:

[0017] Step 1: Synthesize the boron ester reaction intermediate containing fluoranthene groups, specifically as follows:

[0018] Under an inert gas atmosphere, 3-bromofluoranthene, pinacol diboronate, 1,1-bis(diphenylphosphine)ferrocene palladium(II) dichloride and potassium acetate were completely dissolved in dioxane. The reaction mixture was reacted at 100–110 °C for 12–16 h. After the reaction was completed, the mixture was cooled to room temperature and poured into water. It was extracted with dichloromethane, dried over anhydrous sodium sulfate, and concentrated under vacuum to obtain the crude product. The crude product was then separated by silica gel column chromatography to obtain the borate ester reaction intermediate.

[0019] Step 2: Synthesize organic ligands containing fluoranthene groups. The specific steps are as follows:

[0020] Under an inert gas atmosphere, the borate ester reaction intermediate obtained in step one, the haloaromatic fused ring and tetra-triphenylphosphine palladium were completely dissolved in a mixed solution of toluene and potassium carbonate aqueous solution. The reaction mixture was reacted at 100-110°C for 16-18 h under inert gas protection. After the reaction was completed, the mixture was cooled to room temperature and poured into water. It was extracted with dichloromethane, and the organic phase was dried with anhydrous sodium sulfate. The crude product obtained by vacuum concentration was separated by silica gel column chromatography to obtain the synthesized organic ligand containing fluoranthene group.

[0021] In steps one and two, the inert gas is either nitrogen or argon.

[0022] In step one, the molar ratio of 3-bromofluoranthene, pinacol diboronate, 1,1-bis(diphenylphosphine)ferrocene palladium(II) dichloride and potassium acetate is 1:(1.2-1.5):(0.03-0.05):3.

[0023] In step two, the molar ratio of the borate ester reaction intermediate, the halogenated aromatic fused ring, and tetra-triphenylphosphine palladium is 1:(1.2-1.5):(0.03-0.05).

[0024] The volume ratio of the mixed solution of toluene and potassium carbonate aqueous solution is (1-3):1.

[0025] In step two, the halogenated aromatic fused ring is 1-chloroisoquinoline, 2-chloroquinoline, 2-bromopyridine, or 2-bromobenzothiazole, and the resulting ligands are respectively L-1, L-2, L-3, or L-4.

[0026] The application of a class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups as organic light-emitting materials in the light-emitting layer of OLED devices.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. Step one of this invention enhances the hole transport performance of molecules by introducing an electron-rich fluoranthene group with strong rigidity and a large π-conjugated plane. At the same time, the fluoranthene is modified with an electron-deficient functional group to synthesize a series of organic ligands. The designed ligands have both large conjugation and strong charge transfer characteristics. A red shift of the emission spectrum of the complex can be achieved in a simple step, and a series of deep red to near-infrared iridium(III) complexes can be obtained to achieve long-wavelength emission from deep red to near-infrared with emission colors from 672nm, 690nm, 692nm and 738nm.

[0029] 2. The deep red to near-infrared iridium(III) complexes containing fluoranthene groups designed and synthesized in this invention have a beneficial effect of achieving a pure near-infrared content (NIR%) of up to 94%. This provides a new design idea for the research of pure near-infrared iridium(III) complexes and has great development prospects in night vision display, sensors, biomedicine and other fields.

[0030] In summary, this invention introduces a rigid fluoranthene group into the ligand and modifies it with different functional groups to achieve regulation, thereby obtaining novel deep red to near-infrared iridium(III) complex phosphorescent materials, providing a new molecular design approach for the development of organic near-infrared luminescent materials. In addition, its preparation method is simple, the raw materials are readily available, the cost is low, and it can be mass-produced, thus having great practical value. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the synthetic route for preparing the target iridium(III) complex according to the present invention.

[0032] Figure 2 This is the high-resolution mass spectrum of the target iridium(III) complex 1 provided by the present invention.

[0033] Figure 3 The NMR spectrum of the target iridium(III) complex 2 provided by this invention is shown.

[0034] Figure 4 This is the NMR spectrum of the target iridium(III) complex 3 provided by the present invention.

[0035] Figure 5 The NMR spectrum of the target iridium(III) complex 4 provided by this invention is shown.

[0036] Figure 6 This is the steady-state spectrum of the target iridium(III) complex provided by the present invention. Detailed Implementation

[0037] To illustrate in detail the deep red to near-infrared iridium(III) complexes containing fluoranthene groups involved in this invention, the specific synthesis steps of this invention are described in detail below with reference to examples.

[0038] The embodiments listed below are merely preferred embodiments of the present invention and do not limit the invention. Those skilled in the art can make modifications and variations to the present invention as needed. All modifications, substitutions, etc., made based on the principles and spirit of the present invention should be included within the scope of protection of the present invention.

[0039] Example 1

[0040] The target molecular structure in this embodiment is:

[0041]

[0042] See attached document Figure 1 The target molecule is a reaction intermediate for synthesizing a borate ester containing a fluoranthracene group. The synthetic steps are as follows:

[0043] Under a nitrogen atmosphere, 3-bromofluoranthene (1 eq), pinacol diborate (1.5 eq), 1,1-bis(diphenylphosphine)ferrocene palladium(II) dichloride (0.05 eq), and potassium acetate (3 eq) were dissolved in 30 mL of dioxane. The reaction mixture was reacted at 110 °C for 12 h under nitrogen protection. After the reaction was complete, the mixture was cooled to room temperature and poured into 80 mL of water. The mixture was extracted three times with 30 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain the target product as a white solid, with a yield of 71%. NMR characterization data: 1 H NMR (400MHz, Chloroform-d) δ8.60(d,J=8.0Hz,1H),8.23(d,J=8.0Hz,1H),7.96–7.87(m,4H),7.65(m,1H),7.42–7.34(m,2H),1.45(s,12H).

[0044] Example 2

[0045] The structure of the target deep-infrared to near-infrared iridium(III) complex 1 in this embodiment is as follows:

[0046]

[0047] See attached document Figure 1 The synthetic steps of the target molecule are as follows:

[0048] 1) Under a nitrogen atmosphere, FT-Bpin (1 eq), 1-chloroisoquinoline (1.2 eq), and tetraphenylphosphine palladium (0.05 eq) obtained in Example 1 were dissolved in 30 mL of a mixed solution of toluene and potassium carbonate aqueous solution (mixing volume ratio 1:1). The reaction mixture was reacted at 110 °C for 16 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, poured into 100 mL of water, and extracted three times with 40 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain ligand L-1.

[0049] 2) Under a nitrogen atmosphere, IrCl3 (1 eq) and ligand L-1 (2.2 eq) were dissolved in a mixed solvent of ethylene glycol diethyl ether and water (volume ratio 3:1), and the mixture was heated to 110 °C and stirred for 18 h. After the reaction, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the intermediate. The concentrated dark solid was dissolved in dichloromethane with t-BuOK (5 eq) and acetylacetone (10 eq), and stirred at 30 °C for 16 h under a nitrogen atmosphere. After the reaction, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain target molecule 1, with a yield of 25%. HRMS characterization data: theoretical value 987.1959, experimental value 987.1942 [M+K] + .

[0050] Example 3

[0051] The structure of the target deep-infrared to near-infrared iridium(III) complex 2 in this embodiment is as follows:

[0052]

[0053] See attached document Figure 1 The synthetic steps of the target molecule are as follows:

[0054] 1) Under a nitrogen atmosphere, FT-Bpin (1 eq), 2-chloroquinoline (1.2 eq), and tetraphenylphosphine palladium (0.05 eq) obtained in Example 1 were dissolved in 30 mL of a mixed solution of toluene and potassium carbonate aqueous solution (mixing volume ratio 1:1). The reaction mixture was reacted at 110 °C for 16 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, poured into 100 mL of water, and extracted three times with 40 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain ligand L-2.

[0055] 2) Under a nitrogen atmosphere, IrCl3 (1 eq) and ligand L-1 (2.2 eq) were dissolved in a mixed solvent of ethylene glycol ethyl ether and water (volume ratio 3:1), and the mixture was heated to 110 °C and stirred for 18 h. After the reaction, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain an intermediate. The concentrated dark solid was dissolved in dichloromethane with t-BuOK (5 eq) and acetylacetone (10 eq), and stirred at 30 °C for 16 h under a nitrogen atmosphere. After the reaction, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain a crude product. The crude product was separated by silica gel column chromatography to obtain target molecule 2 in 23% yield. NMR characterization data: 1 H NMR (400MHz, Chloroform-d) δ8.88(d,J=8.0Hz,2H),8.69(d,J=8.0Hz,2H),8.33(d,J=8.0Hz,2H),8.21(d,J=8.0Hz,2H),7.85(d, J=8.0Hz,2H),7.79(d,J=8.0Hz,2H),7.71(m,6H),7.45(m,3H),7.32(s,1H),7.16(m,3H),7.01(m,3H),4.51(s,1H),1.44(s,6H).

[0056] Example 4

[0057] The structure of the target deep-infrared to near-infrared iridium(III) complex 3 in this embodiment is as follows:

[0058]

[0059] See attached document Figure 1 The synthetic steps of the target molecule are as follows:

[0060] 1) Under a nitrogen atmosphere, FT-Bpin (1 eq), 2-bromopyridine (1.2 eq), and tetraphenylphosphine palladium (0.05 eq) obtained in Example 1 were dissolved in 30 mL of a mixed solution of toluene and potassium carbonate aqueous solution (mixing volume ratio 1:1). The reaction mixture was reacted at 110 °C for 16 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, poured into 100 mL of water, and extracted three times with 40 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain ligand L-3.

[0061] 2) Under a nitrogen atmosphere, IrCl3 (1 eq) and ligand L-1 (2.2 eq) were dissolved in a mixed solvent of ethylene glycol ethyl ether and water (volume ratio 3:1), and the mixture was heated to 110 °C and stirred for 18 h. After the reaction, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain an intermediate. The concentrated dark solid was dissolved in dichloromethane with t-BuOK (5 eq) and acetylacetone (10 eq), and stirred at 30 °C under a nitrogen atmosphere for 16 h. After the reaction, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain a crude product. The crude product was separated by silica gel column chromatography to obtain target molecule 3 in 27% yield. NMR characterization data: 1 H NMR(400MHz,Chloroform-d)δ8.70(d,J=8.0Hz,2H),8.66(d,J=4.0Hz,2H),8.47(d,J=8.0Hz,2H),7.95(m,2H ),7.69(m,5H),7.60–7.55(m,2H),7.36(d,J=8.0Hz,2H),7.15(m,5H),6.90(s,2H),5.27(s,1H),1.80(s,6H).

[0062] Example 5

[0063] The structure of the target deep-infrared to near-infrared iridium(III) complex 4 in this embodiment is as follows:

[0064]

[0065] See attached document Figure 1 The synthetic steps of the target molecule are as follows:

[0066] 1) Under a nitrogen atmosphere, FT-Bpin (1 eq), 2-bromobenzothiazole (1.2 eq), and tetraphenylphosphine palladium (0.05 eq) obtained in Example 1 were dissolved in 30 mL of a mixed solution of toluene and potassium carbonate aqueous solution (mixing volume ratio 1:1). The reaction mixture was reacted at 110 °C for 16 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, poured into 100 mL of water, and extracted three times with 40 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain ligand L-4.

[0067] 2) Under a nitrogen atmosphere, IrCl3 (1 eq) and ligand L-1 (2.2 eq) were dissolved in a mixed solvent of ethylene glycol ethyl ether and water (volume ratio 3:1), and the mixture was heated to 110 °C and stirred for 18 h. After the reaction, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain an intermediate. The concentrated dark solid was dissolved in dichloromethane with t-BuOK (5 eq) and acetylacetone (10 eq), and stirred at 30 °C for 16 h under a nitrogen atmosphere. After the reaction, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain a crude product. The crude product was separated by silica gel column chromatography to obtain target molecule 4, with a yield of 20%. NMR characterization data: 1 H NMR(600MHz,Chloroform-d)δ8.46(d,J=6.0Hz,2H),8.11(d,J=12.0Hz,2H),8.05(d,J=6.0Hz,2H),7.73(d,J=6.0Hz,2H) ,7.68(m,4H),7.50(m,2H),7.42(m,2H),7.21(d,J=6.0Hz,2H),7.16(m,2H),7.08–7.05(m,4H),5.11(s,1H),1.76(s,6H).

[0068] The deep red to near-infrared iridium(III) complexes 1-4 prepared in Examples 2 to 5 of this invention enhance the hole transport performance of molecules by introducing electron-rich fluoranthene groups with strong rigidity and large π-conjugated planes. At the same time, fluoranthene is modified with electron-deficient functional groups to synthesize a series of organic ligands. The designed ligands have both large conjugation and strong charge transfer characteristics, achieving a redshift in the emission spectrum of the complexes and realizing long-wavelength emission of deep red to near-infrared colors from 672nm, 690nm, 692nm, and 738nm. They can be used as organic light-emitting materials in the light-emitting layer of OLED devices.

[0069] Example 6

[0070] This example illustrates the synthesis steps of the boron ester reaction intermediate FT-Bpin containing fluoranthene groups under different reaction conditions:

[0071] Under a nitrogen atmosphere, 3-bromofluoranthene (1 eq), pinacol diborate (1.2 eq), 1,1-bis(diphenylphosphine)ferrocene palladium(II) dichloride (0.03 eq), and potassium acetate (3 eq) were dissolved in 30 mL of dioxane. The reaction mixture was reacted at 100 °C for 16 h under nitrogen protection. After the reaction was complete, the mixture was cooled to room temperature and poured into 80 mL of water. The mixture was extracted three times with 30 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain the target product as a white solid in 73% yield.

[0072] Example 7

[0073] This embodiment describes the synthesis steps of the target deep red to near-infrared iridium(III) complex 1 under different reaction conditions:

[0074] 1) Under a nitrogen atmosphere, FT-Bpin (1 eq), 1-chloroisoquinoline (1.5 eq), and tetraphenylphosphine palladium (0.05 eq) obtained in Example 1 were dissolved in 30 mL of a mixed solution of toluene and potassium carbonate aqueous solution (mixing volume ratio 3:1). The reaction mixture was reacted at 100 °C for 18 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, poured into 100 mL of water, and extracted three times with 40 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain ligand L-1.

[0075] 2) Under a nitrogen atmosphere, IrCl3 (1 eq) and ligand L-1 (2.2 eq) were dissolved in a mixed solvent of ethylene glycol ethyl ether and water (volume ratio 3:1), and the mixture was heated to 110 °C and stirred for 18 h. After the reaction was complete, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain an intermediate. The concentrated dark solid was dissolved in dichloromethane with t-BuOK (5 eq) and acetylacetone (10 eq), and stirred at 30 °C for 16 h under a nitrogen atmosphere. After the reaction was complete, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain a crude product. The crude product was separated by silica gel column chromatography to obtain target molecule 1 in 24% yield.

[0076] Example 8

[0077] This embodiment describes the synthesis steps of the target deep red to near-infrared iridium(III) complex 2 under different reaction conditions:

[0078] 1) Under a nitrogen atmosphere, FT-Bpin (1 eq), 2-chloroquinoline (1.3 eq), and tetraphenylphosphine palladium (0.04 eq) obtained in Example 1 were dissolved in 30 mL of a mixed solution of toluene and potassium carbonate aqueous solution (mixing volume ratio 2:1). The reaction mixture was reacted at 110 °C for 17 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, poured into 100 mL of water, and extracted three times with 40 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain ligand L-2.

[0079] 2) Under a nitrogen atmosphere, IrCl3 (1 eq) and ligand L-1 (2.1 eq) were dissolved in a mixed solvent of ethylene glycol ethyl ether and water (volume ratio 3:1), and the mixture was heated to 110 °C and stirred for 16 h. After the reaction was complete, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain an intermediate. The concentrated dark solid was dissolved in dichloromethane with t-BuOK (3 eq) and acetylacetone (6 eq), and stirred at 25 °C for 17 h under a nitrogen atmosphere. After the reaction was complete, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain a crude product. The crude product was separated by silica gel column chromatography to obtain target molecule 2 in 22% yield.

[0080] Example 9

[0081] This embodiment describes the synthesis steps of the target deep red to near-infrared iridium(III) complex 3 under different reaction conditions:

[0082] 1) Under a nitrogen atmosphere, the FT-Bpin (1 eq), 2-bromopyridine (1.4 eq), and tetrakis(triphenylphosphine)palladium (0.03 eq) obtained in Example 1 were dissolved in 30 mL of a mixed solution of toluene and potassium carbonate aqueous solution (mixing volume ratio 1:1). The reaction mixture was reacted at 100 °C for 16 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, poured into 100 mL of water, and extracted three times with 40 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain ligand L-3.

[0083] 2) Under a nitrogen atmosphere, IrCl3 (1 eq) and ligand L-1 (2.1 eq) were dissolved in a mixed solvent of ethylene glycol ethyl ether and water (volume ratio 3:1), and the mixture was heated to 110 °C and stirred for 12 h. After the reaction was complete, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain an intermediate. The concentrated dark solid was dissolved in dichloromethane with t-BuOK (4 eq) and acetylacetone (8 eq), and stirred at 30 °C under a nitrogen atmosphere for 14 h. After the reaction was complete, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain a crude product. The crude product was separated by silica gel column chromatography to obtain target molecule 3 in 25% yield.

[0084] Example 10

[0085] This embodiment describes the synthesis steps of the target deep red to near-infrared iridium(III) complex 4 under different reaction conditions:

[0086] 1) Under a nitrogen atmosphere, FT-Bpin (1 eq), 2-bromobenzothiazole (1.2 eq), and tetraphenylphosphine palladium (0.03 eq) obtained in Example 1 were dissolved in 30 mL of a mixed solution of toluene and potassium carbonate aqueous solution (mixing volume ratio 2:1). The reaction mixture was reacted at 100 °C for 18 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, poured into 100 mL of water, and extracted three times with 40 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the crude product. The crude product was separated by silica gel column chromatography to obtain ligand L-4.

[0087] 2) Under a nitrogen atmosphere, IrCl3 (1 eq) and ligand L-1 (2.2 eq) were dissolved in a mixed solvent of ethylene glycol ethyl ether and water (volume ratio 3:1), and the mixture was heated to 110 °C and stirred for 16 h. After the reaction was complete, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain an intermediate. The concentrated dark solid was dissolved in dichloromethane with t-BuOK (5 eq) and acetylacetone (10 eq), and stirred at 30 °C for 12 h under a nitrogen atmosphere. After the reaction was complete, the reaction mixture was poured into 100 mL of water and extracted three times with 50 mL of dichloromethane. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain a crude product. The crude product was separated by silica gel column chromatography to obtain target molecule 4 in 18% yield.

Claims

1. A class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups, characterized in that, Select from the following three structures: 。 2. The method for preparing a type of deep red to near-infrared iridium(III) complex containing a fluoranthene group as described in claim 1, characterized in that, Under an inert gas atmosphere, IrCl3 and an organic ligand were dissolved in a mixed solvent of ethylene glycol ethyl ether and water until completely dissolved. The mixture was heated to 100–110 °C and stirred for 12–18 h. After the reaction was complete, the reaction mixture was poured into water and extracted with dichloromethane. The resulting organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the intermediate dimer. The concentrated intermediate dimer was then combined with… t Buok and acetylacetone were completely dissolved in dichloromethane and stirred at 25-30°C for 10-16 h under an inert atmosphere. After the reaction was completed, the reaction mixture was poured into water and extracted with dichloromethane. The resulting organic phase was dried with anhydrous sodium sulfate and concentrated under vacuum to obtain a crude product. The crude product was separated by silica gel column chromatography to obtain the target deep red to near-infrared iridium(III) complex. The molar ratio of IrCl3 to the organic ligand is 1: (2.1 to 2.2), and the volume ratio of the mixed solvent of ethylene glycol ethyl ether and water is 3:

1. The intermediate dimer and t -The molar ratio of BuOK and acetylacetone is 1:(3~5):(6~10).

3. The method for preparing a class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups according to claim 2, characterized in that, The organic ligand is prepared by the following method: Step 1: Synthesize the boron ester reaction intermediate containing fluoranthene groups, specifically as follows: Under an inert gas atmosphere, 3-bromofluoranthene, pinacol diboronate, 1,1-bis(diphenylphosphine)ferrocene palladium(II) dichloride and potassium acetate were completely dissolved in dioxane. The reaction mixture was reacted at 100–110 °C for 12–16 h. After the reaction was completed, the mixture was cooled to room temperature and poured into water. It was extracted with dichloromethane, dried over anhydrous sodium sulfate, and concentrated under vacuum to obtain the crude product. The crude product was then separated by silica gel column chromatography to obtain the borate ester reaction intermediate. Step 2: Synthesize organic ligands containing fluoranthene groups. The specific steps are as follows: Under an inert gas atmosphere, the borate ester reaction intermediate obtained in step one, the halogenated aromatic fused ring, and tetra-triphenylphosphine palladium were completely dissolved in a mixed solution of toluene and potassium carbonate aqueous solution. The reaction mixture was reacted at 100–110 °C for 16–18 h under inert gas protection. After the reaction was completed, the mixture was cooled to room temperature and poured into water. It was extracted with dichloromethane, and the organic phase was dried with anhydrous sodium sulfate. The crude product obtained by vacuum concentration was separated by silica gel column chromatography to obtain the synthesized organic ligand containing fluoranthene group.

4. The method for preparing a class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups according to claim 3, characterized in that, The inert gases are either nitrogen or argon.

5. The method for preparing a class of deep red to near-infrared iridium(III) complexes containing fluoranthene groups according to claim 3, characterized in that, In step one, the molar ratio of 3-bromofluoranthene, pinacol diboronate, 1,1-bis(diphenylphosphine)ferrocene palladium(II) dichloride and potassium acetate is 1 : (1.2 ~ 1.5) : (0.03 ~ 0.05) :

3.

6. The method for preparing a type of deep red to near-infrared iridium(III) complex containing a fluoranthene group according to claim 3, characterized in that, In step two, the molar ratio of the borate ester reaction intermediate, the halogenated aromatic fused ring, and tetraphenylphosphine palladium is 1: (1.2-1.5): (0.03-0.05). The volume ratio of the mixed solution of toluene and potassium carbonate aqueous solution is (1-3):1; In step two, the halogenated aromatic fused ring is 1-chloroisoquinoline, 2-chloroquinoline, or 2-bromobenzothiazole.

7. The application of the deep red to near-infrared iridium(III) complexes containing fluoranthene groups according to claim 1, characterized in that, Organic light-emitting materials used as the light-emitting layer in OLED devices.

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