An organic near-infrared Ⅱ region light-emitting material based on 3-oxo-3H-benzanthracene-1,2-dicarbonitrile, a preparation method and application thereof

Abstract

The application relates to the technical field of organic light emission, and discloses an organic near-infrared II region light-emitting material based on 3-oxo-3H-benzanthracene-1,2-dicyan and a preparation method and application thereof; the molecular structure general formula of the organic near-infrared II region light-emitting material is shown as I: formula I. The photoluminescence maximum emission wavelength of the near-infrared light-emitting material of the application realizes near-infrared II region light emission over 1100 nm, and a microsecond level delay lifetime is measured, the near-infrared light-emitting material has the property of thermal activated delayed fluorescence (TADF), and has wide application in the fields of organic electroluminescent displays, biological imaging, biological medical treatment and the like.

Description

Technical Field

[0001] This invention relates to the field of organic light-emitting technology, specifically to an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile, its preparation method, and its application. Background Technology

[0002] Near-infrared organic light-emitting diodes (NIR-OLEDs), as an emerging organic optoelectronic technology, have shown broad application potential in the near-infrared spectral region with high tissue penetration depth (especially the near-infrared II region window above 1000 nm). In this field, material systems based on the thermally activated delayed fluorescence (TADF) mechanism have attracted much attention because they can theoretically achieve 100% exciton utilization. However, the realization of near-infrared II emission faces severe challenges, among which the scarcity of strong acceptor units is the core bottleneck restricting material innovation.

[0003] Near-infrared II fluorescence imaging has garnered increasing attention in biomedical research due to its higher tissue penetration, lower autofluorescence in biological tissues, and higher signal-to-noise ratio. However, achieving efficient near-infrared II electroluminescence is particularly challenging in the OLED field. As the emission wavelength redshifts beyond 900 nm, the bandgap law leads to a sharp increase in the probability of nonradiative transitions, resulting in a significant decrease in fluorescence quantum yield. Furthermore, in the 1000-1700 nm wavelength range, the design of material systems faces greater limitations, and the molecular engineering of donor-acceptor structures is constrained by intrinsic energy level matching limitations.

[0004] Currently, the development of near-infrared TADF materials is limited by the availability of structurally simple strong acceptor units. Aside from a limited number of traditional systems such as acenaphthene and anthraquinone cyanopyrazines, the development of novel strong acceptor cores has progressed slowly. Existing acceptor structures generally suffer from limited spectral coverage or insufficient chemical stability when addressing near-infrared II emission requirements.

[0005] Developing novel near-infrared II region TADF materials has significant scientific value and practical implications. At the basic research level, it helps deepen the understanding of excited-state modulation mechanisms and promotes breakthroughs in the bandgap law limit. At the application level, high-efficiency near-infrared II region OLED devices will provide innovative solutions for fields such as bioimaging, medical diagnostics, and phototherapy.

[0006] Therefore, this invention proposes an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile, its preparation method, and its application. Summary of the Invention

[0007] To address the problems in related technologies, this invention proposes an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dinitrile, its preparation method, and its application, in order to overcome the aforementioned technical problems existing in the prior art.

[0008] This invention constructs a novel near-infrared II region TADF material based on 3-oxo-3H-benzanthracene-1,2-dionitrile with a DA molecular structure. By utilizing the strong electron-withdrawing ability of the 3-oxo-3H-benzanthracene-1,2-dionitrile acceptor, as well as oxygen-bridged triphenylamine, indole-quinoxalin-phenazine and its derivatives, near-infrared II region TADF materials with emission exceeding 1100 nm are achieved.

[0009] Therefore, the specific technical solution adopted by the present invention is as follows: According to a first aspect of the present invention, an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dianitron is provided, the general molecular structure of the organic near-infrared II region luminescent material being shown in Figure I:

[0010] Formula I Wherein, the donor D unit is an oxygen-bridged triphenylamine, indo-quinoxalin-phenazine, or a derivative thereof, and can be independently selected from any of the following formulas: .

[0011] The preferred structures of organic near-infrared II region luminescent materials based on 3-oxo-3H-benzanthracene-1,2-dionitrile are as follows; these compounds are only representative examples: .

[0012] Preferably, the donor units in the organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile are tert-butyloxy-bridged triphenylamine and tert-butylindoloquinoxolinophenazine, with molecular structural formulas named Z-1 or Z-2, respectively. .

[0013] According to a second aspect of the present invention, a method for preparing an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile is provided for preparing the above-mentioned organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile, the preparation method comprising the following steps:

[0014] Step S1: Using 9-bromoanthraquinone as a starting material, intermediate I is obtained by C-CC coupling reaction with donor D unit; Step S2: Intermediate I and malononitrile react in a reaction solvent via Knoevenagel reaction to obtain intermediate II; Step S3: Intermediate II undergoes a rearrangement reaction in an alkaline solvent to obtain the organic near-infrared II region luminescent material.

[0015] In step S1, the CC coupling reaction used to prepare intermediate I is the Suzuki coupling reaction and the Stille coupling reaction; in step S2, the reaction solvent for preparing intermediate II is a low polar aprotic solvent, and the low polar aprotic solvent is any one or a mixture of hexane, cyclohexane, carbon tetrachloride, benzene, toluene, m-xylene, etc.; in step S3, the base for preparing the organic near-infrared II region luminescent material is any one or a combination of sodium carbonate, potassium carbonate, cesium carbonate, sodium hydroxide, potassium hydroxide, sodium tert-butoxide, potassium tert-butoxide, etc., and the reaction temperature of the rearrangement reaction is 30~70℃.

[0016] According to a third aspect of the present invention, an application of an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile is provided in organic electroluminescent displays, bioimaging and biomedicine.

[0017] Compared with the prior art, the present invention provides an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile, its preparation method and application, which has the following beneficial effects: (1) This invention synthesizes 3-oxo-3H-benzanthracene-1,2-dinitrile acceptor unit for the first time and uses it in the molecular construction of organic near-infrared luminescent materials, providing a new strong acceptor unit for organic near-infrared TADF.

[0018] (2) Through simple and reasonable molecular construction, this invention designs and synthesizes a class of DA-type near-infrared TADF materials with 3-oxo-3H-benzanthracene-1,2-dionitrile as acceptor and oxygen-bridged triphenylamine, indole-quinoxalin-phenazine and its derivatives as donors, and obtains photoluminescence with emission peaks exceeding 1100 nm, realizing near-infrared II region luminescence.

[0019] (3) This invention provides a universal and feasible synthesis route that is simple and easy to synthesize. The photoluminescence of this type of near-infrared luminescent material achieves a maximum emission wavelength of over 1100 nm in the near-infrared II region, and the measured delay lifetime is in the microsecond range, exhibiting the properties of thermally activated delayed fluorescence (TADF). Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 The figure shows the 1H NMR spectrum of raw material R1 prepared according to Example 1 of the present invention, where 1.57 ppm is the water peak. Figure 2 The figure shows the 1H NMR spectrum of the raw material R2 prepared according to Example 1 of the present invention. In the figure, 7.19, 7.09, and 7.07 ppm are the solvent peaks of deuterated toluene. Figure 3 This is the hydrogen NMR spectrum of intermediate M1 obtained according to Example 1 of the present invention; Figure 4 This is the hydrogen NMR spectrum of intermediate M2 obtained according to Example 1 of the present invention; Figure 5 This is the 1H NMR spectrum of intermediate M3 obtained according to Example 1 of the present invention; Figure 6 The figure shows the 1H NMR spectrum of intermediate M4 prepared according to Example 1 of the present invention, where 7.19, 7.09, and 7.07 ppm are solvent peaks of deuterated toluene. Figure 7 The figure shows the 1H NMR spectrum of intermediate M5 prepared according to Example 1 of the present invention, where 5.30 ppm is the solvent peak of dichloromethane. Figure 8 The figure shows the 1H NMR spectrum of intermediate M6 prepared according to Example 1 of the present invention, where 5.29 ppm is the solvent peak of dichloromethane. Figure 9 This is the 1H NMR spectrum of compound Z-1 obtained according to Example 1 of the present invention; Figure 10 This is the carbon NMR spectrum of compound Z-1 obtained according to Example 1 of the present invention; Figure 11 This is the time-of-flight mass spectrum of compound Z-1 obtained according to Example 1 of the present invention; Figure 12 This is the 1H NMR spectrum of compound Z-2 obtained according to Example 1 of the present invention; Figure 13 This is the carbon NMR spectrum of compound Z-2 obtained according to Example 1 of the present invention; Figure 14 This is the time-of-flight mass spectrum of compound Z-2 obtained according to Example 1 of the present invention; Figure 15 This is a thermogravimetric curve of compounds Z-1 and Z-2 obtained according to Example 1 of the present invention; Figure 16 The ultraviolet absorption (in toluene Tol) and photoluminescence spectra (in n-hexane Hex and toluene Tol) of compound Z-1 prepared according to Example 1 of the present invention are shown. Figure 17The ultraviolet absorption (in toluene Tol) and photoluminescence spectra (in n-hexane Hex and toluene Tol) of compound Z-2 prepared according to Example 1 of the present invention are shown. Figure 18 This is the delayed lifetime spectrum of compound Z-1 prepared according to Example 1 of the present invention. In the figure, Decay represents the delay, IRF represents the blank, and FIT represents the fitted. Figure 19 This is the extended lifetime spectrum of compound Z-2 prepared according to Example 1 of the present invention. In the figure, Decay represents delay, IRF represents blank, and FIT represents fitting. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1 Synthetic schemes for organic near-infrared II region luminescent materials Z-1 and Z-2 based on 3-oxo-3H-benzanthracene-1,2-dionitrile are presented below. The raw material R3, catalyst, reagents, and solvent were all purchased commercially. Raw materials R1 and R2 were synthesized according to patent publications CN121021551A and CN119462674A, respectively. The synthetic routes for compounds Z-1 and Z-2 are as follows:

[0023] Synthesis of compound M1 Under nitrogen protection, the system was repeatedly evacuated and purged with nitrogen three times to ensure an oxygen-free environment. The following reactants were added sequentially to a dry 200 mL single-necked flask: reactant R1 (5.34 g, 11.49 mmol, 1.0 eq), pinacol diborate (3.50 g, 13.79 mmol, 1.2 eq), potassium acetate (KOAc, 4.51 g, 45.96 mmol, 4.0 eq), and catalyst Pd(dppf)Cl2 (252 mg, 0.35 mmol, 0.03 eq). Then, 30 mL of anhydrous toluene was added as a solvent. The mixture was gently shaken under a nitrogen flow to initially mix the solid reagents. A condenser was installed in the flask, and nitrogen was continuously introduced. The flask was placed in an oil bath and slowly heated to 110 °C, maintaining a stable reflux state for the reaction mixture. The mixture was stirred continuously for 24 hours, during which time the reaction progress was monitored periodically by thin-layer chromatography (TLC) using a petroleum ether / ethyl acetate mixture as the developing solvent. After the reaction was completed, the system was cooled to room temperature, the reaction solution was transferred to a separatory funnel, extracted three times with ethyl acetate, the organic phases were combined and washed with saturated brine, the organic layer was separated and dried with anhydrous sodium sulfate, filtered and the solvent was removed by rotary evaporation to obtain the crude product, and finally purified by column chromatography (with silica gel as the stationary phase and petroleum ether / ethyl acetate gradient elution) to obtain 5.06 g of white powder product, with a yield of 86.1%. 1 H NMR (400 MHz, CDCl3) δ7.37 (s, 2H), 6.91 (s, 4H), 6.81 (d,J= 8.4 Hz, 2H), 1.31 (s,12H), 1.28 (s, 18H).

[0024] Synthesis of compound M2 In a 100 mL two-necked flask, one neck was sealed with a sealing film and punctured with a needle to maintain a slight positive pressure. Nitrogen gas was then continuously introduced through the other neck for about 10 minutes to displace the air inside the flask. Reactants M1 (2.02 g, 6.50 mmol, 1.1 eq), R3 (3.32 g, 6.50 mmol, 1.0 eq), potassium carbonate (3.59 g, 26 mmol, 4.0 eq), and catalyst Pd(PPh3)4 (225.42 mg, 0.20 mmol, 0.03 eq) were then added sequentially. A pre-mixed and degassed mixture of tetrahydrofuran and deionized water (3:1 volume ratio) was added. A condenser was installed and a nitrogen atmosphere was maintained. The reaction system was placed in an oil bath preheated to 75°C and refluxed for 24 hours with continuous stirring. During this period, samples were taken periodically and the reaction progress was monitored by TLC (using an appropriately polar eluent). After the reaction was completed, the mixture was cooled to room temperature, transferred to a separatory funnel, extracted three times with ethyl acetate, the organic phases were combined and washed with saturated brine, dried over anhydrous sodium sulfate and filtered, the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product, and finally purified by silica gel column chromatography (eluting with petroleum ether / ethyl acetate gradient) to obtain 2.21 g of dark red solid product, with a yield of 55.23%. 1 H NMR (400 MHz, CDCl3)δ9.17 (d,J= 8.5 Hz, 1H), 8.08 (dd,J=17.5, 8.8 Hz, 2H), 7.98 (d,J= 6.6 Hz, 1H), 7.82 – 7.74 (m, 1H), 7.67 – 7.54(m, 2H), 7.26 (d,J= 8.5 Hz, 2H), 6.94 (d,J= 8.8 Hz, 2H), 6.89 (s, 2H), 6.54(s, 2H), 1.24 (s, 18H).

[0025] Synthesis of compound M3 In a 100 mL two-necked flask, one neck was sealed with a sealing film and punctured with a needle to allow gas exchange. Nitrogen gas was introduced through the other neck for approximately 10 minutes to fully displace the air inside the flask. Subsequently, reactants M2 (2.46 g, 4 mmol, 1.0 eq) and malononitrile (396 mg, 6 mmol, 1.5 eq) were added sequentially under a nitrogen atmosphere. 30 mL of a pre-degassed mixture of tetrahydrofuran and acetonitrile (3:1 v / v) was injected. A condenser was installed and a weak nitrogen flow was maintained. The reaction system was placed in an oil bath and slowly heated to 90 °C, kept under stable reflux, and stirred continuously for 12 hours. The reaction progress was monitored by thin-layer chromatography (TLC) during this period. After the reaction was completed, the mixture was cooled to room temperature, transferred to a separatory funnel, and extracted multiple times with ethyl acetate. The organic phases were combined and washed successively with deionized water and saturated brine. After drying with anhydrous sodium sulfate, the mixture was filtered, and the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. Finally, the crude product was purified by column chromatography (using a gradient elution system with an eluent of appropriate polarity) to obtain 2.22 g of grayish-brown solid product, with a yield of 83.62%. 1 H NMR (600 MHz, CDCl3)δ9.24 (d,J= 8.5Hz, 1H), 8.53 (d,J= 6.9 Hz, 1H), 8.14 (dd,J= 8.8, 4.1 Hz, 2H), 7.90–7.85 (m,1H), 7.72–7.64 (m, 2H), 7.34 (d,J= 8.5 Hz, 2H), 7.02 (d,J= 8.5 Hz, 2H), 6.97(s, 2H), 6.60 (s, 2H), 1.32 (s, 18H).

[0026] Synthesis of compound Z-1 In a 100 mL two-necked flask, one neck was sealed with a sealing film and punctured with a needle. The air inside the flask was completely replaced by repeated vacuuming and nitrogen purging three times. Then, under a nitrogen atmosphere, reactant M3 (1.33 g, 2 mmol, 1.0 eq) and catalytic amounts of potassium carbonate (27.6 mg, 0.2 mmol, 0.1 eq) were added sequentially. 30 mL of a pre-degassed mixture of tetrahydrofuran and acetonitrile (3:1 volume ratio) was injected. A condenser was installed and nitrogen pressure was maintained. The reaction system was placed in an oil bath and slowly heated to 90 °C, kept under stable reflux, and continuously stirred for 2 hours. The reaction progress was closely monitored by thin-layer chromatography (TLC) to determine completion. After the reaction was completed, the mixture was cooled to room temperature, transferred to a separatory funnel, and extracted multiple times with ethyl acetate. The organic phases were combined and washed successively with deionized water and saturated brine. After drying with anhydrous sodium sulfate, the mixture was filtered, and the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. Finally, the crude product was purified by silica gel column chromatography (using a gradient elution system with an appropriate polarity) to obtain 0.91 g of a purple-red solid product, with a yield of 68.05%. 1 H NMR (400 MHz, CD2Cl2) δ10.09 (d,J= 9.0 Hz, 1H), 8.52 (d,J= 7.1 Hz, 1H), 8.40 (d,J= 8.7 Hz,1H), 8.06 (d,J= 8.6 Hz,1H), 7.98 – 7.90 (m, 1H), 7.72 – 7.59 (m, 2H), 7.26(d,J= 8.5 Hz, 2H), 6.96 (d,J= 8.5 Hz, 2H), 6.89 (s, 2H), 6.52 (s, 2H), 1.22(s, 18H). 13 C NMR (151 MHz, CDCl3) δ 177.87, 150.97, 146.61, 145.15, 144.25,137.49, 135.99, 133.74, 133.52, 130.86, 130.09, 128.32, 127.28, 127.24,127.19, 126.29, 125.95, 125.08, 124.71, 122.21, 121.31, 120.98, 120.01,119.67, 113.88, 113.35, 112.85, 112.57, 112.10, 33.42, 30.19. MALDI-TOF MS(mass m / z): 663.25[H]+. Calcd for C 45 H 33N3O3: 643.25.

[0027] Synthesis of compound M4 Under nitrogen protection, a dry 100 mL single-necked flask was subjected to three cycles of evacuation and nitrogen purging to completely displace air. Subsequently, under a continuous nitrogen flow, compound R2 (8.35 g, 11.49 mmol, 1.0 eq), pinacol diborate (3.50 g, 13.79 mmol, 1.2 eq), potassium acetate (KOAc, 4.51 g, 45.96 mmol, 4.0 eq), and catalyst Pd(dppf)Cl (252 mg, 0.35 mmol, 0.03 eq) were added sequentially. 30 mL of anhydrous toluene was added as solvent, a condenser was installed, and the reaction system was placed in an oil bath preheated to 110 °C under a nitrogen atmosphere. The mixture was vigorously stirred and refluxed for 24 hours, during which the reaction progress was monitored by thin-layer chromatography (TLC). After the reaction was completed, the mixture was cooled to room temperature, transferred to a separatory funnel, extracted three times with ethyl acetate, the organic phases were combined and washed with saturated brine, dried over anhydrous sodium sulfate and filtered, the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product, and finally purified by silica gel column chromatography (eluting with petroleum ether / ethyl acetate gradient) to obtain 1.62 g of bright yellow solid product, with a yield of 75.9%. 1 H NMR (400 MHz,Tol)δ8.12 (d,J= 3.6 Hz, 4H), 7.99 (d,J= 8.8 Hz, 2H), 7.67(s, 2H), 7.59 (s,2H), 7.12 (s, 2H), 1.43 (s, 18H), 1.36 (s, 18H), 1.23 (s, 12H).

[0028] Synthesis of compound M5 In a 100 mL two-necked flask, one neck was sealed with a sealing film and a syringe needle was inserted to maintain ventilation. Nitrogen gas was then continuously introduced through the other neck to completely replace the air inside the flask. Under a stable nitrogen atmosphere, reactants M4 (2.02 g, 6.50 mmol, 1.1 eq), R3 (3.32 g, 6.50 mmol, 1.0 eq), potassium carbonate (3.59 g, 26 mmol, 4.0 eq), and catalyst Pd(PPh3)4 (225.42 mg, 0.20 mmol, 0.03 eq) were added sequentially to the reaction flask. Next, 30 mL of a mixed solvent of tetrahydrofuran and deionized water (volume ratio 3:1), pre-degassed by bubbling under nitrogen, was injected. A condenser was installed, and the reaction system was placed in an oil bath under a continuous nitrogen flow. The temperature was slowly increased to 75 °C, and the mixture was stirred and refluxed for 24 hours. During the reaction, samples were taken periodically to monitor the reaction progress using thin-layer chromatography (TLC). After the reaction was completed, the mixture was cooled to room temperature, transferred to a separatory funnel, and extracted three times with ethyl acetate. The combined organic phases were washed successively with deionized water and saturated brine, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. Finally, the crude product was purified by silica gel column chromatography (using a petroleum ether / ethyl acetate system for gradient elution) to obtain 2.21 g of a dark red solid product, with a yield of 55.23%. 1 H NMR (400 MHz, CDCl3)δ9.17 (d,J= 8.5Hz, 1H), 8.08 (dd,J= 17.5, 8.8Hz, 2H), 7.98 (d,J= 6.6 Hz, 1H), 7.82 – 7.74 (m, 1H), 7.67 – 7.54 (m, 2H),7.26 (d,J= 8.5 Hz, 2H), 6.94 (d,J= 8.8 Hz, 2H), 6.89 (s, 2H), 6.54 (s, 2H),1.24 (s, 18H).

[0029] Synthesis of compound M6 In a 100 mL two-necked flask, one neck was sealed with a sealing film and punctured with a syringe needle to maintain aeration balance. Nitrogen gas was then introduced through the other neck for approximately 15 minutes of bubbling purging to completely displace the air in the reactor. Under continuous positive pressure nitrogen flow, reactant M5 (3.50 g, 4 mmol, 1.0 eq) and malononitrile (396 mg, 6 mmol, 1.5 eq) were added sequentially. Next, 30 mL of a pre-anhydrous tetrahydrofuran / acetonitrile mixture (3:1 volume ratio) degassed with nitrogen bubbling was injected. A spherical condenser was installed, and the system was placed in an oil bath preheated to 90°C. The mixture was kept under stable reflux and continuously magnetically stirred for 12 hours, during which the consumption of reactants was monitored by thin-layer chromatography (TLC). After the reaction was complete, the mixture was allowed to cool naturally to room temperature, transferred to a separatory funnel, and extracted three times with ethyl acetate. The combined organic phases were washed successively with small amounts of deionized water and saturated brine, dried over anhydrous sodium sulfate, and filtered. The solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. Finally, the crude product was purified by silica gel column chromatography (using petroleum ether / ethyl acetate as eluent for gradient elution) to give 3.00 g of a grayish-brown solid product, with a yield of 81.14%. 1 H NMR (600 MHz, CH2Cl2)δ9.11 (s, 1H), 8.36 (s, 1H), 8.14 (s, 2H), 7.96 (s, 2H), 7.61 (s, 2H), 7.48 (s, 4H), 7.30 (d,J=24.8 Hz, 5H), 7.16 (s, 2H), 1.42 (s, 18H), 1.30 (s, 18H).

[0030] Synthesis of compound Z-2 In a 100 mL two-necked flask, one neck was sealed with a sealing film and punctured with a needle to maintain a slight positive pressure. The reaction system was then evacuated and purged with nitrogen three times to ensure an oxygen-free environment. Under continuous nitrogen protection, reactant M8-2 (1.85 g, 2 mmol, 1.0 eq) and catalytic amounts of potassium carbonate (27.6 mg, 0.2 mmol, 0.1 eq) were added sequentially to the flask. 30 mL of a pre-degassed anhydrous tetrahydrofuran and acetonitrile mixture (3:1 volume ratio) was added, a condenser was installed, and the reaction system was placed in an oil bath preheated to 90 °C under a nitrogen atmosphere. The mixture was vigorously stirred magnetically and refluxed for 2 hours, during which the reaction progress was monitored by thin-layer chromatography (TLC) until the reactants were largely consumed. After the reaction was complete, the mixture was cooled to room temperature and transferred to a separatory funnel. The aqueous phase was extracted multiple times with ethyl acetate. The combined organic phases were washed successively with deionized water and saturated brine, dried over anhydrous sodium sulfate, and filtered. The solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. Finally, the product was purified by silica gel column chromatography (eluting with a petroleum ether / ethyl acetate gradient) to obtain 1.22 g of a purple-red solid product, with a yield of 65.72%. This reaction efficiently achieved the functional group transformation of the target molecule under weak base catalysis, and the product structure was confirmed by 1H NMR spectroscopy. 1 H NMR (400 MHz, CD2Cl2)δ10.03 (d,J= 9.2 Hz, 1H), 8.38 (dd,J=12.2, 7.7 Hz, 2H), 8.07 (d,J= 8.2 Hz, 1H), 7.93 (s, 2H), 7.65 (s, 3H), 7.56(t,J= 7.7 Hz, 1H), 7.52 – 7.40 (m, 3H), 7.17 (s, 4H), 7.03 (d,J= 7.3 Hz, 2H), 1.44 (s, 18H), 1.25 (s, 18H). 13C NMR (151 MHz, CD2Cl2) δ 178.89, 151.86,147.59, 144.86, 138.43, 137.26, 135.45, 134.69, 134.55, 132.82, 132.77,132.01, 129.34, 128.42, 128.31, 128.06, 127.40, 127.15, 126.17, 126.06,124.86, 124.10, 123.88, 123.21, 123.09, 122.00, 120.87, 117.62, 114.06,113.45, 112.98, 111.91, 110.14, 107.14, 35.45, 34.72, 31.87,31.57. MALDI-TOFMS (mass m / z): 921.44[H]+. Calcd for C 65 H 55 N5O:921.44.

[0031] Figure 1-14 The 1H NMR spectrum of the intermediate and the 1H NMR, 1C NMR, and 1M NMR ...

[0032] Example 2 TG testing of an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile Compounds Z-1 and Z-2, 5 mg each, were weighed and evenly spread in a high-temperature resistant crucible. The crucible was then placed on the sample holder of a thermobalance and heated from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere. The instrument recorded and plotted the thermogravimetric (TG) curves, i.e., the mass-temperature / time curves, in real time. Figure 15 As shown in the figure. By analyzing the TG curves, the thermal decomposition temperatures of samples Z-1 and Z-2 were determined to be 401.2℃ and 462.1℃, respectively.

[0033] Example 3 UV Testing of Organic Near-Infrared Region II Luminescent Materials Based on 3-O-3H-Benzanthracene-1,2-Dinitrile Compounds Z-1 and Z-2 were dissolved in toluene solution, and thin films of Z-1 and Z-2 were prepared by spin coating. The UV-Vis absorption spectra of the thin films were then measured. Figures 16-17It can be seen that the UV-Vis absorption spectra of compounds Z-1 and Z-2 in the thin film have three absorption peaks: the absorption band of compound Z-1 around 320-400 nm is attributed to π-π transition, the absorption band around 430-480 nm is the CT+LE state, and the absorption band around 620-750 nm is attributed to intramolecular charge transfer (ICT). Similarly, the absorption band of compound Z-2 around 320-420 nm is attributed to π-π transition, the absorption band around 430-590 nm is the CT+LE state, and the absorption band around 600-800 nm is attributed to intramolecular charge transfer (ICT).

[0034] Example 4 A hexane solution PL test of an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile Photoluminescence performance testing of compounds Z-1 and Z-2 in Example 1. Compounds Z-1 and Z-2 were dissolved in n-hexane to prepare 10⁻⁵ M solutions, and the photoluminescence spectra of these solutions were measured. Figure 16-17 As shown, under photoexcitation, all compounds are in the near-infrared region. Among them, compound Z-1 has a maximum emission peak of 847 nm in n-hexane solution, and compound Z-2 has an emission peak of 892 nm in n-hexane solution, thus meeting the near-infrared requirement.

[0035] Example 5 Toluene PL testing based on an organic near-infrared II region luminescent material of 3-oxo-3H-benzanthracene-1,2-dionitrile Photoluminescence properties of compounds Z-1 and Z-2 in Example 1 were tested. Compounds Z-1 and Z-2 were dissolved in toluene to prepare a 10... -5 Solution M was tested, and its photoluminescence spectrum was measured. Figure 16-17 As shown, under photoexcitation, all compounds are in the near-infrared region. Among them, compound Z-1 has a maximum emission peak of 1010 nm in toluene solution, and compound Z-2 has an emission peak of 1130 nm in toluene solution, which meets the requirement of near-infrared II region emission.

[0036] Example 6 Delayed fluorescence lifetime test of Z-1, an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile Compound Z-1 from Example 1 was doped into PMMA, and the delayed lifetime spectrum of its 10% wt doped film was tested. Figure 18 As shown. The fitted data shows a lifetime of 3.44 s, which, at the microsecond level, proves that Z-1 is a TADF material.

[0037] Example 7 Delayed fluorescence lifetime test of Z-2, an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile Compound Z-2 from Example 1 was doped into PMMA, and the delayed lifetime spectrum of its 10% wt doped film was tested. Figure 19 As shown. The fitted data shows a long lifetime of 2.50 s, which, at the microsecond level, proves that Z-2 is a TADF material.

[0038] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile, characterized in that, The general molecular structure formula of the organic near-infrared II region luminescent material is shown in Figure I: Equation I; Wherein, the donor D unit is an oxygen-bridged triphenylamine, indo-quinoxalinophenazine, or its derivatives, and can be independently selected from any of the following formulas: 。 2. The organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile according to claim 1, characterized in that, The molecular structural formula of the organic near-infrared II region luminescent material is any one of the following molecular formulas: 。 3. The organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile according to claim 2, characterized in that, The molecular structural formulas of the organic near-infrared II region luminescent material are Z-1 and Z-2: 。 4. The organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile according to claim 1, characterized in that, The doped film prepared by doping the organic near-infrared II region luminescent material in PMMA at a mass ratio of 10% showed a delay lifetime in the micrometer range.

5. The organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile according to claim 1, characterized in that, Photoluminescence with an emission peak exceeding 1100 nm was achieved in toluene solution.

6. A method for preparing an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile, used to achieve the preparation of the organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: ； Step S1: Using 9-bromoanthraquinone as a starting material, intermediate I is obtained by C-CC coupling reaction with donor D unit; In step S2, intermediate I and malononitrile react in a reaction solvent via Knoevenagel reaction to obtain intermediate II; Step S3: Intermediate II undergoes a rearrangement reaction in an alkaline solvent to obtain the organic near-infrared II region luminescent material.

7. The method for preparing an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile according to claim 6, characterized in that, In step S1, the CC coupling reactions used to prepare intermediate I are the Suzuki coupling reaction and the Stille coupling reaction.

8. The method for preparing an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile according to claim 6, characterized in that, In step S2, the reaction solvent for preparing intermediate II is a low-polarity aprotic solvent, and the low-polarity aprotic solvent is any one or a mixture of hexane, cyclohexane, carbon tetrachloride, benzene, toluene, and m-xylene.

9. The method for preparing an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile according to claim 6, characterized in that, In step S3, the base used to prepare the organic near-infrared II region luminescent material is any one or a combination of sodium carbonate, potassium carbonate, cesium carbonate, sodium hydroxide, potassium hydroxide, sodium tert-butoxide, and potassium tert-butoxide, and the reaction temperature of the rearrangement reaction is 30~70℃.

10. The application of an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile as described in any one of claims 1-5, or an organic near-infrared II region luminescent material based on 3-oxo-3H-benzanthracene-1,2-dionitrile prepared by any one of claims 6-9, in organic electroluminescent displays, bioimaging, and biomedicine.

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