Triplet photosensitizer molecule with near-infrared absorption and capable of efficiently generating singlet oxygen as well as preparation method and application of triplet photosensitizer molecule

Abstract

The invention relates to a triplet photosensitizer molecule with near-infrared absorption and capable of efficiently generating singlet oxygen and a preparation method and application thereof.In the nitrogen atmosphere, bilateral bromide of an A2 electron-withdrawing unit and unilateral tin compounds of D1 and D2 electron-donating units are heated in an anhydrous toluene system under catalysis of commercially available tetrakis (triphenylphosphine) palladium for Stille coupling reaction, and the triplet photosensitizer molecule with near-infrared absorption and capable of efficiently generating singlet oxygen is obtained. The reaction temperature is 100-140 DEG C, and the reaction time is 6-24 hours, so as to obtain an intermediate D1-A2-D2; under the nitrogen atmosphere, the D1-A2-D2 intermediate reacts with phosphorus oxychloride in an anhydrous DMF solution, the reaction temperature is 70-90 DEG C, the reaction time is 8-24 h, and a bilateral aldehyde group intermediate CHO-D1-A2-D2-CHO is obtained; in a nitrogen atmosphere, heating the CHO-D1-A2-D2-CHO intermediate, an A1 electron withdrawing unit and piperidine in a chloroform solution, and carrying out Knoevenagel condensation reaction at the reaction temperature of 50-65 DEG C for 8-24 hours, so as to obtain a product as shown in a formula (1); the triplet photosensitizer molecule provided by the invention is simple in structure, does not contain transition metal, and has good biocompatibility.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and in particular to a triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen, and a preparation method and application thereof. Background Art

[0002] In recent years, photodynamic therapy, as a new type of tumor treatment method, has the advantages of being non-invasive, easy to operate, good selectivity, and low toxic side effects, and has attracted widespread attention from scientists. Photodynamic therapy uses light to excite triplet photosensitizers enriched in tumor tissues, sensitizing oxygen molecules in the tissues to produce reactive oxygen species, thereby causing apoptosis and necrosis of tumor cells. Among them, the triplet photosensitizer reaches its singlet excited state after being excited by light, and generates a triplet excited state through the intersystem crossing process, which can undergo an intermolecular energy transfer process with oxygen molecules, produce singlet oxygen with high reactivity to oxidize biological components in cells, and then cause cell apoptosis and necrosis, achieving the purpose of treatment. In order to be better applied in biological therapy, a good triplet photosensitizer should have the following properties: low biological toxicity; efficient intersystem crossing ability; strong light absorption ability in the near-infrared band; long triplet excited state lifetime, etc. In particular, infrared light has a relatively deep penetration ability, which can penetrate biological tissues to achieve better photodynamic therapy effects. Therefore, efficient triplet photosensitizers with near-infrared light absorption have far-reaching significance for promoting the development of life sciences.

[0003] At present, triplet photosensitizers mainly include inorganic nanomaterials, porphyrin derivatives, transition metal complexes, cyanine dyes, fluoroboryl pyrrole derivatives, and other organic small molecules. Compared with inorganic nanomaterials and transition metal complexes, organic triplet photosensitizers have the advantages of high biocompatibility and good degradability, and their synthesis route is simple and inexpensive. However, in most reported studies (such as the article Heavy-atom-free π-twisted photosensitizers for fluorescence bioimaging and photodynamic therapy, DOI: 10.1039 / D4TB01014K), most of the efficient organic triplet photosensitizers have twisted structures, resulting in a short absorption wavelength, generally less than 600nm, which is difficult to penetrate deep into the skin to reach internal organs, thus limiting the tumor treatment site. Near-infrared light has a high penetration depth and is less damaging to biological tissues, but there are few types of organic triplet photosensitizers that absorb in the near-infrared light region, which limits the selection range of excitation light wavelengths in photodynamic therapy and its application.

[0004] Therefore, the development of biocompatible, efficient, organic triplet photosensitizers with near-infrared absorption has become an issue that needs to be studied and solved urgently. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a triplet photosensitizer molecule with near-infrared absorption and capable of efficiently generating singlet oxygen, as well as a preparation method and application thereof. Compared with traditional photosensitizers, the novel organic triplet photosensitizer has an efficient intersystem crossing process and a long triplet lifetime, can use near-infrared light irradiation to efficiently generate singlet oxygen, can realize near-infrared light-excited photodynamic therapy, and improve the tumor treatment effect.

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] A triplet photosensitizer molecule with near-infrared absorption and capable of efficiently generating singlet oxygen, the structural formula of which is shown in formula (1):

[0008]

[0009] In the formula (1), A1 and A2 are electron-withdrawing units, and D1 and D2 are electron-donating units.

[0010] Moreover, the electron-withdrawing unit A1 in the formula (1) is selected from any one of the structural formulas shown in the following formulas (2-1) to (2-4):

[0011]

[0012] In the formula (2-1) and the formula (2-2), X is selected from any one of the following groups: hydrogen, fluorine, chlorine, bromine, and iodine.

[0013] Moreover, in the formula (1), the electron donating units D1 and D2 are selected from any one of the same or different structural formulas shown in the following formulas (3-1) to (3-8):

[0014]

[0015] In the formula (3-1) to the formula (3-6), R1, R2, R3, and R4 are the same or different, and are independently selected from any one of the following groups: hydrogen, alkyl, alkoxy, alkylthio, and silane;

[0016] The alkyl, alkoxy, alkylthio and silane groups are straight or branched chains with 1 to 16 carbon atoms.

[0017] Moreover, in the formula (1), the electron-withdrawing unit A2 is selected from any of the structural formulas shown in the following formulas (4-1) to (4-5):

[0018]

[0019] In the formula (4-1) to the formula (4-4), R5 and R6 are the same or different, and are independently selected from any one of the following groups: hydrogen, alkyl, alkoxy, alkylthio;

[0020] The alkyl, alkoxy, alkylthio and silane groups are straight or branched chains with 1 to 16 carbon atoms.

[0021] Moreover, it is any one of the following structures (5-1) to (5-6):

[0022]

[0023] A method for preparing a triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen is characterized by the following steps:

[0024]

[0025] Furthermore, the following steps are included:

[0026] S1, under nitrogen atmosphere, the bilateral bromide of the electron-withdrawing unit A2 and the unilateral tin compounds of the electron-donating units D1 and D2 are heated in anhydrous toluene system under the catalysis of commercially available tetrakis(triphenylphosphine)palladium for Stille coupling reaction, the reaction temperature is 100-140°C, the reaction time is 6-24h, and the intermediate D1-A2-D2 is obtained;

[0027] S2. Under a nitrogen atmosphere, the D1-A2-D2 intermediate reacts with phosphorus oxychloride in anhydrous DMF solution at a reaction temperature of 70-90° C. for 8-24 h to obtain a bilateral aldehyde intermediate CHO-D1-A2-D2-CHO;

[0028] S3. Under a nitrogen atmosphere, the CHO-D1-A2-D2-CHO intermediate is heated with the A1 electron-withdrawing unit and piperidine in a chloroform solution to carry out a Knoevenagel condensation reaction at a reaction temperature of 50-65° C. for a reaction time of 8-24 h to obtain a product represented by formula (1).

[0029] Moreover, the molar ratio of the bilateral bromide, the unilateral tin compound, and tetrakis(triphenylphosphine)palladium is 1:2-2.5:0.05-0.2;

[0030] The molar ratio of the D1-A2-D2 intermediate to phosphorus oxychloride is 1:2-2.5:0.05-0.2;

[0031] The molar ratio of the CHO-D1-A2-D2-CHO intermediate to the A1 electron-withdrawing unit is 1:2-2.5:0.05-0.2;

[0032] In step S1, the reaction temperature is 110-120°C and the reaction time is 6-12h;

[0033] In step S2, the reaction temperature is 75-85°C and the reaction time is 12-18h;

[0034] In step S3, the reaction temperature is 55-60° C. and the reaction time is 12-18 h.

[0035] A triplet photosensitizer molecule with near-infrared absorption and capable of efficiently generating singlet oxygen, or its use as a singlet oxygen generating agent after being made into nanoparticles.

[0036] A triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen, or its use in photodynamic therapy after being made into nanoparticles.

[0037] The advantages and positive effects of the present invention are:

[0038] 1. The triplet photosensitizer molecule of the present invention has a simple structure, few synthesis steps, does not contain transition metals, is low in price and has good biocompatibility.

[0039] 2. The triplet photosensitizer molecule described in the present invention has a structure in which electron donors and electron acceptors are alternately connected, which can effectively red-shift the absorption spectrum, and the absorption spectrum of the molecule can reach the near-infrared region; by changing different electron donors and electron acceptors, the intersystem crossing and triplet quantum yield of the molecule are regulated, thereby extending the triplet lifetime and increasing the singlet oxygen yield. The molecule can produce singlet oxygen under near-infrared light irradiation, and has application prospects in photodynamic therapy.

[0040] 3. The near-infrared light excited by the triplet photosensitizer molecules described in the present invention has better biological tissue penetration than light in the ultraviolet and visible regions, and causes less damage to biological tissues. The material has the advantages of near-infrared absorption and high singlet oxygen yield, and has great application value for photodynamic therapy in vivo.

[0041] 4. The present invention proposes a design and synthesis strategy for an organic triplet photosensitizer molecule that does not contain transition metal elements and has near-infrared absorption. Compared with traditional photosensitizers, the new organic triplet photosensitizer has an efficient intersystem crossing process and a long triplet lifetime, can use near-infrared light irradiation to efficiently generate singlet oxygen, can achieve near-infrared light-excited photodynamic therapy, and improve the effect of tumor treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 5-1 and 5-2 are absorption spectra of the compounds of the present invention in chloroform solution.

[0043] Figure 2 This is a diagram of singlet oxygen generated in solution by formula (5-1) in an embodiment of the present invention.

[0044] Figure 3 This is a diagram of singlet oxygen generated in solution by formula (5-2) in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below by specific examples, which are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited by them. The materials mentioned above can be obtained from public commercial channels unless otherwise specified.

[0046] A method for preparing a triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen, comprising the following steps:

[0047]

[0048] Under nitrogen atmosphere, the bilateral bromide (1 equivalent) of the electron-withdrawing unit A2 and the unilateral tin compound (2.2 equivalents) of the electron-donating units D1 and D2 were heated in anhydrous toluene system for Stille coupling reaction under the catalysis of commercially available tetrakis(triphenylphosphine)palladium (0.1 equivalent) to obtain the intermediate D1-A2-D2;

[0049] Further, under nitrogen atmosphere, D1-A2-D2 intermediate (1 equivalent) and phosphorus oxychloride (10 equivalents) were reacted in anhydrous DMF solution to synthesize bilateral aldehyde intermediate CHO-D1-A2-D2-CHO;

[0050] Next, under a nitrogen atmosphere, the CHO-D1-A2-D2-CHO intermediate (1 equivalent) was heated with the A1 electron-withdrawing unit (4 equivalents) and piperidine (0.2 mL) in a chloroform solution to undergo a Knoevenagel condensation reaction to obtain the product of formula (1).

[0051] Example 1

[0052] A method for preparing a triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen, the present embodiment is the synthesis of an electron donor acceptor type triplet photosensitizer material formula (5-1), comprising the following steps:

[0053] The synthesis was carried out according to the following reaction equation:

[0054]

[0055] S1. Synthesis of intermediate 1: Under nitrogen protection, raw material 1 (5.5 g, 10 mmol) was dissolved in 200 mL of ethanol, and NaBH4 (3.03 g, 80 mmol) was added in batches under an ice-water bath, followed by stirring at room temperature for 2 h. After the reaction was completed, the solvent was distilled off under reduced pressure, and 100 mL of water was added. After extraction with dichloromethane three times, the organic phase was collected, dried over anhydrous sodium sulfate, and filtered, and the solvent was distilled off under reduced pressure to obtain a crude product, which was purified by column chromatography using a mixed solution of petroleum ether and dichloromethane in a volume ratio of 2:1 as an eluent to obtain a yellow oily product intermediate 1.

[0056] S2. Synthesis of intermediate 2: Under nitrogen protection, intermediate 1 (2.61 g, 5 mmol) was dissolved in 30 mL of glacial acetic acid, and 10 mL of sodium nitrite (0.41 g, 6 mmol) aqueous solution was added in an ice-water bath, followed by stirring at room temperature for 1 h. After the reaction was completed, the solvent was distilled off under reduced pressure, and 100 mL of water was added. After extraction with dichloromethane three times, the organic phase was collected, dried over anhydrous sodium sulfate, and filtered, and the solvent was distilled off under reduced pressure to obtain a crude product. The crude product was purified by column chromatography, and a mixed solution of ethanol and dichloromethane in a volume ratio of 1:50 was used as an eluent to obtain a colorless oily product intermediate 2.

[0057] S3. Synthesis of intermediate 3: Under nitrogen protection, intermediate 2 (2.13 g, 4 mmol), potassium carbonate (2.76 g, 20 mmol) and 1-bromo-2-butyloctane (3.0 g, 12 mmol) were added to 50 mL of DMF solution, and the reaction solution was stirred at 90 °C overnight. After the reaction was completed, the filtrate was filtered and collected, and the solvent was removed by distillation under reduced pressure. The crude product was purified by column chromatography, and a mixed solution of petroleum ether and dichloromethane in a volume ratio of 3:1 was used as an eluent to obtain a colorless oily product intermediate 3.

[0058] S4. Synthesis of intermediate 4: Under nitrogen protection, intermediate 3 (671 mg, 1 mmol), raw material 2 (1.32 g, 2.2 mmol), and tetrakis(triphenylphosphine)palladium (115.6 mg, 0.1 mmol) were added to 20 mL of dry toluene solution, and the mixture was stirred at 110°C for 12 h. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was poured into an aqueous potassium fluoride solution. The mixture was extracted three times with dichloromethane, and the organic phase was collected. After drying and filtering with anhydrous sodium sulfate, the solvent was removed by distillation under reduced pressure to obtain a crude product, which was purified by column chromatography using a mixed solution of ethanol and dichloromethane in a volume ratio of 1:8 as an eluent to obtain an orange oily product intermediate 4; wherein raw material 2 is tributyl(6-(2-butyloctyl)thieno[3,2-B]thiophen-2-yl)stannane.

[0059] S5. Synthesis of intermediate 5: Under nitrogen protection, intermediate 4 (677 mg, 0.6 mmol) was added to 20 mL of anhydrous DMF solution, phosphorus oxychloride (920 mg, 6 mmol) was added dropwise in an ice-water bath and stirring was continued for 1 h. The reaction solution was then heated to 80 °C and stirred overnight. After the reaction was completed, the reaction solution was poured into 100 mL of water, and a saturated aqueous sodium carbonate solution was added to adjust the pH to neutral. After extraction with dichloromethane three times, the organic phase was collected, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure to obtain a crude product, which was purified by column chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:2 as the eluent to obtain a red powder intermediate 5.

[0060] S6. Synthesis of formula (5-1): Under nitrogen protection, intermediate 5 (118 mg, 0.1 mmol), raw material 3 (92 mg, 0.4 mmol), and piperidine (0.2 mL) were added to 20 mL of chloroform solution, stirred at 60 °C overnight, cooled to room temperature after the reaction, and the solvent was removed by distillation under reduced pressure. 5 mL of chloroform was added to dissolve the mixture, and then poured into 50 mL of methanol. The crude product was filtered to obtain a crude product, which was purified by column chromatography using a mixture of petroleum ether and dichloromethane in a volume ratio of 1:2 as the eluent to obtain a dark blue product of formula (5-1); wherein the raw material 3 is 5,6-difluoro-3-(dicyanomethyl)indone.

[0061] Example 2

[0062] A method for preparing a triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen, the present embodiment is the synthesis of an electron donor acceptor type triplet photosensitizer material formula (5-2), comprising the following steps:

[0063] The synthesis was carried out according to the following reaction equation:

[0064]

[0065] S1. Synthesis of intermediate 6: Under nitrogen protection, intermediate 3 (671 mg, 1 mmol), raw material 4 (1.42 g, 2.2 mmol), and tetrakis(triphenylphosphine)palladium (115.6 mg, 0.1 mmol) were added to 20 mL of dry toluene solution, and the mixture was stirred at 110°C for 12 h. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was poured into an aqueous potassium fluoride solution. The mixture was extracted three times with dichloromethane, and the organic phase was collected. After drying and filtering with anhydrous sodium sulfate, the solvent was removed by distillation under reduced pressure to obtain a crude product, which was purified by column chromatography using ethanol and dichloromethane in a volume ratio of 1:8 as eluent to obtain an orange oily product intermediate 6; wherein raw material 4 is tributyl(6-(2-butyloctyl)selenopheno[3,2-B]thiophen-2-yl)stannane.

[0066] S2. Synthesis of intermediate 7: Under nitrogen protection, intermediate 6 (734 mg, 0.6 mmol) was added to 20 mL of anhydrous DMF solution, phosphorus oxychloride (920 mg, 6 mmol) was added dropwise in an ice-water bath and stirring was continued for 1 h. The reaction solution was then heated to 80 °C and stirred overnight. After the reaction was completed, the reaction solution was poured into 100 mL of water, and a saturated aqueous sodium carbonate solution was added to adjust the pH to neutral. After extraction with dichloromethane three times, the organic phase was collected, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure to obtain a crude product, which was purified by column chromatography using petroleum ether and dichloromethane in a volume ratio of 1:2 as eluent to obtain a red powder intermediate 7.

[0067] S3. Synthesis of formula (5-2): Under nitrogen protection, intermediate 7 (128 mg, 0.1 mmol), raw material 3 (92 mg, 0.4 mmol), and piperidine (0.2 mL) were added to 20 mL of chloroform solution and stirred at 60 °C overnight. After the reaction was completed, the mixture was cooled to room temperature and the solvent was removed by distillation under reduced pressure. 5 mL of chloroform was added to dissolve the mixture and then poured into 50 mL of methanol. The crude product was filtered to obtain a crude product, which was purified by column chromatography using petroleum ether and dichloromethane in a volume ratio of 1:2 as eluent to obtain a dark blue product of formula (5-2).

[0068] Example 3

[0069] The absorption spectrum data of the electron donor acceptor type triplet photosensitizer materials (5-1) and (5-2) synthesized in Example 1 and Example 2 in chloroform solution were measured using a visible light-ultraviolet absorption spectrometer. The absorption spectrum is as follows: Figure 1 As shown in the figure, it can be seen that the absorption wavelength range of the material in the organic solution is mainly 500-770nm, among which the maximum absorption peak of material formula (5-1) is 680nm, and the maximum absorption peak of material formula (5-2) is 695nm, indicating that the material has strong absorption in the visible and near-infrared light regions.

[0070] Example 4

[0071] The generation of singlet oxygen in the electron donor acceptor type triplet photosensitizer materials (5-1) and (5-2) synthesized in Example 1 and Example 2 is detected by using a singlet oxygen scavenger (DPBF), comprising the following steps:

[0072] S1. Prepare chloroform solutions of formula (5-1) and formula (5-2) respectively, use the chloroform solution of formula (5-1) as mother solution A1, and use the chloroform solution of formula (5-2) as mother solution A2. The concentrations of mother solution A1 and mother solution A2 are both 0.001 mmol / mL.

[0073] S2. Prepare a chloroform solution of DPBF with a concentration of 0.001 mmol / mL as mother solution B.

[0074] S3. Take 0.005 mL of mother solution A1, dilute it with chloroform solvent until the absorbance at 600 nm is about 0.2, then add mother solution B to make the absorbance at 415 nm about 1, and obtain a mixed solution containing formula (5-1) and DPBF.

[0075] S4. Take 0.005 mL of mother solution A2, dilute it with chloroform solvent until the absorbance at 600 nm is about 0.2, then add mother solution B to make the absorbance at 415 nm about 1, and obtain a mixed solution containing formula (5-2) and DPBF.

[0076] S5. Under light-proof conditions, irradiate the mixed solution containing formula (5-1) and DPBF and the mixed solution containing formula (5-2) and DPBF with 600nm light respectively, and detect the decrease in the DPBF absorption peak intensity when irradiated for 0 seconds, 30 seconds, 60 seconds, 90 seconds, 120 seconds, 150 seconds, 180 seconds, 210 seconds, and 240 seconds, so as to detect the singlet oxygen generation state.

[0077] The singlet oxygen generated by the electron donor acceptor type triplet photosensitizer material (5-1) in the solution is shown in the figure Figure 2 As shown in the figure, it can be seen that the DPBF absorption peak intensity at 415nm decreases from 1.00 to 0.95 within 240 seconds, indicating that the material formula (5-1) has the ability to generate singlet oxygen.

[0078] The singlet oxygen generated by the electron donor acceptor type triplet photosensitizer material (5-2) in the solution is shown in the figure Figure 3 As shown in the figure, it can be seen that the DPBF absorption peak intensity at 415nm drops from 1.14 to 0.58 within 240 seconds, indicating that material formula (5-2) has the ability to generate singlet oxygen. By comparison, it is shown that the efficiency of material formula (5-2) in generating singlet oxygen is 11.2 times that of formula (5-1), and it can be used as a triplet photosensitizer with near-infrared absorption and the ability to efficiently generate singlet oxygen.

[0079] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A triplet photosensitizer molecule with near-infrared absorption and capable of efficiently generating singlet oxygen, characterized in that: The structural formula is shown in formula (1): In the formula (1), A1 and A2 are electron-withdrawing units, and D1 and D2 are electron-donating units.

2. The triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen according to claim 1, characterized in that: The electron-withdrawing unit A1 in the formula (1) is selected from any one of the following structural formulas (2-1) to (2-4): In the formula (2-1) and the formula (2-2), X is selected from any one of the following groups: hydrogen, fluorine, chlorine, bromine, and iodine.

3. The triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen according to claim 1, characterized in that: In the formula (1), the electron donating units D1 and D2 are selected from any one of the following structural formulas (3-1) to (3-8), which are the same or different: In the formula (3-1) to the formula (3-6), R1, R2, R3, and R4 are the same or different, and are independently selected from any one of the following groups: hydrogen, alkyl, alkoxy, alkylthio, and silane; The alkyl, alkoxy, alkylthio and silane groups are straight or branched chains with 1 to 16 carbon atoms.

4. The triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen according to claim 1, characterized in that: In the formula (1), the electron-withdrawing unit A2 is selected from any one of the structural formulas shown in the following formulas (4-1) to (4-5): In the formula (4-1) to the formula (4-4), R5 and R6 are the same or different, and are independently selected from any one of the following groups: hydrogen, alkyl, alkoxy, alkylthio; The alkyl, alkoxy, alkylthio and silane groups are straight or branched chains with 1 to 16 carbon atoms.

5. The triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen according to claim 1, characterized in that: Any one of the following structures (5-1) to (5-6):

6. A method for preparing a triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen as claimed in claim 1, characterized in that: Here are the steps:

7. The method for preparing a triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen according to claim 6, characterized in that: The steps include: S1, under nitrogen atmosphere, the bilateral bromide of the electron-withdrawing unit A2 and the unilateral tin compounds of the electron-donating units D1 and D2 are heated in anhydrous toluene system under the catalysis of commercially available tetrakis(triphenylphosphine)palladium for Stille coupling reaction, the reaction temperature is 100-140°C, the reaction time is 6-24h, and the intermediate D1-A2-D2 is obtained; S2. Under a nitrogen atmosphere, the D1-A2-D2 intermediate reacts with phosphorus oxychloride in anhydrous DMF solution at a reaction temperature of 70-90° C. for 8-24 h to obtain a bilateral aldehyde intermediate CHO-D1-A2-D2-CHO; S3. Under a nitrogen atmosphere, the CHO-D1-A2-D2-CHO intermediate is heated with the A1 electron-withdrawing unit and piperidine in a chloroform solution to carry out a Knoevenagel condensation reaction at a reaction temperature of 50-65° C. for a reaction time of 8-24 h to obtain a product represented by formula (1).

8. The method for preparing a triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen according to claim 7, characterized in that: The molar ratio of the bilateral bromide, the unilateral tin compound and tetrakis(triphenylphosphine)palladium is 1:2-2.5:0.05-0.2; The molar ratio of the D1-A2-D2 intermediate to phosphorus oxychloride is 1:2-2.5:0.05-0.2; The molar ratio of the CHO-D1-A2-D2-CHO intermediate to the A1 electron-withdrawing unit is 1:2-2.5:0.05-0.2; In step S1, the reaction temperature is 110-120°C and the reaction time is 6-12h; In step S2, the reaction temperature is 75-85°C and the reaction time is 12-18h; In step S3, the reaction temperature is 55-60° C. and the reaction time is 12-18 h.

9. A triplet photosensitizer molecule with near-infrared absorption and capable of efficiently generating singlet oxygen as claimed in claim 1, or a use of the triplet photosensitizer molecule made into nanoparticles as a singlet oxygen generating agent.

10. A triplet photosensitizer molecule having near-infrared absorption and capable of efficiently generating singlet oxygen as claimed in claim 1, or its use after being made into nanoparticles in photodynamic therapy.

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