A type of near-infrared light-excited iridium (III) complex photosensitizer, preparation method and application

Abstract

The present invention discloses a class of near-infrared light-excited iridium (III) complex photosensitizers, a preparation method, and applications, belonging to the technical field of biomedical materials. The near-infrared light-excited iridium (III) complex photosensitizers of the present invention are characterized by combining cyclometallated C^N ligands with different conjugated structures with N^N ligands having a large conjugated structure of "electron donor-electron acceptor-electron donor (D-A-D)", so that the near-infrared light-excited iridium (III) complex photosensitizers have absorption in the near-infrared I region (700-1000 nm), and the emission peak is located in or extends to the near-infrared II region (>1000 nm). Under irradiation with 808 nm near-infrared light, under normoxic or hypoxic conditions, the photosensitizers can sensitize the surrounding matrix to produce reactive oxygen species such as singlet oxygen and superoxide anions, effectively killing 4T1 cancer cells and achieving photodynamic therapy with enhanced photothermal synergy.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and in particular relates to a near-infrared light-excited iridium (III) complex photosensitizer, a preparation method and an application thereof. Background Art

[0002] Cancer has always posed a serious threat to human life and health, but traditional methods of treating cancer in clinical practice have various defects. In recent years, photodynamic therapy (PDT) has attracted widespread attention as an emerging treatment method. Compared with traditional treatment methods, PDT has the advantages of being non-invasive, highly specific, minimally invasive, with low side effects and negligible drug resistance. It has shown great potential in tumor treatment and has been approved for the treatment of various tumor diseases. Photodynamic therapy excites photosensitizers through light of a specific wavelength. The activated photosensitizers react with the matrix in the cells (oxygen, water or protein, etc.) to produce cytotoxic reactive oxygen species, which in turn lead to cell apoptosis or necrosis. Based on the different photochemical reaction mechanisms, photodynamic therapy is generally divided into type I and type II mechanisms. The type I mechanism is that the photosensitizer in the triplet excited state undergoes an electron transfer reaction with oxygen or biological substrates (such as lipids or proteins) to generate free radicals or free radical ions, or continues to react with oxygen molecules to generate superoxide anions (O2· - ), hydrogen peroxide (H2O2), hydroxyl radicals (·OH), etc., thereby killing cancer cells. The type II mechanism is that the triplet excited state of the photosensitizer directly reacts with the ground state oxygen molecule to form highly toxic singlet oxygen ( 1O2), thereby killing cancer cells. Currently, the vast majority of photosensitizers are of this type. In comparison, type I photosensitizers, which are less dependent on oxygen and more effective against hypoxic tumors, are even rarer. Studies have shown that type I and type II processes usually occur simultaneously in PDT, and their ratio is closely related to multiple factors. Although the design principle of type I photosensitizers has not yet been established, it is clear that the efficient yield of triplet excited states is one of the important factors promoting their generation. Compared to most organic molecules, which are in the excited singlet state (S1) after photoexcitation, their S1→T1 intersystem crossing or T1→S0 radiative transitions are spin-forbidden. Transition metal complexes, especially metals such as ruthenium (III) and iridium (III), have heavy atom effects, resulting in stronger spin-orbit coupling, which can break the S1→T1 intersystem crossing barrier and thus have greater photosensitizer potential. However, most of the transition metal complex photosensitizers currently developed have short absorption and emission wavelengths (mostly in the ultraviolet-visible light region), resulting in insufficient tissue penetration depth, which greatly limits the application of this type of photosensitizer. It is particularly important to develop transition metal complex photosensitizers that can be excited by near-infrared light (light with a wavelength of 700-900nm can effectively penetrate tissue while avoiding absorption by tissue pigments and hemoglobin). On the other hand, photothermal therapy, which activates photothermal agents by near-infrared light to generate heat locally at the target site and then ablate tumors, has received widespread attention. Many studies have shown that photodynamic therapy with photothermal synergy has a more efficient killing rate for tumors. Therefore, for deep tumor tissues in an oxygen-deficient environment, it is of great significance to develop high-performance photosensitizers that are near-infrared excited and have both type I photodynamic / photothermal effects. However, the relevant transition metal complex photosensitizers are still very scarce, and the existing technology still needs further improvement and improvement. Summary of the Invention

[0003] To solve the above technical problems, the present invention proposes a class of near-infrared light-excited iridium (III) complex photosensitizers, preparation methods and applications. The near-infrared light-excited iridium (III) complex photosensitizer is a near-infrared light-excited iridium (III) complex photosensitizer with both type I photodynamic mechanism and photothermal conversion effect. It can be applied to the field of tumor photodynamic therapy and can solve the problems of the vast majority of existing transition metal complex photosensitizers having short excitation wavelengths (limited to the ultraviolet and visible light regions) and poor hypoxic tumor treatment effects.

[0004] To achieve the above objectives, the present invention provides the following technical solutions:

[0005] The present invention provides a type of near-infrared light-excited iridium (III) complex photosensitizer, the general structural formula of which is as follows:

[0006]

[0007] Wherein, the C^N ligand is any one of the following structures:

[0008]

[0009] X is any of the following two structures:

[0010]

[0011] R is an alkyl chain of varying lengths, any of the following structures:

[0012]

[0013] Preferably, the structural formula of the near-infrared light-excited iridium (III) complex photosensitizer is as follows:

[0014]

[0015] The present invention also provides a method for preparing the near-infrared light-excited iridium (III) complex photosensitizer, comprising the following steps: (1)

[0017] a) placing 4-bromotriphenylamine, 2-tributyltin-4-ylthiophene and tetrakistriphenylphosphine palladium in a reaction flask, sealing and deoxygenating, injecting the deoxygenated solvent, and reflux reaction under nitrogen protection. After the reaction, the intermediate product A is obtained by purification;

[0018] b) placing the intermediate product A in a reaction flask, sealing and deoxygenating, injecting an anhydrous solvent, adding n-butyl lithium dropwise at ultra-low temperature, stirring to react, adding tributyltin chloride dropwise after the reaction is completed, continuing the reaction, extracting after the reaction is completed, drying, and spinning the solvent to obtain an intermediate product B;

[0019] The synthetic routes for obtaining the intermediate product A and the intermediate product B are as follows:

[0020]

[0021] Wherein, R is an alkyl chain of different lengths, which can be any one of the following:

[0022]

[0023] or (2)

[0024] c) placing diphenylamine, 2-bromo-3-R-ylthiophene, sodium tert-butoxide, palladium acetate, and 2-dicyclohexylphosphino-2',6'-diisopropoxy-1,1'-biphenyl (Ruphos) in a reaction flask, sealing and deoxygenating, injecting the deoxygenated solvent, and refluxing under nitrogen protection. After completion of the reaction, the intermediate product C is obtained by purification;

[0025] d) placing the intermediate product C in a reaction flask, sealing and deoxygenating, injecting an anhydrous solvent, adding n-butyl lithium dropwise at ultra-low temperature, stirring to react, adding tributyltin chloride dropwise after the reaction is completed, continuing the reaction, extracting after the reaction is completed, drying, and removing the solvent under reduced pressure to obtain an intermediate product D;

[0026] The synthetic routes for obtaining the intermediate product C and the intermediate product D are as follows:

[0027]

[0028] Where R is an alkyl chain of varying lengths, any of the following structures:

[0029] (3)

[0031] e) adding 4,7-dibromo-5,6-dinitrobenzo[c][1,2,5]thiadiazole and tetrakistriphenylphosphine palladium to the intermediate product B or intermediate product D obtained above, placing the mixture in a reaction flask, sealing and deoxygenating the mixture, injecting the deoxygenated solvent, and refluxing the mixture under nitrogen protection. After the reaction is completed, the mixture is purified to obtain an intermediate product E;

[0032] f) placing the intermediate product E and zinc powder in a reaction flask, sealing and deoxygenating, injecting the deoxygenated solvent, and then adding an aqueous ammonium chloride solution thereto, and refluxing under nitrogen protection. After the reaction is completed, the intermediate product F is obtained by purification;

[0033] g) placing the intermediate product F and 1,10-phenanthroline-5,6-dione in a reaction flask, sealing and deoxygenating, injecting the deoxygenated solvent, and refluxing under nitrogen protection. After the reaction is completed, the intermediate product G is obtained by purification;

[0034] The synthetic routes for obtaining the intermediate product E, the intermediate product F and the intermediate product G are as follows:

[0035]

[0036] Where X is any of the following two structures:

[0037]

[0038] R is an alkyl chain of varying lengths, any of the following structures:

[0039]

[0040] (4) placing the C^N ligand and hydrated iridium trichloride in a reaction flask, sealing and deoxygenating, injecting the deoxygenated solvent, and reflux reaction under nitrogen protection. After the reaction is completed, water is added for precipitation, and filtration is performed to obtain a cyclometalated iridium dichloro bridge dimer [(C^N)2Ir(μ-Cl)2Ir(C^N)2];

[0041] The synthetic route for obtaining the cyclometallated iridium dichlorobridge dimer [(C^N)2Ir(μ-Cl)2Ir(C^N)2] is as follows:

[0042]

[0043] Wherein, the C^N ligand is any one of the following structures:

[0044]

[0045] (5) The intermediate product G and the cyclometallated iridium dichloro bridge dimer [(C^N)2Ir(μ-Cl)2Ir(C^N)2] are placed in a reaction bottle, sealed and deoxygenated, the deoxygenated solvent is injected, refluxed, cooled to room temperature, potassium hexafluorophosphate is added, and stirring is continued. After the reaction is completed, the near-infrared light-excited iridium (III) complex photosensitizer is obtained by purification. The synthesis route is as follows:

[0046]

[0047] Wherein, the C^N ligand is any one of the following structures:

[0048]

[0049] X is any of the following two structures:

[0050]

[0051] R is an alkyl chain of varying lengths, any of the following structures:

[0052]

[0053] Preferably, in a), the molar ratio of 4-bromotriphenylamine, 2-tributyltin-4-R-thiophene and tetrakistriphenylphosphine palladium is 1:1:0.02, the deoxygenated solvent is deoxygenated toluene, and after the deoxygenated toluene is injected, the reaction is preferably refluxed at 110° C. for 24 hours;

[0054] b), the molar ratio of the intermediate product A, n-butyl lithium and tributyltin chloride is 1:1.5:1.5, and the ultralow temperature is below -70°C, preferably -78°C (minus 78 degrees Celsius).

[0055] Preferably, in c), the molar ratio of diphenylamine, 2-bromo-3-R-ylthiophene, sodium tert-butoxide, palladium acetate and 2-dicyclohexylphosphino-2',6'-diisopropoxy-1,1'-biphenyl is 1.2:1:10:0.02:0.5, the deoxygenated solvent is deoxygenated toluene, and after the deoxygenated toluene is injected, the reaction is preferably refluxed at 110° C. for 24 hours;

[0056] In d), the molar ratio of the intermediate product C, n-butyl lithium and tributyltin chloride is 1:1.5:1.5, and the ultralow temperature is below -70°C, preferably -78°C.

[0057] Preferably, in e), the molar ratio of the intermediate product B or the intermediate product D to 4,7-dibromo-5,6-dinitrobenzo[c][1,2,5]thiadiazole and tetrakistriphenylphosphine palladium is 1:0.4:0.05, and the deoxygenated solvent is deoxygenated toluene. After the deoxygenated toluene is injected, the reaction is refluxed at 110°C for 24 hours.

[0058] Preferably, in f), the molar ratio of the intermediate product E, zinc powder and ammonium chloride is 1:120:36; the deoxygenated solvent is a deoxygenated mixed solvent of dichloromethane and methanol in an equal volume ratio, and the deoxygenated mixed solvent of dichloromethane and methanol is injected and refluxed at 30°C for 4 hours.

[0059] Preferably, in g), the molar ratio of the intermediate product F to 1,10-phenanthroline-5,6-dione is 1:1.2; the deoxygenated solvent is deoxygenated acetic acid, and after the deoxygenated acetic acid is injected, the reaction is refluxed at 80° C. for 12 hours.

[0060] The present invention also provides the use of the near-infrared light-excited iridium (III) complex photosensitizer in the preparation of a photosensitizer for tumor photodynamic therapy. The near-infrared light-excited iridium (III) complex photosensitizer has absorption in the near-infrared I region (700-1000nm), and the emission peak is located in or extends to the near-infrared II region (>1000nm).

[0061] The present invention also provides the use of the near-infrared light-excited iridium (III) complex photosensitizer in the preparation of near-infrared photodynamic therapy drugs. Under irradiation with 808nm near-infrared light, under normoxic or hypoxic conditions, the near-infrared light-excited iridium (III) complex photosensitizer can sensitize the surrounding matrix to produce reactive oxygen species.

[0062] The present invention also provides the use of the near-infrared light-excited iridium (III) complex photosensitizer in the preparation of drugs for treating deep-seated and hypoxic tumors.

[0063] The near-infrared light-excited iridium (III) complex photosensitizer of the present invention combines cyclometallated C^N ligands with different conjugated structures with N^N ligands with a large conjugated structure of "electron donor-electron acceptor-electron donor (DAD)" type, so that it has absorption in the near-infrared I region (700-1000 nm), and the emission peak is located in or extends to the near-infrared II region (>1000 nm). Under irradiation of 808 nm near-infrared light, under normoxic or hypoxic conditions, the near-infrared light-excited iridium (III) complex photosensitizer of the present invention can sensitize the surrounding matrix to produce active oxygen species such as singlet oxygen and superoxide anions. Under irradiation of 808 nm near-infrared light, the near-infrared light-excited iridium (III) complex photosensitizer of the present invention also has good photothermal stability and photothermal conversion performance. In summary, the near-infrared light-excited iridium (III) complex photosensitizer of the present invention can sensitize the surrounding matrix to produce reactive oxygen species such as singlet oxygen and superoxide anions under 808nm near-infrared light irradiation, both under normoxic or hypoxic conditions, and exhibits good photothermal conversion effect. It can achieve photodynamic therapy with photothermal synergistic enhancement for 4T1 cancer cells, showing great potential in the treatment of deep, hypoxic tumors.

[0064] Compared with the prior art, the present invention has the following advantages and technical effects:

[0065] The present invention provides a class of near-infrared light-excited iridium (III) complex photosensitizers, preparation methods, and applications. The near-infrared light-excited iridium (III) complex photosensitizers can be used in the field of photodynamic therapy. Compared with traditional photosensitizers, the present invention designs an N^N ligand with a DAD structure. Due to the intramolecular "push-pull" interaction and a large conjugated system, the absorption and emission wavelengths are significantly red-shifted. The introduction of a flexible alkyl chain gives it good solubility, facilitating material synthesis, separation and purification, and further structural modification. The iridium (III) complex photosensitizer prepared by the method of the present invention has no obvious cytotoxicity to mouse breast cancer 4T1 cells under no light conditions; however, under 808nm light conditions, both normoxic and hypoxic conditions, a large amount of reactive oxygen species are generated, showing obvious phototoxicity to 4T1 cells. At the same time, this type of iridium (III) complex photosensitizer has excellent photothermal conversion efficiency (greater than 20%) under continuous near-infrared light irradiation and exhibits good photothermal stability. The photosensitizer provided by the present invention not only exhibits an efficient type I photodynamic process, but also has excellent photothermal properties, realizing photodynamic therapy with synergistic photothermal enhancement, showing great potential in the field of deep, hypoxic tumor treatment and has very broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0067] Figure 1 The mass spectrum of the iridium (III) complex photosensitizer Ir-DTP provided in Example 1 of the present invention;

[0068] Figure 2 This is a hydrogen nuclear magnetic resonance spectrum of the iridium (III) complex photosensitizer Ir-DTP in deuterated chloroform provided in Example 1 of the present invention;

[0069] Figure 3 The mass spectrum of the iridium (III) complex photosensitizer Ir-ATP provided in Example 2 of the present invention;

[0070] Figure 4 The mass spectrum of the iridium (III) complex photosensitizer Ir-BTP provided in Example 3 of the present invention;

[0071] Figure 5 The mass spectrum of the iridium (III) complex photosensitizer Ir-CTP provided in Example 4 of the present invention;

[0072] Figure 6 This is the mass spectrum of the iridium (III) complex photosensitizer Ir-DTB provided in Example 5 of the present invention;

[0073] Figure 7 This is a hydrogen nuclear magnetic resonance spectrum of the iridium (III) complex photosensitizer Ir-DTB in deuterated chloroform provided in Example 5 of the present invention;

[0074] Figure 8 The absorption spectrum (a) and emission spectrum (b) of the iridium (III) complex photosensitizer Ir-DTP in aqueous solution provided in Example 1 of the present invention;

[0075] Figure 9 Absorption spectra of the iridium (III) complex photosensitizers Ir-ATP (a), Ir-BTP (b), and Ir-CTP (c) in aqueous solution provided in Examples 2, 3, and 4 of the present invention;

[0076] Figure 10 The absorption spectrum (a) and emission spectrum (b) of the iridium (III) complex photosensitizer Ir-DTB in aqueous solution provided in Example 5 of the present invention;

[0077] Figure 11This is a graph showing the relative emission intensity of the reactive oxygen indicator DCFH aqueous solution at 525 nm over time after 808 nm laser irradiation of the iridium (III) complex photosensitizer Ir-DTP provided in Example 1 of the present invention under normoxic conditions (a) and hypoxic conditions (b). In Figure a, DCFH N represents the curve measured under normoxic conditions with the addition of DCFH, DCFH+Ir-DTP N represents the curve measured under normoxic conditions with the addition of DCFH and the complex photosensitizer Ir-DTP, and DCFH+ICG N represents the curve measured under normoxic conditions with the addition of DCFH and ICG. The curves in Figure b are the corresponding curves measured under the same conditions as Figure a, except that normoxic conditions are replaced by hypoxic conditions, where N represents normoxic conditions and H represents hypoxic conditions.

[0078] Figure 12 The iridium (III) complex photosensitizer Ir-DTP provided in Example 1 of the present invention is irradiated with 808 nm laser under normal oxygen conditions (a) and hypoxic conditions (b) and the O2· - A graph showing the emission intensity of an aqueous solution of the indicator DHR123 at 525 nm versus time. In Figure a, DHR123 N represents the curve obtained under normoxic conditions with the addition of DHR123; DHR123+Ir-DTP N represents the curve obtained under normoxic conditions with the addition of DHR123 and the photosensitizer complex Ir-DTP; and DHR123+ICG N represents the curve obtained under normoxic conditions with the addition of DHR123 and ICG. The curves in Figure b are obtained under the same conditions as in Figure a, except that normoxic conditions are replaced with hypoxic conditions. N represents normoxic conditions, and H represents hypoxic conditions.

[0079] Figure 13 The iridium (III) complex photosensitizer Ir-DTP provided in Example 1 of the present invention was irradiated with 808 nm laser under normal oxygen conditions. 1 The relative absorbance of the O2 indicator ABDA aqueous solution at 375 nm changes over time, wherein ABDA represents the curve measured under normoxic conditions with the addition of ABDA, ABDA+ICG represents the curve measured under normoxic conditions with the addition of ABDA and ICG, and ABDA+Ir-DTP represents the curve measured under normoxic conditions with the addition of ABDA and the complex photosensitizer Ir-DTP;

[0080] Figure 14 (a) A graph showing the temperature change over time of aqueous solutions of the iridium (III) complex photosensitizer Ir-DTP provided in Example 1 of the present invention at different concentrations (0-100 μM) under 808 nm laser irradiation, and (b) a graph showing the temperature change over time of a 100 μM solution during five heating-cooling cycles.

[0081] Figure 15The toxicity test results of the iridium (III) complex photosensitizer Ir-DTP on 4T1 cancer cells under normoxic (a) and hypoxic (b) conditions in darkness and under 808 nm laser irradiation provided in Example 1 of the present invention are shown, wherein Ir-DTP Dark represents the result measured under dark conditions with the addition of the complex photosensitizer Ir-DTP, and Ir-DTP Laser represents the result measured under laser irradiation conditions with the addition of the complex photosensitizer Ir-DTP. DETAILED DESCRIPTION

[0082] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0083] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0084] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0085] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0086] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0087] Unless otherwise specified, room temperature in the present invention refers to 25±2°C.

[0088] All raw materials used in the examples of the present invention are commercially available.

[0089] The technical solution of the present invention is further illustrated by the following examples.

[0090] Example 1

[0091] Preparation of near-infrared light-excited iridium (III) complex photosensitizer Ir-DTP. The synthetic route is as follows:

[0092]

[0093] The specific synthesis steps are:

[0094] (1) Synthesis of compound 1: 4-bromotriphenylamine (6.17 mmol, 2.00 g), 2-tributyltin-4-hexylthiophene (6.17 mmol, 2.82 g) and tetrakistriphenylphosphine palladium (0.31 mmol, 358.22 mg) were placed in a reaction flask, sealed and deoxygenated, 20.00 mL of deoxygenated toluene was injected, and the reaction was refluxed at 110°C for 24 h. After cooling to room temperature, the solvent was evaporated under reduced pressure and purified by column chromatography to obtain yellow oily compound 11 (1.52 g, yield 76%). 1 H NMR (400MHz, DMSO-d6) δ (ppm): 7.52 (d, J = 8.6 Hz, 2H), 7.31 (t, J = 7.7 Hz, 4H), 7.25 (s, 1H), 7.08-7.01 (m, 7H), 6.96(d,J=8.7Hz,2H),2.55(t,J=7.5Hz,2H),1.58(t,J=7.4Hz,2H),1.28(q,J=3.8Hz,6H),0.87-0.83(m,3H).

[0095] (2) Synthesis of compound 2: Compound 1 (1.00 g, 2.43 mmol) was placed in a reaction flask, sealed and deoxygenated, 15.00 mL of anhydrous THF was injected, n-butyl lithium (2.70 mol / L, 3.60 mmol, 1.50 mL) was slowly added dropwise at -78°C, and the mixture was stirred for 2 h. After the reaction, tributyltin chloride (3.60 mmol, 0.98 mL) was slowly added dropwise, and the mixture was reacted at room temperature for 12 h. After the reaction, water was added for extraction, and the mixture was dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure without further purification to obtain dark yellow oily compound 2 (1.20 g, yield 70%).

[0096] (3) Synthesis of compound 3: Compound 2 (1.57 mmol, 1.00 g), 4,7-dibromo-5,6-dinitrobenzo[c][1,2,5]thiadiazole (0.63 mmol, 0.24 g) and tetrakistriphenylphosphine palladium (0.08 mmol, 90.71 mg) were placed in a reaction flask, sealed and deoxygenated, 15.00 mL of deoxygenated toluene was injected, and the reaction was refluxed at 110°C for 24 h. After cooling to room temperature, the solvent was evaporated under reduced pressure and purified by column chromatography to obtain a purple solid compound 3 (1.10 g, yield 65%). 1 H NMR (500MHz, DMSO-d6) δ7.59(d,J=8.4Hz,4H),7.49(s,2H),7.33(t,J=7.9Hz,8H),7.11-7.04(m,12H),6. 99(d,J=8.6Hz,4H),2.38(q,J=8.4Hz,4H),1.52(d,J=14.6Hz,4H),1.14-1.03(m,12H),0.77-0.69(m,6H).

[0097] (4) Synthesis of compound 4: Compound 3 (100.00 mg, 0.10 mmol) and zinc powder (746.46 mg, 11.48 mmol) were placed in a reaction flask, sealed and deoxygenated, and 10.00 mL of a mixed solvent of dichloromethane and methanol in an equal volume ratio after deoxygenation was injected. Then, a saturated aqueous solution of ammonium chloride (3.45 mmol, 184.29 mg) was added thereto. The mixture was refluxed at 30°C for 4 h. After cooling to room temperature, the solvent was evaporated under reduced pressure and purified by column chromatography to obtain an orange-yellow solid compound 4 (89.04 mg, yield 89%). 1 H NMR(400MHz,DMSO-d6)δ7.58(d,J=8.7Hz,4H),7.41(s,2H),7.33(t,J=6.9Hz,8H),7.09-6.99(m,1 6H),5.67(s,4H),2.41-2.26(m,4H),1.48(d,J=7.0Hz,4H),1.13-0.98(m,12H),0.73-0.65(m,6H).

[0098] (5) Synthesis of compound 5: Compound 4 (1.01 mmol, 1.00 g) and 1,10-phenanthroline-5,6-dione (1.21 mmol, 0.26 g) were placed in a reaction flask, sealed and deoxygenated, 15.00 mL of deoxygenated acetic acid was injected, and the mixture was refluxed at 80°C for 12 h. After cooling to room temperature, the pH was adjusted to neutral with sodium carbonate solution, extracted, separated, and the solvent was evaporated under reduced pressure. Purification was performed by column chromatography to obtain a green solid compound 5 (1.01 g, yield 93%). 1H NMR (500MHz, CDCl3) δ9.37(d,J=8.3Hz,2H),9.23(d,J=2.5Hz,2H),7.73(dd,J=8.0,4.6Hz,2H),7.65(d,J=8.6Hz,4H),7.30(t,J=15.8Hz,8.0Hz,8H), 7.16(dd,J=8.1Hz,14H),7.06(t,J=7.5Hz,4H),2.54(t,J=7.7Hz,4H),1.59 (d,J=15.5Hz,10H),1.25(s,2H),1.07-1.02(m,4H),0.59(t,J=6.7Hz,6H).

[0099] (6) Synthesis of compound [(Fppy)2Ir(μ-Cl)2Ir(Fppy)2]: 2-(2,4-Difluorophenyl)pyridine (3.14 mmol, 0.60 g) and iridium trichloride trihydrate (1.43 mmol, 0.56 g) were placed in a round-bottom flask. After deoxygenation, 15.00 mL of ethylene glycol ether was added to dissolve the reactants under nitrogen protection. 5.00 mL of water was then added, and the mixture was stirred and refluxed at 110°C for 24 h under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled to room temperature, water was added to settle, and the product was dried in vacuo to obtain a yellow solid (0.78 g, yield 89%).

[0100] (7) Synthesis of complex photosensitizer Ir-DTP: Compound 5 (0.10 mmol, 0.11 g) and [(Fppy)2Ir(μ-Cl)2Ir(Fppy)2] (0.04 mmol, 0.05 g) were placed in a reaction flask, sealed and deoxygenated, and a mixed solvent of deoxygenated dichloromethane and methanol (15.00 mL, volume ratio of 2:1) was injected. The reaction was carried out at 50°C for 12 h. After cooling to room temperature, potassium hexafluorophosphate (0.05 g) was added and the reaction was continued with stirring for 4 h. The solvent was dried by spin drying and purified by column chromatography to obtain a near-infrared light-excited iridium (III) complex photosensitizer Ir-DTP (0.12 g, yield 83%). 1H NMR (500MHz, CDCl3) δ9.55 (d, J=8.3Hz, 2H), 8.30 (dd, J=16.8, 7.9Hz, 4H), 7.94-7.89 (m,2H),7.77(t,J=7.8Hz,2H),7.63(d,J=8.4Hz,6H),7.29(d,J=7.8Hz,8H),7.13(dd, J=15.8,7.7Hz,15H),7.05(t,J=7.5Hz,7H),6.62(t,J=11.0Hz,2H),2.57(q,J=7.4Hz, 4H),1.27(d,J=16.2Hz,2H),1.10-0.95(m,14H),0.62(t,J=7.2Hz,6H).MALDI-TOF-MS m / z=1731.409.

[0101] The mass spectrum of the near-infrared light excited iridium (III) complex photosensitizer Ir-DTP obtained in this example and the nuclear magnetic resonance hydrogen spectrum in deuterated chloroform are shown as follows: Figure 1 and Figure 2 shown.

[0102] Example 2

[0103] Preparation of near-infrared light-excited iridium (III) complex photosensitizer Ir-ATP. The synthetic route is as follows:

[0104]

[0105] The specific synthesis steps are:

[0106] (1) Synthesis of compound [(Pql)2Ir(μ-Cl)2Ir(Pql)2]: 2-Phenylquinoline (1.46 mmol, 0.30 g) and iridium trichloride trihydrate (0.65 mmol, 0.23 g) were added to a two-necked flask, sealed and deoxygenated, and then, under nitrogen, 6.00 mL of ethylene glycol ethyl ether and 2.00 mL of water were added to dissolve the mixture. The mixture was stirred and refluxed at 110°C for 24 h. After the reaction was completed, the mixture was stopped, cooled to room temperature, and a large amount of water was added to allow the mixture to settle. The mixture was filtered under reduced pressure and dried in vacuo to obtain an orange solid [(Pql)2Ir(μ-Cl)2Ir(Pql)2] (0.21 g, yield 88%).

[0107] (2) Synthesis of complex photosensitizer Ir-ATP: Compound DTP (0.10 g, 0.09 mmol) and [(Pql)2Ir(μ-Cl)2Ir(Pql)2] (0.11 mg, 0.09 mmol) were added to a pre-dried two-necked flask, sealed and deoxygenated, and then, under nitrogen protection, a mixed solvent of deoxygenated dichloromethane and methanol (9.00 mL, volume ratio of 2:1) was injected. The mixture was reacted at 50°C for 12 h. After cooling to room temperature, potassium hexafluorophosphate (0.05 g) was added and the reaction was continued with stirring for 4 h. The solvent was then dried and purified by column chromatography to obtain the iridium (III) complex photosensitizer Ir-ATP (82.15 mg, yield 68%). MALDI-TOF-MS m / z = 1760.27.

[0108] The mass spectrum of the near-infrared light excited iridium (III) complex photosensitizer Ir-ATP obtained in this example is as follows Figure 3 shown.

[0109] Example 3

[0110] Preparation of near-infrared light-excited iridium (III) complex photosensitizer Ir-BTP. The synthetic route is as follows:

[0111]

[0112] The specific synthesis steps are:

[0113] (1) Synthesis of compound Bys: First, the solvent was deoxygenated. Toluene, potassium carbonate aqueous solution (2.20 mol / L), and ethanol were deoxygenated by bubbling nitrogen for 1 h. 2-Bromoisoquinoline (1.00 g, 5.18 mmol), benzothiophene-2-boronic acid (0.86 g, 4.81 mmol), and tetrakis(triphenylphosphine)palladium (0.14 g) were added to a dry volumetric flask, which was sealed and evacuated to remove oxygen. Toluene / ethanol / potassium carbonate aqueous solution (20 / 7 / 7 mL) was added under a nitrogen atmosphere, and the mixture was refluxed at 80°C for 24 h. After the reaction was completed, the mixture was cooled to room temperature, extracted, separated, and the product was purified by column chromatography to obtain a light yellow solid Bys (1.50 g, yield 93%).

[0114] (2) Synthesis of compound [(Bys)2Ir(μ-Cl)2Ir(Bys)2]: Compound Bys (0.99 mmol, 0.26 g) and iridium trichloride trihydrate (0.45 mmol, 0.15 g) were added to a two-necked flask, sealed and deoxygenated, and then, under nitrogen protection, 6.00 mL of ethylene glycol ethyl ether and 2.00 mL of water were added to dissolve the mixture. The mixture was stirred and refluxed at 110°C for 24 h. After the reaction was completed, the reaction was stopped, the mixture was cooled to room temperature, and a large amount of water was added to allow the mixture to settle. The mixture was filtered under reduced pressure and dried in vacuo to obtain an orange solid [(Bys)2Ir(μ-Cl)2Ir(Bys)2] (0.21 g, yield 88%).

[0115] (3) Synthesis of complex photosensitizer Ir-BTP: Compound DTP (0.10 g, 0.09 mmol) and [(Bys)2Ir(μ-Cl)2Ir(Bys)2] (0.11 g, 0.08 mmol) were added to a pre-dried two-necked flask, which was sealed and deoxygenated. Under nitrogen protection, deoxygenated dichloromethane (10.00 mL) and DMF (5.00 mL) were added. The mixture was reacted at 110°C for 12 h. After cooling to room temperature, potassium hexafluorophosphate (0.05 g) was added and the reaction was continued with stirring for 4 h. The solvent was evaporated and purified by column chromatography to obtain the iridium (III) complex photosensitizer Ir-BTP (95.12 mg, yield 63%). MALDI-TOF-MS m / z = 1872.43.

[0116] The mass spectrum of the near-infrared light excited iridium (III) complex photosensitizer Ir-BTP obtained in this example is as follows Figure 4 shown.

[0117] Example 4

[0118] Preparation of near-infrared light-excited iridium (III) complex photosensitizer Ir-CTP. The synthetic route is as follows:

[0119]

[0120] The specific synthesis steps are:

[0121] (1) First, the solvent was deoxygenated. Toluene, potassium carbonate aqueous solution (2.20 mol / L), and ethanol were deoxygenated by bubbling nitrogen for 1 h. Chlorophenanthrene (0.85 g, 4.00 mmol), benzothiophene-2-boric acid (0.85 g, 4.30 mmol), and tetrakis(triphenylphosphine)palladium (0.14 g, 0.12 mmol) were added to a pre-dried two-necked flask. After sealing and deoxygenation, a mixed solvent of toluene (20.00 mL), ethanol (7.00 mL), and potassium carbonate aqueous solution (7.00 mL) was added under nitrogen protection to dissolve the mixture. The mixture was refluxed at 80°C for 24 h. After the reaction, the mixture was cooled to room temperature, extracted, separated, and the product was purified by column chromatography to obtain a white solid Byp (0.81 g, yield 86%).

[0122] (2) Synthesis of compound [(Byp)2Ir(μ-Cl)2Ir(Byp)2]: Compound Byp (0.31 g, 0.99 mmol) and iridium trichloride trihydrate (0.15 g, 0.45 mmol) were placed in a round-bottom flask. After sealing and deoxygenation, 6.00 mL of ethylene glycol ethyl ether and 2.00 mL of water were added under nitrogen protection to dissolve the mixture. Stir and reflux the mixture at 110°C for 24 h. After the reaction was completed, the mixture was stopped and cooled to room temperature. A large amount of water was added to allow the mixture to settle. The mixture was filtered under reduced pressure and dried in vacuo to obtain a red solid [(Byp)2Ir(μ-Cl)2Ir(Byp)2] (0.28 g, yield 85%).

[0123] (3) Synthesis of complex photosensitizer Ir-CTP: Compound DTP (0.10 g, 0.09 mmol) and [(Byp)2Ir(μ-Cl)2Ir(Byp)2] (0.11 g, 0.07 mmol) were added to a pre-dried two-necked flask, which was sealed and deoxygenated. Under nitrogen protection, deoxygenated dichloromethane (10.00 mL) and DMF (5.00 mL) were added. The mixture was reacted at 110°C for 12 h. After cooling to room temperature, potassium hexafluorophosphate (0.05 g) was added and the reaction was continued with stirring for 4 h. The solvent was evaporated and purified by column chromatography to obtain the iridium (III) complex photosensitizer Ir-CTP (70.12 mg, yield 69%). MALDI-TOF-MS m / z = 1872.43.

[0124] The mass spectrum of the near-infrared light excited iridium (III) complex photosensitizer Ir-CTP obtained in this example is as follows Figure 5 shown.

[0125] Example 5

[0126] Preparation of near-infrared light-excited iridium (III) complex photosensitizer Ir-DTB, the synthetic route is as follows:

[0127]

[0128] The specific synthesis steps are:

[0129] (1) Synthesis of compound 6: Diphenylamine (0.82 g, 4.85 mmol), 2-bromo-3-hexylthiophene (1.00 g, 4.05 mmol), sodium tert-butoxide (3.80 g, 40.50 mmol), palladium acetate (0.09 g, 0.40 mmol) and 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl (RuPhos) (0.38 g, 0.81 mmol) were placed in a reaction flask, sealed and deoxygenated, and deoxygenated toluene was injected. The reaction was refluxed at 110°C for 24 h. After cooling to room temperature, the solvent was evaporated under reduced pressure and purified by column chromatography to obtain yellow oily compound 6 (1.13 g, yield 83%).

[0130] (2) Synthesis of compound 7: Compound 6 (1.00 g, 2.98 mmol) was placed in a reaction flask, sealed and deoxygenated, 10.00 mL of anhydrous THF was injected, n-butyl lithium (2.40 mol / L, 1.86 mL, 4.47 mmol) was slowly added dropwise at -78°C, and the mixture was stirred for 2 h. After the reaction, tributyltin chloride (1.82 mL, 6.71 mmol) was slowly added dropwise, and the mixture was reacted at room temperature for 12 h. After the reaction, water was added for extraction, and the mixture was dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure without further purification to obtain dark yellow oily compound 7 (1.30 g, yield 70%).

[0131] (3) Synthesis of compound 8: Compound 7 (1.86 g, 2.98 mmol), 4,7-dibromo-5,6-dinitrobenzo[c][1,2,5]thiadiazole (0.46 g, 1.19 mmol) and tetrakistriphenylphosphine palladium (0.15 mmol, 0.17 g) were placed in a reaction flask, sealed and deoxygenated, 15.00 mL of deoxygenated toluene was injected, and the reaction was refluxed at 110°C for 24 h. After cooling to room temperature, the solvent was evaporated under reduced pressure and purified by column chromatography to obtain a blue solid compound 8 (1.31 g, yield 63%).

[0132] (4) Synthesis of compound 9: Compound 8 (100.00 mg, 0.11 mmol) and zinc powder (896.91 mg, 13.71 mmol) were placed in a reaction flask, sealed and deoxygenated, and 10.00 mL of a mixed solvent of dichloromethane and methanol in equal volume ratio after deoxygenation was injected. Then, a saturated aqueous solution of ammonium chloride (220.05 mg, 4.11 mmol) was added thereto. The mixture was refluxed at 30°C for 4 h, cooled to room temperature, and the solvent was evaporated under reduced pressure. The mixture was purified by column chromatography to obtain an orange solid compound 9 (82.92 mg, yield 89%).

[0133] (5) Synthesis of compound 10: Compound 9 (200.00 mg, 0.25 mmol) and 1,10-phenanthroline-5,6-dione (61.89 mg, 0.29 mmol) were placed in a reaction flask, sealed and deoxygenated, 10.00 mL of deoxygenated acetic acid was injected, and the mixture was refluxed at 80°C for 12 h. After cooling to room temperature, the pH was adjusted to neutral with sodium carbonate solution, extracted, separated, and the solvent was evaporated under reduced pressure. Purification was performed by column chromatography to obtain a green solid compound 10 (222.44 mg, yield 90%).

[0134] (6) Synthesis of complex photosensitizer Ir-DTB: Compound 10 (150.00 mg, 0.15 mg) and [(Fppy)2Ir(μ-Cl)2Ir(Fppy)2] (77.66 mg, 0.07 mmol) were placed in a reaction flask, sealed and deoxygenated, and 15.00 mL of a mixed solvent of deoxygenated dichloromethane and methanol (volume ratio of 2:1) was injected. The reaction was carried out at 50°C for 12 h. After cooling to room temperature, potassium hexafluorophosphate (0.07 g) was added and the reaction was continued with stirring for 4 h. The solvent was dried by spin drying and purified by column chromatography to obtain a near-infrared light-excited iridium (III) complex photosensitizer Ir-DTB (175.74 mg, yield 83%). 1 H NMR (500MHz, CDCl3) δ8.30(d,J=10.3Hz,1H),7.80(t,J=8.1Hz,1H),7.71(d,J=6.2Hz,1H),7.34(t,J=8.0Hz,4H),7.25(d,J=9.2Hz,4H),7.14(dt ,J=24.6,6.9Hz,3H),6.62(t,J=9.3Hz,1H),5.76(dd,J=8.1,2.6Hz,1H), 1.62(t,J=7.1Hz,2H),1.32-1.12(m,14H),0.86(dt,J=11.9,6.7Hz,5H). MALDI-TOF-MS m / z=1580.914

[0135] The mass spectrum of the near-infrared light excited iridium (III) complex photosensitizer Ir-DTB obtained in this example and the nuclear magnetic resonance hydrogen spectrum in deuterated chloroform are shown as follows: Figure 6 and Figure 7 shown.

[0136] Test Example 1

[0137] The absorption and emission spectra of the near-infrared light-excited iridium (III) complex photosensitizer Ir-DTP prepared in Example 1 were tested:

[0138] Take 1980 μL of ultrapure water in a cuvette and add 20 μL of 10 -5Mix the N,N-dimethylformamide (DMF) solution of M photosensitizer Ir-DTP; take another 2mL of ultrapure water in another identical cuvette as a control, and use UV-visible absorption spectroscopy to measure its absorption spectrum in H2O and emission spectrum in H2O as shown in Figure 8 As shown in Figures a and b, the photosensitizer Ir-DTP has a maximum absorption wavelength of approximately 815 nm and an emission wavelength of approximately 1112 nm in H₂O. This indicates that the photosensitizer Ir-DTP exhibits near-infrared absorption and emission, which is beneficial for imaging and treatment of deep tissues.

[0139] Test Example 2

[0140] Absorption spectra of the iridium (III) complex photosensitizers Ir-ATP, Ir-BTP, and Ir-CTP prepared in Examples 2, 3, and 4 were tested:

[0141] Take 1980 μL of ultrapure water in a cuvette and add 20 μL of 10 -5 Mix the N,N-dimethylformamide (DMF) solution of M photosensitizer Ir-ATP; take another 2mL of ultrapure water in another identical cuvette as a control, and use UV-visible absorption spectroscopy to measure its absorption spectrum in H2O as shown below. Figure 9 The same method was used to test the absorption spectra of iridium (III) complex photosensitizers Ir-BTP and Ir-CTP, and the results were as follows: Figure 9 As shown in b and c.

[0142] Test Example 3

[0143] The absorption and emission spectra of the near-infrared light-excited iridium (III) complex photosensitizer Ir-DTB prepared in Example 5 were tested:

[0144] Take 1980 μL of ultrapure water in a cuvette and add 20 μL of 10 -5 Mix the N,N-dimethylformamide (DMF) solution of M photosensitizer Ir-DTB; take another 2mL of ultrapure water in another identical cuvette as a control, and use UV-visible absorption spectroscopy to measure its absorption spectrum in H2O and emission spectrum in H2O as shown in Figure 10 As shown in Figures a and b, the photosensitizer Ir-DTB has a maximum absorption wavelength of approximately 1110 nm and an emission wavelength of approximately 1234 nm in H₂O. This indicates that the complex, photosensitizer Ir-DTB, exhibits absorption and emission in the near-infrared II region, which is beneficial for imaging and treatment of deep tissues.

[0145] Test Example 4

[0146] The performance test of the active oxygen generation of the near-infrared light-excited iridium (III) complex photosensitizer Ir-DTP obtained in Example 1 under normoxic and hypoxic conditions:

[0147] The commercial fluorescent indicator 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) was used to detect the fluorescence at 808 nm (0.5 W·cm -2 ) Under laser irradiation, Ir-DTP produces total reactive oxygen species in aqueous solution. However, since DCFH-DA itself has no fluorescence, it needs to be metabolized by cells to generate 2',7'-dichlorodihydrofluorescein (DCFH) before it can react with reactive oxygen to produce green fluorescence. Therefore, detecting reactive oxygen in aqueous solution also requires converting DCFH-DA into DCFH. The specific conversion method is: first prepare a sodium hydroxide aqueous solution with a concentration of 0.01M, then prepare a DCFH-DA solution with a concentration of 1mM, and then mix the solutions in a ratio of sodium hydroxide solution / DCFH-DA solution (4 / 1, volume ratio). After mixing evenly, place the solution at room temperature for 30 minutes to wait for it to be fully hydrolyzed into DCFH. Then add PBS buffer solution 5 times the amount of sodium hydroxide aqueous solution to neutralize the pH to 7.4, and the final solution is stored in a -20°C refrigerator away from light. The concentration of the DCFH solution generated after hydrolysis is 40μM.

[0148] 20 μL Ir-DTP photosensitizer (1×10 -3 The DMF solution was added to 1980 μL DCFH solution and the solution was deoxygenated using an 808 nm (0.5 W cm -2 ) laser irradiation, with an interval of 30 seconds for a total of 5 minutes. A fluorescence spectrophotometer was used to measure the emission spectrum of DCFH in the range of 500-630 nm, with an excitation wavelength of 488 nm. The curve of emission intensity versus irradiation time was recorded. The mixed solution without photosensitizer was used as a blank group. The above steps were repeated. The same operation was performed using the same concentration of commercially available photosensitizer ICG. Correlation curves were obtained, and the trend of relative fluorescence intensity over time was calculated. Figure 11 As shown in a. Before the hypoxic test, the solution was deoxygenated and the other steps were repeated as in the normoxic environment. The relative fluorescence intensity change trend over time is shown in Figure 11 As shown in Figure b, compared with commercially available ICG, the emission intensity of the DCFH solution with the addition of photosensitizer Ir-DTP increased rapidly, indicating that the photosensitizer Ir-DTP has a strong reactive oxygen species generation property.

[0149] Test Example 5

[0150] The near-infrared light-excited iridium (III) complex photosensitizer Ir-DTP obtained in Example 1 was subjected to O2· - Generate performance test:

[0151] Dihydrorhodamine 123 (DHR123) was used as an indicator to detect O2· - The generation of non-fluorescent DHR123 and O2 - After the reaction, it will emit strong green fluorescence after being oxidized. The photosensitizer Ir-DTP and DHR123 with a molar ratio of 1:2 were added to a PBS / DMF (99 / 1, V / V) mixed solution to prepare a solution with a concentration of 10 μM. The emission spectrum of the solution was measured by a fluorescence spectrometer at 808 nm (0.5 W cm -2 ) laser irradiation, with an interval of 1 min and a total of 10 min. The fluorescence spectrum of DHR123 was tested immediately after each irradiation. The excitation wavelength was 495 nm, the range was 500-650 nm, and the fluorescence intensity at 525 nm was recorded to study the generation of O2· - The mixed solution without photosensitizer was used as blank group, and the above steps were repeated. At the same time, the same operation was performed with the commercial photosensitizer ICG at the same concentration to obtain the relevant change curve and calculate the change trend of its relative fluorescence intensity over time. Figure 12 As shown in a. It can be seen that the emission intensity of DHR123 solution with the addition of photosensitizer Ir-DTP increases rapidly, which indicates that the complex photosensitizer Ir-DTP has a strong O2· - Producing characteristics.

[0152] Before the hypoxia test, the solution was deoxygenated and the other steps were repeated as in the normoxic environment to obtain the relevant change curve and calculate the change trend of its relative fluorescence intensity over time. Figure 12 As shown in b. It can be seen that the emission intensity of DHR123 solution with the addition of the complex photosensitizer Ir-DTP increases rapidly, which indicates that the photosensitizer Ir-DTP can also produce considerable O2· - .

[0153] Test Example 6

[0154] The near-infrared light-excited iridium (III) complex photosensitizer Ir-DTP obtained in Example 1 was subjected to normal oxygen conditions. 1 O2 generation performance test:

[0155] Use ABDA to detect 1 The production of O2, ABDA and 1O2 reaction will generate endoperoxides, which will cause its absorbance at 378nm to decrease. ABDA is dissolved in DMF to prepare 2mL of 2mM ABDA mixed stock solution for use. Take a part of the mother liquor and dilute it with water to 2mL of 50μM mixed solution. The mixed solution without photosensitizer is used as the blank group. Take another 1mL of mother liquor, add 1.732mg of photosensitizer Ir-DTP, and dilute it with water to 10μM mixed solution. The mixed solution with photosensitizer Ir-DTP is used as the experimental group. Record the relevant absorbance change curve. Perform the same operation with the commercial photosensitizer ICG of the same concentration to obtain the relevant change curve, and calculate its relative absorbance change trend over time. Figure 13 As shown, the absorbance of the ABDA group alone barely decreased after laser irradiation, while the absorbance of the ICG group decreased. After 10 minutes of 808nm irradiation with Ir-DTP, the light absorption intensity of ABDA decreased significantly. This suggests that the photosensitizer Ir-DTP can generate high levels of singlet oxygen through a type II PDT mechanism.

[0156] Test Example 7

[0157] Photothermal effect test of the near-infrared light-excited iridium (III) complex photosensitizer Ir-DTP obtained in Example 1:

[0158] To measure the photothermal conversion efficiency, aqueous solutions of photosensitizer Ir-DTP with different concentrations (0 μM, 5 μM, 10 μM, 25 μM, 50 μM, and 100 μM) were exposed to 808 nm (1 W·cm -2 ) irradiation 10min, then the solution is cooled to room temperature. In this process, the temperature of the solution is recorded at intervals of 30s, and a curve is obtained as shown in FIG. Figure 14 As shown in a, the light-to-heat conversion efficiency (η) is calculated according to the formula reported in the literature. The formula is as follows:

[0159]

[0160] In formula (1), h represents the heat transfer coefficient (W / m·K), s represents the surface area of ​​the container (cm 2 ), T Max and T surr Represents the maximum steady-state temperature and ambient temperature (T Max -T surr =62.0-24.7=37.3, unit °C), Q dis is the heat dissipated from the laser mediated by the solvent and the container (J), I is the laser power (1.0 W cm -2 ), A represents the absorbance of the sample at 808 nm (A 808 =0.5674).

[0161]

[0162] In formula (2), m represents the mass of the solution containing the photoactive material (0.3 g), and C represents the specific heat capacity of the solution (Cwater = 4.2 J·g -1 ℃ -1 ), τ is the associated time constant.

[0163] Q dis =hs(T Max -T surr )(3)

[0164] t=-τlnθ(4)

[0165] In formula (4), θ is a dimensionless parameter called the driving force temperature.

[0166]

[0167] In formula (5), T Max : Maximum steady-state temperature (°C), T surr : Ambient temperature (℃).

[0168] Under continuous laser irradiation (808 nm, 1.0 W cm -2 ), the temperature of the Ir-DTP solution rises rapidly and reaches a steady state within 300s, while under the same conditions, the temperature change of pure water is negligible. The heating rate of Ir-DTP depends on the concentration of the material. A higher concentration may lead to a faster temperature rise. According to the method reported in the literature, the photothermal conversion efficiency (PCE) of Ir-DTP is calculated to be 20.26% using the photothermal curve and the related time constant. In addition, after five heating-cooling cycles, Ir-DTP is obtained. Figure 14 As shown in Figure b, no temperature decay was observed, indicating that the photosensitizer Ir-DTP has good photothermal stability and has the advantage of long-term phototherapy under near-infrared laser irradiation.

[0169] Test Example 8

[0170] Cytotoxicity test of the near-infrared light-excited iridium (III) complex photosensitizer Ir-DTP obtained in Example 1:

[0171] The cytotoxicity of photosensitizer Ir-DTP to 4T1 cancer cells was evaluated by CCK8 assay. 4T1 cancer cells were seeded in 96-well plates at a density of 1×10 cells per well. 4) and incubated in the above culture medium for 24 h. Then, aqueous solutions of photosensitizer Ir-DTP with different concentrations (0 μM, 10 μM, 20 μM, 40 μM, 50 μM, 60 μM, and 80 μM) were added and incubated for another 4 h. The cells were then illuminated with a laser (808 nm, 0.5 W·cm -2 ) irradiated for 5 minutes and incubated for another 20 hours. The culture medium was then removed, the cells were washed three times with PBS, and replaced with fresh culture medium (100 μL of fresh DMEM). The dark group was the same as the above steps under no light irradiation. 10 μL of freshly prepared CCK8 solution was added to each well, and after incubation in an incubator for 30 minutes, the absorbance value at 450 nm was read using a SpectraMax M5 microplate reader. Cell viability was determined by the ratio of the absorbance of 4T1 cancer cells incubated with Ir-DTP to the absorbance of PBS solution (control).

[0172] like Figure 15 As shown in Figure a, 4T1 cells treated with Ir-DTP showed a high survival rate in the dark under normoxic (21% O2) conditions. As the concentration of Ir-DTP NPs increased to 80 μM, the cell survival rate exceeded 97%. Ir-DTP did not show obvious cytotoxicity, indicating that it has good biocompatibility and sufficient safety. However, at 808 nm (0.5 W·cm -2 After 30 minutes of laser irradiation, the cell survival rate dropped sharply with the increase of concentration, which showed that Ir-DTP had obvious cell phototoxicity. Figure 15 As shown in b, it still exhibits excellent dark cytotoxicity and phototoxicity in a hypoxic (2% O 2 ) environment, indicating that it has a significant killing effect on 4T1 cancer cells under hypoxic conditions.

[0173] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A type of near-infrared light-excited iridium (III) complex photosensitizer, characterized in that: The general structural formula is as follows: ， Wherein, the C^N ligand is selected from the following structures: ； X is any of the following two structures: ； R is an alkyl chain of varying lengths, any of the following structures: 、 or .

2. The near-infrared light-excited iridium (III) complex photosensitizer according to claim 1, characterized in that: The structural formula is as follows: 、 、 or .

3. A method for preparing the near-infrared light-excited iridium (III) complex photosensitizer according to any one of claims 1 to 2, characterized in that: The steps include: （1） a) 4-bromotriphenylamine, 2-tributyltin-4-ylthiophene and tetrakistriphenylphosphine palladium are placed in a reaction flask, sealed and deoxygenated, and the deoxygenated solvent is injected. The reaction is refluxed under nitrogen protection. After the reaction is completed, the intermediate product A is obtained by purification; b) placing the intermediate product A in a reaction flask, sealing and deoxygenating the flask, injecting an anhydrous solvent, adding n-butyl lithium dropwise at ultra-low temperature, stirring and reacting, adding tributyltin chloride dropwise after the reaction, continuing the reaction, extracting after the reaction, drying, and spinning off the solvent to obtain the intermediate product B, wherein the ultra-low temperature is below -70°C; or (2) c) Diphenylamine, 2-bromo-3-ylthiophene, sodium tert-butoxide, palladium acetate, and 2-dicyclohexylphosphino-2',6'-diisopropoxy-1,1'-biphenyl are placed in a reaction flask, sealed and deoxygenated, and the deoxygenated solvent is injected. The reaction is refluxed under nitrogen protection, and the intermediate product C is obtained after purification after completion of the reaction; d) placing the intermediate product C in a reaction flask, sealing and deoxygenating the flask, injecting an anhydrous solvent, adding n-butyl lithium dropwise at ultra-low temperature, stirring to react, adding tributyltin chloride dropwise after the reaction, continuing the reaction, extracting after the reaction, drying, and removing the solvent under reduced pressure to obtain an intermediate product D, wherein the ultra-low temperature is below -70°C; （3） e) adding 4,7-dibromo-5,6-dinitrobenzo[c][1,2,5]thiadiazole and tetrakistriphenylphosphine palladium to the intermediate product B or intermediate product D obtained above, placing the mixture in a reaction flask, sealing and deoxygenating the mixture, injecting the deoxygenated solvent, and conducting a reflux reaction under nitrogen protection. After the reaction is completed, the mixture is purified to obtain an intermediate product E; f) placing the intermediate product E and zinc powder in a reaction flask, sealing and deoxygenating, injecting the deoxygenated solvent, and then adding an aqueous ammonium chloride solution thereto, and reflux reaction under nitrogen protection. After the reaction is completed, the intermediate product F is obtained by purification; g) placing the intermediate product F and 1,10-phenanthroline-5,6-dione in a reaction flask, sealing and deoxygenating, injecting the deoxygenated solvent, and reflux reaction under nitrogen protection. After the reaction, purify and obtain the intermediate product G; (4) Place the C^N ligand and hydrated iridium trichloride in a reaction flask, seal and deoxidize, inject the deoxidized solvent, and reflux under nitrogen protection. After the reaction is completed, add water for precipitation, and filter to obtain the cyclometalated iridium dichloro bridge dimer [(C ˄ N)2Ir(µ-Cl)2Ir(C ˄ N)2]; (5) The intermediate product G and the cyclometallated iridium dichloro bridge dimer [(C ˄ N)2Ir(µ-Cl)2Ir(C ˄ N)2] is placed in a reaction bottle, sealed and deoxygenated, the deoxygenated solvent is injected, reflux reaction is carried out, potassium hexafluorophosphate is added after cooling to room temperature, stirring is continued, and after the reaction is completed, the near-infrared light-excited iridium (III) complex photosensitizer is obtained through purification.

4. The method for preparing a near-infrared light-excited iridium (III) complex photosensitizer according to claim 3, characterized in that: a), the molar ratio of 4-bromotriphenylamine, 2-tributyltin-4-ylthiophene and tetrakistriphenylphosphine palladium is 1:1:0.02; b), the molar ratio of the intermediate product A, n-butyl lithium and tributyltin chloride is 1:1.5:1.

5.

5. The method for preparing the near-infrared light-excited iridium (III) complex photosensitizer according to claim 3, characterized in that: c), the molar ratio of diphenylamine, 2-bromo-3-R-ylthiophene, sodium tert-butoxide, palladium acetate and 2-dicyclohexylphosphino-2',6'-diisopropoxy-1,1'-biphenyl is 1.2:1:10:0.02:0.5; d), the molar ratio of the intermediate product C, n-butyl lithium and tributyltin chloride is 1:1.5:1.

5.

6. Use of the near-infrared light-excited iridium (III) complex photosensitizer according to claim 1 or 2 in the preparation of a photosensitizer for tumor photodynamic therapy, characterized in that: The near-infrared light-excited iridium (III) complex photosensitizer has absorption in the near-infrared I region, and the emission peak is located in or extends to the near-infrared II region.

7. Use of the near-infrared light-excited iridium (III) complex photosensitizer according to claim 1 or 2 in the preparation of near-infrared photodynamic therapy drugs, characterized in that: Under irradiation of 808 nm near-infrared light, under normoxic or hypoxic conditions, the near-infrared light-excited iridium (III) complex photosensitizer can sensitize the surrounding matrix to produce singlet oxygen or superoxide anions.

8. Use of the near-infrared light-excited iridium (III) complex photosensitizer according to claim 1 or 2 in the preparation of drugs for treating deep-seated, hypoxic tumors.

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