Mitochondrial targeting and apoptosis-inducing photosensitive iridium complex and preparation method thereof

Abstract

The invention discloses a mitochondrial targeting and apoptosis-inducing photosensitive iridium complex and a preparation method thereof, and particularly discloses a 2, 2 '-bipyridine compound, a cyclometalated iridium complex using the compound as a ligand, a preparation method and application of the 2, 2'-bipyridine compound as an antitumor drug. The cyclometalated iridium complex provided by the invention takes a 2, 2 '-bipyridine compound as a ligand, can selectively induce tumor cell apoptosis under an illumination condition, can be used for preparing antitumor drugs, and has a great potential value in the field of photodynamic treatment of tumors.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of mitochondrial targeting and inducing apoptosis photosensitive iridium complex and its preparation method, more particularly to a kind of 2,2'-dipyridyl compound, the cyclometalated iridium complex including the compound as ligand, preparation method and as antitumor drug application, belong to the chemical field. BACKGROUND

[0002] At present, malignant tumor is still one of the major diseases threatening human health worldwide, although there are various treatment methods including chemotherapy, radiotherapy, targeted therapy, etc., but there are still problems such as treatment resistance, poor targeting and strong systemic toxicity, which seriously limit its clinical efficacy. In recent years, photodynamic therapy has attracted widespread attention in the field of tumor treatment due to its non-invasiveness, spatial selectivity and controllability.

[0003] Mitochondria, as the core regulatory center of cell metabolism and apoptosis, exhibit high functional reprogramming characteristics in tumor cells, including redox imbalance, membrane potential change and metabolic pathway reconstruction, etc., which provides a unique therapeutic window. In recent years, more and more studies have shown that targeting mitochondria can effectively induce tumor cell death through mechanisms such as inducing reactive oxygen species (ROS) accumulation, disrupting mitochondrial membrane potential and activating apoptosis pathways. Based on this, developing anti-tumor molecules with mitochondrial targeting ability, especially drugs that can be activated and enhanced under specific conditions (such as light), has become an important research direction for new precise tumor treatment strategies.

[0004] Cyclometalated iridium (III) complexes have excellent photoactivity, and under light conditions, they can absorb light energy to jump to the excited state, then transfer energy to oxygen to generate highly cytotoxic singlet oxygen, causing local oxidative damage and selectively killing tumor cells. Therefore, developing a cyclometalated iridium (III) complex with good mitochondrial targeting ability that can selectively induce tumor cell apoptosis under light conditions is of great significance for improving the efficiency of photodynamic therapy and the precision of tumor treatment. SUMMARY

[0005] In view of the above problems existing in the prior art, the purpose of the present application is to provide a kind of 2,2'-dipyridyl compound, the cyclometalated iridium complex including the compound as ligand, preparation method and as antitumor drug application.

[0006] To achieve the above-mentioned purpose, the technical solutions adopted by the present application are as follows: The present application provides a kind of 2,2'-dipyridyl compound, the structure general formula is as shown in formula I: ; Wherein: n is any one natural number in 0-6; m is any one natural number from 0 to 3; X1, X2 are independently selected from any one of S, O, NH, CH2; R1, R2, R3, R4, R5, R6, R7 are independently selected from any one of hydrogen, halogen (e.g. fluorine, chlorine, bromine, iodine), nitro, cyano, C1-C6 alkyl (including straight chain alkyl, straight chain alkyl, cycloalkyl, e.g. methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, t-butyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, etc.), C2-C6 alkenyl (e.g. vinyl, propenyl, butenyl, etc.), C1-C6 alkoxy (e.g. methoxy, ethoxy, propoxy, etc.), C6-C20 aryl (e.g. phenyl, 1-naphthyl, 2-naphthyl, 9-anthryl, etc.), C5-C20 heterocyclic group (e.g. aziridinyl, oxetanyl, furanyl, thienyl, pyrrolyl, imidazolyl, thiazolyl, pyranyl, indolyl, etc.), OCOR a , COR b , COOR c , NR d R e ; R a , R b , R c , R d , R e are independently selected from any one of C1-C6 alkyl, C6-C20 aryl.

[0007] In one embodiment, n is any one natural number from 1 to 6; m is any one natural number from 2 to 3; X1, X2 are independently selected from any one of S, O, NH, CH2; R1, R2, R3, R4, R5, R6, R7 are independently selected from any one of hydrogen, halogen, nitro, cyano, C1-C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxy (e.g. methoxy, ethoxy, propoxy, etc.), phenyl, OCOR a , COR b , COOR c , NR d R e ; R a , R b , R c , R d , R e are independently selected from any one of C1-C6 alkyl, phenyl.

[0008] In one preferred embodiment, the 2,2'-bipyridine compound of Formula I has any one of the following structures: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 .

[0009] The present application also provides a method for preparing a 2,2'-bipyridine compound, which comprises reacting a compound I-1, a compound I-2, a condensing agent and a catalyst in a first solvent to obtain a 2,2'-bipyridine compound of Formula I, and the specific reaction formula is shown as follows: .

[0010] In one embodiment, the first solvent is dichloromethane or trichloromethane.

[0011] In one embodiment, the condensing agent is any one of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), dicyclohexyl carbodiimide (DCC), 2-(7-oxazolylbenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU), O-benzotriazole-tetramethyluronium hexafluorophosphate (HBTU), and preferably 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC).

[0012] One embodiment, the catalyst is 4-dimethylaminopyridine (DMAP) or triethylamine (Et3N), preferably 4-dimethylaminopyridine (DMAP).

[0013] One embodiment, the molar ratio of compound I-1: compound I-2: condensing agent: catalyst is (4.5-5.5):6:(0.5-1.5), preferably 5:6:6:1.

[0014] One embodiment, after the reaction, the second solvent is added to wash, the organic phase is extracted, dried and concentrated, and column chromatography is performed to obtain the 2,2'-bipyridine compound shown in formula I.

[0015] One preferred embodiment, the second solvent is water.

[0016] One preferred embodiment, compound I-1, compound I-2, EDC and DMAP in a molar ratio of 5:6:6:1 are reacted in dichloromethane for 15-30 hours (preferably 24 hours), after the reaction, the reaction solution is washed with water, the organic phase is concentrated, and column chromatography is performed to obtain the 2,2'-bipyridine compound shown in formula I.

[0017] The present application also provides a cyclometalated iridium complex [Ir(N-C)2L] + PF6 - , wherein the ligand is the 2,2'-bipyridine compound shown in formula I, and the structural general formula (omitting the anion part) is shown in formula II: ; the structural general formula of formula II is shown in formula III: ; wherein: R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 are each independently selected from hydrogen, halogen (e.g., fluorine, chlorine, bromine, iodine), nitro, cyano, hydroxyl, aldehyde, C1-C6 alkyl (including straight-chain alkyl, straight-chain alkyl, cyclic alkyl, e.g., methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, t-butyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, etc.), C2-C6 alkenyl (e.g., vinyl, propenyl, butenyl, etc.), C1-C6 alkoxy (e.g., methoxy, ethoxy, propoxy, etc.), C6-C20 aryl (e.g., phenyl, 1-naphthyl, 2-naphthyl, 9-anthryl, etc.), C5-C20 heterocyclic group (e.g., aziridinyl, oxetanyl, furanyl, thienyl, pyrrolyl, imidazolyl, thiazolyl, pyranyl, indolyl, etc.), OCOR f , COR g , COOR h ​, NR i R j R 10 , R 11 , R 12 , R 13 , R 14 form a saturated or unsaturated carbocyclic ring by covalent bond; R f , R g , R h , R i , R j are independently selected from any one of C1-C6 alkyl, C6-C20 aryl.

[0018] In one embodiment, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 are independently selected from any one of hydrogen, halogen (e.g., fluorine, chlorine, bromine, iodine), nitro, cyano, hydroxyl, aldehyde, C1-C6 alkyl (including straight chain alkyl, straight chain alkyl, cyclic alkyl, e.g., methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, t-butyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, etc.), C2-C6 alkenyl (e.g., vinyl, propenyl, butenyl, etc.), C1-C6 alkoxy (e.g., methoxy, ethoxy, propoxy, etc.), phenyl, OCOR f , COR g , COOR h , NR i R j ; or, adjacent R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 form a benzene ring by covalent bond; R f , R g , R h are independently selected from any one of C1-C6 alkyl; R i , R j are independently selected from any one of C1-C6 alkyl, phenyl.

[0019] In one preferred embodiment, formula III has any one of the following structures: , , , , , , , , 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 .

[0020] The present application also provides a preparation method of the cyclometalated iridium complex, which comprises refluxing an iridium precursor [Ir(N-C)2]Cl2 and the compound of formula I in a mixed solvent to obtain the cyclometalated iridium complex. .

[0021] In one embodiment, the mixed solution is a dichloromethane-methanol solution, and the volume ratio of dichloromethane to methanol is 1:1.

[0022] In one embodiment, the molar ratio of the iridium precursor to the compound of formula I is 1: (2.2-2.4).

[0023] In one embodiment, after the reaction, the solution is concentrated under reduced pressure, dissolved in methanol, and then ammonium hexafluorosulfate is added, and column chromatography is performed to obtain the cyclometalated iridium complex.

[0024] In one preferred embodiment, after the addition of ammonium hexafluorophosphate, the solution is allowed to react overnight at room temperature, concentrated, redissolved in dichloromethane, washed with water, concentrated, and then dropped into diethyl ether to precipitate and separate, and then filtered and dried to obtain the cyclometalated iridium complex.

[0025] In one preferred embodiment, the iridium precursor and the compound of formula I are refluxed in a 1:1 dichloromethane-methanol mixed solvent at a molar ratio of 1:2.2-2.4, and after the reaction, the solution is concentrated under reduced pressure, dissolved in a small amount of methanol, stirred after the addition of ammonium hexafluorophosphate, concentrated after the reaction, and recrystallized to obtain the cyclometalated iridium complex.

[0026] The present application also provides a use of the cyclometalated iridium complex in the preparation of an antitumor drug.

[0027] Compared with the prior art, the present application has the following remarkable advantages: The cyclic iridium complex provided by this invention, using the 2,2'-bipyridine compound shown in Formula I as a ligand, has good mitochondrial targeting and can selectively induce tumor cell apoptosis under light conditions. It is expected to be used to prepare anti-tumor drugs and has great potential value in the field of photodynamic therapy for tumors. Attached Figure Description

[0028] Figure 1 This is a diagram showing the mitochondrial targeting results of the cyclic iridium complex Ir1 prepared in this invention; Figure 2 This is a diagram showing the apoptosis induced by the cyclic iridium complex Ir1 prepared in this invention. Detailed Implementation

[0029] The technical solution of the present invention will be further described in detail and completely below with reference to the embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer.

[0030] Example 1: 2,2'-Bipyridine Compound Preparation of (ligand L1)

[0031] Will (0.21 g, 0.10 mmol) 0.2 g (0.10 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.23 g, 0.12 mmol), and 4-dimethylaminopyridine (0.012 g, 0.01 mmol) were stirred in dichloromethane for 24 hours. The reaction solution was washed with water, the organic phase was concentrated, and the solution was subjected to column chromatography to obtain a white solid, which was the target compound, abbreviated as ligand L1, with a yield of 82.5%.

[0032] Tested: 1HNMR (400 MHz, Chloroform-d) δ 8.67 (d, J = 5.0 Hz, 1H), 8.55 (d, J = 5.0 Hz, 1H), 8.38 (s, 1H), 8.25 (s, 1H), 7.29-7.26 (m, 1H), 7.16 (m, J = 5.1, 1.7 Hz, 1H), 5.21 (s, 2H), 3.60-3.51 (m, 1H), 3.21-3.05 (m, 2H), 2.48 (s, 1H), 2.47-2.42 (m, 5H), 1.89 (m, J = 13.7, 6.9 Hz, 1H), 1.78-1.63 (m, 4H), 1.49 (m, J = 18.3, 13.3, 9.2, 6.9 Hz, 2H); 13 CNMR (101 MHz, Chloroform-d) δ 173.06, 156.53, 155.43, 149.42, 148.93, 148.41, 146.09, 124.99, 122.14, 121.95, 119.53, 64.47, 56.30, 40.22, 38.52, 34.61, 33.96, 28.76, 24.68, 21.27; ESI-MS: m / z: 389.20 [M+H] + .

[0033] Example 2: Preparation of ligands L2-L10 According to the reaction conditions and post-processing of Example 1, the ligand L2-L10 in Example 1 were prepared by replacing the ligand L1 in Example 1 with respectively. , , , , , , , , , respectively, to obtain ligands L2-L10, specifically: Ligand L2: , yield 79.8%, ESI-MS: m / z: 405.20 [M+H] + ; Ligand L3: , yield 80.2%, ESI-MS: m / z: 419.18 [M+H] + ; Ligand L4: Yield 80.8%, ESI-MS: m / z: 433.20 [M+H] + ; Ligand L5: Yield 78.5%, ESI-MS: m / z: 147.20 [M+H] + ; Ligand L6: Yield 79.5%, ESI-MS: m / z: 451.21 [M+H] + ; Ligand L7: Yield 77.6%, ESI-MS: m / z: 418.22 [M+H] + ; Ligand L8: Yield 80.6%, ESI-MS: m / z: 409.14 [M+H] + ; Ligand L9: Yield 76.5%, ESI-MS: m / z: 400.18 [M+H] + ; Ligand L10: Yield 81.0%, ESI-MS: m / z: 401.20 [M+H] + .

[0034] Example 3: Cyclic Metal Iridium Complex Ir1 Preparation

[0035] Under nitrogen protection, [Ir(NC)2]Cl2 (specifically: [Ir(ppy)2Cl]2, 0.100 g, 0.093 mmol) and ligand L1 (0.073 g, 0.186 mmol) in a mixed solvent (V DCM :V MeOH The reaction mixture was refluxed in a 1:1 solution for 7 hours, the solution was evaporated to dryness, dissolved in a small amount of methanol, and then ammonium hexafluorophosphate (0.07 g, 0.38 mmol) was added and stirred for 5-7 hours. The reaction solution was concentrated and subjected to column chromatography to obtain a yellow solid, which is the cyclic iridium complex Ir1, with a yield of 76.4%.

[0036] Tested: 1HNMR (400 MHz, DMSO-d6) δ 8.82 (s, 1H), 8.75 (s, 1H), 8.26 (d, J = 8.2 Hz, 2H), 7.95 (s, 1H), 7.93 (d, J = 2.9 Hz, 2H), 7.91 (s, 2H), 7.83 (d, J = 5.7 Hz, 1H), 7.70 (d, J = 5.6 Hz, 1H), 7.65 (s, 1H), 7.63 (d, J = 7.1 Hz, 3H), 7.54 (d, J = 5.6 Hz, 1H), 7.16 (t, J = 6.6 Hz, 2H), 7.02 (t, J = 7.4 Hz, 2H), 6.90 (t, J = 7.4 Hz, 2H), 6.19 (t, J = 7.4 Hz, 2H), 5.32 (s, 2H), 3.63 - 3.53 (m, 1H), 3.34 (d, J = 1.7 Hz, 5H), 3.22 - 3.01 (m, 2H), 2.54 (s, 3H), 2.48 (s, 1H), 2.46 (s, 1H), 2.37 (m, J = 12.5, 6.3 Hz, 1H), 1.84 (m, J = 13.4, 6.8 Hz, 1H), 1.58 (m, J = 28.9, 13.6, 7.4 Hz, 5H), 1.37 (m, J = 8.6, 8.2 Hz, 2H); 13 CNMR (101 MHz, DMSO-d6) δ 173.00, 167.33, 167.27, 155.93, 155.17, 152.05, 151.00, 150.94, 150.28, 149.91, 149.57, 149.27, 144.29, 144.24, 139.22, 131.57, 131.51, 130.70, 129.89, 126.63, 126.20, 125.53, 124.37, 123.13, 122.70, 120.50, 63.62, 56.51, 38.55, 34.45, 33.50, 28.54, 24.48, 21.43; ESI-MS: m / z: 888.30 [M-H + ].

[0037] Example 4: Preparation of cyclometalated iridium complexes Ir2-Ir14 Referring to the reaction conditions and post-treatment of Example 3, the ligand L1 is kept unchanged, and the ligand L2 in Example 3 is replaced by , respectively, to obtain cyclometalated iridium complexes Ir2-Ir14 in turn, specifically: cyclometalated iridium complex Ir2: cyclometalated iridium complex Ir2: yield 73.2%, ESI-MS: m / z: 916.30 [M-H + ]; cyclometalated iridium complex Ir3: yield 73.5%, ESI-MS: m / z: 940.30 [M-H + ]; cyclometalated iridium complex Ir4: yield 72.5%, ESI-MS: m / z: 956.20 [M-H + ]; cyclometalated iridium complex Ir5: yield 70.2%, ESI-MS: m / z: 938.30 [M-H + ]; cyclometalated iridium complex Ir6: yield 70.1%, ESI-MS: m / z: 978.28 [M-H + ]; cyclometalated iridium complex Ir7: yield 73.5%, ESI-MS: m / z: 920.30 [M-H + ]; cyclometalated iridium complex Ir8: yield 70.5%, ESI-MS: m / z: 1040.35 [M-H + ]; cyclometalated iridium complex Ir9: yield 77.5%, ESI-MS: m / z: 948.30 [M-H + ]; cyclometalated iridium complex Ir10: ​​​​​​​​​​​​Yield 70.8%, ESI-MS: m / z: 944.28 [MH] + ]; Ir11, a metallic iridium complex: Yield 72.5%, ESI-MS: m / z: 972.30 [MH] + ]; Ir12, a metallic iridium complex: Yield 72.1%, ESI-MS: m / z: 1004.30 [MH] + ]; Ir13, a metallic iridium complex: Yield 73.6%, ESI-MS: m / z: 974.37 [MH] + ]; Ir14, a metallic iridium complex: Yield 71.8%, ESI-MS: m / z: 988.30 [MH] + ].

[0038] Example 5: Preparation of cyclic iridium complexes Ir15-Ir23 Following the reaction conditions and post-treatment of Example 3, [Ir(NC)2]Cl2 was maintained. Without changing the original composition, ligand L1 in Example 3 was replaced sequentially with ligands L2-L10 to obtain iridium complexes Ir15-Ir23, specifically as follows: Ir15, a metallic iridium complex: Yield 78.5%, ESI-MS: m / z: 904.30 [MH] + ]; Ir16, a metallic iridium complex: Yield 70.3%, ESI-MS: m / z: 919.27 [MH] + ]; Ir17, a metallic iridium complex: Yield 70.3%, ESI-MS: m / z: 932.29 [MH] + ]; Ir18, a metallic iridium complex: Yield 71.5%, ESI-MS: m / z: 916.30 [MH] + ]; Ir19, a metallic iridium complex: Yield 68.5%, ESI-MS: m / z: 950.30 [MH] + ]; Ir20, a metallic iridium complex: , yield 69.8%, ESI-MS: m / z: 917.30 [M-H + ]; Metal iridium complex Ir21: , yield 72.6%, ESI-MS: m / z: 908.25 [M-H + ]; Metal iridium complex Ir22: , yield 73.1%, ESI-MS: m / z: 899.28 [M-H + ]; Metal iridium complex Ir23: , yield 73.6%, ESI-MS: m / z: 900.30 [M-H + ]。

[0039] Example 6: Cytotoxicity experiment of cyclometalated iridium complexes Cytotoxicity experiments were performed on cyclometalated iridium complexes Ir1-Ir23 prepared in the examples to investigate their cytotoxicity in human ovarian cancer cells A2780, human cervical cancer cells Hela, human cervical squamous carcinoma cells Siha, human hepatocellular carcinoma cells HepG2, and human embryonic kidney cells 293T, respectively, so as to evaluate their anti-tumor activity. The specific CCK8 experiment steps are as follows: (1) The five cells (A2780, Hela, Siha, HepG2 and 293T) needed for recovery were cultured with fresh complete medium (DMEM medium + 10vol% fetal bovine serum + 1vol% penicillin-streptomycin), and after 3-4 passages, the experiment was started; (2) When the cells grow to the logarithmic growth phase, the cells are inoculated into a 96-well plate at 5000 cells / well, and cultured in a 37°C, 5% CO2 incubator; (3) After the cells adhere, add fresh medium containing different concentrations of iridium complexes or cisplatin (CDDP) to replace the original medium, mix gently, and the dark group is incubated in the dark for 48 hours; the light group is irradiated with 405 nm laser at a power of 15 mw / cm 2 for 3 minutes after 12 hours of incubation, and continues to incubate for 36 hours; (4) After 48 hours of incubation, the original culture medium is aspirated, fresh complete medium containing 10vol% CCK8 solution is added, mixed gently, and incubated in a 37°C incubator for 1-4 hours. The A450 nm is detected by an enzyme-labeled immunoassay instrument, the cell proliferation inhibition rate is calculated, and the IC 50 value (the IC 50 value is the drug concentration when the inhibition rate is equal to 50%, and the greater the IC 50 value, the lower the cytotoxicity); the experimental results are shown in Tables 1-5.

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] From Table 1-Table 5, the cyclometalated iridium complexes Ir1-Ir23 provided by the application exhibit different cell inhibition effects under dark and light conditions. The complexes exhibit moderate cell inhibition effect under dark condition, close to cisplatin (CDDP), and the cyclometalated iridium complexes Ir1-Ir23 exhibit stronger inhibition effect under light condition, better than cisplatin, which shows that the cyclometalated iridium complexes Ir1-Ir23 of the application have excellent photoactivity and have more excellent antitumor activity under light condition.

[0046] In Table 1-Table 5, 293T is normal kidney cell, IC 50 The greater the value, the lower the cytotoxicity. From the table, it can be seen that the IC 50 values of the cyclometalated iridium complexes Ir1-Ir23 on tumor cells are significantly lower than the IC 50 values on normal kidney cells 293T, which shows that the cytotoxicity of the iridium complexes Ir1-Ir23 on normal kidney cells 293T is weaker than that on four kinds of tumor cells, and the inhibition effect on normal kidney cells 293T is weaker than that on four kinds of tumor cells, which may be related to the uptake efficiency of normal cells. Compared with tumor cells, normal cells have lower metabolic efficiency and uptake efficiency, which means that they may take in less amount of iridium complexes into cells, resulting in higher IC 50 values.

[0047] Example 7: Mitochondrial targeting experiment of cyclometalated iridium complex The mitochondrial targeting experiment of the cyclometalated iridium complex Ir1 was carried out, and the specific steps were as follows: (1) A2780 cells in logarithmic growth phase were diluted to 3×10 4The cells were evenly spread in a 3 cm confocal culture dish, and after 24 hours of culture for cell adhesion, 10 μM complex Ir1 was added for 1 hour of incubation, the culture medium was removed, and PBS was washed once. Complete culture medium containing 150 nM commercial mitochondrial green fluorescent dye MitoTracker Deep Green (MTG, 150 nM) and commercial lysosome green fluorescent dye LysoTracker Deep Green (LTG, 150 nM) was added for 30 minutes of incubation, the culture medium was removed, fresh culture medium was added, and the confocal microscope was used for photography. The excitation wavelength of the complex was 405 nm, the excitation wavelength of MTG was 490 nm, and the excitation wavelength of LTG was 500 nm. The emission light receiver was 610±30 nm (complex Ir1), 515±15 nm (MTG), and 515±10 nm (LTG); (2) The organelle co-localization experiment was further confirmed. The experimental results are shown in Figure 1 It can be seen that.

[0048] As shown in Figure 1 , the overlap degree of the complex Ir1 and the commercial mitochondrial dye is very high, and the co-localization coefficient can reach 0.98. On the contrary, the overlap degree of the complex Ir1 and the commercial lysosome dye is relatively low, and the co-localization coefficient is only 0.36. This shows that the complex Ir1 has good mitochondrial targeting, and can selectively localize in the mitochondria of tumor cells after entering the cells.

[0049] Example 8: Inducing cell apoptosis experiment of cyclometalated iridium complex The cyclometalated iridium complex Ir1 was subjected to an inducing cell apoptosis experiment, and the specific steps were as follows: (1) A2780 cells were evenly spread in a 6-well plate at 5×10 4 cells / well, and after 24 hours of culture for cell adhesion, the original culture medium was removed, and fresh culture medium containing different concentrations of Ir1 (0.5 μM, 1 μM) was added. The dark group was incubated in the dark for 24 hours, and the light group was irradiated with a 405 nm laser at a power of 15 mw / cm 2 for 3 minutes after 12 hours of incubation, and then incubated for another 12 hours; (2) After 24 hours of incubation, the original culture medium was removed, and PBS was washed once. The cells were trypsinized and collected in an EP tube, washed once with PBS to remove residual trypsin, centrifuged, and after removing the supernatant, dye was added (first add 195 μL 1×Annexin V-FITC binding solution, then add 5 μL Annexin V-FITC dye, and finally add 10 μL PI dye), and then the machine was detected as soon as possible; (3) To determine the apoptosis-inducing effect of the complex Ir1 on A2780 cells, flow cytometry was used to analyze A2780 cells by Annexin V-FITC / PI double staining. The experimental results are as follows: Figure 2 As shown.

[0050] from Figure 2 As can be seen, under dark conditions, the number of apoptotic cells in the control group was 6.16% (the sum of early and late apoptotic cells). After induction with the complex Ir1, the number of apoptotic cells in A2780 cells was 6.51% (0.5 μM) and 16.54% (1 μM), respectively, representing increases of 0.35% and 10.38% compared to the control group. Under light conditions, the number of apoptotic cells in the control group was 6.20%. After induction with the complex Ir1, the number of apoptotic cells in A2780 cells was 15.10% (0.5 μM) and 35.49% (1 μM), respectively, representing increases of 8.90% and 29.29% compared to the control group. This indicates that the complex Ir1 has the ability to induce apoptosis in A2780 cells, and exhibits better results under light conditions.

[0051] Finally, it should be noted that the above are only some preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A 2,2'-bipyridine compound, characterized in that, Its general structural formula is shown in Formula I: ； Where: n is any natural number from 0 to 6; m is any natural number from 0 to 3; X1 and X2 are each independently selected from any one of S, O, NH, and CH2; R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen, halogen, nitro, cyano, C1-C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxy, C6-C20 aryl, C5-C20 heterocyclic, and OCOR. a COR b COOR c NR d R e Any one of them; R a R b R c R d R e Each is independently selected from any one of C1-C6 alkyl and C6-C20 aryl groups.

2. A method for preparing the 2,2'-bipyridine compound as described in claim 1, characterized in that, The reaction of compound I-1, compound I-2, a condensing agent, and a catalyst in a first solvent yields the 2,2'-bipyridine compound shown in Formula I, as detailed in the following reaction formula: 。 3. The method for preparing the 2,2'-bipyridine compound according to claim 2, characterized in that: The first solvent is dichloromethane or trichloromethane.

4. The method for preparing the 2,2'-bipyridine compound according to claim 2, characterized in that: The condensing agent is any one of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, dicyclohexylcarbodiimide, 2-(7-benzotriazole oxide)-N,N,N',N'-tetramethylurea hexafluorophosphate, and O-benzotriazole-tetramethylurea hexafluorophosphate.

5. The method for preparing the 2,2'-bipyridine compound according to claim 2, characterized in that: The catalyst is 4-dimethylaminopyridine or triethylamine.

6. The method for preparing the 2,2'-bipyridine compound according to claim 2, characterized in that: The molar ratio of compound I-1: compound I-2: condensing agent: catalyst is (4.5-5.5):6:(0.5-1.5).

7. A cyclic metallic iridium complex, characterized in that, It includes compounds of Formula I as claimed in claim 1 as ligands, the general structural formula of which is shown in Formula II: In Formula II The general structural formula is shown in Formula III: ;in: R8, R9, R 10 R 11 R 12 R 13 R 14 Each group is independently selected from hydrogen, halogen, nitro, cyano, hydroxyl, aldehyde, C1-C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxy, C6-C20 aryl, C5-C20 heterocyclic, OCOR f COR g COOR h NR i R j Any one of them; or, adjacent R8, R9, R 10 R 11 R 12 R 13 R 14 They form saturated or unsaturated carbon rings through covalent bonds; R f R g R h R i R j Each is independently selected from any one of C1-C6 alkyl and C6-C20 aryl groups.

8. The cyclic metallic iridium complex according to claim 7, characterized in that: R8, R9, R 10 R 11 R 12 R 13 R 14 Each group is independently selected from hydrogen, halogen, nitro, cyano, hydroxyl, aldehyde, C1-C6 alkyl, C2-C6 alkenyl, C1-C6 alkoxy, phenyl, and OCOR. f COR g COOR h NR i R j Any one of them; or, adjacent R8, R9, R 10 R 11 R 12 R 13 R 14 A benzene ring is formed between them through covalent bonds; R f R g R h Each alkyl group is independently selected from C1-C6 alkyl groups; R i R j Each is independently selected from any one of C1-C6 alkyl or phenyl groups.

9. A method for preparing the cyclic metallic iridium complex as described in claim 7, characterized in that, The iridium precursor [Ir(NC)2]Cl2 and the compound of formula I are refluxed in a mixed solvent to obtain a cyclic metallic iridium complex, as shown in the specific reaction formula below: 。 10. The use of the cyclic iridium complex as described in claim 7 in the preparation of antitumor drugs.

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