A metal iridium complex, its preparation method and application

Abstract

The present invention provides a metal iridium complex, a preparation method thereof and an application thereof, belonging to the technical field of compounds. The structural formula of the metal iridium complex is shown in Formula 1. The method is to first heat and reflux IrCl3·3H2O and (4-(2-pyridyl)benzaldehyde) to obtain (4-(2-pyridyl)benzaldehyde iridium dichloro bridge [Ir(pba)2Cl2]2; then place it and 4,7-dihydroxy-1,10-phenanthroline in the presence of a solvent in the dark and carry out a reflux reaction. After the reaction is completed, potassium hexafluorophosphate is added and stirring is continued to obtain the metal iridium complex CHO-Ir-H; finally, CHO-Ir-H and sodium hydroxide are mixed and stirred in water to obtain the metal iridium complex. The metal iridium complex of the present invention realizes dual-mode treatment by combining photodynamic therapy and ferroptosis.

Description

Technical Field

[0001] The present invention belongs to the technical field of compounds, and particularly relates to a metal iridium complex, a preparation method thereof, and an application thereof. Background Art

[0002] Photosensitizers in photodynamic therapy (PDT) can undergo a singlet-to-triplet transition under specific laser irradiation, and then convert the surrounding oxygen into cytotoxic reactive oxygen species (ROS), thereby achieving the purpose of treating diseases such as cancer. Compared with traditional cancer treatment methods (surgery, chemotherapy, radiotherapy), PDT has the advantages of less invasiveness, lower toxicity and side effects, and high specificity. The performance of photosensitizers plays a very important role in photodynamic therapy. Excellent PSs should have good water solubility, excellent 1 O2 generation ability, etc.

[0003] In recent years, a large number of cyclometalated iridium(III) complexes have attracted much attention due to their very superior anti-cancer activities, and are a class of new metal-based drugs that are promising to replace platinum drugs. Due to the characteristics of Ir(III) complexes such as high photochemical stability, long excited state lifetime, high luminescence efficiency, and tunable emission color, they have been widely studied as photosensitizers in applications such as photodynamic and photothermal cancer treatment. For example, the Chao Hui research group studied the anti-tumor activities of a series of cyclometalated iridium complexes substituted with different numbers of fluorine atoms. These complexes have better in vitro anti-cancer activities than cisplatin. Among various mechanisms affecting cancer treatment effects, the GSH-related antioxidant defense system is a major factor. As the main ROS scavenger in cells, GSH can directly neutralize excess ROS to maintain the redox homeostasis in cells and reduce the efficacy of PDT. GSH is a tripeptide composed of glycine, glutamic acid, and cysteine (Cys), and Cys is the main rate-limiting precursor for the synthesis of GSH. Therefore, the consumption of Cys can directly inhibit the biosynthesis of GSH, thereby increasing the accumulation of ROS in cancer cells. Summary of the Invention

[0004] The present invention provides a metal iridium complex, a preparation method thereof, and an application thereof. The metal iridium complex CHO-Ir-Na of the present invention simultaneously realizes the synergistic treatment effect of photodynamic therapy and ferroptosis by changing the cyclometalated ligand and using the cyclization reaction of the aldehyde group with Cys.

[0005] The present invention first provides a metal iridium complex, and its structural formula is shown in Formula 1:

[0006]

[0007] The present invention also provides a preparation method of a metal iridium complex, comprising the following steps:

[0008] Step 1: Under nitrogen protection, heat and reflux IrCl3·3H2O and 4-(2-pyridyl)benzaldehyde ligand to obtain iridium dichloro-bridged [Ir(pba)2Cl2]2 with 4-(2-pyridyl)benzaldehyde;

[0009] Step 2: Under nitrogen protection, place [Ir(pba)2Cl2]2 with 4-(2-pyridyl)benzaldehyde obtained in Step 1 and 4,7-dihydroxy-1,10-phenanthroline ligand in the presence of a solvent in the dark and carry out a reflux reaction. After the reaction is completed, add potassium hexafluorophosphate and continue stirring to obtain CHO-Ir-H;

[0010] Step 3: Mix and stir CHO-Ir-H obtained in Step 2 with NaOH in water to obtain the metal iridium complex CHO-Ir-Na.

[0011] Preferably, the reaction temperature in Step 1 is 120°C - 130°C, and the reaction time is 24 - 30 h.

[0012] Preferably, the molar ratio of IrCl3·3H2O and 4-(2-pyridyl)benzaldehyde ligand in Step 1 is 0.1:(0.2 - 0.3).

[0013] Preferably, the molar ratio of [Ir(pqy)2Cl2]2 with 4-(2-pyridyl)benzaldehyde and 4,7-dihydroxy-1,10-phenanthroline ligand in Step 2 is 1:2.

[0014] Preferably, the temperature of the reflux reaction in Step 2 is 75°C - 90°C, and the reaction time is 8 - 12 h.

[0015] Preferably, the molar ratio of CHO-Ir-H and NaOH in Step 3 is 1:2.

[0016] Preferably, the stirring temperature in Step 3 is room temperature, and the stirring time is 2 - 6 h.

[0017] The present invention also provides the application of the above metal iridium complex as a drug in the preparation of treating breast cancer.

[0018] Advantages of the present invention

[0019] The present invention provides a metal iridium complex, a preparation method thereof and an application. Through a simple and convenient method, the present invention designs and synthesizes a carrier-free water-soluble photosensitizer (PSs). Without the need for other amphiphilic polymers and nanocarrier materials, a water-soluble sodium salt photosensitizer with a high yield is obtained. Such photosensitizers avoid a series of side reactions and synthesis difficulties caused by adding additional carriers, and have better light absorption ability, thereby effectively improving its 1 O2 generation ability. In addition, due to the successful introduction of aldehyde groups into the cyclometalated ligands, CHO-Ir-Na can cause a decrease in the intracellular GSH content by consuming Cys in cancer cells, thereby inactivating glutathione peroxidase 4 (GPX4) and causing lipid peroxidation at the same time, ultimately achieving the therapeutic effect of ferroptosis-induced cell death. CHO-Ir-Na has good singlet oxygen generation ability and can achieve cell lipid peroxidation, realizing the dual-mode treatment of photodynamic therapy and ferroptosis of mouse breast cancer cells. Description of the Drawings

[0020] Figure 1 Schematic diagram for the preparation of CHO-Ir-Na prepared in Example 1 of the present invention;

[0021] Figure 2 Ultraviolet absorption spectrum of CHO-Ir-H prepared in Example 1 of the present invention in aqueous solution;

[0022] Figure 3 Fluorescence emission spectrum of CHO-Ir-H prepared in Example 1 of the present invention in aqueous solution;

[0023] Figure 4 Ultraviolet absorption spectrum of CHO-Ir-Na prepared in Example 1 of the present invention in aqueous solution;

[0024] Figure 5 Fluorescence emission spectrum of CHO-Ir-Na prepared in Example 1 of the present invention in aqueous solution;

[0025] Figure 6 Ultraviolet absorption spectrum of CHO-Ir-H prepared in Example 1 of the present invention under illumination and ICG conditions;

[0026] Figure 7 Ultraviolet absorption spectrum of CHO-Ir-Na prepared in Example 1 of the present invention under illumination and ICG conditions;

[0027] Figure 8 Time-dependent 1O2 generation kinetic curve diagram of CHO-Ir-H and CHO-Ir-Na prepared in Example 1 of the present invention;

[0028] Figure 9Cell survival rate graph of CHO-Ir-Na prepared in Example 1 of the present invention after being cultured in 4T1 cells for 24 hours;

[0029] Figure 10 Relative content graph of glutathione in 4T1 cells after being cultured with CHO-Ir-Na prepared in Example 1 of the present invention at different concentrations;

[0030] Figure 11 Graph of the production of intracellular lipid peroxides in 4T1 cells after being cultured with CHO-Ir-Na prepared in Example 1 of the present invention at different concentrations;

[0031] Figure 12 1H NMR spectrum of CHO-Ir-H prepared in Example 1 of the present invention 1 1H NMR spectrum of CHO-Ir-Na prepared in Example 1 of the present invention

[0032] Figure 13 1H NMR spectrum of CHO-Ir-Na prepared in Example 1 of the present invention 1 1H NMR spectrum of CHO-Ir-Na prepared in Example 1 of the present invention Detailed implementation manners

[0033] The present invention first provides a metal iridium complex with the molecular formula C 36 H 22 IrN4Na2O4, and the relative molecular mass is 813.11 g / mol. Its structural formula is shown in Formula 1:

[0034]

[0035] The present invention also provides a preparation method of the metal iridium complex, including the following steps:

[0036] Step 1: Under nitrogen protection, heat and reflux IrCl3·3H2O and 4-(2-pyridyl)benzaldehyde ligand to obtain 4-(2-pyridyl)benzaldehyde iridium dichloro bridge [Ir(pba)2Cl2]2;

[0037] Step 2: Under nitrogen protection, place 4-(2-pyridyl)benzaldehyde iridium dichloro bridge [Ir(pba)2Cl2]2 obtained in Step 1 and 4,7-dihydroxy-1,10-phenanthroline ligand in the presence of a solvent in the dark and carry out a reflux reaction. After the reaction is completed, add potassium hexafluorophosphate and continue to stir to obtain CHO-Ir-H;

[0038] Step 3: Mix and stir CHO-Ir-H obtained in Step 2 with NaOH in water to obtain the metal iridium complex CHO-Ir-Na.

[0039] The specific reaction process is as follows:

[0040]

[0041] According to the present invention, IrCl3·3H2O and 4-(2-pyridyl)benzaldehyde ligand are added to a reaction vessel containing a solvent and water, and the reaction is heated under reflux in an atmosphere protected by N2. The reaction temperature is preferably 120°C - 130°C, and the reaction time is preferably 24 - 30 h. After the reaction is cooled to room temperature, a large amount of poor solvent water is added thereto to precipitate a solid, which is then filtered, and washed multiple times with a large amount of solvents such as water and ethanol. The obtained solid is dried to obtain iridium dichloro-bridged [Ir(pba)2Cl2]2 with 4-(2-pyridyl)benzaldehyde. The solvent is preferably 2-ethylene glycol ethyl ether, and the molar ratio of IrCl3·3H2O to 1-phenylisoquinoline ligand is preferably 0.1:(0.2 - 0.3).

[0042] According to the present invention, iridium dichloro-bridged [Ir(pba)2Cl2]2 with 4-(2-pyridyl)benzaldehyde obtained above and 4,7-dihydroxy-1,10-phenanthroline ligand are added to a reaction vessel, and then a solvent is added. The solvent is preferably N,N-dimethylformamide. Under the condition of sufficiently filling with inert gas N2, the reaction is placed in the dark and refluxed. The reaction temperature is preferably 75°C - 90°C, and the reaction time is preferably 8 - 12 h. When the reaction is completed and cooled to room temperature, potassium hexafluorophosphate solid is added to the solution in the flask, and stirring is continued at room temperature. The stirring time is preferably 45 - 60 min. The solvent in the system is removed by a rotary evaporator, and then extracted with dichloromethane and water to remove the excess potassium hexafluorophosphate solid. The obtained substance is washed with petroleum ether and dried, and purified by column chromatography to obtain a red solid, which is CHO-Ir-H. The molar ratio of iridium dichloro-bridged [Ir(pba)2Cl2]2 with 4-(2-pyridyl)benzaldehyde to 4,7-dihydroxy-1,10-phenanthroline ligand is preferably 1:2.

[0043] According to the present invention, CHO-Ir-H and sodium hydroxide NaOH obtained above are added to a reaction vessel, and then solvent water is added, and stirring is carried out at room temperature. The stirring time is preferably 2 - 6 hours, and the product is dried at room temperature to obtain a red solid product, which is CHO-Ir-Na. The molar ratio of CHO-Ir-H to sodium hydroxide NaOH is preferably 1:2.

[0044] The present invention also provides the application of the above metal iridium complex CHO-Ir-Na as a drug in the dual-mode treatment of mouse breast cancer cells.

[0045] The present invention will be further described by way of the following examples, which do not limit the present invention in any way. Without departing from the technical solution of the present invention, any modification or change that is easily achievable by those of ordinary skill in the art will fall within the scope of the claims of the present invention.

[0046] Example 1

[0047] IrCl3·3H2O (0.1 mmol, 0.0352 g) and 4-(2-pyridyl)benzaldehyde ligand (0.3 mmol, 0.0549 g) were added to a round-bottom flask containing 30 mL of 2-ethoxyethanol and 10 mL of water. Under the protection of N2 atmosphere, the reaction was heated under reflux for 24 h. After the reaction was cooled to room temperature, a large amount of poor solvent water was added to precipitate the solid, which was then filtered and washed repeatedly with a large amount of solvents such as water and ethanol. The obtained solid was dried to obtain 4-(2-pyridyl)benzaldehyde iridium dichloro-bridged [Ir(pba)2Cl2]2 (1).

[0048] Cyclometalated iridium dichloro-bridged [Ir(pba)2Cl2]2 (0.1 mmol, 0.1184 g) 1 and 4,7-dihydroxy-1,10-phenanthroline ligand (0.2 mmol, 0.0424 g) were added to a 100 mL single-necked flask, and 50 mL of N,N-dimethylformamide was used as the solvent for the reaction system. Under the condition of fully filling with inert gas N2, the reaction was placed in the dark and refluxed for 8 h. When the reaction was cooled to room temperature after completion, 10 equivalents of potassium hexafluorophosphate solid was added to the solution in the flask, and the mixture was stirred at room temperature for 45 min. The solvent in the system was removed using a rotary evaporator, and dichloromethane and water were used for extraction to remove the excess potassium hexafluorophosphate solid. The obtained substance was washed with petroleum ether and dried, and purified by column chromatography to obtain a red solid, which was CHO-Ir-H (2).

[0049] CHO-Ir-H (2) (0.1 mmol, 0.0769 g) and NaOH (0.2 mmol, 0.008 g) were added to a 100 mL beaker, and water was used as the reaction solvent. The mixture was stirred at room temperature for 4 h. After the reaction was completed, evaporation was carried out at room temperature to obtain a red solid powder with a yield of 90%. The molecular formula was C 36 H 22 IrN4Na2O4, and the relative molecular mass was 813.11 g / mol. The 1H NMR spectra of the metal iridium complexes CHO-Ir-H and CHO-Ir-Na prepared in Example 1 are as shown in Figure 12 , 13.

[0050] Example 2

[0051] The preparation process and conditions are the same as those in Example 1, except that the reaction time in Step 1 is 28 h.

[0052] Example 3

[0053] The preparation process and conditions are the same as those in Example 1, except that the reaction time in Step 2 is 10 h.

[0054] Example 4

[0055] The preparation process and conditions are the same as those in Example 1, except that the reaction temperature in Step 1 is 125 °C.

[0056] Example 5

[0057] The preparation process and conditions are the same as those in Example 1, except that the reaction temperature in Step 2 is 90 °C.

[0058] Example 6

[0059] The preparation process and conditions are the same as those in Example 1, except that the reaction time in Step 2 is 10 h and the reaction temperature is 90 °C.

[0060] The metal iridium complex prepared in Example 1 was characterized for its performance as follows:

[0061] 1. Preparation of the metal iridium complex:

[0062] In the present invention, CHO-Ir-Na is prepared into a water-soluble sodium salt according to the Figure 1 schematic method in a simple and convenient manner. The specific operation is as follows: Add CHO-Ir-H(2) (0.1 mmol, 0.0769 g) and NaOH (0.2 mmol, 0.008 g) to a 100 mL beaker, use water as the reaction solvent, stir at room temperature for 4 hours. After the reaction is completed, evaporate at room temperature to obtain a red solid powder CHO-Ir-Na.

[0063] 2. Photophysical properties of the metal iridium complex

[0064] The photophysical properties of CHO-Ir-H and CHO-Ir-Na in the present invention were measured in aqueous solution. Figures 2 - 5 The ultraviolet absorption spectra and fluorescence emission diagrams of CHO-Ir-H and CHO-Ir-Na of the present invention are shown. As can be seen from the figures, CHO-Ir-H and CHO-Ir-Na show bright red light emission in aqueous solution, and the emission peak position is 600 nm. The ultraviolet absorption spectrum shows two typical absorption bands of metal iridium complexes. The strong ultraviolet absorption band is mainly attributed to the ligand spin-allowed π-π* transition, while the relatively weak absorption band originates from the metal-to-ligand charge transfer (3MLCT). Figure 2and Figure 4 it can be seen that after being prepared into the sodium salt, its absorption intensity is significantly improved, Figure 3 and Figure 5 it can be seen that its emission peak position basically remains unchanged.

[0065] 3. Singlet oxygen generation ability of the iridium metal complex:

[0066] Figure 6 This is the in vitro singlet oxygen generation experiment of CHO-Ir-H of the present invention. Under light illumination, when ICG and PSs coexist, the characteristic absorption peak of ICG at 790 nm will continuously decrease, which also proves that PSs can effectively generate 1O2 under light illumination. Its ability to generate 1O2 conforms to the first-order kinetic equation;

[0067] Figure 7 This is the in vitro singlet oxygen generation experiment of CHO-Ir-Na prepared by the present invention under light illumination and ICG conditions;

[0068] Figure 8 It is the kinetic curve graph of the time-dependent generation of 1O2 of CHO-Ir-H and CHO-Ir-Na; Figure 8 It shows that the equation slopes are sorted in the following order: slope of CHO-Ir-Na (0.00341) > CHO-Ir-H (0.000818137). The slope of CHO-Ir-Na is 4.2 times that of CHO-Ir-H. The larger the slope value, the stronger the 1O2 generation ability of the substance. It is proved that after forming the sodium salt, its ultraviolet absorption ability can be well improved. The stronger the light absorption ability, the more conducive to the generation of 1O2, so it can be suitable as an efficient PSs for PDT.

[0069] 4. Cell therapy experiment of CHO-Ir-Na:

[0070] Figure 9 This is the cell survival rate graph of CHO-Ir-Na of the present invention after being cultured in mouse breast cancer (4T1) cells for 24 h without light illumination and under light illumination; The 3-(4,5-dimethylthiazol-2)-2,5-diphenyltetrazolium bromide (MTT) experiment of CHO-Ir-Na of the present invention is used to study the potential toxicity of CHO-Ir-Na to 4T1 cells. The experimental process for detecting the cytotoxicity of photosensitizers by the MTT method is that 4T1 cells are seeded in a 96-well plate at a density of 10,000 cells per well. The cells are cultured in an incubator at 37 °C and 5% CO2 for 24 hours. After aspirating the old culture medium, PSs with different concentration gradients (0–10 μg mL-1 ) of RPMI Medium 1640 (100 μL) was added to each well. After 6 hours, the original medium was replaced with fresh RPMI Medium 1640 (100 μL). The light group was irradiated with 450 nm LED at 20 mW cm -2 for 30 minutes, while the dark group was not irradiated. After irradiation, the cells were placed in an incubator for 24 hours. MTT (10 μL) with a concentration of 5 mg mL -1 was added to each well. The cells were placed in an incubator for 4 hours. After 4 hours, DMSO (200 μL) was added to each well to replace the original medium. The absorbance value of the sample at 490 nm was detected by a microplate reader. It can be seen from Figure 9 that even when the concentration of the drug CHO-Ir-Na reached a relatively high concentration of 100 μM, under dark conditions, after culturing in cells for 24 hours, the survival rate of CHO-Ir-Na-incubated cells reached 90%, while under light conditions, the mortality rate of CHO-Ir-Na-incubated cells was very high, indicating its good phototoxicity and low dark toxicity.

[0071] Figure 10 This is about the change of the intracellular GSH level after culturing mouse breast cancer (4T1) cells with CHO-Ir-Na of the present invention. With the increase of the concentration of CHO-Ir-Na, the relative intracellular GSH level gradually decreased from 100% to about 79%, showing a dose-dependent decrease in GSH. The experimental results further illustrate that introducing an aldehyde group on the cyclometalated ligand of the metal iridium complex not only enhances its ultraviolet absorption ability but also can fully utilize the aldehyde group to further consume Cys, and shows a dose-dependent consumption of intracellular GSH in cell experiments. Figure 11 This is about the production of intracellular LPO under the incubation of different drug concentrations (0 μM, 50 μM, 100 μM) of CHO-Ir-Na of the present invention. It can be seen that with the increase of the drug concentration of CHO-Ir-Na, the green fluorescence of the Liperfluo probe gradually increases, showing a concentration-dependent production of LPO. It indicates that CHO-Ir-Na can cause lipid peroxidation by consuming cysteine and then consuming GSH, successfully inducing ferroptosis. The tests of the intracellular glutathione content and the test of LPO together show that CHO-Ir-Na can cause ferroptosis in cells, achieving the synergistic treatment of photodynamic therapy and ferroptosis, and is an excellent photosensitizer candidate applicable to photodynamic therapy.

Claims

1. A metal iridium complex, characterized in that, Its structural formula is shown in Formula 1:

2. A method for preparing the metal iridium complex according to claim 1, characterized in that, It includes the following steps: Step 1: Under nitrogen protection, heat and reflux IrCl3·3H2O and 4-(2-pyridyl)benzaldehyde ligand to obtain 4-(2-pyridyl)benzaldehyde iridium dichloro bridge [Ir(pba)2Cl]2; Step 2: Under nitrogen protection, place 4-(2-pyridyl)benzaldehyde iridium dichloro bridge [Ir(pba)2Cl]2 obtained in Step 1 and 4,7-dihydroxy-1,10-phenanthroline ligand in the presence of a solvent in the dark and carry out a reflux reaction. After the reaction is completed, add potassium hexafluorophosphate and continue stirring to obtain CHO-Ir-H; Step 3: Mix and stir CHO-Ir-H obtained in Step 2 with NaOH in water to obtain a metal iridium complex.

3. A method for preparing the metal iridium complex according to claim 2, characterized in that, The reaction temperature in Step 1 is 120°C - 130°C, and the reaction time is 24 - 30 h.

4. A method for preparing the metal iridium complex according to claim 2, characterized in that, The molar ratio of IrCl3·3H2O and 4-(2-pyridyl)benzaldehyde ligand in Step 1 is 0.1:(0.2 - 0.3).

5. A method for preparing the metal iridium complex according to claim 2, characterized in that, The molar ratio of 4-(2-pyridyl)benzaldehyde iridium dichloro bridge [Ir(pqy)2Cl]2 and 4,7-dihydroxy-1,10-phenanthroline ligand in Step 2 is 1:

2.

6. A method for preparing the metal iridium complex according to claim 2, characterized in that, The temperature of the reflux reaction in Step 2 is 75°C - 90°C, and the reaction time is 8 - 12 h.

7. A method for preparing the metal iridium complex according to claim 2, characterized in that, The molar ratio of CHO-Ir-H and NaOH in Step 3 is 1:

2.

8. A method for preparing the metal iridium complex according to claim 2, characterized in that, The stirring temperature in Step 3 is room temperature, and the stirring time is 2 - 6 h.

9. Use of the metal iridium complex according to claim 1 in the preparation of a medicament for treating breast cancer.

Images