High-stability optical functional iron complex and application thereof

Abstract

The invention discloses a high-stability optical functional iron complex, and particularly relates to a pyridine-imine iron (II) complex. The optical functional iron complex obtained by the invention has better stability in air and water, and can show obvious photocytotoxicity to human triple negative breast cancer cells by promoting the generation of active oxygen under the irradiation of red light, so that the optical functional iron complex can be used as a photosensitizer for photodynamic therapy, and has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the field of photofunctional complexes, and in particular relates to a photofunctional iron complex with high stability and application thereof. Background Art

[0002] In recent decades, photofunctional transition metal complexes have played a key role in various fields such as various light-induced chemical reactions, photoelectric conversion, organic light-emitting diodes and information encryption due to their unique structures and excellent photophysical and chemical properties. 6 or 8 Metal-based complexes composed of transition metals with different electronic configurations are the most popular. The excited state lifetime of these metal complexes can usually reach the microsecond level, and they can achieve highly efficient phosphorescence emission or diffusion process-controlled photochemical conversion. However, these classical transition metals are expensive and scarce, which has led to very limited development of their complexes. Therefore, it is particularly important to choose transition metals in the fourth period as replacements. As one of the most promising alternatives, iron not only has abundant reserves, but also has great advantages in environmental protection and low toxicity. In the past decade, iron-based complexes have made great progress. However, the publicly reported iron-based complexes still face the problems of relatively complex and polluting synthesis processes, unstable complexes, and easy deterioration / inactivation in the presence of air or water. Moreover, most of them can only absorb light in the ultraviolet-visible region (<600nm), lacking practical application prospects. Summary of the invention

[0003] The purpose of the present invention is to provide a highly stable photofunctional iron complex and its application as a photosensitizer.

[0004] To achieve the above object, the present invention adopts the following technical solution: A highly stable photofunctional iron complex, specifically a pyridine-imine iron (II) complex, with a molecular formula of [FeL 2 ] 2+ X, wherein L is selected from one of the following structural formulas: ; X=2Cl - or 2PF 6 - .

[0005] Specifically, the structural formula of the photofunctional iron complex is any one of the following: , Where X = 2Cl - or 2PF 6- .

[0006] The preparation method of the photofunctional iron complex comprises adding 8-aminoquinoline or its derivative and 2-pyridinecarboxaldehyde or its derivative into methanol and stirring and mixing, and then adding FeCl 2 or FeCl 2 With NaPF 6 The mixture was heated under reflux for 12 hours and then recrystallized to obtain the product.

[0007] Furthermore, the molar ratio of 8-aminoquinoline or its derivative to 2-pyridinecarboxaldehyde or its derivative is 1:1.

[0008] Furthermore, the FeCl 2 The molar ratio of pyridinecarboxaldehyde or its derivatives is 1:2.

[0009] Further, the mixture contains FeCl 2 With NaPF 6 The molar ratio is 1:2.

[0010] The photofunctional iron complex can be used as a photosensitizer for photodynamic therapy of tumors.

[0011] Furthermore, the tumor is specifically breast cancer.

[0012] The significant advantages of the present invention are: The present invention prepares a novel photofunctional iron complex through reasonable design and simple steps. The structure of the complex is easily adjustable, the properties are stable, and the complex has the characteristics of low toxicity and good biocompatibility. The absorption wavelength of the complex can reach the near-infrared region (effective absorption exceeds 650nm), and the complex can be used as an efficient red light responsive photosensitizer in biomedicine (photodynamic therapy). BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The schematic diagram of the reaction for preparing the photofunctional iron complex of the present invention is shown.

[0014] Figure 2 The product 1C prepared in Example 1 1 H-NMR spectrum.

[0015] Figure 3 This is the high-resolution mass spectrum of product 1C prepared in Example 1.

[0016] Figure 4 The product 2C prepared in Example 1 1 H-NMR spectrum.

[0017] Figure 5 This is the high-resolution mass spectrum of the product 2C prepared in Example 1.

[0018] Figure 6 The product 3C prepared in Example 1 1 H-NMR spectrum.

[0019] Figure 7 This is the high-resolution mass spectrum of the product 3C prepared in Example 1.

[0020] Figure 8 The product 1P prepared in Example 2 1 H-NMR spectrum.

[0021] Fig. 9 The product 1P prepared in Example 2 13 C-NMR spectrum.

[0022] Fig.10 This is the high-resolution mass spectrum of the product 1P prepared in Example 2.

[0023] Fig.11 The product 2P prepared in Example 2 1 H-NMR spectrum.

[0024] Fig.12 This is the high-resolution mass spectrum of the product 2P prepared in Example 2.

[0025] Fig.13 This is a perspective view of the single crystal structure of product 2P prepared in Example 2.

[0026] Fig.14 The product 3P prepared in Example 2 1 H-NMR spectrum.

[0027] Fig.15 The product 3P prepared in Example 2 13 C-NMR spectrum.

[0028] Fig.16 This is the high-resolution mass spectrum of the product 3P prepared in Example 2.

[0029] Fig.17 The product 4P prepared in Example 2 1 H-NMR spectrum.

[0030] Fig.18 The product 4P prepared in Example 2 13 C-NMR spectrum.

[0031] Fig.19 This is the high-resolution mass spectrum of the product 4P prepared in Example 2.

[0032] Fig. 20 UV-visible absorption spectra of complexes 1C-3C (a) and 1P-4P (b) in methanol.

[0033] Fig.21 The oxidation state of the complex 1C [Fe III (L1) 2 ] 3+ UV-Vis absorption spectrum in methanol.

[0034] Fig. 22 UV-visible absorption spectra of complexes 1C (a) and 1P (b) in different solutions.

[0035] Fig.23 UV-visible absorption spectra of complexes 1C (a, b) and 1P (c, d) in different aqueous solutions.

[0036] Fig.24 The results of MTT assay of complex 1C on human breast cancer cells (a) and fibroblast BJ cells (b).

[0037] Fig.25 Confocal microscopy images of human breast cancer cells before and after treatment with complex 1C under irradiation conditions.

[0038] Fig.26 This is the result of the generation of reactive oxygen species in living cells after human breast cancer cells were treated with complex 1C under irradiation conditions. DETAILED DESCRIPTION

[0039] A highly stable photofunctional iron complex is prepared by adding 8-aminoquinoline or a derivative thereof and 2-pyridinecarboxaldehyde or a derivative thereof to methanol in a molar ratio of 1:1 and stirring and mixing, and then adding FeCl 2 or FeCl in a molar ratio of 1:2 2 With NaPF 6 The mixture is heated under reflux for 12 hours and then recrystallized to obtain the photofunctional iron complex.

[0040] Among them, FeCl 2 The molar ratio of pyridinecarboxaldehyde or its derivatives is 1:2.

[0041] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0042] Example 1 [Fe(Ln) 2 ]Cl 2 Synthesis 2mmol of 8-aminoquinoline and its derivatives were dissolved in 45 mL of methanol to generate corresponding solutions. 2.1mmol of 2-pyridinecarboxaldehyde and its derivatives were dissolved in 5ml of methanol to generate corresponding solutions. Then the two solutions were mixed in pairs, stirred for 30 minutes, and then ferrous chloride (127mg, 1 mmol) was added to the mixture. After mixing, the mixture was heated to reflux overnight, then cooled to room temperature, and the solvent was removed by rotary evaporation. After the residue was dissolved in 5 mL of methanol, it was slowly diffused and recrystallized by adding ether (50 ml) dropwise to form a black precipitate. The precipitate was collected by filtration, washed with ether (3×30 mL), and the collected solid was dried in a vacuum to obtain the target product [Fe(Ln) 2 ]Cl 2 , marked as 1C-4C respectively.

[0043] Example 2 [Fe(Ln) 2 ](PF 6 ) 2 Synthesis 2 mmol of 8-aminoquinoline and its derivatives were dissolved in 45 mL of methanol to generate corresponding solutions. 2.1 mmol of 2-pyridinecarboxaldehyde and its derivatives were dissolved in 5 mL of methanol to generate corresponding solutions. The two solutions were then mixed in pairs, stirred for 30 minutes, and FeCl 2 (127 mg, 1 mmol) and NaPF 6 (366 mg, 2 mmol, mixed and heated to reflux overnight, then cooled to room temperature, the solvent was removed by rotary evaporation, the residue was dissolved in 5 mL of methanol, and then slowly diffused and recrystallized by adding ether (50 ml) dropwise to form a black precipitate. The precipitate was collected by filtration, washed with ether (3×30 mL), and the collected solid was dried in a vacuum to obtain the target product [Fe(Ln) 2 ](PF 6 ) 2 , marked as 1P-4P respectively.

[0044] The material was characterized by nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry, X-ray crystallography, etc., and the bond length and bond angle of the obtained 2P were determined using the obtained 2P as an example. The results are shown in Tables 1 and 2.

[0045] Table 1 Bond length data of 2P

[0046] Table 2 Bond angle data of 2P

[0047] The products 1C-3C and 1P-4P were measured by UV-Vis spectrophotometry in methanol (their concentration was 0.15 mM). The results showed that each product exhibited a very strong absorption band in the UV range (<400 nm), which may be attributed to the π / n-π* transition on the ligand. Interestingly, they also showed very obvious absorption peaks at about 660 nm (see Fig. 20 ).

[0048] The effects of oxidation state (ferrous and ferric ions) and solvent effects (in MeCN, MeOH, DMF, deionized water, and PBS buffer) on the UV-visible absorption spectra of products 1C and 1P were then studied. The results showed that there was no significant difference in the absorption characteristics of the products under different conditions (see Figure 21-22 ). At the same time, the absorbance signal changes of 1C and 1P in deionized water and PBS buffer solution for 7 days were also tested. The results showed that there was still an obvious absorption peak at about 660 nm (see Fig.23 These results indicate that this series of complexes have good stability.

[0049] Cytotoxicity test: Determination of cytotoxicity of the obtained photofunctional iron complex using 1C as an example 1. Human breast cancer cells MDA-MB-231 (ATCC HTB-26) and human fibroblast BJ cells (CRL-2522) were seeded at a density of 10,000 cells / well in a 96-well plate (TPP). After incubation overnight, different concentrations of complex 1C were added and cultured for 24 h. The cell viability was then determined by the MTT method, that is, the original culture medium was replaced with 100 μL of fresh culture medium containing 0.5 mg / mL MTT, and the cells were then cultured in an incubator at 37°C and 5% carbon dioxide for 4 hours. The culture medium was then replaced with 100 μL of DMSO, and the optical density (OD) of the plate was measured with 570 nm and 650 nm as references.

[0050] Depend on Fig.24 The results showed that, under the condition of no light, complex 1C had no obvious antiproliferative effect on these cells at a concentration of ≤100 μM, that is, no significant cytotoxicity.

[0051] 2. Human breast cancer MDA-MB-231 cells were added to DMEM medium supplemented with 10% fetal bovine serum and cultured in an incubator at 37°C and 5% carbon dioxide. 5The cells were seeded in the wells of the Lab-Tekii 8-well chamber at a density of 1 / well and cultured overnight. Hoechst 33342 and propidium iodide (PI) were then added for co-staining for 10 minutes, and then the stained cells were confocally imaged under 405 nm and 488 nm laser excitation conditions using a TCS SP8 multiphoton / confocal microscope to capture the fluorescence images of Hoechst 33342 and PI (as the cell viability "before treatment"). Then, the cells were treated with culture medium containing 100 μM complex 1C and without complex 1C, and the cells were irradiated with a 638 nm laser for 30 minutes, and the fluorescence images of Hoechst 33342 and PI were captured again (as the cell viability after "after treatment"). The results are shown in Fig.25 .

[0052] PI is a red fluorescent cell viability dye that is excluded from living cells because it does not permeate the cell membrane. However, PI can penetrate dead or damaged cells and emit an observable red fluorescent signal. Fig.25 It can be seen that the red signal of PI staining in cells treated with 100 μM complex 1C increased significantly after irradiation with 638 nm red light, indicating that treatment with 1C would induce cell damage or death.

[0053] To study its mechanism, we further tested the generation of reactive oxygen species (ROS) in living cells. Specifically, MDA-MB-231 cells were added to DMEM medium supplemented with 10% fetal bovine serum and cultured in an incubator at 37°C and 5% carbon dioxide. 5The cells were seeded in 96-well plates at a density of 1:1 / well and cultured overnight. Before the experiment, MDA-MB-231 was co-stained with Hoechst 33342 and MitoSOX in a 37°C incubator containing 5% carbon dioxide for 10 minutes. After staining, the stained cells were washed with complete medium, and the fluorescence signals of Hoechst 33342 and MitoSOX were detected under excitation wavelengths of 405 nm and 510 nm, respectively. Then, MDA-MB-231 cells were treated with 100 μM Fe complex 1C for 1 hour under red LED light (610-720 nm, 15 W). The cells were then completely washed with culture medium, and the fluorescence signals of Hoechst 33342 and MitoSOX in the treatment groups were measured again under excitation wavelengths of 405 nm and 510 nm. The changes in the fluorescence signals of MitoSOX relative to Hoechst 33342 before and after treatment were calculated to evaluate the level of ROS generation in MDA-MB-231 cells with or without 1C treatment under red light irradiation. The results showed that complex 1C could promote the generation of ROS in living MDA-MB-231 under red LED light irradiation (see Fig.26 ).

[0054] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A highly stable photofunctional iron complex, characterized in that: The photofunctional iron complex is specifically a pyridine-imine iron (II) complex, and its molecular formula is [FeL2] 2+ X, Wherein, L is selected from one of the following structural formulas: ； X=2Cl - or 2PF6 - .

2. A method for preparing the photofunctional iron complex according to claim 1, characterized in that: 8-aminoquinoline or its derivative and 2-pyridinecarboxaldehyde or its derivative are added to methanol and stirred and mixed, and then FeCl2 or a mixture of FeCl2 and NaPF6 is added, and heated under reflux for 12 hours, and then recrystallized to obtain the photofunctional iron complex.

3. The method for preparing the photofunctional iron complex according to claim 2, characterized in that: The molar ratio of the used 8-aminoquinoline or its derivative and the used 2-pyridinecarboxaldehyde or its derivative is 1:

1.

4. The method for preparing the photofunctional iron complex according to claim 2, characterized in that: The molar ratio of FeCl2 to 2-pyridinecarboxaldehyde or its derivatives is 1:

2.

5. The method for preparing the photofunctional iron complex according to claim 2, characterized in that: The molar ratio of FeCl2 to NaPF6 in the mixture is 1:

2.

6. Use of the photofunctional iron complex as claimed in claim 1 as a photosensitizer.

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