A metal carbonyl Mn complex with 2-pyridinecarboxylic acid derivative as ligand, and a preparation method and application thereof

Abstract

The application belongs to the technical field of complex synthesis and application, and provides a metal carbonyl Mn complex with 2-pyridine carboxylic acid derivatives as ligands, a preparation method and application thereof; the complex has a chemical formula of [Mn(CO)3(L)Br], L is 2-pyridine carboxylic acid, 5-Cl-2-pyridine carboxylic acid, 5-Br-2-pyridine carboxylic acid or 6-Br-2-pyridine carboxylic acid methyl ester; the four kinds of complex with different substituent groups have high water solubility, and have obvious effects on improving the water solubility of CORM. The four kinds of complex can realize adjustable release of CO under different light wavelengths, and can be applied to the preparation of CO controlled release donors under visible light or near infrared light. The complex can be combined with human serum proteins to prepare serum protein complexes and be applied to complex metabolism regulation and cell targeting transportation. The complex can obviously inhibit the growth of human cervical cancer cells HeLa cells, and can be applied to the screening and preparation of antitumor drug lead compounds.

Description

Technical Field

[0001] The present invention belongs to the technical field of complex synthesis and application, and specifically relates to a metal carbonyl Mn complex with a 2-picolinic acid derivative as a ligand, its preparation method, and application. More specifically, it relates to a novel metal carbonyl Mn complex with Mn(CO)5Br as a reactant and a 2-picolinic acid derivative as a ligand, its preparation method, and application. The prepared metal carbonyl Mn complex has four different structures, and the application of this metal carbonyl Mn complex in the screening and preparation of drugs for anti-tumor lead compounds. The prepared metal carbonyl Mn complex can achieve release under different wavelengths of light, which is of great significance for regulating CO release. At the same time, this complex can recognize and bind to human serum albumin to form a new complex. In addition, the novel manganese metal carbonyl Mn complex with a 2-picolinic acid derivative as a ligand can be used in the screening and preparation of drugs for anti-tumor lead compounds. Background Art

[0002] Studies have shown that carbon monoxide (CO), similar to nitric oxide (NO), is an important gas messenger molecule in organisms and can play an important regulatory role in organisms, such as antibacterial, anti-inflammatory, antioxidant, platelet aggregation inhibition, vasodilation, etc. [1-2]. At present, the carbon monoxide releasers (CORMs) reported in research mainly include: 1. Organic compound-type CO prodrugs; 2. Borane carbonates and their derivatives; 3. Transition metal carbonyl compounds. The study of transition metal carbonyl complexes as CORMs has attracted much attention in the field of biometallic organic chemistry. The main ways for CORM to release CO include ligand substitution, pH triggering, enzyme triggering, and light induction [3-6]. Among them, photo-triggered CORM (PhotoCORM), that is, light-induced CO release, has unique advantages. Different light sources of different intensities and wavelengths can be used to irradiate CORM to achieve controlled release of CO without introducing additional reactants [7-8]. Most of the reported CORMs rely on short-wavelength, high-energy blue-violet light for catalytic release of CO [9]. However, this type of light is difficult to penetrate the skin and may be harmful to organisms. Therefore, it is necessary to develop long-wavelength visible light or near-infrared light to induce CO release. Manganese carbonyl compounds have good photosensitivity, so suitable ligands can be selected to improve the photochemical properties of such compounds.

[0003] Studies have shown that 2-picolinic acid (2-PA) can act as a metal chelator and coordinate with a variety of metal ions. 2-picolinic acid has a series of derivatives. By selecting ligands with appropriate substituent groups, the spatial structure of the complex can be adjusted, thereby improving the water solubility, stability and biological activity of the complex, providing a basis for the discovery of new biomacromolecule inhibitors and anti-tumor drugs [10-13]. At the same time, 2-picolinic acid derivatives can exhibit good biological activity in macrophages, activate macrophages, induce macrophages to resist cancer cells, and achieve the purpose of anti-tumor. Studies have shown that picolinic acid and its derivatives have a certain effect on inhibiting cancer cells, which is manifested in the ability to change the cell cycle of rat kidney cells (NRK) and block cell growth

[13] . Picolinic acid has been tested in various rodent experimental tumor systems and has shown certain experimental effects. Picolinic acid can promote the absorption of zinc in the intestine and Fe 3+ and Zn 2+

[14] Picolinic acid also showed a certain efficacy in inhibiting the growth of Escherichia coli and the spore formation of Bacillus subtilis

[15] .

[0004] In addition, 2-picolinic acid is an important organic synthesis intermediate and an important raw material for the preparation of carbocaine drugs. It plays an important role in medicine. It is also the synthetic raw material of many picolinates. For example, chromium picolinate is one of the effective ingredients in health foods

[16] . 2-picolinic acid ligands have different functional coordination atoms N and O, which can coordinate with different metals such as Fe, Mn, Cr, etc. to form molecules with various structures. These molecules can bind to human serum albumin, improving the selectivity and bioavailability of the complex in the body, and have certain application value

[17] . Serum albumin is the most abundant protein in human blood. It is a carrier of many endogenous and exogenous bioactive small molecules, including some drug molecules. The binding of the complex to serum albumin may change its pharmacokinetic process, thereby reducing its toxic side effects and improving the therapeutic effect [18-20].

[0005] References:

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[0011] [6] Jiang X, Xiao Z, Zhong W, et al. Brief survey of diiron andmonoiron carbonyl complexes and their potentials as CO-releasing molecules(CORMs). Coord Chem Rev. 2021; 429: 213634.

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[0013] [8] Ford P C. Metal complex strategies for photo-uncaging the small molecule bioregulators nitric oxide and carbon monoxide. Coord Chem Rev. 2018; 376: 548-564.

[0014] [9] Ustun E, Ozgur A, Coskun K A. Anticancer activities of manganese-based photoactivatable CO-releasing complexes (PhotoCORMs) with benzimidazole derivative ligands. Transit Metal Chem. 2017; 42(4):331-337.

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[10] Mjos KD, Orvig C. Metallodrugs in medicinal inorganic chemistry. Chem Rev. 2014; 114(8): 4540-63.

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[12] Rathgeb A, Böhm A, Novak MS, Gavriluta A, Dömötör O, Tommasino JB, Enyedy EA, Shova S, Meier S, Jakupec MA, Luneau D, Arion VB. Ruthenium-nitrosyl complexes with glycine, L-alanine, L-valine, L-proline, D-proline, L-serine, L-threonine, and L-tyrosine: synthesis, X-ray diffraction structures, spectroscopic and electrochemical properties, and antiproliferative activity. Inorg Chem. 2014; 53(5): 2718-29.

[0018]

[13] Salvini A, Frediani P, Rivalta E. Ruthenium carbonylcarboxylates with nitrogen containing ligands: Part V. On the syntheses and catalytic activity of new ruthenium complexes containing bicarboxylate ligands. Inorg Chim Acta. 2003; 351: 225-234.

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[14] Melillo G, Bosco MC, Musso T, Varesio L. Immunobiology of picolinic acid. Adv Exp Med Biol. 1996; 398:135-41.

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[15] Xicheng Liu, Junfei Liang, Jing You, Lei Ying, Yin Xiao, Shirong Wang, Xianggao Li, Small molecular hole-transporting and emitting materials for hole-only green organic light-emitting devices. Dyes and Pigments. 2016; 131 : 41-48.

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[16] Östman E, Samigullin A, Heyman-Lindén L, Andersson K, Björck I, Öste R, Humpert PM. A novel nutritional supplement containing amino acids and chromium decreases postprandial glucose response in a randomized, double-blind, placebo-controlled study. PLoS One. 2020; 15(6): e0234237.

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[17] Bijelic A, Theiner S, Keppler BK, Rompel A. X-ray Structure Analysis of Indazolium trans-[Tetrachlorobis(1H-indazole)ruthenate(III)](KP1019) Bound to Human Serum Albumin Reveals Two Ruthenium Binding Sites and Provides Insights into the Drug Binding Mechanism. J Med Chem. 2016; 59(12):5894-903.

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[18] Leboffe L, di Masi A, Polticelli F, Trezza V, Ascenzi P. Structural Basis of Drug Recognition by Human Serum Albumin. Curr Med Chem. 2020; 27(30): 4907-4931.

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[20] Liu X, Mohanty RP, Maier EY, Peng X, Wulfe S, Looney AP, Aung KL, Ghosh D. Controlled loading of albumin-drug conjugates ex vivo for enhanced drug delivery and antitumor efficacy. J Control Release. 2020; 328:1-12. SUMMARY

[0026] The present application aims to provide a metal carbonyl Mn complex with 2-picolinic acid derivatives as ligands, and its preparation method and application, and more specifically, to provide a novel metal carbonyl Mn complex with Mn(CO)5Br as a reactant and 2-picolinic acid derivatives as ligands, and its preparation method and application. The metal carbonyl complex is a complex with 2-picolinic acid derivatives as ligands and Mn as the central element. The complex forms a six-coordinated octahedral structure. Through synthesis and fine separation, four metal carbonyl manganese complexes with different substituent groups are prepared. The reactivity of each complex shows certain differences.

[0027] The application also provides the metal carbonyl manganese complex as a CO donor, and controllable adjustment of the release rate of the signal molecule under different light wavelengths. The application provides the possibility of the metal carbonyl manganese complex in improving the water solubility of CORM. The application provides that the metal carbonyl manganese complex is combined with human serum albumin, and the selectivity and bioavailability of the complex in the body are improved, and the metal carbonyl manganese complex has certain application value. The application also provides the application of the metal carbonyl manganese complex in anti-tumor compound drug screening.

[0028] The application is realized by the following technical solutions: a metal carbonyl Mn complex with 2-pyridine carboxylic acid derivatives as ligands, the chemical formula of the metal carbonyl Mn complex is [Mn(CO)3(L)Br], wherein L is 2-pyridine carboxylic acid, 5-Cl-2-pyridine carboxylic acid, 5-Br-2-pyridine carboxylic acid or 6-Br-2-pyridine carboxylic acid methyl ester, and the stereostructure of the metal carbonyl Mn complex is as follows:

[0029]

[0030] The application also provides a method for preparing the metal carbonyl Mn complex with 2-pyridine carboxylic acid derivatives as ligands, and the method comprises the following steps: taking Mn(CO)5Br as a reactant, taking 2-pyridine carboxylic acid derivatives as ligands, and preparing the carbonyl complex with different ligands and hexa-coordinated and octahedral structures through a synthesis reaction and fine separation; wherein the 2-pyridine carboxylic acid derivatives are 2-pyridine carboxylic acid, 5-Cl-2-pyridine carboxylic acid, 5-Br-2-pyridine carboxylic acid or 6-Br-2-pyridine carboxylic acid methyl ester.

[0031] Further, the specific steps are as follows:

[0032] (1) Synthesis of the metal carbonyl Mn complex [Mn(CO)3(L)Br]: 2 mmol of Mn(CO)5Br reactants and an equimolar amount of 2-pyridine carboxylic acid derivative ligands are respectively dissolved in 50 mL of a solvent system of methanol: n-hexane with a volume ratio of 4:1, the two are mixed, fully stirred, heated to reflux at 65 ℃ for 2 h; after the reaction is completed, the solvent is removed by distillation under reduced pressure, and then the sample is placed in a vacuum drying dish and dried under vacuum to obtain the crude product of the metal carbonyl Mn complex with mixed ligand coordination;

[0033] (2) The crude product of the metal carbonyl Mn complex coordinated by the mixed ligand obtained in step (1) is dissolved in dichloromethane and then separated by silica gel column chromatography; wherein: complex 1 is eluted from a mixed solution of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) in a volume ratio of 50:1; complex 2 is eluted from a mixed solution of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) in a volume ratio of 100:1; complex 3 is directly eluted from pure dichloromethane (CH2Cl2); complex 4 is eluted from a solution of dichloromethane (CH2Cl2) and anhydrous ethanol (CH3CH2OH) in a volume ratio of 80:1.

[0034] Furthermore, the four complexes with different configurations obtained after elution and separation were crystallized. The specific method of crystallization is as follows: in an ethanol / ethyl acetate / dichloromethane solution with a solvent volume ratio of 1:1 to 3:1, the solvent is slowly evaporated to obtain regularly shaped orange / brown-red crystals.

[0035] Furthermore, during the crystallization, the volume ratio of ethanol to ethyl acetate is 2:1, and the volume ratio of ethyl acetate to dichloromethane is 1:1; the obtained crystals are single crystals.

[0036] The present invention also provides the use of the metal carbonyl Mn complex with a 2-pyridinecarboxylic acid derivative as a ligand in preparing a donor for controllable CO release induced by visible light or near-infrared light.

[0037] The present invention also provides the use of the metal carbonyl Mn complex with 2-pyridinecarboxylic acid derivatives as ligands in improving the water solubility of a carbon monoxide releaser CORM.

[0038] The present invention also provides the use of the metal carbonyl Mn complex with 2-picolinic acid derivatives as ligands in the preparation of serum albumin complexes.

[0039] The present invention also provides the use of the metal carbonyl Mn complex with 2-pyridinecarboxylic acid derivatives as ligands in screening or preparing anti-tumor lead compounds.

[0040] Furthermore, the complex is used in screening or preparing drugs for inhibiting the growth of human cervical cancer cells.

[0041] The metal carbonyl Mn complex prepared by the present invention with a 2-pyridinecarboxylic acid derivative as a ligand can realize controllable release of CO under different light wavelengths, which is convenient for developing a carbon monoxide donor released by visible light or near-infrared light.

[0042] The four complexes with different substituent groups prepared by the present invention were tested experimentally, and the results showed that they had significant activity in inhibiting the growth of human cervical cancer cells. The IC values ​​of the complexes (ad) under light-shielding conditions were 50The values ​​were 24.231 µM, 40.118 µM, 41.362 µM, and 20.455 µM, respectively. The IC values ​​of the complex (ad) under light conditions 50 The water solubility of complexes ad is 9.147 μM, 16.152 μM, 10.559 μM, and 3.053 μM, respectively, which can be used in the preparation of anti-tumor drugs. At the same time, complexes ad have relatively good water solubility, and the water solubility of complex c can reach 30 mmol·L -1 ; In addition, complex ad can effectively release carbon monoxide under different light source irradiation conditions, and the controllable release of carbon monoxide can be achieved by regulating the wavelength of the light source. It can be used in the preparation of exogenous carbon monoxide donor reagents and is suitable for solution systems and cell systems; therefore, by preparing a carbon monoxide release rate, the visible light-induced release agent can be conveniently regulated, and this type of complex has potential application prospects in the biomedicine field.

[0043] Compared with the prior art, the four complexes of different substituent groups of the present invention have higher water solubility and have obvious effects in improving the water solubility of CORM, which provides a basis for it to become a CORM with good biocompatibility. The four complexes can realize the controllable release of CO under different irradiation wavelength conditions, and realize light release close to the near-infrared light region, thereby reducing the harm of short-wavelength light to organisms. This property is expected to be applied in the biomedical field. The four new complexes can bind to human serum proteins and can be used in the preparation of serum protein complexes, as well as in the metabolic regulation of complexes and cell-targeted delivery. Serum albumin can be used as a carrier of this type of complex in biomedicine. In addition, the four new complexes have the activity of significantly inhibiting the growth of human cervical cancer cell HeLa cells and can be used in the screening and preparation of lead compounds for anti-tumor drugs. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The crystal structures of four metal carbonyl manganese complexes of the present invention are shown in FIG. 1 ; (a) is [Mn(CO)3(2-PA)Br]; (b) is [Mn(CO)3(5-Cl-2-PA)Br]; (c) is [Mn(CO)3(5-Br-2-PC)Br]; and (d) is [Mn(CO)3(6-Br-M-2-PC)Br];

[0045] Figure 2 The NMR spectra of two metal carbonyl manganese complexes of the present invention are shown in FIG. 1 : (a) is [Mn(CO)3(2-PA)Br]; (b) is [Mn(CO)3(5-Cl-2-PA)Br];

[0046] Figure 3The NMR spectra of two metal carbonyl manganese complexes of the present invention are shown in FIG. 1 : (c) is [Mn(CO)3(5-Br-2-PC)Br]; (d) is [Mn(CO)3(6-Br-M-2-PC)Br];

[0047] Figure 4 The following are time-resolved infrared spectra of four metal carbonyl manganese complexes of the present invention under 420 nm wavelength light. In the figure: (a) is the time-resolved infrared spectrum of [Mn(CO)3(2-PA)Br] under 420 nm light; (b) is the time-resolved infrared spectrum of [Mn(CO)3(5-Cl-2-PA)Br] under 420 nm light; (c) is the time-resolved infrared spectrum of [Mn(CO)3(5-Br-2-PC)Br] under 420 nm light; (d) is the time-resolved infrared spectrum of [Mn(CO)3(6-Br-M-2-PC)Br] under 420 nm light.

[0048] Figure 5 The following are time-resolved infrared spectra of four metal carbonyl manganese complexes of the present invention under 600 nm wavelength illumination. In the figure: (a) is the time-resolved infrared spectrum of [Mn(CO)3(2-PA)Br] under 600 nm illumination; (b) is the time-resolved infrared spectrum of [Mn(CO)3(5-Cl-2-PA)Br] under 600 nm illumination; (c) is the time-resolved infrared spectrum of [Mn(CO)3(5-Br-2-PC)Br] under 600 nm illumination; (d) is the time-resolved infrared spectrum of [Mn(CO)3(6-Br-M-2-PC)Br] under 600 nm illumination.

[0049] Figure 6 This figure shows the kinetic analysis of CO release from two metal carbonyl manganese complexes of the present invention under different wavelengths of illumination. In the figure: (a) shows the fitted kinetic curves and constants for [Mn(CO)3(2-PA)Br] under 420 nm and 600 nm illumination; (b) shows the fitted kinetic curves and constants for [Mn(CO)3(5-Cl-2-PA)Br] under 420 nm and 600 nm illumination.

[0050] Figure 7 This figure shows the kinetic analysis of CO release from two metal carbonyl manganese complexes of the present invention under different wavelengths of illumination. In the figure: (c) shows the fitted kinetic curves and constants for [Mn(CO)3(5-Br-2-PC)Br] under 420 nm and 600 nm illumination; (d) shows the fitted kinetic curves and constants for [Mn(CO)3(6-Br-M-2-PC)Br] under 420 nm and 600 nm illumination.

[0051] Figure 8 The maximum solubility curves of the four metal carbonyl manganese complexes of the present invention in aqueous solution are shown in the figure. In the figure: (a) is a linear regression equation diagram of [Mn(CO)3(2-PA)Br] in aqueous solution and a UV absorption spectrum diagram of a saturated solution of the complex; (b) is a linear regression equation diagram of [Mn(CO)3(5-Cl-2-PA)Br] in aqueous solution and a UV absorption spectrum diagram of a saturated solution of the complex; (c) is a linear regression equation diagram of [Mn(CO)3(5-Br-2-PC)Br] in aqueous solution and a UV absorption spectrum diagram of a saturated solution of the complex; (d) is a linear regression equation diagram of [Mn(CO)3(6-Br-M-2-PC)Br] in aqueous solution and a UV absorption spectrum diagram of a saturated solution of the complex;

[0052] Figure 9 The fluorescence spectra and solution constant fitting curves of the binding of two metal carbonyl manganese complexes of the present invention to human serum albumin (HSA) are shown in the figure: (a) is a complex of [Mn(CO)3(2-PA)Br] and HSA; (b) is a complex of [Mn(CO)3(5-Cl-2-PA)Br] and HSA;

[0053] Figure 10 The fluorescence spectra and solution constant fitting curves of the binding of two metal carbonyl manganese complexes of the present invention to human serum albumin (HSA) are shown in FIG. (c) shows a complex of [Mn(CO)3(5-Br-2-PC)Br] and HSA; (d) shows a complex of [Mn(CO)3(6-Br-M-2-PC)Br] and HSA;

[0054] Figure 11 The effects of the four metal carbonyl manganese complexes of the present invention on the proliferation of HeLa tumor cells; in the figure: (a) [Mn(CO)3(2-PA)Br] and HeLa cells; (b) [Mn(CO)3(5-Cl-2-PA)Br] and HeLa cells; (c) [Mn(CO)3(5-Br-2-PC)Br] and HeLa cells; (d) [Mn(CO)3(6-Br-M-2-PC)Br] and HeLa cells. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0056] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the disclosure and materials cited therein are hereby incorporated by reference.

[0057] Technical equivalents to the specific embodiments described that are apparent to those skilled in the art using no more than routine experimentation are intended to be encompassed by this application.

[0058] The experimental methods in the following examples, unless otherwise specified, are all conventional methods. The instruments and equipment used in the following examples, unless otherwise specified, are all conventional laboratory instruments and equipment; the experimental materials used in the following examples, unless otherwise specified, are all purchased from conventional biochemical reagent stores.

[0059] Example 1: A novel metal carbonyl Mn complex with Mn(CO)5Br as a reactant and 2-picolinic acid (2-PA) derivatives as ligands. The chemical formula of the manganese carbonyl complex is [Mn(CO)3(L)Br], where L is 2-picolinic acid, 5-Cl-2-picolinic acid, 5-Br-2-pyridinecarboxaldehyde, and 6-Br-2-picolinic acid methyl ester.

[0060] The specific preparation method is as follows:

[0061] (1) Preparation of [Mn(CO)3(L)Br] metal manganese carbonyl complex: Dissolve 2 mmol of Mn(CO)5Br reactant and an equimolar amount of L ligand (L is 2-picolinic acid, 5-Cl-2-picolinic acid, 5-Br-2-pyridinecarboxaldehyde, or 6-Br-2-picolinic acid methyl ester) in 50 mL of a methanol:n-hexane (4:1) solvent system according to the metal Mn coordination mode. Mix the two, stir thoroughly, and heat under reflux in a 65°C water bath for 2 h. After the reaction is completed, evaporate under reduced pressure, remove the solvent, and dry under vacuum to obtain a crude product of the metal carbonyl Mn complex coordinated by mixed ligands.

[0062] (2) Separation and purification of four complexes with different configurations: The crude product of the mixed ligand-coordinated metal carbonyl Mn complex obtained in step (1) was dissolved and separated by silica gel column chromatography: eluted with solutions of different polarities consisting of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) or anhydrous ethanol (CH3CH2OH); wherein: complex 1 was eluted with a solution having a volume ratio of CH2Cl2 to CH3OH of 50:1; complex 2 was eluted with a solution having a volume ratio of CH2Cl2 to CH3OH of 100:1; complex 3 was obtained by pure CH2Cl2 and direct elution; and complex 4 was eluted with a solution having a volume ratio of CH2Cl2 to CH3CH2OH of 80:1.

[0063] (3) Spectral analysis of four metal carbonyl manganese complexes with different configurations: The four complexes purified in step (2) were subjected to structural analysis and identification using structural characterization methods such as nuclear magnetic resonance spectroscopy, infrared spectroscopy and X-ray crystal diffraction. The crystal structures of the four metal carbonyl manganese complexes are shown in Figure 2. Figure 1 As shown, the NMR spectrum is Figure 2 、 Figure 3 shown.

[0064] Complex 1: Nuclear magnetic resonance NMR spectrum 600M ( d 6-DMSO): δ 8.98 (d, J = 2.6 Hz), 8.18 (t, J = 3.8 Hz), 7.98 (d, J = 3.8 Hz), 7.77 (t, J = 3.2 Hz). KBr pellet FT-IR ( d 6-DMSO) spectrum: v CO (cm -1 ): 2029, 2016, 1916.

[0065] Complex 2: Nuclear magnetic resonance NMR spectrum 600M ( d 6-DMSO): δ 9.01 (d, J = 1.1 Hz), 8.32(dd, J = 4.1, 1.2 Hz), 7.97 (d, J = 4.1 Hz). KBr pellet FT-IR ( d 6-DMSO) spectrum: v CO (cm -1 ):2030, 2018, 1922.

[0066] Complex 3: Nuclear magnetic resonance NMR spectrum 600M ( d 6-DMSO): δ 9.95 (s, 1H), 8.97 (s, 1H), 8.32 (d, J = 8.1 Hz, 1H), 7.87 (d, J = 8.1 Hz, 1H). KBr pellet FT-IR ( d 6-DMSO) spectrum: v CO (cm -1 ): 2032, 2023, 1912

[0067] Complex 4: 1 H NMR (600 MHz, DMSO- d 6): δ 8.07 (d, J = 7.1 Hz, 1H), 7.92 (dd, J = 18.9, 7.6 Hz, 2H), 3.88 (s, 3H). KBr pellet FT-IR ( d 6-DMSO) spectrum: v CO (cm -1 ) :2031, 2022, 1915.

[0068] Example 2: Preparation of Single Crystals of Four Metal Manganese Carbonyl Complexes with Different Structures. The four complexes with different structures obtained after separation were crystallized. The crystallization method is as follows: In a solvent solution of ethanol / ethyl acetate and dichloromethane with a volume ratio of 1:1 to 3:1, the volume ratio of ethyl acetate to dichloromethane is 1:1.

[0069] Crystals suitable for X-ray crystallography were prepared by slow evaporation using appropriate solvent evaporation rates, depending on the complex. Complex (a) grew into diamond-shaped, dark brown single crystals after overnight incubation in dichloromethane:methanol (1:2); complex (b) grew into long, pale yellow single crystals after two days incubation in ethyl acetate:methanol (2:3); complex (c) grew into blocky, dark brown single crystals after 1.5 days incubation in dichloromethane:ethyl acetate (1:3); and complex (d) grew into long, dark brown single crystals after overnight incubation in dichloromethane:acetone (1:2).

[0070] The atomic resolution structure of the complex was determined using a single crystal X-ray diffractometer to obtain its accurate spatial configuration. Data were collected using a Bruker D8 Venture diffractometer at room temperature (298 K). The radiation source was Mo-Kα rays monochromated by a graphite monochromator with a wavelength of 0.71073 Å. The unit cell parameters were determined and the data were reduced by running the SAINT program in SMART software. The structural analysis was completed using the SHELXTL-14 program package. The crystal structure of the complex is shown in the attached figure. Figure 1 As shown, the three-dimensional structures of the four new metal carbonyl Mn complexes are as follows:

[0071]

[0072] (a) is [Mn(CO)3(2-PA)Br]; (b) is [Mn(CO)3(5-Cl-2-PA)Br]; (c) is [Mn(CO)3(5-Br-2-PC)Br]; (d) is [Mn(CO)3(6-Br-M-2-PC)Br].

[0073] In (a), (b), (c) and (d), the N and O of the pyridine derivative ligands coordinate with the metal Mn ion respectively, and the Mn center presents a hexacoordinated octahedral geometric structure, which also includes 3 CO ligands and 1 bromine atom. Among them, the crystal of complex (a) belongs to the monoclinic system, and the space group is P 21 / c; Compared with complex (a), complex (b) replaces a Cl atom at the 5-position of pyridine. Its crystal belongs to the triclinic system and the space group is P 1; Complex (c) is a 2-pyridinecarboxaldehyde ligand, with a Br atom replacing the 5th position. The crystal is the same as (b) in the triclinic system, with a space group of P 1; and complex (d) is a methyl picolinate ligand, with the 6th position replaced by a Br atom. Like (a), it is a monoclinic crystal system, and its space group is C 2 / c, which forms four complexes with four different structures, and their different substituent groups bring about differences in their properties.

[0074] Example 3: The kinetics of CO release can be monitored by measuring the time-resolved infrared spectra of the complexes. The effects of different wavelengths of light on the CO release rates of four metal manganese carbonyl complexes were studied. The logarithm (lnA) of the absorbance of the four complexes after irradiation with different wavelengths was taken, and the relationship with time (t) was linear. The CO release kinetics of the four complexes under 420 nm and 600 nm wavelengths of light are shown in the following table. Figure 6 、 Figure 7 As shown.

[0075] Calculations of the half-lives of the four complexes under 420 nm illumination reveal that their release rates at 420 nm are (c) < (b) < (d) < (a), and at 600 nm are (c) < (b) < (a) < (d). This result is likely due to the different absorption capacities of different substances for light of different wavelengths. These results suggest that controlled CO release from metal carbonyl complexes can be achieved by varying the wavelength of the light source.

[0076] Example 4: The four metal carbonyl manganese complexes of the present invention are easily soluble in organic solvents. However, for complex drugs, having appropriate water solubility will have wider application value. Use DMSO to prepare a [Mn(CO)3(L)Br] solution of known concentration. First, add 2 mL of H2O to the cuvette, and then add 10 μL of the [Mn(CO)3(L)Br] solution of known concentration. The concentrations in the cuvette after dilution are 50, 100, 150, 200, 250, and 300 μmol·L -1 The absorbance values ​​at the corresponding concentrations after dilution were linearly fitted, and then the absorbance of the supersaturated solution of the complex aqueous solution was measured. The maximum solubility of the complex in water was finally obtained by calculating with the offline regression equation. The results are as follows Figure 8 (a) shows the linear regression equation of [Mn(CO)3(2-PA)Br] in aqueous solution and the UV absorption graph of the saturated solution of the complex. The linear regression equation of CA of the complex is y=0.00402x+0.00127, and the maximum water solubility is 1930 μmol·L -1 (b) shows the linear regression equation of [Mn(CO)3(5-Cl-2-PA)Br] in aqueous solution and the UV absorption graph of the complex's saturated solution. The linear regression equation for CA of the complex is y=0.00388x+0.01076, and the maximum water solubility is 411.44 μmol·L -1 (c) shows the linear regression equation of [Mn(CO)3(5-Br-2-PC)Br] in aqueous solution and the UV absorption graph of the complex's saturated solution. The linear regression equation for CA of the complex is y=0.00159x+0.01075, and the maximum water solubility is 30567 μmol·L -1 (d) shows the linear regression equation of [Mn(CO)3(6-Br-M-2-PC)Br] in aqueous solution and the UV absorption graph of the complex's saturated solution. The linear regression equation for CA of the complex is y=0.00117x+0.02239, and the maximum water solubility is 926.2 μmol·L -1 The experimental results show that the solubility of the complexes is (c) > (a) > (d) > (b), among which complex (c) [Mn(CO)3(5-Br-2-PC)Br] has the highest water solubility, which has a significant effect in improving the water solubility of CORM.

[0077] Example 5: Serum albumin (HSA) is the most abundant protein in human blood. It is also a carrier of many endogenous and exogenous bioactive small molecules, including some drug molecules. After binding, the new complex can not only increase water solubility and improve drug metabolic kinetics, but also reduce potential drug toxicity.

[0078] The four metal carbonyl manganese complexes of the present invention can bind to human serum albumin (HSA) and Figure 9 、 Figure 10 The fluorescence spectra and solution constant fitting curves of the metal carbonyl manganese complex and HSA are shown. Binding of these molecules to human serum albumin can improve the selectivity and bioavailability of the complex in vivo, demonstrating promising applications. Binding of the complex to serum albumin may alter its pharmacokinetic profile, thereby reducing toxic side effects and improving therapeutic efficacy.

[0079] According to the formula The binding constants of complexes 1~4 with HSA were 5.37×10 4 , 2.35×10 6 , 1.92×10 6 , 2.61×10 6 Based on this, the order of binding strength between the complexes and HSA is: complex 4 > complexes 1 and 3, with complexes 2 and 4 being similar. The number of binding sites is approximately 1. These results demonstrate that all four complexes prepared by the present invention can bind well to serum albumin, improving their selectivity and bioavailability in vivo and demonstrating their potential for application.

[0080] Example 6: Inhibitory activity of four metal carbonyl manganese complexes on HeLa cell growth under dark and light conditions. The complex samples were dissolved in DMSO as the mother solution, and the cytotoxicity of the complexes was tested using the CCK8 method. (a) 1, 5, 10, 20, 50, 60, 80, and 100 μM complex solutions were added to a 96-well plate. The light and dark groups were operated in the same way; the cell culture plate was placed in a 37°C, 5% CO2 cell culture incubator for 2 hours, and then a cell plate was taken out as the light group and placed under a 420 nm LED dedicated light source with a voltage of 21.7 V for 10 minutes, and then returned to the cell culture incubator for incubation for 24 hours; after the incubation time, the culture plate was removed, 10 μL of CCK-8 solvent was added to each well, and the plate was taken out after incubation for another 3 hours. The absorbance at 450 nm was measured by an enzyme reader, and the inhibition rate was calculated and statistically plotted. The results are shown as follows Figure 11 shown.

[0081] The above experiments show that the four metal carbonyl Mn complexes have significant inhibitory activity on the growth of HeLa cells. They have significant inhibitory activity on the growth of human cervical cancer cells before and after illumination. The IC values ​​of complexes 1-4 under light-shielded conditions are 50 The values ​​were 24.231 µM, 40.118 µM, 41.362 µM, and 20.455 µM, respectively. The IC values ​​of complexes 1-4 under light conditions were 50The values ​​were 9.147 µM, 16.152 µM, 10.559 µM, and 3.053 µM, respectively. These complexes are potentially useful in the screening and preparation of lead anti-tumor compounds. All four complexes exhibited relatively good photocatalytic release activity, enabling regulated release of CO donors under different conditions. Furthermore, the complexes bound to serum albumin can serve as a carrier for the complexes, potentially enabling biomedical applications.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A metal carbonyl Mn complex with a 2-pyridinecarboxylic acid derivative as a ligand, characterized in that: The chemical formula of the metal carbonyl Mn complex is [Mn(CO)3(L)Br], wherein L is 2-pyridinecarboxylic acid, 5-Cl-2-pyridinecarboxylic acid, 5-Br-2-pyridinecarboxaldehyde or 6-Br-2-pyridinecarboxylic acid methyl ester, and the stereostructure of the metal carbonyl Mn complex is as follows: 。 2. A method for preparing the metal carbonyl Mn complex with a 2-pyridinecarboxylic acid derivative as a ligand according to claim 1, characterized in that: Using Mn(CO)5Br as a reactant and 2-picolinic acid derivatives as ligands, carbonyl complexes with different ligands having hexacoordinated and octahedral structures are prepared through synthetic reaction and fine separation; wherein the 2-picolinic acid derivatives are 2-picolinic acid, 5-Cl-2-picolinic acid, 5-Br-2-pyridinecarboxaldehyde or 6-Br-2-picolinic acid methyl ester.

3. The preparation method according to claim 2, wherein: The specific steps are as follows: (1) Synthesis of [Mn(CO)3(L)Br] metal carbonyl Mn complex: According to the coordination mode of metal Mn, 2 mmol of Mn(CO)5Br reactant and an equal molar amount of 2-pyridinecarboxylic acid derivative ligand were dissolved in 50 mL of a solvent system of methanol:n-hexane with a volume ratio of 4:

1. The two were mixed, stirred thoroughly, and heated to reflux in a water bath at 65°C for 2 h. After the reaction, the solvent was removed by vacuum distillation, and the sample was placed in a vacuum drying dish and dried to obtain a crude product of the metal carbonyl Mn complex coordinated by mixed ligands. (2) The crude product of the metal carbonyl Mn complex coordinated by the mixed ligand obtained in step (1) is dissolved in dichloromethane and separated by silica gel column chromatography; wherein: complex (a) is eluted from a mixed solution of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) in a volume ratio of 50:1; complex (b) is eluted from a mixed solution of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) in a volume ratio of 100:1; complex (c) is directly eluted from pure dichloromethane (CH2Cl2); and complex (d) is eluted from a solution of dichloromethane (CH2Cl2) and anhydrous ethanol (CH3CH2OH) in a volume ratio of 80:

1.

4. The preparation method according to claim 3, wherein: The four complexes with different configurations obtained after elution and separation were crystallized. The specific method of crystallization is: in an ethanol / ethyl acetate / dichloromethane solution with a solvent volume ratio of 1:1 to 3:1, the solvent is slowly evaporated to obtain regularly shaped orange / brown-red crystals.

5. The preparation method according to claim 4, characterized in that: The volume ratio of ethanol to ethyl acetate is 2:1, and the volume ratio of ethyl acetate to dichloromethane is 1:1; the obtained crystals are single crystals.

6. Use of the metal carbonyl Mn complex with a 2-pyridinecarboxylic acid derivative as a ligand according to claim 1 in the preparation of a donor for controlled release of CO induced by visible light or near-infrared light.

7. Use of the metal carbonyl Mn complex with a 2-pyridinecarboxylic acid derivative as a ligand according to claim 1 in improving the water solubility of a carbon monoxide releaser (CORM).

8. Use of the metal carbonyl Mn complex with a 2-picolinic acid derivative as a ligand according to claim 1 in the preparation of a serum albumin complex.

9. Use of the metal carbonyl Mn complex with a 2-pyridinecarboxylic acid derivative as a ligand according to claim 1 in screening or preparing anti-tumor lead compounds.

10. The use according to claim 9, characterized in that: The complex is used in screening or preparing drugs for inhibiting the growth of human cervical cancer cells.

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