Metal carbonyl Mn complex taking 2-picolinic acid derivative as ligand as well as preparation method and application of metal carbonyl Mn complex

Abstract

The invention belongs to the technical field of synthesis and application of complexes, and provides a metal carbonyl Mn complex taking a 2-picolinic acid derivative as a ligand as well as a preparation method and application of the metal carbonyl Mn complex. The chemical formula of the complex is [Mn (CO) 3 (L) Br], L is 2-picolinic acid, 5-Cl-2-picolinic acid, 5-Br-2-pyridylaldehyde or 6-Br-2-picolinic acid methyl ester, and the complex with four different substituent groups has high water solubility and has an obvious effect on improving the water solubility of CORM. The four complexes can realize CO controllable release under different illumination wavelengths, and can be applied to preparation of donors capable of realizing CO controllable release in visible light or near-infrared light. The compound can be combined with human serum protein to prepare a serum protein complex, and can be applied to metabolism regulation and cell targeting carrying of the complex. The growth of human cervical cancer HeLa cells is obviously inhibited, and the compound can be applied to screening and preparation of lead compounds of anti-tumor drugs.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthesis and application of complexes, and specifically relates to a metal carbonyl Mn complex with a 2-pyridinecarboxylic acid derivative as a ligand, a preparation method and application thereof; more specifically, a novel metal carbonyl Mn complex with Mn(CO)5Br as a reactant and a 2-pyridinecarboxylic acid derivative as a ligand, a preparation method and application thereof, the prepared metal carbonyl Mn complex having four different structures, and the application of the metal carbonyl Mn complex in screening and preparing 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 type of 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-pyridinecarboxylic acid derivative as a ligand can be used in screening and preparing 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 of CORM release CO include ligand substitution, pH triggering, enzyme triggering, and light induction [3-6]. Among them, photo-triggered CORM (PhotoCORM), that is, light-induced carbon monoxide release, has unique advantages. Different intensity light sources and different wavelengths of light 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. Metallic 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, and induce macrophages to resist cancer cells, thereby achieving the purpose of anti-tumor. Studies have shown that picolinic acid and its derivatives have a certain effect in 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 some 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 functional ingredients in health foods

[16] . 2-picolinic acid ligands have different functional coordination atoms N and O at the same time. They 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, which improves the selectivity and bioavailability of the complex in vivo and has 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: [1] Marks GS, Brien JF, Nakatsu K, McLaughlin BE. Does carbonmonoxide have a physiological function? Trends Pharmacol Sci. 1991; 12(5):185-8. [2] Cheng J, Hu J. Recent Advances on Carbon Monoxide ReleasingMolecules for Antibacterial Applications. ChemMedChem. 2021; 16(24): 3628-3634. [3] Heinemann SH, Hoshi T, Westerhausen M, Schiller A. Carbonmonoxide--physiology, detection and controlled release. Chem Commun (Camb).2014; 50(28): 3644-60. [4] Schatzschneider U. Novel lead structures and activationmechanisms for CO-releasing molecules (CORMs). Br J Pharmacol. 2015;172(6):1638-50. [5] Ford P C. Metal complex strategies for photo-uncaging the smallmolecule bioregulators nitric oxide and carbon monoxide[J]. Coord Chem Rev.2018; 376: 548-564. [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. [7] Lazarus LS, Benninghoff AD, Berreau LM. Development ofTriggerable, Trackable, and Targetable Carbon Monoxide Releasing Molecules.Acc Chem Res. 2020; 53(10): 2273-2285. [8] Ford P C. Metal complex strategies for photo-uncaging the smallmolecule bioregulators nitric oxide and carbon monoxide . Coord Chem Rev.2018; 376: 548-564. [9] Ustun E, Ozgur A, Coskun K A. Anticancer activities of manganese-based photoactivatable CO-releasing complexes (PhotoCORMs) with benzimidazolederivative ligands. Transit Metal Chem. 2017; 42(4):331-337.

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

[11] Poynton FE, Bright SA, Blasco S, Williams DC, Kelly JM,Gunnlaugsson T. The development of ruthenium(ii) polypyridyl complexes andconjugates for in vitro cellular and in vivo applications. Chem Soc Rev.2017; 46(24): 7706-7756.

[12] Rathgeb A, Böhm A, Novak MS, Gavriluta A, Dömötör O, TommasinoJB, 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 diffractionstructures, spectroscopic and electrochemical properties, andantiproliferative activity. Inorg Chem. 2014; 53(5): 2718-29.

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

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

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

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

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

[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.

[19] Parodi A, Miao J, Soond SM, Rudzińska M, Zamyatnin AA Jr. Albumin Nanovectors in Cancer Therapy and Imaging. Biomolecules. 2019; 9(6):218.

[20] Liu X, Mohanty RP, Maier EY, Peng X, Wulfe S, Looney AP, AungKL, 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 of the invention

[0006] The purpose of the present invention is to provide a metal carbonyl Mn complex with 2-pyridine carboxylic acid derivatives as ligands, a preparation method and application thereof, and more specifically, to provide a novel metal carbonyl Mn complex with Mn(CO)5Br as reactant and 2-pyridine carboxylic acid derivatives as ligands, a preparation method and application thereof, wherein the metal carbonyl complex is a complex with 2-pyridine carboxylic acid derivatives as ligands and Mn as a central element for coordination, and forms a six-coordinated octahedral structure, and four metal carbonyl manganese complexes with different substituent groups are prepared through synthetic reaction and fine separation. The reactivity of each complex shows certain differences.

[0007] The present invention also provides a metal carbonyl manganese complex as a CO donor, and controllable regulation of the release rate of the signal molecule at different light wavelengths. The present invention provides the possibility of improving the water solubility of CORM by metal carbonyl manganese complexes. The present invention provides a metal carbonyl manganese complex combined with human serum albumin, which improves the selectivity and bioavailability of the complex in vivo, and has certain application value. The present invention also provides the application of such metal carbonyl manganese complexes in anti-tumor compound drug screening.

[0008] The present invention is achieved by the following technical scheme: a metal carbonyl Mn complex with a 2-pyridinecarboxylic acid derivative as a ligand, 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: The present invention also provides a method for preparing the metal carbonyl Mn complex with 2-pyridinecarboxylic acid derivatives as ligands, using Mn(CO)5Br as a reactant and 2-pyridinecarboxylic acid derivatives as ligands, and preparing carbonyl complexes with different ligands of hexacoordinated and octahedral structures through synthetic reaction and fine separation; wherein: the 2-pyridinecarboxylic acid derivative is 2-pyridinecarboxylic acid, 5-Cl-2-pyridinecarboxylic acid, 5-Br-2-pyridinecarboxaldehyde or 6-Br-2-pyridinecarboxylic acid methyl ester.

[0009] Further, 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, mixed, stirred thoroughly, and heated to reflux at 65 °C for 2 h. After the reaction was completed, 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 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 then separated by silica gel column chromatography; wherein: complex 1 is obtained by eluting with a mixed solution of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) in a volume ratio of 50:1; complex 2 is obtained by eluting with a mixed solution of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) in a volume ratio of 100:1; complex 3 is obtained by directly eluting with pure dichloromethane (CH2Cl2); and complex 4 is obtained by eluting with a solution of dichloromethane (CH2Cl2) and anhydrous ethanol (CH3CH2OH) in a volume ratio of 80:1.

[0010] Furthermore, the four complexes with different configurations obtained after elution and separation are crystallized. The specific method of crystallization is: in an ethanol / ethyl acetate / dichloromethane solution with a solvent volume ratio of 1:1-3:1, the solvent is controlled to evaporate slowly to obtain orange / brown-red crystals with regular shapes.

[0011] 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.

[0012] The present invention also provides the use of the metal carbonyl Mn complex with 2-pyridinecarboxylic acid derivatives as ligands in preparing a donor for controllable release of CO induced by visible light or near infrared light.

[0013] The present invention also provides the use of the metal carbonyl Mn complex with 2-pyridine carboxylic acid derivatives as ligands in improving the water solubility of carbon monoxide release agent CORM.

[0014] The present invention also provides the use of the metal carbonyl Mn complex with 2-pyridinecarboxylic acid derivatives as ligands in the preparation of serum albumin complexes.

[0015] 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.

[0016] Furthermore, the complex is used in screening or preparing drugs for inhibiting the growth of human cervical cancer cells.

[0017] The metal carbonyl Mn complex prepared by the present invention with 2-pyridine carboxylic acid derivatives as ligands can realize the controllable release of CO under different light wavelengths, which is convenient for developing carbon monoxide donors released by visible light or near-infrared light.

[0018] The four complexes with different substituent groups prepared by the present invention were tested experimentally, and the results showed that they had obvious activity in inhibiting the growth of human cervical cancer cells. The IC of the complex (ad) under light-proof conditions was 50 The values ​​were 24.231 µM, 40.118 µM, 41.362 µM, and 20.455 µM, respectively. IC of the complex (ad) under light conditions 50 The water solubility of complex 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 that can be conveniently regulated by visible light-induced releasers, this type of complex has potential application prospects in the biomedical field.

[0019] 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 wavelengths, and realize the 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 be combined with 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 cells HeLa cells, and can be used in the screening and preparation of anti-tumor drug lead compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The crystal structures of four metal carbonyl manganese complexes of the present invention are shown in the figure: (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]; 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]; Figure 3 The 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]; Figure 4 The present invention shows time-resolved infrared spectra of four metal carbonyl manganese complexes under 420 nm wavelength illumination; in the figure: (a) is the time-resolved infrared spectrum of [Mn(CO)3(2-PA)Br] under 420 nm illumination; (b) is the time-resolved infrared spectrum of [Mn(CO)3(5-Cl-2-PA)Br] under 420 nm illumination; (c) is the time-resolved infrared spectrum of [Mn(CO)3(5-Br-2-PC)Br] under 420 nm illumination; (d) is the time-resolved infrared spectrum of [Mn(CO)3(6-Br-M-2-PC)Br] under 420 nm illumination; Figure 5The time-resolved infrared spectra of four metal carbonyl manganese complexes of the present invention under 600 nm wavelength light; in the figure: (a) is the time-resolved infrared spectrum of [Mn(CO)3(2-PA)Br] under 600 nm light; (b) is the time-resolved infrared spectrum of [Mn(CO)3(5-Cl-2-PA)Br] under 600 nm light; (c) is the time-resolved infrared spectrum of [Mn(CO)3(5-Br-2-PC)Br] under 600 nm light; (d) is the time-resolved infrared spectrum of [Mn(CO)3(6-Br-M-2-PC)Br] under 600 nm light; Figure 6 The figure shows the kinetic analysis of CO release of two metal carbonyl manganese complexes under different wavelengths of illumination. In the figure: (a) is the fitting kinetic curve and constant of [Mn(CO)3(2-PA)Br] under 420 nm and 600 nm illumination conditions; (b) is the fitting kinetic curve and constant of [Mn(CO)3(5-Cl-2-PA)Br] under 420 nm and 600 nm illumination conditions; Figure 7 The figure shows the kinetic analysis of CO release of two metal carbonyl manganese complexes under different wavelengths of illumination. In the figure: (c) shows the fitting kinetic curve and constant of [Mn(CO)3(5-Br-2-PC)Br] under 420 nm and 600 nm illumination; (d) shows the fitting kinetic curve and constant of [Mn(CO)3(6-Br-M-2-PC)Br] under 420 nm and 600 nm illumination. Figure 8 The maximum solubility curves of the four metal carbonyl manganese complexes of the present invention in aqueous solution; 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; Fig. 9 The fluorescence spectra and the solution and constant fitting curves of the binding of two metal carbonyl manganese complexes of the present invention with human serum albumin (HSA); 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; Fig.10 The fluorescence spectra and the solution and constant fitting curves of the binding of two metal carbonyl manganese complexes of the present invention with human serum albumin (HSA); in the figure: (c) is a complex of [Mn(CO)3(5-Br-2-PC)Br] and HSA; (d) is a complex of [Mn(CO)3(6-Br-M-2-PC)Br] and HSA; Fig.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

[0021] 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, rather than 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.

[0022] 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.

[0023] 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.

[0024] The experimental methods in the following examples are all conventional methods unless otherwise specified. The instruments and equipment used in the following examples are all conventional laboratory instruments and equipment unless otherwise specified; the experimental materials used in the following examples are all purchased from conventional biochemical reagent stores unless otherwise specified.

[0025] Example 1: A novel metal carbonyl Mn complex with Mn(CO)5Br as reactant and 2-picolinic acid (2-PA) derivatives as ligands, the chemical formula of the manganese carbonyl complex is [Mn(CO)3(L)Br], wherein L is 2-picolinic acid, 5-Cl-2-picolinic acid, 5-Br-2-pyridinecarboxaldehyde, and 6-Br-2-picolinic acid methyl ester.

[0026] The specific preparation method is as follows: (1) Preparation of [Mn(CO)3(L)Br] metal manganese carbonyl complex: According to the coordination mode of metal Mn, 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, 6-Br-2-picolinic acid methyl ester) were dissolved in 50 mL of methanol:n-hexane (4:1) solvent system, mixed, stirred thoroughly, and heated to reflux in a water bath at 65 °C for 2 h. After the reaction was completed, the reaction was evaporated under reduced pressure, the solvent was removed, and then vacuum dried to obtain a crude product of metal carbonyl Mn complex coordinated by mixed ligands; (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) is dissolved and separated by silica gel column chromatography: elution is performed using solutions of different polarities composed of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) or anhydrous ethanol (CH3CH2OH); wherein: complex 1 is obtained by eluting with a solution in which the volume ratio of CH2Cl2 to CH3OH is 50:1; complex 2 is obtained by eluting with a solution in which the volume ratio of CH2Cl2 to CH3OH is 100:1; complex 3 is obtained by eluting with pure CH2Cl2 and directly; complex 4 is obtained by eluting with a solution in which the volume ratio of CH2Cl2 to CH3CH2OH is 80:1.

[0027] (3) Spectral analysis of four metal carbonyl manganese complexes with different configurations: The four complexes purified in step (2) were analyzed and identified 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 in the NMR spectrum Figure 2 , Figure 3 shown.

[0028] 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.

[0029] 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.

[0030] 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 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.

[0031] Example 2: Preparation of single crystals of four metal carbonyl manganese complexes with different structures. The four complexes with different structures obtained after separation were crystallized. The specific method of crystallization is: in an ethanol / ethyl acetate and dichloromethane solution with a solvent volume ratio of 1:1 to 3:1, the volume ratio of ethyl acetate to dichloromethane is 1:1.

[0032] According to different complexes, appropriate solvent evaporation speed was selected, and crystals suitable for X-ray crystallography were prepared by slow evaporation method. After overnight culture in dichloromethane:methanol (1:2), complex (a) grew rhombus-shaped dark brown single crystals; after 2 days of culture in ethyl acetate:methanol (2:3), complex (b) grew long strip-shaped light yellow single crystals; after 1.5 days of culture in dichloromethane:ethyl acetate (1:3), complex (c) grew block-shaped dark brown single crystals; after overnight culture in dichloromethane:acetone (1:2), complex (d) grew long strip-shaped dark brown single crystals.

[0033] The atomic resolution structure was determined by X-ray single crystal diffractometer to obtain its accurate spatial configuration. The data were collected at room temperature 298 K using a Bruker D8 Venture diffractometer, with the radiation source being Mo-Kα rays monochromatized 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 SMART software SAINT program; 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 four new metal carbonyl Mn complexes are as follows: (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].

[0034] In (a), (b), (c) and (d), the N and O of the pyridine derivative ligands are coordinated 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 5th 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; while complex (d) is a methyl picolinate ligand, with the 6th position replaced by a Br atom. It is the same as (a) and is a monoclinic system. Its space group is C 2 / c, which forms four complexes with four different structures, and their different substituents bring about differences in their properties.

[0035] Example 3: The kinetic process of CO release can be detected by measuring the time-resolved infrared spectrum of carbon monoxide of the complexes, and the effect of different wavelengths of light source on the carbon monoxide release rate of four metal carbonyl manganese complexes is studied. The logarithm (lnA) of the absorbance of the above four complexes after illumination at different wavelengths is taken, which is linearly related to time (t). The CO release kinetics of the four complexes under illumination at two wavelengths of 420 nm and 600 nm are shown in the following figure: Figure 6 , Figure 7 As shown.

[0036] According to the calculation of the half-life of the four complexes under 420 nm light source, the release rate at 420 nm is: (c) < (b) < (d) < (a), and the release rate at 600 nm is: (c) < (b) < (a) < (d). This result may be caused by the different absorption abilities of different substances to light of different wavelengths. The above results show that the controllable release of CO in metal carbonyl complexes can be achieved by changing the light source of different wavelengths.

[0037] Example 4: The four metal carbonyl manganese complexes of the present invention are easily soluble in organic solvents. However, for complex drugs, they have a wider application value if they have appropriate water solubility. 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 shown in Figure 8 (a) is 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) is the linear regression equation of [Mn(CO)3(5-Cl-2-PA)Br] in aqueous solution and the UV absorption graph of the saturated solution of the complex. The CA linear regression equation of the complex is y=0.00388x+0.01076, and the maximum water solubility is 411.44 μmol·L -1(c) is the linear regression equation of [Mn(CO)3(5-Br-2-PC)Br] in aqueous solution and the UV absorption graph of the saturated solution of the complex. The CA linear regression equation of the complex is y=0.00159x+0.01075, and the maximum water solubility is 30567 μmol·L -1 (d) is the linear regression equation of [Mn(CO)3(6-Br-M-2-PC)Br] in aqueous solution and the UV absorption graph of the saturated solution of the complex. The CA linear regression equation of the complex is y=0.00117x+0.02239, and the maximum water solubility is 926.2 μmol·L -1 From the experimental results, it can be seen that the solubility of the complexes is (c)>(a)>(d)>(b), among which the water solubility of complex (c) [Mn(CO)3(5-Br-2-PC)Br] is the highest, which has a significant effect in improving the water solubility of CORM.

[0038] 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 improve water solubility and drug pharmacokinetic characteristics, but also reduce potential drug toxicity.

[0039] The four metal carbonyl manganese complexes of the present invention can bind to human serum albumin (HSA) and Fig. 9 , Fig.10 The fluorescence spectra and the solution and constant fitting curves of the metal carbonyl manganese complex and HSA are shown. These molecules bind to human serum albumin to improve the selectivity and bioavailability of the complex in vivo, and have certain application value. The binding of the complex to serum albumin may change its pharmacokinetic process, thereby reducing its toxic side effects and improving the therapeutic effect.

[0040] 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 , it can be judged that the order of binding strength between the complexes and HSA is: complex 4>1 and 3, 2 and 4 are similar. The number of binding sites is about 1. The results show that the four complexes prepared by the present invention can bind well to serum albumin, can improve the selectivity and bioavailability of the complexes in vivo, and have certain application value.

[0041] Example 6: Inhibitory activity of four metal carbonyl manganese complexes on HeLa cell growth under dark conditions and light conditions. The complex samples were dissolved in DMSO as the mother solution, and the cytotoxicity of the complex 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 h, and then a cell plate was taken out as the light group, placed under a 420 nm LED dedicated light source, the voltage was 21.7 V for 10 min, and then returned to the cell culture incubator for incubation for 24 h; after the incubation time, the culture plate was taken out, 10 µL of CCK-8 solvent was added to each well, and then incubated for another 3 h and then taken out, and the absorbance at 450 nm was measured by an enzyme marker, and the inhibition rate was calculated and statistically plotted. The results are shown as follows Fig.11 shown.

[0042] In summary, the experiments show that the four metal carbonyl Mn complexes have significant activity in inhibiting the growth of HeLa cells. They have significant activity in inhibiting the growth of human cervical cancer cells before and after illumination. The IC values ​​of complexes 1-4 under light-protected conditions are 50 The values ​​are 24.231 µM, 40.118 µM, 41.362 µM, and 20.455 µM, respectively. The IC values ​​of complexes 1-4 under light conditions are 50 The values ​​are 9.147 µM, 16.152 µM, 10.559 µM, and 3.053 µM, respectively, and can be used in the screening and preparation of anti-tumor lead compound drugs. All four complexes have relatively good photocatalytic release activity and can achieve adjustable release of CO donors under different conditions. At the same time, the complexes bound to serum albumin can be used as carriers of the complexes and can be used in biomedicine.

[0043] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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 as claimed in claim 1, characterized in that: With Mn(CO)5Br as 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, characterized in that: 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, respectively. The two were mixed, stirred thoroughly, and heated to reflux in a water bath at 65°C for 2 h. After the reaction was completed, 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 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 1 is obtained by eluting with a mixed solution of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) in a volume ratio of 50:1; complex 2 is obtained by eluting with a mixed solution of dichloromethane (CH2Cl2) and anhydrous methanol (CH3OH) in a volume ratio of 100:1; complex 3 is obtained by directly eluting with pure dichloromethane (CH2Cl2); and complex 4 is obtained by eluting with a solution of dichloromethane (CH2Cl2) and anhydrous ethanol (CH3CH2OH) in a volume ratio of 80:

1.

4. The preparation method according to claim 3, characterized in that: The four complexes with different configurations obtained after elution and separation are crystallized. The specific method of crystallization is: in an ethanol / ethyl acetate / dichloromethane solution with a solvent volume ratio of 1:1-3:1, the solvent is controlled to evaporate slowly to obtain orange / brown-red crystals with regular shapes.

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 crystal is a single crystal.

6. Use of the metal carbonyl Mn complex with 2-pyridinecarboxylic acid derivatives as ligands as claimed in 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 2-pyridinecarboxylic acid derivatives as ligands as claimed in claim 1 in improving the water solubility of carbon monoxide releaser CORM.

8. Use of the metal carbonyl Mn complex with 2-picolinic acid derivatives as ligands as claimed in claim 1 in the preparation of serum albumin complexes.

9. Use of the metal carbonyl Mn complex with 2-pyridinecarboxylic acid derivatives as ligands as claimed in 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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