Divalent metal coordination polymer and its preparation method and application

Abstract

The present invention relates to the technical field of antibacterial coordination polymers, and in particular to a divalent metal coordination polymer, its preparation method, and application. The present invention uses a one-pot hydrothermal reaction to prepare the divalent metal coordination polymer, the chemical formula of which is [Mn(cpt)2] n or [Co(cpt)2] n , [Mn(cpt)2] n The molecular formula is C 56 H 36 MnN6O6,[Co(cpt)2] n The molecular formula is C 56 H 36 CoN6O6, the preparation method has the advantages of simple process, convenient operation, high yield and good reproducibility, and the prepared [Mn(cpt)2] n and [Co(cpt)2] n It has good antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa.

Description

Technical Field

[0001] The present invention relates to the technical field of antibacterial coordination polymers, in particular to a divalent metal coordination polymer and a preparation method and application thereof. Background Art

[0002] Bacterial infections are a leading cause of death, disability, and socioeconomic loss for millions of people worldwide, a problem further compounded by the rapid spread of antibiotic-resistant microorganisms. Implant-associated bacterial infections have also become a common phenomenon, with Staphylococcus aureus and Pseudomonas aeruginosa being common pathogens causing wound infections. Staphylococcus aureus is a Gram-positive bacterium commonly found in the skin and nasal passages of asymptomatic individuals, causing a variety of infections, including dermatological conditions such as impetigo and furuncle, respiratory illnesses such as pneumonia and acute bronchitis, and cases of foodborne illness. Pseudomonas aeruginosa is a Gram-negative bacterium and an opportunistic pathogen that readily forms biofilms. It is commonly found in soil, water, and on plant surfaces, and can cause a variety of infections, particularly in immunocompromised individuals such as those with cystic fibrosis, cancer, or transplant patients. Therefore, there is an urgent need to develop effective and biologically appropriate antimicrobials to replace the use of antibiotics and limit the spread of drug-resistant bacteria.

[0003] Metal coordination polymers, characterized by their tunable porous structures, high porosity, and high specific surface area, have recently been widely used in biomedical applications, such as antibacterial therapy. These materials can store metal ions and slowly release them, achieving a sustained antibacterial effect. Manganese and cobalt are also essential trace elements for human health. In recent years, manganese(II) and cobalt(II) coordination polymers have also been widely used in the antibacterial field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a divalent metal coordination polymer and its preparation method and application in view of the above-mentioned deficiencies in the prior art, wherein the divalent metal refers to manganese (II) or cobalt (II), and the coordination polymer is [Mn (cpt) 2] n or [Co(cpt)2] n， The two complexes have isostructural three-dimensional structures, [Mn(cpt)2] n and [Co(cpt)2] n With manganese (II) and cobalt (II) as the center, a six-coordinate structure is formed, and a one-dimensional ring chain structure is formed through the coordination of the ligand carboxyl oxygen atom and the connection of the ligand pyridine nitrogen atom. The ring chain structure is further connected by ligand bridges to form a three-dimensional structure.

[0005] In order to solve the above technical problems, the present invention provides a divalent metal coordination polymer, the chemical formula of which is [Mn(cpt)2] n or [Co(cpt)2] n , the [Mn(cpt)2] n The molecular formula is C 56 H 36 MnN6O6, the [Co(cpt)2] n The molecular formula is C 56 H 36 CoN6O6.

[0006] The present invention also provides a method for preparing the above-mentioned divalent metal coordination polymer, comprising the following steps:

[0007] S1. Dissolving 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine and a divalent metal salt in deionized water to obtain a mixed solution, adding a NaOH solution to adjust the pH value of the mixed solution, and then performing a hydrothermal reaction to obtain a reaction product;

[0008] S2. The reaction product obtained in S1 is naturally cooled and crystallized, and then washed, filtered and dried to obtain a divalent metal coordination polymer.

[0009] According to the preparation method of the divalent metal coordination polymer provided by the present invention, the divalent metal salt in S1 is MnCl2·4H2O or CoCl2·6H2O.

[0010] According to the preparation method of the divalent metal coordination polymer provided by the present invention, the molar ratio of 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine to the divalent metal salt in S1 is 0.05-0.1 mmol: 0.1-0.15 mmol.

[0011] According to the preparation method of the divalent metal coordination polymer provided by the present invention, the pH value of the mixed solution is adjusted to 4.7-6.4 in S1.

[0012] According to the preparation method of the divalent metal coordination polymer provided by the present invention, the temperature of the hydrothermal reaction in S1 is 160-180°C, the temperature rising rate is 5-10°C / h, the hydrothermal reaction is carried out in a sealed reactor, and the hydrothermal reaction time is 3-5 days.

[0013] According to the preparation method of the divalent metal coordination polymer provided by the present invention, the drying condition in S2 is: drying in a constant temperature drying oven at a temperature of 60° C. for 3 hours.

[0014] The present invention also provides an application of the divalent metal coordination polymer, which can be used in the field of antibacterial.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) The present invention adopts a one-pot hydrothermal reaction to prepare a divalent metal coordination polymer, the chemical formula of which is [Mn(cpt)2] n or [Co(cpt)2] n , [Mn(cpt)2] n The molecular formula is C 56 H 36 MnN6O6,[Co(cpt)2] n The molecular formula is C 56 H 36 CoN6O6, this preparation method has the advantages of simple process, convenient operation, high yield and good reproducibility.

[0017] (2) [Mn(cpt)2] prepared by the present invention n and [Co(cpt)2] n It has good antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the coordination environment diagram of manganese (II) in manganese (II) coordination polymer 1;

[0019] Figure 2 is the one-dimensional structure diagram of the manganese(II) coordination polymer 1;

[0020] Figure 3 is the two-dimensional structure diagram of the manganese(II) coordination polymer 1;

[0021] Figure 4 is the three-dimensional structure of the manganese(II) coordination polymer 1;

[0022] Figure 5 is the powder X-ray diffraction pattern of manganese (II) coordination polymer 1 and cobalt (II) coordination polymer 4;

[0023] Figure 6 Filter paper diffusion diagram of manganese (II) coordination polymer 1 for Staphylococcus aureus and Pseudomonas aeruginosa;

[0024] Figure 7 Filter paper diffusion diagram of cobalt (II) coordination polymer 4 for Staphylococcus aureus and Pseudomonas aeruginosa. DETAILED DESCRIPTION

[0025] Example 1

[0026] This embodiment provides a divalent metal coordination polymer [Mn(cpt)2] n The preparation method comprises the following steps:

[0027] S1. Dissolving 0.05 mmol of a ligand 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine (Hcpt) and 0.1 mmol of a metal salt MnCl2·4H2O in deionized water to obtain a mixed solution, adding a NaOH solution to adjust the pH value of the mixed solution to 4.7, and then transferring the mixed solution to an autoclave. The temperature in the autoclave was increased to 160° C. at a heating rate of 5° C. / h, and a hydrothermal reaction was carried out for 5 days to obtain a reaction product.

[0028] The structural formula of Hcpt is:

[0029]

[0030] S2. The reaction product obtained in S1 was naturally cooled and crystallized, and then washed with anhydrous ethanol and filtered under reduced pressure to obtain a light pink crystalline powder, which was placed in an oven at a temperature of 60°C for 3 hours for drying to obtain a manganese (II) coordination polymer 1, i.e., [Mn(cpt)2] n , and the yield was 63%.

[0031] Example 2

[0032] This embodiment provides a divalent metal coordination polymer [Co(cpt)2] n The preparation method comprises the following steps:

[0033] S1. Dissolving 0.05 mmol of a ligand 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine (Hcpt) and 0.1 mmol of a metal salt CoCl2·6H2O in deionized water to obtain a mixed solution, adding a NaOH solution to adjust the pH value of the mixed solution to 4.7, and then transferring the mixed solution to an autoclave. The temperature in the autoclave was increased to 160° C. at a heating rate of 5° C. / h, and a hydrothermal reaction was carried out for 5 days to obtain a reaction product.

[0034] S2. The reaction product obtained in S1 is cooled and crystallized naturally, and then washed with anhydrous ethanol and filtered under reduced pressure to obtain a red crystalline powder, which is then placed in an oven at a temperature of 60°C for 3 hours for drying to obtain cobalt (II) coordination polymer 2, i.e., [Co(cpt)2] n , the yield was 43.7%.

[0035] Example 3

[0036] This embodiment provides a divalent metal coordination polymer [Mn(cpt)2] n The preparation method comprises the following steps:

[0037] S1. Dissolving 0.05 mmol of a ligand 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine and 0.15 mmol of a metal salt MnCl2·4H2O in deionized water to obtain a mixed solution, adding a NaOH solution to adjust the pH value of the mixed solution to 5.3, then transferring the mixed solution to an autoclave, heating the temperature in the autoclave to 160° C. at a heating rate of 5° C. / h, and conducting a hydrothermal reaction for 5 days to obtain a reaction product;

[0038] S2. The reaction product obtained in S1 is cooled and crystallized naturally, and then washed with anhydrous ethanol and filtered under reduced pressure to obtain a light pink crystalline powder, which is then placed in an oven at a temperature of 60°C for 3 hours for drying to obtain a manganese (II) coordination polymer 3, i.e., [Mn(cpt)2] n , with a yield of 43.7%.

[0039] Example 4

[0040] This embodiment provides a divalent metal coordination polymer [Co(cpt)2] n The preparation method comprises the following steps:

[0041] S1. Dissolving 0.05 mmol of a ligand 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine and 0.15 mmol of a metal salt CoCl2·6H2O in deionized water to obtain a mixed solution, adding a NaOH solution to adjust the pH value of the mixed solution to 5.3, then transferring the mixed solution to an autoclave, heating the temperature in the autoclave to 160° C. at a heating rate of 5° C. / h, and conducting a hydrothermal reaction for 5 days to obtain a reaction product;

[0042] S2. The reaction product obtained in S1 is cooled and crystallized naturally, and then washed with anhydrous ethanol and filtered under reduced pressure to obtain a red crystalline powder, which is then placed in an oven at a temperature of 60°C for 3 hours for drying to obtain a cobalt (II) coordination polymer 4, i.e., [Co(cpt)2] n , with a yield of 68.2%.

[0043] Example 5

[0044] This embodiment provides a divalent metal coordination polymer [Mn(cpt)2] n The preparation method comprises the following steps:

[0045] S1. Dissolving 0.1 mmol of a ligand 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine and 0.15 mmol of a metal salt MnCl2·4H2O in deionized water to obtain a mixed solution, adding a NaOH solution to adjust the pH value of the mixed solution to 6.4, and then transferring the mixed solution to an autoclave. The temperature in the autoclave was increased to 180° C. at a heating rate of 10° C. / h, and a hydrothermal reaction was carried out for 3 days to obtain a reaction product.

[0046] S2. The reaction product obtained in S1 was naturally cooled and crystallized, and then washed with anhydrous ethanol and filtered under reduced pressure to obtain a light pink crystalline powder, which was placed in an oven at a temperature of 60°C for 3 hours for drying to obtain a manganese (II) coordination polymer 5, namely [Mn(cpt)2] n , with a yield of 45.6%.

[0047] Example 6

[0048] This embodiment provides a divalent metal coordination polymer [Co(cpt)2] n The preparation method comprises the following steps:

[0049] S1. Dissolving 0.1 mmol of a ligand 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine and 0.15 mmol of a metal salt CoCl2·6H2O in deionized water to obtain a mixed solution, adding a NaOH solution to adjust the pH value of the mixed solution to 6.4, and then transferring the mixed solution to an autoclave. The temperature in the autoclave was increased to 180° C. at a heating rate of 10° C. / h, and a hydrothermal reaction was carried out for 3 days to obtain a reaction product.

[0050] S2. The reaction product obtained in S1 is cooled and crystallized naturally, and then washed with anhydrous ethanol and filtered under reduced pressure to obtain a red crystalline powder, which is then placed in an oven at a temperature of 60°C for 3 hours for drying to obtain a cobalt (II) coordination polymer 6, i.e., [Co(cpt)2] n , with a yield of 53.9%.

[0051] Comparative Example 1

[0052] This comparative example provides a method for preparing a manganese (II) coordination polymer, and the specific steps are as follows:

[0053] S1. Dissolving 0.05 mmol of a ligand 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine and 0.1 mmol of a metal salt MnCl2·4H2O in deionized water to obtain a mixed solution, adding a 0.1 mol / L KOH solution to adjust the pH of the mixed solution to 5, then transferring the mixed solution to an autoclave, heating the temperature in the autoclave to 180° C. at a heating rate of 5° C. / h, and conducting a hydrothermal reaction for 5 days to obtain a reaction product;

[0054] S2. After the reaction product obtained in S1 is cooled to room temperature at a rate of 5°C / h, it is naturally cooled and crystallized. Then, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a light red crystalline powder. The powder is placed in an oven at a constant temperature of 60°C for 3 hours to dry to obtain product 1 with a yield of 42%.

[0055] Comparative Example 2

[0056] This comparative example provides a method for preparing a cobalt (II) coordination polymer, and the specific steps are as follows:

[0057] S1. Dissolving 0.05 mmol of a ligand 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine and 0.1 mmol of a metal salt CoCl2·6H2O in deionized water to obtain a mixed solution, adding a 0.1 mol / L KOH solution to adjust the pH of the mixed solution to 5, then transferring the mixed solution to an autoclave, heating the temperature in the autoclave to 180° C. at a heating rate of 5° C. / h, and conducting a hydrothermal reaction for 5 days to obtain a reaction product;

[0058] S2. After the reaction product obtained in S1 is cooled to room temperature at a rate of 5°C / h, it is naturally cooled and crystallized. It is then washed with anhydrous ethanol and filtered under reduced pressure to obtain a red crystalline powder, which is placed in an oven at a constant temperature of 60°C for 3 hours for drying to obtain product 2 with a yield of 37.6%.

[0059] Example 7

[0060] The manganese (II) coordination polymer 1 prepared in Example 1 and the cobalt (II) coordination polymer 4 prepared in Example 4 were further characterized as follows:

[0061] (1) Crystal structure determination of coordination polymers

[0062] The single crystal of the coordination polymer with a clean and smooth surface, no concave surface and no crack was selected and the X-ray diffractometer was used at 293 (2) K using a BRDUKER SMART APEX-Ⅱ CCD X-ray single crystal diffractometer with a graphite monochromator Mo-Kα (wavelength ) rays, with Diffraction data were collected using a scanning method. All data were corrected for empirical absorption, and the crystal structure was solved using a direct method. The anisotropy parameters and all non-hydrogen atomic coordinates were corrected using the least squares method. F2 was refined using the SHELXTL-97 program, and hydrogen atomic coordinates were obtained by theoretical calculations.

[0063] Detailed crystallographic data are shown in Tables 1 and 2, important bond lengths and angles are shown in Tables 3 and 4, and the crystal structure is shown in Figures 1 to 4 .

[0064] Table 1 Main crystallographic data of Mn(II) coordination polymer 1

[0065]

[0066] Table 2 Main crystallographic data of cobalt(II) coordination polymer 4

[0067]

[0068] Where, R1=∑(||Fo|-|Fc||) / ∑|Fo|, wR2=[∑w(Fo 2 -|Fc 2 ) 2 / ∑w(Fo) 2 ] 1 / 2 ;

[0069] Table 3 Important bond lengths of Mn(II) coordination polymer 1 and bond angle (°)

[0070]

[0071]

[0072] Table 4 Important bond lengths of cobalt(II) coordination polymer 4 and bond angle (°)

[0073] Co(1)-O(2) 1.997(2) Co(1)-O(1) 2.022(2) Co(1)-N(4) 2.157(2) Co(1)-O(4) 2.167(2) Co(1)-N(3) 2.187(2) Co(1)-O(5) 2.218(2) O(2)-Co(1)-O(1) 109.72(10) O(2)-Co(1)-N(4) 92.09(10) O(2)-Co(1)-N(3) 88.59(10) O(1)-Co(1)-N(3) 88.83(9) N(4)-Co(1)-N(3) 177.91(9) O(4)-Co(1)-N(3) 85.74(9) O(2)-Co(1)-O(5) 96.37(10) O(1)-Co(1)-O(5) 153.31(10) N(4)-Co(1)-O(5) 91.72(9) O(4)-Co(1)-O(5) 59.89(9) N(3)-Co(1)-O(5) 86.23(9)

[0074] The two complexes are isostructural three-dimensional structures. Manganese (II) coordination polymer 1 and cobalt (II) coordination polymer 4 are centered on manganese (II) and cobalt (II), respectively, to form a hexacoordinate structure. A one-dimensional ring-chain structure is formed through the coordination of the ligand carboxyl oxygen atom and the connection of the ligand pyridine nitrogen atom. The ring-chain structure is further connected by ligand bridges to form a three-dimensional structure.

[0075] (2) Phase purity characterization of manganese (II) coordination polymer 1 and cobalt (II) coordination polymer 4.

[0076] The powders of manganese (II) coordination polymer 1 and cobalt (II) coordination polymer 4 were characterized by XRD using Bruker / D8Advance instrument. The characterization results are shown in Figure 5 , it can be seen that the manganese (II) coordination polymer 1 and the cobalt (II) coordination polymer 4 have reliable phase purity, which provides a guarantee for their antibacterial applications.

[0077] Example 8

[0078] The filter paper diffusion method was used to investigate the antibacterial activity of manganese (II) coordination polymer 1 and cobalt (II) coordination polymer 4 against Staphylococcus aureus and Pseudomonas aeruginosa.

[0079] First, all the materials required for the experiment were placed in a high-temperature sterilizer at 121°C for sterilization. Then, manganese (II) coordination polymer 1, cobalt (II) coordination polymer 4 and ligand (Hcpt) were taken and sterile DMF solution was selected as the solvent to prepare a solution with a concentration of 10 mg / mL.

[0080] Take tryptone, yeast extract powder, sodium chloride and agar, dissolve them in water and pour them into a sterilized culture dish. After cooling, use them as solid culture medium for subsequent antibacterial experiments.

[0081] The cultured bacterial solution was diluted with sterile water to 5×10 5 CFU / mL, evenly spread on the solid culture medium, and add 8 μL of 10 mg / mL manganese (II) coordination polymer 1, cobalt (II) coordination polymer 4 and ligand (Hcpt) solution on a filter paper with a diameter of 6 mm, respectively, with sterile DMF solution and metal salt solution as blank controls.

[0082] The experiments showed that DMF solution and metal salt solution had no antibacterial activity against the two test strains, while manganese (II) coordination polymer 1 and cobalt (II) coordination polymer 4 had good antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus, which were stronger than the ligand.

[0083] This indicates that the binding of ligands to metal ions enhances the antibacterial activity. Figure 6 and 7 shown.

[0084] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A divalent metal coordination polymer, characterized in that The chemical formula of the divalent metal coordination polymer is [Mn(cpt)2] n or [Co(cpt)2] n , the [Mn(cpt)2] n The molecular formula is C 56 H 36 MnN6O6, the [Co(cpt)2] n The molecular formula is C 56 H 36 CoN6O6.

2. A method for preparing a divalent metal coordination polymer as claimed in claim 1, characterized in that: The following steps are involved: S1. Dissolving 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine and a divalent metal salt in deionized water to obtain a mixed solution, adding a NaOH solution to adjust the pH value of the mixed solution, and then performing a hydrothermal reaction to obtain a reaction product; S2. The reaction product obtained in S1 is naturally cooled and crystallized, and then washed, filtered and dried to obtain a divalent metal coordination polymer.

3. The method for preparing a divalent metal coordination polymer according to claim 2, wherein: The divalent metal salt in S1 is MnCl 2. 4H2O or CoCl 2. 6H2O.

4. The method for preparing a divalent metal coordination polymer according to claim 2, wherein: The molar ratio of 4'-(4-(4-carboxyphenoxy)phenyl-4,2':6',4"-terpyridine to the divalent metal salt in S1 is 0.05-0.1 mmol: 0.1-0.15 mmol.

5. The method for preparing a divalent metal coordination polymer according to claim 2, wherein: The pH value of the mixed solution is adjusted to 4.7-6.4 in S1.

6. The method for preparing a divalent metal coordination polymer according to claim 2, wherein: The temperature of the hydrothermal reaction in S1 is 160-180° C., the temperature rising rate is 5-10° C. / h, the hydrothermal reaction is carried out in a sealed reactor, and the hydrothermal reaction time is 3-5 days.

7. The method for preparing a divalent metal coordination polymer according to claim 2, wherein: The drying conditions in S2 are: drying in a constant temperature drying oven at a temperature of 60° C. for 3 h.

8. Use of the divalent metal coordination polymer according to any one of claims 1 to 7, characterized in that: The divalent metal coordination polymer can be applied in the field of antibacterial.

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