Tri-step tin oxide clusters, their preparation methods, and applications

Abstract

This invention discloses a three-step tin oxide cluster, its preparation method, and its applications, belonging to the field of metal complex technology. The three-step tin oxide cluster is prepared using 4-(1,3-dioxo-1,3-dihydroisoindoline-2-yl)-benzoic acid as a ligand and dimethyltin oxide as a substrate. The preparation method is simple and operates under mild conditions. The three-step tin oxide cluster of this invention can be used as a photocatalyst for the photocatalytic production of H2O2. At a reaction light source of 425 nm, the photocatalytic H2O2 production rate is 7764 μmol·g. ‑1 ·h ‑1 The rate of H2O2 production by photocatalysts is higher than that reported in existing literature; the three-step tin oxide cluster of the present invention also has excellent antibacterial activity.

Description

Technical Field

[0001] This invention relates to the field of metal complex technology, specifically to three-step tin oxide clusters, their preparation methods, and applications. Background Technology

[0002] Hydrogen peroxide (H2O2), as a green oxidant, is widely used in medical disinfection, environmental remediation, and chemical synthesis. Currently, H2O2 is mainly produced industrially via the anthraquinone process, but this method suffers from problems such as complex processes, high energy consumption, and the generation of organic pollutants. Photocatalysis, which directly utilizes light energy to convert O2 and H2O into H2O2, offers advantages in terms of cleanliness and sustainability, and has become a research focus in recent years.

[0003] However, existing photocatalysts for H2O2 production still have significant shortcomings. On the one hand, traditional semiconductor catalysts (such as TiO2 and g-C3N4) have low photogenerated carrier separation efficiency, resulting in generally low H2O2 production rates (most below 5000 μmol h⁻¹). - 1 g -1 On the other hand, the preparation process of some high-efficiency catalysts (such as SO3H-COF) is complex, costly, and has poor stability, making it difficult to meet the needs of large-scale applications. Therefore, it is necessary to develop novel photocatalysts that are simple to prepare, low in cost, and have a high H2O2 production rate to promote the industrialization of H2O2 production by photocatalysis.

[0004] Meanwhile, microbial infections, especially those caused by bacteria and fungi, pose a significant challenge to global public health. With the widespread use and even overuse of antibiotics, multidrug-resistant strains (such as methicillin-resistant Staphylococcus aureus, MRSA) are constantly emerging and spreading, greatly diminishing the efficacy of existing antimicrobial drugs, leading to increased difficulty in treating infections and rising morbidity and mortality.

[0005] Organotin carboxylate compounds, as structurally tunable organometallic hybrids, have shown potential application value in photocatalysis due to their unique electronic structure and coordination diversity. Their rigid ladder-like structure facilitates the separation and transport of photogenerated carriers, while the synergistic effect of tin atoms and carboxylic acid ligands may provide active sites for catalytic reactions. On the other hand, organotin carboxylate compounds have become an important direction for antibacterial agent development due to their broad-spectrum antibacterial activity. Most of the organotin carboxylate compounds reported in the prior art have mononuclear or binuclear structures, which suffer from limited structural diversity, poor stability, and low bioavailability; moreover, some compounds exhibit high toxicity and low selectivity, showing poor inhibitory effects against multidrug-resistant strains. In recent years, "ladder-like" organotin oxide clusters have been predicted to possess certain biological activities due to their high stability and unique spatial configuration resulting from their rigid framework. However, there is currently limited research on ladder-like carboxylate compounds targeting the "dimethyltin" building block, and their effectiveness against multidrug-resistant strains and structure-activity relationships remain unclear, failing to provide effective reference for the development of novel antibacterial agents.

[0006] In summary, existing technologies have gaps in both "highly efficient photocatalytic H2O2 production" and "anti-multidrug-resistant bacteria". There is an urgent need to develop a new material that combines high photocatalytic H2O2 production activity with excellent antibacterial properties and is easy to prepare, so as to solve the technical problems in the above two fields at the same time. Summary of the Invention

[0007] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0008] Another objective of this invention is to provide a three-step tin-oxygen cluster with good crystallinity and easy recrystallization for recovery; it can be used as a photocatalyst for the photocatalytic production of H2O2, achieving a H2O2 production rate of 7764 μmol·g under a 425 nm light source. -1 ·h -1 It has a higher H2O2 production rate than photocatalysts reported in existing literature; it also has excellent antibacterial activity, showing effective inhibition of clinically multidrug-resistant MRSA (ATCC 43300) (minimum inhibitory concentration (MIC) = 32 μg / mL), which is superior to gentamicin and has the potential to overcome existing drug resistance problems.

[0009] Another objective of this invention is to provide a method for preparing three-step tin oxide clusters, which has simple synthesis steps, readily available raw materials, and low synthesis cost.

[0010] Another objective of this invention is to provide the application of a three-step tin oxide cluster as a photocatalyst in the photocatalytic production of H2O2, with a photocatalytic H2O2 production rate higher than that of photocatalysts reported in existing literature.

[0011] Another objective of this invention is to provide the application of three-step tin oxide clusters in the preparation of antibacterial agents.

[0012] To achieve these objectives and other advantages according to the present invention, a three-step tin oxide cluster is provided, having the structure of the following formula (I):

[0013] (I).

[0014] Preferably, the three-step tin-oxygen cluster has a crystal structure with the following crystallographic data: monoclinic system, space group P 21 / n, and crystal parameters as follows: axial length a = 7.5188 (4) Å, b = 39.512 (2) Å, c = 11.3605 (6) Å, and included angle... α =90 o , β =92.122 (2) o , γ =90 o Z=2, V=3372.7 (3) Å 3 .

[0015] The objective of this invention can also be further achieved by a method for preparing three-step tin oxide clusters, which includes: dissolving 4-(1,3-dioxo-1,3-dihydroisoindoline-2-yl)benzoic acid as a ligand and dimethyltin oxide in an organic solvent, stirring and heating under reflux, cooling to room temperature after the reaction, filtering, and allowing the filtrate to stand at room temperature and pressure to obtain three-step tin oxide cluster crystals.

[0016] Preferably, the mixing ratio of 4-(1,3-dioxo-1,3-dihydroisoindoline-2-yl)-benzoic acid, dimethyl tin oxide, and organic solvent is 1 mmol : 1 mmol : 50 mL.

[0017] Preferably, the temperature of the reflux reaction is 90-120°C, and the reaction time is 6-10 h.

[0018] Preferably, the filtrate is allowed to stand at room temperature and pressure for 5-10 days.

[0019] Preferably, the organic solvent is toluene.

[0020] The objective of this invention can be further achieved through the application of a three-step tin oxide cluster as a photocatalyst in the catalytic production of H2O2. At a reaction light source of 425 nm, the photocatalytic production rate of H2O2 is 7764 μmol·g. -1 ·h -1 This is higher than the rate of H2O2 production by photocatalysts reported in existing literature.

[0021] The present invention can also be further realized through the application of three-step tin oxide clusters in the preparation of antibacterial agents.

[0022] The present invention has at least the following beneficial effects:

[0023] The three-step tin oxide cluster of this invention exhibits excellent antibacterial activity and catalytic activity for the photocatalytic production of H2O2. Its preparation method is simple and the synthesis cost is low. The three-step tin oxide cluster of this invention can be used as a photocatalyst for the photocatalytic production of H2O2. At a reaction light source of 425 nm, the photocatalytic H2O2 production rate is 7764 μmol·g. -1 ·h -1 The rate of H2O2 production by the photocatalyst is higher than that reported in existing literature. It showed effective inhibition of clinically multidrug-resistant MRSA (ATCC 43300) (MIC = 32 μg / mL), which is superior to gentamicin, and has the potential to overcome existing drug resistance problems.

[0024] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0025] Figure 1 This is a crystal structure diagram of the three-step tin-oxygen cluster prepared in Example 1 of the present invention;

[0026] Figure 2 IR spectrum of the three-step tin oxide cluster prepared in Example 1 of this invention;

[0027] Figure 3 The 1H NMR spectrum of the three-step tin-oxygen cluster prepared in Example 1 of this invention;

[0028] Figure 4 The carbon NMR spectrum of the three-step tin-oxygen cluster prepared in Example 1 of this invention;

[0029] Figure 5 The nuclear magnetic resonance tin spectrum of the three-step tin-oxygen cluster prepared in Example 1 of this invention;

[0030] Figure 6 The time-bactericidal curve of the three-step tin oxide cluster prepared in Example 1 of this invention against Escherichia coli ATCC25922 strain is shown.

[0031] Figure 7 The time-bacterial curve of the three-step tin oxide cluster prepared in Example 1 of this invention against the drug-resistant strain MRSA (ATCC 43300). Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0033] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not imply the presence or addition of one or more other elements or combinations thereof.

[0034] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0035] Main chemical reagents: 4-(1,3-dioxo-1,3-dihydroisoindololin-2-yl)-benzoic acid (Aladdin Reagents), dimethyltin oxide (Aladdin Reagents), toluene (AR, Aladdin Reagents).

[0036] Example 1

[0037] A three-step tin-oxygen cluster having the structure of the following formula (I):

[0038] (I).

[0039] The specific synthesis steps are as follows:

[0040] Dimethyl tin oxide (1 mmol) and 4-(1,3-dioxo-1,3-dihydroisoindololin-2-yl)benzoic acid ligand (1 mmol, structural formula shown in Formula II below) were placed in a 50 mL Erlenmeyer flask, and 50 mL of toluene was added as solvent. The mixture was heated to 110˚C and stirred under reflux for 8 h. After cooling to room temperature, the mixture was filtered into a clean small beaker under normal pressure. After standing at room temperature and pressure for 7 days, crystals precipitated, which were the three-step tin oxide clusters. The yield was 87%, and the melting point was 226℃.

[0041] (II).

[0042] Elemental analysis was performed using a Perkin-Elmer PE2400 carbon, hydrogen, and nitrogen analyzer. The theoretically calculated value of C was... 72 H 64 O 18 Sn4: C, 49.47%; H, 3.69%; O, 16.47%. Tested values: C, 49.52%; H, 3.66%; O, 16.41%. Infrared spectroscopy analysis (IR (cm²)). -1 ): v (C=O) 1768; v as (COO) 1577; vs (COO) 1302; v (Sn-C) 673; ν (Sn-O)₅₁₅. 1H NMR spectroscopy analysis. 1 H NMR (500 MHz, Chloroform- d , ppm) δ 8.09 (d, J = 7.8 Hz, 8H), 7.89 (dd, J = 5.5, 3.1 Hz, 8H), 7.75 (dd, J = 5.5, 3.0 Hz, 8H), 7.52 (d, J = 8.2 Hz, 8H), 4.93 (s, 8H), 1.11 (s, 24H). Carbon NMR spectroscopy analysis. 13 C NMR (126 MHz, Chloroform- d , ppm) δ 175.81 (4C, COO), 167.94 (8C, C=O), 141.68 (4C, Ar-C), 134.18 (8C, Ar-C), 132.03 (8C, Ar-C), 130.99 (4C, Ar-C), 129.30 (8C, Ar-C), 128.37 (8C, Ar-C), 123.51 (8C, Ar-C), 41.33 (4C, -CH2), 4.76 (8C, -CH3). Nuclear magnetic resonance tin spectrum analysis. 119 Sn NMR (187 MHz, CDCl3, ppm): -178.17, -119.25ppm.

[0043] Among them, the crystal structure of the third-step tin-oxygen cluster is as follows: Figure 1 As shown in Table 1, the single-crystal structure parameters are as follows, and the IR spectrum is as follows. Figure 2 As shown, the 1H NMR spectrum is as follows Figure 3 As shown, the carbon NMR spectrum is as follows: Figure 4 As shown, the tin spectrum is as follows Figure 5 As shown.

[0044] Table 1. Single-crystal structural parameters of the three-step tin-oxygen clusters prepared in Example 1

[0045]

[0046] Example 2

[0047] The three-step tin oxide cluster prepared in Example 1 was used as a photocatalyst for the photocatalytic production of H2O2.

[0048] Experiment on photocatalytic production of H2O2:

[0049] Five mg of the three-step tin oxide cluster prepared in Example 1 was weighed and dispersed in 25 mL of deionized water as a photocatalyst. After sonication for 5 min, the mixture was purged in the dark with O2 for 20 min to dissolve sufficient oxygen. The light source was turned on at 425 nm with a power of 100 W. A constant-temperature water circulation system was used to control the reaction temperature. Every 20 min, 1–2 mL of the reaction solution was taken from the photoreactor and filtered through a 0.22 µm nylon filter. The reaction was carried out for a total of 120 min, yielding 6 samples. 10 μL of each sample was taken and added to 990 μL of ultrapure water (sample concentration diluted 100 times). Then, 0.5 mL each of 0.04 mol / L KI solution and 0.04 mol / L potassium hydrogen phthalate solution were added (sample concentration diluted 2 times again). The reaction was carried out for 30 min. Using ultrapure water as a blank, the absorbance at λ=352 nm was measured, and the H2O2 concentration of the sample was calculated using the H2O2 standard curve.

[0050] Quantitative detection method of H2O2 (KI method):

[0051] To prepare a 0.04 mol / L potassium iodide solution: Take 0.664 g of potassium iodide and dilute it to 100 mL with distilled water.

[0052] To prepare a 0.04 mol / L potassium hydrogen phthalate solution: Take 0.817 g of potassium hydrogen phthalate and dilute it to 100 mL with distilled water.

[0053] The content of H2O2 was determined by potassium iodide titration.

[0054] Potassium hydrogen phthalate is used as a buffer solution in the reaction to maintain the acidic environment of the system.

[0055] 1. Potassium hydrogen phthalate is a weak acid with a pKa value of 4.27. It can be used as a buffer solution to provide a stable weakly acidic buffer environment to maintain the pH stability of the reaction system, so that the reaction can be carried out under relatively stable conditions, which is beneficial to ensuring the accuracy and reproducibility of the reaction.

[0056] 2. Potassium hydrogen phthalate can also inhibit side reactions and prevent the disproportionation reaction of I2.

[0057] Detection principle:

[0058] The quantitative calculation of hydrogen peroxide is based on the following formula:

[0059] 2KI + H₂O₂ + 2H + →I2+2K + +2H2O

[0060] KI is colorless, while I2 solution is colored. The amount of I2 generated can be used to determine the yield of H2O2.

[0061] Plotting the H2O2 standard curve:

[0062] Prepare H₂O₂ solutions of 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, and 0.06 mol / L, respectively. Take 1 mL of each solution and add 0.5 mL of 0.04 mol / L KI solution and 0.04 mol / L potassium hydrogen phthalate solution, respectively. React for 20 min, and collect the absorbance at λ=352 nm (where I₂ has maximum absorption) using a UV-Vis spectrophotometer. Plot the absorbance-concentration standard curve of I₂ using the following formula:

[0063] A = 0.283 + 31.3C

[0064] Take 10 μL of sample, add 990 μL of water (sample concentration diluted 100 times), then add 0.5 mL each of 0.04 mol / L KI solution and 0.04 mol / L potassium hydrogen phthalate solution (sample concentration diluted 2 times again), react for 30 min. The blank sample is 1 mL of ultrapure water + 0.5 mL of 0.04 mol / L KI solution + 0.5 mL of 0.04 mol / L potassium hydrogen phthalate solution. Measure the absorbance at λ=352 nm, substitute into the standard curve, and calculate the concentration of H2O2 in each sample.

[0065] The rate of H2O2 production = (μmol·g) -1 ·h -1 );

[0066] In the formula, C ×10 -3 : Amount of H2O2 in 1 mL of sample (mol);

[0067] 25×10 -3 The total amount of H2O2 in 25 mL of water in the reaction system (mol);

[0068] ×2: Dilute the sample by 2 times after sampling;

[0069] ×100: Dilute the sample 100 times after sampling;

[0070] ×10 6 : Convert the unit to μmol;

[0071] 5×10 -3 Photocatalyst mass (g);

[0072] 1h: Reaction time;

[0073] Experimental results of photocatalytic production of H2O2:

[0074] As shown in Table 2 below.

[0075] Table 2. Results of H2O2 production using the three-step tin oxide cluster prepared in Example 1 as a photocatalyst at a reaction light source of 425 nm.

[0076]

[0077] Calculate based on Table 2 and the formula above:

[0078] The rate of H2O2 production = 7764 μmol·g -1 ·h -1 .

[0079] The three-step tin-oxygen cluster of this invention uses 4-(1,3-dioxo-1,3-dihydroisoindoline-2-yl)-benzoic acid as a ligand to coordinate with tin atoms to form a specific polymer structure. It is easy to synthesize, with low raw material and synthesis cost, and possesses photoelectric properties, making it suitable as a photocatalyst for the photocatalytic production of H2O2. At a reaction light source of 425 nm, the photocatalytic production rate of H2O2 by the three-step tin-oxygen cluster structure is 7764 μmol·g. -1 ·h -1 This rate is higher than the H2O2 production rate reported by photocatalysts in existing literature. The highest reported H2O2 production rate in existing literature is achieved by the SO3H-COF catalyst (Custom-Design of Strong Electron / Proton Extractor on COFs for Efficient Photocatalytic H2O2 Production). Angew. Chem. Int. Ed. 2024, 63 , e202320218).

[0080] Example 3

[0081] Antibacterial properties of the three-step tin oxide cluster prepared in Example 1.

[0082] Determination of minimum inhibitory concentration using the micro-broth dilution method:

[0083] I. Experimental Principle:

[0084] The microbroth dilution method is a quantitative antimicrobial susceptibility testing technique based on liquid culture medium. Its core principle lies in constructing an environment with a continuous concentration gradient of the analyte compound in a 96-well microplate through a series of serial dilutions. After introducing a standardized inoculated bacterial suspension into each well, it is cultured under suitable conditions.

[0085] During cultivation, if the concentration of the compound in the well is insufficient to inhibit microbial growth, bacteria will proliferate, causing the culture medium to become turbid. Conversely, if the compound concentration reaches or exceeds its effective antibacterial concentration, bacterial growth is completely inhibited, and the culture medium remains clear. The minimum inhibitory concentration (MIC) is defined as the lowest drug concentration that can completely inhibit the visible growth of microorganisms after a specified cultivation time. This value is the gold standard for evaluating the in vitro activity of antibacterial substances; the lower the value, the stronger the antibacterial activity of the tested compound.

[0086] II. Experimental Procedure:

[0087] 1. Preparation of reagents and materials:

[0088] Stock solution of the test compound: Accurately weigh 10 mg of the three-step tin oxide cluster prepared in Example 1 of this invention and place it in a vacuum drying oven (60℃, 12 h) to remove pore adsorbents. Disperse it in sterile biological DMSO to a final concentration of 1 mg / mL and sonicate it (40 kHz, 30 min) to ensure uniform suspension.

[0089] Strains and culture medium: Escherichia coli (ATCC 25922), Salmonella (NCTC 5776), Staphylococcus aureus (ATCC 25923) and clinically resistant MRSA methicillin-resistant Staphylococcus aureus (ATCC43300) were selected and inoculated into Mueller-Hinton broth (MHB) and pre-cultured at 37°C in a shaker until the logarithmic growth phase (OD600≈0.5, about 6-12h).

[0090] 2. Establishment of the microdilution method for well plates and procedures for drug sensitivity testing:

[0091] The following procedures were followed for performing a three-step tin oxide cluster gradient dilution and drug sensitivity test in a 96-well plate:

[0092] Three-step stanoxa cluster gradient dilution: In column 1, 200 μL of MHB medium containing the three-step stanoxa cluster sample prepared in Example 1 of this invention was added to each well to make its initial concentration 512 μg / mL. Starting from column 2, the dilution was performed sequentially by 2-fold to obtain three-step stanoxa cluster sample solutions with concentration gradients of 256, 128, 64, 32, 16, 8, 4, 2, and 1 μg / mL. Three replicates were set in each column.

[0093] Control group setup:

[0094] Column 11 is set as the negative control group with "only bacterial culture added". 100 μL of MHB medium and 100 μL of bacterial culture (without three-step tin oxide cluster sample) are added to each well.

[0095] Column 12 is set as a blank control group for bacterial culture with "only the three-step stanoxate cluster sample added". 200 μL of MHB medium (bacteria-free) containing the three-step stanoxate cluster sample is added to each well. At the same time, a parallel experimental group of gentamicin is set in this column, which is operated by the same concentration gradient dilution method as the three-step stanoxate cluster sample, and is used as a positive control.

[0096] Strains layout: The vertical (rows) layouts are arranged with different strains of Escherichia coli, Salmonella, and Staphylococcus aureus. Columns 1-10 of each strain's row are the three-step stanoxane gradient dilution experimental groups, and columns 11-12 are the control groups. Each concentration and the control group are set with 3 replicates to ensure experimental repeatability.

[0097] Inoculation with bacterial culture: Take the pre-cultured bacterial culture and adjust it to 1×10⁻⁶ with MHB. 6 CFU / mL, add 100 μL of bacterial culture to each well (final bacterial count 5 × 10⁻⁶). 5 (CFU / mL).

[0098] 3. Incubation and Result Interpretation:

[0099] Culture conditions: Seal the perforated plate with a sealing film and incubate at 37℃ for 18-24 hours.

[0100] MIC determination: Observe the turbidity of each well, and take the lowest drug concentration that completely inhibits bacterial growth as the MIC value.

[0101] Visual interpretation method: After cultivation, place the 96-well plate on a non-reflective surface and observe the turbidity of each well with the naked eye. The compound concentration corresponding to the lowest drug concentration well that is completely clear and shows no visible bacterial growth compared to the growth control well (obviously turbid) is determined as the MIC value.

[0102] Table 3. MIC values ​​of three-step stannous clusters and gentamicin against four bacterial strains.

[0103]

[0104] Among them, the Sn metal complex (Me3Sn)2NH(CH2)(COO)H2O and Me2SnNH(CH2)(COO)[Sn(Cl)2Me2]2 are tin complexes reported in the literature. S. Hussain et al. / Polyhedron . 117 (2016), 64–72).

[0105] As shown in Table 3, the three-step stanoxane cluster of the present invention has excellent inhibitory effects on all four strains. More importantly, the compound of the present invention also shows effective inhibitory effect on clinically multidrug-resistant MRSA (ATCC 43300) (MIC = 32 μg / mL), which is superior to gentamicin, showing the potential to overcome existing drug resistance problems.

[0106] 4. Validation of antibacterial kinetics and mechanisms:

[0107] Time-sterilization curves: Samples were taken at 0, 2, 4, 6, 8, and 24 h at MIC values ​​of 2×, 1×, and 0.5×, respectively, and after serial dilution, they were spread on MHA agar plates and the viable count (CFU / mL) was calculated.

[0108] Specific procedures: Take sterile centrifuge tubes and prepare three-step tin oxide clusters (2×, 1×, 0.5×MIC) at concentrations of approximately 10. 6 CFU / mL bacterial suspension was prepared, and a blank control group containing only MHB medium and a negative control group containing only bacterial suspension were also set up. Sterile centrifuge tubes were placed in a 37°C incubator, and 100 μL of bacterial suspension was aspirated at time points of 0, 2, 4, 6, 8, and 24 h, respectively, and resuspended in 900 μL of sterile PBS (pH=7.2). The suspension was serially diluted 10-fold (adjusting the number of dilutions according to the results of each group of plating), and then evenly spread on MHA plates. The plates were incubated in a 37°C incubator for 24 h, and colony counts were performed. Time-kill curves were plotted, and three replicate groups were set up in parallel.

[0109] The time-bactericidal curve of E. coli ATCC25922 strain is as follows: Figure 6 As shown, by Figure 6 It can be concluded that the three-step tin oxide cluster of the present invention has a concentration-dependent and potent bactericidal effect against Escherichia coli ATCC25922 strain. At a concentration of 0.5×MIC, the compound exhibits rapid bactericidal effect (a decrease in viable bacterial count of more than 5 log units) in the first 4 hours, but subsequently, E. coli ATCC25922 strain regeneration occurs, and the bacterial count recovers to approximately 10 at 24 hours. 8 The concentration of CFU / mL indicates that while this inhibitory concentration can temporarily control the bacterial population, it cannot completely eliminate it. At a concentration of 1×MIC, the bactericidal effect is more prolonged, effectively inhibiting the growth of *E. coli* strain ATCC25922 for 8 hours. However, varying degrees of *E. coli* strain ATCC25922 regrowth were observed at 24 hours, indicating that this concentration is still insufficient for complete sterilization. Most significantly, at a concentration of 2×MIC, the three-step stanoxane cluster of this invention exhibits thorough and sustained bactericidal activity. Viable bacteria were undetectable at 2-hour sampling (lg(CFU / mL)=0), and this bactericidal effect was maintained throughout the entire 24-hour experimental period, with the number of viable bacteria consistently below the detection limit, proving that this concentration can completely kill the initial bacterial population and effectively prevent its resurgence. In summary, the bactericidal effect of the three-step stanoxane cluster of this invention against *E. coli* shows a clear concentration dependence, with a concentration of 2×MIC achieving complete sterilization, highlighting its strong potential in the preparation of antibacterial agents.

[0110] Time-kill curve for drug-resistant strain MRSA (ATCC 43300) is as follows: Figure 7 As shown, by Figure 7 It can be concluded that the three-step tin oxide cluster of the present invention exhibits a significant concentration-dependent bactericidal effect against the drug-resistant strain MRSA. At a concentration of 0.5 × MIC, although the compound can rapidly reduce the viable bacterial count (by approximately 4 log units within 2 hours), its antibacterial effect is incomplete; the drug-resistant strain MRSA regenerates within 24 hours, and the final bacterial count is maintained at 10. 5 The CFU / mL level indicates that the inhibitory concentration was insufficient for complete eradication. At a concentration of 1×MIC, the three-step stannous cluster exhibited rapid bactericidal activity in the first 2 hours, but resistant strain MRSA subsequently re-emerged, with bacterial counts fluctuating around 10 at 24 hours. 0 -10 2 Between CFU / mL, the concentration showed that while it could continuously inhibit bacterial growth, the sterilization effect was not stable enough. However, at a concentration of 2×MIC, the compound exhibited a strong and long-lasting bactericidal effect; after 2 hours of treatment, the viable bacterial count dropped below the detection limit (lg(CFU / mL)≈0), and this sterilization effect was maintained throughout the entire 24-hour experimental period, with the viable bacterial count at each time point consistently close to the detection limit. The overall results indicate that the three-step stannous oxide cluster of this invention has significant bactericidal activity against drug-resistant MRSA strains, especially achieving complete sterilization at a concentration of 2×MIC. This characteristic has important application value for the clinical eradication of drug-resistant MRSA strains.

[0111] 5. Analysis of Experimental Conclusions

[0112] The three-step stanoxane cluster of this invention exhibits clear broad-spectrum antibacterial activity, inhibiting a variety of representative pathogens, including Gram-negative bacteria (such as Escherichia coli ATCC25922 and Salmonella pullorum NCTC5776) and Gram-positive bacteria (such as Staphylococcus aureus ATCC25923). Although its in vitro inhibitory activity against standard sensitive strains (MIC value 8-16 µg / mL) is slightly inferior to the positive control drug gentamicin (MIC value 1 µg / mL), it shows breakthrough potential in combating multidrug-resistant bacteria. Crucially, gentamicin is completely ineffective against methicillin-resistant Staphylococcus aureus (MRSA, ATCC43300), which is extremely difficult to treat clinically, while the three-step stanoxane cluster of this invention still maintains effective inhibitory activity (MIC value 32 µg / mL). Further comparison reveals that, compared to its activity against susceptible Staphylococcus aureus, the inhibitory activity of this three-step stanoxate cluster against the drug-resistant strain MRSA (ATCC 43300) decreased by only 4-fold; while the activity of gentamicin against methicillin-resistant Staphylococcus aureus (MRSA, ATCC43300) decreased by more than 128-fold compared to its activity against susceptible Staphylococcus aureus. This significant difference in activity stability strongly demonstrates that the antibacterial mechanism of the three-step stanoxate cluster differs from that of existing antibiotics, potentially successfully circumventing the inherent major resistance pathway of methicillin-resistant Staphylococcus aureus (MRSA, ATCC43300), thus showing great promise in addressing the global challenge of antibiotic resistance.

[0113] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Other modifications can be readily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A three-ladder tin oxide cluster characterized by, A structure having the following formula (I): （I）。 2. The three-step tin oxide cluster of claim 1, wherein, The third ladder tin oxygen cluster is a crystal structure, and the crystallographic data is as follows: monoclinic system, space group P21 / n, and the crystal parameters are as follows: axis length a = 7.5188 (4) Å, b = 39.512 (2) Å, c = 11.3605 (6) Å, included angle α = 90 °, β = 92.122 (2) °, γ = 90 °, Z = 2, V = 3372.7 (3) Å 3 .

3. A method of preparing the third ladder tin oxide cluster as claimed in claim 1, characterized by, Comprising: The compound of the following formula (II) is dissolved in an organic solvent with dimethyl tin oxide, stirred and heated to reflux, cooled to room temperature after reaction, filtered, and the filtrate is left to stand at room temperature and normal pressure to obtain the three-ladder tin oxygen cluster crystals; (I). (II).

4. The method of claim 3, wherein the third ladder tin oxide cluster is represented by the formula: ###0001### 3 The mixing ratio of the compound of formula (II), dimethyl tin oxide, and organic solvent is 1 mmol: 1 mmol: 50 mL.

5. The method of claim 3, wherein the third ladder tin oxide cluster is represented by the formula: ###0001### 3 The temperature of the heating reflux reaction is 90-120℃, and the reaction time is 6-10 h.

6. The method of claim 3, wherein the third ladder tin oxide cluster is represented by the formula: ###0002### 3 The standing time of the filtrate at room temperature and normal pressure is 5-10 days.

7. The method of claim 3, wherein the third ladder tin oxide cluster is represented by the formula: ###0001### 3 The organic solvent is toluene.

8. The use of the three-step tin oxide cluster as claimed in claim 1 as a photocatalyst in the catalytic reaction of O2 and H2O to produce H2O2, wherein the photocatalytic production rate of H2O2 is 7764 μmol h -1 g -1 .

9. Use of the three-ladder tin oxygen cluster of claim 1 in the preparation of an agent against Escherichia coli ATCC 25922, Salmonella NCTC5776, Staphylococcus aureus ATCC 25923, and clinically drug-resistant strain MRSA methicillin-resistant Staphylococcus aureus ATCC43300.

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