A zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics and preparation method

Abstract

A zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotic markers and a preparation method thereof are disclosed. The method uses 2,6-naphthalene dicarboxylic acid as a ligand and a zinc ion as the metal center to synthesize the zinc-based metal-organic framework material via a solvothermal method. The zinc-based metal-organic framework material prepared by the present invention has a simple preparation method, high purity, and good activity. After drying at room temperature, it can be used for detection without the need for material pretreatment, making it easy to implement. Furthermore, it has the advantages of being fast, simple, selective, highly sensitive, and having a low detection limit in the detection of tetracycline (TET). Therefore, it has great potential application value in the preparation of fluorescent probe solid-state devices and the detection of TET.

Description

Technical Field

[0001] The invention relates to a zinc-based metal-organic framework material with tetracycline antibiotic fluorescence recognition and a preparation method thereof, belonging to the technical field of porous molecular crystal materials. Background Art

[0002] Tetracycline antibiotics are a class of broad-spectrum antibiotics that have made significant contributions to medicine and animal husbandry. Their use is increasing worldwide. However, this increased use of tetracycline (TET) has also led to excessive tetracycline emissions. When tetracycline antibiotics enter ecosystems through biological excretion, their residual concentrations in aquatic and terrestrial environments increase, causing damage to the aquatic ecosystem. The aquatic environment is the starting point of all life. When certain microorganisms in the biome are killed, the inherent ecological balance of the aquatic environment is disrupted. Furthermore, drug-resistant bacteria that survive antibiotic selection become superbugs that are uncontrolled by the environment, posing a threat to human life and safety.

[0003] Although several chemical and biological research techniques have been developed to detect trace tetracyclines instantly and accurately, the analytical detection of tetracycline antibiotics primarily relies on large, expensive instruments such as chromatography-mass spectrometry, which also require skilled operators and time-consuming and complex pretreatment procedures. This undoubtedly significantly increases detection costs and efficiency. Therefore, there is an urgent need to develop new rapid and on-site detection methods and technologies to meet the current demand for rapid on-site monitoring of antibiotics. Fluorescent sensors offer advantages such as ease of operation, short time, high sensitivity, high selectivity, and high cost-effectiveness. In the application of fluorescent sensors, molecular recognition and quantitative analysis are crucial challenges. Therefore, the development of methods that can efficiently and rapidly detect tetracycline antibiotics is essential.

[0004] Metal-organic framework (MOF) fluorescent sensing materials are considered one of the most promising detection methods and are widely used to identify harmful substances such as anions, cations, and small organic molecules (see Qiuzheng Du et al., Coordination Chemistry Reviews, 2020, 404, 213113). Therefore, MOF fluorescent sensing materials could be developed to identify tetracycline. Compared to traditional analytical techniques, MOF-based fluorescent sensing offers advantages such as high precision, high sensitivity, miniaturization, fast response time, and good adaptability. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem of efficient and rapid detection of tetracycline antibiotics and obtain a chemically stable zinc-based metal-organic framework material that responds fluorescently to tetracycline antibiotics. The present invention discloses a zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics and a preparation method.

[0006] The technical solution for implementing the present invention is as follows: a zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics, the chemical formula of the zinc-based metal-organic framework material is: {[Zn(2,6-NBC)H2O]} n ; Where: n is a natural number from 1 to positive infinity; (2,6-NBC) 2- It is obtained by deprotonation of 2,6-naphthalene dicarboxylic acid.

[0007] The zinc-based metal-organic framework material belongs to the monoclinic crystal system, the space group is C2 / c, and the unit cell parameters are: a=22.6644(10)Å, b=6.3248(3)Å, c=7.2896(3)Å, α=90°, β=91.6440(10)°, γ=90°.

[0008] The smallest asymmetric unit of the zinc-based metal-organic framework material consists of a crystallographically independent zinc ion, a 2,6-NBC ligand, and a bound water molecule. The zinc ions form a Zn2(COO)2 secondary structural unit, which is further connected by 2,6-NBC to form a two-dimensional planar structure.

[0009] A method for preparing a zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics. The method uses 2,6-naphthalene dicarboxylic acid as a ligand and zinc ions as a metal center to synthesize the zinc-based metal-organic framework material through a solvent thermal method.

[0010] The method includes the following synthesis steps: dissolving an organic ligand 2,6-NBC in an N,N-dimethylacetamide solvent, dissolving Zn(NO3)26H2O in water to form a mixed liquid, which is then placed in a sealed hydrothermal reactor, heating to 90°C over two hours and maintaining the temperature for three days, then cooling to room temperature over one day, and taking out the solid; and washing the solid multiple times with N,N-dimethylacetamide to obtain white block crystals.

[0011] The concentration of the 2,6-NBC N,N-dimethylformamide solution is 0.01-1 mol / L; the concentration of the Zn(NO3)2·6H2O aqueous solution is 0.01-1 mol / L.

[0012] The zinc-based metal-organic framework material can exist stably in water, methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, acetonitrile, and 1,4-dioxane solvents.

[0013] The Zn-based metal-organic framework material can detect TET through fluorescence changes.

[0014] The fluorescence of the zinc-based metal-organic framework material decreases with the increase of TET concentration, and the fluorescence change curve in low concentration (0-40µM) TET aqueous solution is linearly related to the TET concentration, and its detection limit is 0.272µM -1 The zinc-based metal-organic framework material can be used in the field of detecting TET fluorescent probes.

[0015] The beneficial effects of the present invention are that the zinc-based metal-organic framework material prepared by the present invention has a simple preparation method, high purity, good activity, and can be used for detection after drying at room temperature. No pretreatment of the material is required, and it is easy to implement. At the same time, it has the advantages of being fast, simple, selective, highly sensitive, and having a low detection limit in the detection of antibiotics. Therefore, it has great potential application value in the preparation of fluorescent probe solid-state devices and the detection of tetracycline antibiotics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a coordination environment diagram of the zinc-based metal-organic framework material of the present invention;

[0017] Figure 2 is a unit cell diagram of the zinc-based metal-organic framework material of the present invention;

[0018] Figure 3 is a two-dimensional structural diagram of the zinc-based metal-organic framework material of the present invention;

[0019] Figure 4 The fluorescence spectra of the zinc-based metal-organic framework material of the present invention in different solvents;

[0020] Figure 5 1 is a fluorescence spectrum of the zinc-based metal organic framework material in the embodiment of the present invention to TET and different interfering substance solutions;

[0021] Figure 6 The fluorescence spectra of the zinc-based metal-organic framework material for different concentrations of TET solution in the embodiment of the present invention;

[0022] Figure 7 : is the Stern-Volmer linear plot of TET concentration versus the fluorescence intensity I0 / I of the zinc-based metal-organic framework material in the example ([TET]≤40µM). DETAILED DESCRIPTION

[0023] This embodiment provides a zinc-based metal-organic framework material that can recognize tetracycline antibiotics. The chemical formula of the zinc-based metal-organic framework material is: {[Zn(2,6-NBC)H2O]} n ; Where: n is a natural number from 1 to positive infinity; (2,6-NBC) 2- It is obtained by deprotonation of 2,6-naphthalene dicarboxylic acid.

[0024] The zinc-based metal-organic framework material belongs to the monoclinic crystal system, the space group is C2 / c, and the unit cell parameters are: a=22.6644(10)Å, b=6.3248(3)Å, c=7.2896(3)Å, α=90°, β=91.6440(10)°, γ=90°.

[0025] The minimum asymmetric unit of the zinc-based metal-organic framework material consists of one crystallographically independent zinc ion, one 2,6-NBC ligand, and one bound water molecule.

[0026] Zinc ions form Zn2(COO)2 secondary structural units, which are further connected into a two-dimensional planar structure through 2,6-NBC.

[0027] This embodiment provides a method for preparing a zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics. The zinc-based metal-organic framework material is synthesized by a solvothermal method using 2,6-naphthalene dicarboxylic acid as a ligand and zinc ions as the metal center.

[0028] The method of this embodiment includes the following synthesis steps: dissolving 43.2 mg of the organic ligand 2,6-NBC in 4 mL of N,N-dimethylacetamide solvent; dissolving 29.7 mg of Zn(NO3)2·6H2O in 2 mL of water; then mixing the two solutions and placing them in a sealed hydrothermal reactor. The temperature was raised to 90°C over two hours and maintained at this temperature for three days, then cooled to room temperature over one day, and a light yellow solid was removed. After the solid was removed, the solid was washed three times with N,N-dimethylacetamide and water to obtain white block crystals with a yield of 80% based on metallic zinc.

[0029] The properties of the zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics prepared in this example are characterized as follows:

[0030] (1) Structural determination of a zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics in this embodiment:

[0031] The crystal structure was determined using a Supernova single-crystal X-ray diffractometer, using graphite-monochromatized Mo-Kα radiation (λ = 0.71073 Å) as the incident radiation source. Diffraction points were collected using an ω-φ scanning method. Unit cell parameters were corrected using the least-squares method. The crystal structure was solved directly from the difference Fourier electron density map using the SHELXL-97 method and corrected for Lorentz and polarization effects. All hydrogen atoms were determined by difference Fourier synthesis and ideal position calculations. The exact number of solvent molecules was determined by thermogravimetric and elemental analysis. Detailed crystallographic data are shown in Table 1.

[0032]

[0033] (2) Characterization of the fluorescence properties of the zinc-based metal-organic framework material in this example

[0034] Figure 1 This is a coordination environment diagram of the zinc-based metal-organic framework material of the present invention; in the figure, the minimum asymmetric unit of the zinc-based metal-organic framework material has one crystallographically independent zinc ion, and the minimum asymmetric unit of the zinc-based metal-organic framework material has one crystallographically independent structure: Zn(2,6-NBC), and the zinc ion forms a 5-coordinated [ZnO5] secondary structure unit with four O atoms from the 2,6-NBC ligand and one O atom from the H2O ligand.

[0035] Figure 2 This is a unit cell diagram of the zinc-based metal-organic framework material of the present invention; the smallest asymmetric unit of the zinc-based metal-organic framework material in the diagram contains one crystallographically independent zinc ion, one 2,6-NBC ligand and one bound water molecule.

[0036] The smallest asymmetric unit of zinc-based metal-organic framework materials has a crystallographically independent structure: Zn(2,6-NBC).

[0037] Figure 3 The figure shows the two-dimensional structure of the zinc-based metal-organic framework material of this example, where n is a natural number from 1 to positive infinity, indicating that the material is a polymer. The figure shows a crystallographically independent structure of the zinc-based metal-organic framework's smallest asymmetric unit: Zn(2,6-NBC), which is further connected into a two-dimensional network structure through 2,6-NBC ligands.

[0038] Figure 4In order to invent the fluorescence spectrum of the zinc-based metal-organic framework material in different solvents in this embodiment, the horizontal axis in the figure is the fluorescence wavelength and the vertical axis is the fluorescence intensity. It can be seen from the figure that the zinc-based metal-organic framework material exhibits different fluorescence intensities in different solvents, and the fluorescence intensity of the zinc-based metal-organic framework material in DMF solvent is enhanced.

[0039] Figure 5 This figure shows the detection of TET and different interfering substances by the zinc-based metal-organic framework material in an embodiment of the present invention. The horizontal axis in the figure is the fluorescence wavelength and the vertical axis is the fluorescence intensity. It can be seen from the figure that the addition of TET has a significant quenching effect on the fluorescence intensity of the material.

[0040] Figure 6 The fluorescence spectra of the Zn-MOF material in an embodiment of the present invention in response to different concentrations of TET solutions are plotted on the abscissa, and the ordinate, the fluorescence intensity. The figure shows that as TET is gradually added to the aqueous Zn-MOF material, the fluorescence intensity decreases significantly with increasing TET concentrations, demonstrating that the Zn-MOF material exhibits a strong fluorescence response to TET and can be used as a TET fluorescent probe.

[0041] Figure 7 This is a Stern-Volmer plot of TET concentration versus fluorescence intensity I0 / I of the Zn-MOF material in the examples ([TET] ≤ 40µM). The linear equation is y = 1.0092 + 0.0315 * x. The horizontal axis of the plot is TET concentration in µM, and the vertical axis is fluorescence intensity I0 / I. The plot shows that at low TET concentrations (0-40µM), the fluorescence intensity I0 / I of the Zn-MOF material is linearly related to TET concentration, with a detection limit of 0.272µM. -1 When the TET concentration is high, the fluorescence intensity I0 / I of the zinc-based metal-organic framework material is no longer linearly related to the TET concentration.

Claims

1. A zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics, characterized by: The chemical formula of the zinc-based metal-organic framework material is: {[Zn(2,6-NBC)H2O]} n ; Where: n is a natural number from 1 to positive infinity; (2,6-NBC) 2- It is obtained by deprotonation of 2,6-naphthalene dicarboxylic acid; The zinc-based metal-organic framework material belongs to the monoclinic crystal system, the space group is C2 / c, and the unit cell parameters are: a =22.6644(10)Å, b=6.3248(3)Å, c=7.2896(3)Å, α=90°, β=91.6440(10)°, γ =90°; The smallest asymmetric unit of the zinc-based metal-organic framework material consists of a crystallographically independent zinc ion, a 2,6-NBC ligand and a bound water molecule; the zinc ions form a Zn2(COO)2 secondary structural unit, and the secondary structural unit is further connected into a two-dimensional structure through 2,6-NBC.

2. The zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics according to claim 1, characterized in that: The zinc-based metal-organic framework material can exist stably in water, methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, acetonitrile, and 1,4-dioxane solvents.

3. The zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics according to claim 1, characterized in that: The zinc-based metal-organic framework material is used to detect tetracycline antibiotics: tetracycline, namely TET, through fluorescence changes.

4. The zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics according to claim 3, characterized in that: The fluorescence of the zinc-based metal-organic framework material decreases with increasing TET concentration, and the fluorescence change curve in a low-concentration TET aqueous solution is linearly related to the TET concentration, with a detection limit of 0.272µM. The zinc-based metal-organic framework material can be used in the field of detecting TET fluorescent probes.

5. The zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics according to claim 4, characterized in that: The low concentration of TET is 0-40 μM.

6. The method for preparing a zinc-based metal-organic framework material with fluorescent recognition of tetracycline antibiotics according to claim 1, characterized in that: The method includes the following synthesis steps: dissolving 43.2 mg of an organic ligand 2,6-NBC in 4 mL of an N,N-dimethylacetamide solvent, and dissolving 29.7 mg of Zn(NO3)2•6H2O in 2 mL of water respectively; mixing the two solutions, placing them in a sealed hydrothermal reactor, heating them to 90°C over two hours and keeping the temperature constant for three days, then cooling them to room temperature over one day, and taking out a light yellow solid; after taking out the solid, washing the solid three times with N,N-dimethylacetamide and water to obtain white block crystals, with a yield of 80% calculated based on metallic zinc.

Images