Three-dimensional zinc metal organic complex, preparation method and application

Abstract

The application belongs to the technical field of medical materials, and discloses a three-dimensional zinc metal organic complex, a preparation method and application. A primary mixture is obtained by mixing a Py-ETTE ligand, a H2BODCA ligand, zinc chloride hexahydrate, water and acetonitrile; the obtained primary mixture is uniformly mixed by ultrasonic mixing, and is added into a reaction kettle of polytetrafluoroethylene and kept at 150 DEG C; then, automatic cooling is performed to obtain the three-dimensional zinc metal organic complex. The preparation method is simple, the three-dimensional zinc metal organic complex can be obtained by one-step reaction, has high yield and low cost, and is beneficial to industrial production; the three-dimensional zinc metal organic complex prepared by the application keeps structural stability within pH 3-10; the structure of the three-dimensional zinc metal organic complex of the application can keep stable in eight common solvents; the three-dimensional zinc metal organic complex of the application can be recycled and used as a fluorescent probe for detection of NFT and NFZ.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical materials, and in particular relates to a three-dimensional zinc metal organic complex, a preparation method and an application thereof. Background Art

[0002] Bacterial infections are a major health concern for humans (Adv. Healthc. Mater. 2019, 8, 180-1381; Acta Biomater. 2020, 107, 25). Antibiotics have become the primary treatment for bacterial infections due to their low cost and highly effective pharmacokinetic properties (Coord. Chem. Rev. 2021, 435, 213-793; Nano Res. 2022, 15, 64-30). However, their overuse leads to their residual presence in water, soil, plants, and animals, ultimately spreading through ecological cycles (Inorg. Chem. Front. 2021, 8, 1290; J. Hazard. Mater. 2020, 384, 121-498; Inorg. Chem. 2022, 61, 6101). Unfortunately, long-term consumption of these contaminated foods can lead to weakened immunity, genetic defects, allergic reactions, and various cancers. For example, nitrofuran antibiotics (including nitrofurantoin, nitrofurazone, etc.) are a class of broad-spectrum antibiotics, and their abuse has been shown to cause gene mutations and cancer (Inorg.Chem.2020,59,17608). Therefore, new methods for effectively monitoring antibiotics are urgently needed to protect the environment and human health. However, commonly used detection methods such as capillary electrophoresis, high-performance liquid chromatography, ion mobility spectrometry and mass spectrometry are expensive and time-consuming, and even require sophisticated equipment. In contrast, luminescence methods have the advantages of low cost, easy operation, rapid response and good selectivity, and have been used to detect various antibiotics (New J.Chem.2019,43,16706; Talanta 2017,174,660).

[0003] In recent years, metal-organic framework materials (MOFs) have attracted much attention due to their advantages such as easy availability, simple synthesis, and easy functionalization, and have been used as fluorescent sensors for detecting small molecules and ions. However, the existing research on MOFs-based antibiotic fluorescence detection still has shortcomings, such as poor material stability, low response specificity, poor repeatability, and the additional introduction of heavy metal ions, which limit the practicality of the material to a certain extent (Coord. Chem. Rev. 2021, 435, 213793). Therefore, it is of great significance to design and synthesize new MOFs complexes with different topological structures for the specific response of nitrofuran antibiotics.

[0004] The above analysis reveals the following problems and drawbacks of the existing technology: The preparation methods of zinc metal organic complexes are cumbersome, with low yields and high costs, making them unsuitable for industrial production. The zinc metal organic complex structures are also unstable in common solvents, and the sensitivity of existing zinc metal organic complexes as fluorescent probes for detecting NFT and NFZ is low. Summary of the Invention

[0005] To overcome the problems existing in the related art, the embodiments disclosed in the present invention provide a three-dimensional zinc metal organic complex, a preparation method and an application.

[0006] The technical solution is as follows: a three-dimensional zinc metal organic complex, the molecular formula is [Zn(Py-ETTE)(BODCA)]·H2O, the general structural formula is:

[0007]

[0008] In one embodiment, for One of them.

[0009] In one embodiment, the three-dimensional zinc metal organic complex is a three-dimensional framework structure constructed by a mononuclear zinc metal center, a Py-ETTE ligand, a BODCA dianion and free water molecules.

[0010] In one embodiment, the Py-ETTE ligand is one of 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine and 4,4′-thieno[3,2-b]thiophene-3,6-diylbipyridine; BODCA is a divalent anion of bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid (H2BODCA) that has lost two protons; and the Zn in the mononuclear zinc metal center is a positive divalent zinc ion provided by zinc chloride hexahydrate.

[0011] Another object of the present invention is to provide a method for preparing a three-dimensional zinc metal organic complex, comprising:

[0012] Step 1: Py-ETTE ligand, H2BODCA ligand, zinc chloride hexahydrate, water, and acetonitrile are mixed to obtain a primary mixture;

[0013] Step 2: The obtained primary mixture is uniformly mixed by ultrasonic mixing, and then added into a polytetrafluoroethylene reactor and kept at a constant temperature of 135-150° C. for 66-78 hours;

[0014] Step 3: After automatic cooling, a three-dimensional zinc metal organic complex ([Zn(Py-ETTE)(BODCA)]·H2O, referred to as Zn-MOF) is prepared.

[0015] In step 1, the concentration of the Py-ETTE ligand in the solution is 0.003-0.004 mol / L; the concentration of the BODCA ligand is 0.003-0.004 mol / L; and the concentration of the zinc chloride hexahydrate is 0.006-0.007 mol / L.

[0016] In step 1, the molar ratio of Py-ETTE ligand to H2BODCA ligand is 1:0.9-1.1;

[0017] The molar ratio of Py-ETTE ligand to zinc chloride hexahydrate is 1:1.9-2.2;

[0018] The molar ratio of Py-ETTE ligand and water is 1:10 4 ~1.5×10 4 ;

[0019] The molar ratio of water to acetonitrile added to the reaction is 1:0.16-0.18.

[0020] In one embodiment, in step three, the temperature is automatically lowered to 30-50°C.

[0021] Another object of the present invention is to provide an application of a three-dimensional zinc metal organic complex in a fluorescent probe for detecting antibiotic NFT.

[0022] Another object of the present invention is to provide an application of a three-dimensional zinc metal organic complex in a fluorescent probe for detecting the antibiotic NFZ.

[0023] Another object of the present invention is to provide a three-dimensional zinc metal organic complex dispersed in a biocompatible and biodegradable polycaprolactone (PCL) matrix to form a Zn-MOF-loaded PCL film, and to apply the PCL film as a sensor for NFT and NFZ concentration detection.

[0024] Combining all the above technical solutions, the advantages and positive effects of the present invention are as follows:

[0025] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving the problems, this paper closely combines the technical solutions to be protected by the present invention and the results and data during the research and development process, and analyzes in detail and in depth how the technical solutions of the present invention solve the technical problems and some technical effects brought about by solving the problems, which are specifically described as follows:

[0026] Based on the problems existing in the existing technology, the first object of the present invention is to provide a three-dimensional zinc metal organic complex with good luminescent response to nitrofurantoin (abbreviated as NFT in the present invention) and nitrofurazone (abbreviated as NFZ in the present invention), showing good water stability and acid-base stability.

[0027] The second object of the present invention is to provide a method for preparing a three-dimensional zinc metal organic complex, which uses simple and readily available raw materials to synthesize the three-dimensional zinc metal organic complex in one step, is simple to operate, and has low cost.

[0028] The third object of the present invention is to provide an application of a three-dimensional zinc metal organic complex as a sensor for detecting changes in NFT and NFZ concentrations, and such changes can be identified by color changes visible to the naked eye, with high sensitivity and recyclability.

[0029] like Figures 7(a)-7(b) and Figures 8(a)-8(b) As shown in the results, NFT / NFZ can be detected even when the content in the solution is very small, with a detection limit as low as micromolar level.

[0030] Second, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are described in detail as follows:

[0031] The preparation method of the three-dimensional zinc metal organic complex of the present invention is simple, and the complex can be obtained through a one-step reaction, with high yield and low cost, which is conducive to industrial production. The three-dimensional zinc metal organic complex prepared by the present invention maintains structural stability within a pH range of 3-10. The structure of the three-dimensional zinc metal organic complex of the present invention can also remain stable in eight common solvents. As the concentration of the antibiotics NFT and NFZ increases, the blue fluorescence of the three-dimensional zinc metal organic complex of the present invention regularly weakens, showing a color change visible to the naked eye. The complex is simple to operate, highly sensitive, and can be recycled. It can be used as a fluorescent probe for the detection of NFT and NFZ.

[0032] Third, as auxiliary evidence of the present invention, it is also reflected in the expected benefits and commercial value after the technical solution of the present invention is transformed: after the technical solution of the present invention is transformed, low-concentration rapid non-invasive detection of furazolidone and nitrofural can be realized, the operation is simple and can be reused, which greatly reduces the cost, and the Zn-MOF used is small in amount and does not contain heavy metals, which meets environmental protection requirements, has significant economic benefits, and has significant commercial value and ecological value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure;

[0034] Figure 1 This is a flow chart of a method for preparing a 2,5-zinc metal organic complex provided by an embodiment of the present invention;

[0035] Figure 2is a three-dimensional porous structure model effect drawing of the three-dimensional zinc metal organic complex provided by the embodiment of the present application;

[0036] Figure 3 is a powder diffraction diagram of the Zn-MOF soaked in water for different times provided by the embodiment of the present application;

[0037] Figure 4 is a powder diffraction diagram of the Zn-MOF soaked in different solvents provided by the embodiment of the present application;

[0038] Figure 5 is a powder diffraction diagram of the Zn-MOF soaked in different pH aqueous solutions provided by the embodiment of the present application;

[0039] Fig. 6(a) is a fluorescence response condition curve diagram of the Zn-MOF to some antibiotics provided by the embodiment of the present application;

[0040] Fig. 6(b) is a fluorescence response condition columnar diagram of the Zn-MOF to some antibiotics provided by the embodiment of the present application;

[0041] Fig. 7(a) is a fluorescence spectrum diagram of the Zn-MOF to NFT concentration titration provided by the embodiment of the present application;

[0042] Fig. 7(b) is a fluorescence spectrum diagram of the Zn-MOF to NFZ concentration titration provided by the embodiment of the present application;

[0043] Fig. 8(a) is an anti-interference test condition schematic diagram of the Zn-MOF to NFT provided by the embodiment of the present application;

[0044] Fig. 8(b) is an anti-interference test condition schematic diagram of the Zn-MOF to NFZ provided by the embodiment of the present application;

[0045] Fig. 9(a) is a fluorescence intensity change condition schematic diagram of the Zn-MOF to NFT at 410 nm within five cycles provided by the embodiment of the present application;

[0046] Fig. 9(b) is a fluorescence intensity change condition schematic diagram of the Zn-MOF to NFZ at 410 nm within five cycles provided by the embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application are described in detail below with reference to the drawings. In the following description, a large number of specific details are set forth in order to provide a sufficient understanding of the present application. However, the present application can be implemented in many different ways other than the ones described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, so the present application is not limited to the specific implementations disclosed below.

[0048] 1. Explanation of the embodiment:

[0049] The three-dimensional zinc metal organic complex (Zn-MOF) provided in the embodiment of the present invention has the molecular formula [Zn(Py-ETTE)(BODCA)]·H2O and the general structural formula is:

[0050]

[0051] In an embodiment of the present invention, for One of them.

[0052] In an embodiment of the present invention, the three-dimensional zinc metal organic complex is a three-dimensional framework structure constructed by a mononuclear zinc metal center, a Py-ETTE ligand, a BODCA dianion and free water molecules.

[0053] In an embodiment of the present invention, the Py-ETTE ligand is one of 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine and 4,4′-thieno[3,2-b]thiophene-3,6-diylbipyridine; the BODCA ligand is a divalent anion of bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid (H2BODCA) that has lost two protons; and the Zn in the mononuclear zinc metal center is a positive divalent zinc ion provided by zinc chloride hexahydrate.

[0054] like Figure 1 As shown, the present invention provides a method for preparing a three-dimensional zinc metal organic complex, comprising:

[0055] S1, mixing Py-ETTE ligand, H2BODCA ligand, zinc chloride hexahydrate, water, and acetonitrile to obtain a primary mixture;

[0056] S2, mixing the obtained primary mixture by ultrasonication, adding it into a polytetrafluoroethylene reactor and maintaining the temperature at 135-150° C. for 66-78 hours;

[0057] S3, and then automatically cooled to obtain a three-dimensional zinc metal organic complex ([Zn(Py-ETTE)(BODCA)]·H2O, referred to as Zn-MOF).

[0058] Example 1

[0059] The 2,5-zinc metal organic complex provided in an embodiment of the present invention is a three-dimensional framework jointly constructed by 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine (referred to as Py-ETTE) and a divalent anion of bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid that has lost two protons (referred to as BODCA). The structural formula is [Zn(Py-ETTE)(BODCA)]·H2O (referred to as Zn-MOF1), wherein the Py-ETTE ligand represents 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine; the BODCA ligand represents a divalent anion of bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid that has lost two protons; and Zn represents a positive divalent zinc ion.

[0060] The three-dimensional zinc metal organic complex includes a 2,5-zinc metal organic complex;

[0061] The 2,5-zinc metal organic complex contains a mononuclear zinc metal center, a Py-ETTE ligand, a BODCA dianion, and a free water molecule. The structural formula of the 2,5-zinc metal organic complex is:

[0062]

[0063] In an embodiment of the present invention, the preparation method of the 2,5-zinc metal organic complex comprises:

[0064] Step 1, mixing 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine, bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid, zinc chloride hexahydrate, water and acetonitrile to obtain a primary mixture;

[0065] Step 2: Ultrasonicate for 10 seconds to mix the obtained primary mixture evenly, add it into a 15 mL polytetrafluoroethylene reactor and keep the temperature at 135-150°C for 66-78 hours;

[0066] Step 3: The temperature is then automatically lowered to about 30-50° C. to obtain a 2,5-zinc metal organic complex.

[0067] In an embodiment of the present invention, in step 1, the concentration of 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine in the solution is 0.003-0.004 mol / L; the concentration of bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid is 0.003-0.004 mol / L; and the concentration of zinc chloride hexahydrate is 0.006-0.007 mol / L.

[0068] In an embodiment of the present invention, in step 1, the molar ratio of 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine and bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid fed into the reaction is 1:0.9-1.1.

[0069] In an embodiment of the present invention, in step 1, the molar ratio of 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine and zinc chloride hexahydrate (a type of zinc salt) fed into the reaction is 1:1.9-2.2. The crystals obtained at this ratio are purer.

[0070] In the embodiment of the present invention, in step 1, the molar ratio of the Py-ETTE ligand and water added to the reaction is 1:10. 4 ~1.5×10 4 .

[0071] In an embodiment of the present invention, in step 1, the molar ratio of water to acetonitrile added to the reaction is 1:0.16-0.18.

[0072] In the embodiment of the present invention, in step 2, the solution is kept at a constant temperature of 150° C. for 72 hours in order to provide appropriate energy so that the ligand can better form a coordination bond with the zinc ion.

[0073] In the embodiment of the present invention, in step 3, the 2,5-zinc metal organic complex is a yellow block crystal.

[0074] The 2,5-zinc metal organic complex can maintain structural stability in boiling water, common organic solvents and strong acid and strong alkali environments.

[0075] The 2,5-zinc metal organic complex has a maximum emission peak of 410 nm in the solvent of N,N-dimethylacetamide, exhibiting blue fluorescence. As the concentration of the added antibiotics NFT and NFZ increases, the blue fluorescence begins to weaken. When the concentration of NFT and NFZ is 100 μM, the fluorescence quenching efficiency is 96.8% and 97.4%, respectively. The detection limits of NFT and NFZ are 1.36 μM and 1.11 μM, respectively, indicating that the three-dimensional zinc metal organic complex can be used as a fluorescent probe for detecting the antibiotics NFT and NFZ.

[0076] After the fluorescence of the 2,5-zinc metal organic complex undergoes a blue attenuation change, the fluorescence can be restored to the previous intensity after centrifugation and washing. After being recycled for 5 times, it still shows a good detection effect for NFT and NFZ.

[0077] In an embodiment of the present invention, the structural formula of nitrofurantoin (NFT) is:

[0078] The structural formula of nitrofurazone (NFZ) is:

[0079] The structural formula of H2BODCA is:

[0080] The structural formula of Py-ETTE is:

[0081] Example 2

[0082] In an embodiment of the present invention, the preparation method of the 3,6-zinc metal organic complex comprises:

[0083] Step 1, mixing 4,4′-thieno[3,2-b]thiophene-3,6-diylbipyridine, bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid, zinc chloride hexahydrate, water and acetonitrile to obtain a primary mixture;

[0084] Step 2: Ultrasonicate for 10 seconds to mix the obtained primary mixture evenly, add it into a 15 mL polytetrafluoroethylene reactor and keep it at 150 °C for 72 hours;

[0085] Step 3: The temperature is then automatically lowered to about 30° C. to obtain the 3,6-zinc metal organic complex.

[0086] The 3,6-zinc metal organic complex contains a mononuclear zinc metal center, a Py-ETTE ligand, a BODCA divalent anion, and a free water molecule. The structural formula of the 3,6-zinc metal organic complex is:

[0087]

[0088] Among them, the structural formula of Py-ETTE is:

[0089] The 3,6-zinc metal organic complex has the same physicochemical properties as the 2,5-zinc metal organic complex.

[0090] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0091] 2. Application Examples

[0092] Application Examples

[0093] In the practical application of Zn-MOF provided in the embodiments of the present invention, a mixed matrix film was prepared and used for visual sensing of NFT / NFZ.

[0094] Zn-MOF was dispersed in a biocompatible and biodegradable polycaprolactone (PCL) matrix to form a Zn-MOF-loaded PCL film. (The method was to dissolve 0.3g of polycaprolactone (PCL, Mr ≈ 80,000) in 4mL of dichloromethane. Then, 30mg of Zn-MOF powder was added to the solution. The mixture was stirred for 30 minutes to obtain a well-dispersed solution. The solution was then dropped onto a glass plate at room temperature. After the dichloromethane evaporated, a flexible film was obtained. The film was then rinsed with distilled water three times and air-dried for use.)

[0095] The resulting Zn-MOF-PCL film was cut into strips to test its sensing ability for NFT / NFZ. Under 365nm UV light, the strips were completely quenched upon contact with an NFT / NFZ aqueous solution.

[0096] To further evaluate the recycling performance of Zn-MOF-PCL, the Zn-MOF-PCL film strips were immersed in 95% ethanol for 2 minutes and then air-dried. They were then immersed in an NFT / NFZ solution while monitoring their luminescence emission. The emission intensity (410 nm) of the Zn-MOF-PCL remained unchanged after five cycles of sensing experiments, demonstrating the practicality of Zn-MOF-PCL in detecting NFT / NFZ aqueous solutions.

[0097] III. Evidence of the relevant effects of the embodiments:

[0098] Experimental Examples

[0099] The present invention provides a method for preparing a three-dimensional zinc metal organic complex [Zn(Py-ETTE)(BODCA)]·H2O (hereinafter referred to as Zn-MOF), comprising:

[0100] 0.01 mM 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine (0.0029 g, referred to as Py-ETTE in this application), 0.01 mM bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid (0.0020 g, referred to as H2BODCA in this application), and 0.02 mM zinc chloride hexahydrate (0.0049 g) were added to a 15 mL polytetrafluoroethylene reactor, and then 2 mL of water and 1 mL of acetonitrile were added. The mixture was mixed evenly under ultrasonic conditions, placed in an oven at 150°C for constant temperature reaction for 72 hours, and then cooled to 30°C after 15 hours to obtain yellow block crystals of Zn-MOF1 (2,5-zinc metal organic complex) with a yield of 68.2%.

[0101] Exemplarily, 0.01 mM 4,4′-thieno[3,2-b]thiophene-3,6-diylbipyridine (0.0029 g, referred to as Py-ETTE in this application), 0.01 mM bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid (0.0020 g, referred to as H2BODCA in this application), and 0.02 mM zinc chloride hexahydrate (0.0049 g) were added to a 15 mL polytetrafluoroethylene reactor, and then 2 mL of water and 1 mL of acetonitrile were added. The mixture was mixed evenly under ultrasonic conditions, placed in an oven at 150° C. for constant temperature reaction for 72 hours, and then cooled to 30° C. after 15 hours to obtain yellow block crystals of Zn-MOF2 (3,6-zinc metal organic complex) with a yield of 62.3%.

[0102] The resulting crystals were tested using a Bruker Smart-APEXIICCD X-ray single crystal diffractometer. The resulting crystallographic structure refinement data are shown in Table 1 below, and some bond lengths are shown in Tables 2 and 3.

[0103] Table 1: Structural refinement data of Zn-MOF

[0104]

[0105] Table 2: Some bond lengths of Zn-MOF1

[0106] Zn(1)-O(1) 1.935(4) O(1)-C(9) 1.225(7) Zn(1)-N(1) 2.053(4) O(2)-C(9) 1.328(11) S(1)-C(6) 1.739(5) O(3)-C(9) 1.284(12) S(1)-C(8) 1.704(6) O(4)-C(9) 1.292(12)

[0107] Table 3: Some bond lengths of Zn-MOF2

[0108] Zn(1)-O(1) 1.950(6) O(1)-C(17) 1.275(11) Zn(1)-O(3) 1.972(6) O(2)-C(17) 1.223(11) Zn(1)-N(1) 2.022(7) O(3)-C(25) 1.278(11) Zn(1)-N(2) 2.021(7) O(4)-C(25) 1.236(11) S(1)-C(7) 1.722(9) S(1)-C(15) 1.704(9) S(1)-C(8) 1.718(9) S(1)-C(16) 1.731(9)

[0109] For example, Zn-MOF2, like Zn-MOF1, has a specific response to NFT and NFZ, but the ligand Py-ETTE used is arranged differently and the three-dimensional structure formed is different. Py-ETTE can be

[0110] Exemplarily, the three-dimensional zinc metal-organic complex includes a 2,5-zinc metal-organic complex or a 3,6-zinc metal-organic complex, each of which includes a mononuclear zinc metal center, a Py-ETTE ligand, a BODCA dianion, and a water molecule, wherein the BODCA has atomic position disorder. The metal center is in a tetracoordinate environment of [ZnN2O2].

[0111] In the experiment of the present invention, the three-dimensional zinc metal organic complex has the following general formula:

[0112]

[0113] The sorting formula of the ligand Py-ETTE is:

[0114] for

[0115] when for When , the crystal structure of 2,5-zinc metal organic complex is:

[0116]

[0117] when for When , the crystal structure of 3,6-zinc metal organic complex is:

[0118]

[0119] Among them, the three-dimensional zinc metal organic complex is a yellow block, stable in boiling water, and stable in the pH range of 3-10; under 360nm excitation light, the maximum emission wavelength is at 410nm.

[0120] Among them, Py-ETTE and BODCA both adopt bidentate coordination mode, connecting the zinc metal center to form a three-dimensional porous framework, and the free water molecules are inside the pores ( Figure 2 ).

[0121] The phase purity and stability of the prepared Zn-MOF were characterized using a Bruker D8 ADVANCE powder diffractometer. Figure 3 As shown, by comparing the curve obtained from the experiment with the curve obtained from the simulated crystal data, it can be seen that the Zn-MOF prepared by the above method is a pure phase.

[0122] In the present invention, the stability of Zn-MOF in water was tested: In order to verify the stability of the three-dimensional zinc metal organic complex in water, 8 mg of the prepared Zn-MOF was weighed and placed in water, and soaked at room temperature for 72 hours and in boiling water for 24 hours respectively. After being taken out and dried, the test was performed using a Bruker D8 ADVANCE powder diffractometer. Figure 3 As shown, the curve obtained after immersion is still consistent with the original curve of the complex before immersion, indicating that the three-dimensional zinc metal organic complex can maintain good stability in water.

[0123] In the experiment of the present invention, the stability of Zn-MOF in different solvents was tested: In order to verify the stability of the three-dimensional zinc metal organic complex in different solvents, 8 mg of the prepared Zn-MOF was weighed and placed in 8 solvents including dichloromethane, N,N-dimethylacetamide, N,N-dimethylformamide, acetonitrile, acetone, water, dimethyl sulfoxide and methanol, and soaked for 24 hours respectively. After being taken out and dried, the test was carried out using a Bruker D8 ADVANCE powder diffractometer. Figure 4 As shown, the curve obtained after immersion is still consistent with the original curve of the complex before immersion, indicating that the three-dimensional zinc metal organic complex maintains good stability in these solvents.

[0124] In the present invention, the stability of Zn-MOF in acid and alkaline environments was tested: In order to verify the stability of the three-dimensional zinc metal organic complex in acid and alkaline environments, 8 mg of the prepared Zn-MOF was weighed and placed in aqueous solutions with a pH range of 3 to 10 and immersed for 24 hours respectively. After being taken out and dried, the samples were tested using a Bruker D8 ADVANCE powder diffractometer. Figure 5 As shown, the curve obtained after immersion is still consistent with the original curve of the complex before immersion, indicating that the three-dimensional zinc metal organic complex has good stability and can resist the destruction of the crystal structure by external acids and bases, providing a guarantee for its application as an antibiotic fluorescent probe.

[0125] In the experiment of the present invention, Zn-MOF was used to detect antibiotics NFT and NFZ: In order to verify the responsiveness of the three-dimensional zinc metal organic complex to antibiotics NFT and NFZ, 5 mg of the prepared Zn-MOF was accurately weighed and placed in 10 mL of N, N-dimethylacetamide. The Zn-MOF was evenly dispersed in N, N-dimethylacetamide by ultrasonication for 40 minutes to form a suspension with a concentration of 0.5 mg / mL. The fluorescence spectrum of Zn-MOF was titrated in the N, N-dimethylacetamide solution. Figures 6(a)-6(b) It can be seen that the maximum emission wavelength of Zn-MOF is 410nm, and the solution fluorescence is blue. It can be seen intuitively from the bar graph that Zn-MOF has a good fluorescence quenching effect on nitrofuran antibiotics NFT and NFZ. Subsequently, the response ability of Zn-MOF to NFT and NFZ was tested in detail. Figures 7(a)-7(b)As shown in the figure, as the concentration of antibiotics NFT and NFZ increased, the fluorescence emission intensity at 410nm gradually weakened, and the fluorescent color of the solution gradually faded, showing a change visible to the naked eye. According to the results of concentration titration, the detection limits of Zn-MOF for NFT and NFZ were 1.36μM and 1.11μM, respectively, and the quenching efficiency was as high as 96.8% and 97.4%, respectively. Then 9 antibiotics were selected for anti-interference test, including ornidazole (ODZ), metronidazole (MDZ), tetracycline (TC), chloramphenicol (THI), sulfadiazine (SDZ), sulfamethoxazole (SMZI), amoxicillin (AMX), florfenicol (FFC), and cephalexin (CL). Figures 8(a)-9(b) It can be seen that Zn-MOF has good specificity for the detection of NFT and NFZ and is not interfered by other similar species, indicating that Zn-MOF can be used for the detection of NFT and NFZ.

[0126] In the experiment of the present invention, the recyclability of Zn-MOF applied to NFT and NFZ detection: In order to verify the recyclability of Zn-MOF applied to NFT and NFZ detection, 2 mg of the prepared Zn-MOF was accurately weighed and placed in 4 mL of N, N-dimethylacetamide solution. Ultrasonication was performed for 40 minutes to uniformly disperse the Zn-MOF in the N, N-dimethylacetamide solution to prepare a suspension with a concentration of 0.5 mg / mL. The fluorescence spectrum of the suspension in response to NFT and NFZ was collected, and then the Zn-MOF was recovered after centrifugation and washed with clean N, N-dimethylacetamide solution and then used to detect NFT and NFZ. The test was repeated for 5 cycles to obtain 10 fluorescence spectrum curves, which were plotted. Figures 9(a)-9(b) , it can be seen that Zn-MOF can maintain good detection effects on NFT and NFZ within five cycles.

[0127] The above description is only a preferred specific implementation method of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A three-dimensional zinc metal organic complex, characterized in that The three-dimensional zinc metal organic complex has a molecular formula of [Zn(Py-ETTE)(BODCA)]·H2O, and a general structural formula of: for One of them.

2. The three-dimensional zinc metal organic complex according to claim 1, characterized in that In the molecular formula [Zn(Py-ETTE)(BODCA)]·H2O, the Py-ETTE ligand is one of 4,4′-thieno[3,2-b]thiophene-2,5-diylbipyridine and 4,4′-thieno[3,2-b]thiophene-3,6-diylbipyridine; BODCA is a divalent anion of bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid that has lost two protons; the bicyclo[2,2,2]octane-1,4-cyclohexanedicarboxylic acid is abbreviated as H2BODCA; and the Zn in the mononuclear zinc metal center is a positive divalent zinc ion provided by zinc chloride hexahydrate.

3. A method for preparing the three-dimensional zinc metal organic complex according to any one of claims 1 to 2, characterized in that: The preparation method comprises: Step 1: Py-ETTE ligand, H2BODCA ligand, zinc chloride hexahydrate, water, and acetonitrile are mixed to obtain a primary mixture; Step 2: The obtained primary mixture is uniformly mixed by ultrasonic mixing, and then added into a polytetrafluoroethylene reactor and kept at a constant temperature of 135-150° C. for 66-78 hours; Step 3: Then, the temperature is automatically lowered to obtain a three-dimensional zinc metal organic complex.

4. The preparation method according to claim 3, characterized in that In step 1, the concentration of the Py-ETTE ligand in the solution is 0.003-0.004 mol / L; the concentration of the H2BODCA ligand is 0.003-0.004 mol / L; and the concentration of the zinc chloride hexahydrate is 0.006-0.007 mol / L. In step 1, the molar ratio of Py-ETTE ligand to H2BODCA ligand is 1:0.9-1.1; The molar ratio of Py-ETTE ligand to zinc chloride hexahydrate is 1:1.9-2.2; The molar ratio of Py-ETTE ligand and water is 1:10 4 ~1.5×10 4 ; The molar ratio of water to acetonitrile added to the reaction is 1:0.16-0.

18.

5. The preparation method according to claim 3, characterized in that In step three, the temperature is automatically lowered to 30-50°C.

6. Use of the three-dimensional zinc metal organic complex according to any one of claims 1 to 2 as a fluorescent probe for detecting antibiotic NFT.

7. Use of the three-dimensional zinc metal organic complex according to any one of claims 1 to 2 as a fluorescent probe for detecting the antibiotic NFZ.

8. Use of the three-dimensional zinc metal organic complex according to any one of claims 1 to 2 in a sensor, characterized in that: The three-dimensional zinc metal organic complex was dispersed in a polycaprolactone (PCL) matrix to form a Zn-MOF-loaded PCL film, which was then used as a sensor for NFT and NFZ concentration detection.

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