阅读说明：本技术 一种具有锌配合物的多酸晶态分子及其制备方法和应用 (Polyacid crystalline molecule with zinc complex and preparation method and application thereof ) 是由 沙靖全 王宇光 张立庆 于 2020-12-31 设计创作，主要内容包括：本发明涉及多酸晶态分子金属配合物技术领域,具体来说是一种具有锌配合物的多酸晶态分子及其制备方法和应用,本发明选择刚性拓展有机分子1,2-二(4-吡啶基)乙烯为桥连试剂,把生命必须金属锌离子与Keggin型多酸结合在一起,在偏钒酸铵和表面活性剂聚乙二醇400的辅助下成功制备了具有锌配合物的多酸晶态分子,确定了其分子式为[Zn(bpe)(PW-(12)O-(40))]-2bpe·2H-2O。本发明首次采用含Zn配合物修饰的多酸开展类过氧化酶催化氧化的比色研究,并用于生物小分子的检测,研究结果发现锌配合物功能化的多酸晶态分子呈现出很好的类过氧化物酶活性,能够被做为检测生物小分子的新型类过氧化物酶催化剂进行应用。(The invention relates to the technical field of polyacid crystalline molecule metal complexes, in particular to a polyacid crystalline molecule with a zinc complex, a preparation method and application thereof, wherein the polyacid crystalline molecule with the zinc complex is successfully prepared by selecting a rigid expanded organic molecule 1, 2-bis (4-pyridyl) ethylene as a bridging reagent and combining metal zinc ions essential for life with Keggin type polyacid together with the assistance of ammonium metavanadate and a surfactant polyethylene glycol 400, and the molecular formula of the polyacid crystalline molecule is determined to be [ Zn (bpe) (PW 400) 12 O 40 )] 2 bpe·2H 2 And O. The invention adopts polyacid modified by Zn-containing complex to carry out colorimetric research of catalytic oxidation of peroxidase, and uses the polyacid modified by Zn-containing complexIn the detection of biological micromolecules, research results show that zinc complex functionalized polyacid crystalline molecules present good peroxidase-like activity and can be used as a novel peroxidase-like catalyst for detecting the biological micromolecules.)

1. A method for preparing polyacid crystalline molecules with zinc complexes is characterized by comprising the following steps:

s1, adding Zn (NO)₃)₂、H₃PW₁₂O₄₀And NH₄VO₃Dissolving in deionized water, stirring and mixing uniformly at room temperature to obtain a mixed solution, adding a polyethylene glycol 400 solution of 1, 2-bis (4-pyridyl) ethane with the concentration of 32-36mg/mL into the mixed solution, continuously stirring for 25-35min, and adjusting the pH value to 4.0-4.4 to obtain a reaction solution;

wherein Zn (NO)₃)₂、H₃PW₁₂O₄₀、NH₄VO₃The ratio of the amount of the substance to the deionized water was 1: 0.08-0.1: 0.28-0.32: 0.25-0.3;

s2, placing the reaction solution of S1 in a polytetrafluoroethylene kettle, reacting at 165-175 ℃ for 5-6 days, gradually cooling to room temperature to obtain black-red blocky crystals, washing with water, and drying to obtain polyacid crystalline molecules with zinc complexes, wherein the molecular formula of the polyacid crystalline molecules is [ Zn (bpe)) (PW) of which₁₂O₄₀)]₂bpe·2H₂O。

2. The method of claim 1, wherein the reaction solution of S1 is 40-50% of the total volume of the polytetrafluoroethylene core.

3. The polyacid crystalline molecule with a zinc complex prepared according to the preparation method of claim 1.

4. Use of a polyacid crystalline molecule having a zinc complex according to claim 3 in the preparation of a peroxidase-like reagent.

5. Use according to claim 4, wherein the polyacid crystalline molecule is used for the detection of ascorbic acid or H₂O₂And (4) content.

6. Use according to claim 4, wherein H is₂O₂The content detection method comprises the following steps:

step 1, dissolving o-phenylenediamine in NaAc-HAc buffer solution with pH of 4.5-7.5, and then adding [ Zn (bpe) (PW) with concentration of 0.6mg/mL₁₂O₄₀)]₂bpe·2H₂O compound crystals are mixed into suspension, and then H with different concentrations of 1-100 mu mol/L is added₂O₂Oscillating the standard solution for 2-12min under the condition of water bath at 25-50 ℃, measuring the absorbance by using an ultraviolet spectrophotometer, and making an absorbance-concentration standard curve;

and 2, replacing the standard solution with a hydrogen peroxide test sample according to the method in the step 1, measuring the absorbance of the test sample, and then calculating the content value of the test sample according to the absorbance-concentration standard curve.

7. Use according to claim 6, wherein the optimal conditions for the water bath are 35-45 ℃.

8. Use according to claim 6, wherein the NaAc-HAc buffer solution has an optimal pH of 6.0 to 7.5.

9. The use of claim 6, wherein the optimal oscillation time is 6-12 min.

10. The use according to claim 4, wherein the ascorbic acid content is determined as follows:

o-phenylenediamine was dissolved in NaAc-HAc buffer solution at pH 7.0, followed by addition of [ Zn (bpe) (PW) at a concentration of 0.6mg/mL₁₂O₄₀)]₂bpe·2H₂O complex crystals are mixed to form a suspension, and then 100 mu mol/L H is added₂O₂Continuing adding ascorbic acid standard solutions with different concentrations within 1-80 mu mol/L after the solution is dissolved, oscillating for 6min under the condition of water bath at 40 ℃, measuring absorbance by adopting an ultraviolet spectrophotometer, and making an absorbance-concentration standard curve;

and 2, replacing the standard solution with an ascorbic acid test sample according to the method in the step 1, measuring the absorbance of the test sample, and then calculating the content value of the test sample according to the absorbance-concentration standard curve.

Technical Field

The invention relates to the technical field of polyacid crystalline molecule metal complexes, in particular to a polyacid crystalline molecule with a zinc complex, and a preparation method and application thereof.

Background

The content of the biological micromolecules in the human body directly influences the health condition of the human body as a vital part in various metabolic processes and the whole life process of the human body; when their concentration in the body varies abnormally, they cause a series of diseases. In organisms, Dopamine (DA), Ascorbic Acid (AA) and Uric Acid (UA) are a very important bioactive small molecule and play a key role in physiological processes such as blood circulation and metabolism of the central nervous system, the production of a plurality of diseases is closely related to the content of the biological molecules, wherein AA is a vitamin which can protect the organism from being attacked by oxidizing substances and can prevent and treat diseases such as cold, mental disorder and the like; DA is used as a nerve conduction substance, can transmit reaction information and stimulation information of the brain, and directly influences the emotion of people; UA is also involved in metabolic processes in the body; because the three molecules exist in the same environment and the signal peak potentials of the three molecules are close to each other, development of a new detection method, a new test technology and development of a novel biological detection material are urgently needed in many fields such as clinical medicine, pathological analysis, biological research and the like so as to carry out respective targeted detection on the three molecules.

Polyoxometalates (POM) are metal-oxygen cluster compounds, show unique optical, electric, magnetic and surface activity and other properties due to the characteristics of diversified structural features, excellent oxidation-reduction performance and the like, and have a plurality of application prospects in the fields of light, electricity, magnetism, catalysis, sensors and the like. Since the polyacid has good redox characteristics and can transfer or transmit multiple electrons in the process of acting with the biological micromolecules, researchers find that the polyacid has excellent enzyme-like activity in recent years, and the application of the polyacid and derivatives thereof in detecting the biological micromolecules attracts the research interest of vast researchers. Although the polyacid exhibits excellent peroxidase-like activity, the specific surface area is very small (1-10 m)²·g^-1) Has less surface active sites, andthe superstrong solubility of polyacid causes its instability, is extremely difficult to recover after exerting the peroxidase-like activity, is not recyclable, and is liable to cause environmental pollution, so that the solution to this problem is imminent.

Researchers find that the polyacid-based crystalline complexes (POMOFs) have higher stability than simple polyacids, can solve the problem that the polyacids are easy to dissolve, have much higher peroxidase-like activity than the simple polyacids due to the synergistic effect among the composite components, and open up a new path for colorimetric sensing research. It is well known that zinc is essential to the human bodyTrace elementsIt plays an extremely important role in human growth and development, immunity, vitamins and the like. And zinc is present in numerous enzyme systems, such as carbonic anhydrase,Respiratory enzymesLactate dehydrogenase, superoxide dismutase, alkaline phosphatase, DNA, RNA polymerase, and the like, which are essential substances for the synthesis of nucleic acids, proteins, and carbohydrates, and for the utilization of vitamin A; according to literature, POMOFs for modifying polyacid by using Zn-MOFs is rarely reported, and the use of Zn-based POMOFs as an enzyme imitation material has not been reported so far.

Disclosure of Invention

Aiming at the technical defects, the invention aims to provide a polyacid crystalline molecule with a zinc complex, and a preparation method and application thereof.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for preparing a polyacid crystalline molecule with a zinc complex, comprising the steps of:

s1, adding Zn (NO)₃)₂、H₃PW₁₂O₄₀And NH₄VO₃Dissolving in deionized water, stirring at room temperature to obtain a mixed solution, adding polyethylene glycol 400 solution of 1, 2-bis (4-pyridyl) ethane with the concentration of 32-36mg/mL into the mixed solution, and continuously stirringAfter 25-35min, adjusting the pH value to 4.0-4.4 to obtain a reaction solution;

wherein Zn (NO)₃)₂、H₃PW₁₂O₄₀、NH₄VO₃The mass ratio of the deionized water to the deionized water is 1: 0.08-0.1: 0.28-0.32: 0.25-0.3;

s2, placing the reaction solution of S1 in a polytetrafluoroethylene kettle, reacting at 165-175 ℃ for 5-6 days, gradually cooling to room temperature to obtain black-red blocky crystals, washing with water, and drying to obtain polyacid crystalline molecules with zinc complexes, wherein the molecular formula of the polyacid crystalline molecules is [ Zn (bpe)) (PW) of which₁₂O₄₀)]₂bpe·2H₂O。

Preferably, the reaction solution of S1 accounts for 40-50% of the total volume of the polytetrafluoroethylene kettle core.

The invention also protects the polyacid crystalline molecule with the zinc complex prepared by the preparation method.

The invention also protects the application of the polyacid crystalline molecules with the zinc complex in preparing the peroxidase-like reagent.

Preferably, the polyacid crystalline molecule is used for detecting ascorbic acid or H₂O₂And (4) content.

Preferably, H₂O₂The content detection method comprises the following steps:

step 1, dissolving o-phenylenediamine in NaAc-HAc buffer solution with pH of 4.5-7.5, and then adding [ Zn (bpe) (PW) with concentration of 0.6mg/mL₁₂O₄₀)]₂bpe·2H₂O compound crystals are mixed into suspension, and then H with different concentrations of 1-100 mu mol/L is added₂O₂Oscillating the standard solution for 2-12min under the condition of water bath at 25-50 ℃, measuring the absorbance by using an ultraviolet spectrophotometer, and making an absorbance-concentration standard curve;

and 2, replacing the standard solution with a hydrogen peroxide test sample according to the method in the step 1, measuring the absorbance of the test sample, and then calculating the content value of the test sample according to the absorbance-concentration standard curve.

Preferably, the optimal conditions of the water bath are 35-45 ℃.

Preferably, the optimal pH of the NaAc-HAc buffer solution is 6.0 to 7.5.

Preferably, the optimal oscillation time is 6-12 min.

Preferably, the ascorbic acid content detection method is as follows:

o-phenylenediamine was dissolved in NaAc-HAc buffer solution at pH 7.0, followed by addition of [ Zn (bpe) (PW) at a concentration of 0.6mg/mL₁₂O₄₀)]₂bpe·2H₂O complex crystals are mixed to form a suspension, and then 100 mu mol/L H is added₂O₂Continuing adding ascorbic acid standard solutions with different concentrations within 1-80 mu mol/L after the solution is dissolved, oscillating for 6min under the condition of water bath at 40 ℃, measuring absorbance by adopting an ultraviolet spectrophotometer, and making an absorbance-concentration standard curve;

and 2, replacing the standard solution with an ascorbic acid test sample according to the method in the step 1, measuring the absorbance of the test sample, and then calculating the content value of the test sample according to the absorbance-concentration standard curve.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention selects rigid expanded organic molecules1, 2-di (4-pyridyl) ethylene is used as a bridging reagent,the essential metal zinc ions and Keggin type polyacid are combined together, and a novel zinc complex functionalized polyacid compound is successfully prepared by adjusting the acidity, the temperature, the molar ratio of various species and the filling degree of a reaction system with the assistance of ammonium metavanadate and a surfactant PEG 400. The molecular formula is determined to be [ Zn (bpe)) (PW by X-ray single crystal diffraction, elemental analysis, infrared spectrum and the like₁₂O₄₀)]₂bpe·2H₂O, Zn-PW for short₁₂Bpe is 1, 2-bis (4-pyridyl) ethane (bis (4-pyridyl) ethylene)); the purity of the compound and the optimal conditions for synthesis were demonstrated using X-ray powder diffraction aids.

2. The invention adopts the polyacid modified by the Zn-containing complex to develop the colorimetric research of the catalytic oxidation of the peroxidase, and is used for detecting the biomolecular Ascorbic Acid (AA), and the research result shows that: [ Zn (bpe) ((P))W₁₂O₄₀)]₂bpe·2H₂O shows good peroxidase-like activity, can be used as a novel peroxidase-like catalyst for detecting ascorbic acid, and is applied to ascorbic acid detection, and experimental results show that: detection of H₂O₂Has a linear range of 1-100. mu. mol/L, a lowest limit of detection (LOD) of 0.145. mu. mol/L, a linear range of 1-80. mu. mol/L for detecting AA, and a lowest limit of detection (LOD) of 0.126. mu. mol/L.

3. The complex reported in the prior art is based on Ag and Cu, and Zn-based complex is not reported; the reasons may be: when Zn and a ligand form a complex to modify polyacid, the Lewis acid-base mismatching, the high energy of complex formation, the poor stability of the complex and other comprehensive factors cause that at present, no clear explanation is provided; the invention uses ammonium metavanadate as mineralizer, which is beneficial to the crystal formation; the solubility of inorganic salt and an organic linking agent is improved by utilizing the nonionic surfactant PEG400 with hydrophilic and hydrophobic groups, and the growth of crystals is effectively guided through the interaction of crystal faces and the surfactant; according to the invention, Zn-based POMOFs with a special structure is synthesized by a hydrothermal method, and finally, a peroxidase-simulated compound with high catalytic activity, low detection lower limit and wide detection range is obtained through peroxidase-simulated activity test.

4. The preparation method has the creativity that:

(1) the hydrothermal reaction in the prior art usually adopts a 'one-pot' mode, bpe organic molecules are firstly dissolved in PEG400, if the organic molecules are not dissolved in advance, inorganic salts and bpe cannot be contacted and reacted sufficiently, supramolecules are formed in subsequent coordination competition, and target complexes cannot be obtained;

(2) ammonium metavanadate is used as a mineralizer, which is beneficial to crystal crystallization, and the mineralizer NH is not added₄VO₃The target compound cannot be obtained;

(3) function of the surfactant PEG 400: the nonionic surfactant PEG with hydrophilic and hydrophobic groups not only improves the solubility of inorganic salt and an organic linking agent, but also effectively guides the growth of crystals through the interaction of crystal faces and the surfactant, and a target compound cannot be obtained without adding the surfactant PEG 400;

(4) if the reaction liquid accounts for more than 50 percent of the total volume of the polytetrafluoroethylene kettle core, the reaction liquid pressure in the hydrothermal process at the same temperature is reduced, and multiple experiments show that the polyacid modified by the Zn-based complex is very sensitive to the factor;

(5) the results show that: the type of zinc salt is critical, other types of zinc salts, such as Zn (Ac)₂、ZnCl₂、ZnSO₄The target compound was not obtained or the yield was extremely low.

The invention utilizes a hydrothermal synthesis method, uses Zn complex modified polyacid to construct Zn-based POMOFs according to the principle of molecular self-assembly, is used in biosensing detection, summarizes the synthesis rule of Zn-based POMOFs crystal material, systematically studies the action mechanism of the Zn-based POMOFs crystal material in biomolecular detection and biomolecular sensing, and provides a new structural model and a solid theoretical foundation for developing a novel biomolecular sensor.

Drawings

FIG. 1 shows [ Zn (bpe) (PW) obtained in example 1 of the present invention₁₂O₄₀)]₂bpe·2H₂An infrared spectrum of O;

FIG. 2 shows [ Zn (bpe) (PW) obtained in example 1 of the present invention₁₂O₄₀)]₂bpe·2H₂Powder diffractogram of O;

FIG. 3(a) is a graph showing [ Zn (bpe)) (PW obtained in example 1₁₂O₄₀)]₂bpe·2H₂A stick schematic of an asymmetric unit of O, in which all hydrogen atoms and free water molecules have been omitted; (b) FIG. is a diagram of a coordination gallery of bpe organic molecules used in examples 1-3; (c) is Zn-PW₁₂The structure of the coordination mode polyhedron structure of (1); (d) is Zn-PW₁₂A coordinate mode ball-stick diagram of (1);

FIG. 4 (a) is a schematic drawing of a subunit A club consisting of bpe used in examples 1 to 3; (b) (c) and (D) are 1D chain, 2D layer and 3D stacking diagram of the crystal, respectively;

FIG. 5 shows [ Zn (bpe) (PW) obtained in example 1 of the present invention₁₂O₄₀)]₂bpe·2H₂O at different reaction times (a), different pH (b), different temperatures (c) and different catalytic H₂O₂Relative activity plots under dose (d) conditions;

FIG. 6 (a) shows Zn-PW obtained in example 1₁₂Crystals at different concentrations of H₂O₂Ultraviolet-visible spectrum of catalytic OPD in the presence; (b) to detect H₂O₂And a corresponding linear calibration plot; (c) Zn-PW prepared for example 1₁₂The crystal catalyzes the ultraviolet-visible spectrum of OPD in the presence of AA with different concentrations; (d) concentration response curves for detecting AA and corresponding linear calibration graphs; Δ A ═ A₀-A_i(A₀And A_iAbsorbance at 422nm before and after addition of AA at a concentration of i, respectively);

FIG. 7 shows [ Zn (bpe) (PW) obtained in example 1 according to the present invention₁₂O₄₀)]2bpe·2H₂The colorimetric sensor of O detects the selectivity (a) and the interference resistance (b) of AA;

FIG. 8 shows the crystalline state [ Zn (bpe) (PW) obtained in example 1 of the present invention₁₂O₄₀)]₂bpe·2H₂O photo micrograph.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, and it should be understood that the scope of the present invention is not limited to the specific embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. The raw materials used in the invention are not indicated by manufacturers, and are all conventional products which can be obtained by commercial purchase.

Example 1

A method for preparing a polyacid crystalline molecule with a zinc complex, comprising the steps of:

s1, mixing 200mg of Zn (NO)₃)₂300mg of H₃PW₁₂O₄₀And 36mg of NH₄VO₃Dissolving in 5mL deionized water, stirring at room temperature for 30min to obtain a mixed solution with a concentration of 35Adding a polyethylene glycol 400 solution of mg/mL 1, 2-bis (4-pyridyl) ethane into the mixed solution, continuously stirring for 30min, and adjusting the pH to 4.2 by using a 1mol/L HCl solution to obtain a reaction solution;

s2, putting the reaction solution of S1 into polytetrafluoroethylene, putting the polytetrafluoroethylene into a stainless steel high-pressure reaction kettle, reacting at a constant temperature of 170 ℃ for 5 days, cooling to 120 ℃ at a speed of 10 ℃/min, naturally cooling to room temperature to obtain black and red blocky crystals, washing with water, and naturally drying to obtain the polyacid crystalline state molecular material with the zinc complex, wherein the molecular formula of the polyacid crystalline state molecular material is [ Zn (bpe) (PW)₁₂O₄₀)]₂bpe·2H₂O。

Example 2

A method for preparing a polyacid crystalline molecule with a zinc complex, comprising the steps of:

s1, mixing 200mg of Zn (NO)₃)₂243mg of H₃PW₁₂O₄₀And 34mg of NH₄VO₃Dissolving in 4mL of deionized water, stirring at room temperature for 30min to obtain a mixed solution, adding a polyethylene glycol 400 solution of 1, 2-bis (4-pyridyl) ethane with the concentration of 32mg/mL into the mixed solution, continuously stirring for 30min, and adjusting the pH value to 4.4 by using a 1mol/L HCl solution to obtain a reaction solution;

s2, putting the reaction solution of S1 into polytetrafluoroethylene, putting the polytetrafluoroethylene into a stainless steel high-pressure reaction kettle, reacting at 175 ℃ for 5 days at constant temperature, cooling to 120 ℃ at the speed of 10 ℃/min, naturally cooling to room temperature to obtain black and red blocky crystals, washing with water, and drying to obtain the polyacid crystalline state molecular material with the zinc complex, wherein the molecular formula of the polyacid crystalline state molecular material is [ Zn (bpe) (PW)₁₂O₄₀)]₂bpe·2H₂O。

Example 3

A method for preparing a polyacid crystalline molecule with a zinc complex, comprising the steps of:

s1, mixing 200mg of Zn (NO)₃)₂305mg of H₃PW₁₂O₄₀And 40mg of NH₄VO₃Dissolving in 6mL deionized water, stirring at room temperature for 30min to obtain a mixed solution, and adjusting the concentrationAdding a polyethylene glycol 400 solution of 36mg/mL 1, 2-bis (4-pyridyl) ethane into the mixed solution, continuously stirring for 30min, and adjusting the pH to 4.0 by using a 1mol/L HCl solution to obtain a reaction solution;

s2, putting the reaction solution of S1 into polytetrafluoroethylene, putting the polytetrafluoroethylene into a stainless steel high-pressure reaction kettle, reacting at a constant temperature of 165 ℃ for 6 days, cooling to 120 ℃ at a speed of 10 ℃/min, naturally cooling to room temperature to obtain black and red blocky crystals, washing with water, and drying to obtain the polyacid crystalline state molecular material with the zinc complex, wherein the molecular formula of the polyacid crystalline state molecular material is [ Zn (bpe) (PW)₁₂O₄₀)]₂bpe·2H₂O。

Characterization and structural description of polyacid complexes:

the single crystal data of the compound is collected at 293K on a Bruker CCD diffractometer, and Mo-Ka rays are obtainedThe crystal structure is resolved by direct method using SHELXTL-97 program, and by full matrix least square method F²And (6) correcting. All non-hydrogen atoms are corrected for anisotropy. And obtaining the position of a hydrogen atom by adopting a theoretical hydrogenation mode. The X-ray single crystal diffraction crystallographic data are shown in table 1:

crystallographic data and Structure of the Compounds of Table 1

R₁＝∑(||F₀|-|F_c||)/∑|F₀|，ωR₂＝∑ω(|F₀|²-|F_c|²)²/∑ω(|F₀|²)²]^1/2

Two, new compound [ Zn (bpe) (PW)₁₂O₄₀)]₂bpe·2H₂Infrared spectrum of O:

novel complex [ Zn (bpe) (PW)₁₂O₄₀)]₂bpe·2H₂O utilizes Alpha Centaurt FT/IR infrared spectrometer, and the measuring range is 400-^-1(KBr tableting); as shown in FIG. 1, at 1058(s) cm^-1，972(s)cm^-1，897(s)cm^-1，799(s)cm^-1The stretching vibration peak position is a characteristic absorption peak of upsilon (P-O), upsilon (W-Od) and upsilon (W-Ob/c-W) of Keggin polyanion; 1618(s) cm^-1，1575(m)cm^-1，1499(m)cm^-1，1153(m)cm^-1，1187(m)cm^-1The position of the stretching vibration peak is the characteristic absorption peak of 1, 2-di (4-pyridyl) ethylene; indicating that the polyacid and the 1, 2-bis (4-pyridyl) ethylene molecule exist in the newly prepared compound, and the Keggin polyacid is not decomposed.

III, novel compound [ Zn (bpe)) (PW₁₂O₄₀)]₂bpe·2H₂Powder diffraction of O:

reacting [ Zn (bpe)) (PW₁₂O₄₀)]₂bpe·2H₂Grinding the O compound in agate grinding to powder with uniform granularity, uniformly paving the powder on a sample plate, and placing the sample plate in an X-ray powder diffractometer, wherein the scanning speed is 5 DEG/min and is within the range of more than 5 DEG and less than 2 theta and less than 50 DEG; the X-ray powder diffraction result is shown in FIG. 2, and the complex [ Zn (bpe)) (PW₁₂O₄₀)]₂bpe·2H₂The O-simulated powder diffraction data (simulated PXRD patterns obtained in Mercury program version 3.3 by crystalline CIF data) are substantially identical to the experimentally tested data peak positions, with only slight differences in intensity, ensuring that the synthesized composite is phase pure.

IV, complex [ Zn (bpe) (PW)₁₂O₄₀)]₂bpe·2H₂Structural description of O:

as shown in FIG. 3(a), single crystal structural analysis revealed a complex [ Zn (bpe)) (PW₁₂O₄₀)]₂bpe·2H₂O belongs to orthorhombic system, pbcn space group; the single crystal structure test shows that one asymmetric unit is composed of 0.5 [ PW₁₂O₄₀]^3-Anion (abbreviated as PW)₁₂) 1 metallic Zn cation, 1.5 1, 2-bis (4-pyridyl) ethane (bpe for short) and 2 water molecules; there is also a free bpe molecule and a free water molecule; it is noteworthy that one water molecule is associated with Zn²⁺Direct connection, and non-connection between Zn; for the crystal structure to be described more clearly below, free molecules can be omitted; PW (pseudo wire)₁₂The coordination pattern with the metal Zn is shown as c and d in FIG. 3, PW₁₂Is in a three-coordination mode, and Zn is in a six-coordination mode; all Zn-N bond lengthsLength of Zn-O bondAnd Zn-O1W bond lengthAre all within normal values; the valence bond calculation result shows that all W atoms in the compound have a valence of +6, and the result is consistent with the single crystal diffraction result; three bpe ligands are connected into a subunit A with the same chain through metal Zn distortion, the dihedral angle number of pyridine formed by taking Zn as a center is 162.413 degrees, and PW is formed₁₂Neatly sitting on the "chain", thereby making Zn (BPE) PW₁₂As secondary building units, are connected by bridging ligands to form a 1D linear chain.

As shown in FIG. 4, [4, 4' -H ] composed of the straight chain and the Wannwang problem₂bpy][Cu(4，4’-bpy)]₂[HPCuMo₁₁O₃₉]The polyoxomolybdate chains are similar in that the bridging oxygen atom connects two opposite positions in the Keggin unit occupied by zn (i) and w (vi), respectively; in the invention, the subunits A are not connected with each other, and the subunits A are connected by the three-coordinate polyacid to form a simple grid-shaped 2D layer; thus, BPE ligand, polyacid PW₁₂And metal Zn are alternately connected to form a 3D stacking diagram;metal ligand chains are represented in 3D stacking plots along the z-axisThe window of (2).

Fifthly, compound [ Zn (bpe) (PW)₁₂O₄₀)]₂bpe·2H₂O to H₂O₂Detection of ascorbic acid molecules

(1) Study of optimum conditions for molecular detection of Hydrogen peroxide

S1, detection instrument

The molecular detection of Ascorbic Acid (AA) is carried out by adopting an Shimadzu UV-2550 ultraviolet spectrophotometer, and the detection wavelength range is 350-600 nm;

s2, selecting conditions

3mL of NaAc-HAc buffer solution and 2mL of o-phenylenediamine were mixed, and 2mg of [ Zn (bpe)) (PW was added₁₂O₄₀)]₂bpe·2H₂O complex crystal, shaking to obtain suspension, adding 100 μ L diluted H with pipette₂O₂Rapidly shaking to make the mixture fully react, timing and observing color change; the appropriate pH value is found by changing the pH value of the HAc-NaAc buffer solution and measuring the ultraviolet spectrum (peak at 350-600nm and 422 nm) at 6 min;

under a proper pH value, controlling different temperatures in a water bath, carrying out experiments, measuring an ultraviolet spectrum (350-600nm) at the time of 6min, and finding out the optimal temperature;

performing experiments under the conditions of optimal temperature and pH value, and measuring ultraviolet spectrums at 2min, 4min, 6min, 8min, 10min and 12 min;

preparing diluted H with different concentrations₂O₂(1. mu.M, 3. mu.M, 5. mu.M, 10. mu.M, 15. mu.M, 30. mu.M, 50. mu.M, 60. mu.M, 70. mu.M, 80. mu.M, 100. mu.M, 150. mu.M, 250. mu.M, 500. mu.M, 1000. mu.M), carrying out the above experiment to obtain absorbance, drawing a standard curve to obtain a detection range, and carrying out linear regression to obtain a linear equation; the standard deviation S was calculated for 10 experiments in the blank group without crystals₀According to LOD ═ KS₀The detection limit is calculated by/S (n is 10, K is 3; S is the slope of the linear equation).

S3 study of optimum conditions

Like natural peroxidases, their catalytic activity is dependent on reaction time, pH, reaction temperature and amount of crystals used; as shown in fig. 5a, as the time (2min, 4min, 6min, 8min, 10min, 12min) increases, the catalytic activity gradually increases, and finally 6min with higher catalytic activity is selected as the reaction time; as shown in fig. 5b and 5c, the optimal pH (4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5) and temperature (25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃) were 7.0 and 40 ℃, respectively; the effect of different amounts of crystals on peroxidase-like activity varies, [ Zn (bpe)) (PW₁₂O₄₀)]₂bpe·2H₂The catalytic activity of O increases with increasing dosage in the range of 0.1-0.6mg/mL and decreases with increasing dosage in the range of 0.6-0.8mg/mL, so it is preferred experimentally to select the optimum reaction conditions for a reaction time of 6min, a pH of 7.0, a temperature of 40 ℃ and a concentration of the polyacid crystalline molecule of the zinc complex of 0.6 mg/mL.

(2) Detection of ascorbic acid AA

O-phenylenediamine was dissolved in NaAc-HAc buffer solution at pH 7.0, followed by addition of [ Zn (bpe) (PW) at a concentration of 0.6mg/mL₁₂O₄₀)]₂bpe·2H₂O complex crystals are mixed into a suspension, and then 100 mu mol/LH is added₂O₂After the solution is dissolved, continuously adding ascorbic acid standard substances with different concentrations in ascorbic acid (1 mu M, 10 mu M, 30 mu M, 50 mu M, 80 mu M and 100 mu M) with different concentrations, shaking for 6min under the water bath condition of 40 ℃, and then measuring absorbance by using an ultraviolet spectrophotometer to prepare an absorbance-concentration standard curve;

the best experimental conditions have been screened using the above experiments: the catalytic experiments with different AA concentrations were carried out for 6min at pH 7.0, temperature 40 ℃ and dose of the polyacid crystalline molecule of the zinc complex of 0.6mg/mL, the specific method being as follows:

2mL of o-phenylenediamine was dissolved in 3mL of NaAc-HAc buffer solution having a pH of 7.0, and [ Zn (bpe) (PW) was added at a concentration of 0.6mg/mL₁₂O₄₀)]₂bpe·2H₂O complex crystals and mixed into a suspension before additionInto 100. mu. mol/LH₂O₂After the solution is dissolved, continuously adding an ascorbic acid test sample, oscillating for 6min under the condition of water bath at 40 ℃, measuring by using an ultraviolet spectrophotometer, and calculating the content of the ascorbic acid according to the absorbance value and the standard curve.

(2) To H₂O₂And AA test results

Carrying out different H₂O₂And AA concentration;

the results are shown in FIG. 6, which shows that assay H₂O₂The linear range of (A) is 1-100 mu mol/L, the lowest limit of detection (LOD) is 0.145 mu mol/L, the linear range of AA detection is 1-80 mu mol/L, the lowest limit of detection (LOD) is 0.126 mu mol/L, (LOD ═ 3S mol/L)₀/S，S₀Is the standard deviation (s.d.) of the blank, S is the slope of the calibration curve.

Six, [ Zn (bpe)) (PW₁₂O₄₀)]₂bpe·2H₂Selectivity and interference immunity study of O on AA sensing

Since the initial purpose of establishing the polyacid-based AA colorimetric sensor is to expect the polyacid-based AA colorimetric sensor to be used in relevant fields such as clinical diagnosis and the like, and other ions and amino acids exist in a human body and may interfere with the AA colorimetric sensor, the evaluation of the selectivity and the interference resistance of the established colorimetric sensor is particularly important.

As shown in FIG. 7(a), K is selected⁺，Na⁺，Cl^-，Mg²⁺，Ca²⁺Glycine (Gly), glutamic acid (Glu), glutathione (Gsh), alanine (Ala), tyrosine (Tyr), Dopamine (DA) and lysine (Lys) were reacted under the same optimum conditions for 6min and then tested; when these substances were added separately, there was almost no change in absorbance at 422nm, whereas when AA was added, there was a significant quenching of absorbance at 422 nm; as shown in FIG. 7(b), when these ions and amino acids were present together with AA, the absorbance was almost the same as that of AA alone, and it was confirmed that [ Zn (bpe)) (PW₁₂O₄₀)]₂bpe·2H₂The O crystal has excellent selectivity and interference resistance for colorimetric sensing of AA.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.