Pyrimidyl oxadiazolone copper (II) metal organic complex as well as preparation method and application thereof

Abstract

The invention discloses a pyrimidyl oxadiazolone copper (II) metal organic complex and a preparation method and application thereof, the chemical formula of the complex is Cu (PPOO) (Cl2), PPOO is 5-(4-phenyl)-3-(2-pyrimidyl)-1, 3, 4,-oxadiazole-2-ketone, the structural formula of PPOO is # imgabs0 #, the pyrimidyl oxadiazolone copper (II) metal organic complex belongs to a triclinic system, the space group is P-1, 3, 4, 5-oxadiazole-2-ketone, and the structural formula of PPOO is as shown in the specification. The cell parameters are as follows: alpha is equal to 85.606 (10) degrees, beta is equal to 88.862 (10) degrees, and gamma is equal to 74.347 (10) degrees. The preparation method of the pyrimidyl oxadiazolone copper (II) metal organic complex is simple, and the obtained complex can catalytically reduce nitrate radicals, shows excellent material stability, and has relatively strong poison resistance.

Description

Technical Field

[0001] The invention relates to the technical field of electrocatalysis, and in particular to a pyrimidinyl oxadiazolone copper (II) metal organic complex and a preparation method and application thereof. Background Art

[0002] With the acceleration of industrialization, the discharge of large amounts of nitrogen-containing compounds such as industrial wastewater and waste residue has led to a continuous increase in nitrate concentrations in water and soil, causing huge pollution to the environment. - When the residue is high, it will cause serious health problems for humans on the one hand, and disrupt the natural nitrogen cycle on the other hand. For a long time, people have usually used physical and chemical methods, biological reduction methods and photocatalytic technologies to treat contaminated water and soil, but all these technologies have the problem of high operating costs and easy secondary pollution. For this reason, people have proposed the strategy of treating nitrates by electrochemical methods. This is because the electrochemical nitrate reduction method has the advantages of low chemical input, environmental friendliness, and mild operating conditions. In addition, electrochemical denitrification can selectively convert nitrates into ammonia or nitrogen, thereby achieving complete harmless treatment of nitrates.

[0003] Design of active and selective electrode materials for electrochemical reduction of NO3 - In this method, noble metals (Pt, Pd, Ir, Ru), transition metals (Cu, Fe, In, Co, Ni, Ti) and bimetallic (CuPd) alloys can be used as working electrodes. Among them, non-noble metal copper-based electrocatalysts have low cost, excellent electrochemical activity, tunable electronic structure, and good performance on NO3 - It has excellent adsorption properties and other advantages, becoming NO3 - Preferred electro-reduction catalysts.

[0004] Metal-organic complexes have broad application prospects in the field of heterogeneous catalysis and have been used as electrocatalysts in NO3 - Reduction, oxygen evolution, hydrogen evolution and carbon dioxide reduction, etc. At present, the research in this field is still in the exploratory stage, and metal organic complex catalysts with novel structures and excellent performances with different organic ligands need to be continuously designed and developed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a pyrimidinyl oxadiazolone copper (II) metal organic complex capable of reducing nitrate by an electrochemical method.

[0006] The present invention solves the above technical problems through the following technical means:

[0007] A pyrimidinyl oxadiazolone copper (II) metal organic complex, the chemical formula of which is Cu(PPOO)(Cl2), wherein PPOO is 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one, and the structural formula of PPOO is The pyrimidinyl oxadiazolone copper (II) metal organic complex belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α=85.606(10)°, β=88.862(10)°, γ=74.347(10)°.

[0008] Preferably, the pyrimidinyl oxadiazolone copper (II) metal organic complex is prepared by a solvothermal reaction using 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one as an organic ligand, cupric chloride as a metal salt, and acetonitrile as a solvent.

[0009] The pyrimidinyl oxadiazolone copper (II) metal organic complex has the following structural characteristics:

[0010] The central Cu(Ⅱ) adopts a hexacoordinated structure, forming an octahedral geometry with two N atoms and four chloride ions from the same PPOO ligand. PPOO is a bidentate chelating ligand, forming a five-membered ring structure with the central Cu(Ⅱ), and each chlorine atom bridges two adjacent Cu(Ⅱ)s to form a one-dimensional chain. The bond length of Cu(Ⅱ)-N is The bond length of Cu(Ⅱ)-Cl is The bond angle of N-Cu(Ⅱ)-Cl is 84.34(8)°~160.10(8)°, the bond angle of Cl-Cu(Ⅱ)-Cl is 85.49(3)°~174.47(3)°, and the bond angle of Cu(Ⅱ)-Cl-Cu(Ⅱ) is 93.56(3)° and 94.51(3)°.

[0011] Beneficial effects: The pyrimidinyl oxadiazolone copper (II) metal organic complex of the present invention can be used as a catalyst to reduce nitrate by an electrochemical method, and the complex has high thermal stability as a crystalline material.

[0012] Preferably, the preparation method of 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one comprises the following steps:

[0013] S1, acylation reaction of 2-hydrazinopyrimidine with benzoyl chloride to obtain N'-(2-pyrimidinyl)benzoylhydrazide;

[0014] S2. N'-(2-pyrimidinyl)benzohydrazide is reacted with triphosgene to form a ring to obtain the 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one, namely PPOO.

[0015] Preferably, in S1 and S2, the reaction temperature is controlled within the range of -10 to 0°C; the reaction solvent used is a mixture of one or more of dichloromethane, chloroform and carbon tetrachloride; and the reaction time is 2-4h.

[0016] Beneficial effects: Some of the raw materials involved in the method for preparing the compound of the present invention are easily decomposed by protic solvents, and non-protic organic matter must be used as a solvent; when the reaction temperature is above 0°C, the product yield is reduced.

[0017] Preferably, in S1, the molar ratio of 2-hydrazinopyrimidine to benzoyl chloride is 1:1.1-1.2.

[0018] Beneficial effect: The benzoyl chloride involved in the synthesis of this step is easy to decompose, so an excessive amount is used to increase the product yield. However, if the molar ratio is above 1:1.2, a diacylated product will appear, which reduces the yield of the target product and causes separation difficulties.

[0019] Preferably, in S2, the molar ratio of N'-(2-pyrimidinyl)benzoylhydrazide to triphosgene is 1:1.2-1.5. The triphosgene involved in the synthesis of this step is easily decomposed, so an excess amount is used to increase the product yield.

[0020] Preferably, in S1 and S2, triethylamine is further added; the molar ratio of 2-hydrazinopyrimidine, triethylamine and benzoyl chloride in S1 is 1:1.5-4:1.1-1.2; the molar ratio of N'-(2-pyrimidinyl)benzoylhydrazide, triethylamine and triphosgene in S2 is 1:1-4:1.2-1.5.

[0021] Preferably, in S1, the specific process of subjecting 2-hydrazinopyrimidine to an acylation reaction with benzoyl chloride to obtain N'-(2-pyrimidinyl)benzoyl hydrazide comprises the following steps: dissolving 2-hydrazinopyrimidine and triethylamine in a solvent, adding dropwise a solution containing benzoyl chloride at -10 to 0°C under nitrogen protection, and stirring the reaction at -10 to 0°C for 2 to 4 hours after the addition is completed; filtering, washing, and drying after the reaction is completed to obtain the N'-(2-pyrimidinyl)benzoyl hydrazide.

[0022] Preferably, in S2, the specific process of reacting N'-(2-pyrimidinyl)benzohydrazide with triphosgene to obtain the PPOO comprises the following steps: dissolving N'-(2-pyrimidinyl)benzohydrazide and triethylamine in a solvent, adding a solution containing triphosgene dropwise at -10 to 0° C. under nitrogen protection, stirring and reacting at -10 to 0° C. for 2 to 4 hours after the addition is completed, filtering, washing, and drying to obtain the PPOO after the reaction is completed.

[0023] The present invention also provides a method for preparing the pyrimidinyl oxadiazolone copper (II) metal organic complex, comprising the following steps: mixing 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one, cupric chloride and an organic solvent, acetonitrile, to obtain a reaction solution; subjecting the reaction solution to a solvent thermal reaction, cooling the reaction solution to room temperature after the reaction is completed, filtering and washing to obtain the pyrimidinyl oxadiazolone copper (II) metal organic complex.

[0024] Beneficial effect: It is difficult to produce complex crystals when reacting in other solvents.

[0025] Preferably, the molar ratio of 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one and copper chloride is 1:1.

[0026] Preferably, the usage ratio of the 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one and the organic solvent acetonitrile is 0.1 mmol:10-15 mL.

[0027] Preferably, the reaction temperature is 80-120°C.

[0028] Preferably, the reaction time is 3 days.

[0029] Beneficial effects: The present invention adopts a solvent thermal method to prepare pyrimidinyl oxadiazolone copper (II) metal organic complex with a high yield. Experiments show that when the reaction temperature is lower than 80°C, it is difficult to form crystals, and when the reaction temperature is higher than 120°C, the product is easy to carbonize.

[0030] Preferably, the preparation method of the pyrimidinyl oxadiazolone copper (II) metal organic complex comprises the following steps: adding cupric chloride dihydrate and PPOO to an acetonitrile solvent, performing a solvothermal reaction at 80-120°C for 3 days, cooling to room temperature, filtering, and washing to obtain the pyrimidinyl oxadiazolone copper (II) metal organic complex.

[0031] The present invention also provides an application of the pyrimidinyl oxadiazolone copper (II) metal organic complex as a catalyst for electrochemical reactions.

[0032] Preferably, the electrochemical reaction is an electrochemical reduction reaction of nitrate.

[0033] Preferably, the electrochemical reaction is an electrochemical reduction reaction of nitrate in an aqueous solution.

[0034] Preferably, the pyrimidinyl oxadiazolone copper (II) metal organic complex and porous carbon powder are mixed and ground in a mass ratio of 1:1 before application, wherein the inert porous carbon powder serves as a carrier and a conductive agent that enhances the conductivity of the complex.

[0035] Preferably, during the electrochemical reaction, a 1M Na2SO4 aqueous solution is used as the electrolyte.

[0036] Preferably, the application as a catalyst for electrochemical reaction specifically includes the following steps: mixing and grinding the obtained pyrimidinyl oxadiazolone copper (II) metal organic complex with inert porous carbon powder to obtain a mixed catalyst, weighing a certain amount of the mixed catalyst, and evenly dispersing it in a mixed solution of isopropanol, water and perfluorosulfonic acid polymer (Nafion) to obtain a catalyst suspension (ink). Pipette an appropriate amount of ink and evenly apply it on the surface of a glassy carbon electrode, dry it, and use it as the working electrode in a three-electrode system, a graphite rod as a counter electrode, and Ag / AgCl as a reference electrode. In 1MNa2SO4 electrolyte containing and not containing 0.1M KNO3, linear sweep voltammetry (LSV) tests are performed respectively.

[0037] Beneficial effect: When KNO3 was not added, the pyrimidine-based oxadiazolone copper (II) metal organic complex electrode surface only produced a very low reduction current. This result proves that the background current generated by the complex in 1M Na2SO4 is small and does not affect NO3 - After adding KNO3, the pyrimidine-based oxadiazolone copper (II) metal organic complex showed excellent catalytic activity, that is, when the cathode potential was -0.33V (potential compared to the reversible reference electrode (vs.RHE)), the current density on the electrode surface reached 10mA / cm 2 , which is much higher than the background current at this time. With the increase of reaction potential, the activity also increases rapidly. When the test potential is -0.6V (potential compared to the reversible reference electrode (vs.RHE)), the current density reaches 100mA / cm 2 , proving that the complex can electrochemically catalyze NO3 - The reduction reaction has the possibility of practical production application.

[0038] Preferably, the application as a catalyst for electrochemical reaction specifically includes the following steps: mixing and grinding the obtained pyrimidine-based oxadiazolone copper (II) metal organic complex with inert porous carbon powder to obtain a mixed catalyst, weighing a certain amount of the mixed catalyst, and evenly dispersing it in a mixed solution of isopropanol, water and Nafion to obtain a catalyst ink. Pipette an appropriate amount of ink and evenly apply it on the surface of a glassy carbon electrode, dry it, and use it as the working electrode in a three-electrode system, a graphite rod as a counter electrode, and Ag / AgCl as a reference electrode. In a 1M Na2SO4 electrolyte containing and not containing 0.1M KNO3, a constant potential test was performed at -0.4V (potential compared to the reversible reference electrode (vs.RHE)).

[0039] Beneficial effect: In an electrolyte containing only Na2SO4, the pyrimidine-based oxadiazolone copper (II) metal organic complex electrode surface only produces a very low reduction current and does not react with NO3 - The electroreduction test was not affected, thus eliminating the interference of hydrogen evolution reaction and other side reactions; in the mixed electrolyte of Na2SO4 and KNO3, the reduction current density of the pyrimidine-based oxadiazolone copper (II) metal organic complex electrode surface did not decay significantly, and always maintained at 30mA / cm 2 , indicating that the complex electrode material exhibits excellent material stability and has strong anti-poisoning ability.

[0040] The advantages of the present invention are:

[0041] The present invention adopts a solvent thermal method to prepare pyrimidinyl oxadiazolone copper (II) metal organic complex with high yield; as a crystalline material, it has high thermal stability and catalytic ability for the electrochemical reduction reaction of nitrate, and can be used as a catalyst to treat NO3 in water. - .

[0042] The preparation method of the pyrimidinyl oxadiazolone copper (II) metal organic complex of the present invention is simple, and the complex exhibits excellent material stability during catalytic reduction of nitrate and has strong anti-poisoning ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a solid infrared spectrum (KBr pellet) of the 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one compound prepared in Example 1 of the present invention;

[0044] Figure 2 The hydrogen nuclear magnetic resonance spectrum (400 MHZ, deuterated DMSO as solvent, tetramethylsilane as internal standard) of the 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one compound prepared in Example 1 of the present invention;

[0045] Figure 3 The carbon nuclear magnetic resonance spectrum (400 MHZ, deuterated DMSO as solvent, tetramethylsilane as internal standard) of the 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one compound prepared in Example 1 of the present invention;

[0046] Figure 4 This is a crystal asymmetric unit structure diagram of the pyrimidinyl oxadiazolone copper (II) metal organic complex in Example 2 of the present invention;

[0047] Figure 5 is a one-dimensional chain structure diagram of the pyrimidinyl oxadiazolone copper (II) metal organic complex in Example 2 of the present invention;

[0048] Figure 6 This is a thermogravimetric analysis diagram of the pyrimidinyl oxadiazolone copper (II) metal organic complex in Example 2 of the present invention;

[0049] Figure 7 The pyrimidinyl oxadiazolone copper (II) metal organic complex catalyzes NO3 - LSV test diagram and background current test diagram of electroreduction;

[0050] Figure 8 The pyrimidinyl oxadiazolone copper (II) metal organic complex catalyzes NO3 - Stability test and background current test of electroreduction;

[0051] Fig. 9 This is a crystal asymmetric unit structure diagram of the pyrimidinyl oxadiazolone cobalt (II) metal organic complex in Comparative Example 2 of the present invention;

[0052] Fig.10 The pyrimidinyl oxadiazolone cobalt (II) metal organic complex in comparative example 2 of the present invention and the pyrimidinyl oxadiazolone copper (II) metal organic complex in example 2 catalyze NO3 - LSV test diagram of electroreduction;

[0053] Fig.11 The crystal asymmetric unit structure diagram of the pyrimidinyl oxadiazolone silver (I) metal organic complex in Comparative Example 3 of the present invention;

[0054] Fig.12 The pyrimidinyl oxadiazolone silver (I) in comparative example 3 of the present invention and the pyrimidinyl oxadiazolone copper (II) metal organic complex in example 2 catalyze NO3 - LSV test diagram of electroreduction. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0057] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0058] Example 1

[0059] The preparation of organic ligand 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one (PPOO) is as follows:

[0060] (1) Preparation of N'-(2-pyrimidinyl)benzoylhydrazide:

[0061] Benzoyl chloride (1.27 g, 9 mmol) was diluted with 20 mL of dichloromethane (DCM), added to a 50 mL double-necked round-bottom flask equipped with a spherical condenser, and cooled to -5°C with magnetic stirring under nitrogen protection to obtain a DCM solution of benzoyl chloride. Dried 2-hydrazinopyrimidine (0.88 g, 8 mmol) was weighed and dissolved in 20 mL of DCM, triethylamine (2.02 g, 20 mmol) was added, and the DCM solution of benzoyl chloride was added dropwise with a constant pressure dropping funnel under nitrogen protection. After the addition was completed, stirring was continued for two hours, and the temperature of the reaction system was always maintained at -5 to 0°C. After the reaction, the product was filtered under reduced pressure, and the filter cake was washed twice with double-distilled water and dried to obtain 1.08 g of light yellow solid (N'-(2-pyrimidinyl)benzohydrazide) with a melting point of 172.8-172.9° C. and a yield of 63.08% (calculated based on 2-hydrazinopyrimidine).

[0062] (2) Preparation of 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one:

[0063] N'-(2-pyrimidinyl)benzoic acid hydrazide (1.0 g, 4.167 mmol) and 20 mL of DCM were added to a 50 mL double-necked round-bottom flask equipped with a spherical condenser, and the temperature was cooled to -5°C under the protection of nitrogen with magnetic stirring, and triethylamine (1.42 g, 14 mmol) was added, and stirring was continued for half an hour to obtain a mixed solution. Triphosgene (1.60 g, 5.39 mmol) was weighed and dissolved in 10 mL of DCM, and added dropwise to the above mixed solution using a constant pressure dropping funnel. After the addition was completed, the reaction was continued with stirring for two hours, and the temperature of the reaction system was always maintained at -5 to 0°C. After the reaction was completed, the reaction mixture was filtered and the filter cake was retained. The filter cake was washed twice with double-distilled water and dried to obtain 0.81 g of 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one solid with a melting point of 182.6-183.3° C. The yield was 72.26% (calculated based on N'-(2-pyrimidinyl)benzohydrazide).

[0064] Figure 1 , Figure 2 and Figure 3 The infrared spectrum, hydrogen nuclear magnetic resonance spectrum and carbon nuclear magnetic resonance spectrum of 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one of Example 1 are respectively; Figure 1-3 It can be seen that the synthesized substance is the target ligand PPOO.

[0065] Example 2

[0066] A method for preparing a pyrimidinyl oxadiazolone copper (II) metal organic complex comprises the following steps:

[0067] CuCl2·2H2O (17.05 mg, 0.1 mmol), PPOO (24 mg, 0.1 mmol) synthesized in Example 1 and acetonitrile solvent (10 mL) were added to a 25 mL hydrothermal reactor, heated to 90°C, and maintained at this temperature for 3 days. After cooling to room temperature, bright red block crystals were obtained, which were filtered and the filter cake was washed with ether to obtain 22.88 mg of the target complex single crystal. The yield calculated based on PPOO was 61.09%.

[0068] Figure 6 The thermogravimetric analysis diagram of the pyrimidinyl oxadiazolone copper (II) metal organic complex of Example 2 is shown in FIG. Figure 6 It can be seen that the complex is stable at 25-244 °C without mass loss; thermal decomposition begins at 244-297 °C, and the rapid weight loss corresponds to the collapse of the skeleton of the pyrimidinyl oxadiazolone ligand and the coordinated Cl - The dissociation of pyrimidine-based oxadiazolone copper (II) metal organic complex prepared is a material with good thermal stability.

[0069] Example 3

[0070] A method for preparing a pyrimidinyl oxadiazolone copper (II) metal organic complex comprises the following steps:

[0071] CuCl2·2H2O (17.05 mg, 0.1 mmol), PPOO (24 mg, 0.1 mmol) synthesized in Example 1 and acetonitrile solvent (15 mL) were added to a 25 mL hydrothermal reactor, heated to 100°C, and maintained at this temperature for 3 days. After cooling to room temperature, bright red block crystals were obtained, which were filtered and the filter cake was washed with ether to obtain 25.75 mg of the target complex single crystal. The yield calculated based on PPOO was 68.74%.

[0072] Example 4

[0073] A method for preparing a pyrimidinyl oxadiazolone copper (II) metal organic complex comprises the following steps:

[0074] CuCl2·2H2O (17.05 mg, 0.1 mmol), PPOO (24 mg, 0.1 mmol) synthesized in Example 1 and acetonitrile solvent (10 mL) were added to a 25 mL hydrothermal reactor, heated to 120°C, and maintained at this temperature for 3 days. After cooling to room temperature, bright red block crystals were obtained, which were filtered and the filter cake was washed with ether to obtain 12.86 mg of the target complex single crystal. The yield calculated based on PPOO was 34.33%.

[0075] Example 5

[0076] The structure of the crystals of the pyrimidinyl oxadiazolone copper (II) metal organic complex prepared in Example 2 was determined.

[0077] A single crystal of 0.24 mm × 0.22 mm × 0.23 mm was selected and analyzed at 296(2) K on a Bruker Smart APEXII CCD single crystal diffractometer using graphite monochromatized Mo-kα radiation. is the incident radiation, X-ray single crystal diffraction data were collected by scanning, the unit cell parameters were refined by the least squares method, the crystal structure was analyzed by the SHELXL-97 direct method, all non-hydrogen atoms were anisotropically refined by the full matrix least squares method, and the H atom positions were determined by theoretical model calculations. Some parameters for crystal diffraction data collection and structure refinement are shown in Table 1. Figure 4 and Figure 5 They are respectively the crystal asymmetric unit structure diagram and the one-dimensional chain structure diagram of the pyrimidinyl oxadiazolone copper (II) metal organic complex of Example 2, indicating that the prepared substance is a one-dimensional chain complex.

[0078] Table 1 is the crystallographic data of pyrimidinyl oxadiazolone copper (II) metal organic complexes

[0079]

[0080] Example 6

[0081] The pyrimidinyl oxadiazolone copper (II) metal organic complex prepared in Example 2 was used as a catalyst for electrochemical reduction of NO3 - , the specific operations are as follows:

[0082] The obtained pyrimidine-based oxadiazolone copper (II) metal organic complex and inert porous carbon powder were mixed and ground in a mass ratio of 1:1 to obtain a catalyst. 1.0 mg of the above catalyst was weighed and evenly dispersed in 1 ml of a mixed solution of isopropanol, water and Nafion (the volume ratio of isopropanol: water: Nafion was 3:1:0.04) to obtain a catalyst suspension (ink). 0.02 ml of ink was evenly applied on the surface of a glassy carbon electrode with a diameter of 0.3 cm, dried, and used as the working electrode in the three-electrode system, a graphite rod as the counter electrode, and Ag / AgCl as the reference electrode. LSV tests were performed in 1M Na2SO4 electrolyte containing and not containing 0.1M KNO3, and the obtained polarization curves were normalized according to the geometric area of ​​the electrode.

[0083] Figure 7 The pyrimidinyl oxadiazolone copper (II) metal organic complex catalyzes NO3 - The LSV test graph and background current test graph of electroreduction show that when the test potential is -0.6V (potential compared to the reversible reference electrode (vs. RHE)), the current density reaches 100mA / cm 2 , proving that the complex can electrochemically catalyze NO3 - reduction reaction.

[0084] Example 7

[0085] The pyrimidinyl oxadiazolone copper (II) metal organic complex prepared in Example 2 was used as a catalyst for electrochemical reduction of NO3 - The specific operation of the stability test is as follows:

[0086] The obtained pyrimidine-based oxadiazolone copper (II) metal organic complex and inert porous carbon powder were mixed and ground in a mass ratio of 1:1, and a catalyst suspension (ink) was prepared according to the method of Example 6, and was evenly coated on the surface of a glassy carbon electrode and dried. It was used as the working electrode in a three-electrode system, a graphite rod was used as a counter electrode, and Ag / AgCl was used as a reference electrode. The stability test was carried out at -0.4 V (potential compared to the reversible reference electrode (vs. RHE)) in a 1M Na2SO4 electrolyte containing and not containing 0.1M KNO3, and the obtained polarization curve was normalized according to the geometric area of ​​the electrode.

[0087] Figure 8 The pyrimidinyl oxadiazolone copper (II) metal organic complex catalyzes NO3 - The constant potential test diagram of electroreduction shows that the complex acts as NO3 - The electrochemically reduced catalyst exhibits good material stability and has excellent anti-poisoning ability.

[0088] Comparative Example 1

[0089] A Chinese patent application document with publication number CN117903176A and titled "An oxadiazolone copper (I) metal organic complex and its preparation method and application" discloses a copper complex, which is 5-(4-methoxyphenyl)-3-(8-quinolyl)-1,3,4-oxadiazol-2-one cuprous chloride metal complex, and it is only reported to have fluorescent properties.

[0090] Comparative Example 2

[0091] Co(Ⅱ) is a common electrochemical catalyst. For this reason, we used PPOO as an organic ligand to prepare Co(PPOO)(Cl2) complex. The specific preparation method is as follows: CoCl2·6H2O (23.79 mg, 0.1 mmol), PPOO (24 mg, 0.1 mmol) synthesized in Example 1 and acetonitrile solvent (10 mL) were added to a 25 mL hydrothermal reactor, heated to 100 ° C, and maintained at this temperature for 3 days. After cooling to room temperature, bright purple columnar crystals were obtained, filtered, and the filter cake was washed with ether to obtain 15.38 mg of single crystals of the target complex. The yield calculated based on PPOO was 41.56%. The crystal structure was determined according to the method of Example 5. The main crystallographic data are: triclinic system, space group P-1, α=85.606(10)°, β=88.862(10)°, γ=74.347(10)°. Fig. 9 The asymmetric unit diagram of Co(PPOO)(Cl2) is shown in Figure 6. The electrochemical reduction effect of nitrate ion was studied using the complex as a catalyst according to the method of Example 6. Fig.10Two metal organic complexes, copper (II) pyrimidinyl oxadiazolone (as shown in the figure as the Cu complex) and cobalt (II) pyrimidinyl oxadiazolone (as shown in the figure as the Co complex), catalyze NO3 - The LSV test diagram of electroreduction is Fig.10 It can be seen that the Co(PPOO)(Cl2) complex has no ability to electrochemically catalyze the reduction of nitrate.

[0092] Comparative Example 3

[0093] Ag(Ⅰ) is also a common electrochemical catalyst. For this reason, we used PPOO as an organic ligand to prepare Ag(PPOO)(NO3) complex. The specific preparation method is as follows: add AgNO3 (16.99 mg, 0.1 mmol), PPOO (24 mg, 0.1 mmol) synthesized in Example 1 and acetone solvent (10 mL) into a 25 mL hydrothermal reactor, heat to 75 ° C, and maintain the temperature for 3 days. After cooling to room temperature, colorless block crystals are obtained, filtered, and the filter cake is washed with ether to obtain 21.77 mg of single crystals of the target complex. The yield calculated based on PPOO is 53.10%. The crystal structure is determined according to the method of Example 5. The main crystallographic data are: monoclinic system, space group is C2 / c, β=112.161(2)°. Fig.11 The asymmetric unit diagram of Ag(PPOO)(NO3) is shown in Figure 6. The electrochemical reduction effect of nitrate ion was studied by using the complex as a catalyst according to the method of Example 6. Fig.12 Two metal organic complexes, copper (II) pyrimidinyl oxadiazolone (shown as the Cu complex) and silver (I) pyrimidinyl oxadiazolone (shown as the Ag complex), catalyze NO3 - The LSV test diagram of electroreduction is Fig.12 It can be seen that the Ag(PPOO)(NO3) complex has no ability to electrochemically catalyze the reduction of nitrate.

[0094] Comparative Example 4

[0095] CuCl2·2H2O (17.05 mg, 0.1 mmol), PPOO (24 mg, 0.1 mmol) synthesized in Example 1 and methanol solvent (10 mL) were added to a 25 mL hydrothermal reactor, heated to 90°C, and maintained at this temperature for 3 days. After cooling to room temperature, a black charred solid was obtained without crystal formation.

[0096] Comparative Example 5

[0097] The only difference from Example 2 is that acetone, N'N-dimethylformamide and chloroform are used to replace acetonitrile, and no crystals are generated.

[0098] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pyrimidinyl oxadiazolone copper (II) metal organic complex, characterized in that: Its chemical formula is Cu(PPOO)(Cl2), where PPOO is 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one, and the structural formula of PPOO is The pyrimidinyl oxadiazolone copper (II) metal organic complex belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α=85.606(10)°, β=88.862(10)°, γ=74.347(10)°.

2. The pyrimidinyl oxadiazolone copper (II) metal organic complex according to claim 1, characterized in that: The method is prepared by using 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazole-2-one as an organic ligand, copper chloride as a metal salt and acetonitrile as a solvent through a solvothermal reaction.

3. A method for preparing the pyrimidinyl oxadiazolone copper (II) metal organic complex as claimed in claim 1 or 2, characterized in that: The method comprises the following steps: mixing 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one, copper chloride and an organic solvent acetonitrile to obtain a reaction solution; subjecting the reaction solution to a solvent thermal reaction, cooling the reaction solution to room temperature after the reaction is completed, filtering and washing the reaction solution to obtain the pyrimidinyl oxadiazolone copper (II) metal organic complex.

4. The method for preparing the pyrimidinyl oxadiazolone copper (II) metal organic complex according to claim 3, characterized in that: The molar ratio of the 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one and copper chloride is 1:

1.

5. The method for preparing the pyrimidinyl oxadiazolone copper (II) metal organic complex according to claim 3, characterized in that: The usage ratio of the 5-(4-phenyl)-3-(2-pyrimidinyl)-1,3,4-oxadiazol-2-one and the organic solvent acetonitrile is 0.1 mmol:10-15 mL.

6. The method for preparing the pyrimidinyl oxadiazolone copper (II) metal organic complex according to claim 3, characterized in that: The reaction temperature is 80-120°C.

7. The method for preparing the pyrimidinyl oxadiazolone copper (II) metal organic complex according to claim 3, characterized in that: The reaction time is 3 days.

8. Use of the pyrimidinyl oxadiazolone copper (II) metal organic complex as claimed in claim 1 or 2 as a catalyst for electrochemical reactions.

9. Use of the pyrimidinyl oxadiazolone copper (II) metal organic complex as a catalyst for electrochemical reactions according to claim 8, characterized in that: The electrochemical reaction is an electrochemical reduction reaction of nitrate.

10. Use of the pyrimidinyl oxadiazolone copper (II) metal organic complex according to claim 8 or 9 as a catalyst for electrochemical reactions, characterized in that: The pyrimidine-based oxadiazolone copper (II) metal organic complex and porous carbon powder are mixed in a mass ratio of 1:1, ground and then used.

Images