A Cu II Coordination polymers, their preparation methods, and their applications as urease inhibitors

Abstract

The application discloses a Cu II Coordination polymer, preparation method thereof and application of the coordination polymer as urease inhibitor. The technical scheme is as follows: 1,4-butanediamine is used as raw material to synthesize N,N'-bis(3-pyridine carboxamide)-1,4-butane, then the N,N'-bis(3-pyridine carboxamide)-1,4-butane is used as a ligand to construct a novel Cu II Coordination polymer by using a hydrothermal method, the coordination polymer has the characteristics of stable structure, simple process and good repeatability, the coordination environment of the Cu II Coordination polymer is analyzed and urease inhibition experiment is carried out, the coordination polymer has good inhibition effect on urease activity, can be added into a fertilizer as a novel urease inhibitor, inhibits urease activity, delays urea hydrolysis time, and makes urea hydrolysis blocked, so that soil urea ammonia volatilization is reduced, nitrogen loss is reduced and utilization rate is improved by applying the substance.

Description

Technical Field

[0001] This invention belongs to the field of fertilizers, specifically relating to a Cu II Coordination polymers, their preparation methods, and their applications in the fertilizer field. Background Technology

[0002] Coordination polymers are crystalline materials with a certain degree of regularity formed by the self-assembly of organic ligands and metal ions. Coordination polymers have great application potential in many fields, such as organic and inorganic chemistry, biochemistry, materials science, electrochemistry, and pharmacology.

[0003] Urease activity is a key factor affecting urea hydrolysis. Controlling urease activity in the first step of urea hydrolysis can slow down the hydrolysis rate and reduce nitrogen loss. A common practice is to add an appropriate amount of urease inhibitor to the urea. This inhibitor contains Cu. II Coordination polymers have attracted widespread attention as urease inhibitors, Cu II The coordination polymer not only inhibits the activation process of urease apoprotein, but also fills the active pocket of urease well, establishing an interaction with the active site of urease. This occupies the nickel active site of urease, thereby causing irreversible inhibition of urease activity and blocking the pathway of urea into the active site, thus achieving the effect of inhibiting urease activity. Summary of the Invention

[0004] One of the objectives of this invention is to provide a Cu II Coordination polymers and their preparation methods.

[0005] The second objective of this invention is to provide a Cu II The application of coordination polymers as urease inhibitors in the fertilizer field.

[0006] The technical solution adopted in this invention is: a Cu II Coordination polymer, the Cu II Coordination polymer, monoclinic crystal system, space group C2 / c, Cu II The ion adopts a five-coordinate mode, consisting of two nitrogen atoms from a single N,N′-bis(3-pyridinamide)-1,4-butane ligand, two carboxyl oxygen atoms from a single benzoic acid anion, and one oxygen atom from a coordinated water molecule, exhibiting a distorted tetragonal pyramidal geometry; Cu II The coordination environment of the coordination polymer is shown in (I).

[0007]

[0008] A Cu IIThe preparation method of the coordination polymer includes the following steps: Ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane, benzoic acid, and CuCl2·2H2O are placed in a reaction vessel with a polytetrafluoroethylene liner. Deionized water and sodium hydroxide are added, the reaction vessel is sealed, and a hydrothermal reaction is carried out. After the reaction is completed, the product is washed, filtered, and dried to obtain the target product Cu. II Coordination polymers.

[0009] Preferably, the preparation method described above, wherein the preparation method of the ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane includes the following steps: 1,4-butanediamine is slowly added to a pyridine solution of nicotinic acid, stirred for 15 min, then triphenyl phosphite is added, the mixture is heated under reflux for 6 h, concentrated, and left at room temperature for 24 h to precipitate a white solid, which is then filtered, recrystallized with ethanol, and dried in air to obtain the ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane.

[0010] Preferably, in the above preparation method, the molar ratio of 1,4-butanediamine:nicotinic acid:triphenyl phosphite is 1:(1.5-2):(1.5-2).

[0011] Preferably, in the above preparation method, the hydrothermal reaction is carried out at 120°C for 4 days.

[0012] Preferably, in the above preparation method, the molar ratio of ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane:benzoic acid:CuCl2·2H2O is 1:(1~2):(0.1~2).

[0013] The present invention provides a Cu II Application of coordination polymers as urease inhibitors in fertilizers.

[0014] Preferably, the fertilizer is a nitrogen fertilizer.

[0015] Preferably, the nitrogen fertilizer is urea.

[0016] The beneficial effects of this invention are:

[0017] 1. In this invention, 1,4-butanediamine, nicotinic acid and triphenyl phosphite are selected as raw materials, and nitrogen-containing ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane is obtained by a one-pot process, which makes it easier to coordinate with metal chlorides and increases the number of coordination sites.

[0018] 2. This invention constructs Cu using a hydrothermal method. II Coordination polymers, Cu IIIons inhibit the activation process of urease apoprotein and occupy the binding site near the nickel atom of the urease active center, inhibiting the hydrolysis of urea by urease, delaying the conversion of urea to ammonium nitrogen, and allowing ammonium nitrogen to remain in the soil for a longer period of time for crop absorption.

[0019] 3. The Cu provided by this invention II The coordination polymer effectively inhibits the activity of urease-producing bacteria in the soil, slows down the decomposition rate of urea, and reduces the generation of ammonia / ammonium nitrogen. This, in turn, reduces the conversion of ammonium nitrogen into nitrate nitrogen, prolonging the utilization time of available nitrogen (ammonium nitrogen and nitrate nitrogen) for plants while reducing ammonia volatilization loss and nitrate nitrogen leaching. By improving the utilization time of nitrogen fertilizer and reducing nitrogen fertilizer losses in the form of ammonia volatilization and nitrate nitrogen leaching, the utilization rate of fertilizer is improved.

[0020] 4. The Cu provided by this invention II Coordination polymers have the advantages of low dosage, high inhibition rate, long half-life, low toxicity, and low environmental impact. Attached Figure Description

[0021] Figure 1 It is Cu II Coordination environment diagram of coordination polymers.

[0022] Figure 2 It is Cu II X-ray diffraction pattern and simulation data of coordination polymer.

[0023] Figure 3 It is Cu II Half-inhibitory concentration of coordination polymer. Detailed Implementation

[0024] Example 1 Cu II Coordination polymers

[0025] (I) The preparation method is as follows:

[0026] 1. Preparation of ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane:

[0027] 1,4-Butanediamine (1.5 mL, 0.016 mol) was slowly added to a 50 mL pyridine solution of nicotinic acid (4.0 g, 0.032 mol). After stirring for 15 min, triphenyl phosphite (9 mL, 0.032 mol) was added. The mixture was heated under reflux for 6 h, concentrated to 5 mL, and allowed to stand at room temperature for 24 h. A white solid precipitated, which was filtered, recrystallized from ethanol, and dried in air to obtain a white powdery solid, which was the ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane. The reaction formula is as follows:

[0028]

[0029] 2. Cu II Preparation of coordination polymers:

[0030] Ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane (0.03 g, 0.05 mmol), benzoic acid (0.018 g, 0.1 mmol), and CuCl2·2H2O (0.034 g, 0.1 mmol) were placed in a tetrafluoroethylene liner, and 12 mL of deionized water and 1 g of sodium hydroxide were added. The reaction vessel was sealed and placed in a drying oven at 120 °C for hydrothermal reaction for 4 days. After the reaction was completed, the resulting blue blocky crystals were washed, filtered, and dried to obtain the target product Cu. II Coordination polymers, with a yield of approximately 40%.

[0031] (II) Characterization

[0032] Graphite monochromatization of Mo Kα was performed on a Bruker D8-ray diffractometer. Radiation is used as the diffraction source to collect diffraction intensity data from a single crystal. Combined with Cu... II SC-XRD data of coordination polymers were obtained, further yielding Cu II The structural diagram of the coordination polymer is shown below. Figure 1 As shown. Figure 1 The exhibit is metallic Cu II Coordination environment of ions. Cu II The ions adopt a five-coordinate mode, coordinating with two nitrogen atoms from two separate 3-dpyb (3-pyridinamide) ions, two carboxyl oxygen atoms from two separate benzoic acid anions, and an oxygen atom from a coordinated water molecule. (The main bond lengths and bond angles are shown in Table 1), which shows a distorted square pyramidal geometry.

[0033] Table 1. Crystallographic data of coordination polymers

[0034]

[0035]

[0036] Powder diffraction experiments were performed on the crystal using a Bruker D8 Advance X-ray powder diffractometer. Graphite monochromatized CuKα radiation was used, with a wavelength of [wavelength missing]. Solid-state detector, step size 0.01°, step time 0.3 sec, scan range 5°≤2θ≤45°. Prepared Cu II X-ray diffraction patterns and simulation data of coordination polymers are shown below. Figure 2 As shown, by Figure 2It can be seen that the test spectrum and the calculated spectrum are basically consistent, which indicates that the powder phase of the coordination polymer is pure and free of impurities.

[0037] Example 2 Cu II Coordination polymers

[0038] 1. Preparation of ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane: Same as in Example 1.

[0039] 2. Cu II Preparation of coordination polymers:

[0040] Ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane (0.03 g, 0.05 mmol), benzoic acid (0.009 g, 0.05 mmol), and CuCl2·2H2O (0.034 g, 0.1 mmol) were placed in a tetrafluoroethylene liner, and 12 mL of deionized water and 1 g of sodium hydroxide were added. The reaction vessel was sealed and placed in a 120 °C drying oven for hydrothermal reaction for 4 days. After the reaction was completed, the resulting blue blocky crystals were washed, filtered, and dried to obtain the target product Cu. II Coordination polymer, yield approximately 36%.

[0041] Example 3 Cu II Coordination polymers

[0042] 1. Preparation of ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane: Same as in Example 1.

[0043] 2. Cu II Preparation of coordination polymers:

[0044] Ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane (0.06 g, 0.10 mmol), benzoic acid (0.036 g, 0.2 mmol), and CuCl2·2H2O (0.0034 g, 0.01 mmol) were placed in a tetrafluoroethylene liner, along with 12 mL of deionized water and 1 g of sodium hydroxide. The reaction vessel was sealed and placed in a 120 °C drying oven for hydrothermal reaction for 4 days. After the reaction was completed, the resulting blue blocky crystals were washed, filtered, and dried to obtain the target product Cu. II Coordination polymers, with a yield of approximately 33%.

[0045] Example 4 Cu II Application of coordination polymers as urease inhibitors

[0046] (a) Cu II Effect of coordination polymer concentration on urease inhibition

[0047] The method is as follows: Cu prepared in Example 1II The coordination polymers were used in the experiment. 4 mL of Cu at concentrations of 0.3 μM and 0.6 μM were respectively taken. II The coordination polymer (sample dissolved in DMSO:H2O = 1:1) was placed in three centrifuge tubes. 4 mL of 10 KU / L urease (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) was added to each tube. The tubes were incubated at 25°C for 1 hour with a shaking incubator, followed by the addition of phenol red indicator to obtain the test solution. The absorbance of the test solution was immediately measured at 570 nm using a UV-Vis spectrophotometer, and the IC50 of urease was calculated. 50 Value (μM), results as follows Figure 3 .

[0048] Depend on Figure 3 It can be seen that Cu at 0.3 μM and 0.6 μM... II Coordination polymers all inhibit urease. The higher the concentration, the better the inhibitory effect.

[0049] (II) Effects of different inhibitors on the inhibitory effect of urease

[0050] The method is as follows: Cu prepared in Example 1 II The experiment was conducted using coordination polymers. 4 mL of each of the different inhibitors shown in Table 2 was placed in a centrifuge tube, and 4 mL of 10 KU / L urease was added to each tube. After incubation at 25°C for 1 hour in a shaking incubator, phenol red indicator was added to obtain the test solution. The absorbance of the test solution was immediately measured at 570 nm using a UV-Vis spectrophotometer. The inhibitory strength of different inhibitors was calculated, and the results are shown in Table 2.

[0051] The inhibitors selected in Table 2 are common urease inhibitors available on the market. The inhibitory effect is expressed as the urease half-inhibitory concentration (IC50). 50 Value (μM) is used to represent this.

[0052] Table 2. Half-inhibitory concentrations of different inhibitors

[0053]

[0054] As can be seen from Table 2, when Cu II Coordination polymers, as urease inhibitors, have a low half-maximal inhibitory concentration (WMC) for urease, meaning that even small amounts can produce a strong inhibitory effect. Therefore, the Cu of this invention... II Coordination polymers can be added to urea fertilizer as urease inhibitors to inhibit urease activity and prolong the decomposition time of urea. This invention exhibits good inhibitory effects and can act as a urease inhibitor, reducing nitrogen loss in fertilizers and improving fertilizer utilization.

Claims

1. A Cu II Coordination polymers, characterized in that, The Cu II Coordination polymer, monoclinic crystal system, space group C2 / c, Cu II The ion adopts a five-coordinate mode, consisting of two nitrogen atoms from a single N,N′-bis(3-pyridinamide)-1,4-butane ligand, two carboxyl oxygen atoms from a single benzoic acid anion, and one oxygen atom from a coordinated water molecule, exhibiting a distorted tetragonal pyramidal geometry; Cu II The coordination environment of the coordination polymer is shown in (I). （I）； Cu II The preparation method of the coordination polymer includes the following steps: Ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane, benzoic acid, and CuCl2·2H2O are placed in a reaction vessel with a polytetrafluoroethylene liner. Deionized water and sodium hydroxide are added, the reaction vessel is sealed, and a hydrothermal reaction is carried out. After the reaction is completed, the product is washed, filtered, and dried to obtain the target product Cu. II Coordination polymers; The preparation method of the ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane includes the following steps: 1,4-butanediamine is slowly added to a pyridine solution of nicotinic acid, stirred for 15 min, then triphenyl phosphite is added, heated under reflux for 6 h, concentrated, and left at room temperature for 24 h to precipitate a white solid, which is filtered, recrystallized with ethanol, and dried in air to obtain the ligand N,N′-bis(3-pyridinecarboxamide)-1,4-butane; The molar ratio is 1,4-butanediamine:nicotinic acid:triphenyl phosphite = 1:(1.5-2):(1.5-2). The hydrothermal reaction was carried out at 120°C for 4 days. The molar ratio is N,N′-bis(3-pyridinecarboxamide)-1,4-butane:benzoic acid:CuCl2·2H2O = 1:(1~2):(0.1~2).

2. The Cu according to claim 1 II Application of coordination polymers as urease inhibitors in fertilizers.

3. The application according to claim 2, characterized in that, The fertilizer in question is a nitrogen fertilizer.

4. The application according to claim 3, characterized in that, The nitrogen fertilizer mentioned is urea.

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