A divalent copper ion coordination polymer and its preparation method and application

Abstract

The present invention belongs to the technical field of preparation and application of copper ion coordination compounds, and specifically provides a divalent copper ion coordination polymer and a preparation method and application thereof. The present invention uses 1,2-ethylenediamine, isonicotinic acid, and triphenyl phosphite as raw materials to synthesize N,N'-bis(4-pyridinecarboxamide)-1,2-ethane, and then uses it as a ligand to construct a divalent copper ion coordination polymer by a hydrothermal method. The coordination polymer is a triclinic system with a molecular formula of C 21 H 17 CuN2O5 can not only inhibit the activation process of urease apoprotein, but also fill the active pocket of urease well, occupy the active position of urease hydrolysis of urea, and interact with the active site of urease, thereby causing irreversible inhibition of urease activity and achieving the effect of inhibiting urease activity.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation and application of copper ion coordination compounds, and specifically provides a divalent copper ion coordination polymer and a preparation method and application thereof. The divalent copper ion coordination polymer exhibits a good effect of inhibiting urease activity in soil, preventing urea nitrogen from being converted into ammonium nitrogen, and thus improving the utilization rate of urea fertilizer. Background Art

[0002] Coordination polymers are inorganic polymers or zero-dimensional molecular cages with one-dimensional, two-dimensional or three-dimensional structures formed by metal ion centers and organic ligands bonded in a coordination bond manner through a self-assembly process. They have excellent performance and show potential application value in many fields, but they have not been studied in the field of urease activity inhibition. In addition, the traditional method of growing coordination polymer crystals is limited to the solvent evaporation method, while the application of the hydrothermal method can enhance the diffusion effect due to the decrease in solvent viscosity, thereby achieving the crystal growth of the solid component of the solvent. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a divalent copper ion coordination polymer and a preparation method and application thereof, which can not only inhibit the activation process of urease apoprotein, but also can well fill the active pocket of urease, occupy the active position of urease hydrolyzing urea, and interact with the active site of urease, thereby causing irreversible inhibition of urease activity, thereby achieving the effect of inhibiting urease activity.

[0004] The present invention is achieved by first providing a divalent copper ion coordination polymer, wherein the molecular formula of the divalent copper ion coordination polymer is C 21 H 17 CuN2O5, the divalent copper ion is in a five-coordinate mode, coordinated with a nitrogen atom on the pyridine ring from a single N,N′-bis(4-pyridinecarboxamide)-1,2-ethane and four carboxyl oxygen atoms on the benzoate anion.

[0005] Preferably, the divalent copper ion coordination polymer crystal belongs to the triclinic system, and the space group is P-1.

[0006] The present invention also provides a method for preparing a divalent copper ion coordination polymer, comprising the following steps:

[0007] 1) Using N,N′-bis(4-pyridinecarboxamide)-1,2-ethane and benzoic acid as ligands and mixing with a divalent copper ion compound;

[0008] 2) Add a certain amount of deionized water and sodium hydroxide;

[0009] 3) putting the above mixture into a reaction kettle, sealing it, and calcining it at a certain temperature for a certain time to obtain blue-green block crystals, and then washing, filtering and drying the block crystals to obtain a divalent copper ion coordination polymer.

[0010] Preferably, in step 1), the molar ratio of N,N′-bis(4-pyridinecarboxamide)-1,2-ethane, benzoic acid and cupric chloride is 1:1-2:1-2.

[0011] More preferably, in step 3), the sealed reactor is calcined in an oven at 120° C. for 4 days.

[0012] More preferably, the preparation method of N,N′-bis(4-pyridinecarboxamide)-1,2-ethane comprises the following steps:

[0013] 101) adding 1,2-ethylenediamine to the isonicotinic acid pyridine solution and stirring for a certain period of time;

[0014] 102) adding triphenyl phosphite, heating under reflux at a certain temperature for a certain time, and concentrating to a certain volume;

[0015] 103) After being left at room temperature for a certain period of time, a white solid precipitated, which was filtered, recrystallized with ethanol, and dried to obtain a white powdery solid, namely N,N′-bis(4-pyridinecarboxamide)-1,2-ethane.

[0016] More preferably, the molar ratio of 1,2-ethylenediamine, isonicotinic acid and triphenyl phosphite is 1:2:2.

[0017] More preferably, in step 101), stirring is performed for 15 min, in step 102), heating is performed at 120° C. under reflux for 6 h, and concentration is performed to 5 mL, and in step 103), the mixture is allowed to stand at room temperature for 24 h.

[0018] The present invention also provides an application of a divalent copper ion coordination polymer, wherein the divalent copper ion coordination polymer is used as a urease inhibitor in a fertilizer.

[0019] Preferably, the fertilizer is urea.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1. Using 1,2-ethylenediamine, isonicotinic acid and triphenyl phosphite as raw materials, the nitrogen-containing ligand N,N′-bis(4-pyridinecarboxamide)-1,2-ethane is obtained by organic synthesis to make it easier to coordinate with metal chloride and increase the coordination site;

[0022] 2. Copper-based coordination polymers are constructed by the hydrothermal method. Copper ions inhibit the activation process of urease apoprotein and irreversibly occupy the binding sites that should belong to nickel to inhibit the activity of urease. They show a good effect in inhibiting urease activity in the soil, preventing urea nitrogen from being converted into ammonium nitrogen, and allowing crops to grow better.

[0023] That is, the copper-based coordination polymer provided by the present invention has the characteristics of high efficiency, safety, stability and non-pollution, and can be used in fertilizers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a single crystal data diagram of the target product prepared in Example 1;

[0025] Figure 2 The X-ray diffraction pattern of the powder of the target product prepared in Example 1 is compared with the single crystal data simulation pattern;

[0026] Figure 3 This is a half-inhibitory concentration curve of the target product prepared in Example 1 as a urease inhibitor. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] 1. The preparation method of the ligand N,N′-bis(4-pyridinecarboxamide)-1,2-ethane is as follows:

[0029]

[0030] Slowly add 1,2-ethylenediamine (1.0 mL, 0.016 mol) to a 50 mL pyridine solution of isonicotinic acid (4.0 g, 0.032 mol), stir for 15 min, add triphenyl phosphite (9 mL, 0.032 mol), heat under reflux at 120 ° C for 6 h, then concentrate to 5 mL, and leave at room temperature for 24 h to precipitate a white solid, filter, recrystallize with ethanol, and dry in air to obtain a white powdery solid, which is N, N′-bis(4-pyridinecarboxamide)-1,2-ethane.

[0031] Embodiment 1,

[0032] 0.034 g (0.2 mmol) of CuCl2·2H2O, 0.054 g (0.2 mmol) of N,N′-bis(4-pyridinecarboxamide)-1,2-ethane and 0.018 g (0.15 mmol) of benzoic acid were placed in a tetrafluoroethylene liner, and 6 ml of deionized water and 2 ml of 0.1 mol / L NaOH solution were added. The reactor was sealed and calcined in an oven at a constant temperature of 120°C for 4 days to obtain blue-green block crystals. The block crystals were then washed, filtered and dried to obtain a copper coordination polymer with a yield of about 36%.

[0033] Embodiment 2,

[0034] 0.017 g (0.1 mmol) of CuCl2·2H2O and 0.027 g (0.1 mmol) of N,N′-bis(4-pyridinecarboxamide)-1,2-ethane and 0.018 g (0.15 mmol) of benzoic acid were placed in a tetrafluoroethylene liner, and 6 ml of deionized water and 2 ml of 0.1 mol / L NaOH solution were added. The reactor was sealed and calcined in an oven at 120°C for 4 days to obtain blue-green block crystals. The block crystals were then washed, filtered and dried to obtain a copper coordination polymer with a yield of about 32%.

[0035] Embodiment 3,

[0036] 0.034 g (0.2 mmol) of CuCl2·2H2O, 0.054 g (0.2 mmol) of N,N′-bis(4-pyridinecarboxamide)-1,2-ethane and 0.024 g (0.2 mmol) of benzoic acid were placed in a tetrafluoroethylene liner, and 6 ml of deionized water and 2 ml of 0.1 mol / L NaOH solution were added. The reactor was sealed and calcined in an oven at a constant temperature of 120°C for 4 days to obtain blue-green block crystals. The block crystals were then washed, filtered and dried to obtain a copper coordination polymer with a yield of about 28%.

[0037] Determination of the structure of copper coordination polymers:

[0038] Mo Kα was measured on a Bruker D8-ray diffractometer using graphite monochromatization. Radiation was used as the diffraction light source to collect the diffraction intensity data of the single crystal. The copper coordination polymer (SC-XRD data obtained from the blue-green bulk crystal prepared in Example 1, and the structure diagram further obtained is as shown in FIG. Figure 1 shown). Figure 1 The figure shows the coordination environment of the metal Cu(II) ion. The Cu(II) ion adopts a penta-coordinated coordination mode, coordinated with a nitrogen atom on the pyridine ring of the 4-dpyb ligand and four carboxyl oxygen atoms on the benzoate anion. (See Table 1 for main bond lengths and bond angles), showing a tetragonal pyramidal configuration.

[0039] Table 1. Crystallographic data of copper (II) coordination polymers

[0040]

[0041] The powder diffraction experiment of the crystals was carried out using a Bruker D8 Advance X-ray powder diffractometer. Graphite monochromatized CuKα radiation was used, with a wavelength of Solid detector, step length 0.01°, step time 0.3 sec, scanning range 5°≤2θ≤45°. The powder X-ray diffraction pattern obtained in Example 1 matches the single crystal data simulation pattern ( Figure 2 ).

[0042] Determination of urease inhibitory activity:

[0043] The urease used in the test was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. Take 1mL (10KU / L) urease and 1mL of different content coordination polymer samples (samples are dissolved in DMSO, DMSO:H2O=1:1) and mix them evenly. Then, pre-incubate them in a 37°C constant temperature shaking incubator for 1 hour, add 8mL of pH=6.8 (containing 500mM urea and 0.002% phenol red indicator) phosphate buffer with a pH range of 6.8-7.7, and measure its absorbance at 570nm with an ultraviolet spectrometer at intervals of 1 hour. The endpoint of the test is determined by the phenol red indicator, and the test is stopped when the solution changes from light yellow to red.

[0044] Calculation of IC50:

[0045] The modified Koch method was used: lgIC50 = Xm-I(P-(3-Pm-Pn) / 4), where Xm: lg maximum dose, I: lg (maximum dose / adjacent dose), P: sum of positive reaction rates, Pm: maximum positive reaction rate, Pn: minimum positive reaction rate. IC 50 =1.43±0.01μM, while the IC 50 At 0.62 μM <IC 50 <42.74 μM, it can be seen that when this copper-based coordination polymer is used as a urease inhibitor with a low half-inhibitory concentration, the amount of additive used is small ( Figure 3 ). Therefore, it can be concluded that the copper (II) coordination polymer of the present invention can be implemented as a urease inhibitor in urea fertilizer.

Claims

1. A divalent copper ion coordination polymer, characterized in that: The molecular formula of the divalent copper ion coordination polymer is C 21 H 17 CuN2O5, the divalent copper ion is in a five-coordinate mode, coordinated with a nitrogen atom on the pyridine ring from a single N,N′-bis(4-pyridinecarboxamide)-1,2-ethane and four carboxyl oxygen atoms on the benzoate anion.

2. The divalent copper ion coordination polymer according to claim 1, characterized in that The divalent copper ion coordination polymer crystal belongs to the triclinic system, and the space group is P-1.

3. The method for preparing a divalent copper ion coordination polymer according to claim 1, characterized in that: The steps include: 1) Using N,N′-bis(4-pyridinecarboxamide)-1,2-ethane and benzoic acid as ligands and mixing with a divalent copper ion compound; 2) Add a certain amount of deionized water and sodium hydroxide; 3) putting the above mixture into a reaction kettle, sealing it, and calcining it at a certain temperature for a certain time to obtain blue-green block crystals, and then washing, filtering and drying the block crystals to obtain a divalent copper ion coordination polymer.

4. The method for preparing a divalent copper ion coordination polymer according to claim 3, characterized in that: In step 1), the molar ratio of N,N′-bis(4-pyridinecarboxamide)-1,2-ethane, benzoic acid and cupric chloride is 1:1-2:1-2.

5. The method for preparing a divalent copper ion coordination polymer according to claim 3, characterized in that: In step 3), the sealed reactor is calcined in an oven at 120° C. for 4 days.

6. The method for preparing a divalent copper ion coordination polymer according to claim 3, characterized in that: The preparation method of N,N′-bis(4-pyridinecarboxamide)-1,2-ethane comprises the following steps: 101) adding 1,2-ethylenediamine to the isonicotinic acid pyridine solution and stirring for a certain period of time; 102) adding triphenyl phosphite, heating under reflux at a certain temperature for a certain time, and concentrating to a certain volume; 103) After being left at room temperature for a certain period of time, a white solid precipitated, which was filtered, recrystallized with ethanol, and dried to obtain a white powdery solid, namely N,N′-bis(4-pyridinecarboxamide)-1,2-ethane.

7. The method for preparing a divalent copper ion coordination polymer according to claim 6, characterized in that: The molar ratio of 1,2-ethylenediamine, isonicotinic acid and triphenyl phosphite is 1:2:

2.

8. The method for preparing a divalent copper ion coordination polymer according to claim 6, characterized in that: In step 101), the mixture was stirred for 15 min. In step 102), the mixture was heated under reflux at 120° C. for 6 h and concentrated to 5 mL. In step 103), the mixture was allowed to stand at room temperature for 24 h.

9. The use of the divalent copper ion coordination polymer according to claim 1, characterized in that: The divalent copper ion coordination polymer is used as a urease inhibitor in fertilizers.

10. The use of the divalent copper ion coordination polymer according to claim 9, characterized in that: The fertilizer is urea.

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