Preparation method of NiII-containing coordination polymer and research on inhibition effect of NiII-containing coordination polymer on soil urease and nitrifying bacteria

Abstract

The invention discloses a preparation method of a NiII-containing coordination polymer and research on the inhibition effect of the NiII-containing coordination polymer on soil urease and nitrifying bacteria, and the preparation method comprises the following steps: synthesizing N, N-dimethylformamide by taking pyridine-3-carboxylic acid and 1, 2-ethylenediamine as raw materials; the invention discloses a novel coordination polymer [Ni (1, 4-chdc) (3-dpy) (H2O) 2], which is prepared by the following steps of: synthesizing N, N '-bis (3-pyridinecarboxamide)-1, 2-ethane by using NiCl2. 2H2O, the synthesized N, N'-bis (3-pyridinecarboxamide)-1, 2-ethane and 1, 4-cycloadipic acid through a hydrothermal method, and researching the influence of the novel coordination polymer [Ni (1, 4-chdc) (3-dpy) (H2O) 2] as an inhibitor on soil urease and nitrifying bacteria by analyzing the crystal structure of the novel coordination polymer [Ni (1, 4-chdc) (3-dpy) (H2O) 2]. The research on the compound as an inhibitor reduces the conversion of urea from urea N to ammonium nitrogen and the conversion of ammonium nitrogen to nitrate nitrogen, improves the utilization rate of the fertilizer urea and the stability of the urea, reduces environmental pollution and improves the grain yield. Compared with a traditional inhibitor, the novel NiII coordination polymer serving as a urease and nitrification inhibitor has the advantages of longer half-life period, small toxic and side effects, low preparation cost and more comprehensive functions, the utilization rate of nitrogen fertilizer urea can be greatly increased, the grain yield is increased, and the environmental pollution is reduced.

Description

Technical Field

[0001] This invention relates to a material containing Ni Ⅱ The application of metal-organic frameworks (MOFs) with Ni as the central atom in the fertilizer field, specifically, this invention relates to a Ni-containing... Ⅱ Metal-organic frameworks (MOFs) can be used as fertilizer additives to inhibit the conversion of urea into ammonium nitrogen and ammonium nitrogen into nitrate nitrogen in soil, thereby increasing the duration of available nitrogen in the soil, increasing grain yield, and reducing environmental pollution. Background Technology

[0002] Coordination polymers (CPs) are a class of inorganic-organic hybrid materials formed by coordination bonds between a metal center (metal ion or metal cluster) and an organic ligand. They are characterized by rich spatial structures and tunable properties. When used as fertilizer additives, metal-polymer particles can remain near fertilizer particles, forming a localized high-concentration inhibition zone, effectively protecting the fertilizer from rapid decomposition. After the fertilizer is applied into the soil, the polymer acts as a "warehouse," continuously and controllably releasing inhibitory metal ions through slow degradation, ion exchange, or diffusion. This ensures that it maintains an effective inhibitory concentration and activity throughout the entire growth cycle, resulting in a longer duration of action and a more stable inhibitory effect, while avoiding excessively high initial concentrations of inhibitory materials that could negatively impact the soil microbial community. However, existing technologies have the following drawbacks:

[0003] 1. It cannot inhibit the activity of soil urease and nitrifying bacteria, shortening the conversion of urea to ammonium nitrogen and ammonium nitrogen to nitrate nitrogen in the soil, so that nitrogen in the form of readily available nitrogen that is more easily adsorbed by the soil cannot be retained in the soil for a long time.

[0004] 2. The inhibitory effect on soil urease and nitrifying bacteria could not be clearly determined.

[0005] 3. High cost, low efficiency, and easy leaching greatly increase the risk of metal elements spreading into the environment, making it unsuitable for use in fertilizers. Summary of the Invention

[0006] One of the objectives of this invention is to synthesize the ligand N,N'-bis(3-pyridinecarboxamide)-1,2-ethane using pyridine-3-carboxylic acid and 1,2-ethylenediamine as raw materials, and to prepare coordination polymers.

[0007] The second objective of this invention is to construct Ni-containing structures via a hydrothermal method. ⅡCoordination polymers reduce the conversion of urea nitrogen to ammonium nitrogen and ammonium nitrogen to nitrate nitrogen during urea application, reduce NH3 volatilization after urea application and subsequent N2O volatilization, reduce nitrogen loss from urea and the serious environmental and economic problems it causes, and improve the utilization rate of urea in the soil.

[0008] A Ni-containing Ⅱ The preparation method of the coordination polymer includes the following steps: N,N'-bis(3-pyridinecarboxamide)-1,2-ethane is synthesized from pyridine-3-carboxylic acid and 1,2-ethylenediamine as raw materials, and then synthesized by hydrothermal method with NiCl2·2H2O and 1,4-cyclohexane. The structure of the blue-green bulk crystals was determined by X-ray single-crystal diffraction.

[0009] Furthermore, the molar ratio of NiCl2·2H2O to N,N'-bis(3-pyridinecarboxamide)-1,2-ethane and 1,4-cyclohexanoic acid is 2:1:1.5.

[0010] Furthermore, the Ni-containing Ⅱ The coordination polymer has a triclinic crystal system and a space group of P-1.

[0011] Contains Ni Ⅱ The application of secondary coordination polymers as fertilizer additives in fertilizers, wherein the fertilizer is nitrogen fertilizer, and the nitrogen fertilizer is urea.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] 1. It can effectively inhibit the activity of soil urease and nitrifying bacteria, delay the conversion of urea to ammonium nitrogen and ammonium nitrogen to nitrate nitrogen in the soil, so that nitrogen is retained in the soil for a longer time in the form of readily available nitrogen that is more easily adsorbed by the soil, thereby improving the utilization rate and stability of urea fertilizer, reducing environmental pollution, and increasing grain yield.

[0014] 2. Methods for determining soil urease activity and nitrification potential: Ultraviolet spectrophotometer was used to determine their inhibitory ability on soil urease and nitrifying bacteria.

[0015] 3. This invention has advantages such as low cost, high efficiency, and low leaching risk, greatly reducing the risk of metal elements diffusing into the environment and significantly improving environmental friendliness. Therefore, it contains Ni. Ⅱ Application of secondary coordination polymers as fertilizer additives in fertilizers. Attached Figure Description

[0016] Figure 1 A single-cell diagram of the target product crystal prepared in Example 1;

[0017] Figure 2 The infrared absorption spectrum of the target product prepared in Example 1;

[0018] Figure 3 This is a comparison diagram of the powder X-ray diffraction pattern of the target product obtained in Example 1 and the simulated pattern of single crystal data;

[0019] Figure 4 The graph shows the inhibitory effect of the coordination polymer on urease activity in Example 5 (soil culture).

[0020] Figure 5 The graph shows the nitration activity inhibition effect of the coordination polymer in Example 5 (soil culture).

[0021] Figure 6 Flowchart for the preparation of ligand N,N'-bis(3-pyridinecarboxamide)-1,2-ethane. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The preparation method of the ligand N,N'-bis(3-pyridinecarboxamide)-1,2-ethane is as follows:

[0024] 1,2-Ethylenediamine (1 mL, 0.016 mol) was slowly added to a 50 mL pyridine solution of pyridine-3-carboxylic acid (4.0 g, 0.032 mol). After stirring for 15 min, triphenyl phosphite (9 mL, 0.032 mol) was added, and the mixture was heated under reflux for 6 h. The solution was then concentrated to 5 mL, and after standing at room temperature for 24 h, a white solid precipitated. The solid was filtered, recrystallized from ethanol, and dried in air to obtain a white powdery solid. Figure 6 As shown.

[0025] Example 1: Preparation of N,N'-bis(3-pyridinecarboxamide)-1,2-ethane

[0026] 1,2-Ethylenediamine (1 mL, 0.016 mol) was slowly added to a 50 mL pyridine solution of pyridine-3-carboxylic acid (4.0 g, 0.032 mol). After stirring for 15 min, triphenyl phosphite (9 mL, 0.032 mol) was added, and the mixture was heated under reflux for 6 h. The solution was then 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 with a yield of 63%.

[0027] Ni Ⅱ Preparation methods of coordination polymers

[0028] 0.047 g (0.2 mmol) of NiCl₂·2H₂O, 0.027 g (0.1 mmol) of N,N'-bis(3-pyridinecarboxamide)-1,2-ethane, and 0.026 g (0.15 mmol) of 1,4-cyclohexane were placed in a hydrothermal reactor. 2 ml (0.1 mol / L) of sodium hydroxide solution was added to the reactor, followed by 4 ml of distilled water. The reactor was then placed in an oven at 120°C and heated for 4 days to obtain fine blue-green crystals. These crystals were then washed repeatedly with distilled water, filtered, and dried to obtain more blue-green crystals.

[0029] Example 1 A Ni-containing Ⅱ Preparation of coordination polymers

[0030] 0.047 g (0.2 mmol) of NiCl₂·2H₂O, 0.027 g (0.1 mmol) of N,N'-bis(3-pyridinecarboxamide)-1,2-ethane, and 0.026 g (0.15 mmol) of 1,4-cyclohexane were placed in a hydrothermal reactor. 2 ml (0.1 mol / L) of sodium hydroxide solution was added to the reactor, followed by 4 ml of distilled water. The reactor was then heated in an oven at 120 °C for 4 days to obtain fine blue-green crystals. These crystals were then washed repeatedly with distilled water, filtered, and dried to obtain blue-green crystals. The yield was approximately 40%.

[0031] Example 2 A Ni-containing Ⅱ Preparation of coordination polymers

[0032] 0.034 g (0.2 mmol) of NiCl₂·2H₂O, 0.027 g (0.1 mmol) of N,N'-bis(3-pyridinecarboxamide)-1,2-ethane, and 0.026 g (0.15 mmol) of 1,4-cyclohexane were placed in a hydrothermal reactor. 2 ml (0.1 mol / L) of sodium hydroxide solution was added to the reactor, followed by 4 ml of distilled water. The reactor was then heated in an oven at 120 °C for 4 days to obtain fine blue-green crystals. These crystals were then washed repeatedly with distilled water, filtered, and dried to obtain blue-green crystals. The yield was approximately 42%.

[0033] Example 3 A Ni-containing Ⅱ Preparation of coordination polymers

[0034] 0.034 g (0.2 mmol) of NiCl₂·2H₂O, 0.027 g (0.1 mmol) of N,N'-bis(3-pyridinecarboxamide)-1,2-ethane, and 0.026 g (0.15 mmol) of 1,4-cyclohexane were placed in a hydrothermal reactor. 2 ml (0.1 mol / L) of sodium hydroxide solution was added to the reactor, followed by 4 ml of distilled water. The reactor was then heated in an oven at 120 °C for 4 days to obtain fine blue-green crystals. These crystals were washed repeatedly with distilled water, filtered, and dried to obtain blue-green crystals. The yield was approximately 39%.

[0035] Ni Ⅱ Determination of coordination polymer structure:

[0036] Structural data of the polymer were obtained using SC-XRD technology. A suitable single-crystal sample (approximately 0.2 × 0.2 × 0.2 mm³) was selected from the blue-green bulk crystal prepared in Example 1, fixed to the top of a glass fiber with Vaseline, and mounted on the sample stage of a single-crystal diffractometer. Diffraction data were acquired at room temperature using graphite-monochromatic Mo Kα radiation (λ = 0.71073 Å) in a φ-ω scanning mode, with a scan width of 0.3° / frame, a detector distance of 50 mm, a tube voltage of 50 kV, and a tube current of 30 mA. The data acquisition range covered the entire reciprocal lattice space (hkl = ±h, ±k, ±l), collecting a total of 1800 diffraction images. Each frame had an exposure time of 10 seconds, ensuring a data integrity factor R. int < 0.05. The obtained data, and further obtained structural diagrams (such as...) Figure 1(As shown). The blue-green blocky crystals prepared in Example 1 were used. 1-2 mg of the sample was mixed and ground with 100-200 mg of dry KBr powder using the KBr pelleting method. The mixture was then pressed into transparent sheets using a pellet press. The infrared spectrometer was set with scanning parameters (wavenumber range 4000-500 cm⁻¹, resolution 4 cm⁻¹) for background scanning. The sample was then placed in the sample for scanning to obtain the infrared spectrum (as shown). Figure 2 (As shown). Its crystal form belongs to the triclinic crystal system, space group P-1. The central ion Ni(II) has a six-coordinate structure, which coordinates with nitrogen atoms from the pyridine rings of two different L ligands, oxygen atoms from the two 1,4-cyclohexanoic acid anions, and oxygen atoms from the two water molecules to form a spindle-shaped structure. Each metallic Ni(II) ion is surrounded by four organic ligands and two water molecules (two bridging N,N'-bis(3-pyridinecarboxamide)-1,2-ethane, two bridging 1,4-cyclohexanoic acid, and two coordinated water molecules). The central Ni(II) ion forms spindle-shaped structures with the N1 atom of the ligand N1,N4-bis(3-pyridyl)-2-butenamide through Ni-N1 (2.0991 Å) coordination bonds, the O1 atom of the ligand 1,4-cyclohexanoic acid through Ni-O1 (2.0711 Å) coordination bonds, and the O1W (2.0933 Å) coordination bonds in the water molecule. Their crystallographic parameters are shown in Table 1.

[0037] Table 1

[0038]

[0039] Powder diffraction experiments were performed on the crystal using a Bruker D8 Advance X-ray powder diffractometer. Graphite monochromatic CuKα radiation was used at a wavelength λ = 1.54056 Å, with a solid-state detector, a step size of 0.02°, a scan speed of 0.1 / s, and a scan range of 5° ≤ 2θ ≤ 50°. The powder X-ray diffraction pattern obtained in Example 1 matches the simulation pattern obtained from the single-crystal data, as shown... Figure 3 As shown.

[0040] Example 4 Ni Ⅱ Determination of urease and nitration activity inhibition by coordination polymers (soil culture)

[0041] 1. Verification Experiment:

[0042] Taking the blue-green blocky crystals prepared in Example 1 as an example, a soil cultivation verification experiment was conducted at the Shenyang Institute of Applied Ecology, Chinese Academy of Sciences. 500 g of air-dried soil (passed through a 10-mesh sieve) and corresponding amounts of nitrogen fertilizer (urea), phosphorus fertilizer (superphosphate), potassium fertilizer (potassium chloride), and coordination polymer were accurately weighed. The amounts of urea, superphosphate, and potassium chloride added were 0.1857 g / kg soil, 0.05915 g / kg soil, and 0.06345 g / kg soil, respectively. The amount of coordination polymer added was 0.8% of the fertilizer amount. The nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, and coordination polymer were thoroughly shaken until uniformly mixed. Then, the mixture was mixed with 5 g of soil, then with 45 g of soil, then with 150 g of soil, then with 300 g of soil, gradually increasing the mixture until the fertilizer and coordination polymer were fully mixed with the soil. A mixture of soil and fertilizer was added to a culture container, and the weight of the container and soil (A) was recorded. Then, 100 ml of water was evenly added to the soil surface, and the total mass (B) of the container, soil, and solution was recorded. The mass of the container and soil was measured before and after each soil sampling, and water was added to the original amount if the soil moisture was insufficient. After each water addition, the container opening was sealed with Para film and placed in a 25°C constant temperature incubator. Soil samples were taken on days 3, 7, 15, and 30 after incubation to measure soil urease and nitrification potential activities.

[0043] 2. Comparative experiment:

[0044] The experimental conditions were the same as those in the verification experiment, except that Ni from Example 1 was not added to the fertilizer. Ⅱ Coordination polymers.

[0045] 3. Results

[0046] The urease activity in the experimental soil was significantly lower than that in the control soil on days 3, 7, and 15, with decreases of 8.67%, 8.50%, and 2.23%, respectively, indicating that Ni Ⅱ The coordination polymer exhibited an inhibitory effect on urease activity, with significant inhibition observed on days 3 and 7. Simultaneously, the nitrification potential activity in the experimental soil was significantly lower than that in the control soil on days 7, 15, and 30, with reductions of 20.81%, 17.92%, and 6.48%, respectively, indicating that Ni... Ⅱ Coordination polymers have a dual-control effect of simultaneously inhibiting urease activity and nitration activity.

[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0048] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A Ni-containing Ⅱ The method for preparing coordination polymers is characterized by, Its preparation method includes the following steps: N,N'-bis(3-pyridinecarboxamide)-1,2-ethane was synthesized from pyridine-3-carboxylic acid and 1,2-ethylenediamine. Then, the coordination polymer [Ni(1,4-chdc)(3-dpye)]·3H2O was synthesized from N,N'-bis(3-pyridinecarboxamide)-1,2-ethane, NiCl2·2H2O, and 1,4-cyclohexane using a hydrothermal method, yielding fine blue-green crystals.

2. The synthesis of the ligand N,N'-bis(3-pyridinecarboxamide)-1,2-ethane according to claim 1, characterized in that: The molar ratio of the raw materials 3-pyridine-3-carboxylic acid and 1,2-ethylenediamine is 2:

1.

3. The Ni-containing compound according to claim 1 Ⅱ A method for preparing coordination polymers, characterized in that: The molar ratio of NiCl2·2H2O to N,N'-bis(3-pyridinecarboxamide)-1,2-ethane and 1,4-cyclohexanoic acid is 2:1:1.

5.

4. The Ni according to claims 1 and 3 Ⅱ The preparation method of the secondary coordination polymer is characterized by: The synthesis steps include the following: 1) Place 0.047 g, 0.2 mmol of NiCl2·2H2O, 0.027 g, 0.1 mmol of N,N'-bis(3-pyridinecarboxamide)-1,2-ethane, and 0.026 g, 0.15 mmol of 1,4-cyclohexane into a hydrothermal reactor; 2) Add 2 ml of 0.1 mol / L sodium hydroxide solution to the hydrothermal reactor, and then add 4 ml of distilled water to the hydrothermal reactor; 3) The hydrothermal reactor was placed in an oven at 120°C and fired for 4 days to obtain fine blue-green crystals. The crystals were then washed with distilled water, filtered and dried to obtain the target product. 4) The structure of the blue-green bulk crystal was determined by X-ray single crystal diffraction experiment. Its crystal form belongs to the triclinic crystal system and the space group is P-1.

5. A Ni-containing compound as described in claim 1, 3, or 4 Ⅱ The application of the preparation method of coordination polymers is characterized by: Ni Ⅱ Coordination polymers can be used as fertilizer additives in urea fertilizer.

6. The application according to claim 5, characterized in that: It has a good ability to inhibit the activity of soil urease and nitrifying bacteria, and delays the process of urea to ammonium nitrogen and ammonium nitrogen to nitrate nitrogen in the soil. This allows nitrogen to be retained in the soil for a longer period of time in the form of readily available nitrogen that is more easily adsorbed by the soil. Its inhibitory ability on soil urease and nitrifying bacteria was determined by measuring absorbance with an ultraviolet spectrophotometer using the method of determining soil urease activity and nitrification potential.

7. The application according to claim 1, characterized in that: The fertilizer mentioned is urea.

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