CN108467494B

CN108467494B - Dinuclear complex and preparation method and application thereof

Info

Publication number: CN108467494B
Application number: CN201810696750.5A
Authority: CN
Inventors: 郭放; 翟晓桐; 段文龙
Original assignee: Liaoning University
Current assignee: Liaoning University
Priority date: 2018-06-29
Filing date: 2018-06-29
Publication date: 2021-10-01
Anticipated expiration: 2038-06-29
Also published as: CN108467494A

Abstract

The invention relates to a binuclear complex and a preparation method and application thereof. The technical scheme is as follows: anhydrous ZnCl is added₂And 3, 5-dimethylpyrazole ligand are ground in a mortar according to the molar ratio of 1:2 for 10min, then transferred into a 25ml conical flask, absolute ethyl alcohol is added to completely dissolve the components, finally, the flask is sealed and punctured, and the flask is stood at room temperature for about 4-6 days to obtain colorless blocky crystals, and then the blocky crystals are washed, filtered and dried to obtain the target product. Zn base prepared by the invention^ⅡThe binuclear complex can be used as a nitrification inhibitor, has the advantages of high inhibition rate, low dosage, good stability, difficult water leaching loss, low toxicity and small environmental impact, and can be applied to fertilizers.

Description

Dinuclear complex and preparation method and application thereof

Technical Field

The invention relates to a metal organic framework material, in particular to a metal organic framework material which has good activity of inhibiting nitrosomonas and delaying NH₄ ⁺-N to NO₃ ^-Conversion of N to NH which makes nitrogen more readily adsorbed by the soil₄ ⁺The form of-N remains in the soil for a longer period of time.

Background

In the field of supramolecular chemistry, organometallic frameworks (MOFs), a functionally diverse material, have been extensively studied. Because of their large specific surface area and pores, and diverse topological structures, MOFs are now used in many fields such as nonlinear optics, superconductivity, catalysis, molecular recognition, biology, adsorption, etc. More importantly, the unique structure and function of the binuclear complex are more and more concerned by researchers. Nitrification inhibitors are collectively referred to as compounds which inhibit the activity of Nitrosomonas and thereby inhibit the conversion of ammonia nitrogen into nitrate nitrogen. The NH in the nitrogen fertilizer can be relieved by adding a nitrification inhibitor into the fertilizer₄ ⁺-N to NO₃ ^-The transformation of N, resulting in an extended period of fertility.

Disclosure of Invention

One of the objects of the present invention is to utilize Zn^ⅡAs a metal node, 3, 5-dimethylpyrazole is selected as an organic ligand, the organic ligand is ground in a certain proportion, and a solution volatilization method is utilized to synthesize the binuclear structureAnd (3) a complex material.

The second purpose of the invention is to use the complex material with a binuclear structure as a nitrification inhibitor to inhibit the activity of nitrosomonas and delay NH₄ ⁺-N to NO₃ ^-Conversion of N to NH which is more readily adsorbed by the soil₄ ⁺The form of-N remains in the soil for a longer period of time.

The technical scheme adopted by the invention is as follows: a preparation method of the binuclear complex comprises the following steps: reacting ZnCl₂Grinding 3, 5-dimethylpyrazole in a mortar, and placing the mixture into a container to be dissolved by adding absolute ethyl alcohol; sealing the container, pricking the hole, standing at room temperature for 3-5 days to obtain colorless blocky crystals, washing, filtering and drying to obtain the target product.

Furthermore, the binuclear complex is ZnCl in molar ratio₂3, 5-dimethylpyrazole-1: 2.

Furthermore, the crystal form of the binuclear complex belongs to a triclinic system, and the space group of the binuclear complex is P-1. The structure of the binuclear complex synthesized by the invention is as follows: in an asymmetric unit, the central ion zinc (ii) has a tetrahedral geometry with 4 ligand donor atoms of 1 chlorine and 3 nitrogens, of which 2 are from 2 bridging bidentate ligands and 1 nitrogen from a monodentate ligand, respectively, ultimately forming a complex with a binuclear structure, 3, 5-dimethylpyrazole.

The application of the binuclear complex as a nitrification inhibitor in fertilizers. Preferably, the fertilizer is a nitrogen fertilizer. More preferably, the nitrogen fertilizer is urea.

The invention has the beneficial effects that: the binuclear complex prepared by the invention has relatively good activity of inhibiting nitrosomonas and delaying NH₄ ⁺-N to NO₃ ^-Conversion of N to NH which makes nitrogen more readily adsorbed by the soil₄ ⁺The form of-N is kept in soil for a long time, the fertilizer effect period of the nitrogen fertilizer can be prolonged, the preparation method is simple, the used solvent is only ethanol, heating is not needed, no pollution is caused, and the method has a good application prospect. Zn base prepared by the invention^ⅡThe binuclear complex is a nitrification inhibitor, has high inhibition rate, low dosage, good stability, difficult water leaching loss, small toxicity and small influence on the environment, and can be applied to fertilizers.

Drawings

FIG. 1 is a diagram of a single crystal thermal ellipsoid of the target product prepared in example 1.

FIG. 2 is a single crystal one-dimensional band plot of the target product prepared in example 1.

FIG. 3 is a powder X-ray diffraction pattern of the target product obtained in example 1 compared with a single crystal data simulation.

Detailed Description

Example 1

(I) preparation method

0.0272g (0.2mmol) of ZnCl₂And 0.0384g (0.4mmol) of 3, 5-dimethylpyrazole were each ground in a mortar for 10 min. Grinding ZnCl₂And 3, 5-dimethylpyrazole were placed in a 25ml Erlenmeyer flask and absolute ethanol was added to completely dissolve them; sealing and pricking holes, standing at room temperature for about 4 days to obtain colorless blocky crystals, and washing, filtering and drying the blocky crystals to obtain the binuclear complex with the yield of 90%.

(II) detection

Mono-colorizing Mo Ka using graphite on a Bruker D8-ray diffractometer

The radiation is used as a diffraction light source, and diffraction intensity data of the single crystal are collected. Taking the prepared binuclear complex, and obtaining data through SC-XRD, and further obtaining the structural diagram as shown in figure 1 and figure 2. The crystal form belongs to a triclinic system, the space group is P-1, in an asymmetric unit, the central ion zinc (II) has a tetrahedral geometric configuration, 4 ligand donor atoms are 1 chlorine and 3 nitrogens, wherein 2 nitrogens are respectively from 2 bridging bidentate ligands, and 1 nitrogen is from 3, 5-dimethylpyrazole monodentate ligands. Binuclear complex molecule is prepared by N4-H4 … Cl1(

∠N4-H4…Cl1 ═ 156.15 °) action of strong hydrogen bonds and C9-H9 … Cl1 (C: (a) ((b))

The action of weak hydrogen bonds of < C9-H9 … Cl1 ═ 147.26 °) forms a 1-dimensional band-like structure, the crystallographic parameters of which are shown in table 1.

The crystals were subjected to powder diffraction experiments using a Bruker D8 advanced X-ray powder diffractometer. Using graphite monochromatized CuKa radiation, wavelength

The step length of the solid detector is 0.01 degrees, the step time is 0.3sec, and the scanning range is more than or equal to 5 degrees and less than or equal to 2 theta and less than or equal to 45 degrees. The X-ray diffraction pattern of the prepared binuclear complex powder is matched with a single crystal data simulation pattern (figure 3).

TABLE 1

Example 2

0.0136g (0.1mmol) of ZnCl is added₂And 0.0192g (0.2mmol) of 3, 5-dimethylpyrazole were each ground in a mortar for 10 min. Grinding ZnCl₂And 3, 5-dimethylpyrazole were placed in a 25ml Erlenmeyer flask and absolute ethanol was added to completely dissolve them; sealing and pricking holes, standing at room temperature for about 5 days to obtain colorless blocky crystals, and washing, filtering and drying the blocky crystals to obtain the binuclear complex with the yield of 86%.

Example 3

0.0068g (0.05mmol) of ZnCl₂And 0.0096g (0.1mmol) of 3, 5-dimethylpyrazole were each ground in a mortar for 10 min. Grinding ZnCl₂And 3, 5-dimethylpyrazole were placed in a 25ml Erlenmeyer flask and absolute ethanol was added to completely dissolve them; sealing and pricking holes, standing at room temperature for about 6 days to obtain colorless blocky crystals, and washing, filtering and drying the blocky crystals to obtain the binuclear complex with the yield of 83%.

Example 4

1. The method comprises the following steps: the bis prepared in example 1 were weighed separately0g (control sample) of nuclear complex, 0.03g, 0.05g, 0.07g and 0.10g (respectively) of nuclear complex are respectively placed in 250mL conical flasks, 10.00g of air-dried soil, 1g of urea and 100mL of phosphate buffer are added into each flask, the conical flasks are simultaneously placed in a constant-temperature culture oscillator (180 revolutions per minute) to be oscillated for 48 hours, then filtration is carried out, and the mass fractions omega of nitrate nitrogen (including nitrite nitrogen) in the solutions of the test sample and the control sample are respectively measured₁。

2. And (3) calculating the nitrification inhibition rate, and calculating the nitrification inhibition rate of the binuclear ligand with different addition amounts, wherein the results are shown in table 2.

Wherein, dN: nitrification inhibition (%);

ω₁-mass fraction of nitrate nitrogen (including nitrite nitrogen) of the sample;

ω₂mass fraction of nitrate nitrogen (including nitrite nitrogen), ω, of control sample₂＝892.5。

TABLE 2 nitrate nitrogen mass fraction ω in test and control solutions₁And nitrification inhibition rate d N

As can be seen from Table 2, the nitrification inhibition rates are all greater than 6% by using the binuclear ligand as the nitrification inhibitor. When the addition amount is gradually increased, the nitrification inhibition rate is not greatly changed, and the optimal addition amount is 5 per mill considering the cost factor. It can therefore be concluded that: the binuclear complex can be used as a nitrification inhibitor in fertilizer urea.

Claims

1. A preparation method of a binuclear complex is characterized by comprising the following steps: reacting ZnCl₂Grinding 3, 5-dimethylpyrazole in a mortar, and placing the mixture into a container to be dissolved by adding absolute ethyl alcohol; sealing the container, pricking hole, standing at room temperature for 4-6 days to obtain colorless block crystal, washing, filtering, and dryingObtaining a target product; the target product was obtained on a Bruker D8-ray diffractometer using graphite monochromated Mo K α radiation of λ = 0.71073 a as the source of the diffracted light, the diffraction intensity data of the single crystal was collected, and the data obtained by SC-XRD gave the structure: the crystal form belongs to a triclinic system and the space group isP-1, in an asymmetric unit, the central ion zinc (ii) has a tetrahedral geometry, 4 ligand donor atoms of 1 chlorine and 3 nitrogens, of which 2 nitrogens are respectively derived from 2 bridged bidentate ligands and 1 nitrogen is derived from a monodentate ligand 3, 5-dimethylpyrazole, the dinuclear complex molecules form a 1-dimensional band structure by the action of strong hydrogen bonds of N4-H4 … Cl1 and weak hydrogen bonds of H9 … Cl1=2.898 a, and C9-H9 … Cl1 at angle C9-H9 … Cl1=147.26 °.

2. The method of claim 1, wherein the method comprises the step of preparing ZnCl in a molar ratio₂3, 5-dimethylpyrazole = 1: 2.