阅读说明：本技术 三维多孔结构的Cd(II)配合物的合成方法和应用 (Synthesis method and application of Cd (II) complex with three-dimensional porous structure ) 是由 贺鸿明 李程鹏 杜淼 于 2018-06-11 设计创作，主要内容包括：本发明公开了一种三维多孔结构的Cd(II)配合物的合成方法和应用,镉配合物化学式为[Cd<Sub>2</Sub>L·(H<Sub>2</Sub>O)<Sub>3</Sub>]<Sub>n</Sub>,其中,所述L为羧基去质子的3,3′,5,5′-四(4-羧基苯基)-4,4′-联苯二胺阴离子配体,合成方法,包括以下步骤：在3,3′,5,5′-四(4-羧基苯基)-4,4′-联苯二胺和镉(II)金属盐中加入N,N-二乙基甲酰胺并使其均匀分散,于100～120℃下保持10～15天后,自然降至室温20～25℃,过滤后得到黄色块状单晶为所述镉配合物,本发明的镉配合物拥有催化位点和丰富的孔道结构,是一种良好的催化剂。(the invention discloses a synthesis method and application of a Cd (II) complex with a three-dimensional porous structure, wherein the chemical formula of the cadmium complex is [ Cd [ ] 2 L·(H 2 O) 3 ] n Wherein, the L is a carboxyl deprotonated 3,3 ', 5,5 ' -tetra (4-carboxyphenyl) -4,4 ' -biphenyldiamine anion ligand, and the synthesis method comprises the following steps: adding N, N-diethylformamide into 3,3 ', 5,5 ' -tetra (4-carboxyphenyl) -4,4 ' -biphenyldiamine and cadmium (II) metal salt, uniformly dispersing the N, N-diethylformamide, keeping the mixture at the temperature of 100-120 ℃ for 10-15 days, naturally cooling the mixture to the room temperature of 20-25 ℃, and filtering the mixture to obtain yellow blocky single crystals serving as the cadmium complexThe porous structure is a good catalyst.)

1. The cadmium complex with a three-dimensional porous structure is characterized in thatThen, it has the chemical formula of [ Cd₂L·(H₂O)₃]_nWherein, the L is a carboxyl deprotonated 3,3 ', 5,5 ' -tetra (4-carboxyphenyl) -4,4 ' -biphenyldiamine anion ligand, and the structure of the L is simply shown as the following formula:

2. A cadmium complex according to claim 1, wherein the basic building block of the cadmium complex comprises: one half of crystallographically independent Cd²⁺(Cd1), one quarter of the total deprotonated L^4-One fourth of crystallographically independent coordinated water molecule H₂O (4) and one half of crystallographically independent coordinated water molecule H₂O(3)。

3. The cadmium complex according to claim 2, wherein each Cd is²⁺Is connected with N1, O1, O2, O3, O4, O1 'and O2', and N1 is from the first L^4-O1 and O2 from the second L^4-Two oxygens in the same carboxyl group of (A), O1 'and O2', are from the third L^4-Two oxygen atoms in the same carboxyl group, O3, are derived from a water molecule H₂O (3), O4 from another water molecule H₂O(4)。

4. A cadmium complex according to claim 3, wherein the cadmium complex has a unit cell parameter of α＝90.00°，β＝97.809(5)，γ＝90.00°，Z＝4。

5. a cadmium complex as claimed in claim 4, wherein the decomposition of the three-dimensional skeleton of the cadmium complex is initiated when the temperature is raised to 450 ℃ and 500 ℃, and the remaining residue is the metal oxide CdO.

6. A synthesis method of the cadmium complex as claimed in any one of claims 1 to 5, comprising the steps of:

Adding N, N-diethylformamide into 3,3 ', 5, 5' -tetra (4-carboxyphenyl) -4,4 '-biphenyldiamine and cadmium (II) metal salt, uniformly dispersing the N, N-diethylformamide, keeping the mixture at 100-120 ℃ for 10-15 days, naturally cooling to room temperature of 20-25 ℃, and filtering to obtain yellow blocky single crystal serving as the cadmium complex, wherein the molar ratio of the cadmium (II) metal salt to the 3, 3', 5,5 '-tetra (4-carboxyphenyl) -4, 4' -biphenyldiamine is (4-4.4): 1.

7. The synthesis method according to claim 6, wherein the ratio of the mass fraction of the cadmium (II) metal salt to the volume fraction of N, N-diethylformamide is (4-4.4): (266-350), wherein the unit of the parts by weight of the substances is mmol, and the unit of the parts by volume is mL.

8. The synthesis method according to claim 7, wherein the yellow bulk single crystal obtained after filtration is washed and dried, wherein the washing agent is N, N-dimethylacetamide, and the drying temperature is 20-25 ℃.

9. Cadmium complex as claimed in any one of claims 1 to 5 in CO₂use in chemical immobilization to form cyclic carbonates.

10. The application of claim 9, wherein epichlorohydrin and tetrabutylammonium bromide in a molar ratio of 1 (0.15-0.20) are dispersed in acetonitrile, the cadmium complex is added as a heterogeneous catalyst, and the reaction is carried out at 80-85 ℃ for 24-36 hours in a carbon dioxide environment with one atmosphere pressure, wherein the conversion rate of the epichlorohydrin into the cyclic carbonate is up to 100%, and the mass part ratio of the cadmium complex to the epichlorohydrin is 50: (0.5-1.5), wherein the unit of the mass parts is mg, and the unit of the mass parts of the substances is mmol;

The ratio of the mass parts of the epichlorohydrin to the volume parts of the acetonitrile is 1: (2-3);

The cadmium complex serving as the heterogeneous catalyst still keeps the original framework structure after being recycled for 3-6 times.

Technical Field

The invention belongs to the technical field of coordination compounds, crystallography and catalysis, and particularly relates toA synthesis method and application of Cd (II) complex with a three-dimensional porous structure are disclosed, wherein the three-dimensional porous complex is obtained by self-assembly of organic ligand 3,3 ', 5,5 ' -tetra (4-carboxyphenyl) -4,4 ' -biphenyldiamine and cadmium (II) ions. Due to the open pore structure and rich catalytic sites, the catalyst can be used as a heterogeneous catalyst for chemically fixing CO₂and an epoxy compound to give a cyclic carbonate.

Background

At present, the world is facing huge environmental pollution problems, especially global warming, mainly due to large amounts of CO₂The emission of gases causes a series of environmental problems. Therefore, numerous materials scientists and chemists have focused on designing diverse materials for capturing and converting CO₂Useful chemicals are, for example: cyclic carbonates, and the like. Not only can CO be solved by the method₂The resulting environmental problem can also be converted to industrial feedstock as a source of C1. The materials commonly used at present mainly comprise various metal oxides, polymers, high molecular materials, molecular sieves, various composite materials and the like. However, they still have many problems that limit their applications, such as: high cost, poor stability, poor selectivity, harsh reaction conditions and the like. Therefore, a more excellent material is designed and synthesized for capturing and converting CO₂Is one of the problems which are urgently needed to be solved at present.

coordination polymers, as a new class of organic-inorganic hybrid crystal materials, are three-dimensional periodic solid materials mainly composed of inorganic metal and organic ligand through coordination bonds, and have a plurality of unique advantages, such as: rich pore canal structure, high specific surface area, designability and diversity of structure, and the like. The characteristics lead the material to show excellent effects in various fields such as heterogeneous catalysis, fluorescence detection, adsorption separation and the like, and is expected to produce application value in industry. In recent decades, coordination polymers have been the material of interest to many scientists in many fields such as coordination chemistry, crystallography and materials science. Extensive scientists have tried to design and synthesize different complex materials with rich channels, a large number of lewis base sites and open poresMetal sites, and the like. And hopefully utilize such multifunctional materials for heterogeneous catalysts to catalyze CO₂And an epoxy compound. However, the research in this direction is relatively rare at present, and many problems to be solved are also faced, such as: poor stability, low selectivity, high temperature and high pressure requirements, etc. To date, there has been no report of attempts to use 3,3 ', 5,5 ' -tetrakis (4-carboxyphenyl) -4,4 ' -biphenyldiamine (abbreviated as H), a rigid organic ligand containing an amino group₄L) for the construction of a catalyst for the chemical immobilization of CO₂The porous coordination polymer material of (1).

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a cadmium complex with a three-dimensional porous structure, the cadmium complex uses rigid tetracarboxylic acid 3,3 ', 5,5 ' -tetra (4-carboxyphenyl) -4,4 ' -biphenyldiamine containing amino as an organic ligand, four carboxylic acid functional groups of the ligand are deprotonated and then are combined with cadmium ions to construct a crystal material with a long and narrow pore channel structure, and the finally obtained material (cadmium complex) has rich pore channel structures and exposed metal sites.

The invention also aims to provide a synthesis method of the cadmium complex with the three-dimensional porous structure, which is simple and easy to operate, simple in required equipment and good in reproducibility.

It is another object of the present invention to provide the cadmium complex in CO₂Application of cadmium complex of the invention to CO in chemical fixation of cyclic carbonate₂The cyclic carbonate synthesized by the catalyst and the epoxy compound has remarkable catalytic effect and excellent recycling capability, and can be widely applied to the field of catalytic crystal materials.

the purpose of the invention is realized by the following technical scheme.

A cadmium complex with a three-dimensional porous structure has a chemical formula of [ Cd₂L·(H₂O)₃]_nWherein, the L is a carboxyl deprotonated 3,3 ', 5,5 ' -tetra (4-carboxyphenyl) -4,4 ' -biphenyldiamine anion ligand, and the structure of the L is simply shown as the following formula:

In the above technical solution, the basic structural unit of the cadmium complex includes: one half of crystallographically independent Cd²⁺(Cd1), one quarter of the total deprotonated L^4-One fourth of crystallographically independent coordinated water molecule H₂O (4) and one half of crystallographically independent coordinated water molecule H₂O(3)。

In the above technical scheme, each Cd²⁺Is connected with N1, O1, O2, O3, O4, O1 'and O2', and N1 is from the first L^4-O1 and O2 from the second L^4-Two oxygens in the same carboxyl group of (A), O1 'and O2', are from the third L^4-Two oxygen atoms in the same carboxyl group, O3, are derived from a water molecule H₂O (3), O4 from another water molecule H₂O(4)。

In the above technical scheme, the unit cell parameter of the cadmium complex is

α＝90.00°，β＝97.809(5)，γ＝90.00°，Z＝4。

In the technical scheme, when the temperature is increased to 450-500 ℃, the three-dimensional framework of the cadmium complex starts to decompose, and the residual residue is the metal oxide CdO.

In another aspect of the present invention, a method for synthesizing the cadmium complex is further included, which comprises the following steps:

Adding N, N-diethylformamide into 3,3 ', 5, 5' -tetra (4-carboxyphenyl) -4,4 '-biphenyldiamine and cadmium (II) metal salt, uniformly dispersing the N, N-diethylformamide, keeping the mixture at 100-120 ℃ for 10-15 days, naturally cooling to room temperature of 20-25 ℃, and filtering to obtain yellow blocky single crystal serving as the cadmium complex, wherein the molar ratio of the cadmium (II) metal salt to the 3, 3', 5,5 '-tetra (4-carboxyphenyl) -4, 4' -biphenyldiamine is (4-4.4): 1.

In the technical scheme, the ratio of the mass parts of the cadmium (II) metal salt to the volume parts of the N, N-diethylformamide is (4-4.4): (266-350), wherein the unit of the parts by weight of the substances is mmol, and the unit of the parts by volume is mL.

In the technical scheme, the yellow blocky single crystal obtained after filtration is washed and dried, wherein a washing agent is N, N-dimethylacetamide, and the drying temperature is 20-25 ℃.

In another aspect of the invention, the cadmium complex is in CO₂Use in chemical immobilization to form cyclic carbonates.

In the technical scheme, epichlorohydrin and tetrabutylammonium bromide with the molar ratio of 1 (0.15-0.20) are dispersed in acetonitrile, then the cadmium complex is added as a heterogeneous catalyst, the reaction is carried out for 24-36 hours at 80-85 ℃ in a carbon dioxide environment with one atmosphere pressure, the conversion rate of the epichlorohydrin into cyclic carbonate is up to 100%, wherein the mass part ratio of the cadmium complex to the epichlorohydrin is 50: (0.5-1.5), wherein the unit of the mass part is mg, and the unit of the mass part is mmol.

In the technical scheme, the ratio of the mass parts of the epichlorohydrin to the volume parts of the acetonitrile is 1: (2-3).

In the technical scheme, the cadmium complex serving as the heterogeneous catalyst still keeps the original framework structure after being recycled for 3-6 times.

Compared with the prior art, the invention has the beneficial effects that:

1. the Cd (II) metal-organic coordination compound (cadmium complex) provided by the invention has catalytic sites and rich pore channel structures, and is a good catalyst.

2. the invention synthesizes the Cd (II) porous complex (cadmium complex) containing 3,3 ', 5,5 ' -tetra (4-carboxyphenyl) -4,4 ' -biphenyldiamine by a solvothermal method, the reaction operation is simple and easy, the required equipment is simple, the reproducibility is good, and the prepared complex has the advantages of high yield, good thermal stability and the like.

3. Can be widely applied in the field of catalytic crystal materials for catalyzing CO₂When the cyclic carbonate is chemically fixed, the conversion rate is up to 100 percent.

Drawings

FIG. 1 is a diagram showing coordination environments of Cd (II) porous complexes of 3,3 ', 5,5 ' -tetrakis (4-carboxyphenyl) -4,4 ' -biphenyldiamine obtained in example 1;

FIG. 2 is a three-dimensional structural diagram of Cd (II) of 3,3 ', 5,5 ' -tetrakis (4-carboxyphenyl) -4,4 ' -biphenyldiamine obtained in example 1;

FIG. 3 is a graph comparing the experimental and theoretical X-ray powder diffraction (PXRD) patterns of Cd (II) of 3,3 ', 5,5 ' -tetrakis (4-carboxyphenyl) -4,4 ' -biphenyldiamine obtained in example 1;

FIG. 4 is a thermogravimetric analysis graph of a Cd (II) porous complex of 3,3 ', 5,5 ' -tetrakis (4-carboxyphenyl) -4,4 ' -biphenyldiamine obtained in example 1;

FIG. 5 is a X-ray powder diffraction (PXRD) pattern for recycling of the cyclic carbonate product from epichlorohydrin and carbon dioxide using the Cd (II) porous complex of 3,3 ', 5,5 ' -tetrakis (4-carboxyphenyl) -4,4 ' -biphenyldiamine obtained in example 1.

Detailed Description

Cadmium nitrate hexahydrate (98%) used in the experimental procedure was purchased from Tianjin Schens, and N, N-diethylformamide (analytically pure) was purchased from Shanghai Mirrel chemical technology, Inc.

3,3 ', 5,5 ' -tetrakis (4-carboxyphenyl) -4,4 ' -biphenyldiamine was synthesized in the literature: wen, h. -m.; li, B.; wang, h.; krishna, r.; chen, B.high acetyl/ethylene separation in amino acids zinc (II) metal-organic frame with low binding power, chem.Commun, 2016,52, 1166-.

All drugs and reagents were used directly without further purification.

The chemical formula of the cadmium complex is [ Cd ]₂L·(H₂O)₃]_nL is a carboxyl groupDeprotonated 3,3 ', 5,5 ' -tetrakis (4-carboxyphenyl) -4,4 ' -biphenyldiamine anionic ligand, L has the following structural formula:

The basic structural unit of the cadmium complex comprises: one half of crystallographically independent Cd²⁺(Cd1), one quarter of the total deprotonated L^4-One fourth of crystallographically independent coordinated water molecule H₂O (4) and one half of crystallographically independent coordinated water molecule H₂O(3)。

Each Cd²⁺Is connected with N1, O1, O2, O3, O4, O1 'and O2', and N1 is from the first L^4-O1 and O2 from the second L^4-Two oxygens in the same carboxyl group of (A), O1 'and O2', are from the third L^4-Two oxygens in the same carboxyl group, O3, are derived from O3 of one water molecule and O4 are derived from O4 of another water molecule.

the technical scheme of the invention is further explained by combining specific examples.