阅读说明：本技术 基于两头吡唑配体的钴链的金属有机框架材料及制备和苯吸附应用 (Metal organic framework material of cobalt chain based on double-end pyrazole ligand, preparation and benzene adsorption application ) 是由 李建荣 何涛 孔祥婧 李铜川 于 2020-12-29 设计创作，主要内容包括：基于两头吡唑配体的钴链的金属有机框架材料及制备和苯吸附应用,属于晶态材料的技术领域。化学分子式为化学分子式为[Co(BPZ-X)],H-2BPZ-X为芳基二(1H-吡唑),X＝Py、Pz、Pm,分别为吡啶基、嘧啶基、吡嗪基。该类金属-有机框架的合成为封闭条件下,有机配体芳基二(1H-吡唑)(H-2BPZ-X)与硝酸钴在N,N-二甲基乙酰胺和水的混合溶液中,经由溶剂热反应得到金属-有机框架材料的晶体；此类金属有机框架材料显示出对芳香族挥发性有机化合物苯的吸附性能。(A metal organic framework material of a cobalt chain based on two-end pyrazole ligands, a preparation method and a benzene adsorption application belong to the technical field of crystalline materials. Chemical formula is the chemical formula [ Co (BPZ-X)]，H 2 BPZ-X is arylbis (1H-pyrazole), X ═ Py, Pz, Pm, pyridinyl, pyrimidinyl, pyrazinyl, respectively. The synthesis of the metal-organic framework is carried out under a closed condition, and an organic ligand aryl di (1H-pyrazole) (H) 2 BPZ-X) and cobalt nitrate in a mixed solution of N, N-dimethylacetamide and water, and obtaining a crystal of the metal-organic framework material through a solvothermal reaction; such metal organic framework materials exhibit enhanced performance with respect to the aromatic VOC benzeneAnd (4) adsorption performance.)

1. A series of double-end pyrazole ligands, which are characterized in that the organic ligand is aryl di (1H-pyrazole) H₂BPZ-X, X stands for aromatic ring, X ═ Ph, Py, Pz, Pm, are phenyl, pyridyl, pyrimidyl, pyrazinyl respectively, the chemical structural formula is:

2. meta-bipitch pyrazole ligands according to claim 1, characterized in that the ligand comprises two pyrazole groups; two pyrazoles in the ligand are in para position to the aromatic ring; the middle aromatic ring is pyridyl, pyrazinyl or pyrimidinyl.

3. The process for the preparation of a meta-bipole pyrazole ligand according to claim 1, comprising the steps of:

firstly, dibromoaryl and tetrahydropyrane protected pyrazole boric acid ester are added into dioxane and water, potassium carbonate and tetrakis (triphenylphosphine) palladium are added, sealing and vacuumizing are carried out, inert gas protection is carried out, and heating reaction is carried out to obtain arylbis (1- (tetrahydro-2H-pyran-2-yl) -1H-pyrazole); then heating aryl bis (1- (tetrahydro-2H-pyran-2-yl) -1H-pyrazole) in ethanol solution of hydrochloric acid for deprotection to obtain aryl bis (1H-pyrazole).

4. A metal-organic framework material based on two-end pyrazole ligand is characterized in that the chemical molecular formula is [ Co (BPZ-X)]，H₂BPZ-X is aryl 1, 4-bis (1H-pyrazole).

5. A class of metal-organic framework materials based on double pyrazole ligands according to claim 4 having identical framework structures, characterized in that the crystal structure of such metal-organic frameworks belongs to the tetragonal system from the point of view of framework connection construction, space group I4₁22。

6. A class of metal-organic framework materials based on double-ended pyrazole ligands according to claim 4, characterized in that in the metal-organic framework all Co atoms are coordinated in a tetrahedral configuration with four N atoms, the coordinated N being derived from the pyrazole groups of four different ligands. N on two pyrazoles in each ligand in the framework participates in coordination, and adjacent metal atoms form a zigzag metal chain-shaped Secondary Building Unit (SBU) through bridged pyrazole groups; the ligands and the metal chain SBU are alternately connected to form a three-dimensional framework structure.

7. A metal-organic framework material based on bipodal pyrazole ligands according to claim 4, characterized in that in the metal-organic framework the bond length of the Co-N bond is inWithin the range. Pi-pi stacking occurs between aromatic rings of two adjacent ligands in the framework, whereinThe distance between the centers is about

8. The method for preparing a metal-organic framework material based on bipitch pyrazole ligands according to claim 4, wherein aryl-bis (1H-pyrazole) (H) is prepared under a sealed condition₂BPZ-X, X ═ Py, Pz, Pm) and cobalt nitrate (Co (NO)₃)₂·6H₂O) in a mixed solution of N, N-Dimethylacetamide (DMA) and deionized water, and obtaining the metal-organic framework crystal through solvothermal reaction; further preferred are the organic ligands aryl 1, 4-bis (1H-pyrazole) (H)₂The molar ratio of BPZ-X, X ═ Py, Pz and Pm) to cobalt nitrate is 1 (1-4), each 0.05mmol of cobalt nitrate corresponds to 1-4 mL of DMA and 0.4-4 mL of deionized water, the temperature of thermal reaction is 80-130 ℃, and the reaction time is 6-48 hours.

9. Use of a class of metal-organic framework materials based on double pyrazole ligands according to claim 4 as adsorbents for aromatic volatile organic compounds.

Technical Field

The invention belongs to the technical field of crystalline materials, and relates to a metal-organic coordination polymer material, which is characterized by a cobalt-chain metal-organic framework material, a preparation method thereof and benzene adsorption performance research.

Background

Metal-Organic Frameworks (MOFs) are three-dimensional framework structures formed by connecting inorganic nodes formed by Metal ions/Metal clusters and Organic ligands through coordination bonds. As a class of organic-inorganic porous materials, MOFs have the characteristics of large specific surface area, high porosity, adjustable porosity, various structures and the like, and have wide application prospects in the fields of gas adsorption/separation, sensing, catalysis and the like.

Benzene and its derivatives are important components of VOCs in urban outdoor atmosphere, mainly derived from automobile exhaust, fuel leakage and the like; they are also a major indoor air pollutant, especially in newly erected buildings, which is extremely harmful to humans. Benzene is a primary carcinogen and can cause various diseases such as leukemia and the like. The development of high-efficiency benzene removal technology and related materials has important significance in many aspects. MOFs have great potential in adsorption. The preparation method has important significance in preparing the MOFs material which has strong adsorption effect on trace benzene in the air and good stability.

Disclosure of Invention

The invention aims to provide a metal organic framework material based on cobalt chains of two pyrazole ligands, a preparation method thereof and benzene adsorption performance research.

The invention relates to a metal-organic framework material based on two-end pyrazole ligand, which is characterized in that the chemical molecular formula is [ Co (BPZ-X)]，H₂BPZ-X is aryl 1, 4-di (1H-pyrazole), X represents an aromatic ring, X ═ Py, Pz and Pm are respectively pyridyl, pyrimidyl and pyrazinyl.

From the perspective of frame connection construction, the crystal structure of the metal-organic frame belongs to the tetragonal system, and space group is I4₁22。

In the metal-organic framework, all Co atoms are coordinated in a tetrahedral configuration with four N atoms, the coordinated N being derived from pyrazole groups of four different ligands. The N on both pyrazoles in each ligand in the framework is involved in coordination, and adjacent metal atoms form a zigzag metal chain-like Secondary Building Unit (SBU) through bridged pyrazole groups. The ligands and the metal chain SBU are alternately connected to form a three-dimensional framework structure.

In the metal-organic framework, the bond of Co-N bondGrow onWithin the range. Pi-pi stacking occurs between aromatic rings of two adjacent ligands in the framework, and the center distance of the aromatic rings is about

A series of novel double-end pyrazole ligands are characterized in that the organic ligand is aryl di (1H-pyrazole) (H)₂BPZ-X, X stands for aromatic heterocycle, X ═ Py, Pz, Pm, is pyridyl, pyrimidyl, pyrazinyl respectively), the chemical structural formula is:

the ligand comprises two pyrazole groups; two pyrazoles in the ligand are in para position to the aromatic ring; the middle aromatic ring is pyridyl, pyrazinyl or pyrimidinyl.

The novel synthesis method of the para-position double-head pyrazole ligand comprises the following two steps:

suzuki coupling: firstly, dibromoaryl and pyrazole boric acid ester protected by tetrahydropyran are added into 1, 4-dioxane and water, potassium carbonate and tetrakis (triphenylphosphine) palladium are added, sealing and vacuumizing are carried out, inert gas is used for protection, and heating reaction is carried out to obtain arylbis (1- (tetrahydro-2H-pyran-2-yl) -1H-pyrazole);

deprotection: heating aryl bis (1- (tetrahydro-2H-pyran-2-yl) -1H-pyrazole) in a hydrochloric acid ethanol solution for deprotection to obtain the aryl bis (1H-pyrazole).

The synthesis method of the metal-organic framework material comprises the following steps:

aryl bis (1H-pyrazole) (H) under sealed conditions₂BPZ-X, X ═ Py, Pz, Pm) and cobalt nitrate (Co (NO)₃)₂·6H₂O) in a mixed solution of N, N-Dimethylacetamide (DMA) and deionized water, and obtaining the metal-organic framework crystal through solvothermal reaction.

Further excellenceThe organic ligand aryl 1, 4-di (1H-pyrazole) (H)₂The molar ratio of BPZ-X, X ═ Py, Pz and Pm) to cobalt nitrate is 1 (1-4), each 0.05mmol of cobalt nitrate corresponds to 1-4 mL of DMA and 0.4-4 mL of deionized water, the temperature of thermal reaction is 80-130 ℃, and the reaction time is 6-48 hours.

The organic ligand synthesized by the invention belongs to a novel double-end pyrazole ligand. The metal-organic framework has better chemical stability, so that the MOFs have potential application in the aspect of adsorption of aromatic volatile organic compounds (benzene).

Drawings

FIG. 1 is a structural diagram of two-end pyrazole ligands used for constructing such metal-organic frameworks.

FIG. 2 shows two-terminal pyrazole ligands H for synthesizing the metal-organic framework₂Synthetic route map of BPZ-Py.

FIG. 3 is a diagram of the inorganic building blocks of the metal-organic framework.

Fig. 4 is a schematic three-dimensional structure of the metal-organic framework.

FIG. 5 is a benzene adsorption isotherm diagram of such metal-organic framework materials.

FIG. 6 shows the drawing of Co (BPZ-Py) penetration in such metal-organic framework materials.

Detailed Description

The present invention will be further illustrated with reference to the following examples, but the present invention is not limited to the following examples.

Example 1:

weighing ligand H₂BPZ-Py (0.06mmol) and Co (NO)₃)₂·6H₂O (0.12mmoL) was placed in a 20mL beaker, 10mL of DMA solution and 6mL of deionized water were added, and the cake was placed in an ultrasonic apparatus and sonicated at room temperature for 5 minutes, after which the solution was transferred to a 20mL Teflon reactor. After sealing, the reaction kettle is placed in an oven at 100 ℃ for reaction for 24 hours. After the reaction is finished, the drying oven is closed, the reaction kettle is opened after the reaction kettle is cooled to room temperature, solid particles obtained in the reaction kettle are filtered and collected, and then DMF and H are sequentially used₂O and MeOH (5 mL. times.3) and observed under a microscope to give a purple red block crystal [ C ]o(BPZ-Py)](yield: 59% based on H)₂BPZ-Py ligand).

Example 2:

weighing ligand H₂BPZ-Py (0.06mmol) and Co (NO)₃)₂·6H₂O (0.12mmoL) was placed in a 20mL beaker, 12mL of DMA solution and 4mL of deionized water were added, and the cake was placed in an ultrasonic apparatus and sonicated at room temperature for 5 minutes, after which the solution was transferred to a 20mL Teflon reactor. After sealing, the reaction kettle is placed in an oven at 120 ℃ for reaction for 24 hours. After the reaction is finished, the drying oven is closed, the reaction kettle is opened after the reaction kettle is cooled to room temperature, solid particles obtained in the reaction kettle are filtered and collected, and then DMF and H are sequentially used₂O and MeOH (5 mL. times.3) and observed under a microscope to give a purplish red block crystal [ Co (BPZ-Py)](yield: 51% based on H)₂BPZ-Py ligand).

Example 3

Weighing ligand H₂BPZ-Pz (0.06mmol) and Co (NO)₃)₂·6H₂O (0.14mmoL) was placed in a 20mL beaker, 10mL of DMA solution and 4mL of deionized water were added, and the cake was placed in an ultrasonic apparatus and sonicated at room temperature for 5 minutes, after which the solution was transferred to a 20mL Teflon reactor. After sealing, the reaction kettle is placed in an oven at 120 ℃ for reaction for 36 hours. After the reaction is finished, the drying oven is closed, the reaction kettle is opened after the reaction kettle is cooled to room temperature, solid particles obtained in the reaction kettle are filtered and collected, and then DMF and H are sequentially used₂O and MeOH (5 mL. times.3) and observed under a microscope to give a purplish red block crystal [ Co (BPZ-Pz) ]](yield: 63% based on H)₂BPZ-Pz ligand).

Example 4

Weighing ligand H₂BPZ-Pm (0.06mmol) and Co (NO)₃)₂·6H₂O (0.18mmoL) was placed in a 20mL beaker, 10mL of DMA solution and 7mL of deionized water were added, and the cake was placed in an ultrasonic apparatus and sonicated at room temperature for 5 minutes, after which the solution was transferred to a 20mL Teflon reactor. After sealing, the reaction kettle is placed in an oven at 130 ℃ for reaction for 24 hours. After the reaction is finished, the drying oven is closed, the reaction kettle is opened after the reaction kettle is cooled to room temperature, and the reaction kettle is put into the reaction kettleFiltering and collecting the solid particles obtained in (1), and then sequentially using DMF and H₂O and MeOH (5 mL. times.3) and observed under a microscope to give a purplish red block crystal [ Co (BPZ-Pm)](yield: 58% based on H)₂BPZ-Pm ligand).

The test results of the products obtained in the above examples are the same, and specifically the following are given:

(1) determination of crystal structure:

selecting a single crystal sample with a proper size, and collecting data by using a Rigaku Supernova single crystal instrument at room temperature. Data collection Using Cu-Ka monochromated by graphite monochromatorA target ray. Data absorption correction was done using SCALE3 absack software. The crystal structure was resolved by direct methods using the program SHELXTL-97. Firstly, determining all non-hydrogen atom coordinates by using a difference function method and a least square method, obtaining the hydrogen atom position by using a theoretical hydrogenation method, and then refining the crystal structure by using SHELXTL-97. The structure is shown in fig. 3 to 4. The crystallographic data are shown in table 1.

TABLE 1 crystallography data for metal organic framework materials

FIG. 1 is a structural diagram of two-end pyrazole ligands for constructing such metal-organic frameworks

FIG. 2 shows the double pyrazole ligand H of the metal-organic framework₂The synthetic route map for BPZ-Py shows: firstly, adding 2, 5-dibromopyridine and tetrahydropyrane protected pyrazole boric acid ester into 1, 4-dioxane and water, adding potassium carbonate and tetrakis (triphenylphosphine) palladium, sealing, vacuumizing, protecting by inert gas, and heating to react to obtain 2, 5-bis (1- (tetrahydro-2H-pyran-2-yl) -1H-pyrazole-4-yl) pyridine; then 2, 5-bis (1-Heating (tetrahydro-2H-pyran-2-yl) -1H-pyrazole-4-yl) pyridine in a hydrochloric acid ethanol solution to remove protection to obtain the 2, 5-bis (1H-pyrazole-4-yl) pyridine.

The structure diagram of the chain inorganic building block of FIG. 3 shows: the inorganic nodes contained in the framework are chain-shaped Co-based SBUs.

The block diagram of fig. 4 shows: a three-dimensional stacking diagram of the metal-organic framework.

(2) Adsorption of aromatic volatile organic compound benzene

FIG. 5 is the adsorption isotherm of the material of the present invention for the aromatic VOC benzene, which shows that the material can effectively adsorb the volatile VOC benzene. FIG. 5 is a benzene adsorption isotherm of the inventive material in a thermostated water bath at 298K, as tested by a gas adsorber.

FIG. 6 shows the Co (BPZ-Py) desorption diagram of the material of the present invention, which shows that the material can effectively adsorb benzene with low concentration of volatile aromatic compound for a long time. FIG. 6 is a graph of breakthrough adsorption where saturation of adsorption can be achieved in 50 hours, simulating the passage of air containing a low concentration of benzene (10ppm) through the material.