Metal organic framework material of polynuclear cobalt cluster based on two-head pyrazole ligand and application
阅读说明：本技术 基于两头吡唑配体的多核钴簇的金属有机框架材料及应用 (Metal organic framework material of polynuclear cobalt cluster based on two-head pyrazole ligand and application ) 是由 李建荣 何涛 孔祥婧 司广锐 于 2020-12-15 设计创作，主要内容包括：基于两头吡唑配体的多核钴簇的金属有机框架材料及应用,属于晶态材料的技术领域。化学分子式为[Co-8(OH)-4(OH-2)-2(BPZ-X)-6],H-2BPZ-X为芳基二(1H-吡唑),X代表芳环,X＝Pd、Pz、Pm,分别为哒嗪基、吡嗪基、嘧啶基。该类金属-有机框架的合成条件为封闭环境中,有机配体芳基二(1H-吡唑)(H-2BPZ-X)与硝酸钴在N,N-二甲基甲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；此金属-有机框架材料显示出对丙烯/丙炔混合气体的分离性能。(A multinuclear cobalt cluster metal organic framework material based on two-end pyrazole ligands and application thereof belong to the technical field of crystalline materials. Chemical formula is [ Co ] 8 (OH) 4 (OH 2 ) 2 (BPZ‑X) 6 ]，H 2 BPZ-X is aryl di (1H-pyrazole), X represents an aromatic ring, and X is Pd, Pz and Pm and is pyridazinyl, pyrazinyl and pyrimidinyl respectively. The synthesis condition of the metal-organic framework is that in a closed environment, an organic ligand aryl di (1H-pyrazole) (H) 2 BPZ-X) and cobalt nitrate in a mixed solution of N, N-dimethylformamide and water to obtain a crystal of the metal organic framework material through a solvothermal reaction; the metal-organic framework material displayThe separation performance of the propylene/propyne mixed gas is obtained.)
1. A metal-organic framework material based on two-end pyrazole ligand is characterized in that the chemical formula is [ Co ]8(OH)4(OH2)2(BPZ-X)6]，H2BPZ-X is aryl di (1H-pyrazole), X represents an aromatic ring, and X is Pd, Pz and Pm and is pyridazinyl, pyrazinyl and pyrimidinyl respectively;
H2the three internal structures of BPZ-X are as follows:
。
2. a class of metal-organic framework materials based on double pyrazole ligands according to claim 1, characterized by having the same framework structure, the crystal structure of which belongs to the cubic system from the point of view of framework connection construction, the space group being Fm-3 m.
3. A method according to claim 1Metal-organic framework materials based on two-terminal pyrazole ligands, characterized in that in the asymmetric units of the metal-organic framework crystal structure there is one crystallographically independent Co atom and 1/2 BPZ-X atoms2-A ligand; the Co atom coordinates six atoms in a double-retro-tetrahedral configuration, the coordinating atoms including three N atoms and three O atoms, wherein the three N atoms are derived from three different BPZ-X atoms2-Pyrazole group of ligand, three O atoms come from water molecule of reaction system; eight adjacent Co atoms passing through six μ4-OH/OH2Joined together to form an eight-core Co8(μ4-OH)2(μ4-OH2)4Metal cluster (Co)8O6) (ii) a Each Co8O6Cluster-connected twelve BPZ-X2-Ligands, each ligand bridging two Co8O6The metal clusters, the ligands connected alternately and the metal clusters form a three-dimensional framework.
4. A metal-organic framework material based on bipodal pyrazole ligands according to claim 1, characterized in that in the metal-organic framework the bond length of the Co-N bond is inIn the range of the bond length of Co-O bondWithin the range. Each BPZ-X2-Ligands bridge two Co8O6Cluster of each Co8O6Clusters and twelve crystallographically equivalent BPZ-X2-And (3) connecting ligands to respectively form a tetrahedral cage and an octahedral cage, and stacking the two cage-shaped structures to form a three-dimensional frame.
5. Metal-organic framework material based on bipole ligands according to claim 1, characterized in that each BPZ-X is, from a topological point of view2-The ligands can all be regarded as one-sided, twelve-coordinated Co8The Secondary Building Unit (SBU) is regarded as12-connected vertices, the two types of building blocks are alternately connected to form a classical fcu network.
6. The method for preparing a metal-organic framework material based on meta-bipyrazole ligands according to claim 1, wherein arylbis (1H-pyrazole) (H) is prepared under sealed conditions2BPZ-X) is a catalyst of cobalt nitrate (Co (NO)3)2·6H2O) obtaining crystals of the metal-organic framework via a solvothermal reaction in a mixed solution of N, N-Dimethylformamide (DMF) and deionized water; further preferred is the organic ligand arylbis (1H-pyrazole) (H)2The molar ratio of BPZ-X) to cobalt nitrate is 1 (1-4), each 0.05mmol of nickel nitrate corresponds to 1-4 mL of DMF and 0.1-4 mL of deionized water, the temperature of the thermal reaction is 100-160 ℃, and the reaction time is 12-60 hours.
7. Use of a class of metal-organic framework materials based on double-headed pyrazole ligands according to claim 1 for selective adsorptive separation of propylene/propyne mixed gases.
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 multinuclear cobalt cluster metal-organic framework material, a preparation method thereof and low-carbon hydrocarbon separation performance research.
Background
Metal-Organic Frameworks (MOFs), for short, are formed by the connection of Metal ions or Metal clusters and Organic ligands through coordination bonds. Compared with the traditional porous materials such as zeolite and activated carbon, the MOF has the characteristics of various structures, high order, good designability, easy functionalization and the like, and has wide application prospects in a plurality of research fields such as gas storage, separation, catalysis, sensing and the like.
The pore size and pore surface of MOFs can be controlled and can be used for alkane separation, and also due to chiral separation, the application in this respect is expanding. The mechanism of the MOF material for gas separation is generally based on the difference of the size, shape, polarity, polarizability and coordination ability of guest molecules, and the MOF material can produce differential adsorption to each component in the mixture. However, the existing porous materials have low adsorption selectivity to important industrial mixtures, and are still difficult to perform efficient separation and purification under mild conditions. The series of metal organic frameworks obtained by the invention can realize the separation of the propylene/propyne mixed gas under the mild condition.
Disclosure of Invention
The invention aims to provide a multinuclear cobalt cluster metal organic framework material based on two pyrazole ligands, a preparation method thereof and application of the metal organic framework material in low-carbon hydrocarbon separation performance research.
The invention relates to a metal-organic framework material of a polynuclear cobalt cluster based on two-head pyrazole ligand, and the chemical molecular formula is [ Co ]8(OH)4(OH2)2(BPZ-X)6]，H2BPZ-X is aryl di (1H-pyrazole), X represents aromatic heterocycle, X is Pd, Pz, Pm, and is pyridazinyl, pyrazinyl, pyrimidinyl respectively;
from the perspective of frame connection construction, the crystal structure of the metal-organic frame belongs to a cubic crystal system, and the space group is Fm-3 m.
The asymmetric unit of the metal-organic framework crystal structure has one crystallographically independent Co atom and 1/2 BPZ-X atoms2-A ligand. The Co atom coordinates six atoms in a double-retro-tetrahedral configuration, the coordinating atoms including three N atoms and three O atoms, wherein the three N atoms are derived from three different BPZ-X atoms2-The pyrazole group of the ligand and the three O atoms come from the water molecules of the reaction system. Eight adjacent Co atoms passing through six μ4-OH/OH2Joined together to form an eight-core Co8(μ4-OH)2(μ4-OH2)4Metal cluster (Co)8O6). Each Co8O6Cluster-connected twelve BPZ-X2-Ligands, each ligand bridging two Co8O6The metal clusters, ligands and metal clusters are alternately connected to form a three-dimensional framework.
In the metal-organic framework, the bond length of the Co-N bond is withinIn the range of the bond length of Co-O bondWithin the range. Each BPZ-X2-Ligands bridge two Co8O6Cluster of each Co8O6Clusters and twelve crystallographically equivalent BPZ-X2-And (3) connecting ligands to respectively form a tetrahedral cage and an octahedral cage, and stacking the two cage-shaped structures to form a three-dimensional frame.
From a topological perspective, each BPZ-X2-The ligands can all be regarded as one-sided, twelve-coordinated Co8Secondary Building Units (SBUs) are treated as 12-connected vertices, and the two types of building units are alternately connected to form a classical fcu network.
The synthesis method of the metal-organic framework material comprises the following steps:
aryl bis (1H-pyrazole) (H) under sealed conditions2BPZ-X) is a catalyst of cobalt nitrate (Co (NO)3)2·6H2O) in a mixed solution of N, N-Dimethylformamide (DMF) and deionized water, to obtain crystals of the metal-organic framework via a solvothermal reaction.
Further preferred is the organic ligand arylbis (1H-pyrazole) (H)2The mol ratio of BPZ-X) to cobalt nitrate is 1 (1-4), each 0.05mmol of nickel nitrate corresponds to 1-4 mL of DMF, and each 0.1-4 mL of deionized waterThe temperature of the thermal reaction is 100-160 ℃, and the reaction time is 12-60 hours.
The metal-organic framework has better chemical stability, so that the MOFs can be used for separating propylene/propyne mixed gas under the environmental condition.
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 scheme for BPZ-Pd.
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 an adsorption isotherm diagram of the metal-organic framework material on propylene and propyne.
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-Pd (0.06mmoL) and Co (NO)3)2·6H2O (0.12mmoL) was placed in a 20mL beaker, 10mL of DMF solution and 2mL of deionized water were added, the beaker was placed in an ultrasonic apparatus and sonicated at room temperature for 5 minutes, after which the solution was transferred to a 20mL Teflon reaction vessel. After sealing, the reaction kettle is placed in a 110 ℃ oven for reaction for 24 hours. After the reaction is finished, closing the oven, cooling to room temperature, opening the reaction kettle, filtering the product obtained in the reaction kettle, collecting solid particles, and sequentially using DMF (dimethyl formamide) and H (hydrogen peroxide) to obtain the product2Washed with O and EtOH (5 mL. times.3) and observed under a microscope to give yellow octahedral crystals (Co)8(OH)4(OH2)2(BPZ-Pd)6) (yield: 43% based on H2BPZ-Pd ligand).
Example 2:
weighing ligand H2BPZ-Pz (0.06mmoL) and Co (NO)3)2·6H2O (0.12mmoL) was placed in a 20mL beaker,10mL of DMF solution and 2.5mL of deionized water were added, and the beaker was placed in an sonicator and sonicated at room temperature for 5 minutes, after which the solution was transferred to a 20mL Teflon reaction kettle. After sealing, the reaction kettle is placed in an oven at 105 ℃ for reaction for 48 hours. After the reaction is finished, closing the oven, cooling to room temperature, opening the reaction kettle, filtering the product obtained in the reaction kettle, collecting solid particles, and sequentially using DMF (dimethyl formamide) and H (hydrogen peroxide) to obtain the product2Washed with O and EtOH (5 mL. times.3) and observed under a microscope to give yellow octahedral crystals (Co)8(OH)4(OH2)2(BPZ-Pz)6) (yield: 49% based on H2BPZ-Pz ligand).
Example 3
Weighing ligand H2BPZ-Pm (0.06mmoL) and Co (NO)3)2·6H2O (0.12mmoL) was placed in a 20mL beaker, 10mL of DMF solution and 0.5mL of deionized water were added, and the beaker was placed in an sonicator and sonicated at room temperature for 5 minutes, after which the solution was transferred to a 20mL Teflon reaction vessel. After sealing, the reaction kettle is placed in an oven at 120 ℃ for reaction for 48 hours. After the reaction is finished, closing the oven, cooling to room temperature, opening the reaction kettle, filtering the product obtained in the reaction kettle, collecting solid particles, and sequentially using DMF (dimethyl formamide) and H (hydrogen peroxide) to obtain the product2Washed with O and EtOH (5 mL. times.3) and observed under a microscope to give yellow octahedral crystals (Co)8(OH)4(OH2)2(BPZ-Pm)6) (yield: 37% based on H2BPZ-Pm ligand).
Example 4
Weighing ligand H2BPZ-Pm (0.04mmoL) and Co (NO)3)2·6H2O (0.1mmoL) was placed in a 20mL beaker, 8mL of DMF solution and 0.3mL of deionized water were added, and the beaker was placed in an ultrasonic apparatus and sonicated at room temperature for 5 minutes, after which the solution was transferred to a 20mL Teflon reaction vessel. After sealing, the reaction kettle is placed in an oven at 130 ℃ for reaction for 48 hours. After the reaction is finished, closing the oven, cooling to room temperature, opening the reaction kettle, filtering the product obtained in the reaction kettle, collecting solid particles, and sequentially using DMF (dimethyl formamide) and H (hydrogen peroxide) to obtain the product2O and EtOH washes (5 mL. times.3),observing under a microscope to obtain yellow octahedral crystal (Co)8(OH)4(OH2)2(BPZ-Pm)6) (yield: 47% based on H2BPZ-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 used for constructing such metal-organic frameworks.
FIG. 2 shows two-terminal pyrazole ligands H for synthesizing the metal-organic framework2The BPZ-X (X ═ Pd, Pz, Pm) roadmap indicates: firstly, dibromoaryl and tetrahydropyrane protected pyrazole boric acid ester 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 bis (1- (tetrahydro-2H-pyran-2-yl) -1H-pyrazole-4-yl) aryl; then bis (1- (tetrahydro-2H-pyran-2-yl)Heating the-1H-pyrazol-4-yl) aryl in a hydrochloric acid ethanol solution to remove protection to obtain the bis (1H-pyrazol-4-yl) aryl.
FIG. 3 is a diagram of the inorganic building blocks of the metal-organic framework showing: the inorganic node contained in the frame structure is cubic Co8(μ4-OH)(μ4-OH2) A metal cluster.
Fig. 4 is a schematic three-dimensional structure of the metal-organic framework showing: the framework structure comprises octahedral and tetrahedral cages.
(2) Characterization of adsorption properties of low-carbon hydrocarbon compounds
Fig. 5 is an adsorption isotherm diagram of the metal-organic framework material on propylene and propyne, and it can be seen that the material has obvious difference in adsorption behaviors on propylene and propyne, and can be used for adsorption separation of propylene/propyne mixed gas. FIG. 5 is an adsorption isotherm of propylene and propyne in a thermostatic waterbath at 298K for the material of the present invention, as tested by a gas adsorber.
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