阅读说明：本技术 三维共价有机框架化合物及其制备方法 (Three-dimensional covalent organic framework compound and preparation method thereof ) 是由 吴晓伟 单震 张根 于 2021-10-12 设计创作，主要内容包括：本发明公开了一种三维共价有机框架化合物及其制备方法。所述的三维共价有机框架化合物由卟啉类八价基团与苯类二价基团通过基团连接形成,每个卟啉类八价基团与其相邻的八个苯类二价基团连接,每个苯类二价基团化合物与相邻的两个卟啉类八价基团连接,以此构成含有动态共价键的bcu三维拓扑网络结构。本发明的三维共价有机框架化合物中含有卟啉单元,与金属配位后在光解水产氢等催化领域有较好的应用前景。(The invention discloses a three-dimensional covalent organic framework compound and a preparation method thereof. The three-dimensional covalent organic framework compound is formed by connecting porphyrin octavalent groups and benzene bivalent groups through groups, each porphyrin octavalent group is connected with eight benzene bivalent groups adjacent to the porphyrin octavalent group, and each benzene bivalent group compound is connected with two adjacent porphyrin octavalent groups, so that an bcu three-dimensional topological network structure containing dynamic covalent bonds is formed. The three-dimensional covalent organic framework compound contains porphyrin units, and has good application prospect in the catalysis field of photolysis of water to produce hydrogen and the like after coordination with metal.)

1. The three-dimensional covalent organic framework compound is characterized in that the structural general formula is shown as formula (1):

2. the method of preparing a three-dimensional covalent organic framework compound according to claim 1, comprising the steps of:

step 1, adding 1, 3-dibromobenzaldehyde into a three-necked bottle, adding propionic acid, dripping pyrrole under a reflux state, carrying out reflux reaction, cooling to room temperature after complete reaction, adding hot water for washing, and carrying out suction filtration to obtain a porphyrin octabromo compound;

step 2, adding anhydrous potassium carbonate, tetratriphenylphosphine palladium, porphyrin octabromode compounds and 4-formylphenylboronic acid into a mixed solution of tetrahydrofuran and water, uniformly mixing, carrying out reflux stirring reaction on a mixture formed in a nitrogen atmosphere, cooling to room temperature after complete reaction, removing an organic solvent under reduced pressure, extracting with dichloromethane, drying with anhydrous sodium sulfate, removing the solvent to obtain a crude product, purifying the crude product by chromatography, eluting with dichloromethane to obtain the porphyrin octaaldehydic compounds with the structural formula shown in the formula (2),

step 3, mixing porphyrin octaldehyde compound, benzene divalent compound and organic solvent, then freezing by liquid nitrogen, vacuumizing and sealing, wherein the structural formula of the benzene divalent compound is shown as the formula (3):

and 4, heating the mixture obtained in the step 3 at 90-150 ℃ for reaction, cooling to room temperature after the reaction is finished, filtering out precipitates, soaking in an organic solvent, and drying in vacuum to obtain the three-dimensional covalent organic framework compound.

3. The method according to claim 2, wherein in step 3, the molar ratio of the porphyrin octaldehyde compound to the benzene divalent compound is 1: 4.

4. The method according to claim 2, wherein in step 3, the organic solvent is selected from the group consisting of mesitylene, a mixture of dioxane and acetic acid solution, and a mixture of ortho-dichlorobenzene, n-butanol and acetic acid solution; the concentration of the acetic acid solution is 9M.

5. The method according to claim 2, wherein in the step 3, when the organic solvent is a mixture of mesitylene, dioxane and acetic acid solution, the volume ratio of mesitylene, dioxane and acetic acid solution is (5-15): 5-10): 1-5.

6. The method according to claim 5, wherein the volume ratio of the mesitylene to the dioxane to the acetic acid solution is 10:10: 3.

7. The method according to claim 2, wherein in the step 3, when the organic solvent is a mixture of o-dichlorobenzene, n-butanol and acetic acid solution, the volume ratio of o-dichlorobenzene, n-butanol and acetic acid solution is (10-20): 1-10): 1-5.

8. The method according to claim 7, wherein the volume ratio of the o-dichlorobenzene, the n-butanol and the acetic acid solution is 15:5: 2.

9. The method according to claim 2, wherein the reaction temperature in step 4 is 120 ℃.

10. The method according to claim 2, wherein the reaction temperature in step 4 is 72 to 96 hours.

Technical Field

The invention belongs to the field of covalent organic framework materials, and relates to a three-dimensional covalent organic framework compound and a preparation method thereof.

Background

Covalent organic framework materials (COFs) are periodically ordered crystalline porous polymers formed by organic units through dynamic covalent bond connection, have the characteristics of low density, permanent porosity, high specific surface area, relatively high thermal stability and the like, and can form framework structures with different topologies by changing the geometric structures of the constructed organic units. In terms of the dimensions of the structure, COF materials can be divided into two-dimensional (2D) COF and three-dimensional (3D) COF covalent organic framework materials. For 2D COFs, it is common to build up a layered structure from one or more planar building blocks and form a periodic two-dimensional structure by stacking layers. In the case of 3D COF, the building units have a three-dimensional structure, and are connected to each other in three dimensions by dynamic covalent bonds to form a three-dimensional network structure.

Different topological structures form different pore channel structures, so that the synthesis of the three-dimensional covalent organic framework material is very important. At present, three-dimensional topological structures are limited to acs, ctn, bor, dia, pts, rra, srs, ceq, soc, ffc, fjh, ljh, pcu, tbo and lon, and building modules of the topological structures are limited to trivalent, quadrivalent and hexavalent states, so that the design of a three-dimensional covalent organic framework material for synthesizing a novel topological structure connected with a high valence state is still an important research direction.

Disclosure of Invention

The invention provides a three-dimensional covalent organic framework compound, which has a structural general formula shown in a formula (1):

the porphyrin octaaldehyde compound with 8 connecting end groups and the benzene divalent compound with 2 connecting end groups are connected in a three-dimensional space through covalent bonds. At least one part of the three-dimensional covalent organic framework compound is characterized in that each porphyrin-like octavalent group is connected with eight benzene-like bivalent groups adjacent to the porphyrin-like octavalent group, and each benzene-like bivalent group compound is connected with two adjacent porphyrin-like octavalent groups, so that an bcu three-dimensional topological network structure containing dynamic covalent bonds is formed.

The structural formula of the porphyrin octa-aldehyde compound is shown as a formula (2):

the structural formula of the benzene divalent compound is shown as the formula (3):

the invention also provides a preparation method of the three-dimensional covalent organic framework compound, which comprises the following steps:

step 1, adding 1, 3-dibromobenzaldehyde into a three-necked bottle, adding propionic acid, dripping pyrrole under a reflux state, carrying out reflux reaction, cooling to room temperature after complete reaction, adding hot water for washing, and carrying out suction filtration to obtain a porphyrin octabromo compound;

step 2, adding anhydrous potassium carbonate, tetratriphenylphosphine palladium, a porphyrin octabromo compound and 4-formylphenylboronic acid into a mixed solution of tetrahydrofuran and water, uniformly mixing, carrying out reflux stirring reaction on a mixture formed in a nitrogen atmosphere, cooling to room temperature after complete reaction, removing an organic solvent under reduced pressure, extracting with dichloromethane, drying with anhydrous sodium sulfate, removing the solvent to obtain a crude product, purifying the crude product by chromatography, and eluting with dichloromethane to obtain the porphyrin octaformyl compound (TTEP);

step 3, mixing porphyrin octa-aldehyde compounds, benzene divalent compounds and an organic solvent, freezing by liquid nitrogen, and vacuumizing and sealing;

and 4, heating the mixture obtained in the step 3 at 90-150 ℃ for reaction, cooling to room temperature after the reaction is finished, filtering out precipitates, soaking in an organic solvent, and drying in vacuum to obtain the three-dimensional covalent organic framework compound.

Preferably, in the step 3, the molar ratio of the porphyrin octaaldehyde compound to the benzene divalent compound is 1: 4.

Preferably, in step 3, the organic solvent is selected from a mixture of mesitylene, dioxane and acetic acid solution, or a mixture of ortho-dichlorobenzene, n-butanol and acetic acid solution. The concentration of the acetic acid solution is 9M.

Preferably, in the step 3, when the organic solvent is a mixture of mesitylene, dioxane and an acetic acid solution, the volume ratio of mesitylene, dioxane and acetic acid solution is (5-15): 5-10): 1-5, and more preferably 10:10: 3.

Preferably, in the step 3, when the organic solvent is a mixture of o-dichlorobenzene, n-butanol and an acetic acid solution, the volume ratio of the o-dichlorobenzene, the n-butanol and the acetic acid solution is (10-20): (1-10): 1-5), and more preferably 15:5: 2.

Preferably, in step 4, the reaction temperature is 120 ℃.

Preferably, in the step 4, the reaction temperature is 72-96 hours.

Compared with the prior art, the invention has the following advantages:

the invention designs and synthesizes porphyrin octaaldehyde compound for the first time, and prepares bcu three-dimensional topological network structure three-dimensional covalent organic framework compound containing dynamic covalent bond by a hydrothermal method. In the compound, each porphyrin octavalent group is connected with eight adjacent benzene bivalent groups, and each benzene bivalent group compound is connected with two adjacent porphyrin octavalent groups. The three-dimensional covalent organic framework compound contains porphyrin units, and has good application prospects in the field of catalysis after coordination with metals, such as photolysis of water to produce hydrogen, reduction of carbon dioxide and the like.

Drawings

FIG. 1 is a schematic of the synthetic route for three-dimensional covalent organic framework compounds.

FIG. 2 is a PXRD pattern of the three-dimensional covalent organic framework compound 3D-bcu-COF-1, TTEP, PDA.

FIG. 3 is a PXRD pattern of the three-dimensional covalent organic framework compound 3D-bcu-COF-2, TTEP, PDA-Me.

FIG. 4 shows the IR spectra of the three-dimensional covalent organic framework compound 3D-bcu-COF-1, TTEP, PDA.

FIG. 5 is an IR spectrum of the three-dimensional covalent organic framework compound 3D-bcu-COF-2, TTEP, PDA-Me.

FIG. 6 is a scanning electron micrograph of the three-dimensional covalent organic framework compound 3D-bcu-COF-1.

FIG. 7 is a scanning electron micrograph of the three-dimensional covalent organic framework compound 3D-bcu-COF-2.

FIG. 8 is a transmission electron micrograph of the three-dimensional covalent organic framework compound 3D-bcu-COF-1.

FIG. 9 is a transmission electron micrograph of the three-dimensional covalent organic framework compound 3D-bcu-COF-2.

FIG. 10 is a nitrogen adsorption-desorption curve of the three-dimensional covalent organic framework compound 3D-bcu-COF-1 at 77K.

FIG. 11 is a graph of pore size distribution for the three-dimensional covalent organic framework compound 3D-bcu-COF-1.

FIG. 12 is a nitrogen adsorption-desorption curve of the three-dimensional covalent organic framework compound 3D-bcu-COF-2 at 77K.

FIG. 13 is a graph of pore size distribution for the three-dimensional covalent organic framework compound 3D-bcu-COF-2.

Detailed Description

The present invention will be described in more detail with reference to the following examples and the accompanying drawings.

Example 1

A method for preparing a three-dimensional covalent organic framework compound (3D-bcu-COF-1, 3D-bcu-COF-2) comprising the steps of:

(1) synthesis of porphyrin octabromide compound:

adding 1, 3-dibromobenzaldehyde (2.64g) into a 250mL three-necked bottle, adding 150mL propionic acid, and heating to reflux under stirring; thereafter, pyrrole (0.7mL) was added dropwise under reflux. After the dropwise addition, the mixture was refluxed for 4 hours. After the reaction is finished, cooling to room temperature, adding hot water for washing, performing suction filtration to obtain a purple crude product porphyrin octabromide compound, and directly using the purple crude product porphyrin octabromide compound for the next reaction after vacuum drying.

(2) Synthesis of porphyrin octaaldehyde compound (TTEP):

anhydrous potassium carbonate (13.3g) and tetrakistriphenylphosphine palladium (1.2g) were added to a mixed solution of porphyrin octabromide compound (5.0g) and 4-formylphenylboronic acid (8.8g) in tetrahydrofuran and water (300mL, v/v ═ 3/1); the compound was stirred at reflux under nitrogen atmosphere for two days. The mixture was cooled to room temperature and the organic solvent was removed under reduced pressure; extraction with dichloromethane, drying over anhydrous sodium sulfate and removal of the solvent under reduced pressure gave the crude product. The crude product is purified by chromatography, eluent dichloromethane. 4.64g of porphyrin octaldehyde compound (TTEP) was obtained with a yield of 80%.

(3) Synthesis of 3D-bcu-COF-1.

Porphyrin octa-aldehyde compound monomer (36.2mg) and p-phenylenediamine (PDA, 10.8mg) were placed in a heat-resistant glass tube, and a mixture of 1: 1 (2mL) of a mixed solution of mesitylene and dioxane, and uniformly mixed by ultrasonic treatment. A9M acetic acid solution (0.3mL) was added to the glass tube, which was then rapidly frozen with liquid nitrogen (77K), evacuated, and flame sealed under vacuum. And (3) placing the sealed glass tube in a 120 ℃ oven to react for 72 hours to obtain a brown precipitate. After the reaction is finished, cooling to room temperature, filtering to separate solid, and soaking the solid product in methanol (20mL) and acetone (20mL) for three times respectively; the solid product was suction filtered off and then dried in vacuo to give 3D-bcu-COF-1(37.6mg, 80% yield).

(4) Synthesis of 3D-bcu-COF-2.

Porphyrin octa-aldehyde compound monomer (36.2mg) and 2, 5-dimethyl p-phenylenediamine (PDA-Me, 13.6mg) were placed in a heat-resistant glass tube, and the volume ratio was 3: 1 (2mL) of a mixed solution of o-dichlorobenzene and n-butanol, and performing ultrasonic treatment to uniformly mix the solution. A9M acetic acid solution (0.3mL) was added to the glass tube, which was then rapidly frozen with liquid nitrogen (77K), evacuated, and flame sealed under vacuum. And (3) placing the sealed glass tube in a 120 ℃ oven to react for 72 hours to obtain a brown precipitate. After the reaction is finished, cooling to room temperature, filtering to separate solid, and soaking the solid product in methanol (20mL) and acetone (20mL) for three times respectively; the solid product was suction filtered off and then dried in vacuo to give 3D-bcu-COF-2(39.4mg, 80% yield).

(5) Product characterization

FIG. 2 shows PXRD patterns of monomers required for synthesis and a product 3D-bcu-COF-1, and the successful synthesis of a novel three-dimensional covalent organic framework compound by the method can be confirmed by the appearance of peaks at 3.33,4.60,6.72 and 10.26 degrees from PXRD.

FIG. 3 shows PXRD patterns of monomers required for synthesis and a product 3D-bcu-COF-2, and the successful synthesis of a novel three-dimensional covalent organic framework compound by the method can be confirmed by the fact that peaks appear at 3.18,4.50,6.46 and 9.88 degrees according to PXRD.

FIG. 4 shows the IR spectrum of the desired monomer synthesis and the product 3D-bcu-COF-1, from which the synthesized three-dimensional covalent organic framework compound was seen at 1621cm^-1There was a peak indicating the formation of-C ═ N.

FIG. 5 shows the IR spectrum of the desired monomer synthesis and the product 3D-bcu-COF-2, from which the synthesized three-dimensional covalent organic framework compound was seen at 1622cm^-1There was a peak indicating the formation of-C ═ N.

FIG. 6 shows the scanning electron micrograph of the product 3D-bcu-COF-1, showing the lamellar structure of the material.

FIG. 7 shows the scanning electron micrograph of the product 3D-bcu-COF-2, showing the lamellar structure of the material.

FIG. 8 shows transmission electron micrographs of the product 3D-bcu-COF-1, showing the lamellar structure of the material, consistent with scanning electron microscopy.

FIG. 9 shows transmission electron micrographs of the product 3D-bcu-COF-2, showing the lamellar structure of the material, consistent with scanning electron microscopy.

FIG. 10 shows nitrogen adsorption desorption curves of a three-dimensional covalent organic framework compound 3D-bcu-COF-1 having a BET specific surface area of 181.2m² g^-1。

FIG. 11 shows a distribution of pore sizes of the three-dimensional covalent organic framework compound 3D-bcu-COF-1, with a pore size of 1.75 nm.

FIG. 12 shows the nitrogen adsorption desorption curve of the three-dimensional covalent organic framework compound 3D-bcu-COF-2, which has a BET specific surface area of 93.4m² g^-1。

FIG. 13 shows a distribution of pore sizes of the three-dimensional covalent organic framework compound 3D-bcu-COF-2, with a pore size of 1.73 nm.