Preparation method of single-crystal vinyl bridged covalent organic framework material

Abstract

The invention belongs to the technical field of covalent organic framework materials, and particularly relates to a preparation method of a single-crystal vinyl bridged covalent organic framework material. The preparation method of the single-crystal vinyl-bridged covalent organic framework material comprises the following steps: uniformly mixing a single-crystal imino covalent organic framework material, an active monomer, a catalyst and an organic solvent, and then carrying out substitution reaction, the substitution reaction is one or more of aldol condensation reaction, Knoevenagel condensation reaction and Claisen-Schmidt reaction. The single crystal vinyl bridged covalent organic framework material which is good in stability, rich in active sites, high in photoelectric activity and high in conjugation degree is obtained through substitution reaction of a single crystal imino covalent organic framework material and an active monomer under the action of a catalyst, and excellent conductivity and room-temperature ferromagnetism are shown.

Description

Technical Field

[0001] The invention belongs to the technical field of covalent organic framework materials, and particularly relates to a method for preparing a single-crystal vinyl-bridged covalent organic framework material. Background Art

[0002] Covalent organic frameworks (COFs) are porous crystalline frameworks with a two-dimensional topology formed by covalently linked π-conjugated building blocks. Their uniform pore size gives them the name "organic zeolites." They possess advantageous properties such as high crystallinity, large surface area, high electrical conductivity, high porosity, low skeleton density, and high thermochemical stability. They hold broad application prospects in organic electronics, gas storage and separation, biomedicine, catalytic chemical engineering, desalination, fluorescence sensing, optoelectronic materials, and energy storage.

[0003] Among them, vinyl-bridged covalent organic framework materials (sp 2 C-COFs) are a class of 2 Carbon-connected organic porous materials have the characteristics of high conjugation, excellent carrier transport properties, high chemical and thermal stability, regular structure, strong designability and easy functionalization. They are widely used in the new generation of organic semiconductor devices, energy conversion and storage, sensing, gas adsorption and separation.

[0004] However, the vinyl bridged covalent organic framework materials synthesized by existing technologies are all polycrystalline or amorphous structures. 2 The main difficulty in preparing c-COFs lies in the excellent chemical stability of the vinyl bond, which causes the covalent organic framework material constructed based on reversible dynamic chemistry to lose the self-repairing ability of the crystal. During the polymerization reaction, the stable vinyl connection mode makes the kinetically driven polymerization process dominant. On the contrary, the crystal self-repair process driven by thermodynamics is constrained by the connection mode of strong covalent bonds, making it difficult to perform dynamic chemical self-repair of the crystal, resulting in the prepared covalent organic framework material being partially ordered or completely disordered, causing structural defects and reduced performance. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a single-crystalline vinyl bridged covalent organic framework material in order to solve the problem that the traditional polymerization method is not reversible enough, resulting in the vinyl COFs being polycrystalline or amorphous. The single-crystalline vinyl bridged covalent organic framework material (sc-sp) with excellent electrical conductivity and room temperature ferromagnetism can be obtained. 2 c-COF).

[0006] The preparation method of the single crystal vinyl bridged covalent organic framework material in the technical solution of the present invention comprises uniformly mixing the single crystal imine-based covalent organic framework material, an active monomer, a catalyst and an organic solvent and then performing a substitution reaction.

[0007] Single-crystal imine-based covalent organic framework materials can arrange and assemble active monomers in three-dimensional space, thereby avoiding the kinetic traps in the direct formation of stable carbon-carbon double bonds in traditional polymerization methods; at the same time, the imine bond has poor stability, and during the single crystal transformation process, the imine-based monomers can be gradually replaced by active monomers to achieve the synthesis of single-crystal vinyl covalent organic frameworks. The resulting single-crystal vinyl-bridged covalent organic framework material has a long-range ordered crystal structure, good stability, rich active sites, high photoelectric activity, and high conjugation degree. It has excellent photoelectric activity and stability, and exhibits good conductivity and room-temperature ferromagnetism.

[0008] Furthermore, the molar ratio of the active monomer to the smallest fragment of the single crystal imine-based covalent organic framework material is 3.0:0.1-1.0.

[0009] Furthermore, the substitution reaction is one or more of an aldol condensation reaction, a Knoevenagel condensation reaction, and a Claisen-Schmidt reaction.

[0010] Furthermore, when the substitution reaction is an aldol condensation reaction, the active monomer is one or two of an azine-type methyl monomer and an azole-type methyl monomer, including but not limited to 3,6-dimethylpyridazine, 2,3,5,6-tetramethylpyrazine, 2,2',6,6'-tetramethyl-4,4'-bipyridine, 4,7-dimethyl-[1,2,5]oxadiazolo[3,4-c]pyridine, 2,6-dimethylbenzo[1,2-d:4,5-d']bis(thiazole), 2,6-dimethylbenzo[1,2-d :5,4-d']bis(thiazole), 2,6-dimethylbenzo[1,2-d:4,5-d']bisoxazole, 5,10,15,20-tetrakis(2-methylpyrimidin-5-yl)porphyrin, 5,5',5",5"'-(1,10-dihydroperene-2,5,8,11-tetrakis(2-methylpyrimidine), 2,3,6,7,10,11-hexa(2-methylpyrimidin-5-yl)dipyrazino[2,3-f:2',3'-h]quinoxaline or one or more thereof.

[0011] Furthermore, when the substitution reaction is a Knoevenagel condensation reaction, the active monomer is a cyano-substituted methylene monomer, including but not limited to terephthalonitrile, 2,2'-(perfluoro-1,4-phenylene)diacetonitrile, 2,2'-([1,1'-biphenyl]-4,4'-diyl)diacetonitrile, 2,2',2"-((1,3,5-triazine-2,4,6-triyl)tris(phenyl-4,1-diyl))triacetonitrile, 2 , one or more of 2',2",2"'-(porphyrin-5,10,15,20-tetrayltetra(benzene-4,1-diyl))tetraacetonitrile, 2,2',2",2"'-(pyrene-1,3,6,8-tetrayltetra(benzene-4,1-diyl))tetraacetonitrile, and 2,2',2",2"'-((1,10-dihydroperene-2,5,8,11-tetrayl)tetra(benzene-4,1-diyl))tetraacetonitrile.

[0012] Furthermore, when the substitution reaction is a Claisen-Schmidt reaction, the active monomer is an acetylphenyl monomer, including but not limited to one or more of 1,1'-(1,4-phenylene)bis(ethane-1-one); 1,1'-(perfluoro-[1,1'-biphenyl]-4,4'-diyl)bis(ethane-1-one); 1,1'-(acetylene-1,2-diylbis(4,1-phenylene))bis(ethane-1-one); 1,1',1"-((1,3,5-triazine-2,4,6-triyl)tri(benzene-4,1-diyl))tri(ethane-1-one); and 1,1',1"-((benzene-1,3,5-tri(acetylene-2,1-diyl))tri(benzene-4,1-diyl))tri(ethane-1-one).

[0013] Furthermore, the catalyst is one or more of benzoic acid, benzoic anhydride, p-toluenesulfonic acid, trifluoroacetic acid, acetic acid, p-toluic anhydride, p-fluorobenzoic acid, phthalic acid, terephthalic acid, trimesic acid, pyromellitic acid, p-toluenesulfonic acid, m-toluic acid, cesium carbonate, sodium hydroxide, potassium hydroxide, and 1,8-diazabicycloundec-7-ene.

[0014] Preferably, the mass of the catalyst is 1.0-5.0% of the mass of the imine-based covalent organic framework material.

[0015] Furthermore, the organic solvent is one or more of o-dichlorobenzene, n-butanol, toluene, mesitylene, n-butanol, 1,4-dioxane, and benzoic anhydride.

[0016] Preferably, 0.1 to 0.5 ml of organic solvent is added to 1 mg of the imine-based covalent organic framework material.

[0017] Furthermore, in the method for preparing the single crystal vinyl-bridged covalent organic framework material, the components are mixed and then vacuumed and filled with nitrogen, and the operation is repeated 3 to 10 times.

[0018] Furthermore, the temperature of the substitution reaction is 80-200° C., and the time is 3-15 days.

[0019] Preferably, the product obtained after the substitution reaction is washed with acetone and tetrahydrofuran solvents in sequence, and then vacuum dried.

[0020] The present invention also provides a single crystal vinyl bridged covalent organic framework material, which is prepared by the above-mentioned preparation method of the single crystal vinyl bridged covalent organic framework material.

[0021] Furthermore, the specific surface area of ​​the single-crystalline vinyl-bridged covalent organic framework material is 100 to 2000 m 2 / g, and the pore size distribution is 0.5~4.0nm.

[0022] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0023] (1) Through the substitution reaction of single-crystal imine-based covalent organic framework materials and active monomers under the action of catalysts, single-crystal vinyl-bridged covalent organic framework materials with good stability, rich active sites, high photoelectric activity, and high conjugation degree are obtained, which show excellent electrical conductivity and room-temperature ferromagnetism;

[0024] (2) Single-crystal imine-based covalent organic frameworks can arrange and assemble active monomers in three-dimensional space, thereby avoiding the kinetic traps in the process of directly forming stable carbon-carbon double bonds in traditional polymerization methods, and solving the problem of insufficient reversibility of traditional polymerization methods that leads to polycrystalline or amorphous vinyl COFs;

[0025] (3) The imine bond in the single-crystal imine-based covalent organic framework material is relatively unstable. During the single-crystal transformation process, the imine monomer can be gradually replaced by an active monomer, thus achieving the efficient synthesis of a single-crystal vinyl-bridged covalent organic framework.

[0026] (4) The method for preparing the single-crystalline vinyl-bridged covalent organic framework material uses the single-crystalline imine-based covalent organic framework material as a template and does not require a large amount of solvent system for preparation, and can quickly prepare the target single-crystalline vinyl-bridged covalent organic framework material. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the preparation method of the single crystal vinyl bridged covalent organic framework material of the present invention;

[0028] Figure 2 The single crystal vinyl bridged covalent organic framework material sc-sp obtained in Example 1 2 Infrared spectra of c-COF-1 and single-crystalline imine-based covalent organic framework material COF-303;

[0029] Figure 3 The single crystal vinyl bridged covalent organic framework material sc-sp obtained in Example 1 2 Raman spectra of c-COF-1 and single-crystalline imine-based covalent organic framework material COF-303;

[0030] Figure 4 The single crystal vinyl bridged covalent organic framework material sc-sp obtained in Example 1 2 X-ray diffraction pattern of c-COF-1;

[0031] Figure 5 The single crystal vinyl bridged covalent organic framework material sc-sp obtained in Example 1 2 Solid-state NMR carbon spectra of c-COF-1 and single-crystalline imine-based covalent organic framework material COF-303;

[0032] Figure 6 The single crystal vinyl bridged covalent organic framework material sc-sp obtained in Example 1 2 Optical images of c-COF-1 and single-crystalline imine-based covalent organic framework material COF-303;

[0033] Figure 7 Example 1 Single crystal vinyl bridged covalent organic framework material sc-sp 2 Magnetic properties of c-COF-1 and single-crystalline imine-based covalent organic framework material COF-303;

[0034] Figure 8 The single crystal vinyl bridged covalent organic framework material sc-sp obtained in Example 2 and Example 3 2 c-COF-2 and sc-sp 2 X-ray diffraction spectrum of c-COF-3. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be further described below by means of specific examples and accompanying drawings. It should be understood that the specific embodiments described herein are only used to help understand the present invention and are not intended to be limiting of the present invention. The accompanying drawings used herein are only for the purpose of better illustrating the present invention and do not limit the scope of protection. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used raw materials in the art, and the methods used in the embodiments are all conventional methods in the art.

[0036] The preparation method of the single-crystalline imine-based covalent organic framework material used in the following examples refers to the preparation process of Example 1 in Chinese patent CN106083909A.

[0037] Example 1

[0038] The preparation method of the single-crystalline vinyl-bridged covalent organic framework material in this embodiment includes adding a single-crystalline imine-based covalent organic framework material (COF-303, 8 mg), 2,5-dimethylpyrazine, trifluoroacetic acid (180 μL), mesitylene (0.5 ml) and 1,4-dioxane (0.5 ml) into a quartz glass tube and mixing them evenly. The molar ratio of 2,5-dimethylpyrazine to the single-crystalline imine-based covalent organic framework material is 3.0:0.5. The mixed reaction system is evacuated and filled with nitrogen for 3 cycles and then sealed. The system is heated at 120° C. for 3 days. After the reaction is completed, the product is washed with acetone and tetrahydrofuran solvents in sequence and dried in vacuo to obtain sc-sp 2 c-COF-1.

[0039] The obtained sc-sp 2 The infrared spectroscopy characterization results of c-COF-1 are as follows Figure 2 As shown, 1658cm -1 The infrared vibration peak at indicates the formation of carbon-carbon double bond; Raman spectroscopy characterization results are as follows Figure 3 As shown, it can also be seen that a carbon-carbon double bond is formed; the X-ray diffraction pattern is as follows Figure 4 As shown, it can be seen that the material has good crystallinity; the optical picture ( Figure 6 ) shows that after single crystal conversion sc-sp 2 c-COF-1 still maintains a single crystal morphology; sc-sp 2 The solid-state NMR spectra of c-COF-1 and imine COF-303 are as follows Figure 5 As shown in the figure, after the single crystal conversion, the carbon signal on the imine at 158 ​​ppm disappears, and a new carbon-carbon double bond signal is generated at 128, indicating that the single crystal imine-based covalent organic framework material is completely transformed from the chemical structure to the single crystal vinyl-bridged covalent organic framework material; Figure 7 Display the resulting sc-sp 2 The magnetic intensity of c-COF-1 is 8.04×10 -2 emug -1 , showing good room-temperature ferromagnetism.

[0040] Example 2

[0041] The preparation method of the single-crystalline vinyl-bridged covalent organic framework material in this embodiment includes adding a single-crystalline imine-based covalent organic framework material (COF-303, 8 mg), 3,6-dimethylpyridazine, trifluoroacetic acid (180 μL), mesitylene (0.5 ml) and 1,4-dioxane (0.5 ml) into a quartz glass tube and mixing them evenly. The molar ratio of 3,6-dimethylpyridazine to the single-crystalline imine-based covalent organic framework material is 3.0:0.8. The mixed reaction system is evacuated and filled with nitrogen, and the cycle is repeated three times before sealing. The system is heated at 150° C. for three days. After the reaction is completed, the product is washed with acetone and tetrahydrofuran solvents in sequence and dried in vacuo to obtain sc-sp 2 c-COF-2, such as Figure 8 As shown, it can be seen that the material has good crystallinity.

[0042] Example 3

[0043] The preparation method of the single-crystalline vinyl-bridged covalent organic framework material in this embodiment includes adding a single-crystalline imine-based covalent organic framework material (COF-303, 8 mg), 3,6-dimethyl-1,2,4,5-tetrazine, trifluoroacetic acid (180 μL), mesitylene (0.5 ml) and 1,4-dioxane (0.5 ml) into a quartz glass tube and mixing them evenly. The molar ratio of 3,6-dimethyl-1,2,4,5-tetrazine to the single-crystalline imine-based covalent organic framework material is 3.0:0.5. The mixed reaction system is evacuated and filled with nitrogen for 3 cycles and then sealed. The mixture is heated at 100° C. for 5 days. After the reaction is completed, the product is washed with acetone and tetrahydrofuran solvents in sequence and dried in vacuo to obtain sc-sp 2 c-COF-3, such as Figure 8 As shown, it can be seen that the material has good crystallinity.

[0044] Example 4

[0045] The preparation method of the single-crystalline vinyl-bridged covalent organic framework material in this embodiment includes adding a single-crystalline imine-based covalent organic framework material (COF-303, 8 mg), 1,1'-(1,4-phenylene)bis(ethan-1-one), cesium carbonate (0.1 mL, 1M aqueous solution) and dimethylacetamide (1 mL) into a quartz glass tube and mixing them evenly. The molar ratio of 1,1'-(1,4-phenylene)bis(ethan-1-one) to the single-crystalline imine-based covalent organic framework material is 3.0:0.5. The mixed reaction system is evacuated and filled with nitrogen, and the cycle is repeated four times before sealing. The system is heated at 120° C. for three days. After the reaction is completed, the product is washed with acetone and tetrahydrofuran solvents in sequence, and vacuum dried to obtain sc-sp 2 c-COF-4.

[0046] Example 5

[0047] The preparation method of the single-crystalline vinyl-bridged covalent organic framework material in this embodiment includes adding a single-crystalline imine-based covalent organic framework material (COF-303, 8 mg), 1,1'-(2,3,5,6-tetramethyl-1,4-phenylene)bisethane-1-one, cesium carbonate (0.1 mL, 1M aqueous solution) and dimethylacetamide (1 mL) into a quartz glass tube and mixing them evenly. The molar ratio of 1,1'-(2,3,5,6-tetramethyl-1,4-phenylene)bisethane-1-one to the single-crystalline imine-based covalent organic framework material is 3.0:0.5. The mixed reaction system is evacuated and filled with nitrogen, and the cycle is repeated three times before sealing. The system is heated at 120° C. for three days. After the reaction is completed, the product is washed with acetone and tetrahydrofuran solvents in sequence, and vacuum dried to obtain sc-sp 2 c-COF-5.

[0048] Example 6

[0049] The preparation method of the single-crystalline vinyl-bridged covalent organic framework material in this embodiment includes adding a single-crystalline imine-based covalent organic framework material (COF-303, 8 mg), terephthalonitrile, cesium carbonate (0.1 mL, 1 M aqueous solution) and dimethylacetamide (1 mL) into a quartz glass tube and mixing them evenly. The molar ratio of terephthalonitrile to the single-crystalline imine-based covalent organic framework material is 3.0:0.6. The mixed reaction system is evacuated and filled with nitrogen. After three cycles, it is sealed and heated at 180°C for 3 days. After the reaction is completed, the product is washed with acetone and tetrahydrofuran solvents in sequence, and vacuum dried to obtain sc-sp 2 c-COF-6.

[0050] Example 7

[0051] The preparation method of the single-crystalline vinyl-bridged covalent organic framework material in this embodiment includes adding a single-crystalline imine-based covalent organic framework material (COF-303, 8 mg), [1,1'-biphenyl]-4,4'-dicarbonitrile, cesium carbonate (0.1 mL, 1M aqueous solution) and dimethylacetamide (1 mL) into a quartz glass tube and mixing them evenly. The molar ratio of [1,1'-biphenyl]-4,4'-dicarbonitrile to the single-crystalline imine-based covalent organic framework material is 3.0:1.0. The mixed reaction system is evacuated and filled with nitrogen for 3 cycles and then sealed. The system is heated at 120°C for 3 days. After the reaction is completed, the product is washed with acetone and tetrahydrofuran solvents in sequence and dried in vacuo to obtain sc-sp 2 c-COF-7.

[0052] Example 8

[0053] The preparation method of the single-crystalline vinyl-bridged covalent organic framework material in this embodiment includes adding a single-crystalline imine-based covalent organic framework material (COF-303, 8 mg), 2,3,5,6-tetramethylterephthalonitrile, cesium carbonate (0.1 mL, 1 M aqueous solution) and dimethylacetamide (1 mL) into a quartz glass tube and mixing them evenly. The molar ratio of 2,3,5,6-tetramethylterephthalonitrile to the single-crystalline imine-based covalent organic framework material is 3.0:0.5. The mixed reaction system is evacuated and filled with nitrogen, and the cycle is repeated three times before sealing. The system is heated at 150° C. for 5 days. After the reaction is completed, the product is washed with acetone and tetrahydrofuran solvents in sequence, and vacuum dried to obtain sc-sp 2 c-COF-8.

[0054] Comparative Example 1

[0055] The preparation method of the vinyl-bridged covalent organic framework material in this comparative example includes adding 10.8 mg of tetrakis(4-formylphenyl)methane, 12.5 mg of 1,2,5-trimethylpyrazine-1-iodide, 0.5 mL of mesitylene, 0.5 mL of 1,4-dioxane, and 0.2 mL of trifluoroacetic acid into a quartz glass tube and mixing them evenly, vacuuming and filling the mixed reaction system with nitrogen, performing three cycles, sealing, heating at 150° C. for 3 days, and washing the product with acetone and tetrahydrofuran solvents in sequence after the reaction, and vacuum drying to obtain the vinyl-bridged covalent organic framework material.

[0056] like Figure 1 As shown, the present invention involves a substitution reaction between a single-crystalline imine-based covalent organic framework material and an active monomer in the presence of a catalyst. This monomer replacement allows the conversion of the imine single crystal to a vinyl single crystal, ultimately yielding a single-crystalline vinyl-bridged covalent organic framework material with excellent stability, abundant active sites, high photoelectric activity, and a high degree of conjugation. The single-crystalline vinyl-bridged covalent organic framework materials obtained in Examples 1-8 exhibit excellent electrical conductivity and room-temperature ferromagnetism. The vinyl-bridged covalent organic framework material obtained in Comparative Example 1 exhibits a polycrystalline structure and exhibits poor electrical conductivity and room-temperature ferromagnetism.

[0057] Finally, it should be noted that the specific embodiments described herein are merely illustrative of the spirit of the present invention and are not intended to limit the manner in which the present invention is intended to be implemented. Persons skilled in the art may make various modifications, additions, or substitutions to the described embodiments, and it is not necessary or possible to provide a comprehensive list of all possible embodiments. However, any obvious changes or modifications arising from the essential spirit of the present invention remain within the scope of protection of the present invention, and interpreting them as any additional limitations would be contrary to the spirit of the present invention.

Claims

1. A method for preparing a single-crystalline vinyl-bridged covalent organic framework material, characterized in that: The method comprises uniformly mixing a single crystal imine-based covalent organic framework material, an active monomer and a catalyst and then performing a substitution reaction.

2. The preparation method according to claim 1, characterized in that The molar ratio of the active monomer to the smallest segment of the single crystal imine-based covalent organic framework material is 3.0:0.1-1.

0.

3. The preparation method according to claim 1, characterized in that The substitution reaction is one or more of an aldol condensation reaction, a Knoevenagel condensation reaction, and a Claisen-Schmidt reaction.

4. The preparation method according to claim 1 or 3, characterized in that When the substitution reaction is an aldol condensation reaction, the active monomer is one or both of an oxazine methyl monomer and an azole methyl monomer.

5. The preparation method according to claim 1 or 3, characterized in that When the substitution reaction is a Knoevenagel condensation reaction, the active monomer is a cyano-substituted methylene monomer.

6. The preparation method according to claim 1 or 3, characterized in that When the substitution reaction is a Claisen-Schmidt reaction, the active monomer is an acetylphenyl monomer.

7. The preparation method according to claim 1, characterized in that The catalyst is one or more of benzoic acid, benzoic anhydride, p-toluenesulfonic acid, trifluoroacetic acid, acetic acid, p-toluic anhydride, p-fluorobenzoic acid, phthalic acid, terephthalic acid, trimesic acid, pyromellitic acid, p-toluenesulfonic acid, m-toluic acid, cesium carbonate, sodium hydroxide, potassium hydroxide, and 1,8-diazabicycloundec-7-ene.

8. The preparation method according to claim 1, characterized in that In the preparation method, the components are mixed, vacuumed and filled with nitrogen, and the operation is repeated 3 to 10 times.

9. The preparation method according to claim 1, characterized in that The temperature of the substitution reaction is 80-200° C., and the time is 3-15 days.

10. A single crystal vinyl bridged covalent organic framework material, characterized in that: It is prepared by the preparation method of the single crystal vinyl bridged covalent organic framework material described in claim 1.

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