阅读说明：本技术 一种碳碳双键桥连共价有机框架材料及其制备方法 (Carbon-carbon double bond bridged covalent organic framework material and preparation method thereof ) 是由 张帆 孟凡成 毕帅 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种碳碳双键桥连共价有机框架材料及其制备方法,涉及共价有机框架材料领域。本发明以N-烷基-2,4,6-三甲基吡啶季铵盐为核心单体通过加热反应与2,4,6-三(4-醛基苯基)-1,3,5-三嗪合成碳碳双键桥连共价有机框架材料。以此得到的共价有机框架材料具有高结晶性、高比表面积、规整的开放孔道结构、丰富的光电活性、良好的热稳定性以及二维层状形貌。(The invention discloses a carbon-carbon double bond bridged covalent organic framework material and a preparation method thereof, and relates to the field of covalent organic framework materials. The invention takes N-alkyl-2, 4, 6-trimethyl pyridine quaternary ammonium salt as a core monomer to synthesize a carbon-carbon double bond bridging covalent organic framework material with 2,4, 6-tri (4-aldehyde phenyl) -1,3, 5-triazine through heating reaction. The obtained covalent organic framework material has high crystallinity, high specific surface area, regular open pore channel structure, abundant photoelectric activity, good thermal stability and two-dimensional lamellar morphology.)

1. A preparation method of a carbon-carbon double bond bridged covalent organic framework material is characterized by comprising the following steps:

step 1: in a glove box in argon atmosphere, adding reaction monomers of N-alkyl-2, 4, 6-trimethyl pyridine quaternary ammonium salt, 2,4, 6-tri (4-aldehyde phenyl) -1,3, 5-triazine, solvent anhydrous N, N-Dimethylformamide (DMF), o-dichlorobenzene (o-DCB) and a tetrahydrofuran solution of catalyst dimethylamine into a thick-wall pressure-resistant bottle with the volume of 15 mL;

step 2: sealing the thick-wall pressure-resistant bottle by using a polytetrafluoroethylene spiral plug, transferring the thick-wall pressure-resistant bottle into a constant-temperature oil bath pan, and carrying out heating reaction;

and step 3: and after the heating reaction is finished, naturally cooling the thick-wall pressure-resistant bottle to room temperature, collecting the precipitate by using a vacuum filtration method, washing the precipitate by using acetone, dichloromethane, tetrahydrofuran and methanol respectively, and then performing vacuum drying to obtain the carbon-carbon double bond bridging covalent organic framework material.

2. The method for preparing carbon-carbon double bond bridged covalent organic framework material according to claim 1, wherein the reactive monomer N-alkyl-2, 4, 6-trimethylpyridine quaternary ammonium salt in step 1 is N-methyl-2, 4, 6-trimethylpyridine iodonium salt, N-methyl-2, 4, 6-trimethylpyridine chloride salt, N-methyl-2, 4, 6-trimethylpyridine tetrafluoroborate, N-methyl-2, 4, 6-trimethylpyridine hexafluorophosphate salt, N-ethyl-2, 4, 6-trimethylpyridine bromide salt, N-ethyl-2, 4, 6-trimethylpyridine iodonium salt, N-N-propyl-2, one of 4, 6-trimethyl pyridine bromide salt and N-N-propyl-2, 4, 6-pyridine chloride salt.

3. The method of claim 2, wherein the concentration of the solution of dimethylamine in tetrahydrofuran is 2 mol/L.

4. The method of claim 3, wherein the N-methyl-2, 4, 6-trimethylpyridine iodonium salt, 2,4, 6-tris (4-formylphenyl) -1,3, 5-triazine, anhydrous N, N-dimethylformamide, o-dichlorobenzene, and dimethylamine in tetrahydrofuran are used in amounts of 53mg, 79mg, 7mL, 3mL, and 600 μ L, respectively.

5. The method of claim 3, wherein the N-methyl-2, 4, 6-trimethylpyridine bromide salt, the 2,4, 6-tris (4-formylphenyl) -1,3, 5-triazine, the anhydrous N, N-dimethylformamide and o-dichlorobenzene, and the tetrahydrofuran solution of dimethylamine is used in an amount of 46mg, 79mg, 7mL, 3mL and 600 μ L, respectively.

6. The method of claim 1, wherein the heating in step 2 is carried out at a temperature of 180 ℃ for a period of 72 hours.

7. The method of claim 1, wherein the vacuum drying of step 3 is carried out at a temperature of 60 ℃ for a period of 12 hours.

8. The carbon-carbon double bond bridged covalent organic framework material synthesized by the method for preparing the carbon-carbon double bond bridged covalent organic framework material according to any one of claims 1 to 7.

9. The carbon-carbon double bond bridged covalent organic framework material of claim 8, wherein said carbon-carbon double bond bridged covalent organic framework material has a two-dimensional layered structure.

10. The carbon-carbon double bond bridged covalent organic framework material of claim 8, having a specific surface area of 805m²g^-1-873m²g^-1The pore diameter is 0.8-1.0nm, the visible light absorption is 67-503nm, and the calcination is carried out at 800 ℃ in a nitrogen atmosphere, wherein the residual mass is 41%.

Technical Field

The invention relates to the field of covalent organic framework materials, in particular to a carbon-carbon double bond bridged covalent organic framework material and a preparation method thereof.

Background

Covalent Organic Frameworks (COFs) are porous materials which are formed by connecting light elements (C, H, O, N, B and the like) in two-dimensional or three-dimensional space through covalent bonds and have long-range ordered structures and regular pore channel structures through reversible polymerization under thermodynamic control. The Yaghi task group reports the first two-dimensional COF based on borate ester bond linkage in 2005 (Science,2005,310, 1166) which benefits from rich designability of organic monomers, orderliness and regularity of crystal materials and diversity of covalent bond forms, so that the materials have incomparable advantages of other traditional porous materials such as molecular sieves, porous polymers and metal organic framework Materials (MOFs), such as low density, high specific surface area, easy modification and functionalization and the like, and have been widely researched in the fields of gas storage and separation, heterogeneous catalysis, energy storage materials, photoelectricity, sensing, drug delivery and the like, and show great development prospects. The dynamic covalent bonds which can be used for COFs synthesis at present mainly comprise borate bonds, imine bonds, acylhydrazone bonds, imide bonds and the like, and the chemical bonds have good reversibility, but are weak in the aspects of stability, electron delocalization transmission and the like, so that the functionality of the chemical bonds is influenced, and particularly the deep development and the application expansion of the semiconductor activity are influenced.

In 2016, Zhang topic group reported that polymerization by Knoevenagel condensation (Knoevenagel condensation) to prepare a cyano-substituted carbon-carbon double bond bridged holosp²Carbon conjugated COF (poly. chem.,2016,7, 4176-4181). The novel COF material with carbon-carbon double bond connection shows high stability different from the prior materials and has all sp²-carbon skeleton and effective pi-electron delocalization. Recently, the subject group further develops a plurality of series of covalent organic framework materials without carbon-carbon double bond bridging based on the Knoevenagel condensation reaction, and can precisely cut and regulate the geometric, electronic and topological structures of the COFs through reasonable monomer design. Meanwhile, the related group of topics in the field has made remarkable progress in the preparation and performance development of such materials, for example, Yaghi topic group reports a vinyl bridged COFs capable of supporting a boron lewis acid to catalyze the Diels-Alder reaction (j.am.chem.soc.,2019,141, 6848-; thomas et al found vinyl bond photocyclization between adjacent layers of vinyl bridged COFs (Angew. chem. int. Ed.2019,58, 14865-14870); the COFs prepared by Perepichka et al have high fluorescence quantum yield (up to 50%), and the photophysical properties of such COFs are effectively adjusted by changing monomers (Angew. chem. int. Ed.2019,58, 13753-13757). However, the monomers currently available for the synthesis of unsubstituted carbon-carbon double bond linked two-dimensional COFs are still quite limited.

Therefore, those skilled in the art are working on finding a new functional monomer to synthesize carbon-carbon double bond COFs.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the technical problem to be solved by the present invention is to find a new functional monomer and method for synthesizing carbon-carbon double bond COFs materials.

In order to achieve the purpose, the invention provides a preparation method of a carbon-carbon double bond bridged covalent organic framework material, which is characterized by comprising the following steps:

step 1: in a glove box in argon atmosphere, adding reaction monomers of N-alkyl-2, 4, 6-trimethyl pyridine quaternary ammonium salt, 2,4, 6-tri (4-aldehyde phenyl) -1,3, 5-triazine, solvent anhydrous N, N-Dimethylformamide (DMF), o-dichlorobenzene (o-DCB) and a tetrahydrofuran solution of catalyst dimethylamine into a thick-wall pressure-resistant bottle with the volume of 15 mL;

step 2: sealing the thick-wall pressure-resistant bottle by using a polytetrafluoroethylene spiral plug, transferring the thick-wall pressure-resistant bottle into a constant-temperature oil bath pan, and carrying out heating reaction;

and step 3: and after the heating reaction is finished, naturally cooling the thick-wall pressure-resistant bottle to room temperature, collecting the precipitate by using a vacuum filtration method, washing the precipitate by using acetone, dichloromethane, tetrahydrofuran and methanol respectively, and then performing vacuum drying to obtain the carbon-carbon double bond bridging covalent organic framework material.

Further, the reaction monomers N-alkyl-2, 4, 6-trimethyl pyridine quaternary ammonium salt in the step 1 are N-methyl-2, 4, 6-trimethyl pyridine iodine salt, N-methyl-2, 4, 6-trimethyl pyridine chlorine salt, N-methyl-2, 4, 6-trimethyl pyridine tetrafluoroborate, N-methyl-2, 4, 6-trimethyl pyridine hexafluorophosphate, N-ethyl-2, 4, 6-trimethyl pyridine bromide salt, N-ethyl-2, 4, 6-trimethyl pyridine iodide salt, N-N-propyl-2, 4, 6-trimethyl pyridine bromide salt and N-N-propyl-2, one of 4, 6-pyridinium chloride salts.

Further, the concentration of the tetrahydrofuran solution of dimethylamine is 2 mol/L.

Further, the amounts of the N-methyl-2, 4, 6-trimethylpyridine iodonium salt, 2,4, 6-tris (4-formylphenyl) -1,3, 5-triazine, anhydrous N, N-dimethylformamide, a solution of o-dichlorobenzene and dimethylamine in tetrahydrofuran were 53mg, 79mg, 7mL, 3mL and 600. mu.L, respectively.

Further, the amounts of the N-methyl-2, 4, 6-trimethylpyridine bromide salt, the 2,4, 6-tris (4-formylphenyl) -1,3, 5-triazine, the anhydrous N, N-dimethylformamide and o-dichlorobenzene, and the tetrahydrofuran solution of dimethylamine were 46mg, 79mg, 7mL, 3mL and 600 μ L, respectively.

Further, the reaction temperature of the heating reaction in the step 2 is 180 ℃, and the reaction time is 72 hours.

Further, the drying temperature of the vacuum drying in the step 3 is 60 ℃, and the drying time is 12 hours.

The carbon-carbon double bond bridging covalent organic framework material is synthesized by the method.

Further, the carbon-carbon double bond bridged covalent organic framework material has a two-dimensional layered structure.

Further, the specific surface area of the carbon-carbon double bond bridged covalent organic framework material is 805m²g^-1To 873m²g^-1The pore diameter is 0.8-1.0nm, the visible light absorption is 67-503nm, and the calcination is carried out at 800 ℃ in a nitrogen atmosphere, wherein the residual mass is 41%.

The invention has the following technical effects:

1) the method uses N-alkyl-2, 4, 6-trimethyl pyridine quaternary ammonium salt as a core monomer for the first time, and synthesizes carbon-carbon double bond bridged two-dimensional cationic COFs under the solvothermal condition.

2) The COFs material obtained by the invention has high crystallinity, high specific surface area, periodically arranged pore channel structure, good thermal stability, abundant photoelectric activity and two-dimensional layered morphology.

3) The COFs prepared by the method has abundant pyridine quaternary ammonium salt units and two-dimensional layered morphology, so that favorable conditions are provided for the application of the material in the field of new energy.

The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.

Drawings

FIG. 1 is a schematic diagram of the synthesis and structure of a carbon-carbon double bond bridged covalent organic framework material according to a preferred embodiment of the present invention;

FIG. 2 is an X-ray diffraction pattern and simulated X-ray diffraction pattern of a carbon-carbon double bond bridged covalent organic framework material according to a preferred embodiment of the present invention;

FIG. 3 is a graph of the nitrogen adsorption-desorption isotherm spectrum and pore size distribution of a carbon-carbon double bond bridged covalent organic framework material according to a preferred embodiment of the invention;

FIG. 4 is a scanning electron micrograph of a carbon-carbon double bond bridged covalent organic framework material according to a preferred embodiment of the present invention;

FIG. 5 is a TEM image of a carbon-carbon double bond bridged covalent organic framework material according to a preferred embodiment of the present invention;

FIG. 6 is a graph of the UV-VIS diffuse reflectance spectrum of a carbon-carbon double bond bridged covalent organic framework material in accordance with a preferred embodiment of the present invention;

FIG. 7 is a thermogravimetric analysis of a carbon-carbon double bond bridged covalent organic framework material in a nitrogen atmosphere according to a preferred embodiment of the present invention.

Detailed Description

The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.

Example 1

As shown in FIG. 1, in a glove box under an argon atmosphere, 53mg of N-methyl-2, 4, 6-trimethylpyridine iodonium salt, 79mg of 2,4, 6-tris (4-formylphenyl) -1,3, 5-triazine, 7mL of anhydrous N, N-dimethylformamide, 3mL of o-dichlorobenzene and 600. mu.L of dimethylamine in tetrahydrofuran (2mol/L) were put into a 15mL thick-walled pressure-resistant bottle. The thick-wall pressure-resistant bottle is sealed by a polytetrafluoroethylene screw plug, transferred into a constant-temperature oil bath pot, and heated to 180 ℃ for reaction for 72 hours. And after the reaction is finished, naturally cooling the reaction bottle to room temperature, collecting filter residues by a vacuum filtration method, respectively leaching the filter residues by acetone, dichloromethane, tetrahydrofuran and methanol, collecting solid products, and drying the solid products in vacuum at 60 ℃ for 12 hours to obtain light yellow solid which is named as COF-Me-I.

Example 2

As shown in FIG. 1, in a glove box under an argon atmosphere, 46mg of N-ethyl-2, 4, 6-trimethylpyridine bromide, 79mg of 2,4, 6-tris (4-formylphenyl) -1,3, 5-triazine, 7Ml of anhydrous N, N-dimethylformamide and 3Md L of o-dichlorobenzene and 600. mu.L of dimethylamine in tetrahydrofuran (2mol/L) were put into a 15Ml thick-walled pressure-resistant bottle. The thick-wall pressure-resistant bottle is sealed by a polytetrafluoroethylene screw plug, transferred into a constant-temperature oil bath pot, and heated to 180 ℃ for reaction for 72 hours. And after the reaction is finished, naturally cooling the reaction bottle to room temperature, collecting filter residues by a vacuum filtration method, respectively leaching the filter residues by acetone, dichloromethane, tetrahydrofuran and methanol, collecting solid products, and drying the solid products in vacuum at 60 ℃ for 12 hours to obtain light yellow solid which is named as COF-Et-Br.

As shown in fig. 2, the resulting powder X-ray diffraction pattern of two carbon-carbon double bond bridged two-dimensional cationic covalent organic frameworks is consistent with the results of theoretical simulations. The results show that the prepared sample belongs to a hexagonal system and has good crystallinity.

As shown in fig. 3, a scanning electron micrograph of the two carbon-carbon double bond bridged two-dimensional cationic covalent organic framework is obtained. The result shows that the prepared two-dimensional carbon-carbon double bond bridged two-dimensional cationic covalent organic framework has a two-dimensional layered morphology.

As shown in fig. 4, a transmission electron micrograph of the two carbon-carbon double bond bridged two-dimensional cationic covalent organic framework is obtained. The result shows that the prepared two-dimensional carbon-carbon double bond bridged cationic covalent organic frameworks have the appearance of layer-by-layer stacking and provide a foundation for further stripping.

As shown in fig. 5, the obtained nitrogen adsorption isotherm and pore size distribution graph of two carbon-carbon double bond bridged two-dimensional cationic covalent organic frameworks. The result shows that the prepared two-dimensional cationic covalent organic framework bridged by two carbon-carbon double bonds has a porous structure and the BET specific surface area is 805m²g^-1And 873m²g^-1Pore size distribution centered at 0.93nm and 0.86nm。

As shown in fig. 6, the obtained ultraviolet-visible diffuse reflection spectrum of the two-dimensional cationic covalent organic frameworks bridged by the carbon-carbon double bond is shown. The result shows that the absorption band edge wavelengths of the two prepared carbon-carbon double bond bridged two-dimensional cationic covalent organic frameworks are 503nm and 467nm respectively, and the two prepared carbon-carbon double bond bridged two-dimensional cationic covalent organic frameworks cover part of visible light bands.

FIG. 7 is a thermogravimetric analysis of a carbon-carbon double bond bridged covalent organic framework material in a nitrogen atmosphere according to a preferred embodiment of the present invention.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.