Metal-based covalent organic framework photocatalyst as well as preparation method and application thereof
By preparing metal-based covalent organic frame photocatalysts, using the two-dimensional HCB topological network structure formed by tri-core metal clusters and phenothiazine monomers, the problem of direct functionalization of amide bonds in the prior art is solved, and efficient and environmentally friendly photocatalytic synthesis of saturated alumina heterocyclic compounds has good stability and reusability.
Patent Information
- Application Number
- CN202510592797.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-09
- Publication Date
- 2025-08-08
AI Technical Summary
In the prior art, the direct functionalization method of amide bonds is limited by the use of dangerous and expensive materials or harsh reaction conditions, and it is difficult to achieve simple, selective, and environmentally friendly photocatalytic synthesis of saturated azoheterocyclic compounds.
Using a metal-based covalent organic frame photocatalyst, a tri-core metal cluster monomer and a phenothiazine monomer are connected to each other in a two-dimensional plane to form a two-dimensional HCB topological network structure. It is prepared by [3+3]imine condensation reaction and is used as a heterophase photocatalyst for photocatalyzing the methylaminoylation of saturated azoheterocyclic compounds.
The catalyst has high crystallinity and chemical stability, and can maintain good catalytic performance after multiple reuses, providing a green, economical and efficient synthesis pathway, suitable for the synthesis of saturated azoheterocyclic compounds.
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Abstract
Description
Technical Field
[0001] The present invention relates to the field of photocatalysis technology, and in particular to a metal-based covalent organic framework photocatalyst and a preparation method and application thereof. Background Art
[0002] Amide bonds are widely present in various functional proteins, marketed drugs, biomaterials, synthetic intermediates and additives. Functionalized saturated nitrogen heterocycles often appear in various functional molecules, such as alkaloids, clinical drugs, chiral additives, etc. 3 Direct functionalization of )-H bonds provides a promising approach to obtain complex and valuable nitrogen heterocycles. Developing new methods based on visible light photocatalytic redox reactions to directly attach valuable amide functional groups to saturated nitrogen heterocycles with medicinal potential is of great significance. Covalent organic frameworks (COFs) are a unique class of polymer materials that are obtained by connecting building blocks through covalent atomic bonds. COFs have periodic structures, high specific surface areas, good porosity and designable structures, and are becoming a new research frontier in the fields of energy storage, separation, sensing and catalysis.
[0003] Over the past decade, visible-light-mediated photoredox catalysis has developed into a powerful and mild tool for creating new chemical bonds under mild conditions through unique single-electron transfer or energy transfer pathways. Saturated nitrogen heterocycles containing amide bonds often exhibit good biological activities. Therefore, since the birth of organic chemistry, the formation of amide bonds has attracted great attention in the organic synthesis community, and various strategies and methods have been developed to construct this valuable bond. Currently available methods are limited by the use of hazardous and expensive materials or require harsh reaction conditions. Therefore, it is of great significance to provide a simple, selective, and environmentally friendly method for the photoinduced synthesis of such compounds based on COFs. Summary of the Invention
[0004] Based on the above content, the present invention provides a metal-based covalent organic framework photocatalyst and its preparation method and application.
[0005] To achieve the above object, the present invention provides the following solutions:
[0006] One of the technical solutions of the present invention is a metal-based covalent organic framework photocatalyst, which is composed of a trinuclear metal cluster monomer having a structure shown in Formula I and a phenothiazine monomer having a structure shown in Formula II connected to each other in a two-dimensional plane to form a two-dimensional HCB topological network structure;
[0007]
[0008]
[0009] The dotted lines in Formula I and Formula II represent the connection sites;
[0010] In formula I, M is Cu, Ag or Au.
[0011] The second technical solution of the present invention is a method for preparing the above-mentioned metal-based covalent organic framework photocatalyst, comprising the following steps:
[0012] The compound having the structure represented by Formula IV, the compound having the structure represented by Formula V, and the catalyst are uniformly dispersed in a reaction solvent and subjected to a freezing-vacuuming-thawing step, and the freezing-vacuuming-thawing step is repeated and then allowed to react to obtain the metal-based covalent organic framework photocatalyst;
[0013]
[0014] Wherein, R1 and R2 are independently aldehyde or amino. Preferably, R1 is aldehyde and R2 is amino.
[0015] The third technical solution of the present invention is the use of the above-mentioned metal-based covalent organic framework photocatalyst in the photocatalytic carbamoylation of saturated nitrogen heterocyclic compounds.
[0016] The present invention discloses the following technical effects:
[0017] This invention utilizes trinuclear metal clusters and phenothiazine monomers to produce a two-dimensional HCB-type metal-based covalent organic framework photocatalyst via [3+3] imine condensation. This metal-based covalent organic framework photocatalyst exhibits high crystallinity, chemical stability, and a unique pore structure. It can be used as a heterogeneous photocatalyst for the photocatalytic C-H carbamoylation of saturated nitrogen heterocyclic compounds. The catalyst maintains excellent catalytic performance after repeated reuse, with no significant decrease in activity. This provides a green, economical, and efficient synthetic route for the synthesis of saturated nitrogen heterocyclic compounds, with significant application value. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0019] Figure 1 Schematic diagram of the topological structure of the metal-based covalent organic framework photocatalyst of the present invention;
[0020] Figure 2The powder X-ray diffraction (PXRD) test spectrum and simulated spectrum of the metal-based covalent organic framework photocatalyst prepared in Example 1 of the present invention;
[0021] Figure 3 This is a Fourier transform infrared (FT-IR) spectrum of the metal-based covalent organic framework photocatalyst prepared in Example 1 of the present invention;
[0022] Figure 4 The powder X-ray diffraction patterns of the metal-based covalent organic framework photocatalyst prepared in Example 1 of the present invention before and after reuse;
[0023] Figure 5 The results of repeated experiments on the catalytic reaction of the metal-based covalent organic framework photocatalyst prepared in Example 1 of the present invention are as follows;
[0024] Figure 6 This is the thermogravimetric (TG) graph of the metal-based covalent organic framework photocatalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0026] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.
[0027] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.
[0028] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.
[0029] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.
[0030] The first aspect of the present invention provides a metal-based covalent organic framework photocatalyst, which is composed of a trinuclear metal cluster monomer having a structure shown in Formula I and a phenothiazine monomer having a structure shown in Formula II connected to each other in a two-dimensional plane to form a two-dimensional HCB topological network structure;
[0031]
[0032] The dotted lines in Formula I and Formula II represent the connection sites;
[0033] In formula I, M is Cu, Ag or Au.
[0034] In a preferred embodiment of the present invention, each trinuclear metal cluster monomer is connected to three phenothiazine monomers, and each phenothiazine monomer is connected to three trinuclear metal cluster monomers.
[0035] In a preferred embodiment of the present invention, the connecting group between the trinuclear metal cluster monomer and the phenothiazine monomer is one of -C=N-, -C=NN=C-, -C=N-NH-, -C=C-, and -C=C(CN)-.
[0036] In a preferred embodiment of the present invention, the molar ratio of the trinuclear metal cluster monomer to the phenothiazine monomer is (0.5-1.5): (1.5-2.5).
[0037] In a preferred embodiment of the present invention, the skeleton unit of the metal-based covalent organic framework photocatalyst is as shown in Formula III;
[0038]
[0039] The BET specific surface area of the metal-based covalent organic framework photocatalyst of this embodiment is 50-5000 m 2 / g, pore size is 0.5~5nm.
[0040] A second aspect of the present invention provides a method for preparing the above-mentioned metal-based covalent organic framework photocatalyst, comprising the following steps:
[0041] The compound having the structure represented by Formula IV, the compound having the structure represented by Formula V, and the catalyst are uniformly dispersed in a reaction solvent and subjected to a freezing-vacuuming-thawing step, and the freezing-vacuuming-thawing step is repeated and then allowed to react to obtain the metal-based covalent organic framework photocatalyst;
[0042]
[0043] Wherein, R1 and R2 are independently aldehyde or amino. Preferably, R1 is aldehyde and R2 is amino.
[0044] In a preferred embodiment of the present invention, the catalyst is 3 to 12 mol / L glacial acetic acid;
[0045] The reaction solvent is a mixed solvent of mesitylene and dioxane in a volume ratio of (1-9):1;
[0046] The temperature of the static reaction is 70 to 150° C. and the time is 72 to 120 hours;
[0047] The molar ratio of the compound having the structure represented by Formula IV to the compound having the structure represented by Formula V is 1:1;
[0048] The concentration of the compound having the structure represented by Formula V in the reaction system is 0.01-0.02 mol / L;
[0049] The volume concentration of the catalyst in the reaction system is 10% to 20%.
[0050] After the standing reaction, the method further comprises the steps of washing the solid, performing Soxhlet extraction and then drying.
[0051] The washing is specifically washing with N,N-dimethylacetamide, 1,4-dioxane, tetrahydrofuran, and dichloromethane in sequence, and the Soxhlet extraction is specifically Soxhlet extraction with tetrahydrofuran and chloroform respectively for 24 to 48 hours.
[0052] The drying is specifically performed in a vacuum drying oven (vacuum degree is 10 mTorr) at 100° C. for 24 hours.
[0053] The third aspect of the present invention provides the use of the above-mentioned metal-based covalent organic framework photocatalyst in the photocatalytic carbamoylation of saturated nitrogen heterocyclic compounds.
[0054] In a preferred embodiment of the present invention, the metal-based covalent organic framework photocatalyst, tertiary aromatic amine, isocyanide, pentafluoronitrobenzene and p-toluenesulfonic acid are added to a solvent for reaction to obtain a carbamoylation product of a saturated nitrogen heterocyclic compound.
[0055] In a preferred embodiment of the present invention, the ratio of the metal-based covalent organic framework photocatalyst, tertiary aromatic amine, isocyanide, pentafluoronitrobenzene, p-toluenesulfonic acid and solvent is 5 mg: 0.1 mmol: 0.15 mmol: 0.05 mmol: 0.01 mmol: 2 mL;
[0056] The reaction is specifically as follows: reacting at room temperature for 12 hours under oxygen atmosphere and blue LED conditions.
[0057] Unless otherwise specified, the technical solutions described in the present invention are all conventional solutions in the field, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.
[0058] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0059] Example 1
[0060] Trinuclear copper cluster aldehyde monomer (Cu3-CHO) (14.21 mg, 0.03 mmol) and phenothiazine amine monomer (Phz-NH2) (16.44 mg, 0.03 mmol) were added to a mixed reaction solvent of mesitylene (1.0 mL) and dioxane (1.0 mL) and uniformly dispersed by ultrasonication in an ampoule to obtain a brown turbid solution;
[0061] The catalyst, glacial acetic acid (0.2 mL, 6 M), was added to an ampoule and quickly frozen in a liquid nitrogen bath at 77 K. After three cycles of freeze-vacuum-thaw, the mixture was vacuum-degassed and then sealed with a flame gun.
[0062] The ampoule containing the sample was placed in a 120°C oven for 3 days. After the reaction was completed, the ampoule was returned to room temperature and filtered to collect the dark green solid.
[0063] The collected dark green solid was washed with N,N-dimethylacetamide, 1,4-dioxane, tetrahydrofuran and dichloromethane in sequence, and then Soxhlet extracted with tetrahydrofuran and chloroform for 24 h and 48 h, respectively. Finally, the sample was dried in a vacuum drying oven at 100 ° C for 24 h to obtain a metal-based covalent organic framework photocatalyst, designated as Cu3-Phz-COF, with a yield of 80.3% and a specific surface area of 1855 m 2 g - 1, pore size 2.5nm. The topological structure diagram of the metal-based covalent organic framework photocatalyst is shown in Figure 1 shown.
[0064] Example 1 The reaction formula for preparing a metal-based covalent organic framework photocatalyst is shown below:
[0065]
[0066] The metal-based covalent organic framework photocatalyst prepared in Example 1 was characterized, and the results are as follows:
[0067] like Figure 2As shown in the figure (in the figure, Experimental represents the experimental PXRD, Refined represents the refined PXRD, Calculated represents the simulated PXRD, Difference represents the difference between the reagent and the simulated PXRD, and Bragg position represents the angular position of the diffraction peak), the powder X-ray diffraction test results show that diffraction peaks appear at 2theta: 3.58, 6.20, 7.93, 8.47, 9.44, 11.67, 12.37, and 22.58. The structure was simulated using Materials Studio software, and the crystal structure of the covalent organic framework photocatalyst was analyzed. The simulated PXRD pattern generated by the corresponding two-dimensional hcb topological structure matched well with the experimental PXRD, proving the correctness of the structure.
[0068] like Figure 3 As shown, the Fourier transform infrared (FT-IR) spectroscopy test results show that the comparison of the infrared spectra of the monomers required for the synthesis of Cu3-Phz-COF and the products proves that the metal-based covalent organic framework photocatalyst was successfully synthesized.
[0069] The application of the metal-based covalent organic framework photocatalyst prepared in Example 1 in the photocatalytic carbamoylation of saturated nitrogen heterocyclic compounds was tested as follows:
[0070] In a photocatalytic reaction tube, metal-based covalent organic framework photocatalyst (5 mg), tertiary aromatic amine (0.1 mmol), isocyanide (0.15 mmol), pentafluoronitrobenzene (PFNB, 0.05 mmol), p-toluenesulfonic acid (TsOH, 0.01 mmol) and chloroform (2 mL) solvent were added thereto;
[0071] The reaction was carried out at room temperature for 12 h under an oxygen atmosphere and a blue LED (10 W);
[0072] After the reaction was completed, the supernatant was centrifuged and diluted with ethanol, and analyzed by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy ( 1 The product was analyzed by HNMR. The metal-based covalent organic framework photocatalyst was washed three times with ethanol after the reaction, dried naturally, and then recycled for the next use.
[0073] Taking 1-phenylpyrrolidine (1a) and tert-butyl isocyanate (2a) as an example, the yield of product 3a was 87%.
[0074] The reaction formula is:
[0075]
[0076] 1H NMR (400MHz, CDCl3): δ7.26(t,J=8.0Hz,2H),6.82(d,J=8.0Hz,1H),6.63(d,J=8.0Hz,2H),6.36(s,1H),3. 86-3.83(m,1H),3.65-3.60(m,1H),3.23-3.19(m,1H),2.23-2.19(m,1H),2.05-1.90(m,2H),1.29(s,9H).
[0077] Table 1 shows the yields of carbamoylation of different saturated nitrogen heterocyclic compounds under the catalysis of metal-based covalent organic framework photocatalysts. It can be seen that this catalyst can be widely used in the synthesis of this type of compounds;
[0078] The metal-based covalent organic framework photocatalyst catalyzes the carbamoylation of saturated nitrogen heterocyclic compounds as follows:
[0079]
[0080] Wherein, Ar is a different aromatic group, and R is a different substituent group. A series of products were prepared using this method, as shown below:
[0081]
[0082] like Figure 4 As shown (Figure, After 3 rd ("test" indicates after three cycles of use, and "Before test" indicates before use). After three cycles of the metal-based covalent organic framework photocatalyst in the preparation of product 3a by carbamoylation of saturated nitrogen heterocyclic compounds, there was no obvious change in PXRD, indicating that the catalyst has good stability and can be recycled.
[0083] like Figure 5 As shown, the metal-based covalent organic framework photocatalyst has good reusability in the application of carbamoylation of saturated nitrogen heterocyclic compounds to prepare product 3a. After three cycles of use, the yield of the target product is >80%.
[0084] Figure 6 This is the thermogravimetric (TG) graph of the metal-based covalent organic framework photocatalyst prepared in Example 1 of the present invention. Figure 6 It can be seen that the metal-based covalent organic framework photocatalyst has good thermal stability, which can reach 390°C.
[0085] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.
Claims
1. A metal-based covalent organic framework photocatalyst, characterized in that: A two-dimensional hcb topological network structure is formed by interconnecting a trinuclear metal cluster monomer having a structure shown in formula I and a phenothiazine monomer having a structure shown in formula II in a two-dimensional plane; The dotted lines in Formula I and Formula II represent the connection sites; In formula I, M is Cu, Ag or Au.
2. The metal-based covalent organic framework photocatalyst according to claim 1, characterized in that Each trinuclear metal cluster monomer is connected to three phenothiazine monomers, and each phenothiazine monomer is connected to three trinuclear metal cluster monomers.
3. The metal-based covalent organic framework photocatalyst according to claim 1, characterized in that The connecting group between the trinuclear metal cluster monomer and the phenothiazine monomer is one of -C=N-, -C=NN=C-, -C=N-NH-, -C=C-, and -C=C(CN)-.
4. The metal-based covalent organic framework photocatalyst according to claim 1, characterized in that The molar ratio of the trinuclear metal cluster monomer to the phenothiazine monomer is (0.5-1.5): (1.5-2.5).
5. The metal-based covalent organic framework photocatalyst according to claim 1, characterized in that The skeleton unit of the metal-based covalent organic framework photocatalyst is shown in Formula III; 6. A method for preparing the metal-based covalent organic framework photocatalyst according to claim 1, characterized in that: The following steps are involved: The compound having the structure represented by Formula IV, the compound having the structure represented by Formula V, and the catalyst are uniformly dispersed in a reaction solvent and subjected to a freezing-vacuuming-thawing step, and the freezing-vacuuming-thawing step is repeated and then allowed to react to obtain the metal-based covalent organic framework photocatalyst; Wherein, R1 and R2 are independently aldehyde or amino.
7. The preparation method according to claim 6, characterized in that The catalyst is 3-12 mol / L glacial acetic acid; The reaction solvent is a mixed solvent of mesitylene and dioxane in a volume ratio of (1-9):1; The temperature of the static reaction is 70 to 150° C. and the time is 72 to 120 hours; The molar ratio of the compound having the structure represented by Formula IV to the compound having the structure represented by Formula V is 1:1; The concentration of the compound having the structure represented by Formula V in the reaction system is 0.01-0.02 mol / L; The volume concentration of the catalyst in the reaction system is 10% to 20%.
8. Use of the metal-based covalent organic framework photocatalyst according to any one of claims 1 to 5 in the photocatalytic carbamoylation of saturated nitrogen heterocyclic compounds.
9. The use according to claim 8, characterized in that The metal-based covalent organic framework photocatalyst according to any one of claims 1 to 5, tertiary aromatic amine, isocyanide, pentafluoronitrobenzene and p-toluenesulfonic acid are added into a solvent for reaction to obtain a carbamoylation product of a saturated nitrogen heterocyclic compound.
10. The use according to claim 8, characterized in that The ratio of the metal-based covalent organic framework photocatalyst, tertiary aromatic amine, isocyanide, pentafluoronitrobenzene, p-toluenesulfonic acid and solvent is 5 mg: 0.1 mmol: 0.15 mmol: 0.05 mmol: 0.01 mmol: 2 mL; The reaction is specifically as follows: reacting at room temperature for 12 hours under oxygen atmosphere and blue LED conditions.