A nitrogen-rich acylhydrazone-based covalent organic framework material, a preparation method and application thereof

Abstract

The present application relates to a kind of nitrogen-rich acylhydrazone-based covalent organic framework material and its preparation method and application, to 5'-(4-(hydrazine carbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-tri phenyl]-4,4''-dicarboxylic dihydrazine, 1,3,5-tri (2-formylpyridine-5yl) Benzene and 4,4',4''-(1,3,5-triazine-2,4,6-triazyl) triphenyl formaldehyde as building unit, synthesis using Schiff base reaction.The nitrogen-rich acylhydrazone-based covalent organic framework material of the present application has good chemical stability, and can be used as carrier by metal coordination effect Palladium nanoparticles are loaded to obtain composite material, and the composite material shows excellent catalytic activity and substrate universality in catalyzing Heck reaction, has potential application value in the field of biological medicine and green chemistry.

Description

Technical Field

[0001] This invention belongs to the field of covalent organic framework materials technology, and specifically relates to a nitrogen-rich acylhydrazone-based covalent organic framework material, its preparation method, and its application. Background Technology

[0002] The Heck reaction refers to the coupling reaction between unsaturated haloalkanes and alkenes under the action of a strong base and a palladium catalyst. It can efficiently and selectively generate substituted alkenes and has wide applications in chemistry, medicine, and materials science, serving as an important bridge between basic research and practical applications. Although traditional homogeneous palladium catalysts exhibit excellent catalytic performance, they suffer from several significant drawbacks: the catalyst is difficult to separate and recover from the system after the reaction, leading to catalyst waste and increased costs; furthermore, palladium has high toxicity, which places high demands on post-processing and purification of products in the pharmaceutical industry. To address this issue, preparing heterogeneous catalysts by supporting palladium on specific supports has become an effective solution. These catalysts not only enable efficient recovery and separation but also reduce the residual amount of free palladium in the system. Therefore, the development of heterogeneous palladium catalysts with high catalytic activity and stability has become a key research focus.

[0003] Covalent organic frameworks (COFs) are porous crystalline polymers formed by organic monomers linked by covalent bonds, possessing advantages such as large specific surface area, good chemical stability, and tunable structure and function. As a novel class of organic porous functional materials, acylhydrazone-based COFs not only exhibit high specific surface area and good stability but also possess advantages such as functional tunability and abundant heteroatom sites, thus being considered an ideal support for controllably loading palladium nanoparticles. Utilizing the metal coordination between palladium and the abundant nitrogen atoms in acylhydrazone-based COFs, composite materials with both high catalytic activity and high stability can be constructed for efficient catalysis of the Heck reaction. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a nitrogen-rich acylhydrazone-based covalent organic framework material, its preparation method and application, so as to overcome the shortcomings of the heterogeneous catalysts used in the Heck reaction in terms of reaction activity and stability.

[0005] This invention provides a nitrogen-rich acylhydrazone-based covalent organic framework material, the general structural formula of which is:

[0006] , At least one of the following: X is independently selected from hydrogen, alkyl, alkoxy, hydroxy, cyano, nitro, mercapto, and halogen; R is independently selected from hydrogen, alkyl, and alkoxy.

[0007] This invention also provides a method for preparing a nitrogen-rich acylhydrazone-based covalent organic framework material, comprising the following steps:

[0008] The nitrogen-rich acylhydrazone covalent organic framework material is obtained by reacting tribenzoylhydrazide monomer with aromatic aldehyde monomer via Schiff base reaction.

[0009] Preferably, the general structural formula of the mesitylene benzoyl hydrazine monomer is: Wherein, X is independently selected from one of hydrogen, alkyl, alkoxy, hydroxy, cyano, nitro, mercapto, and halogen; R is independently selected from one of hydrogen, alkyl, and alkoxy.

[0010] Preferably, the general structural formula of the aromatic aldehyde monomer is: X, Y, and Z are each independently selected from at least one of carbon and nitrogen atoms.

[0011] Preferably, the tribenzoylhydrazine monomer is 5'-(4-(hydrazylcarbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dihydrazide HMDTD.

[0012] Further, the preparation method of the 5'-(4-(hydrazylcarbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dihydrazide includes:

[0013] Dimethyl 3,3''-dimethoxy-5'-(3-methoxy-4-(methoxycarbonyl)phenyl)-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dimethyl ester, hydrazine hydrate, ethanol, and toluene were mixed and then stirred under reflux to obtain the final product.

[0014] Furthermore, the molar ratio of 3,3''-dimethoxy-5'-(3-methoxy-4-(methoxycarbonyl)phenyl)-[1,1':3',1''-terphenyl]-4,4''-dimethyl dicarboxylate to hydrazine hydrate is 1:6.

[0015] Furthermore, the reaction temperature is 60~100℃. o C, the reaction time is 24~48 h.

[0016] Preferably, the aromatic aldehyde monomer is at least one of 1,3,5-tris(2-formylpyridin-5-yl)benzene BTTPA and 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde TATTA.

[0017] Furthermore, the molar ratio of the tribenzoyl hydrazine monomer to the aromatic aldehyde monomer in the Schiff base reaction system is 1:1.

[0018] Furthermore, the Schiff base reaction system also includes a solvent and an acid catalyst.

[0019] Further, the solvent is 1,2-dichlorobenzene and n-butanol or 1,4-dioxane and 1,3,5-trimethylbenzene; the acid catalyst is an acetic acid solution.

[0020] Furthermore, the volume ratio of the 1,2-dichlorobenzene, n-butanol, and acetic acid solution is 8:2:1; the volume ratio of the 1,3,5-trimethylbenzene, 1,4-dioxane, and acetic acid solution is 5:5:1.

[0021] Preferably, the Schiff base reaction system is held at a temperature of 120-150°C. o C, the reaction time is 3 to 5 days.

[0022] This invention also provides the application of nitrogen-rich acylhydrazone-based covalent organic framework materials in the catalytic Heck reaction.

[0023] Preferably, the composite material is obtained by loading palladium nanoparticles through metal coordination using the nitrogen-rich hydrazone-based covalent organic framework material as a carrier.

[0024] Furthermore, the preparation method of the composite material includes the following steps: continuously stirring palladium acetate, dichloromethane and nitrogen-rich hydrazone-based covalent organic framework material at room temperature in sequence; then collecting the generated solid by centrifugation, washing with excess dichloromethane and vacuum drying to obtain the composite material.

[0025] Furthermore, the mass ratio of the palladium acetate to the nitrogen-rich hydrazone-based covalent organic framework material is 3~15:20.

[0026] Beneficial effects

[0027] (1) The present invention synthesizes nitrogen-rich acylhydrazone covalent organic framework material by Schiff base reaction. It has excellent chemical stability and can withstand a variety of chemical solvents while maintaining the regularity and porosity of the framework.

[0028] (2) The nitrogen-rich acylhydrazone-based covalent organic framework material of the present invention contains abundant nitrogen atoms, which can load uniform and stable palladium nanoparticles through metal coordination, providing theoretical guidance and experimental examples for the design of function-oriented covalent organic framework materials.

[0029] (3) The nitrogen-rich hydrazone-based covalent organic framework material loaded with palladium nanoparticles in this invention exhibits excellent catalytic activity in the Heck reaction and has important application potential in the fields of biomedicine and green chemistry. Attached Figure Description

[0030] Figure 1 The 5'-(4-(hydrazylcarbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dihydrazide synthesized in Example 1 1 H NMR spectrum.

[0031] Figure 2 This is a schematic diagram of the synthetic route for the nitrogen-rich acylhydrazone-based covalent organic framework material of the present invention; the monomers involved include 5'-(4-(hydrazylcarbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dihydrazide (HMDTD), 1,3,5-tris(2-formylpyridin-5-yl)benzene (BTTPA), and 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde (TATTA).

[0032] Figure 3 The Fourier transform infrared spectra of the COF-BH material synthesized in Example 2 and its corresponding monomers HMDTD and BTTPA are shown.

[0033] Figure 4 The Fourier transform infrared spectra of the COF-TH material synthesized in Example 4 and its corresponding monomers HMDTD and TATTA are shown.

[0034] Figure 5 The powder X-ray diffraction patterns are those of the COF-BH material synthesized in Example 2 and the Pd@COF-BH material synthesized in Example 3.

[0035] Figure 6 The images show the powder X-ray diffraction patterns of the COF-TH material synthesized in Example 4 and the Pd@COF-TH material synthesized in Example 5.

[0036] Figure 7 The solid-state NMR carbon spectrum of the COF-BH material synthesized in Example 2.

[0037] Figure 8 The solid-state carbon NMR spectrum of the COF-TH material synthesized in Example 4.

[0038] Figure 9 The nitrogen adsorption-desorption curves and BET specific surface areas of the COF-BH material synthesized in Example 2 and the Pd@COF-BH material synthesized in Example 3 are shown.

[0039] Figure 10The nitrogen adsorption-desorption curves and BET specific surface areas of the COF-TH material synthesized in Example 4 and the Pd@COF-TH material synthesized in Example 5 are shown.

[0040] Figure 11 Transmission electron microscope (TEM) images of the COF-BH material synthesized in Example 2 and the Pd@COF-BH material synthesized in Example 3.

[0041] Figure 12 Transmission electron microscopy (TEM) images of the COF-TH material synthesized in Example 4 and the Pd@COF-TH material synthesized in Example 5.

[0042] Figure 13 The thermogravimetric analysis curves of the COF-BH material synthesized in Example 2 are shown.

[0043] Figure 14 The thermogravimetric analysis curves of the COF-TH material synthesized in Example 4 are shown.

[0044] Figure 15 This is a comparison chart of the conversion rates of the four materials (COF-BH, Pd@COF-BH, COF-TH, and Pd@COF-TH) catalyzing the Heck reaction under the same conditions in Example 6.

[0045] Figure 16 The conversion rate of the Pd@COF-BH material in Example 7 for the Heck reaction of different iodobenzene substrates with styrene is shown.

[0046] Figure 17 This is a schematic diagram of the structure of the nitrogen-rich acylhydrazone-based covalent organic framework material of the present invention. Detailed Implementation

[0047] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0048] Raw material sources: 3,3''-dimethoxy-5'-(3-methoxy-4-(methoxycarbonyl)phenyl)-[1,1':3',1''-terphenyl]-4,4''-dimethyl dicarboxylate (Jilin Zhongke Science & Technology Co., Ltd.), hydrazine hydrate (85wt%, Sinopharm Chemical Reagent Co., Ltd.), 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde (Jilin Zhongke Science & Technology Co., Ltd.), 5,5',5''-(benzene-1,3,5-triyl)tribenzaldehyde (Jilin Zhongke Science & Technology Co., Ltd.).

[0049] Example 1

[0050] Dimethyl 3,3''-dimethoxy-5'-(3-methoxy-4-(methoxycarbonyl)phenyl)-[1,1':3',1''-terphenyl]-4,4''-dicarboxylate (1.0 g, 1.75 mmol), hydrazine hydrate (15.0 mL, 10.5 mmol), ethanol (10.0 mL), and toluene (10.0 mL) were added sequentially to a 100 mL single-necked round-bottom flask. o After heating under reflux for 24 h, the mixture was cooled to room temperature, filtered, and washed with a large amount of ethanol to give a white powder of 5'-(4-(hydrazylcarbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dihydrazide (0.79 g, 1.38 mmol), with a yield of 79%.

[0051] The NMR spectrum of 5'-(4-(hydrazinylcarbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dihydrazide obtained in this embodiment is as follows: Figure 1 As shown.

[0052] Example 2

[0053] 1,3,5-tris(2-formylpyridin-5-yl)benzene (10.0 mg, 0.025 mmol) and 5'-(4-(hydrazylcarbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dihydrazide (14.5 mg, 0.025 mmol), 1,2-dichlorobenzene (0.8 mL), n-butanol (0.2 mL), and acetic acid solution (6 mol / L, 0.1 mL) obtained in Example 1 were sequentially added to an ampoule (2.0 mL) and ultrasonically dispersed for 10 min. The ampoule was then evacuated and backfilled with nitrogen three times. The ampoule was then sealed under vacuum and placed at 150°C. o The reaction was carried out in a constant temperature oven at C for 3 days. After the reaction was completed, the mixture was cooled to room temperature and filtered through a sintered glass funnel. The product was washed successively with tetrahydrofuran and n-hexane and then dried under vacuum for 12 h to obtain a brown powdery COF-BH material (19.6 mg), with a yield of 84.7%.

[0054] The schematic diagram of the synthesis route of the COF-BH material obtained in this embodiment is shown below. Figure 2 As shown, the Fourier transform infrared spectrum is as follows: Figure 3 As shown, the powder X-ray diffraction pattern is as follows: Figure 5 As shown, the solid-state carbon NMR spectrum is as follows: Figure 7 As shown, the nitrogen adsorption-desorption curves are as follows: Figure 9 As shown, the transmission electron microscope image is as follows: Figure 11 As shown, the thermogravimetric analysis curve is as follows: Figure 13 As shown in the figure, the prepared COF-BH material possesses a crystalline framework, regular and ordered pores, and good thermal stability.

[0055] Example 3

[0056] Palladium acetate (15 mg, 0.067 mmol), dichloromethane (10 mL), and COF-BH obtained in Example 2 (20 mg) were added sequentially to a 25 mL round-bottom flask. The mixture was stirred continuously at room temperature for 24 hours. Subsequently, the solid generated was collected by centrifugation, washed with excess dichloromethane, and vacuum dried for 6 h to obtain a reddish-brown powdery Pd@COF-BH composite material.

[0057] The powder X-ray diffraction pattern of the Pd@COF-BH material obtained in this example is as follows: Figure 5 As shown, the nitrogen adsorption-desorption curves are as follows: Figure 9 As shown, the transmission electron microscope image is as follows: Figure 11 As shown in the figure, the results above indicate that, compared with COF-BH material, Pd@COF-BH material retains its crystallinity and has an increased specific surface area.

[0058] Example 4

[0059] 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde (10.0 mg, 0.025 mmol) and 5'-(4-(hydrazylcarbonyl)-3-methoxyphenyl)-3,3''-dimethoxy-[1,1':3',1''-terphenyl]-4,4''-dicarboxylic acid dihydrazide (14.5 mg, 0.025 mmol), 1,3,5-trimethylbenzene (0.5 mL), 1,4-dioxane (0.5 mL), and acetic acid solution (9 mol / L, 0.1 mL) obtained in Example 1 were sequentially added to an ampoule (2.0 mL) and ultrasonically dispersed for 10 min. The ampoule was then evacuated and backfilled with nitrogen three times. The ampoule was then sealed under vacuum and placed at 120°C. o The reaction was carried out in a constant temperature oven at C for 3 days. After the reaction was completed, the mixture was cooled to room temperature and filtered through a sintered glass funnel. The product was washed successively with tetrahydrofuran and n-hexane and then dried under vacuum for 12 h to obtain a pale yellow powdered COF-TH material (20.2 mg), with a yield of 87.3%.

[0060] The schematic diagram of the synthesis route of the COF-TH material obtained in this example is shown below. Figure 2 As shown, the Fourier transform infrared spectrum is as follows: Figure 4 As shown, the powder X-ray diffraction pattern is as follows: Figure 6As shown, the solid-state carbon NMR spectrum is as follows: Figure 8 As shown, the nitrogen adsorption-desorption curves are as follows: Figure 10 As shown, the transmission electron microscope (TEM) is as follows: Figure 12 As shown, the thermogravimetric analysis curve is as follows: Figure 14 As shown in the figure, the prepared COF-TH material has a rod-like structure with a crystalline framework, regular and ordered channels, and good thermal stability.

[0061] Example 5

[0062] Palladium acetate (7.5 mg, 0.033 mmol), dichloromethane (10 mL), and COF-TH (20 mg) obtained in Example 4 were sequentially added to a 25 mL round-bottom flask. The mixture was stirred continuously at room temperature for 24 hours. Subsequently, the solid generated was collected by centrifugation, washed with excess dichloromethane, and vacuum dried for 6 h to obtain a yellow powdery Pd@COF-TH composite material.

[0063] The powder X-ray diffraction pattern of the Pd@COF-TH material obtained in this example is as follows: Figure 6 As shown, the nitrogen adsorption-desorption curves are as follows: Figure 10 As shown, the transmission electron microscope (TEM) is as follows: Figure 12 As shown in the figure, the results above indicate that, compared with COF-TH material, Pd@COF-TH material retains its crystallinity but has a reduced specific surface area.

[0064] Example 6

[0065] Potassium carbonate (138 mg, 1 mmol), styrene (69 μL, 0.6 mmol), iodobenzene (56 μL, 0.5 mmol), and N,N-dimethylformamide (1 mL) were sequentially added to a 10 mL Schlenk tube. While stirring, 4 mg of catalyst (at least one of COF-BH, Pd@COF-BH, COF-TH, and Pd@COF-TH) was added. The tube was then evacuated and backfilled with nitrogen three times. o After stirring at C for 24 h and cooling to room temperature, 52 μL (0.5 mmol) of 1,1,2,2-tetrachloroethane was added, followed by filtration. A suitable amount of solution was then subjected to 1H NMR spectroscopy analysis. Figure 15 It can be seen that, after reacting at 120°C for 24 h, the conversion rates of the coupling reaction between iodobenzene and styrene catalyzed by COF-BH, Pd@COF-BH, COF-TH and Pd@COF-TH are <1%, 99%, <1% and 73%, respectively.

[0066] Example 7

[0067] The Pd@COF-BH (4 mg), potassium carbonate (138 mg, 1 mmol), styrene (69 μL, 0.6 mmol), different iodobenzene substrates (0.5 mmol), and N,N-dimethylformamide (1 mL) obtained in Example 3 were sequentially added to a 10 mL Schlenk tube. The tube was then evacuated and backfilled with nitrogen three times. The solution was then heated to 120 °C. o After stirring at C for 24 h or 48 h, the mixture was cooled to room temperature, and 1,1,2,2-tetrachloroethane (52 μL, 0.5 mmol) was added. The mixture was then filtered, and an appropriate amount of the solution was taken for 1H NMR spectroscopy analysis.

[0068] The conversion rates of iodobenzene substrates catalyzed by Pd@COF-BH materials in different Heck reactions are as follows: Figure 16 As shown, the conversion rate of Pd@COF-BH material for iodobenzene substrates containing electron-donating and electron-withdrawing groups can reach over 90%, indicating that Pd@COF-BH material has broad application prospects in the field of heterogeneous catalysis and can be applied to multiple fields such as biomedicine and green chemistry.

Claims

1. A nitrogen-rich acylhydrazone-based covalent organic framework material, characterized in that: The general structural formula of the nitrogen-rich acylhydrazone-based covalent organic framework material is: , At least one of the following: X is independently selected from hydrogen, alkyl, alkoxy, hydroxy, cyano, nitro, mercapto, and halogen; R is independently selected from hydrogen, alkyl, and alkoxy.

2. A method for preparing a nitrogen-rich acylhydrazone-based covalent organic framework material as described in claim 1, characterized in that, Includes the following steps: The nitrogen-rich acylhydrazone covalent organic framework material is obtained by reacting tribenzoylhydrazine monomer with an aromatic aldehyde monomer via a Schiff base reaction; wherein, the general structural formula of the tribenzoylhydrazine monomer is as follows: Wherein, X is independently selected from one of hydrogen, alkyl, alkoxy, hydroxy, cyano, nitro, mercapto, and halogen; R is independently selected from one of hydrogen, alkyl, and alkoxy; the general structural formula of the aromatic aldehyde monomer is: X, Y, and Z are each independently selected from at least one of carbon and nitrogen atoms.

3. The preparation method according to claim 2, characterized in that: The pyromellitic hydrazide monomer is .

4. The preparation method according to claim 3, characterized in that: The method for preparing the tribenzoylhydrazine monomer includes: Dimethyl 3,3''-dimethoxy-5'-(3-methoxy-4-(methoxycarbonyl)phenyl)-[1,1':3',1''-terphenyl]-4,4''-dicarboxylate, hydrazine hydrate, ethanol, and toluene were mixed and then stirred under reflux to obtain the final product.

5. The preparation method according to claim 2, characterized in that: The aromatic aldehyde monomer is , At least one of them.

6. The preparation method according to claim 2, characterized in that: The molar ratio of tribenzoyl hydrazine monomer to aromatic aldehyde monomer in the Schiff base reaction system is 1:

1.

7. The preparation method according to claim 2, characterized in that: The Schiff base reaction system is at a temperature of 120~150°C. o C, the reaction time is 3 to 5 days.

8. The application of a nitrogen-rich acylhydrazone-based covalent organic framework material as described in claim 1 in the catalytic Heck reaction.

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