Preparation method of organic framework material based on boron-nitrogen dynamic covalent bonds

Abstract

The invention discloses a preparation method of an organic framework material based on a boron-nitrogen dynamic covalent bond, which comprises the following steps of: obtaining a functional group modified boron-containing molecule 4, 7-bis (benzo [d] [1, 3, 2] boron dioxide heterocycle-2-yl) benzo [c] [1, 2, 5] thiadiazole and a nitrogen-containing molecule tris (4-(4-pyridyl) phenyl) amine through a series of organic synthesis means, and synthesizing the functional group modified boron-containing molecule 4, 7-bis (benzo [d] [1, 3, 2] boron dioxide heterocycle-2-yl) benzo [c] [1, 2, 5] thiadiazole. The organic framework material constructed by dynamic covalent bonds has excellent photocatalytic H2O2 generation capability. The invention provides a new scheme for adjusting the exciton-related properties of the organic polymer so as to improve the photocatalytic performance, and has potential application prospects in solar energy conversion and photocatalysis.

Description

Technical Field

[0001] The present invention belongs to the technical field of dynamic covalent bond materials, and particularly relates to a preparation method of an organic framework material based on boron-nitrogen dynamic covalent bonds. Background Art

[0002] Hydrogen peroxide (H2O2) is an important chemical widely used in multiple industrial fields. However, the current industrial anthraquinone process for synthesizing H2O2 is characterized by high carbon emissions. Photocatalysis and electrocatalysis technologies, with solar energy and renewable electricity as energy inputs, show great potential for the green preparation of H2O2 from oxygen (O2) and water (H2O) (Angew. Chem. Int. Ed. 2024, e202414417). Efficient photogenerated carrier separation is widely regarded as the key to achieving effective photocatalytic solar energy conversion. Although some covalent organic frameworks (COFs) exhibit visible light absorption ability, rapid carrier recombination severely limits their photocatalytic efficiency (Adv. Funct. Mater. 2023, 33, 2307300).

[0003] Therefore, exploring new methods to regulate exciton dissociation in the framework is of great significance for promoting the development of photocatalysis. Research shows that boron-nitrogen B←N dynamic covalent bonds can effectively inhibit exciton effects in organic conjugated semiconductors, thus providing a simple solution for photocatalysis (Angew. Chem. Int. Ed. 2024, e202417712). In this context, coordination B←N frameworks, as a new type of material, have gradually become the focus of research. As early as 2011, Severin et al. first proposed the concept of organic frameworks based on B←N coordination bonds. Although there were certain challenges in the stability of this type of framework at that time, this pioneering research laid an important foundation for the application of B←N dynamic covalent bonds in organic framework materials (Angew. Chem. Int. Ed. 2011, 50, 3034 - 3037). The binding energy of the B←N bond is about 100 kJ / mol, much higher than that of traditional hydrogen bonds (usually between 10 - 40 kJ / mol), which makes B←N dynamic covalent bonds have greater potential in enhancing the structural stability of the framework and maintaining porosity. Summary of the Invention

[0004] The purpose of the present invention is to avoid the deficiencies of the prior art and provide a preparation method of an organic framework material based on boron-nitrogen B←N dynamic covalent bonds.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A preparation method of an organic framework material based on boron-nitrogen B←N dynamic covalent bonds, which comprises the following steps:

[0007] S1: Synthesize 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole, and the synthesis route is as follows:

[0008] At room temperature, add 4,7-diboron pinacol ester-2,1,3-benzothiadiazole and sodium periodate respectively, then add the solvents tetrahydrofuran and water under a nitrogen atmosphere, stir evenly and then add dilute hydrochloric acid to react. Evaporate and filter the reaction product to obtain Product 1, that is, benzo[c][1,2,5]thiadiazole-4,7-diyl diboronic acid; then add catechol and toluene, ultrasonically disperse and heat the solution to 100-110 °C. After the reaction is completed, perform suction filtration and washing to obtain Product B, that is, 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole.

[0009]

[0010] S2: React 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole with tris(4-(4-pyridyl)phenyl)amine in the presence of toluene, and perform suction filtration and washing on the reaction product to obtain the organic framework material DOF based on the boron-nitrogen B←N dynamic covalent bond.

[0011]

[0012] Furthermore, the specific steps of the synthesis method of the monomer molecule 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole (B) are as follows:

[0013] Step 1: Add 4,7-diboron pinacol ester-2,1,3-benzothiadiazole and sodium periodate to the container in sequence, add the solvents tetrahydrofuran and water in proportion under a nitrogen atmosphere, stir at room temperature for 0.5-1 hour, and then add 1-2 mol L -1 dilute hydrochloric acid and react for another 18-24 hours; after the reaction is completed, remove the solvent tetrahydrofuran with a rotary evaporator and then perform suction filtration to obtain the filter residue. Wash the filter residue with water, n-heptane and ether 2-4 times to obtain the crude product, and then place it in a vacuum environment at 50-60 °C for 12-24 hours. Cool the obtained solid to room temperature to obtain Product 1, that is, benzo[c][1,2,5]thiadiazole-4,7-diyl diboronic acid;

[0014] Step 2: Add Product 1 to a eggplant-shaped flask, add catechol and toluene in sequence, then ultrasonically disperse the solid evenly in the solvent toluene for 10-20 min, then heat the solution to 100-110 °C, and place about half full in a Dean-Stark apparatus The molecular sieve is used for water removal; after reacting for 18 - 24 hours, it is cooled to room temperature for 1 - 2 hours, and gray crystals gradually precipitate. The filter residue is obtained by suction filtration, and the filter residue is washed 2 - 4 times with acetonitrile and dichloromethane respectively to obtain the crude product. Then, it is placed in a vacuum environment at 40 - 50 °C for 12 - 24 hours, and the obtained solid is cooled to room temperature to obtain product B, namely 4,7 - bis(benzo[d][1,3,2]dioxaborol - 2 - yl)benzo[c][1,2,5]thiadiazole.

[0015] Further, in step 1, 4,7 - bis(pinacolboronate)-2,1,3 - benzothiadiazole and sodium periodate are added in a molar ratio of 1:6; the addition amount of 1 - 2 mol L -1 of dilute hydrochloric acid and the molar ratio of 4,7 - bis(pinacolboronate)-2,1,3 - benzothiadiazole is 3:1.

[0016] Further, the heating of the solution is carried out under the condition of a constant - temperature oil bath.

[0017] Further, in step S2, the monomer molecule 4,7 - bis(benzo[d][1,3,2]dioxaborol - 2 - yl)benzo[c][1,2,5]thiadiazole and tris(4 - (4 - pyridyl)phenyl)amine are added in proportion to toluene with a volume of 5 - 10 mL, and ultrasonic treatment is carried out for 10 - 20 minutes to uniformly disperse the solid in toluene. Then, it is heated to 80 - 90 °C and reacted for 12 - 24 hours. During this period, yellow solids precipitate in toluene, and the filter residue obtained after filtration is the organic framework material based on the boron - nitrogen B←N dynamic covalent bond;

[0018] Further, the molar ratio of the monomer molecule 4,7 - bis(benzo[d][1,3,2]dioxaborol - 2 - yl)benzo[c][1,2,5]thiadiazole to tris(4 - (4 - pyridyl)phenyl)amine is 3:2.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] Through a series of organic synthesis means, the boron - containing molecule 4,7 - bis(benzo[d][1,3,2]dioxaborol - 2 - yl)benzo[c][1,2,5]thiadiazole modified with functional groups and the nitrogen - containing molecule tris(4 - (4 - pyridyl)phenyl)amine are obtained. The organic framework material constructed by dynamic covalent bonds has excellent photocatalytic H2O2 generation ability. The present invention provides a new scheme for regulating the exciton - related properties of organic polymers to improve photocatalytic performance, and has potential application prospects in solar energy conversion and photocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the photocatalytic hydrogen peroxide performance diagram of the organic framework material prepared in the embodiment of the present invention;

[0022] Figure 2 is the 1H NMR spectrum of the monomer molecule B two-dimensional material prepared in the embodiment of the present invention;

[0023] Figure 3 is the PXRD experimental pattern of the organic framework material prepared in the embodiment of the present invention;

[0024] Figure 4 is the TEM image of the organic framework material prepared in the embodiment of the present invention. Detailed implementation manners

[0025] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0026] Example 1

[0027] The monomer molecule 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole was synthesized as follows:

[0028] Step 1: Add 1 g of 4,7-diboron pinacol ester-2,1,3-benzothiadiazole to a 50 mL Schlenk flask. Under a nitrogen atmosphere, successively add 16 mL of tetrahydrofuran and 4 mL of water, and then return to room temperature and react for 0.5 hour. Then add 4 mL of 1 mol / L -1 dilute hydrochloric acid, react for 24 hours, remove the solvent tetrahydrofuran with a rotary evaporator, and then filter. The filter cake is washed three times with 100 mL of water, n-heptane, and ether respectively. The washed solid is placed in a vacuum environment at 60 °C for 12 hours and then cooled to room temperature to obtain 547 mg of benzo[c][1,2,5]thiadiazole-4,7-diyl diboronic acid, which is a pale yellow solid with a yield of 94.9%.

[0029] Step 2: Add 200 mg of benzo[c][1,2,5]thiadiazole-4,7-diyl diboronic acid and 210 mg of catechol into a 50 mL eggplant-shaped flask, add 15 mL of toluene, and then ultrasonicate for 10 min. Then heat the solution to 100 - 110 °C and place about half-full of The molecular sieve was used to remove water. The eggplant-shaped flask was cooled to room temperature for 1 hour after reacting for 18 hours, and gray solid gradually precipitated. The filtrate was obtained by suction filtration. The filter residue was washed 3 times with 50 mL of acetonitrile and then placed in a vacuum environment at 40 °C for 12 hours. The obtained solid was cooled to room temperature to obtain the target product B2. The product B1 was specifically 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole.

[0030] The specific steps for the preparation method of the organic framework material (DOF) based on B←N dynamic covalent bonds are as follows:

[0031] 7.4 mg of the monomer molecule 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole and 6.7 mg of tris(4-(4-pyridyl)phenyl)amine were added to 10 mL of toluene. After ultrasonic treatment for 10 min to uniformly disperse the solid in toluene, it was heated to 90 °C and reacted for 24 hours. During this period, yellow solid precipitated in toluene. After filtration, 10.6 mg of the filter residue was obtained, which was the involved DOF material with a yield of 75.2%.

[0032] Example 2

[0033] For the organic framework material (DOF) based on boron-nitrogen B←N dynamic covalent bonds, the specific steps for the photocatalytic hydrogen peroxide method are as follows:

[0034] 5 mg of the organic framework material (DOF) based on boron-nitrogen B←N dynamic covalent bonds was added to a conical flask containing 50 mL of deionized water and then ultrasonicated for 10 min to uniformly disperse it in water. Then, the conical flask was wrapped with tin foil. While shielding from light for 1 h, high-purity oxygen was introduced into the water. After that, the wrapped tin foil was removed, the introduction of high-purity oxygen was stopped, and the conical flask was irradiated with a 400 W xenon lamp. Then, every 0.5 h, the generation and content of hydrogen peroxide were monitored by the iodometric method. The results were that the yield corresponding to 0.5 h was 1021 μmol g -1 , and the yield corresponding to 1 h was 2013 μmol g -1 .

[0035] The test results of the photocatalytic hydrogen peroxide performance of the DOF material are shown in Figure 1 , and it can be seen that the DOF material has excellent photocatalytic H2O2 generation ability.

[0036] The nuclear magnetic resonance hydrogen spectrum of the monomer molecule B involved in the present invention is shown in Figure 2 .

[0037] The PXRD of the DOF material is shown in Figure 3 . From the relatively small full width at half maximum and relatively strong signal of the XRD signal, it can be seen that the DOF material has good crystallinity.

[0038] TEM electron micrograph of the DOF material, high resolution, and full-curve electron diffraction are shown in Figure 4 .

[0039] It should be noted that the embodiments described above are only the preferred embodiments of the present invention. For those of ordinary skill in the art, without departing from the principle of the present invention, several modifications, improvements, and equivalent substitutions can be made to the present invention, and these modifications, improvements, and equivalent substitutions are also considered to fall within the protection scope of the claims of the present invention.

Claims

1. A preparation method of an organic framework material based on boron-nitrogen B←N dynamic covalent bonds, characterized in that, It includes the following steps: S1: Synthesize 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole, and the synthetic route is as follows: At room temperature, add 4,7-diboronopinanediol ester-2,1,3-benzothiadiazole and sodium periodate respectively, then add the solvent tetrahydrofuran and water in a nitrogen environment, stir evenly and then add dilute hydrochloric acid to react. Evaporate and filter the reaction product to obtain Product 1, namely benzo[c][1,2,5]thiadiazole-4,7-diyl diboronic acid; then add catechol and toluene, disperse ultrasonically and heat the solution to 100-110 °C. After the reaction is completed, perform suction filtration and washing to obtain Product B, namely 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole. S2: React 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole with tris(4-(4-pyridyl)phenyl)amine in the presence of toluene, and filter and wash the reaction product to obtain the organic framework material DOF based on the boron-nitrogen B←N dynamic covalent bond.

2. The preparation method of the organic framework material based on boron nitride B←N dynamic covalent bonds according to claim 1, characterized in that The specific steps of the synthesis method of the monomer molecule 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole (B) are as follows: Step 1: Add 4,7-diboronopinanediol-2,1,3-benzothiadiazole and sodium periodate into a container in sequence according to the proportion. Then add the solvents tetrahydrofuran and water into the container in nitrogen atmosphere according to the proportion. After stirring at room temperature for 0.5 - 1 hour, add 1 - 2 mol L -1 dilute hydrochloric acid and react for another 18 - 24 hours; After the reaction, remove the solvent tetrahydrofuran with a rotary evaporator, then filter to obtain a filter residue. Wash the filter residue with water, n-heptane and ether 2 - 4 times in sequence to obtain a crude product. Then place the crude product in a vacuum environment at 50 - 60 °C for 12 - 24 hours, and cool the obtained solid to room temperature to obtain Product 1, namely benzo[c][1,2,5]thiadiazole-4,7-diyl diboronic acid; Step 2: Add Product 1 into a round-bottom flask, then successively add catechol and toluene. After that, ultrasonicate for 10 - 20 min to uniformly disperse the solid in the solvent toluene. Then heat the solution to 100 - 110 °C and charge approximately half-full of molecular sieve in a Dean-Stark apparatus to remove water; after reacting for 18 - 24 h, cool to room temperature for 1 - 2 h, and gray crystals gradually precipitate. Filter by suction to obtain the filter residue, wash the filter residue with acetonitrile and dichloromethane for 2 - 4 times to obtain the crude product, and then place it in a vacuum environment at 40 - 50 °C for 12 - 24 h. Cool the obtained solid to room temperature to obtain Product B, i.e., 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole.

3. The preparation method of the organic framework material based on boron-nitrogen B←N dynamic covalent bonds according to claim 1 or 2, characterized in that, In step 1, 4,7-diboronopinanediol ester-2,1,3-benzothiadiazole and sodium periodate are added in a molar ratio of 1:6; the addition amount of 1-2 mol L -1 dilute hydrochloric acid has a molar ratio of 3:1 to 4,7-diboronopinanediol ester-2,1,3-benzothiadiazole.

4. The preparation method of the organic framework material based on boron-nitrogen B←N dynamic covalent bond according to claim 1 or 2, characterized in that, The heating of the solution is carried out under the condition of a constant temperature oil bath.

5. The preparation method of the organic framework material based on boron-nitrogen B←N dynamic covalent bonds according to any one of claims 1 to 4, characterized in that, In step S2, add the monomer molecule 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole and tris(4-(4-pyridyl)phenyl)amine in proportion to toluene with a volume of 5-10 mL, ultrasonically treat for 10-20 minutes to uniformly disperse the solid in toluene, and then heat to 80-90 °C and react for 12-24 hours. During this period, yellow solid precipitates in toluene, and the filter residue obtained after filtration is the organic framework material based on the boron-nitrogen B←N dynamic covalent bond.

6. The preparation method of the framework material (DOF) based on B←N dynamic covalent bonds according to claim 5, characterized in that, The molar ratio of the monomer molecule 4,7-bis(benzo[d][1,3,2]dioxaborol-2-yl)benzo[c][1,2,5]thiadiazole to tris(4-(4-pyridyl)phenyl)amine is 3:2.

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