A covalent organic framework material and a method of preparing the same

Abstract

The application discloses a kind of covalent organic framework materials and preparation method thereof, and preparation method includes the following steps: S1.TPTPE and BMTA are weighed and added to mortar and ground thoroughly, to powder is mixed uniformly, then loaded into tube, then add mesitylene, 1,4-dioxane and acetic acid;S2.tube is rapidly frozen under liquid nitrogen bath, vacuum to the pressure in tube to 13-17mmHg, flame sealing, then placed in oven and heated;S3.product is separated by centrifugation, solvent is exchanged with acetone during this period, precipitate is washed to remove guest molecules in channel, product is placed in vacuum drying oven and vacuum dried, to obtain yellow powder product.The covalent organic framework material prepared by the application has a double-penetrating pts topological structure, and has high thermal stability and good porosity.

Description

Technical Field

[0001] This invention relates to the field of organic materials, specifically to a covalent organic framework material and its preparation method. Background Technology

[0002] Covalent organic frameworks (COFs) are a novel type of crystalline porous material composed of light elements such as hydrogen, carbon, nitrogen, boron, and oxygen. The organic monomers within the framework are bonded together by covalent bonds, constructing a stable crystalline framework. After years of development, COFs have shown great potential for applications in gas adsorption and separation, sensing elements, photoelectrocatalysis, proton conduction, drug delivery, and energy storage. The development of COFs continues to expand, with many new topological COFs emerging and gradually moving towards functionalization. In the field of fluorescence sensing, several research groups have reported novel COFs based on the aggregation-induced emission (AIE) effect, fully demonstrating the potential applications of COFs in AIE. Summary of the Invention

[0003] In view of this, in order to solve the above-mentioned technical problems, the purpose of this invention is to propose a covalent organic framework material and its preparation method, which has high thermal stability and good porosity.

[0004] The technical solution adopted is as follows: A method for preparing a covalent organic framework material includes the following steps: S1. Weigh TPTPE and BMTA and add them to a mortar and grind them thoroughly until the powder is uniformly mixed. Then, put them into a tube and add trimethylbenzene, 1,4-dioxane and acetic acid. S2. Quickly freeze the tube in a liquid nitrogen bath, evacuate the tube until the internal pressure reaches 13-17 mmHg, seal it with a flame, and then heat it in an oven. S3. The product is separated by centrifugation, during which the solvent is exchanged with acetone, the precipitate is washed to remove guest molecules in the pores, and the product is placed in a vacuum drying oven for vacuum drying to obtain a yellow powder product.

[0005] Further, in S1, 0.02-0.05 parts by weight of TPTPE and 0.02-0.05 parts by weight of BMTA are weighed and added to a mortar and ground thoroughly. Then, 0.4-0.6 parts by volume of mesitylene and 0.4-0.6 parts by volume of BMTA are added. The volume parts are 1,4-dioxane and 0.1-0.2 volume parts of 6M acetic acid, wherein the weight parts: volume parts = g:mL.

[0006] Further, in S1, 0.037 g of TPTPE and 0.031 g of BMTA were weighed and added to a mortar and ground thoroughly. Then, 0.5 mL of mesitylene, 0.5 mL of 1,4-dioxane and 0.1 mL of 6M acetic acid were added.

[0007] Furthermore, in S1, it is then inserted into a Pyrex tube with an inner diameter of 8±0.5 mm.

[0008] Furthermore, in S2, the sample is heated in an oven at 120 °C for 120 hours.

[0009] Furthermore, in S3, the solvent was exchanged three times with 35 mL of fresh acetone.

[0010] Furthermore, in S3, the product is placed in a vacuum drying oven and dried at 120 °C for 12 hours.

[0011] The present invention provides a covalent organic framework material, which is prepared by the preparation method described in any of the above schemes.

[0012] The beneficial effects of this invention are as follows: This invention synthesizes a covalent organic framework material (COF) based on aggregation-induced emission effect, named JUC-646. JUC-646 has a double-through-pts topology and exhibits high thermal stability and good porosity. Attached Figure Description

[0013] Figure 1 A schematic diagram of the structure for preparing JUC-646.

[0014] Figure 2 Comparison of a) the double-penetrating PXRD of JUC-646 and b) the non-penetrating PXRD of JUC-646.

[0015] Figure 3 PXRD images showing the double penetration and non-penetration of JUC-646.

[0016] Figure 4 The experimental values ​​for JUC-646 are compared with those obtained through Pawley refinement and simulation.

[0017] Figure 5 The N2 adsorption-desorption curve of JUC-646 is shown.

[0018] Figure 6 This is a pore size distribution diagram for JUC-646.

[0019] Figure 7 The BET linear graph for JUC-646.

[0020] Figure 8This is a SEM image of JUC-646.

[0021] Figure 9 Fourier transform infrared spectra of TPTPE (black), BMTA (red), and JUC-646 (blue).

[0022] Figure 10 This is the solid-state carbon NMR spectrum of JUC-646.

[0023] Figure 11 The figure shows the results of the thermogravimetric analysis experiment of JUC-646. Detailed Implementation

[0024] The present invention will be described in detail below through specific embodiments. However, the uses and purposes of these exemplary embodiments are only for illustrating the present invention and do not constitute any limitation on the actual protection scope of the present invention, nor are they intended to limit the protection scope of the present invention to these embodiments. Example 1

[0025] The preparation method of the covalent organic framework material JUC-646 includes the following steps: TPTPE (0.06 mmol, 0.037 g) and BMTA (0.050 mmol, 0.031 g) were weighed and ground thoroughly in a mortar until the powder was homogeneous. The mixture was then placed into a Pyrex tube with an inner diameter of approximately 8 mm. 0.5 mL of trimethylbenzene, 0.5 mL of 1,4-dioxane, and 0.1 mL of 6M acetic acid were added. The Pyrex tube was rapidly frozen in a liquid nitrogen bath (77 K), evacuated to a pressure of 15 mmHg, and flame-sealed to reduce its length to 13 cm. It was then heated in an oven at 120 °C for 120 hours. The product was separated by centrifugation, during which the solvent was exchanged three times with fresh acetone (35 mL) to wash the precipitate and remove guest molecules from the pores. The product was then vacuum-dried at 120 °C for 12 hours, yielding a yellow powder (0.050 g, 76%).

[0026] The obtained covalent organic framework material JUC-646, structure see [link to relevant documentation]. Figure 1 As shown.

[0027] In this embodiment, BMTA is 3,3',5,5'-tetra(p-aminophenyl)-trimethylbenzene. TPTPE is tetra-(4-aldehyde-(1,1-biphenyl))ethylene. Figure 1 The molecular structures of BMTA and TPTPE are shown. Example 2

[0028] The structure of JUC-646 was simulated using the Material Studio software based on a double-penetrating and non-penetrating PTS topology network. Figure 2 The PXRD of the simulated structure was compared with the PXRD obtained from experimental testing. Figure 3 As can be seen, the experimental values ​​are in good agreement with the double penetration mode, thus confirming that JUC-646 has a double penetration PTS topology. Example 3

[0029] After geometric energy minimization using the Material Studio software based on a double-through PTS topology network, the cell parameters of JUC-646 (space group P1, cell parameters a = b = 25.200 Å, c = 49.600 Å, α = β = γ = 120°) were obtained. Figure 4 It can be seen that the experimental results are in good agreement with the simulation results. The experimental data of the activated sample were refined by full-profile mode matching Pawley refinement. After refinement, the PXRD of JUC-646 corresponds to the (100), (012), (021) and (220) Bragg peaks at 2θ=3.51, 5.00, 7.23 and 9.94 respectively. According to the Pawley refinement results of PXRD, the cell parameters of JUC-646 are basically consistent with the cell parameters of the simulated structure (a = 24.8742 Å, b = 25.0964 Å, c = 49.2124 Å, α = 87.9905, β = 88.1970, γ = 91.5287, Rωp = 1.50% and Rp = 1.05%; the specific cell parameters are shown in Table 1).

[0030] Table 1. Cell parameters and partial atomic coordinates of JUC-646 based on the double-through-pts topology.

[0031] Example 4 To further investigate the characteristics of the JUC-646 pores, nitrogen adsorption-desorption tests were conducted at 77 K using ultra-high purity nitrogen (purity >99.9999%). Figure 5As shown, the adsorption isotherm reveals a rapid gas absorption in the low-pressure region (P / P0<0.05), which is consistent with the characteristics of a type I adsorption isotherm for microporous materials. This demonstrates the microporous properties of JUC-646 and indicates that JUC-646 exhibits good adsorption reversibility, as evidenced by the good overlap between the adsorption and desorption curves. Example 5

[0032] The pore size distribution of JUC-646 was calculated using nonlocal density functional theory (NLDFT). The results show that the micropore size of JUC-646 is 1.2 nm, which is in good agreement with the results of its crystal structure simulation. Figure 6 ).

[0033] The specific surface area of ​​JUC-646 was calculated to be 1861 m² using the Brunauer-Emmett-Teller (BET) equation. 2 g -1 When P / P0 = 0.9, the total pore volume of JUC-646 is calculated to be 0.962 cm³. 2 g -1 ( Figure 7 ). Example 6

[0034] Scanning electron microscopy (SEM) analysis of the COFs revealed that JUC-646 consisted of irregular particles around 200 nm in size. Figure 8 ). Example 7

[0035] Fourier transform infrared (FT-IR) spectroscopy showed that the C=O stretching vibration peak of TPTPE disappeared (1700 cm⁻¹), and the nitrogen-hydrogen bond stretching vibration peak of BMTA also disappeared (3310-3400 cm⁻¹). JUC-646 showed a new peak at 1625 cm⁻¹, corresponding to the C=N stretching vibration, indicating the completion of the Schiff base reaction. Figure 9 ). Example 8

[0036] By using solid 13 C-CP / MAS solid-state NMR spectroscopy further confirmed the chemical structure of JUC-646. The spectrum showed five sharp signal peaks at δ = 44, 139, 142, 148, and 157 ppm. Analysis of the signal peak assignments led us to conclude that the peak at 159 ppm belongs to the carbon in the C=N group, indicating the formation of C=N and confirming the consistency of the JUC-646 structure with expectations. Figure 10 ). Example 9

[0037] Thermogravimetric analysis (TGA) shows that JUC-646 remains stable at 430 ℃, and the mass reduction at temperatures close to 500 ℃ is only about 10%, indicating that JUC-646 has excellent thermal stability. Figure 11 ).

[0038] In summary, Example 1 is the design and synthesis experiment of JUC-646, and Examples 2-9 are the characterization experiments of the structure and performance of JUC-646.

[0039] In summary, Example 1 successfully synthesized JUC-646 COFs with a double-penetrating PTS three-dimensional structure.

[0040] In summary, based on the Schiff base reaction of the fluorescent molecule tetra-(4-aldehyde-(1,1-biphenyl))ethylene with an aromatic amine monomer, a microporous COF material JUC-646 exhibiting the AIE effect was successfully prepared via a solvothermal synthesis method. The structure of JUC-646 was determined by PXRD and Fourier transform infrared spectroscopy, and its TGA and nitrogen adsorption-desorption curves were measured. The structure indicates that JUC-646 possesses high thermal stability and good porosity, making it a suitable adsorbent.

[0041] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a covalent organic framework material, characterized in that, Includes the following steps: S1. Weigh TPTPE and BMTA and grind them thoroughly in a mortar until the powder is uniformly mixed. Then, load the mixture into a tube and add mesitylene, 1,4-dioxane, and acetic acid. BMTA is 3,3',5,5'-tetra(p-aminophenyl)-bi-mesitylene, and TPTPE is tetra-(4-aldehyde-(1,1-biphenyl))ethylene. The molecular structures of BMTA and TPTPE are as follows: and ; S2. Quickly freeze the tube in a liquid nitrogen bath, evacuate the tube until the internal pressure reaches 13-17 mmHg, seal it with a flame, and then heat it in an oven. S3. The product is separated by centrifugation, during which the solvent is exchanged with acetone, the precipitate is washed to remove guest molecules in the pores, and the product is placed in a vacuum drying oven for vacuum drying to obtain a yellow powder product.

2. The method for preparing the covalent organic framework material according to claim 1, characterized in that, In S1, weigh 0.02-0.05 parts by weight of TPTPE and 0.02-0.05 parts by weight of BMTA and add them to a mortar and grind them thoroughly. Then add 0.4-0.6 parts by volume of mesitylene, 0.4-0.6 parts by volume of 1,4-dioxane and 0.1-0.2 parts by volume of 6M acetic acid, wherein the weight parts: volume parts = g:mL.

3. The method for preparing the covalent organic framework material according to claim 2, characterized in that, In S1, weigh 0.037 g TPTPE and 0.031 g BMTA and grind them thoroughly in a mortar. Then add 0.5 mL mesitylene, 0.5 mL 1,4-dioxane and 0.1 mL 6M acetic acid.

4. The method for preparing the covalent organic framework material according to claim 3, characterized in that, In S1, it is then inserted into a Pyrex tube with an inner diameter of 8±0.5 mm.

5. The method for preparing the covalent organic framework material according to claim 1, characterized in that, In S2, place it in an oven at 120°C and heat for 120 hours.

6. The method for preparing the covalent organic framework material according to claim 1, characterized in that, In S3, the solvent was exchanged three times with 35 mL of fresh acetone.

7. The method for preparing the covalent organic framework material according to claim 1, characterized in that, In S3, the product was placed in a vacuum drying oven and dried at 120 °C for 12 hours.

8. A covalent organic framework material, characterized in that, It is prepared by any of the preparation methods described in claims 1-7.

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