Use of a covalent organic framework material in the detection of explosive molecules

Abstract

The application discloses an application of a covalent organic framework material in explosive molecule detection, in the application, the covalent organic framework material COFs based on an aggregation-induced emission effect is synthesized, and is called JUC-646, and TNP is taken as a model molecule for research, and effective detection of the explosive by the fluorescent molecule is explored. Meanwhile, the application takes o-dinitrobenzene, m-dinitrobenzene and p-dinitrobenzene as contrast samples, and the specific recognition of JUC-646 to the TNP molecule is verified.

Description

Technical Field

[0001] This invention relates to the field of organic materials applications, specifically to the application of a covalent organic framework material in the molecular detection of explosives. Background Technology

[0002] Rapid detection of explosives is a crucial component of public safety and an important research topic in forensic medicine. 2,4,6-Trinitrophenol (TNP), commonly known as picric acid (PA), is a common explosive. Compared to 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT), TNP has a stronger explosive power and was historically used on a large scale. TNP is highly toxic to organisms, irritating the eyes and skin, causing liver dysfunction, harming the urinary, respiratory, and gastrointestinal systems, and even leading to anemia and cancer. TNP is highly acidic, water-soluble, and its electron-deficient nature makes it difficult to degrade in biological systems and the environment. Widely used in fireworks and match manufacturing, the dye industry, and pharmaceuticals, TNP accumulates in soil and natural water bodies as industrial spills and waste during production, transportation, use, and storage, and has now become a major component of environmental pollutants. Therefore, developing detection methods specifically for TNP is essential. Summary of the Invention

[0003] In view of this, the purpose of this invention is to propose the application of a covalent organic framework material in the molecular detection of explosives.

[0004] The technical solution adopted is as follows:

[0005] Application of a covalent organic framework material in the molecular detection of explosives.

[0006] Furthermore, the covalent organic framework material is prepared by the following method, including the following steps:

[0007] 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.

[0008] 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 place it in an oven to heat.

[0009] 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.

[0010] 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, 0.4-0.6 parts by volume of 1,4-dioxane and 0.1-0.2 parts by volume of 6M acetic acid are added, wherein the weight parts: volume parts = g:mL.

[0011] Further, in S1, 0.037g of TPTPE and 0.031g of BMTA were weighed and added to a mortar and ground thoroughly. Then, 0.5mL of mesitylene, 0.5mL of 1,4-dioxane and 0.1mL of 6M acetic acid were added.

[0012] Furthermore, in S1, it is then inserted into a Pyrex tube with an inner diameter of 8±0.5mm.

[0013] Furthermore, in S2, it is placed in an oven at 120°C and heated for 120 hours.

[0014] Furthermore, in S3, the solvent was exchanged three times with 35 mL of fresh acetone.

[0015] Furthermore, in S3, the product is placed in a vacuum drying oven and dried at 120°C for 12 hours.

[0016] Furthermore, the explosive molecule is 2,4,6-trinitrophenol.

[0017] Furthermore, the explosive molecules are o-dinitrobenzene, m-dinitrobenzene, or p-dinitrobenzene.

[0018] The beneficial effects of this invention are as follows:

[0019] In the application of a covalent organic framework material in the molecular detection of explosives, this invention synthesizes a covalent organic framework material (COF) based on aggregation-induced emission effect, named JUC-646, and uses TNP as the model molecule to explore the effective detection of explosives by fluorescent molecules.

[0020] Meanwhile, using ortho-dinitrobenzene, m-dinitrobenzene, and p-dinitrobenzene as comparative samples, this invention verifies the specific recognition of TNP molecules by JUC-646. Attached Figure Description

[0021] Figure 1 A schematic diagram of the structure for preparing JUC-646.

[0022] Figure 2 Comparison of a) the double-penetrating PXRD of JUC-646 and b) the non-penetrating PXRD of JUC-646.

[0023] Figure 3PXRD images showing the double penetration and non-penetration contrast of JUC-646.

[0024] Figure 4 This is the ultraviolet-visible (UV-VIS) absorption spectrum of JUC-646.

[0025] Figure 5 This is the solid-state fluorescence emission spectrum of JUC-646.

[0026] Figure 6 a) fluorescence emission spectrum and b) Stern- spectroscopy of JUC-646 (c = 60 μg mL⁻¹) after titration with a methanol solution of o-dinitrobenzene (0.001 M). picture.

[0027] Figure 7 a) fluorescence emission spectrum and b) Stern- spectroscopy of JUC-646 (c = 60 μg mL⁻¹) after titration with a methanol solution of m-dinitrobenzene (0.001 M). picture.

[0028] Figure 8 The fluorescence emission spectrum and spectral density (S) of JUC-646 (c = 60 μg mL⁻¹) after titration with a methanol solution of dinitrobenzene (0.001 M) were analyzed. picture.

[0029] Figure 9 a) fluorescence emission spectrum and b) Stern- spectroscopy of JUC-646 (c = 60 μg mL⁻¹) after titration with a methanol solution of 2,4,6-trinitrophenol (0.001 M). picture.

[0030] Figure 10 A comparison chart of the quenching rates of JUC-646 in the titration of nitroaromatic compounds. Detailed Implementation

[0031] 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.

[0032] Example 1

[0033] The preparation method of the covalent organic framework material JUC-646 includes the following steps:

[0034] 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%).

[0035] The obtained covalent organic framework material JUC-646, structure see [link to relevant documentation]. Figure 1 As shown.

[0036] 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.

[0037] Example 2

[0038] 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.

[0039] Example 3

[0040] See Figure 4 and Figure 5 The experimentally obtained UV-Vis absorption spectrum and solid-state fluorescence emission spectrum of JUC-646 are shown below. Figure 4 The spectrum shown indicates that the maximum absorption wavelength of the JUC-646 bulk solid powder is at 338 nm.

[0041] To investigate the fluorescence properties of JUC-646, this invention employed fluorescence analysis to test JUC-646. For example... Figure 5As shown, under light excitation at a wavelength of 341 nm, the bulk JUC-646 powder exhibited a maximum emission peak at 547 nm, and JUC-646 emitted a yellow light.

[0042] Example 4

[0043] See Figures 6-9 As shown in the fluorescence emission spectra, the MeOH methanol solution of TNP exhibits a significant fluorescence quenching effect on the JUC-646 solution, while o-dinitrobenzene, m-dinitrobenzene, and p-dinitrobenzene do not cause significant fluctuations in the fluorescence intensity of the JUC-646 solution. Under light excitation at λex = 341 nm, titration of the JUC-646 solution (c = 60 μg mL⁻¹) with an ethanol solution of TNP (0.001 M, EtOH) revealed that the fluorescence emission intensity of the JUC-646 solution decreased significantly with increasing TNP concentration. After titration with o-dinitrobenzene, m-dinitrobenzene, and p-dinitrobenzene, the fluorescence intensity of JUC-646 only showed slight fluctuations, without significant fluorescence quenching. This indicates that JUC-646 has excellent specific recognition of TNP.

[0044] From the above Stern- The figure shows a good linear relationship between the fluorescence intensity of JUC-646 and the concentration of TNP, while the linear correlation with the concentrations of o-dinitrobenzene, m-dinitrobenzene, and p-dinitrobenzene is relatively weak. A quantitative study on the relationship between the fluorescence intensity of JUC-646 and the concentrations of o-dinitrobenzene, m-dinitrobenzene, p-dinitrobenzene, and TNP was conducted based on Stern... Equation: I0 / I=1+K SV [Q], the quenching constant K of TNP titration with JUC-646 can be calculated. SV =6.995×10 4 M -1 Much larger than 771M -1 (o-dinitrobenzene), 3.96 × 10³ M -1 (m-Dinitrobenzene), 2.58 × 10³ M -1 (p-Dinitrobenzene). Where: I0 is the initial fluorescence emission intensity of JUC-646 without the addition of the nitroaromatic compound; I is the fluorescence emission intensity of JUC-646 after the addition of the nitroaromatic compound; Q is the concentration of the added nitroaromatic compound; K SV The quenching constant of JUC-646 was determined for titration of nitroaromatic compounds. The results calculated above indicate that JUC-646 can be used for the fluorescence detection of TNP.

[0045] Example 5

[0046] See Figure 10 The chart showing the comparison of the quenching rates of JUC-646 by titrating nitro aromatic compounds reveals that the fluorescence intensity of JUC-646 before and after fluorescence quenching was processed to obtain the quenching rate of each nitro aromatic compound for JUC-646. By comparing the quenching rates, it is clear that TNP's quenching rate for JUC-646 is higher than that of other nitro compounds, reaching 95.4%, indicating that JUC-646 has specific recognition of the TNP molecule.

[0047] In summary, this invention, through fluorescence testing of JUC-646, detected various nitroaromatic compounds (o-nitrophenol, m-nitrophenol, p-nitrophenol, and TNP), and observed fluorescence quenching under the influence of TNP molecules, demonstrating its high sensitivity for TNP detection. This invention represents a successful attempt to construct novel AIE-based COF materials. This invention may provide new inspiration and insights for the design and synthesis of future novel AIE-based COF molecules.

[0048] 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. The application of a covalent organic framework material in the detection of explosive molecules, wherein the explosive molecule is 2,4,6-trinitrophenol, the covalent organic framework material specifically recognizes 2,4,6-trinitrophenol, and the covalent organic framework material is prepared by the following method, comprising the following steps: 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. Grind them thoroughly until the powder is uniformly mixed. Then, put them into a tube and 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 acetic acid; wherein the weight parts: volume parts = g:mL; 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 place it in an oven to heat. S3. The product is separated by centrifugation, during which acetone is used to exchange the solvent and wash the precipitate to remove guest molecules in the pores. The product is then placed in a vacuum drying oven and dried under vacuum to obtain a yellow powder. The molecular structural formula of the covalent organic framework material is as follows: ， The molecular structure of BMTA is: ， The molecular structure of TPTPE is: 。 2. The application according to claim 1, 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.

3. The application according to claim 2, characterized in that, In S1, it is then inserted into a Pyrex tube with an inner diameter of 8±0.5 mm.

4. The application according to claim 1, characterized in that, In S2, it is heated in an oven at 120 ℃ for 120 hours.

5. The application according to claim 1, characterized in that, In S3, the solvent was exchanged three times with 35 mL of fresh acetone.

6. The application according to claim 1, characterized in that, In S3, the product is placed in a vacuum drying oven and dried at 120°C for 12 hours.

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