Fluorescent covalent organic framework material for antibiotic detection as well as preparation method and application of fluorescent covalent organic framework material

Abstract

The invention relates to the technical field of porous material preparation and detection of organic pollutants in a water phase, in particular to a fluorescent covalent organic framework material capable of being used for antibiotic detection and a preparation method and application thereof, and the covalent organic framework material is of a novel sql plane interspersed topological structure. The covalent organic framework material has a three-dimensional framework structure formed by interlocking rare sql two-dimensional planes, has fluorescent properties, is high in stability, can efficiently detect nitrofuran antibiotics in water through an electron transfer mechanism, and can be repeatedly used. According to the preparation method disclosed by the invention, a novel fluorescent covalent organic framework is designed and synthesized, and a covalent organic framework with a plane interpenetrating structure is synthesized and has a fluorescent property. The preparation method is easy to operate, environmentally friendly, low in cost and easy for industrial production. The prepared covalent organic framework is high in stability, and nitrofuran antibiotic pollutants in a water phase can be efficiently detected by combining a fluorescence sensing mechanism.

Description

Technical Field

[0001] The invention relates to the technical field of porous material preparation and organic pollutant detection technology in water phase, and in particular to a fluorescent covalent organic framework material that can be used for antibiotic detection, a preparation method and application thereof. Background Art

[0002] Three-dimensional covalent organic frameworks are a type of crystalline organic porous materials, which usually have the characteristics of low density, high specific surface area, good thermal stability, and functional design. They are currently widely used in gas adsorption, separation, catalysis, sensing, optoelectronic materials, and energy storage. However, the limited structural diversity of three-dimensional covalent organic frameworks and the difficulty in synthesizing highly crystalline samples have hindered the development of three-dimensional covalent organic frameworks. It is of great significance to develop three-dimensional covalent organic frameworks with new structures and explore their synthesis strategies and preparation methods. Framework chemistry shows that the interpenetration of two-dimensional planes to construct three-dimensional covalent organic frameworks is an important method to enrich their structural diversity. In principle, three-dimensional covalent organic framework materials with planar interpenetrating structures can combine the advantages of three-dimensional covalent organic frameworks such as through-holes, rich exposed sites, and nano-sized multi-level pores with the conjugated planes and π-π stacking columns of two-dimensional covalent organic frameworks. In summary, three-dimensional covalent organic framework materials with planar interpenetrating structures have important development prospects. However, there is only one related literature report, mainly because the synthesis strategy of this material is seriously lacking and there is a lack of relevant theoretical guidance.

[0003] With the increasing attention paid to public health and water quality, the demand for the detection and removal of pollutants in wastewater is increasing. Antibiotics are widely used to treat bacterial infections in humans and animals and are an important class of organic pollutants in water bodies. The abuse of antibiotics has led to a large amount of antibiotic residues, and various antibiotics have been detected in surface water, groundwater and drinking water. However, the current detection methods mainly include chromatography and mass spectrometry, which have problems such as complex operation and high instrument cost. The research on new simple and efficient detection methods has important application value and scientific significance. Fluorescence detection is an effective method for effectively detecting low-concentration analytes. The use of covalent organic frameworks for antibiotic detection has the following advantages: First, it is a pure organic material with strong designability. The fluorescence properties can be regulated by molecular element design, and covalent organic framework materials with excellent fluorescence properties can be constructed. Secondly, due to its porosity, the analyte can be enriched in the pores to achieve the amplification of the fluorescence signal, thereby constructing a covalent organic framework material with low detection limit and high sensitivity to the analyte. Finally, the formation mode of covalent bond connection gives it high stability, which meets the requirements of recycling in practical applications. Summary of the invention

[0004] One of the purposes of the present invention is to provide a fluorescent covalent organic framework material that can be used for antibiotic detection, has high stability, can efficiently detect nitrofuran antibiotics in water through an electron transfer mechanism, and can be reused.

[0005] The second object of the present invention is to provide a method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection, which has a simple preparation process and is easy to adjust.

[0006] The third object of the present invention is to provide an application of a fluorescent covalent organic framework material that can be used for antibiotic detection.

[0007] The scheme adopted by the present invention to achieve one of the purposes is: a fluorescent covalent organic framework material that can be used for antibiotic detection, the molecular structure of the covalent organic framework material is The covalent organic framework material is a novel sql plane interlaced topological structure.

[0008] The scheme adopted by the present invention to achieve the second purpose is: a method for preparing the fluorescent covalent organic framework material that can be used for antibiotic detection, dispersing an aldehyde precursor and an amino precursor in a solvent, adding a catalyst, and reacting the obtained mixed system under vacuum or inert atmosphere at 80-160°C. After the reaction is completed, a yellow solid powder is obtained, which is purified and dried to obtain the covalent organic framework.

[0009] Preferably, the amino precursor is The aldehyde precursor is

[0010] Preferably, the solvent is a good solvent, or a solution formed by mixing a good solvent and a poor solvent in any volume ratio: the good solvent is at least one of toluene, chloroform, o-dichlorobenzene, and mesitylene; the poor solvent is at least one of n-hexane, n-butanol, tert-butanol, and isopropanol.

[0011] Preferably, the catalyst is acetic acid.

[0012] Preferably, the molar ratio of the amino precursor, the aldehyde precursor and the catalyst is 1:1:30-150; the concentration of the amino precursor in the mixed system is 0.01-0.1 mol / L, and the concentration of the catalyst is 1-17 mol / L.

[0013] Preferably, the purification process is to use at least one of tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide and dimethyl sulfoxide to Soxhlet extract the solid product, and finally use dichloromethane to Soxhlet extract the solid.

[0014] Preferably, the preparation method of the precursor molecule is as follows: the preparation method of the aldehyde precursor or amino precursor is as follows: the halogenated molecule, phenylboronic acid reagent, catalyst and alkali agent are dispersed in a solvent, and then reacted at 80-120°C under an inert atmosphere. After the reaction is completed, the solvent is removed and purified to obtain a solid product, namely the aldehyde precursor or amino precursor.

[0015] Preferably, the halogenated molecule is N9,N9,N 10 ,N 10 -Tetrakis(4-bromophenyl)anthracene-9,10-diamine or N9,N9,N 10 ,N 10 -tetrakis(4-iodophenyl)anthracene-9,10-diamine, the phenylboronic acid reagent is at least one of 4-formaldehyde phenylboronic acid, 4-formaldehyde phenylboronic acid pinacol ester, 4-aminophenylboronic acid or 4-aminophenylboronic acid pinacol ester, the catalyst is tetrakistriphenylphosphine palladium, the alkali agent is at least one of cesium carbonate, potassium carbonate, sodium carbonate and potassium phosphate, the solvent is at least one of toluene, 1,4-dioxane and N,N-dimethylformamide, and the molar ratio of the halogenated molecule, the phenylboronic acid reagent, the tetrakistriphenylphosphine palladium and the alkali agent is 50:200-500:5:200-500.

[0016] The solution adopted by the present invention to achieve the third purpose is: an application of the fluorescent covalent organic framework material that can be used for antibiotic detection, and applying the covalent organic framework to the fluorescence detection of nitrofuran antibiotics in an aqueous phase.

[0017] The present invention has the following advantages and beneficial effects:

[0018] 1. The covalent organic framework material of the present invention has a rare three-dimensional framework structure formed by the interlocking of two-dimensional SQL planes, and has fluorescent properties and high stability. It can efficiently detect nitrofuran antibiotics in water through an electron transfer mechanism and can be reused.

[0019] 2. The preparation method of the present invention synthesizes a novel fluorescent covalent organic framework by designing and synthesizing a covalent organic framework with a planar interlaced structure and having fluorescent properties. The preparation method is easy to operate, green and environmentally friendly, low in cost, and easy to industrialize.

[0020] 3. The covalent organic framework prepared by the present invention has high stability and can efficiently detect nitrofuran antibiotic pollutants in the aqueous phase in combination with the fluorescence sensing mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The X-ray powder diffraction pattern of the covalent organic framework prepared by the present invention;

[0022] Figure 2a is the PXRD pattern and SEM morphology characterization results of 3D-An-COF, b is the three-dimensional reciprocal lattice of 3D-An-COF;

[0023] Figure 3 Schematic diagram of the covalent organic framework prepared by the present invention, wherein Figure 3 a is a structure where two SQL topology networks are almost vertically interlaced. Figure 3 b is a frame with a two-dimensional interlaced structure. Figure 3 c is the one-dimensional pore structure of the framework;

[0024] Figure 4 The solid fluorescence and antibiotic detection results of the covalent organic framework prepared by the present invention are shown in FIG. Figure 4 a is the solid fluorescent material of the covalent organic framework prepared by the present invention, Figure 4 bd is the fluorescence detection result of nitrofuran antibiotics in the aqueous phase. DETAILED DESCRIPTION

[0025] For a better understanding of the present invention, the following examples are provided to further illustrate the present invention, but the present invention is not limited to the following examples.

[0026] Example 1

[0027] PADA (aldehyde precursor) (8.8 mg, 0.01 mmol) and PADC (amino precursor) (9.3 mg, 0.01 mmol) were dispersed in a mixed solution of toluene and isopropanol (0.9 ml / 0.15 ml), and then 0.105 mL of 15 mol L -1 Acetic acid solution, and finally placed it in an oven at 140°C for 72 hours. After the reaction is completed, a yellow solid powder is obtained. The solid is extracted with tetrahydrofuran and dichloromethane in turn. Finally, the solid is placed in a vacuum environment and heated and dried for standby use. The covalent organic framework material is synthesized as follows; the PADA unit is The PADC primitive is

[0028]

[0029] Figure 1 This is the X-ray powder diffraction pattern of the covalent organic framework prepared in this example. It can be seen from the figure that the covalent organic framework exhibits a series of diffraction peaks in the range of 2-40°, indicating that it has a long-range ordered crystalline structure.

[0030] Figure 2The PXRD pattern of 3D-An-COF is shown. Curve 1 in a represents the experimental XRD pattern, the refined XRD pattern, the difference between the experimental and refined patterns, the Bragg position of the crystal structure and the SEM morphology of the crystal. b is the three-dimensional reciprocal lattice of 3D-An-COF. It can be seen that the reflection conditions indicate that the possible space group is Pccn. According to the standard of I / σ>1, the resolution is limited to It is worth noting that, finally, the Rietveld refinement gives the lattice parameters Among them, Rwp=9.58% and Rp=6.43%.

[0031] Figure 3 It is shown that the covalent organic framework prepared by the present invention is a three-dimensional structure, wherein Figure a is a nearly vertical interlaced structure of two SQL topological networks, Figure b is a framework with a two-dimensional planar interlaced structure, and Figure c is a one-dimensional pore structure of the framework.

[0032] Table 1 shows the 3D-An-COF unit cell parameters and atomic coordinates obtained after Rietveld refinement.

[0033]

[0034]

[0035] Example 2

[0036] The synthesis of PADA in Example 1 is as follows:

[0037]

[0038] Compound 1 (2.00 g, 2.43 mmol), 4-aminophenylboronic acid pinacol ester (2.55 g, 11.65 mmol), tetrakistriphenylphosphine palladium (0.15 g, 0.125 mmol), and potassium carbonate (2.69 g, 19.44 mmol) were placed in a round-bottom flask, and then dioxane solvent (80 mL) was added to disperse it. Then, the mixture was heated at 90°C under nitrogen protection for 3 days. After the reaction was completed, water was added to precipitate the solid, which was filtered and purified by column chromatography to obtain a yellow solid product. 1 H NMR (400M, DMSO-d6, ppm): δ = 8.19 (m, 4H), 7.51 (m, 4H), 7.43 (d, J = 8.8Hz, 8H), 7 .28(d,J=8.6Hz,8H), 7.06(d,J=8.7Hz,8H), 6.60(d,J=8.5Hz,8H), 5.14(s,8H).

[0039] The synthesis of PADC in Example 1 is as follows:

[0040]

[0041] Compound 1 (3.00 g, 3.64 mmol), compound 2 (6.90 g, 21.85 mmol), tetrakistriphenylphosphine palladium (0.21 g, 0.18 mmol), potassium carbonate (4.02 g, 29.12 mmol) were placed in a round-bottom flask, and then a mixed solvent of toluene and water (120 mL / 40 mL) was added to disperse it, and then heated at 100 ° C for 3 days under nitrogen protection. After the reaction was completed, the solvent was removed by rotary evaporation, and then purified by column chromatography to obtain a yellow solid product 3. The product was characterized by nuclear magnetic resonance. 1 H NMR (400MHz, CDCl3, ppm): δ = 8.27 (m, 4H), 7.57 (m, 16H), 7.49 (d, J = 8.7Hz, 8H), 7.44 (m, 4H), 7.24 (d, J =8.7Hz, 8H), 5.44 (s, 4H), 3.81 (d, J = 11.3Hz, 8H), 3.69 (d, J = 10.9Hz, 8H), 1.33 (s, 12H), 0.83 (s, 12H). .

[0042] Trifluoroacetic acid (5 mL) was added to a solution of compound 3 (2.50 g, 1.96 mmol) in dichloromethane (100 mL) and stirred at room temperature overnight. Subsequently, a saturated sodium carbonate solution was added to the reaction mixture to quench the excess acid. The mixture was then extracted with dichloromethane, washed with brine, and the organic phase was dried over anhydrous sodium sulfate. The solvent was then removed under vacuum to obtain a yellow solid product PADC. 1H NMR (400 MHz, CDCl3, ppm): δ = 10.03 (s, 4H), 8.25 (m, 4H), 7.92 (d, J = 8.3 Hz, 8H), 7.71 (d, J = 8.3 Hz, 8H), 7.56 (d, J = 8.8 Hz, 8H), 7.47 (m, 4H), 7.28 (d, J = 8.8 Hz, 8H).

[0043] Example 3

[0044] The organic covalent framework material prepared in Example 1 was used for the detection of aqueous nitrofuran antibiotics:

[0045] The covalent organic framework was used as a fluorescent sensor to detect antibiotics in aqueous solution: the solid product obtained by the activation (activation process: purification process (using at least one of tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, dimethyl sulfoxide to Soxhlet extraction of the solid product, and finally Soxhlet extraction of the solid with dichloromethane) was dried under vacuum at 100°C for 6 hours.) The covalent organic framework material was dispersed in ultrapure water and ultrasonicated for several minutes to keep the solid stably and evenly suspended in the aqueous solution. The antibiotic aqueous solution (1mM) was added dropwise to the covalent organic framework suspension (1mg / 3mL), 20μL was added each time, and the fluorescence intensity was recorded.

[0046] Figure 4 Figure 1 is the solid fluorescence and antibiotic detection results. Figure a is the solid fluorescence of the covalent organic framework prepared by the present invention, and Figure bd is the fluorescence detection result of nitrofuran antibiotics (nitrofuracil, furazolidone, furazolidone) in the aqueous phase. It can be seen from the figure that during the addition of antibiotics to the aqueous suspension of the covalent organic framework material, the fluorescence intensity of the system rapidly weakens, indicating that the covalent organic framework material has a fluorescence quenching response effect on antibiotics and can be used for the detection of nitrofuran antibiotics in the aqueous phase.

[0047] The above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principle of the present invention, and these improvements and changes are also regarded as the protection scope of the present invention.

Claims

1. A fluorescent covalent organic framework material that can be used for antibiotic detection, characterized in that: The molecular structure of the covalent organic framework material is The covalent organic framework material is a novel sql plane interlaced topological structure.

2. A method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection as claimed in claim 1, characterized in that: The aldehyde precursor and the amino precursor are dispersed in a solvent, and a catalyst is added. The obtained mixed system is reacted at 80-160° C. under vacuum or inert atmosphere. After the reaction is completed, a yellow solid powder is obtained, which is purified and dried to obtain the covalent organic framework.

3. The method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection according to claim 2, characterized in that: The amino precursor is The aldehyde precursor is 4. The method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection according to claim 2, characterized in that: The solvent is a good solvent, or a solution formed by mixing a good solvent and a poor solvent in any volume ratio: the good solvent is at least one of toluene, chloroform, o-dichlorobenzene, and mesitylene; the poor solvent is at least one of n-hexane, n-butanol, tert-butanol, and isopropanol.

5. The method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection according to claim 2, characterized in that: The catalyst is acetic acid.

6. The method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection according to claim 2, characterized in that: The molar ratio of the amino precursor, the aldehyde precursor and the catalyst is 1:1:30-150; the concentration of the amino precursor in the mixed system is 0.01-0.1 mol / L, and the concentration of the catalyst is 1-17 mol / L.

7. The method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection according to claim 2, characterized in that: The purification process is to use at least one of tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide and dimethyl sulfoxide to Soxhlet extract the solid product, and finally use dichloromethane to Soxhlet extract the solid.

8. The method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection according to claim 2, characterized in that: The preparation method of the precursor molecule is as follows: The preparation method of the aldehyde precursor or amino precursor is as follows: the halogenated molecule, phenylboronic acid reagent, catalyst and alkali agent are dispersed in a solvent, and then reacted at 80-120°C under an inert atmosphere. After the reaction is completed, the solvent is removed and purified to obtain a solid product, namely the aldehyde precursor or amino precursor.

9. The method for preparing a fluorescent covalent organic framework material that can be used for antibiotic detection according to claim 8, characterized in that: The halogenated molecules are N9, N9, N 10 ,N 10 -Tetrakis(4-bromophenyl)anthracene-9,10-diamine or N9,N9,N 10 ,N 10 -tetrakis(4-iodophenyl)anthracene-9,10-diamine, the phenylboronic acid reagent is at least one of 4-formaldehyde phenylboronic acid, 4-formaldehyde phenylboronic acid pinacol ester, 4-aminophenylboronic acid or 4-aminophenylboronic acid pinacol ester, the catalyst is tetrakistriphenylphosphine palladium, the alkali agent is at least one of cesium carbonate, potassium carbonate, sodium carbonate and potassium phosphate, the solvent is at least one of toluene, 1,4-dioxane and N,N-dimethylformamide, and the molar ratio of the halogenated molecule, the phenylboronic acid reagent, the tetrakistriphenylphosphine palladium and the alkali agent is 50:200-500:5:200-500.

10. A use of the fluorescent covalent organic framework material for antibiotic detection as claimed in claim 1 or the fluorescent covalent organic framework material for antibiotic detection prepared by the preparation method of any one of claims 2 to 9, characterized in that: The covalent organic framework is applied to the fluorescence detection of nitrofuran antibiotics in aqueous phase.

Images