Three-dimensional cadmium metal-organic framework material with fluorescence detection function and synthesis and application thereof

Abstract

The application discloses a three-dimensional cadmium metal organic framework material with a fluorescent detection function, and synthesis and application thereof, and has a chemical formula of Cd4(BTB)3(DMF)2(H2O)6·((CH3)2NH2). The synthesis method of the three-dimensional cadmium metal organic framework material is generated by a solvothermal reaction of 1,3,5 benzene-triphenylmethane acid BTB and anhydrous cadmium nitrate. The three-dimensional cadmium metal organic framework material with the fluorescent detection function is applied to detection of p-nitrophenol. The complex can specifically detect p-nitrophenol, has strong anti-interference ability, low detection limit and fast response speed, has strong acid and alkali resistance, and good fluorescent stability. In addition, the three-dimensional cadmium metal organic framework material has low raw material cost, simple and environment-friendly synthesis method, and high yield.

Description

Technical Field

[0001] This invention relates to the field of chemistry, specifically to a three-dimensional cadmium metal-organic framework material with fluorescence detection function, its synthesis, and its application. Background Technology

[0002] p-Nitrophenol, also known as 4-nitrophenol, is one of the most commonly used phenols globally. It is a highly toxic and persistent organic pollutant, listed as a priority pollutant by the U.S. Environmental Protection Agency. It is widely used in pharmaceutical, pesticide, and dye industries, originating from industrial wastewater, pesticide use, and dye application. PNP exhibits carcinogenic, teratogenic, and mutagenic effects, and can disrupt the endocrine system, damaging organs such as the hematopoietic, nervous, liver, and kidneys. Due to its high environmental persistence, it easily accumulates in water and soil and amplifies through the food chain, posing a serious threat to ecosystems and human health. Current detection methods for PNP include high-performance liquid chromatography (HPLC) and electrochemical methods. Designing a material capable of accurately and efficiently identifying p-nitrophenol is crucial for improving detection efficiency.

[0003] Current detection methods are mostly complex and time-consuming. In contrast, fluorescence-based methods offer lower detection limits, faster reaction rates, and simpler operation, making them a promising approach for detecting p-nitrophenol.

[0004] Metal-organic frameworks (MOFs) are novel porous crystalline materials formed by the self-assembly of metal ions / clusters and organic ligands through coordination bonds. Their highly designable crystal structures, large specific surface areas, tunable pore sizes, and surface chemistry provide an ideal platform for applications in cutting-edge fields such as gas storage and separation, heterogeneous catalysis, chemical sensing, drug delivery, and proton conduction. Particularly in the field of chemical sensing, especially in fluorescence detection, MOFs demonstrate immense application potential. Their extremely fast fluorescence response, designable fluorescent sites, and low detection limits offer unique advantages over other detection methods. Consequently, an increasing number of metal fluorescent probes are being designed for the detection of environmental pollutants and toxins, small molecule food products, and biotoxins. Currently, however, no fluorescent probes based on MOFs have been developed for the recognition of p-nitrophenol.

[0005] As a unique cadmium metal-organic framework material, its fluorescence properties mainly derive from ligand luminescence. A three-dimensional metal-organic framework with a double-interpenetrating structure is constructed through coordination between metallic cadmium and carboxyl groups in the ligands. Its fluorescence properties enable the specific detection of p-nitrophenol, exhibiting low detection limits, high sensitivity, and strong anti-interference capabilities. Summary of the Invention

[0006] The purpose of this invention is to address the problem that no fluorescent probe for p-nitrophenol based on metal-organic framework materials has been developed in the prior art, and to provide a three-dimensional cadmium metal-organic framework material with fluorescence detection function, as well as its synthesis and application.

[0007] To address the shortcomings of the aforementioned technical problems, the present invention employs the following technical solution: a three-dimensional cadmium metal-organic framework material with fluorescence detection function, the chemical formula of which is Cd4(BTB)3(DMF)2(H2O)6·((CH3)2NH2), wherein BTB is 1,3,5-benzene-tribenzoic acid; the three-dimensional cadmium metal-organic framework material is monoclinic, space group C2 / c, and the cell parameters are as follows: a=17.0597(5)Å, b=30.1766(11)Å, c=25.7281(14)Å, α=90°, β=103.887(4)°, γ=90°, V=12857.8(9)Å 3 .

[0008] A method for synthesizing a three-dimensional cadmium metal-organic framework material with fluorescence detection capability, comprising a solvothermal reaction of 1,3,5-benzenetribenzoic acid (BTB) and anhydrous cadmium nitrate, wherein the reaction route is as follows: .

[0009] The method for synthesizing a three-dimensional cadmium metal-organic framework material with fluorescence detection function includes the following steps: S1. First, dissolve lithium hydroxide in deionized water and cadmium nitrate in DMF. Then, mix the two solutions with the ligand BTB, add DMF again, and ensure that the solution is fully dissolved and mixed evenly to obtain a mixed solution. S2. After sealing the mixture obtained in S1, react it at room temperature to obtain a colorless blocky crystal product, which is a three-dimensional cadmium metal-organic framework material with fluorescent recognition function.

[0010] As a further optimization of the synthesis method of a three-dimensional cadmium metal-organic framework material with fluorescence detection function of the present invention, the molar ratio of cadmium nitrate to ligand BTB in step S1 is 1:1.

[0011] As a further optimization of the synthesis method of a three-dimensional cadmium metal-organic framework material with fluorescence detection function according to the present invention, the reaction time at room temperature in step S2 is 48-96 h.

[0012] The application of the three-dimensional cadmium metal-organic framework material with fluorescence detection function in the detection of p-nitrophenol.

[0013] The application of the three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions containing metal salt ions.

[0014] The application of the three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions containing other water pollutants.

[0015] In the application of the three-dimensional cadmium metal-organic framework material of the present invention in the fluorescence detection of p-nitrophenol in aqueous solutions containing other water pollutants, the other water pollutants are any one or more of furazolidone, p-nitrophenyl acetate, L-adrenaline, pentabromophenol, perfluorononanoic acid, tricresyl phosphate, and 6PPD.

[0016] The application of the three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions with pH 5-11.

[0017] Compared with the prior art, the present invention has the following beneficial effects: Firstly, the three-dimensional cadmium metal-organic framework material of this invention with fluorescence recognition can specifically detect p-nitrophenol and has strong anti-interference ability, with a low detection limit and a fast response speed.

[0018] Secondly, the three-dimensional cadmium metal-organic framework material with fluorescence recognition of the present invention has strong acid and alkali resistance and good fluorescence stability.

[0019] Thirdly, the raw materials used in the preparation of the three-dimensional cadmium metal-organic framework material with fluorescence recognition by this invention have low cost, the synthesis method is simple and environmentally friendly, and the yield is high. Attached Figure Description

[0020] Figure 1 This is a synthesis reaction route diagram for the three-dimensional cadmium metal-organic framework material with fluorescence detection function of the present invention; Figure 2 This invention discloses a three-dimensional cadmium metal-organic framework material with a double-interpenetrating structure as observed from the a-axis direction. Figure 3 a represents the coordination mode of a cadmium metal-organic framework material with fluorescence detection function and BTB ligand according to the present invention. Figure 3 b is a single-layer structure diagram of a cadmium metal-organic framework material with fluorescence detection function as observed from the a-axis direction according to the present invention; Figure 4 This is a powder X-ray diffraction pattern of the three-dimensional cadmium metal-organic framework material with fluorescence detection function of the present invention; Figure 5 a shows the fluorescence response of the three-dimensional cadmium metal-organic framework material with fluorescence detection function of this invention to different concentrations of p-nitrophenol in aqueous solution. Figure 5 b is a low-concentration fitting curve of p-nitrophenol in aqueous solution for the three-dimensional cadmium metal-organic framework material with fluorescence detection function of the present invention. Figure 5 c represents the fitted curve for high concentrations; Figure 6 This is a fluorescence response diagram of the three-dimensional cadmium metal-organic framework material with fluorescence detection function of the present invention to p-nitrophenol in various common metal salt solutions in water. Figure 7 The fluorescence response diagram of the three-dimensional cadmium metal-organic framework material with fluorescence detection function of the present invention for detecting nitrophenol in various common water pollutants; Figure 8 This is a schematic diagram showing the fluorescence intensity changes of the three-dimensional cadmium metal-organic framework material with fluorescence recognition function in aqueous solutions at different pH values ​​according to the present invention. Figure 9 The infrared spectrum of the three-dimensional cadmium metal-organic framework material complex with fluorescence detection function of the present invention and the ligand H3BTB. Figure 10 Thermogravimetric analysis curves of the three-dimensional cadmium metal-organic framework material complex with fluorescence detection function of this invention are shown. Detailed Implementation

[0021] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0022] A three-dimensional cadmium metal-organic framework material with fluorescence detection function has the chemical formula Cd4(BTB)3(DMF)2(H2O)6·((CH3)2NH2), where BTB is 1,3,5-benzene-tribenzoic acid; the three-dimensional cadmium metal-organic framework material is monoclinic, space group C2 / c, and the cell parameters are as follows: a=17.0597(5)Å, b=30.1766(11)Å, c=25.7281(14)Å, α=90°, β=103.887(4)°, γ=90°, V=12857.8(9)Å. 3 .

[0023] A method for synthesizing a three-dimensional cadmium metal-organic framework material with fluorescence detection capability, comprising a solvothermal reaction of 1,3,5-benzenetribenzoic acid (BTB) and anhydrous cadmium nitrate, wherein the reaction route is as follows: .

[0024] The synthesis method of the above-mentioned three-dimensional cadmium metal-organic framework material with fluorescence detection function includes the following steps: S1. First, dissolve lithium hydroxide in deionized water and cadmium nitrate in DMF. Then, mix the two solutions with the ligand BTB, add DMF again, and ensure that the solution is fully dissolved and mixed evenly to obtain a mixed solution. S2. After sealing the mixture obtained in S1, react it at room temperature for 48-96 hours to obtain a colorless blocky crystal product, which is a three-dimensional cadmium metal-organic framework material with fluorescent recognition function.

[0025] To improve the implementation effect of the synthesis method of the three-dimensional cadmium metal-organic framework material of the present invention, 4.2 mg of lithium hydroxide is dissolved in 1 ml of deionized water and 19.7 mg of cadmium nitrate is dissolved in 1 ml of DMF; and the molar ratio of cadmium nitrate to ligand BTB in step S1 is 1:1.

[0026] The application of the three-dimensional cadmium metal-organic framework material with fluorescence detection function in the detection of p-nitrophenol.

[0027] The application of the three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions containing metal salt ions.

[0028] The application of the three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions containing other water pollutants, wherein the other water pollutants are any one or more of furazolidone, p-nitrophenyl acetate, L-adrenaline, pentabromophenol, perfluorononanoic acid, tricresyl phosphate, and 6PPD.

[0029] The application of the three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions with pH 5-11.

[0030] The method for applying the three-dimensional cadmium metal-organic framework material with fluorescence detection function to the detection of p-nitrophenol described in this invention comprises the following steps: The three-dimensional cadmium metal-organic framework material was finely ground and then ultrasonically dispersed in a deionized aqueous solution to obtain a suspension. The suspension was transferred to a cuvette for fluorescence testing using a pipette. Then, a quantitative amount of p-nitrophenol was added and fluorescence testing was performed again. The identification and detection of p-nitrophenol was completed by observing the change in fluorescence intensity.

[0031] Furthermore, the fluorescence intensity of the measured cadmium metal-organic framework material was used as the initial fluorescence intensity. Subsequently, a quantitative amount of p-nitrophenol was continuously added to the cadmium metal-organic framework material suspension using a pipette, and the fluorescence intensity was measured after each addition of p-nitrophenol until the measured fluorescence intensity reached the quenching effect. The linear relationship and the lowest detection limit of the cadmium metal-organic framework material with fluorescence recognition function for detecting p-nitrophenol were obtained by linearly fitting different concentrations of p-nitrophenol with their corresponding fluorescence intensities.

[0032] Next, the three-dimensional cadmium metal-organic framework material of the present invention will be described in detail: This invention discloses a cadmium metal-organic framework material with fluorescent detection function, formed by cadmium nitrate and ligand 1,3,5-benzene-tribenzoic acid (BTB) through metal coordination. The three-dimensional structure of this cadmium metal-organic framework material is as follows: Figure 2 As shown in Table 1 below; the crystallographic parameters of the three-dimensional cadmium metal-organic framework material complex with fluorescence detection function of the present invention are shown in Table 1 below; the infrared spectra of the three-dimensional cadmium metal-organic framework material complex of the present invention and the ligand H3BTB are shown in Table 1 below. Figure 9 As shown; the thermogravimetric analysis curve of the three-dimensional cadmium metal-organic framework material complex with fluorescence detection function of the present invention is shown in the figure. Figure 10 As shown.

[0033] Table 1: Crystallographic parameters of the three-dimensional cadmium metal-organic framework material complexes of the present invention The structural formula of BTB is as follows: The aforementioned three-dimensional cadmium metal-organic framework material with fluorescence detection function is generated by a solvothermal reaction of 1,3,5-benzenetribenzoic acid (BTB) and cadmium nitrate, as shown in the reaction flowchart. Figure 1 As shown.

[0034] The structure and characterization of the three-dimensional cadmium metal-organic framework material with fluorescence detection function are described. Single-crystal X-ray diffraction analysis shows that the complex 1 of this invention crystallizes in the C2 / C space group, and the asymmetric unit contains three crystallographically independent Cd atoms. 2+ The Cd1 center coordinates with four oxygen atoms from two carboxylic acid groups from two different ligands, and simultaneously with oxygen atoms from two carboxylic acid groups from two other different ligands, with two of these oxygen atoms bridging to the Cd3 center. The Cd3 center also coordinates with two additional oxygen atoms from the carboxylic acid group, one oxygen atom from another ligand, and oxygen atoms from two coordinated water molecules, ultimately forming a [Cd2] binuclear cluster. The Cd2 center coordinates with four oxygen atoms from two carboxylic acid groups from two different ligands, oxygen atoms from two coordinated water molecules, and an oxygen atom from a coordinated DMF molecule. Each BTB ligand connects a [Cd2] cluster and a Cd1 ion, constructing a three-dimensional metal-organic framework with a double-interpenetrating structure, such as... Figure 3 a. When viewed along the a-axis, complex 1 exhibits hexagonal channels with dimensions of 14.60 × 10.40 Å, as shown in the image. Figure 3 b.

[0035] The PXRD images of the cadmium metal-organic framework material samples of the present invention fit very well with the PXRD images simulated from their corresponding single-crystal data (as shown in the appendix). Figure 4 As shown in the figure, this proves that its cadmium metal-organic framework material is a pure phase and has a complete structure.

[0036] The synthesis and application of the three-dimensional cadmium metal-organic framework material of the present invention will be further explained below with reference to specific embodiments. Example 1:

[0037] The method for synthesizing the three-dimensional cadmium metal-organic framework material with fluorescence recognition function according to the present invention includes the following steps: S1. Dissolve 4.2 mg of lithium hydroxide in 1 ml of deionized water, and dissolve 19.7 mg of cadmium nitrate in 1 ml of N,N,dimethylformamide (DMF). Then, mix the two solutions with 43.8 mg of ligand BTB, and add 1 ml of dimethylformamide (DMF) to the mixed solution to ensure it is fully dissolved and mixed evenly, thus obtaining a mixed solution.

[0038] S2. Transfer the mixture obtained in S1 to a 5mL glass vial, seal it, and react at room temperature for 72 hours to obtain a white blocky crystalline product, which is the cadmium metal-organic framework material with fluorescent recognition function.

[0039] The three-dimensional cadmium metal-organic framework material with fluorescence recognition function of the present invention can specifically detect p-nitrophenol.

[0040] The structural diagram of p-nitrophenol is as follows: I. Application of three-dimensional cadmium metal-organic framework materials in the detection of p-nitrophenol in deionized aqueous solutions The synthesized cadmium metal-organic framework material with fluorescence recognition and detection function was thoroughly ground, and an appropriate amount of powder was weighed and dispersed in deionized water. The mixture was then ultrasonically treated to form a homogeneous suspension. The fluorescence emission spectrum was subsequently measured, and the results showed that the maximum emission wavelength of the suspension was 270 nm. A certain amount of p-nitrophenol was added to the above system, and after each addition, the mixture was thoroughly mixed and the change in fluorescence intensity was measured.

[0041] A certain amount of p-nitrophenol was added each time using a pipette, changing the concentration of p-nitrophenol in the suspension. Its fluorescence intensity at 270 nm was measured. It was found that the fluorescence intensity gradually decreased as the concentration of p-nitrophenol increased until a fluorescence quenching effect was achieved (e.g., Figure 5 As shown in a). Quantitative analysis showed that its detection limit (based on...) The method was 0.60 × 10 -5 The concentration was mol / L, indicating good sensitivity. Linear fitting of the ratio of initial fluorescence intensity to real-time fluorescence intensity at 270 nm with the concentration of p-nitrophenol yielded I0 / I = 0.998 + 0.00754C in the low concentration region (e.g., mol / L). Figure 5 The relationship shown in b) is given. The quenching constant K svIt is 7.54×10 -3 L / µmol. The relationship between I0 and I conforms to the Stern-Volmer (SV) equation (where K sv Where is the quenching constant, C is the analyte concentration, I is the real-time fluorescence intensity after the addition of p-nitrophenol solution, and I0 is the initial fluorescence intensity without the addition of p-nitrophenol solution. The correlation coefficient R0 2 =0.999 (as attached) Figure 5 (as shown in c).

[0042] II. Application of the aforementioned three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions containing metal salt ions. The interference resistance of three-dimensional cadmium metal-organic framework materials was determined by adding aqueous solutions of common metal salt ions from water.

[0043] Five equal-volume suspensions of cadmium metal-organic framework material were prepared according to the above procedure, and their initial fluorescence emission spectra were measured. Subsequently, aqueous solutions of common metal salts (NaCl, Zn(CH3COO)2, CaCl2, and Na2SO4) with the quenching capacity of p-nitrophenol were added to four of the suspensions, respectively. The remaining suspension containing only p-nitrophenol served as a control. After thorough mixing, the fluorescence emission spectra of each system were measured, and the data were normalized. The results are shown in the attached figure. Figure 6 As shown in the figure, the material still maintains stable fluorescence recognition performance and exhibits strong anti-interference ability.

[0044] III. Application of the aforementioned three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions containing other water pollutants. The specific detection capability of three-dimensional cadmium metal-organic framework materials was determined by adding other analytes that are also water pollutants.

[0045] Eight equal-volume suspensions of cadmium metal-organic framework material were prepared according to the above procedure, and their initial fluorescence emission spectra were measured. Subsequently, equal amounts of potential interfering agents, including furacilin, p-nitrobenzene acetate, L-adrenaline, pentabromophenol, perfluorononanoic acid, tricresyl phosphate, and a 6PPD aqueous solution, were added to seven of the suspensions, with the remaining suspension serving as a blank control. After thorough mixing of all systems, their fluorescence emission spectra were measured, and the obtained data were normalized. The results (see attached) are... Figure 7 Only p-nitrophenol can cause significant fluorescence quenching, proving that the material has the ability to specifically detect p-nitrophenol.

[0046] IV. Application of the aforementioned three-dimensional cadmium metal-organic framework material in the fluorescence detection of p-nitrophenol in aqueous solutions with pH 5-11 The fluorescence stability of the three-dimensional cadmium metal-organic framework material was determined by adding a series of solutions with different pH values.

[0047] Seven equal-volume suspensions of cadmium-based metal-organic framework materials were prepared, and their initial fluorescence emission spectra were measured. Subsequently, aqueous solutions containing the quenching capacity of p-nitrophenol at pH values ​​of 5, 7, 8, 9, 10, and 11 were added to six of these suspensions, respectively, with the remaining suspension serving as a blank control. The fluorescence emission spectra of each group of samples were measured and normalized. The results are shown in the attached figure. Figure 8 This cadmium metal-organic framework material exhibits strong fluorescence stability over a wide pH range.

[0048] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A three-dimensional cadmium metal-organic framework material with fluorescence detection function, characterized in that: Its chemical formula is Cd4(BTB)3(DMF)2(H2O)6·((CH3)2NH2), where BTB is 1,3,5-benzene-tribenzoic acid; the three-dimensional cadmium metal-organic framework material is monoclinic, space group C2 / c, and its cell parameters are as follows: a=17.0597(5)Å, b=30.1766(11)Å, c=25.7281(14)Å, α=90°, β=103.887(4)°, γ=90°, V=12857.8(9)Å 3 .

2. The method for synthesizing a three-dimensional cadmium metal-organic framework material with fluorescence detection function as described in claim 1, characterized in that: It is produced by a solvothermal reaction of 1,3,5-benzenetribenzoic acid (BTB) and anhydrous cadmium nitrate, as shown in the following reaction route: .

3. The method for synthesizing a three-dimensional cadmium metal-organic framework material with fluorescence detection function as described in claim 2, characterized in that: Includes the following steps: S1. First, dissolve lithium hydroxide in deionized water and cadmium nitrate in DMF. Then, mix the two solutions with the ligand BTB, add DMF again, and ensure that the solution is fully dissolved and mixed evenly to obtain a mixed solution. S2. After sealing the mixture obtained in S1, react it at room temperature to obtain a colorless blocky crystal product, which is a three-dimensional cadmium metal-organic framework material with fluorescent recognition function.

4. The method for synthesizing a three-dimensional cadmium metal-organic framework material with fluorescence detection function as described in claim 3, characterized in that: In step S1, the molar ratio of cadmium nitrate to ligand BTB is 1:

1.

5. The method for synthesizing a three-dimensional cadmium metal-organic framework material with fluorescence detection function as described in claim 3, characterized in that: The reaction time at room temperature in step S2 is 48-96 hours.

6. The application of the three-dimensional cadmium metal-organic framework material with fluorescence detection function as described in claim 1 in the detection of p-nitrophenol.

7. The application of the three-dimensional cadmium metal-organic framework material as described in claim 1 in the fluorescence detection of p-nitrophenol in aqueous solutions containing metal salt ions.

8. The application of the three-dimensional cadmium metal-organic framework material as described in claim 1 in the fluorescence detection of p-nitrophenol in aqueous solutions containing other water pollutants.

9. The application of the three-dimensional cadmium metal-organic framework material as described in claim 8 in the fluorescence detection of p-nitrophenol in aqueous solutions containing other water pollutants, characterized in that: The other water pollutants mentioned are any one or more of furazolidone, p-nitrophenyl acetate, L-adrenaline, pentabromophenol, perfluorononanoic acid, tricresyl phosphate, and 6PPD.

10. The application of the three-dimensional cadmium metal-organic framework material as described in claim 1 in the fluorescence detection of p-nitrophenol in aqueous solutions with pH 5-11.

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