A metal organic framework compound, a preparation method and application in environmental pollutant detection

Abstract

The application discloses a metal organic framework compound, a preparation method and application in environmental pollutant detection, and can be used for detecting environmental pollutants such as baicalin, Fe 3+ , CrO4 2‑ , etc. in water. The novel metal organic framework compound material synthesized by the application has excellent luminescence performance, can not only recognize heavy metal ions Fe 3+ from numerous metal ions, but also can recognize the strong polluting anion CrO4 2‑ , and can also recognize baicalin molecules from various antibacterial drug molecules in water. The detection limit of the material to different ions and molecules is low, and the material has the advantages of convenient preparation, low cost, simple operation, high sensitivity and high selectivity.

Description

Technical Field

[0001] This invention belongs to the field of metal-organic framework material application technology, and provides a metal-organic framework compound, a preparation method, and its application in the detection of environmental pollutants. Background Technology

[0002] With industrial development, the number of potential pollution sources in water bodies is increasing. Besides heavy metal pollution, which is already well-known to applicants, new pollutants have become a key focus of environmental monitoring due to their wide range of sources, severe hazards, hidden risks, environmental persistence, and complex remediation. Antimicrobial drugs are one such new pollutant. In water bodies, antimicrobial drugs not only adversely affect aquatic ecosystems but also harm human health through various pathways. Baicalin, a flavonoid compound, has antibacterial, diuretic, anti-inflammatory, and cholesterol-lowering effects and is a common antimicrobial drug.

[0003] Metal-organic frameworks (MOFs) are organic-inorganic hybrid crystalline materials rich in active sites and with tunable structures. They possess advantages such as structural diversity, variable properties, and mild and operable synthesis conditions. Furthermore, due to the controllable and tunable nature of their organic ligands, MOFs exhibit advantages over traditional optical materials in fluorescence sensing and show promising application prospects in antibacterial drugs and heavy metal ion detection.

[0004] With the increasing prevalence of pollutants, more and more detection methods and probes are being developed. Fluorescence sensing, due to its advantages such as simple operation and high sensitivity, is widely used in the detection of environmental pollutants.

[0005] Patent application CN118425112A discloses the application of boric acid-functionalized lanthanide metal-organic framework BA-Eu-MOF in the detection of flavonoid glycosides. BA-Eu-MOF has highly uniform nanoscale cavities and a large specific surface area, which allows six flavonoid glycosides to be efficiently enriched in the pores, thus having a low detection limit and high sensitivity. It can simultaneously detect six flavonoid glycosides, namely baicalin, quercetin, wogonin, astragalin, puerarin, and rutin, and has a rapid response.

[0006] Patent application CN108165262A discloses a luminescent metal-organic framework material for metal ion detection and its preparation method. This material is effective for Fe... 3+ It has specific identification and detection functions.

[0007] Patent CN111793493B discloses a cationic metal-organic framework material based on amphoteric ligands for highly selective detection of chromate. The ligand H2L·2Cl and magnesium nitrate are added to a mixture of methanol and acetonitrile. After mixing evenly, the mixture is heated in a reaction vessel for a period of time to obtain colorless prismatic transparent crystals. After washing, filtering, and drying, the cationic metal-organic framework material based on amphoteric ligands for highly selective detection of chromate is obtained.

[0008] The above patented technologies can only be used to detect one of scutellarin, iron ions or chromate. However, with the increase of pollutants, there are very few fluorescent probes that can detect antibacterial drugs and heavy metal pollutants at the same time, which cannot meet the complex and diverse needs of environmental pollutant detection. Summary of the Invention

[0009] In view of this, the purpose of the present invention is to provide a metal-organic framework compound, a preparation method thereof, and its application in the detection of environmental pollutants.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] 1. A metal-organic framework compound having the chemical formula [Cd(H₂L)(bib)]n, wherein H₂L is 3,5-bis(3'-carboxyphenoxy)-1,2,4-triazole, bib is 1,4-bis(1-imidazolyl)benzene, and n is an integer greater than 1; the single-crystal structure of the compound belongs to the triclinic crystal system, space group P-1, and the cell parameters are: bond length bond length bond length Bond angle α = 93.211(12)°, bond angle β = 91.972(11)°, bond angle γ = 111.877(10)°.

[0012] As one of the preferred technical solutions, the molecular formula of the compound is C1. 28 H 19 CdN7O4.

[0013] As one of the preferred technical solutions, the molecular weight of the compound is 629.90.

[0014] As one of the preferred technical solutions, the single crystal structure has a unit cell volume. Number of molecules in unit cell Z = 4, crystal density ρ calcd =1.672g / cm 3 The linear absorption coefficient μ = 0.924 mm –1 Number of electrons in unit cell F(000) = 1264, diffraction angle range θRange = 1.0-25.0 degrees, diffraction point collection = 8732, independent diffraction points (R int=0.000, the number of diffractions with an intensity greater than 2σ = 5582.

[0015] 2. The aforementioned method for preparing a metal-organic framework compound involves mixing H2L, bib, Cd(ClO4)2·6H2O, and water and stirring for 15–45 minutes. The mixture is then transferred and sealed in a reactor, heated to 110–140°C, kept at that temperature for 68–80 hours, and cooled to room temperature to obtain the compound. The molar ratio of H2L, bib, and Cd(ClO4)2·6H2O is 2:2:2.7–3.6, the volume ratio of H2L to water is 0.1 mmol:9–15 mL, H2L is 3,5-bis(3'-carboxyphenoxy)-1,2,4-triazole, and bib is 1,4-bis(1-imidazolyl)benzene.

[0016] As one of the preferred technical solutions, H2L, bib, Cd(ClO4)2·6H2O and water are mixed and stirred for 30 minutes, then transferred and sealed in a reactor, heated to 120℃, kept at that temperature for 72 hours, and cooled to room temperature to obtain the product; wherein, the molar ratio of H2L, bib and Cd(ClO4)2·6H2O is 2:2:3, and the volume ratio of H2L to water is 0.1mmol:10mL.

[0017] As one of the preferred technical solutions, the heating rate is 7-13℃ / h and the cooling rate is 3-8℃ / h.

[0018] As one of the further preferred technical solutions, the heating rate is 8℃ / h and the cooling rate is 5℃ / h.

[0019] 3. The application of the aforementioned metal-organic framework compound in the detection of environmental pollutants.

[0020] As one of the preferred technical solutions, the environmental pollutants include: antibacterial drugs, cationic pollutants, and anionic pollutants.

[0021] As one of the preferred technical solutions, the environmental pollutants include: scutellarin, Fe... 3+ CrO4 2- .

[0022] The beneficial effects of this invention are:

[0023] This invention synthesizes a novel metal-organic framework compound that can be used for the synthesis of scutellarin and Fe in water. 3+ CrO4 2- The novel metal-organic framework compound material synthesized in this invention exhibits excellent luminescent properties, enabling the identification of heavy metal ions such as Fe from a wide range of metal ions. 3+ It can also identify the highly polluting anion CrO4. 2-Furthermore, it can identify baicalin molecules among various biomolecules in water. The material exhibits low detection limits for different ions and molecules, demonstrating its advantages of convenient preparation, low cost, simple operation, high sensitivity, and high selectivity.

[0024] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0026] Figure 1 The chemical structural formula of the ligand of the metal-organic framework compound (sample 1) of the present invention is shown below.

[0027] Figure 2 Infrared (A) and thermogravimetric (B) analyses of sample 1 of the present invention;

[0028] Figure 3 The X-ray diffraction pattern is for a single crystal.

[0029] Figure 4 The crystal structure is a single crystal, where A is the coordination environment diagram of sample 1, B is the 1D chain formed along the A-axis, C is the 1D chain formed along the C-axis, and D is the 3D supramolecular structure formed by the 1D chain.

[0030] Figure 5 The UV absorption spectra of the main ligand, auxiliary ligand, sample 1, and different molecules are shown.

[0031] Figure 6 The fluorescence comparison images are of sample 1 and different ligands;

[0032] Figure 7 The graph shows the antimicrobial drug detection results for sample 1, where A is a curve graph and B is a bar graph.

[0033] Figure 8 The antimicrobial drug concentration was identified for sample 1 by titration, where A is the fitting graph and B is the curve graph;

[0034] Figure 9 This is an anti-interference bar chart of sample 1 for antimicrobial drug detection;

[0035] Figure 10 This is a comparison graph of fluorescence cycling data of sample 1 against antibacterial drugs;

[0036] Figure 11 For screening cations, A is a curve graph and B is a bar graph;

[0037] Figure 12 To identify cation concentration titrations, where A is a fitted graph and B is a curve graph;

[0038] Figure 13 This is a bar chart showing the resistance to interference from cations;

[0039] Figure 14 A comparison graph of fluorescence cycling data for cations;

[0040] Figure 15 For screening anions, A is a curve graph and B is a bar graph;

[0041] Figure 16 To identify anion concentration titration, A is the fitting graph and B is the curve graph;

[0042] Figure 17 This is a bar chart showing the resistance to interference from anions;

[0043] Figure 18 This is a comparison graph of fluorescence cycling data for anions;

[0044] Figure 19 For XRD comparison before and after titration. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments.

[0046] Example:

[0047] A metal-organic framework compound with the molecular formula C 28 H 19 CdN7O4, with the chemical formula [Cd(L)(bib)]n, wherein H2L is 3,5-bis(3'-carboxyphenoxy)-1,2,4-triazole, and bib is 1,4-bis(1-imidazolyl)benzene. Their chemical structural formulas are shown below. Figure 1 .

[0048] Synthesis method:

[0049] A mixture of H₂L (0.1 mmol, 0.03 g), bib (0.1 mmol, 0.021 g), Cd(ClO₄)₂·6H₂O (0.15 mmol, 0.06291 g), and 10 mL of H₂O was stirred for 30 minutes, then transferred and sealed in a 25 mL Teflon-lined reactor. The mixture was heated to 120 °C and held at this temperature for 72 hours, then cooled to room temperature at a rate of 5 °C / h. Pale white crystals, calculated as cadmium, were obtained, designated as Sample 1, with a yield of 62%. H₂L = 3,5-bis(3'-carboxyphenoxy)-1,2,4-triazole; bib = 1,4-bis(1-imidazolyl)benzene.

[0050] Characterization data:

[0051] The elemental analysis results are shown in Table 1; the crystal data are shown in Table 2; the selected bond lengths and bond angles are shown in Table 3; and the selected hydrogen bond distances and angles are shown in Table 4.

[0052] Table 1. Elemental Analysis Results

[0053]

[0054] Table 2. Crystal Data

[0055]

[0056]

[0057] *R=∑(F o –F c ) / ∑(F o ),**wR2={∑[w(F O(2) –F c 2 ) 2 ] / ∑(F O(2) ) 2} 1 / 2 .

[0058] Table 3. Selected bond lengths and bond angles

[0059]

[0060] Symmetry Codes:For1: #1=-1+x,-1+y,z; #2=-1-x,-1-y,-z; #3=-x,-y,-z; #4=-1+x,-1+y,z; #5=1-x,-y,1-zz.

[0061] Table 4 shows the selected hydrogen bond distances and bond angles.

[0062]

[0063]

[0064] Crystal structure analysis:

[0065] X-ray single-crystal structure analysis revealed that Sample 1 is composed of a triclinic P-1 space group and exhibits a one-dimensional chain structure. Combined with material analysis of the central ion coordination environment, Sample 1 was found to possess good symmetry and stability. Based on the coordination environment diagram of Sample 1 (…),… Figure 1 As shown in the figure, the asymmetric coordination environment unit contains one Cd. 2+ One oxygen-containing L 2- A ligand anion and a bib ligand molecule. One Cd in sample 1. 2+ Using two different Cd 2+ Composition, each Cd 2+ Each accounts for 50%. Cd39 and L from three different carboxylic acids. 2- The three oxygen atoms O12, O13, and O25 of the ligands, along with the two different bib ligands N34 and N55, form a five-coordinate trigonal bipyramidal spatial geometry, with O25 and N34 located at the vertices and the remaining atoms occupying the equatorial positions of the structure. Cd79 forms a bipyramidal structure with two different bib ligands. 2- The four oxygen atoms (O58, O72, O60 and O82) in one carboxyl group of the ligand are coordinated and connected with the two nitrogen atoms (N11 and N33) in the two coordinating bib groups to form a twisted octahedral geometry, in which O58 and N11 are located at the vertices of the octahedron, and the remaining atoms occupy the equatorial position of the structure.

[0066] Metal Cd 2+ With L 2- Oxycarboxylic acid coordinate anions adopt chelation and bidentate bridging coordination (coordination mode μ3-η). 1 :η 1 :η 1 and μ2-η 2 :η 2 The bib ligand adopts a bidentate bridging coordination mode (μ2-η). 1 :η 1 The Cd-O bonds in the structure have advantages in... Inside, the Cd-N bond length is located in The bond angles of O-Cd-O are in the range of 54.4(5) to 153.4(6)°, and the bond angles of O-Cd-N are in the range of 87.0(5) to 166.7(4)°. In the structure of sample 1, due to Cd... 2+ Center and L 2-The oxygen-containing ligand anion has two different coordination sites, which are then linked by bib-assisted ligands to form two different 1D chain structures. The 1D chain structures are then linked by hydrogen bonds such as NH…O, CH…O, and CH…N to form a 3D network structure.

[0067] Figure 2 In the image, A and B represent the infrared and thermogravimetric analyses of the single crystal, respectively. Figure 3 This is the X-ray diffraction pattern of a single-crystal powder. Figure 4 It has a single-crystal crystal structure.

[0068] See Figure 2 In sample B, the first step of weight loss occurs within the temperature range of 100-300℃, which is due to the loss of free water molecules in the sample. When the temperature rises above 337℃, the organic ligands L and bib in the sample begin to decompose slowly. When the temperature rises to 391℃, the backbone of the organic ligand molecules in the sample begins to collapse until the sample finally decomposes into oxides.

[0069] See Figure 3 The results show that within the range of 5-50 (2θ), the theoretical data plot and the experimentally measured plot of the sample show consistent peak shapes and 2θ positions in XRD, indicating that the sample is a pure phase. The main characteristic peaks are 7.48, 9.03, 11.32, 12.12, 14.06, 18.12, 20.41, 23.04, and 26.07.

[0070] Test case

[0071] 1. Antimicrobial drug identification:

[0072] The presence of a quenching agent (S1) against the antibacterial drugs thiamphenicol (THI), furazolidone (FZD), indomethacin (IMC), ciprofloxacin (CIP), pefloxacin (PMD), enrofloxacin (EFA), fleroxacin (FOA), amoxicillin (AMXL), and baicalin (BCL) was observed in experiments. For the sensing experiments, a dispersion of S1 (1 mg·mL⁻¹) was prepared by suspending 5 mg of S1 powder in 5 mL of water and then ultrasonically stirring the mixture for 30 minutes before testing. Titration experiments were conducted by gradually adding the aqueous solution of the antibacterial drug to the aqueous dispersion of S1. All experiments were repeated for four cycles. The quenching efficiency was calculated as [(I₀-I) / I₀]×100%, where I₀ and I are the fluorescence intensities before and after the addition of the analyte. These competitive experiments were conducted by adding 3 mL of BCL aqueous solution (1×10⁻¹) to the aqueous dispersion of S1. -3 M) added to 2 mL of molecular aqueous solution (1×10) -3 It was carried out in M).

[0073] 2. Cation recognition:

[0074] Sample 1 was found to have a positive effect on the cation Fe. 3+ It possesses sensing properties. Cation experiments include: magnesium ions (Mg... 2+ ), lead ions (Pb) 2+ ), zinc ions (Zn) 2+ Nickel ions (Ni) 2+ ), potassium ions (K) + Sodium ions (Na) + ), cadmium ions (Cd) 2 + ), iron ions (Fe) 3+ For the sensing experiments, a dispersion of Sample 1 (1 mg·mL⁻¹) was prepared by suspending the powder of Sample 1 (5 mg) in 5 mL of water and then ultrasonically stirring the mixture for 30 minutes before testing. Titration experiments were performed by gradually adding an aqueous cation solution to the aqueous dispersion of Sample 1. All experiments were repeated for four cycles. The quenching efficiency was calculated as [(I₀-I) / I₀]×100%, where I₀ and I are the fluorescence intensities before and after the addition of the analyte. These competitive experiments were conducted by adding 3 mL of Fe... 3+ Aqueous solution (1×10) -3 M) added to 2 mL of molecular aqueous solution (1×10) -3 It was carried out in M).

[0075] 3. Anion recognition:

[0076] Sample 1 and acetate ions (CH3COO) - ), sulfate ions (SO4) 2- ), sulfite ions (SO3) 2- ), nitrite ions (NO 2- ), nitrate ions (NO) 3- ), chlorate ions (ClO) 3- ), chromate ions (CrO4) 2- ), fluoride ions (F) - ), carbonate ions (CO3) 2- In experiments, it was found that it has a strong effect on chromate ions (CrO4). 2- It possesses sensing properties. In the sensing experiment, sample 1 (1 mg / mL) was prepared by suspending 5 mL of powder in 5 mL of water, and then ultrasonically stirring the mixture for 30 minutes before testing. -1 The titration was performed by gradually adding an aqueous solution of the anion to the aqueous dispersion of sample 1. All experiments were repeated for four cycles. The quenching efficiency was calculated as [(I0-I) / I0]×100%, where I0 and I are the fluorescence intensities before and after the addition of the analyte. These competitive experiments were performed by adding 3 mL of CrO4 to the aqueous dispersion of sample 1.2- Aqueous solution (1×10) -3 M) added to 2 mL of molecular aqueous solution (1×10) -3 It was carried out in M).

[0077] The results of the aforementioned experiments are as follows (Table 5):

[0078] 1. Antibacterial drug experiment:

[0079] Titration (using water as solvent): 0.001 mol / L DTZ

[0080] σ is 0.046823, Ksv = 106319.92

[0081] LOD is (3*0.046823) / 106319.92=1.32×10 -6 mol / L

[0082] 2. Cation experiment:

[0083] Titration (using water as solvent): 0.0005 mol / L Fe 3+

[0084] σ is 0.046823, Ksv = 13228.33

[0085] LOD is (3*0.046823) / 13228.33 = 1.06×10 -5 mol / L

[0086] 3. Anion experiment:

[0087] Titration (using water as solvent): 0.01 mol / L CrO4 2-

[0088] σ is 0.046823, Ksv = 2918.54

[0089] LOD is (3*0.046823) / 2918.54 = 4.81×10 -5 mol / L

[0090] Table 5. Identification of antimicrobial agents, cations, and anions in Sample 1

[0091] Titration (σ=0.03124) Ksv <![CDATA[R 2 ]]> LOD / (mol / L) 0.001 mol / L BCL 106319.92 0.97888 <![CDATA[1.32×10 -6 ]]> <![CDATA[0.0005mol / L Fe 3+ ]]> 13228.33 0.97246 <![CDATA[1.06×10 -5 ]]> <![CDATA[0.01mol / L CrO4 2- ]]> 2918.54 0.98922 <![CDATA[4.81×10 -5 ]]>

[0092] The applicant further identified antimicrobial drugs, cations, and anions in sample 1 of different water qualities, and the results are shown in Tables 6-8.

[0093] Table 6. Recognition performance of sample 1 against antimicrobial agents in different water qualities

[0094]

[0095] Table 7. Recognition performance of sample 1 for cations in different water qualities

[0096]

[0097] Table 8. Recognition performance of sample 1 for anions in different water qualities

[0098]

[0099] Figure 5 The UV absorption spectra of ligand compounds and antibacterial drugs show that the UV absorption peaks are mainly concentrated in the 200-300 nm range, with H2L having an absorption peak around 315 nm.

[0100] from Figure 6 The fluorescence comparison diagram shows that the fluorescence peaks of sample 1 and ligand bib are basically the same, with a small bulge between 320nm and 410-470nm. Compared with bib, the fluorescence peak of sample 1 is slightly red-shifted. The fluorescence pattern of ligand H2L is quite different from that of bib and single crystal 1, with its emission peak mainly in the range of 350-470nm.

[0101] See Figure 7 The fluorescence screening diagram of sample 1 for antibacterial drugs shows that the fluorescence intensity of CIP is significantly enhanced, while the fluorescence intensity of FZD, EFA, and FOA is significantly weakened, and BCL is quenched. This indicates that sample 1 can be used as a potential fluorescent probe for selective recognition of BCL.

[0102] See Figure 8 The quenching effect of BCL on the sample was studied by concentration titration experiments. The results showed that the luminescence intensity increased with the increase of BCL concentration, but the fluorescence intensity gradually decreased.

[0103] The relationship between the percentage of fluorescence quenching and the concentration of BCL in the sample fluorescence concentration titration was handled using the Stern-Volmer equation, see [link to relevant documentation]. Figure 8 In equation A, using the linear formula I0 / I = 1 + K... sv [Q], where K sv The constant represents the fluorescence quenching constant of the sample, Q represents different sample quenching concentrations, I0 represents the fluorescence intensity of the blank sample, and I represents the fluorescence intensity of the sample at a certain concentration. The quenching of sample fluorescence intensity is related to the concentration of BCL (from 0 to 8.26 × 10⁻⁶). -5 The fluorescence quenching constant (K mol / L) is an ideal linear relationship. Calculations using the Stern-Volmer linear equation show that the fluorescence quenching constant (K mol / L) is... svThe limit of fluorescence detection (LOD) was 1.32 × 10⁻⁶, which was 106319.92. -6 mol / L. Therefore, sample 1 can be used to detect BCL molecules.

[0104] Comparing the effects of different antibacterial drugs in the presence of... Figure 9 It can be seen that, under different antibacterial drugs or combinations of antibacterial drugs, the recognition of BCL by Sample 1 is not affected by other antibacterial drugs. Its anti-interference fluorescence cycling data... Figure 10 The results showed that sample 1 had no adsorption effect on antibacterial drugs and had good recyclability.

[0105] Screening test for cations in sample 1 Figure 11 It can be seen that the common cation Mg 2+ Pb 2+ Zn 2+ Ni 2+ K + Na + Cd 2+ All showed an increase in fluorescence intensity, with Pb showing the most significant increase. 2+ Zn 2+ K + Fluorescence enhancement was highest, while iron ions (Fe) showed the highest fluorescence enhancement. 3+ A very significant decrease in fluorescence intensity occurred.

[0106] In the concentration titration experiment for identifying cations ( Figure 12 It can be seen that, with Fe 3+ Concentration (in the range of 0-4.13*10) - 5 As the concentration increases within the range of mol / L, the fluorescence intensity gradually weakens, and the quenching of its intensity is related to Fe. 3+ The concentration exhibits a strong linear relationship, with a quenching constant of 13228.33 and a LOD of 1.06 × 10⁻⁶. -5 mol / L.

[0107] Anti-interference experiment against cations Figure 13 It can be seen that other common cations do not interfere with the pair of Fe in sample 1. 3+ The detection, and the cyclic test Figure 14 It can be seen that Sample 1 has a certain degree of recyclability. Starting from the third cycle, its performance decreases slightly, but the impact is not significant.

[0108] Sample 1 for anion screening Figure 15 It can be seen that the common anion CH3COO - SO4 2- SO3 2- NO 2- NO3- ,ClO 3- F - CO3 2- The fluorescence intensity of all of them increased, including ClO. 3- and CO3 2- The enhancement is most obvious, while CrO4 2- However, significant fluorescence quenching occurred, therefore sample 1 can serve as a potential fluorescent probe for detecting CrO4. 2- .

[0109] Identifying and fitting concentration titration plots of anions Figure 16 As can be seen, the fluorescence intensity of sample 1 decreases significantly with increasing anion concentration, and the intensity change shows a good linear relationship with concentration. Through fitting, the quenching constant is found to be 2918.54, and the LOD is 4.81 × 10⁻⁶. -5 mol / L.

[0110] The anion interference diagram clearly demonstrates that it is not affected by other anions or their combinations. Figure 17 It can be reused, but its performance changes slightly after N=3. Figure 18 ).

[0111] Different water qualities present different interfering factors. The applicant compared the effects of sample 1 on BCL and Fe in deionized water and different actual water bodies (such as tap water and Fuxi River water). 3+ CrO4 2- The detection effect was compared with the theoretical value, and it was found that the effect of BCL detection was less affected by the water body, but had a greater impact on the detection of cations and anions.

[0112] Titration of BCL and Fe 3+ CrO4 2- After the experiment, XRD analysis was performed on sample 1, and the peak values ​​were found to be consistent with the theoretical peak values ​​of sample 1, indicating that sample 1 did not adsorb the analyte during the titration process, nor did it undergo any structural changes. Figure 19 )

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A metal-organic framework compound, characterized in that, The chemical formula of this compound is [Cd(H2L)(bib)]n, where H2L is 3,5-bis(3'-carboxyphenoxy)-1,2,4-triazole and bib is 1,4-bis(1-imidazolyl)benzene; the single-crystal structure of this compound belongs to the triclinic crystal system, space group P-1, and the unit cell parameters are: bond length bond length bond length Bond angle α = 93.211(12)°, bond angle β = 91.972(11)°, bond angle γ = 111.877(10)°.

2. The metal-organic framework compound according to claim 1, characterized in that, The molecular formula of the compound is C 28 H 19 CdN7O4.

3. A metal-organic framework compound according to claim 1, characterized in that, The molecular weight of the compound is 629.

90.

4. A metal-organic framework compound according to claim 1, characterized in that, The single-crystal structure described above has a unit cell volume of Number of molecules in unit cell Z = 4, crystal density ρ calcd =1.672g / cm 3 The linear absorption coefficient μ = 0.924 mm –1 Number of electrons in unit cell F(000) = 1264, diffraction angle range θRange = 1.0-25.0 degrees, diffraction point collection = 8732, independent diffraction points (R int =0.000, the number of diffractions with an intensity greater than 2σ = 5582.

5. A method for preparing a metal-organic framework compound according to any one of claims 1 to 4, characterized in that, Mix H2L, bib, Cd(ClO4)2·6H2O and water and stir for 15–45 minutes. Then transfer and seal the mixture in a reactor, heat to 110–140°C, keep at that temperature for 68–80 hours, and cool to room temperature to obtain the final product. The molar ratio of H2L, bib, and Cd(ClO4)2·6H2O is 2:2:2.7–3.6, the volume ratio of H2L to water is 0.1 mmol:9–15 mL, H2L is 3,5-bis(3'-carboxyphenoxy)-1,2,4-triazole, and bib is 1,4-bis(1-imidazolyl)benzene.

6. The preparation method according to claim 5, characterized in that, The heating rate is 7–13℃ / h, and the cooling rate is 3–8℃ / h.

7. The application of a metal-organic framework compound according to any one of claims 1 to 4 in the detection of environmental pollutants.

8. The application according to claim 7, characterized in that, The environmental pollutants include: antimicrobial drugs, cationic pollutants, and anionic pollutants.

9. The application according to claim 7, characterized in that, The environmental pollutants include: scutellarin, Fe... 3+ CrO4 2- .

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