Metal organic framework compound, preparation method and application in environmental pollutant detection

Abstract

The invention discloses a metal organic framework compound, a preparation method and application in environmental pollutant detection. The metal organic framework compound can be used for detecting environmental pollutants such as baicalin, Fe < 3 + > and CrO4 < 2-> in water. The novel metal organic framework compound material synthesized by the invention has excellent luminescence property, not only can identify heavy metal ion Fe < 3 + > in numerous metal ions, but also can identify anion CrO4 < 2-> with strong pollution property, and meanwhile, can identify baicalin molecules in various antibacterial drug molecules in water. The material has low detection limit on different ions and molecules, and has the advantages of convenience in preparation, low cost, simplicity in operation, high sensitivity and high selectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of metal organic framework material application, and provides a metal organic framework compound, a preparation method and application in environmental pollutant detection. Background Art

[0002] With the development of industry, there are more and more potential sources of pollution in water bodies. In addition to the heavy metal pollution that the applicant is familiar with, new pollutants have become the focus of environmental detection due to their wide sources, serious hazards, hidden risks, environmental persistence and complexity of governance. Antimicrobial drugs are one of the new pollutants. Antimicrobial drugs in water bodies not only have adverse effects on aquatic ecosystems, but also cause harm to human health through various channels. Baicalin is a flavonoid compound that has antibacterial, diuretic, anti-inflammatory, cholesterol-lowering and other effects. It is a common antimicrobial drug.

[0003] Metal-organic framework materials are organic-inorganic hybrid crystal materials with rich active sites and adjustable structures. They have the advantages of structural diversity, performance variability, mild synthesis conditions and operability. In addition, due to the controllable and adjustable nature of organic ligands, metal-organic framework materials have advantages over traditional optical materials in fluorescence sensing and have shown good application prospects in the detection of antibacterial drugs and heavy metal ions.

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

[0005] Patent application CN118425112A discloses the application of a 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, so that six flavonoid glycosides can be efficiently enriched in the pores, thereby having a lower detection limit and higher sensitivity. It can also simultaneously detect six flavonoid glycosides, namely, baicalin, quercetin, baicalin, astragalus glycoside, puerarin and rutin, with a rapid response.

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

[0007] Patent CN111793493B discloses a cationic metal-organic framework material based on amphiphilic ligands for highly selective detection of chromate. 2L·2Cl and magnesium nitrate are added to a mixed solution consisting of methanol and acetonitrile, mixed evenly, and then heated in a reaction kettle for a period of time to obtain colorless prismatic transparent crystals, which are washed, filtered, and dried to obtain a cationic metal-organic framework material based on amphiphilic ligands for highly selective detection of chromate.

[0008] The above patented technology can only be used for the detection of one of baicalin, iron ions or chromate. However, with the increase of pollutants, there are very few fluorescent probes that can simultaneously detect antimicrobial drugs and heavy metal pollutants, which cannot meet the complex and diverse environmental pollutant detection needs. Summary of the invention

[0009] In view of this, the object of the present invention is to provide a metal organic framework compound, a preparation method and application in environmental pollutant detection.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] 1. A metal organic framework compound, the chemical formula of which is [Cd(H 2 L)(bib)]n, where H 2 L 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 system, the space group is P-1, and the unit cell parameters are: bond length Key length Key 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 C 28 H 19 CdN 7 O 4 .

[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, the unit cell volume The number of molecules in the unit cell is Z = 4, and the crystal density is ρ calcd =1.672g / cm 3 , linear absorption coefficient μ=0.924mm –1 , the number of electrons in the unit cell F(000) = 1264, the unit cell diffraction angle range θRange = 1.0-25.0deg, the diffraction point collection = 8732, the independent diffraction point (R int)=0.000, the number of diffractions with intensity greater than 2σ=5582.

[0015] 2. The method for preparing the aforementioned metal organic framework compound comprises: 2 L, bib, Cd(ClO 4 ) 2 6H 2 O and water are mixed and stirred for 15 to 45 minutes, then transferred and sealed in a reactor, heated to 110 to 140°C, kept warm for 68 to 80 hours, and cooled to room temperature to obtain; wherein, H 2 L, bib, Cd(ClO 4 ) 2 6H 2 The molar ratio of O is 2:2:2.7-3.6, H 2 The dosage ratio of L and water is 0.1mmol:9~15mL, H 2 L 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, H 2 L, bib, Cd(ClO 4 ) 2 6H 2 O and water were mixed and stirred for 30 minutes, then transferred and sealed in a reactor, heated to 120°C, kept warm for 72 hours, and cooled to room temperature to obtain the product; wherein, H 2 L, bib, Cd(ClO 4 ) 2 6H 2 The molar ratio of O is 2:2:3, H 2 The usage ratio of L and water is 0.1mmol:10mL.

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

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

[0019] 3. 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: antimicrobial drugs, cationic pollutants, and anionic pollutants.

[0021] As one of the preferred technical solutions, the environmental pollutants include: baicalin, Fe 3+ ,CrO 42- .

[0022] The beneficial effects of the present invention are:

[0023] The present invention synthesizes a new metal organic framework compound, which can be used for the treatment of baicalin, Fe 3+ CrO 4 2- The novel metal organic framework compound material synthesized by the present invention has excellent luminescence performance, which can not only identify heavy metal ions Fe among many metal ions, but also can detect environmental pollutants such as ions. 3+ , and can also identify the highly polluting anion CrO 4 2- , and can also identify baicalin molecules among various biological molecules in water. The material has a low detection limit for different ions and molecules, reflecting the advantages of easy preparation, low cost, simple operation, high sensitivity and high selectivity.

[0024] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 is the ligand chemical structural formula of the metal organic framework compound (sample 1) of the present invention;

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

[0028] Figure 3 is the X-ray diffraction pattern of a single crystal;

[0029] Figure 4 is the crystal structure of 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 UV absorption spectra of the main ligand, auxiliary ligand, sample 1 and different molecules;

[0031] Figure 6 It is the fluorescence comparison diagram of sample 1 and different ligands;

[0032] Figure 7 The results of the antimicrobial drug test for sample 1 are shown in Figure 1, where A is a curve graph and B is a bar graph;

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

[0034] Fig. 9 This is the anti-interference bar graph of sample 1 for antimicrobial drug detection;

[0035] Fig.10 This is a comparison chart of the fluorescence cycle data of sample 1 for antibacterial drugs;

[0036] Fig.11 For the screening of cations, A is a curve graph and B is a bar graph;

[0037] Fig.12 To identify the cation concentration titration, A is the fitting graph and B is the curve graph;

[0038] Fig.13 is the anti-interference bar graph for cations;

[0039] Fig.14 It is a comparison chart of fluorescence cycle data of cations;

[0040] Fig.15 For the screening of anions, A is a curve graph and B is a bar graph;

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

[0042] Fig.17 It is the anti-interference bar graph of anions;

[0043] Fig.18 The fluorescence cycle data comparison diagram for anions;

[0044] Fig.19 XRD comparison before and after titration. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with specific implementation modes.

[0046] Example:

[0047] A metal organic framework compound, the molecular formula of which is C 28 H 19 CdN 7 O 4 , the chemical formula is [Cd(L)(bib)]n, where H 2L is 3,5-bis(3'-carboxyphenoxy)-1,2,4-triazole, bib is 1,4-bis(1-imidazolyl)benzene, and their chemical structures are shown in Figure 1 .

[0048] Synthesis method:

[0049] H 2 L(0.1mmol, 0.03g), bib(0.1mmol, 0.021g), Cd(ClO 4 ) 2 6H 2 O (0.15 mmol, 0.06291 g) and 10 mL H 2 The mixture of 2,4-dihydro-1 ... 2 L = 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 ),**wR 2 ={∑[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 Selected hydrogen bond distances and bond angles

[0062]

[0063]

[0064] Crystal structure analysis:

[0065] The analysis of the X-ray single crystal structure shows that sample 1 is composed of the triclinic P-1 space group and presents a one-dimensional chain structure. Combined with the material analysis of the central ion coordination environment, it is found that sample 1 has good symmetry and stability. According to the coordination environment diagram of sample 1 ( Figure 1 ) as shown in the figure, the asymmetric coordination environment unit contains a Cd 2+ , an oxygenated L 2- Ligand anion and one bib ligand molecule. 1 Cd in sample 1 2+ It uses two different CDs. 2+ Composition, each Cd 2+ Each occupies 50%. Cd39 binds to three different carboxylates L 2- The three oxygen atoms O12, O13, O25 of the ligand and two different bib ligands N34 and N55 form a five-coordinated trigonal bipyramidal spatial geometric structure, in which O25 and N34 are located at the vertices and the remaining atoms occupy the equatorial positions of the structure. 2- The four oxygen atoms (O58, O72, O60 and O82) in a carboxyl group in the ligand are coordinated and connected with the two nitrogen atoms (N11 and N33) in the two coordinated bib atoms to form a distorted octahedral geometric structure, in which O58 and N11 are located at the vertices of the octahedron, and the remaining atoms occupy the equatorial positions of the structure.

[0066] Metal Cd 2+ With L 2- The oxygen-containing carboxylic acid coordinated anions adopt chelation and bidentate bridging coordination (coordination mode is μ 3 -η 1 :η 1 :η 1 and μ 2 -η 2 :η 2 ), bib ligand adopts bidentate bridge coordination mode (μ 2 -η1 :η 1 ). The Cd-O bond length in the structure is The bond length of Cd-N is The bond angle of O-Cd-O is in the range of 54.4(5)~153.4(6)°, and the bond angle of O-Cd-N is in the range of 87.0(5)~166.7(4)°. In the structure of sample 1, due to the Cd 2+ Center and L 2- The oxygen-containing ligand anion has two different coordinations, and then forms two different 1D chain structures through the connection of bib auxiliary ligands. The 1D chain structure is then connected through hydrogen bonds such as NH...O, CH...O and CH...N to form a 3D network structure.

[0067] Figure 2 A and B are the infrared and thermogravimetric analysis of the single crystal, respectively. Figure 3 is the X-ray diffraction pattern of single crystal powder. Figure 4 The crystal structure is a single crystal.

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

[0069] See also Figure 3 The results show that in the range of 5-50 (2θ), the theoretical data graph and the experimental measured graph of the sample are consistent in the XRD peak shape and the 2θ position of the peak, indicating that the sample is 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 example

[0071] 1. Antimicrobial drug identification:

[0072] Through experiments with antimicrobial drugs thiamphenicol (THI), furazolidone (FZD), indomethacin (IMC), ciprofloxacin (CIP), pefloxacin (PMD), enrofloxacin (EFA), fleroxacin (FOA), amoxicillin (AMXL), and baicalin (BCL), it was found that sample 1 has sensing properties for BCL antimicrobial drugs. For the sensing experiment, 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 the test. The titration experiment was carried out by gradually adding the aqueous solution of the antimicrobial drug to the aqueous dispersion of sample 1. All experiments were repeated for four cycles. The quenching efficiency was calculated as [(I 0 -I) / I 0 ]×100%, where I 0 and I are the fluorescence intensities before and after the addition of the analyte. These competition experiments were performed by mixing 3 mL of BCL aqueous solution (1 × 10 -3 M) was added to 2 mL of molecular aqueous solution (1×10 -3 M).

[0073] 2. Cation recognition:

[0074] The cation Fe 3+ Has sensing properties. Cation experiments include: magnesium ions (Mg 2+ ), lead ion (Pb 2+ ), zinc ion (Zn 2+ ), nickel ions (Ni 2+ ), potassium ion (K + ), sodium ion (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 min before testing. Titration experiments were performed by gradually adding an aqueous solution of the cations to the aqueous dispersion of sample 1. All experiments were repeated for four cycles. The quenching efficiency was calculated as [(I 0 -I) / I 0 ]×100%, where I 0 and I is the fluorescence intensity before and after the addition of analyte. These competition experiments were performed by 3+ Aqueous solution (1×10 -3 M) was added to 2 mL of molecular aqueous solution (1×10 -3 M).

[0075] 3. Anion recognition:

[0076] Sample 1 and acetate ion (CH 3 COO - ), sulfate ion (SO 4 2- ), sulfite ion (SO 3 2- ), nitrite ions (NO 2- ), nitrate ion (NO 3- ), chlorate ion (ClO 3- ), chromate ion (CrO 4 2- ), fluoride ion (F - ), carbonate ions (CO 3 2- ) was found to have an effect on chromate ions (CrO 4 2- ) has sensing properties. For the sensing experiment, sample 1 (1 mg mL -1 ) dispersion. The titration experiment was performed by gradually adding an aqueous solution of anions to the aqueous dispersion of sample 1. All experiments were repeated for four cycles. The quenching efficiency was calculated as [(I 0 -I) / I 0 ]×100%, where I 0 and I are the fluorescence intensities before and after the addition of the analyte. These competition experiments were performed by adding 3 mL of CrO 4 2- Aqueous solution (1×10 -3 M) was added to 2 mL of molecular aqueous solution (1×10 -3 M).

[0077] The above experimental results are as follows (Table 5):

[0078] 1. Antimicrobial drug experiment:

[0079] Titration (with water as solvent): 0.001mol / 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. Cationic experiment:

[0083] Titration (with water as solvent): 0.0005mol / L Fe3+

[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 (with water as solvent): 0.01mol / L CrO 4 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 drugs, cations, and anions by sample 1

[0091] Titration (σ=0.03124) Kv <![CDATA[R 2 ]]> LOD / (mol / L) 0.001mol / 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 CrO 4 2- ]]> 2918.54 0.98922 <![CDATA[4.81×10 -5 ]]>

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

[0093] Table 6. Identification performance of sample 1 for antimicrobial drugs 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 It can be seen from the UV absorption spectra of ligand compounds and antibacterial drugs that the UV absorption peaks are mainly concentrated in the 200-300nm range, among which H 2 L also has an absorption peak around 315nm.

[0100] from Figure 6The fluorescence comparison chart shows that the fluorescence peaks of sample 1 and ligand bib are basically the same, with a small bulge between 410-470nm at 320nm. Compared with bib, the fluorescence peak of sample 1 is slightly red-shifted. 2 The fluorescence pattern of L is quite different from that of bib and single crystal 1, and its emission peak is mainly in the range of 350-470nm.

[0101] See also Figure 7 ,From the fluorescence screening diagram of sample 1 for antibacterial drugs, it can be seen that the fluorescence intensity of CIP is significantly enhanced, the fluorescence intensities of FZD, EFA, and FOA are significantly weakened, while quenching occurs for BCL, indicating that sample 1 can be used as a potential fluorescent

[0102] See also Figure 8 The quenching of BCL by the sample was studied by concentration titration experiment. The results showed that the luminescence intensity would increase with the increase of BCL concentration, while the fluorescence intensity would gradually weaken.

[0103] The Stern-Volmer equation is used to calculate the relationship between the quenching percentage of the sample luminescence concentration and the concentration of BCL. Figure 8 A. Using linear formula I 0 / I=1+K sv [Q], where K sv represents the sample fluorescence quenching constant, Q represents the different sample quenching concentrations, I 0 is the fluorescence intensity of the blank sample, and I is the fluorescence intensity of the sample at a certain concentration. The quenching of the sample fluorescence intensity is related to the concentration of BCL (from 0 to 8.26×10 -5 mol / L) is an ideal linear relationship. By calculating the Stern-Volmer linear equation, the fluorescence quenching constant (K sv ) was 106319.92, and the fluorescence detection limit (LOD) was 1.32×10 -6 mol / L. Therefore, sample 1 can be used to detect BCL molecules.

[0104] Comparison of the presence of different antimicrobial drugs Fig. 9 It can be seen that in the case of different antimicrobial drugs or antimicrobial drug combinations, the recognition of BCL by sample 1 is not interfered by other antimicrobial drugs. Fig.10 , indicating that sample 1 has no adsorption effect on antimicrobial drugs and has good recycling performance.

[0105] Screening test for cations in sample 1 Fig.11 It can be seen that the common cation Mg 2+ , Pb 2+、Zn 2+ 、Ni 2+ , K + 、Na + 、Cd 2+ The fluorescence intensity of Pb 2+ 、Zn 2+ , K + The fluorescence enhancement is the highest, while the iron ion (Fe 3+ ) showed a very obvious decrease in fluorescence intensity.

[0106] In the titration experiment to identify the concentration of cations ( Fig.12 ) It can be seen that with the Fe 3+ Concentration (0-4.13*10 - 5 mol / L), the fluorescence intensity gradually weakened, and the intensity quenching was related to Fe 3+ The concentration is in a good linear relationship, with a quenching constant of 13228.33 and a LOD of 1.06×10 -5 mol / L.

[0107] Anti-interference experiment on cations Fig.13 It can be seen that other common cations cannot interfere with the Fe 3+ The detection of the cycle test Fig.14 It can be seen that sample 1 has a certain recycling performance. Starting from the third recycling, its performance is slightly reduced, but the impact is not significant.

[0108] Sample 1 for anion screening Fig.15 It can be seen that the common anion CH 3 COO - 、SO 4 2- 、SO 3 2- 、NO 2- 、NO 3- , ClO 3- 、F - , CO 3 2- The fluorescence intensity of ClO 3- and CO 3 2- The enhancement is most obvious, while CrO 4 2- However, obvious fluorescence quenching occurred, so sample 1 can be used as a potential fluorescent probe to detect CrO 4 2- .

[0109] Concentration titration plots and fitting to identify anions Fig.16It can be seen that as the concentration of anions increases, the fluorescence intensity of sample 1 decreases significantly, and the intensity change shows a good linear relationship with the concentration. Through fitting, the quenching constant can be obtained to be 2918.54, and the LOD is 4.81×10 -5 mol / L.

[0110] The anion interference diagram shows that it is not interfered by other anions and their combinations ( Fig.17 ), and can be used cyclically, but after N=3, its performance changes slightly ( Fig.18 ).

[0111] The interference factors in different water qualities are different. The applicant compared the effects of sample 1 in deionized water and different actual water bodies (such as tap water and Fuxi River water) on BCL, Fe 3+ CrO 4 2- By comparing the detection effect with the theoretical value, it was found that the detection effect of BCL has little influence on the water body, but has a greater impact on the detection of cations and anions.

[0112] Titration of BCL, Fe 3+ CrO 4 2- After the experiment, XRD test was performed on sample 1, and it was found that its peak was consistent with the theoretical peak of sample 1, indicating that during the titration test, sample 1 did not adsorb the analyte and did not undergo any structural changes. Fig.19 )

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A metal organic framework compound, characterized in that The chemical formula of the compound is [Cd(H2L)(bib)]n, wherein 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 the compound belongs to the triclinic system, the space group is P-1, and the unit cell parameters are: bond length Key length Key length Bond angle α = 93.211 (12)°, bond angle β = 91.972 (11)°, bond angle γ = 111.877 (10)°.

2. A 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, unit cell volume The number of molecules in the unit cell is Z = 4, and the crystal density is ρ calcd =1.672g / cm 3 , linear absorption coefficient μ=0.924mm –1 , the number of electrons in the unit cell F(000) = 1264, the unit cell diffraction angle range θRange = 1.0-25.0deg, the diffraction point collection = 8732, the independent diffraction point (R int )=0.000, the number of diffractions with intensity greater than 2σ=5582.

5. The 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 to 45 minutes, then transfer and seal in a reactor, heat to 110 to 140°C, keep warm for 68 to 80 hours, and cool to room temperature to obtain the product; wherein the molar ratio of H2L, bib and Cd(ClO4)2·6H2O is 2:2:2.7 to 3.6, the amount ratio of H2L and water is 0.1 mmol:9 to 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°C / h, and the cooling rate is 3-8°C / h.

7. Use of a metal organic framework compound as claimed in any one of claims 1 to 4 in the detection of environmental pollutants.

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

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

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