Zn (II)-based metal organic framework crystalline material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of fluorescence sensing, in particular to a Zn (II)-based metal organic framework crystalline material as well as a preparation method and application thereof. Zinc chloride and H3 (5-COIA) ligands are added into DMA, pH is adjusted, the Zn (II)-based metal organic framework material with a novel structure is prepared through a solvothermal method, the preparation method has the advantages of being convenient to operate, high in yield, good in reproducibility and the like, and the Zn (II)-based metal organic framework material has very strong fluorescence emission performance and good water stability and can be used for preparing a fluorescent material with a novel structure. It has been studied to selectively and sensitively detect La3 + ions in aqueous solutions, thereby further protecting human health and the environment from these contaminants.

Description

Technical Field

[0001] The present invention relates to the field of fluorescence sensing technology, and in particular to a Zn(II)-based metal organic framework crystalline material and a preparation method and application thereof. Background Art

[0002] Metal-organic frameworks (MOFs) are organic-inorganic hybrid materials with a crystalline porous network structure formed by the coordination of metal ions and organic ligands. They combine the rigidity of inorganic materials with the flexibility of organic materials, making them show great potential in attractive applications. To date, MOFs with high porosity, tunable size and controllable structure have been rapidly developed and have a wide range of applications in separation, catalysis, energy, biomedicine and sensing.

[0003] Sensors are devices that enable simple, rapid, selective, and sensitive detection. As an ideal sensing material, it should be stable and highly sensitive to the target analyte without interference from other possible substances. MOFs have great tunability and functionalization potential. By changing the metal ions and organic ligands, the porosity and composition of MOFs can be adjusted, thereby changing their luminescence and chemical-physical properties.

[0004] La 3+ is a transition metal ion that can be used in radiotherapy applications, catalysis, and the synthesis of nanomaterials. In addition, due to their equal size, La 3+ Ca in proteins 2+ The binding sites bind strongly. As lanthanum compounds are increasingly used in industry, their release into the environment poses a greater threat to life. Therefore, accurate determination of La 3+ It is of great significance for human health and environmental monitoring. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a Zn(II)-based metal organic framework crystalline material and its preparation method and application in view of the above-mentioned deficiencies in the prior art. The Zn(II)-based metal organic framework crystalline material has a space group of P-1 and belongs to the triclinic system. The minimum asymmetric unit consists of three Zn(II) ions, two deprotonated 5-COIA 3- The Zn1 is composed of two oxygen atoms from two monodentate coordinated water molecules and four 5-COIA 3- The four oxygen atoms of the ligand are hexacoordinated, and Zn2 is coordinated with the oxygen from a monodentate water molecule and from three 5-COIA atoms. 3-The oxygen atom of the ligand is hexacoordinated with a nitrogen atom on a pyridazine ring, Zn3 is monodentately coordinated with an oxygen atom in a water molecule, and two 5-COIA 3- The oxygen atom of the ligand is five-coordinated with the nitrogen atom on the pyridazine ring. Each independent Zn2 and Zn3 has the same connection mode, all through 5-COIA 3- Ligand connected, Zn2 and Zn3 through 5-COIA 3- The two carboxyl oxygen groups on the benzene ring of the ligand coordinate to form a one-dimensional chain, and the Zn3 and Zn2 between the chains are linked through Zn1 to form a two-dimensional surface.

[0006] The present invention provides a Zn(II)-based metal organic framework crystalline material, wherein the chemical expression of the Zn(II)-based metal organic framework crystalline material is [Zn 3 (H 2 O) 4 (5-COIA) 2 ] n The molecular formula of the Zn(II)-based metal organic framework crystalline material is C 26 H 18 N 4 O 18 Zn 3 .

[0007] The present invention provides a method for preparing the above-mentioned Zn(II)-based metal organic framework crystalline material, comprising the following steps: S1, zinc chloride and H 3 (5-COIA) is added to DMA to obtain a mixed solution, and after the pH value of the mixed solution is adjusted to 3.6 to 4.2, the mixed solution is fully reacted at a temperature of 90 to 95°C to obtain a primary product; S2, cooling the primary product prepared in S1 to crystallize, and washing, filtering and drying the precipitated crystals in sequence to obtain a Zn(II)-based metal organic framework crystalline material.

[0008] According to the method for preparing a Zn(II)-based metal organic framework crystalline material provided by the present invention, the zinc chloride, H 3 The molar volume ratio of (5-COIA) to DMA is 0.4 mmol:0.1 mmol:2 mL, and the sufficient reaction time is 50 to 54 h.

[0009] According to the preparation method of Zn(II)-based metal organic framework crystalline material provided by the present invention, the rinsing agent in S2 is deionized water, the filtration is reduced pressure filtration, and the drying is constant temperature drying in an oven at 40°C for 3 to 5 hours.

[0010] The present invention also provides an application of the above Zn(II)-based metal organic framework crystalline material, wherein the Zn(II)-based metal organic framework crystalline material is used to selectively and sensitively detect La in aqueous solution. 3+ ion.

[0011] [Zn 3 (H 2 O) 4 (5-COIA) 2 ] n The minimum asymmetric unit consists of three Zn(Ⅱ) ions, two deprotonated 5-COIA 3- The Zn1 is composed of two oxygen atoms from two monodentate coordinated water molecules and four 5-COIA 3- The four oxygen atoms of the ligand are hexacoordinated, and Zn2 is coordinated with the oxygen from a monodentate water molecule and from three 5-COIA atoms. 3- The oxygen atom of the ligand is hexacoordinated with a nitrogen atom on a pyridazine ring, Zn3 is monodentately coordinated with an oxygen atom in a water molecule, and two 5-COIA 3- The oxygen atom of the ligand is five-coordinated with the nitrogen atom on the pyridazine ring. Each independent Zn2 and Zn3 has the same connection mode, all through 5-COIA 3- Ligand connected, Zn2 and Zn3 through 5-COIA 3- The two carboxyl oxygen groups on the benzene ring of the ligand are coordinated to form a one-dimensional chain, and the Zn3 and Zn2 between the chains are linked by the Zn1 phase to form a two-dimensional surface. The Zn(II)-based metal organic framework crystalline material belongs to the triclinic system and P-1 space group, with unit cell parameters of a=8.0250(14)Å, b=15.965(2)Å, c=17.301(3)Å, α=66.649(5)°, β=82.852(9)°, γ=75.924(7)°, V=1973.0(5)Å 3 .

[0012] Compared with the prior art, the present invention has the following advantages: (1) The present invention adopts a one-pot solvent thermal reaction to prepare the Zn(II)-based metal organic framework crystalline material [Zn 3 (H 2 O) 4 (5-COIA) 2 ] n The preparation method has the advantages of simple process, convenient operation, high yield and good reproducibility.

[0013] (2) The Zn(II)-based metal organic framework crystalline material of the present invention has strong fluorescence emission performance and good water stability, and has been studied for selective and sensitive detection of La in aqueous solution.3+ ions, thereby further protecting human health and the environment from these pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a single molecule image of the Zn(II)-based metal organic framework crystalline material prepared in Example 2; Figure 2 This is a three-dimensional supramolecular structure diagram of the Zn(II)-based metal organic framework crystalline material prepared in Example 2; Figure 3 is the IR graph of the Zn(II)-based metal organic framework crystalline material prepared in Example 2; Figure 4 is the XRD pattern of the Zn(II)-based metal organic framework crystalline material prepared in Example 2; Figure 5 is a fluorescence enhancement diagram of the Zn(II)-based metal organic framework crystalline material prepared in Example 2; Figure 6 This is a fitting diagram of the fluorescence change value of the Zn(II)-based metal organic framework crystalline material prepared in Example 2; Figure 7 This is a diagram of other ion anti-interference of the Zn(II)-based metal organic framework crystalline material prepared in Example 2. DETAILED DESCRIPTION

[0015] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0016] The present invention provides a method for preparing a Zn(II)-based metal organic framework crystalline material, which specifically comprises the following steps: S1. Mix 0.4 mmol of zinc chloride and 0.1 mmol of H 3 (5-COIA) was added to 2 mL of DMA (dimethylacetamide) to obtain a mixed solution. After the pH value of the mixed solution was adjusted to 3.6-4.2, the mixed solution was fully solvothermally reacted in a glass scintillation vial at a temperature of 90-95 °C for 50-54 h to obtain an intermediate product. S2, naturally cooling the intermediate product prepared in S1 to crystallize, and the precipitated crystals are successively rinsed with deionized water and filtered under reduced pressure to obtain transparent block crystals, which are then placed in an oven at a temperature of 40°C and dried at a constant temperature for 3 to 5 hours to obtain a Zn(II)-based metal organic framework crystalline material [Zn 3 (H 2 O) 4 (5-COIA) 2 ] n .

[0017] The preparation method provided by the present invention has the advantages of convenient operation, high yield, good reproducibility, etc. The prepared Zn(II)-based metal organic framework crystalline material has strong solid fluorescence emission performance and good water stability, and has been studied for selective and sensitive detection of La in aqueous solution. 3+ ions, thereby further protecting human health and the environment from these pollutants.

[0018] Example 1

[0019] This embodiment provides a method for preparing a Zn(II)-based metal organic framework crystalline material, and the specific steps are as follows: S1. Mix 0.4 mmol of zinc chloride and 0.1 mmol of H 3 (5-COIA) was added to 2 mL of DMA (dimethylacetamide) to obtain a mixed solution, and the pH value of the mixed solution was adjusted to 3.6 with a 0.3 mol / L nitric acid solution. The mixed solution was fully solvothermally reacted in a glass scintillation vial at 90 °C for 54 h to obtain an intermediate product. S2. Naturally cool the intermediate product prepared in S1 and crystallize it. The precipitated crystals are rinsed with deionized water and filtered under reduced pressure to obtain transparent block crystals, which are then placed in an oven at 40°C and dried at a constant temperature for 3 h to obtain a Zn(II)-based metal organic framework crystalline material with a yield of 76.4%.

[0020] Example 2

[0021] This embodiment provides a method for preparing a Zn(II)-based metal organic framework crystalline material, and the specific steps are as follows: S1. Mix 0.4 mmol of zinc chloride and 0.1 mmol of H 3 (5-COIA) was added to 2 mL of DMA (dimethylacetamide) to obtain a mixed solution, and the pH value of the mixed solution was adjusted to 3.8 with a 0.3 mol / L nitric acid solution. The mixed solution was fully solvothermally reacted in a glass scintillation vial at 93 °C for 52 h to obtain an intermediate product. S2. Naturally cool the intermediate product prepared in S1 to crystallize, rinse the precipitated crystals with deionized water and filter under reduced pressure to obtain transparent block crystals, which are then placed in an oven at 40°C and dried at a constant temperature for 3 h to obtain a Zn(II)-based metal organic framework crystalline material with a yield of 79.5%.

[0022] Example 3

[0023] This embodiment provides a method for preparing a Zn(II)-based metal organic framework crystalline material, and the specific steps are as follows: S1. Mix 0.4 mmol of zinc chloride and 0.1 mmol of H 3 (5-COIA) was added to 2 mL of DMA (dimethylacetamide) to obtain a mixed solution, and the pH value of the mixed solution was adjusted to 4.2 with a 0.3 mol / L nitric acid solution. The mixed solution was fully solvothermally reacted in a glass scintillation vial at 95 °C for 50 h to obtain an intermediate product. S2. Naturally cool the intermediate product prepared in S1 to crystallize, rinse the precipitated crystals with deionized water and filter under reduced pressure to obtain transparent block crystals, which are then placed in an oven at 40°C and dried at a constant temperature for 3 h to obtain a Zn(II)-based metal organic framework crystalline material with a yield of 77.3%.

[0024] Example 4

[0025] The Zn(II)-based metal organic framework crystalline material prepared in Example 1 was characterized as follows: ① Crystal structure determination of coordination polymer: Under a microscope, a single crystal with a suitable size of 0.200×0.230×0.250 mm was selected for X-ray diffraction experiments at room temperature. Diffraction data were collected on a Bruker-ApexП X-ray single crystal diffractometer. Mo-Kα rays (λ= 0.71073 Å) were monochromatized by a graphite monochromator, and diffraction points were collected in an ω-2θ scanning mode. All data were corrected by factors and empirical absorption. The crystal structure was solved by a direct method using a program. Hydrogen atoms were determined by difference Fourier synthesis and fixed in the calculated optimal position. Using the SHELX-97 program, all non-hydrogen atoms and their anisotropic thermal parameters were corrected based on the full-matrix least squares method. Detailed crystal measurement data are shown in Table 1, important bond length and bond angle data are shown in Table 2, and the crystal structure is shown in Table 2. Figure 1 As shown in Figure 2, observing the three-dimensional supramolecular structure of the polymer from the c-axis direction, obvious molecular channels can be seen, such as Figure 2 shown.

[0026] Table 1 Main crystallographic data of Zn(II)-based metal-organic framework crystalline materials

[0027] Table 2 Important bond lengths (Å) and bond angles (°) of Zn(II)-based metal-organic framework crystalline materials

[0028] In Table 1, a, b and c represent the edge lengths of the crystal in the directions of the three crystal axes, respectively, and α, β and γ represent the angles between a and b, a and c, and b and c, respectively; Zis the number of molecules contained in the unit cell; the diffraction index range of the limiting factor is (h, k, l); F (000) is the number of electrons in the unit cell; Final R indices I >2σ( I )] is the residual factor R value for the observable diffraction point; R is the non-weighted consistency factor; R 1 and wR 2 All are weight consistency factors; In the first row of Table 2, Zn(1) refers to Zn atom 1 in the Zn(II)-based metal organic framework crystalline material single crystal, N(1) refers to N atom 1 in the Zn(II)-based metal organic framework crystalline material single crystal, and Zn(1)-N(1) represents the bond length between Zn atom 1 and N atom 1, which is 2.431±9, with 9 being the standard deviation; O(2)-Zn(1)-N(2) represents the bond angle between O atom 2, Zn atom 1 and N atom 2, and its bond angle is 70.8±3; Each minimum asymmetric unit consists of three Zn(II) ions, two deprotonated 5-COIA 3- The Zn1 is composed of two oxygen atoms from two monodentate coordinated water molecules and four 5-COIA 3- The four oxygen atoms of the ligand are hexacoordinated, and Zn2 is coordinated with the oxygen from a monodentate water molecule and from three 5-COIA atoms. 3- The oxygen atom of the ligand is hexacoordinated with a nitrogen atom on a pyridazine ring, Zn3 is monodentately coordinated with an oxygen atom in a water molecule, and two 5-COIA 3- The oxygen atom of the ligand is five-coordinated with the nitrogen atom on the pyridazine ring. Each independent Zn2 and Zn3 has the same connection mode, all through 5-COIA 3- Ligand connected, Zn2 and Zn3 through 5-COIA 3- The two carboxyl oxygen groups on the benzene ring of the ligand are coordinated to form a one-dimensional chain, and the Zn3 and Zn2 between the chains are linked by the Zn1 phase to form a two-dimensional surface. The Zn(II)-based metal organic framework crystalline material belongs to the triclinic system and P-1 space group, with unit cell parameters of a=8.0250(14)Å, b=15.965(2)Å, c=17.301(3)Å, α=66.649(5)°, β=82.852(9)°, γ=75.924(7)°, V=1973.0(5)Å 3 .

[0029] ②IR spectrum characterization: Figure 3This is the IR spectrum of Zn(II)-based metal organic framework crystalline material. The sample infrared spectrum data collection range is 500-4000 cm -1 , using KBr tablets. Figure 3 It can be seen that 1401~1631 cm -1 The peak between is the benzene ring stretching vibration peak, 3127cm -1 It is the stretching vibration peak of the OH bond in the water molecule.

[0030] The molecular formula of the Zn(II)-based metal organic framework crystalline material prepared in Example 2 is [Zn 3 (H 2 O) 4 (5-COIA) 2 ] n , n is 10 12 ~10 18 .

[0031] ③Phase purity characterization of Zn(II)-based metal organic framework crystalline materials: Using a Bruker / D8Advance X-ray diffractometer, the powder XRD characterization results of Zn(II)-based metal organic framework crystalline materials showed that they have reliable phase purity, which provides a guarantee for their application as catalysts, such as Figure 4 shown.

[0032] ④ Fluorescence sensing characterization of Zn(II)-based metal-organic framework crystalline materials La 3+ Add uniformly dispersed in the aqueous solution of Zn(II)-based metal organic framework crystalline material according to the gradient, such as Figure 5 As shown, with La 3+ With the increase of concentration, the fluorescence emission intensity of Zn(II)-based metal organic framework crystalline materials at 530 nm increased significantly. Figure 6 As shown in the figure, the fluorescence intensity of Zn(II)-based metal organic framework crystalline material fluorescence sensing is related to La 3+ The concentration showed a good linear relationship (R 2 =0.9995). At the same time, the fluorescence changes of Zn(II)-based metal organic framework crystalline materials in the presence of 13 interfering ions were evaluated, such as Figure 7 As shown in Figure 2, the fluorescence intensity of Zn(II)-based metal organic framework crystalline materials in the presence of interfering ions is almost the same as that of La alone. 3+ The results show that La in mixed metal ion aqueous solution can be effectively detected. 3+ ion.

[0033] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A Zn(II)-based metal organic framework crystalline material, characterized in that: The chemical expression of the Zn(II)-based metal organic framework crystalline material is [Zn3(H2O)4(5-COIA)2] n The molecular formula of the Zn(II)-based metal organic framework crystalline material is C 26 H 18 N4O 18 Zn3.

2. A method for preparing the Zn(II)-based metal organic framework crystalline material as claimed in claim 1, characterized in that: The following steps are involved: S1. Add zinc chloride and H3(5-COIA) to DMA to obtain a mixed solution, adjust the pH value of the mixed solution to 3.6-4.2, and then fully react at a temperature of 90-95°C to obtain a primary product; S2, cooling the primary product prepared in S1 to crystallize, and washing, filtering and drying the precipitated crystals in sequence to obtain a Zn(II)-based metal organic framework crystalline material.

3. The method for preparing the Zn(II)-based metal organic framework crystalline material according to claim 2, characterized in that: The molar volume ratio of zinc chloride, H3(5-COIA) and DMA in S1 is 0.4 mmol:0.1 mmol:2 mL, and the sufficient reaction time is 50 to 54 h.

4. The method for preparing the Zn(II)-based metal organic framework crystalline material according to claim 2, characterized in that: The rinsing agent in S2 is deionized water, the filtration is reduced pressure filtration, and the drying is constant temperature drying in an oven at 40° C. for 3 to 5 hours.

5. An application of the Zn(II)-based metal organic framework crystalline material as claimed in claim 1, characterized in that: The Zn(II)-based metal organic framework crystalline material is used for selective and sensitive detection of La in aqueous solution 3+ ion.

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