A Zn(II) coordination polymer crystalline material and its preparation method and application

Abstract

The present invention relates to the field of fluorescence sensing technology, and more particularly to a Zn(II) coordination polymer crystalline material, its preparation method, and its application. The present invention utilizes a one-pot solvent thermal reaction to prepare a Zn(II) ion coordination polymer crystalline material {[Zn2(H2O)6(DODDA)]·4H2O} n The preparation method has the advantages of simple process, convenient operation, high yield and good reproducibility. Zn(II) coordination polymer crystalline material has strong fluorescence emission performance and good water stability, which can be used to selectively and sensitively detect Cu in aqueous solution. 2+ ions, thereby further protecting human health and the environment from the harm of these pollutants.

Description

Technical Field

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

[0002] In recent years, Zn(II) coordination polymer crystalline materials have demonstrated significant application value in environmental monitoring, bioimaging, and medical diagnosis due to their unique luminescence properties and excellent selective recognition capabilities. As the second most essential trace element for the human body, abnormal concentrations of Zn(II) ions are closely associated with a variety of neurological diseases. Therefore, the development of highly sensitive and selective Zn(II) coordination polymer crystalline materials is of great significance. Compared with traditional small molecule fluorescent probes, Zn(II) sensing materials based on coordination polymers have significant advantages such as strong structural designability and good stability. Among them, Zn(II) complexes such as metal-organic frameworks (MOFs) and coordination polymers can achieve specific recognition and signal amplification of Zn(II) due to their tunable pore structures and abundant coordination sites, with detection limits reaching nanomolar levels. However, existing Zn(II) coordination fluorescent materials still face challenges such as poor water solubility, insufficient cell membrane permeability, and limited anti-interference ability.

[0003] In recent years, the detection and removal of heavy metal ions have gained significant importance in fields such as environmental monitoring, biomedicine, and industrial wastewater treatment. Excessive accumulation of divalent copper ions, essential trace elements for life, can cause serious environmental and health problems, such as neurodegenerative diseases and ecotoxicity. Consequently, the development of efficient, sensitive, and selective Cu²⁺ detection methods has become a research hotspot. Fluorescence sensing technology, due to its ease of operation, rapid response, and high sensitivity, has been widely used for the identification and detection of metal ions.

[0004] Currently, the sensing properties of Zn(II) coordination polymers for Cu²⁺, such as static quenching, dynamic quenching, or structural transformation, require further clarification. Furthermore, improving the material's water stability, anti-interference properties, and low detection limits remain challenges for practical applications. Therefore, developing novel Zn(II) coordination polymers and optimizing their sensing properties are crucial for advancing heavy metal ion detection technology. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and provide a Zn(II) coordination polymer crystalline material and its preparation method and application. The Zn(II) ion coordination polymer crystalline material {[Zn2(H2O)6(DODDA)]·4H2O} can be prepared by a one-pot solvent thermal reaction. nThe preparation method has the advantages of simple process, convenient operation, high yield and good reproducibility. The Zn(II) coordination polymer crystalline material has strong fluorescence emission performance and good water stability, which can be used for selective and sensitive detection of Cu in aqueous solution. 2+ ions, thereby further protecting human health and the environment from the harm of these pollutants.

[0006] The present invention provides a Zn(II) coordination polymer crystalline material, wherein the single crystal molecular formula of the Zn(II) coordination polymer crystalline material is C 14 H 20 N2O 17 Zn2, the chemical formula of the Zn(II) coordination polymer crystalline material is {[Zn2(H2O)6(DODDA)]·4H2O} n .

[0007] According to the Zn(II) coordination polymer crystalline material provided by the present invention, the Zn(II) coordination polymer crystalline material is an orthorhombic crystal system, the space group is Imma, and the unit cell parameters include a=21.3223(6) Å, b=26.1017(8) Å, c=7.2108(2)Å, α=90.00°, β=90.00° and γ=90.00°.

[0008] The present invention provides a method for preparing the above-mentioned Zn(II) coordination polymer crystalline material, comprising the following steps:

[0009] S1. Add H4(DODDA) and zinc salt to DMA to obtain a mixed solution, keep the solution at a constant temperature for sufficient reaction, and then allow the solution to stand to obtain a reaction product;

[0010] S2. Cooling the reaction product obtained in S1 to crystallize, and washing, filtering and drying the crystallized product in sequence to obtain a Zn(II) coordination polymer crystalline material.

[0011] According to the preparation method provided by the present invention, the H4 (DODDA) in S1 is 1-(3,5-dicarboxyphenyl)-4-oxo-1,4-dihydropyridazine-3,5-dicarboxylic acid, and the structural formula of the H4 (DODDA) is:

[0012] .

[0013] According to the preparation method provided by the present invention, the zinc salt in S1 is zinc nitrate hexahydrate, and the mass volume ratio of the H4(DODDA), zinc salt and DMA is 0.1 mmol:0.1 mmol:2 mL.

[0014] According to the preparation method provided by the present invention, the temperature of the constant temperature full reaction in S1 is 80-95°C, the time of the constant temperature full reaction is 45-50 hours, and the standing time is 12 hours.

[0015] According to the preparation method provided by the present invention, the rinsing agent in S2 is deionized water, the filtration is reduced-pressure filtration, the drying temperature is 60° C., and the drying time is 2 to 4 h.

[0016] The present invention also provides an application of the Zn(II) coordination polymer crystalline material, wherein the Zn(II) coordination polymer crystalline material is used for selectively and sensitively detecting Cu in aqueous solution. 2+ ion.

[0017] The molecular formula of Zn(II) coordination polymer crystalline material is {[Zn2(H2O)6(DODDA)]·4H2O} n , which uses Zn(II) ions as connecting nodes and H4(DODDA) ligands as bridging ligands to bridge each other; its asymmetric unit contains two Zn(II) ions with different coordination modes, a deprotonated DODDA 4- The Zn1 ion center is connected to the two carboxyl oxygens and four monodentate coordinated waters of the H4(DODDA) ligand. Both Zn1 and Zn2 ions have a hexacoordinate structure, but unlike the coordination environment of Zn1, the Zn2 ion is connected to two monodentate coordinated water molecules and four oxygen atoms from the carbonyl and carboxyl groups. The adjacent Zn1 ions and the two deprotonated tetracarboxyl ligands form an "H"-shaped secondary structural unit through a "head-to-head" chelate coordination form. This secondary structural unit connects different Zn2 ions through a four-connection mode to form a horizontal ladder-shaped one-dimensional chain. The one-dimensional chains form a three-dimensional supramolecular structure through a large number of intermolecular hydrogen bonds. Among them, H4(DODDA) is 1-(3,5-dicarboxyphenyl)-4-oxo-1,4-dihydropyridazine-3,5-dicarboxylic acid, and n is a positive integer.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The present invention provides a Zn(II) coordination polymer crystalline material and its preparation method and application. The Zn(II) ion coordination polymer crystalline material {[Zn2(H2O)6(DODDA)]·4H2O} can be prepared by a one-pot solvent thermal reaction. n The preparation method has the advantages of simple process, convenient operation, high yield and good reproducibility.

[0020] Zn(II) coordination polymer crystalline materials have strong fluorescence emission properties and good water stability, which can be used for selective and sensitive detection of Cu in aqueous solution. 2+ ions, thereby further protecting human health and the environment from the harm of these pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a single molecule image of the Zn(II) coordination polymer crystalline material 1;

[0022] Figure 2 It is the three-dimensional supramolecular structure of Zn(II) coordination polymer;

[0023] Figure 3 IR spectrum of Zn(II) coordination polymer crystalline material 1;

[0024] Figure 4 is the XRD pattern of Zn(II) coordination polymer crystalline material 1;

[0025] Figure 5 This is a solid-state fluorescence spectrum of the Zn(II) coordination polymer crystalline material 1;

[0026] Figure 6 This is a graph of the fluorescence emission intensity of Zn(II) coordination polymer crystalline material 1 dispersed in different organic solvents;

[0027] Figure 7 Different volumes of Cu were added to the Zn(II) coordination polymer crystalline material 1 in deionized water. 2+ Fluorescence spectrum after solution (0.01mmol / L);

[0028] Figure 8 Zn(II) coordination polymer crystalline material 1 on Cu 2+ Linear fitting graph of fluorescence change values ​​in solution (0.01 mmol / L);

[0029] Figure 9 This is the fluorescence emission intensity diagram of Zn(II) coordination polymer crystalline material 1 in different ion solutions. DETAILED DESCRIPTION

[0030] Example 1

[0031] This embodiment provides a method for preparing H4(DODDA), and the specific steps are as follows:

[0032] S1. Dissolve 12.00 g of diethyl 5-aminoisophthalate in 110 mL of distilled water. Add 50 mL of concentrated hydrochloric acid and 20 mL of 3 mol / L NaNO2 solution dropwise at 0°C in an ice bath to obtain a clear yellow diazonium salt solution.

[0033] S2. Under an ice bath, 0.15 mol of sodium acetate was dissolved in 300 mL of distilled water and 300 mL of anhydrous ethanol and stirred for 15 min. Then, 11.30 g of diethyl 1,3-acetonedicarboxylate was added and stirring was continued for 15 min. Then, the diazonium salt solution prepared in S1 was slowly added and the reaction was continued for 2 hours. The mixture was filtered and the filter cake was washed until neutral. The filter cake was dried at room temperature to obtain diethyl 2-(2-(3,5-diethoxycarbonylphenyl)hydrazino)-3-oxoglutarate.

[0034] S3, dissolve the diethyl 2-(2-(3,5-diethoxycarbonylphenyl)hydrazine)-3-oxoglutarate obtained in S2 in toluene, and add 6.19 g DMF-DMA ( N , N -dimethylformamide dimethyl acetal), then react at 100 ° C for 12 hours, concentrate to remove toluene, and obtain a black-red viscous substance 1-(3,5-diethoxycarbonylphenyl)-4-oxo-1,4-dihydropyridazine-3,5-dicarboxylic acid diethyl ester;

[0035] S4. Dissolve the diethyl 1-(3,5-diethoxycarbonylphenyl)-4-oxo-1,4-dihydropyridazine-3,5-dicarboxylate obtained in S3 in 100 mL of distilled water, add 16.64 g of NaOH solid and stir, heat the reaction system to 60 °C and react for 3 h, cool to room temperature, add 150 mL of distilled water to the system, add HCl solution to adjust the pH to 2, filter, wash the filter cake to neutrality, and dry to obtain 1-(3,5-dicarboxyphenyl)-4-oxo-1,4-dihydropyridazine-3,5-dicarboxylic acid, i.e., H4(DODDA).

[0036] The preparation steps are specifically shown in the following formula:

[0037] .

[0038] Example 2

[0039] This embodiment provides a method for preparing a Zn(II) coordination polymer crystalline material, comprising the following steps:

[0040] S1, 0.1 mmol of zinc nitrate hexahydrate, 0.1 mmol of 1-(3,5-dicarboxyphenyl)-4-oxo-1,4-dihydropyridazine-3,5-dicarboxylic acid (H4(DODDA)) and 2 mL N , N -dimethylacetamide (DMA) to obtain a mixture, the mixture was subjected to solvothermal reaction at 80 °C in a glass scintillation vial for 48 h, and then allowed to stand for 12 h to obtain a reaction product;

[0041] S2. The reaction product was naturally cooled and crystallized, and then washed with deionized water and filtered under reduced pressure to obtain transparent block crystals. The crystals were placed in an oven at 60 °C for 3 h to obtain Zn(II) coordination polymer crystalline material 1 with a yield of about 71.2%.

[0042] Example 3

[0043] This embodiment provides a method for preparing a Zn(II) coordination polymer crystalline material, comprising the following steps:

[0044] S1. 0.1 mmol of zinc nitrate hexahydrate, 0.1 mmol of H4(DODDA), and 2 mL of DMA were mixed to obtain a mixture. The mixture was subjected to a solvothermal reaction at 90°C in a glass scintillation vial for 45 h, and allowed to stand for 12 h to obtain a reaction product.

[0045] S2. The reaction product was naturally cooled and crystallized, rinsed with deionized water and filtered under reduced pressure to obtain transparent block crystals. The crystals were placed in an oven at 60 °C for 5 h to obtain Zn(II) coordination polymer crystalline material 2 with a yield of about 70.5%.

[0046] Example 4

[0047] This embodiment provides a method for preparing a Zn(II) coordination polymer crystalline material, comprising the following steps:

[0048] S1. 0.1 mmol of zinc nitrate hexahydrate, 0.1 mmol of H4(DODDA), and 2 mL of DMA were mixed to obtain a mixture. The mixture was subjected to a solvothermal reaction at 85°C in a glass scintillation vial for 50 h, and then allowed to stand for 12 h to obtain a reaction product.

[0049] S2. The reaction product was naturally cooled and crystallized, rinsed with deionized water and filtered under reduced pressure to obtain transparent block crystals. The crystals were placed in an oven at 60 °C for 4 h to obtain Zn(II) coordination polymer crystalline material 3 with a yield of about 69.2%.

[0050] Example 5

[0051] The Zn(II) coordination polymer crystalline material 1 prepared in Example 2 was characterized as follows:

[0052] (1) Crystal structure determination of Zn(II) coordination polymer crystalline materials

[0053] Select the appropriate size of 0.32×0.28×0.25 mm under the microscope 3X-ray diffraction experiments were performed on single crystals at room temperature. Diffraction data were collected on a Bruker P4 CCD single crystal diffractometer and monochromated with a graphite monochromator. Mo-Kα ray (λ = 0.71073 Å), with φ-ω The diffraction points were collected in a scanning mode. In addition, the absorption correction and factor correction of Lp were performed using the SADABS program. All non-hydrogen atoms and their anisotropic thermal parameters were corrected based on the full matrix least squares method using the SHELX-97 program. Detailed crystallographic measurement data are shown in Table 1, and bond length and bond angle data are shown in Table 2. Figure 1-2 shown.

[0054] Table 1

[0055]

[0056] Table 2

[0057]

[0058] Symmetric code: 1 1 / 2-X,1 / 2-Y,3 / 2-Z; 2 +X,1 / 2-Y,+Z;

[0059] In Table 1, a, b, and c represent the edge lengths of the crystal in the directions of the three crystal axes, respectively; α, β, and γ represent the angles between a and b, a and c, and b and c, respectively; Z is 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; R1 and wR2 are both weighted consistency factors;

[0060] In the first row of Table 2, Zn(1) refers to Zn atom 1 in the single crystal of Zn(II) coordination polymer crystalline material 1, O(3) refers to O atom 3 in the single crystal of Zn(II) coordination polymer crystalline material 1, and Zn(1)-O(3) represents the bond length between Zn atom 1 and O atom 3, which is 1.129±2, with 2 being the standard deviation; O(3)-Zn(1)-O(3) 1 It represents the bond angle between O atom 3, Zn atom 1 and the symmetric atom 1 of O atom 3, and its bond angle is 78.11±15;

[0061] (1) IR spectrum characterization of Zn(II) coordination polymer crystalline material 1

[0062] Figure 3 This is the IR spectrum of Zn(II) coordination polymer crystalline material 1. The infrared spectrum of the sample was collected from 4000 to 400 cm -1, using KBr pellets.

[0063] Depend on Figure 3 It can be seen that the Zn(II) coordination polymer crystalline material 1 has a peak at 3162 cm -1 There is a strong broad absorption peak at 1608~1562 cm, which is the stretching vibration peak of OH group. -1 The asymmetric and symmetric stretching vibrations of the carbonyl group are shown.

[0064] (2) Phase purity characterization of Zn(II) coordination polymer crystalline material 1

[0065] The powder XRD characterization results of Zn(II) coordination polymer crystalline material 1 using Bruker / D8Advance X-ray diffractometer showed that it has reliable phase purity, which provides a guarantee for its use as a fluorescent probe to detect excessive organic pollutants, pesticides, and heavy metal ions emitted in the environment. Figure 4 shown.

[0066] (3) Fluorescence sensing characterization of Zn(II) coordination polymer crystalline material 1

[0067] The solid fluorescence properties of Zn(II) coordination polymer crystalline material 1 were tested using Edinburgh instruments / FLS 1000 fluorescence spectrometer. The fluorescence lifetime of Zn(II) coordination polymer crystalline material 1 is shown in Figure 2. Figure 5 shown.

[0068] 2.0 mg of the fully ground Zn(II) coordination polymer crystalline material 1 prepared in Example 1 was weighed and placed in 7 3 mL organic solvents respectively. After ultrasonication for half an hour and standing for one hour, the supernatant was taken and placed in a cuvette.

[0069] At an excitation wavelength of 347 nm, the ions were detected in water (H2O), ethanol (EtOH), acetonitrile (CAN), N , N -dimethylformamide (DMF), N , N -dimethylacetamide (DMA), N , N -diethylformamide (DEF), N , N -Diethylacetamide (DEA), as the fluorescence emission intensity of the suspension in the solvent, such as Figure 6 shown.

[0070] Depend on Figure 6 It can be seen that the fluorescence intensity of Zn(II) coordination polymer crystalline material 1 is the strongest in deionized water. N ,N -The fluorescence intensity in dimethylformamide (DMF) solvent is the lowest.

[0071] 2 mg of the fully ground crystalline powder of the Zn(II) coordination polymer crystalline material 1 prepared in Example 1 was placed in 4 mL of aqueous solution, sonicated for half an hour and allowed to stand for one hour, and then 3 mL of the supernatant was placed in a cuvette.

[0072] At an excitation wavelength of 410 nm, Cu 2+ 3 μL was sequentially added to the supernatant of Zn(II) coordination polymer crystalline material 1, and the corresponding fluorescence emission spectrum was measured.

[0073] like Figure 7 As shown, with Cu 2+ With the increase of concentration, the fluorescence intensity in the supernatant gradually decreased.

[0074] like Figure 8 As shown, the fluorescence intensity of the obtained Zn(II) coordination polymer crystalline material 1 is similar to that of Cu 2+ The concentration showed a good linear relationship, R 2 =0.99101.

[0075] Anti-interference is one of the important factors in evaluating specific recognition. In reality, there are other heavy metal ions in water that interfere with fluorescence detection results, including Cd 2+ 、Lu 2+ 、Co 3+ 、Fe 2+ Cr 3+ 、Ag 2+ 、Ni 2+ 、Al 3+ 、Y 3+ like Figure 9 As shown, when Cu is added to the solution 2+ , Zn(II) coordination polymer crystalline materials show the same 2+ Strong sensitivity, can effectively monitor Cu in water 2+ .

[0076] The above description 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 variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A Zn(II) coordination polymer crystalline material, characterized in that: The single crystal molecular formula of the Zn(II) coordination polymer crystalline material is C 14 H 20 N2O 17 Zn2, the chemical formula of the Zn(II) coordination polymer crystalline material is {[Zn2(H2O)6(DODDA)]·4H2O} n The Zn(II) coordination polymer crystalline material is an orthorhombic crystal system with a space group of Imma. The unit cell parameters include a=21.3223(6) Å, b=26.1017(8) Å, c=7.2108(2) Å, α= 90.00°, β= 90.00° and γ=90.00°. In the chemical formula, DODDA 4- is deprotonated H4(DODDA), wherein H4(DODDA) is 1-(3,5-dicarboxyphenyl)-4-oxo-1,4-dihydropyridazine-3,5-dicarboxylic acid, and the structural formula of H4(DODDA) is: 。 2. A method for preparing the Zn(II) coordination polymer crystalline material according to claim 1, characterized in that: The following steps are involved: S1. Add H4(DODDA) and zinc salt to DMA to obtain a mixed solution, keep the solution at a constant temperature for sufficient reaction, and then allow the solution to stand to obtain a reaction product; S2. Cooling the reaction product obtained in S1 to crystallize, and washing, filtering and drying the crystallized product in sequence to obtain a Zn(II) coordination polymer crystalline material.

3. The preparation method according to claim 2, characterized in that The zinc salt in S1 is zinc nitrate hexahydrate, and the mass volume ratio of H4(DODDA), zinc salt and DMA is 0.1 mmol:0.1 mmol:2 mL.

4. The preparation method according to claim 2, characterized in that The temperature for the constant temperature full reaction in S1 is 80-95° C., the time for the constant temperature full reaction is 45-50 h, and the standing time is 12 h.

5. The preparation method according to claim 2, characterized in that The rinsing agent in S2 is deionized water, the filtration is reduced-pressure filtration, the drying temperature is 60° C., and the drying time is 2 to 4 hours.

6. An application of the Zn(II) coordination polymer crystalline material as claimed in claim 1, characterized in that: The Zn(II) coordination polymer crystalline material is used for selective and sensitive detection of Cu in aqueous solution. 2+ ion.

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