Lanthanide metal coordination polymers, methods of making and using the same

Abstract

This invention relates to the fields of fluorescence sensing technology and photocatalytic degradation of organic dyes, and particularly to a lanthanide coordination polymer, its preparation method, and its applications. This invention utilizes a one-pot hydrothermal reaction to prepare the lanthanide coordination polymer [Gd(piac)2(H2O)2]. n Or [Tb(piac)2(H2O)2] n The molecular formulas are C 22 H 17 N4O 10 Gd or C 22 H 17 N4O 10 Tb. This preparation method has advantages such as simple process, convenient operation, high yield, and good reproducibility. The terbium(III) coordination polymer prepared by this invention exhibits good fluorescence properties, particularly for Cu. 2+ Exhibiting high selectivity and high sensitivity, it can effectively detect Cu through fluorescence quenching. 2+ Meanwhile, gadolinium(III) coordination polymers have good photocatalytic degradation performance for organic dyes, and exhibit good photocatalytic degradation effects on organic dyes Rhodamine B and methyl orange.

Description

Technical Field

[0001] This invention relates to the fields of fluorescence sensing technology and photocatalytic degradation of organic dyes, and particularly to a lanthanide metal coordination polymer, its preparation method, and its application. Background Technology

[0002] With the development of industry, many metal ions are released through industrial wastewater, endangering people's health, especially Cu. 2+ The primary source of copper intake for humans is through daily diet. Copper ions can accumulate through the food chain and eventually enter the human body. Excessive intake of copper ions can cause harm to the body, such as kidney damage, liver necrosis, and nerve damage. Therefore, establishing effective methods for detecting copper in water is crucial. 2+ These methods are crucial for protecting ecosystems and human health.

[0003] Current detection technologies often suffer from drawbacks such as long processing times and expensive equipment. Fluorescence sensing, however, has been extensively studied due to its high sensitivity, ease of operation, rapid response, high selectivity, and low cost. Many coordination polymers for detecting heavy metal ions, such as Pb(II), Hg(II), Cr(II), Co(II), and Cu(II), have been developed. They can also detect small organic molecules like nitrobenzene, acetone, and chloroform. However, most reported probe molecules are based on transition metal complexes. Although lanthanide metal complexes possess unique advantages, such as narrow emission spectra, high optical stability, and biodegradability, their study is relatively limited due to the high coordination numbers of lanthanide ions. Therefore, the construction of fluorescent probes based on rare earth complexes remains a crucial research focus.

[0004] Similarly, the emission of organic dye pollutants poses another threat to ecosystems and human health. These dyes are persistent and highly toxic, making them difficult to degrade. Photocatalysis can be used to degrade these dyes, particularly using lanthanide-based coordination polymers as catalysts. Photocatalysts are activated by light, generating reactive oxygen species that can break down complex dye molecules into simpler, less harmful compounds. Lanthanide coordination polymers, due to their unique structure and electronic properties, enhance light absorption and reactive oxygen generation, showing considerable potential in photocatalysis. The integration of fluorescence sensing with photocatalytic systems enables a single material to both detect and degrade organic pollutants. This innovative strategy greatly promotes the development of sustainable water treatment technologies. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a lanthanide metal coordination polymer, its preparation method, and its applications, wherein the lanthanide metal refers to gadolinium(III) or terbium(III), and its coordination polymer is [Gd(piac)2(H2O)2], respectively. n Or [Tb(piac)2(H2O)2] n The two coordination polymers are isomorphic two-dimensional structures. The two coordination polymers form an eight-coordinate structure with gadolinium(III) or terbium(III) as the center, respectively. They form a one-dimensional ring chain structure through coordination and connection of the oxygen atoms of the ligand carboxyl groups. The ring chain structure is further connected by ligand bridging to form a two-dimensional structure.

[0006] To address the aforementioned technical problems, this invention provides a lanthanide metal coordination polymer, wherein the chemical formula of the lanthanide metal coordination polymer is [Gd(piac)2(H2O)2]. n Or [Tb(piac)2(H2O)2] n The monomeric formulas of the lanthanide metal coordination polymers are C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C2 ...1, C21, C2 22 H 17 N4O 10 Gd or C 22 H 17 N4O 10 Tb.

[0007] This invention provides a method for preparing the above-mentioned lanthanide metal coordination polymer, comprising the following steps:

[0008] S1. Dissolve 5-(1H-pyrazol-3-yl)isophthalic acid and lanthanide metal salt in deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH value of the mixed solution, and then carry out a hydrothermal reaction to obtain the reaction product.

[0009] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is then washed and dried to obtain the lanthanide metal coordination polymer.

[0010] According to the preparation method of lanthanide metal coordination polymer provided by the present invention, the lanthanide metal salt in S1 is Gd(NO3)3·6H2O or TbCl3·6H2O.

[0011] According to the preparation method of the lanthanide metal coordination polymer provided by the present invention, the molar ratio of 5-(1H-pyrazol-3-yl)isophthalic acid and lanthanide metal salt in S1 is 0.05-0.1 mmol: 0.1-0.15 mmol.

[0012] According to the preparation method of lanthanide metal coordination polymer provided by the present invention, the pH value of the mixed solution in S1 is 5 to 7.

[0013] According to the preparation method of lanthanide metal coordination polymer provided by the present invention, the temperature of the hydrothermal reaction in S1 is 180°C, the temperature rise rate is 5-10°C / h, the hydrothermal reaction is carried out in a sealed reaction vessel, and the hydrothermal reaction time is 3-5 days.

[0014] According to the preparation method of lanthanide metal coordination polymer provided by the present invention, the drying conditions in S2 are: constant temperature drying oven at 60°C for 3 hours.

[0015] The present invention also provides an application of the above-mentioned lanthanide metal coordination polymer, which can be applied to the fields of fluorescent ion detection and photocatalytic dye degradation.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The present invention uses a one-pot hydrothermal reaction to prepare lanthanide metal coordination polymers, the chemical formula of which is [Gd(piac)2(H2O)2]. n Or [Tb(piac)2(H2O)2] n Their molecular formulas are C 22 H 17 N4O 10 Gd or C 22 H 17 N4O 10 Tb. This preparation method has the advantages of simple process, convenient operation, high yield and good reproducibility.

[0018] (2) The lanthanide metal coordination polymer [Tb(piac)2(H2O)2] prepared in this invention n It exhibits good fluorescence properties and is effective against Cu. 2+ Exhibiting high selectivity and high sensitivity, it can effectively detect Cu through fluorescence quenching. 2+ Meanwhile, the lanthanide metal coordination polymer [Gd(piac)2(H2O)2] prepared by this invention... n It exhibits excellent photocatalytic performance and demonstrates good photocatalytic degradation effect on organic dyes RhB and MO. Attached Figure Description

[0019] Figure 1 This is a diagram of the coordination environment of terbium(III) in terbium(III) coordination polymers;

[0020] Figure 2 This is a one-dimensional structural diagram of a terbium(III) coordination polymer;

[0021] Figure 3 This is a two-dimensional structural diagram of a terbium(III) coordination polymer;

[0022] Figure 4 This is a diagram of the coordination environment of gadolinium(III) in gadolinium(III) coordination polymers;

[0023] Figure 5 This is a one-dimensional structural diagram of a gadolinium(III) coordination polymer;

[0024] Figure 6 Two-dimensional structure diagram of gadolinium(III) coordination polymers;

[0025] Figure 7 These are X-ray diffraction patterns of terbium(III) coordination polymers and gadolinium(III) coordination polymers.

[0026] Figure 8 These are emission spectra of terbium(III) coordination polymers in different ions;

[0027] Figure 9 This is a comparison chart of the strength of terbium(III) coordination polymers in different ions;

[0028] Figure 10 This is the absorption spectrum of gadolinium(III) coordination polymers for RhB and MO;

[0029] Figure 11 This is a graph showing the degradation rates of RhB and MO by gadolinium(III) coordination polymers. Detailed Implementation

[0030] Example 1

[0031] This embodiment provides a method for preparing lanthanide metal coordination polymers, the specific steps of which are as follows:

[0032] S1. Dissolve 0.05 mmol of the ligand 5-(1H-pyrazol-3-yl)isophthalic acid (H2piac) and 0.1 mmol of the metal salt Gd(NO3)3·6H2O in 10 mL of deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH of the mixed solution to 5. Then transfer the mixed solution to a high-pressure reactor. The temperature inside the high-pressure reactor is increased to 180℃ at a heating rate of 10℃ / h. The solvothermal reaction is carried out for 5 days to obtain the reaction product.

[0033] The structural formula of H2piac is:

[0034]

[0035] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a white crystalline powder. This powder is then dried in an oven at 60°C for 3 hours to obtain a lanthanide metal coordination polymer and a gadolinium(III) coordination polymer [Gd(piac)2(H2O)2]. n The yield was 37%.

[0036] Example 2

[0037] S1. Dissolve 0.1 mmol of the ligand 5-(1H-pyrazol-3-yl)isophthalic acid and 0.1 mmol of the metal salt Gd(NO3)3·6H2O in 10 mL of deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH of the mixed solution to 5.5. Then transfer the mixed solution to a high-pressure reactor. The temperature inside the high-pressure reactor is increased to 180℃ at a heating rate of 10℃ / h and carried out a solvothermal reaction for 3 days to obtain the reaction product.

[0038] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a white crystalline powder. This powder is then dried in an oven at 60°C for 3 hours to obtain a lanthanide metal coordination polymer and a gadolinium(III) coordination polymer [Gd(piac)2(H2O)2]. n The yield was 41.1%.

[0039] Example 3

[0040] This embodiment provides a method for preparing lanthanide metal coordination polymers, the specific steps of which are as follows:

[0041] S1. Dissolve 0.1 mmol of the ligand 5-(1H-pyrazol-3-yl)isophthalic acid and 0.1 mmol of the metal salt TbCl3·6H2O in 10 mL of deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH of the mixed solution to 6.3. Then transfer the mixed solution to a high-pressure reactor. The temperature inside the high-pressure reactor is increased to 180℃ at a heating rate of 10℃ / h and carried out a solvothermal reaction for 5 days to obtain the reaction product.

[0042] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a white crystalline powder. This powder is then dried in an oven at 60°C for 3 hours to obtain a lanthanide metal coordination polymer and a terbium(III) coordination polymer [Tb(piac)2(H2O)2]. n The yield was 75.6%.

[0043] Example 4

[0044] This embodiment provides a method for preparing lanthanide metal coordination polymers, the specific steps of which are as follows:

[0045] S1. Dissolve 0.1 mmol of the ligand 5-(1H-pyrazol-3-yl)isophthalic acid and 0.1 mmol of the metal salt TbCl3·6H2O in 10 mL of deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH of the mixed solution to 5.5. Then transfer the mixed solution to a high-pressure reactor. The temperature inside the high-pressure reactor is increased to 180℃ at a heating rate of 10℃ / h and carried out a solvothermal reaction for 4 days to obtain the reaction product.

[0046] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a white crystalline powder. This powder is then dried in an oven at 60°C for 3 hours to obtain a lanthanide metal coordination polymer and a terbium(III) coordination polymer [Tb(piac)2(H2O)2]. n The yield was 55.6%.

[0047] Example 5

[0048] This embodiment provides a method for preparing lanthanide metal coordination polymers, the specific steps of which are as follows:

[0049] S1. Dissolve 0.1 mmol of the ligand 5-(1H-pyrazol-3-yl)isophthalic acid and 0.15 mmol of the metal salt Gd(NO3)3·6H2O in 10 mL of deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH of the mixed solution to 6.3. Then transfer the mixed solution to a high-pressure reactor. The temperature inside the high-pressure reactor is increased to 180℃ at a heating rate of 10℃ / h and carried out a solvothermal reaction for 5 days to obtain the reaction product.

[0050] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a white crystalline powder. This powder is then dried in an oven at 60°C for 3 hours to obtain a lanthanide metal coordination polymer and a gadolinium(III) coordination polymer [Gd(piac)2(H2O)2]. n The yield was 71.4%.

[0051] Example 6

[0052] This comparative example provides a method for preparing lanthanide metal coordination polymers, the specific steps of which are as follows:

[0053] S1. Dissolve 0.1 mmol of the ligand 5-(1H-pyrazol-3-yl)isophthalic acid and 0.1 mmol of the metal salt Gd(NO3)3·6H2O in 10 mL of deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH of the mixed solution to 5.8. Then transfer the mixed solution to a high-pressure reactor. The temperature inside the high-pressure reactor is increased to 180℃ at a heating rate of 10℃ / h and carried out a solvothermal reaction for 5 days to obtain the reaction product.

[0054] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a white crystalline powder. This powder is then dried in an oven at 60°C for 3 hours to obtain a lanthanide metal coordination polymer and a gadolinium(III) coordination polymer [Gd(piac)2(H2O)2]. n The yield was 54.8%.

[0055] Example 7

[0056] This comparative example provides a method for preparing lanthanide metal coordination polymers, the specific steps of which are as follows:

[0057] S1. Dissolve 0.1 mmol of the ligand 5-(1H-pyrazol-3-yl)isophthalic acid and 0.1 mmol of the metal salt TbCl3·6H2O in 10 mL of deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH of the mixed solution to 5.8. Then transfer the mixed solution to a high-pressure reactor. The temperature inside the high-pressure reactor is increased to 180℃ at a heating rate of 10℃ / h and carried out a solvothermal reaction for 5 days to obtain the reaction product.

[0058] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a white crystalline powder. This powder is then dried in an oven at 60°C for 3 hours to obtain a lanthanide metal coordination polymer and a terbium(III) coordination polymer [Tb(piac)2(H2O)2]. n The yield was 51.6%.

[0059] Example 8

[0060] This comparative example provides a method for preparing lanthanide metal coordination polymers, the specific steps of which are as follows:

[0061] S1. Dissolve 0.1 mmol of the ligand 5-(1H-pyrazol-3-yl)isophthalic acid and 0.1 mmol of the metal salt Gd(NO3)3·6H2O in 10 mL of deionized water to obtain a mixed solution. Add NaOH solution to adjust the pH of the mixed solution to 7.0. Then transfer the mixed solution to a high-pressure reactor. The temperature inside the high-pressure reactor is increased to 180℃ at a heating rate of 10℃ / h and carried out a solvothermal reaction for 5 days to obtain the reaction product.

[0062] S2. After the reaction product obtained in S1 is allowed to cool naturally and crystallize, it is washed with anhydrous ethanol and filtered under reduced pressure to obtain a white crystalline powder. This powder is then dried in an oven at 60°C for 3 hours to obtain a lanthanide metal coordination polymer and a gadolinium(III) coordination polymer [Gd(piac)2(H2O)2]. n The yield was 40.9%.

[0063] Example 9

[0064] The terbium(III) coordination polymers prepared in Example 3 and the gadolinium(III) coordination polymers prepared in Example 5 were further characterized as follows:

[0065] (1) Determination of the crystal structure of lanthanide metal coordination polymers

[0066] Single crystals of coordination polymers with clean, smooth surfaces, no concave areas, and no cracks were selected and analyzed using a BRDUKERSMARTAPEX-ⅡCCDX-X single crystal diffractometer at a temperature of 293(2)K, with graphite monochromatic Mo-Kα (wavelength 10 ... ) rays, with Diffraction data were collected using a scanning method. All data were corrected for empirical absorption, and the crystal structure was solved using a direct method. The anisotropy parameters and coordinates of all non-hydrogen atoms were corrected using the least squares method. F2 was refined using the SHELXTL-97 program, and the coordinates of hydrogen atoms were obtained by theoretical calculations.

[0067] Detailed crystal measurement data are shown in Tables 1 and 2; important bond lengths and bond angles are shown in Tables 3 and 4; and the crystal structure is shown in Table 4. Figures 1-6 .

[0068] Table 1. Key crystallographic data for terbium(III) coordination polymerization.

[0069]

[0070]

[0071] Where R1=∑(||Fo|-|Fc||) / ∑|Fo|, wR2=[∑w(Fo ... 2 -|Fc2 ) 2 / ∑w(Fo) 2 ] 1 / 2 ;

[0072] Table 2. Key crystallographic data of gadolinium(III) coordination polymers

[0073]

[0074]

[0075] Table 3 Important bond lengths of terbium(III) coordination polymers Bond angle (°)

[0076]

[0077]

[0078] Table 4 Important bond lengths of gadolinium(III) coordination polymers Bond angle (°)

[0079]

[0080]

[0081] In Table 1, a, b, and c represent the edge lengths of the crystal along the three crystal axes, respectively; α, β, and γ represent the angles between axes a and b, a and c, and b and c, respectively; Z is the number of molecules in a unit cell; the diffraction index range of the restriction factor is (h, k, l); F(000) is the number of electrons in a unit cell; Θ is the range of Θ angles for data collection; FinalRindices[I>2σ(I)] is the residual factor R value for observable diffraction points; R is the unweighted consistency factor; R1 and wR2 are both weighted consistency factors.

[0082] In Table 3, Tb1 in the first row refers to Tb atom 1 in terbium(III) coordination polymer single crystal, O5 refers to O atom 5 in terbium(III) coordination polymer single crystal, and Tb1-O5 represents the bond length between Tb atom 1 and O atom 5, which is 2.280±2, where 2 is the standard deviation.

[0083] O5-Tb1-O2 represents the bond angle between O atom 5, Tb atom 1 and O atom 2, which is 129.66±9.

[0084] The same logic applies to the other data in the table.

[0085] The two complexes are isomorphic two-dimensional structures. The terbium (III) coordination polymer and the gadolinium (III) coordination polymer form an eight-coordinate structure with terbium (III) and gadolinium (III) as the center, respectively. They form a one-dimensional ring chain structure through coordination and connection of the carboxyl oxygen atoms of the ligands. The ring chain structure is further connected by ligands to form a two-dimensional structure.

[0086] (2) Characterization of phase purity of lanthanide metal coordination polymers

[0087] The powders of terbium(III) coordination polymers and gadolinium(III) coordination polymers were characterized by XRD using a Bruker / D8 Advance instrument. The characterization results are shown in [Figure number missing]. Figure 7 This demonstrates that it possesses reliable phase purity, ensuring its application in fluorescence sensing and photocatalytic degradation of organic dyes.

[0088] Example 10

[0089] Weigh 2 mg of the terbium(III) coordination polymer prepared in Example 3 by grinding, and immerse it in an equal volume of DMF solution containing different ions (M = NaNO3, KNO3, LiNO3, Hg(NO3)2, Cu(NO3)2, Pb(NO3)2, Zn(NO3)2, Cd(NO3)2, Mn(NO3)2 and Co(NO3)2) at a concentration of 1 mol / L. After sonication and standing, the clear supernatant was used for luminescence studies at room temperature.

[0090] The emission intensity of the complex under different ions was measured at an excitation wavelength of 345 nm. It can be seen that when Cu... 2+ When present, the luminescence intensity of the complex decreases significantly, indicating that this terbium(III) complex affects Cu. 2+ There is a significant fluorescence quenching phenomenon, therefore Cu can be effectively detected through fluorescence quenching. 2+ The result is as follows Figure 8 and Figure 9 As shown.

[0091] Example 11

[0092] 15 mg of the gadolinium(III) coordination polymer prepared in Example 5 was ground and added to a 50 mL reactor containing 30 mg / L rhodamine B (Rh B) and methyl orange solution (MO). After sonication, the mixture was placed in a dark reaction chamber for 30 min, followed by a light reaction for 120 min.

[0093] Take 5 mL of the reaction solution every 15 minutes and measure its absorbance using a UV-Vis analyzer. The results are as follows: Figure 10 As shown, the absorbance of Rhodamine B and methyl orange decreases significantly in the presence of gadolinium(III) coordination polymers.

[0094] This phenomenon indicates that gadolinium(III) coordination polymers are excellent photocatalysts, capable of effectively degrading rhodamine B and methyl orange, as shown in the results. Figure 11 As shown.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A lanthanide metal coordination polymer, characterized in that, The chemical formula of the lanthanide metal coordination polymer is: [Gd(piac)2(H2O)2] n or [Tb(piac)2(H2O)2] n , wherein the ligand piac 2- is deprotonated H2piac, the H2piac is 5-(1H-pyrazol-3-yl)isophthalic acid, and the monomolecular formula of the lanthanide metal coordination polymer is C 22 H 17 N4O 10 Gd or C 22 H 17 N4O 10 Tb, respectively.

2. A method for producing the lanthanide coordination polymer according to claim 1, characterized by, The method comprises the following steps: S1, dissolving 5-(1H-pyrazol-3-yl) isophthalic acid and lanthanide metal salt in deionized water to obtain a mixed solution, adding NaOH solution to adjust the pH value of the mixed solution, and then obtaining a reaction product through a hydrothermal reaction; S2, naturally cooling and crystallizing the reaction product obtained in S1, and then washing and drying to obtain a lanthanide metal coordination polymer.

3. The method of claim 2, wherein the lanthanide metal coordination polymer is prepared by the reaction of a lanthanide metal salt and a ligand in a solvent. The lanthanide metal salt in S1 is Gd(NO3)3·6H2O or TbCl3·6H2O.

4. The method of claim 2, wherein the lanthanide metal coordination polymer is prepared by the reaction of a lanthanide metal salt and a ligand in a solvent. The molar ratio of 5-(1H-pyrazol-3-yl) isophthalic acid to lanthanide metal salt in S1 is 0.05-0.1 mmol:0.1-0.15 mmol.

5. The method of claim 2, wherein the lanthanide metal coordination polymer is prepared by the reaction of a lanthanide metal salt and a ligand in a solvent. The pH value of the mixed solution in S1 is 5-7.

6. The method of claim 5, wherein the lanthanide metal coordination polymer is prepared by the reaction of a lanthanide metal salt with a ligand in a solvent. The temperature of the hydrothermal reaction in S1 is 180℃, the temperature rising rate in the hydrothermal reaction is 5-10℃ / h, the hydrothermal reaction is carried out in a sealed reaction kettle, and the time of the hydrothermal reaction is 3-5d.

7. The method for preparing the lanthanide metal coordination polymer according to claim 2, characterized in that, The drying condition in S2 is that the drying is carried out in a constant temperature drying box at 60℃ for 3h.

8. Use of a lanthanide metal-organic framework according to any one of claims 1 to 7, characterized in that, The lanthanide metal coordination polymer can be applied to the fields of fluorescent ion detection and photocatalytic degradation of organic dyes.

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