A three-dimensional Tb-MOF compound, a preparation method and application thereof

Abstract

This invention discloses a three-dimensional Tb-MOF compound, its preparation method, and its applications. The chemical formula of the Tb-MOF is {[H2N(CH3)2](H3O)[Tb(btec)(HCOO)(H2O)3]}. n btec is the ligand pyromellitic acid. The preparation method includes the following steps: reacting terbium salt, ligands N,N-bis(3,5-dicarboxylic acid phenyl)pyromellitic diimide and N,N-dimethylformamide, and dilute hydrochloric acid at 120-150℃ for 24-72 h; after the reaction, naturally cooling to room temperature, filtering, washing, and drying to obtain the three-dimensional Tb-MOF compound. The three-dimensional Tb-MOF compound can be used to detect 4-hydroxybenzaldehyde and metal ions Al. 3+ .

Description

Technical Field

[0001] This invention relates to metal-organic framework-based luminescent materials, specifically to a three-dimensional Tb-MOF compound, its preparation method, and its applications. Background Technology

[0002] With the rapid development of science and technology, people's living standards have greatly improved, but environmental pollution, food poisoning, and ecological damage have also followed. Aluminum ions are a common metal ion in daily life, but levels exceeding normal limits can harm human health. Aluminum's toxicity is relatively slow and not easily detected in the early stages; only when it accumulates to a certain level will metabolic disorders and toxic reactions occur. Studies have shown that excessive Al3+ can trigger neurodegenerative diseases and metabolic disorders, and is significantly associated with the pathogenesis of various malignant tumors.

[0003] On the other hand, 4-hydroxybenzaldehyde is an important intermediate in the pharmaceutical and fragrance industries, playing a significant role in their synthesis. However, 4-hydroxybenzaldehyde is a common toxic gas found in interior decoration materials, posing a significant health risk, potentially causing olfactory, gustatory, and digestive system disorders, and even cancer. Due to its strong carcinogenicity and multi-organ toxicity, it is classified as a Group II hazardous chemical by the World Health Organization. Therefore, developing a rapid-response, highly efficient, and simple-to-operate method for reacting 4-hydroxybenzaldehyde with metal ions (Al) is crucial. 3+ The detection methods have become a technical challenge that urgently needs to be overcome in the fields of environmental monitoring and health protection.

[0004] Currently, it is widely used in 4-hydroxybenzaldehyde and metal ions Al 3+ Detection techniques include high-performance liquid chromatography (HPLC), inductively coupled plasma (ICP), electrochemical analysis, and atomic absorption spectrometry (AAS); however, their application is limited due to drawbacks such as complex operation, high cost, and poor detection results. Of particular note, luminescent metal-organic frameworks (LMOFs) have been widely used in the detection of ions, volatile organic compounds (VOCs), antibiotics, and biomarkers due to their optical tunability and fluorescence diversity. Lanthanide metal-organic frameworks (Ln-MOFs), in particular, possess excellent luminescent characteristics such as strong emission peaks, long emission lifetimes, and high luminescence efficiency, making them increasingly favored in the field of fluorescence sensors.

[0005] However, existing technologies suffer from two major shortcomings: First, LMOF-based fluorescent probes are currently lacking in the detection of 4-hydroxybenzaldehyde, with existing research primarily focusing on traditional volatile organic compounds such as formaldehyde and nitro compounds. Second, the reported LMOF-based fluorescent probes for Al3+ detection generally exhibit fluorescence quenching response modes, making them susceptible to false positives due to environmental interference, while reports on ratiometric sensors based on dual emission peak self-calibration are scarce. This technological bottleneck severely restricts the development of rapid on-site detection equipment and makes it even more difficult to meet the urgent need for simultaneous monitoring of multiple pollutants in complex matrices. Therefore, developing LMOF-based materials for the detection of 4-hydroxybenzaldehyde and metal ions Al3+ is crucial. 3+ Multifunctional materials are of great significance. Summary of the Invention

[0006] The purpose of this invention is to provide a three-dimensional Tb-MOF compound, its preparation method, and its applications, which can efficiently and selectively recognize 4-hydroxybenzaldehyde and metal ions Al. 3+ .

[0007] In one aspect of the invention, a three-dimensional Tb-MOF compound is proposed. According to an embodiment of the invention, the chemical formula of the compound is {[H2N(CH3)2](H3O)[Tb(btec)(HCOO)(H2O)3]}. n btec is the ligand pyromellitic acid.

[0008] In another aspect of the present invention, a method for preparing a three-dimensional Tb-MOF compound is provided. According to an embodiment of the present invention, the method includes the following steps: reacting a terbium salt, the ligand N,N-bis(3,5-dicarboxylic acid phenyl)pyromellitictetracarboxydiimide and N,N-dimethylformamide, and dilute hydrochloric acid at 120-150°C for 24-72 h; after the reaction is completed, naturally cooling to room temperature; filtering, washing, and drying to obtain the three-dimensional Tb-MOF compound.

[0009] In addition, the method for preparing a three-dimensional Tb-MOF compound according to the above embodiments of the present invention may also have the following additional technical features:

[0010] In some embodiments of the present invention, the terbium salt is at least one of terbium nitrate and terbium chloride.

[0011] In some embodiments of the present invention, the molar ratio of the terbium salt, ligand N,N-bis(3,5-dicarboxylic acid phenyl)pyromellitic diimide, and N,N-dimethylformamide is (1.5-2.5):1:(520-780).

[0012] In some embodiments of the present invention, the concentration of the dilute hydrochloric acid is 0.5 to 1.5 mol / L, and the molar ratio of dilute hydrochloric acid to terbium salt is 1:(15 to 40).

[0013] In another aspect, the present invention provides a fluorescent detection material. According to an embodiment of the invention, the material comprises the aforementioned three-dimensional Tb-MOF compound, and the fluorescent detection material is used to detect 4-hydroxybenzaldehyde or metal ions Al. 3+ .

[0014] In another aspect of the present invention, a fluorescence detection method is proposed. According to an embodiment of the present invention, the method includes the following steps: dispersing the three-dimensional Tb-MOF compound crystalline material in an N,N-dimethylformamide solution to obtain a Tb-MOF suspension; adding a solution containing the analyte to the Tb-MOF suspension and shaking well; waiting 30-240 s; and collecting the fluorescence emission spectrum of the mixture using a fluorescence spectrometer. This method is used to detect 4-hydroxybenzaldehyde or metal ions (Al). 3+ .

[0015] In addition, the fluorescence detection method according to the above embodiments of the present invention may also have the following additional technical features:

[0016] In some embodiments of the present invention, when the analyte is 4-hydroxybenzaldehyde, the ratio of fluorescence intensity at 543 nm before and after the addition of the analyte is calculated to determine the concentration of 4-hydroxybenzaldehyde; when the analyte is a metal ion Al... 3+ Then, calculate the ratio of fluorescence intensity at 543nm to 362nm to determine Al. 3+ The concentration of Al in the solution containing the analyte 3+ The concentration of the analyte is 0-1.38 mmol / L; the concentration of 4-hydroxybenzaldehyde in the solution containing the analyte is 0-1.60 mmol / L.

[0017] In some embodiments of the present invention, the concentration of the Tb-MOF suspension is 0.5-1.0 mg / mL.

[0018] In another aspect of the invention, a luminescent material is proposed. An embodiment of the invention includes the aforementioned three-dimensional Tb-MOF compound.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1) The three-dimensional Tb-MOF compound prepared by this invention has excellent luminescence characteristics such as strong emission peak, long luminescence lifetime and high luminescence efficiency.

[0021] 2) This invention proposes a fluorescent detection material, which is equivalent to constructing a quenching fluorescent sensor for the detection of 4-hydroxybenzaldehyde and a material for detecting metal ions (Al). 3+ A dual-emission ratiometric fluorescence sensor was used for detection. When 4-hydroxybenzaldehyde was added to the Tb-MOF suspension, the fluorescence of Tb-MOF at 543 nm was completely quenched, with a quenching efficiency as high as 95.8%. When metal ions Al were added... 3+ At this time, the fluorescence intensity of the Tb-MOF suspension decreased at 543 nm, while the fluorescence intensity increased at 362 nm. This indicates that the three-dimensional Tb-MOF synthesized by this method is effective in the reaction of 4-hydroxybenzaldehyde and metal ions Al. 3+ It has good application potential in the detection of [substances / materials]. Attached Figure Description

[0022] Figure 1 The Tb in the three-dimensional Tb-MOF compound in Example 2 of this invention 3+ The coordination environment of the ion and the coordination mode of the ligand btec (a), the single-cap tetragonal antiprism structure of Tb1 (b) and the binuclear structure of Tb-MOF (c);

[0023] Figure 2 These are the one-dimensional chain structure (a) and three-dimensional supramolecular network structure (b) of the Tb-MOF compound in Example 2 of this invention;

[0024] Figure 3 The fluorescence spectra (a) of the three-dimensional Tb-MOF compound in Application Example 2 of this invention in response to different concentrations of 4-hydroxybenzaldehyde and the detection calibration curve (b) of 4-hydroxybenzaldehyde are shown.

[0025] Figure 4 This is a fluorescence detection bar chart of the three-dimensional Tb-MOF compound against 4-hydroxybenzaldehyde under the interference of other aldehyde components in Application Example 2 of this invention;

[0026] Figure 5 This invention applies the three-dimensional Tb-MOF compound in Example 3 to different concentrations of Al. 3+ Fluorescence spectrum of the response (a) and Al 3+ The detection calibration curve (b);

[0027] Figure 6 This is the solid-state fluorescence spectrum of the three-dimensional Tb-MOF compound in Application Example 4 of this invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] A three-dimensional Tb-MOF compound with the chemical formula {[H2N(CH3)2](H3O)[Tb(btec)(HCOO)(H2O)3]} n btec is the ligand pyromellitic acid, which is produced by the decomposition of the reactant ligand N,N-bis(3,5-dicarboxylic acid phenyl)pyromellitic diimide during the synthesis reaction. The three-dimensional Tb-MOF compound belongs to the orthorhombic crystal system and Cmmm space group. Its unit cell parameters are... β = 90°

[0031] Example 2

[0032] A method for preparing a three-dimensional Tb-MOF compound includes the following steps:

[0033] Terbium nitrate hexahydrate (90.6 mg, 0.2 mmol) and N,N-bis(3,5-dicarboxylic acid phenyl)pyromellitic diimide (54.4 mg, 0.1 mmol) were added to a 15 mL high-pressure reactor. Then, 5 mL of N,N-dimethylformamide (DMF) and 5 mL of 1 M HCl were added sequentially. The mixture was heated to 130 °C and reacted for 72 h. After cooling to room temperature, the mixture was filtered, washed three times with DMF, and dried at room temperature to obtain colorless flaky crystals, which are the three-dimensional Tb-MOF compound.

[0034] The determination was based on the single-crystal structure of a three-dimensional Tb-MOF compound, and the procedure is as follows:

[0035] A Tb-MOF single crystal with dimensions of 0.12 × 0.14 × 0.20 mm was selected and tested using a Bruker SMART APEX CCD X-ray single crystal diffractometer to collect single crystal data. Data analysis and optimization were performed using the Shelxl-2018 program. The crystal structure was solved using the direct method, and all non-hydrogen coordinates and anisotropic thermal parameters were corrected using the full matrix least squares method. The geometric positions of hydrogen atoms on carbon are consistent with the theoretical cycling model. Hydrogen atoms on coordinated water were determined by difference Fourier spectrum analysis. The structure contained highly disordered solvent molecules, which were removed using the SQUEEZE program in PLATON. The final molecular formula was obtained by combining crystal structure analysis with elemental analysis and thermogravimetric analysis. Table 1 summarizes the crystallographic data and structural refinement parameters of the Tb-MOF compound.

[0036] Table 1. Crystal structure data and refinement parameters of a three-dimensional Tb-MOF compound.

[0037]

[0038]

[0039] R1=∑||Fo|-|Fcs|| / ∑|Fo|wR2=∑[w(Fo 2 -Fc 2 ) 2 ] / ∑[w(Fo 2 ) 2 ] 1 / 2

[0040] Crystal structure such as Figure 1 and 2 As shown, Figure 1 (a) is a schematic diagram of the structure of the compound Tb-MOF, where Tb1 is coordinated with nine O atoms to form a single-capped tetragonal antiprism structure. Figure 1 (b)). Among them, O1 and O2, O1 i and O2 i The two ligands, btec, have carboxyl oxygen atoms, O6 and O6. i O7 originates from three O atoms in coordinated water, O5 and O5 i The O atoms on the two formic acid molecules; the four carboxyl O atoms on the two btec molecules (O1, O1) i O2, O2 i It occupies the four vertices of the base of the single-cap square antiprism structure; the two O atoms on the two H2O atoms (O6, O6) i ) and the two O atoms on the two formic acid atoms (O5, O5) i) Forms another plane. The ligand btec has only one coordination mode in Tb-MOF, bidentate chelation; the carboxyl group on the ligand has only one coordination mode, chelate coordination. The Tb-O bond length ranges from 2.336 (2)- The bond angles of O-Tb-O range from 50.65°(8) to 153.00°(12), similar to those reported in the literature. In the structure of Tb-MOF, Tb1 chelates with four carboxyl groups from two different ligands btec to form a binuclear structure, such as... Figure 1 (c) shows that this binuclear structure is connected by two formic acid molecules to form a one-dimensional chain structure, such as... Figure 2 (a) One-dimensional chain structures are then linked together by hydrogen bonds between uncoordinated carboxyl groups and coordinated water on the btec structure to form a three-dimensional supramolecular network structure, such as... Figure 2 (b)

[0041] Example 3

[0042] A method for preparing a three-dimensional Tb-MOF compound includes the following steps:

[0043] Terbium chloride hexahydrate (74.7 mg, 0.2 mmol) and N,N-bis(3,5-dicarboxylic acid phenyl)pyromellitic diimide (54.4 mg, 0.1 mmol) were added to a 15 mL high-pressure reactor, followed by the addition of 4.5 mL of N,N-dimethylformamide (DMF) and 5 mL of 1 M HCl. The mixture was heated to 120 °C and reacted for 48 h. After cooling to room temperature, the mixture was filtered, washed three times with DMF, and dried at room temperature to obtain colorless flaky crystals, which are the three-dimensional Tb-MOF compound.

[0044] Application Example 1

[0045] A fluorescent detection material, using the Tb-MOF compound prepared in Example 2 as the detection material, is used to detect 4-hydroxybenzaldehyde or metal ions Al. 3+ .

[0046] Application Example 2

[0047] A fluorescence detection method for 4-hydroxybenzaldehyde includes the following steps:

[0048] (1) Take 3 mg of the three-dimensional Tb-MOF compound prepared in Example 2, grind it into powder, and disperse it in 5 mL of DMF by ultrasonication. Sonicate for 30 min to form a suspension and prepare a 0.6 mg / mL Tb-MOF fluorescent probe solution.

[0049] (2) Take 1.5 mL of 0.6 mg / mL Tb-MOF fluorescent probe solution and gradually add 0.01 M DMF solution of 4-hydroxybenzaldehyde to it. That is, add different microliters of 0.01 M DMF solution of 4-hydroxybenzaldehyde in batches. After each addition, measure the fluorescence spectrum to obtain all the spectra, such as... Figure 3 As shown in (a), calculate the ratio of fluorescence intensity at 543 nm before and after adding the test solution to determine the concentration of 4-hydroxybenzaldehyde.

[0050] like Figure 3 As shown, with the gradual addition of 4-hydroxybenzaldehyde, the fluorescence intensity of Tb-MOF at 543 nm gradually decreased until it was almost completely quenched; when the concentration of 4-hydroxybenzaldehyde was in the range of 0-0.1 mM, its concentration was linearly correlated with I0 / I, K = 29.44 × 10⁻⁶. 3 M -1 The detection limit was 0.79 μM. When the concentration of 4-hydroxybenzaldehyde was in the range of 0.1-0.7 mM, its concentration still showed a linear correlation with I0 / I, K = 97.10 × 10⁻⁶. 3 M -1 This indicates that the concentration of 4-hydroxybenzaldehyde can be determined over a relatively wide range.

[0051] The detection of 4-hydroxybenzaldehyde by three-dimensional Tb-MOF compounds under interference from other aldehydes was investigated. Figure 4 As shown, in the presence of other similar aldehyde aromatic compounds (3-hydroxybenzaldehyde, 3-carboxybenzaldehyde, 4-carboxybenzaldehyde, or 3-methylbenzaldehyde), 4-hydroxybenzaldehyde can still quench the fluorescence of compound Tb-MOF, indicating its excellent anti-interference ability. This demonstrates that Tb-MOF is a superior sensor for recognizing 4-hydroxybenzaldehyde.

[0052] Application Example 3

[0053] A kind of Al 3+ The fluorescence detection method includes the following steps:

[0054] (1) Take 3 mg of the three-dimensional Tb-MOF compound prepared in Example 2, grind it into powder, and disperse it in 5 mL of DMF by ultrasonication. Sonicate for 30 min to form a suspension and prepare a 0.6 mg / mL Tb-MOF fluorescent probe solution.

[0055] (2) Take 1.5 mL of 0.6 mg / mL Tb-MOF fluorescent probe solution and gradually add 0.01 M Al to it. 3+ A DMF solution containing ions, i.e., 0.01M Al added in batches at different microliter volumes. 3+For each addition of ions to a DMF solution, a fluorescence spectrum is measured to obtain all the spectra, such as... Figure 5 As shown in (a). Calculate the ratio of fluorescence intensity at 543 nm to 362 nm to determine the metal ion Al. 3+ The concentration.

[0056] like Figure 5 As shown, with the increase of Al in the Tb-MOF fluorescent probe solution 3+ As the ion concentration gradually increases, the intensity of Tb-MOF at 543 nm gradually decreases, while the fluorescence intensity at 362 nm gradually increases; and in the concentration range of 0-0.3 mM, Al... 3+ Concentration and I 543 / I 362 The relationship is linear, and the linear regression equation is I. 543 / I 362 = -22.43 × [Al] 3+ The detection limit was +16.16, and the limit of detection was 0.67 μM. This indicates that the Tb-MOF fluorescent probe prepared in this invention is effective against Al. 3+ Ion detection has high sensitivity.

[0057] Application Example 4

[0058] A luminescent material comprising the three-dimensional Tb-MOF compound prepared in Example 2.

[0059] The three-dimensional Tb-MOF compound crystal sample prepared in Example 2 was thoroughly ground and subjected to solid-state luminescence testing at room temperature. Figure 6 As shown, when the excitation wavelength is set to 290 nm, the compound Tb-MOF exhibits Tb 3+ The four characteristic emission peaks are at 488 nm ( 5 D4→ 7 F6), 543nm 5 D4→ 7 F5), 584nm 5 D4→ 7 F4) and 620nm 5 D4→ 7 F6), of which 543nm ( 5 D4→ 7 The emission intensity is strongest at F5, therefore Tb-MOF exhibits characteristic green luminescence under ultraviolet light irradiation. This suggests its potential applications in luminescent materials.

[0060] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a three-dimensional Tb-MOF compound, characterized in that, The reaction includes the following steps: reacting terbium salt, ligand N,N-bis(3,5-dicarboxylic acid phenyl)pyromellitic diimide and N,N-dimethylformamide, and dilute hydrochloric acid at 120~150 °C for 24~72 h, and after the reaction is completed, naturally cooling to room temperature, filtering, washing, and drying to obtain the three-dimensional Tb-MOF compound, wherein the molar ratio of terbium salt, ligand N,N-bis(3,5-dicarboxylic acid phenyl)pyromellitic diimide to N,N-dimethylformamide is (1.5~2.5):1:(520~780).

2. The method for preparing a three-dimensional Tb-MOF compound according to claim 1, characterized in that: The terbium salt is at least one of terbium nitrate and terbium chloride.

3. The method for preparing a three-dimensional Tb-MOF compound according to claim 1, characterized in that: The concentration of the dilute hydrochloric acid is 0.5~1.5 mol / L, and the molar ratio of dilute hydrochloric acid to terbium salt is 1:(15~40).

4. A three-dimensional Tb-MOF compound, characterized in that: The three-dimensional Tb-MOF compound is prepared by the preparation method according to any one of claims 1-3, and the chemical formula of the compound is {[H2N(CH3)2](H3O)[Tb(btec)(HCOO)(H2O)3]}. n Where btec is deprotonated pyromellitic acid.

5. A fluorescent detection material, characterized in that: The material comprises the three-dimensional Tb-MOF compound of claim 4, and the fluorescent detection material is used to detect 4-hydroxybenzaldehyde or metal ions Al. 3+ .

6. A fluorescence detection method, characterized in that, The method includes the following steps: dispersing the three-dimensional Tb-MOF compound crystalline material of claim 4 in an N,N-dimethylformamide solution to obtain a Tb-MOF suspension; adding a solution containing the analyte to the Tb-MOF suspension and shaking well; waiting 30-240 s; and collecting the fluorescence emission spectrum of the mixture using a fluorescence spectrometer. This method is used to detect 4-hydroxybenzaldehyde or metal ions Al. 3+ .

7. The fluorescence detection method according to claim 6, characterized in that: When the analyte is 4-hydroxybenzaldehyde, the ratio of fluorescence intensity at 543 nm before and after the addition of the analyte is calculated to determine the concentration of 4-hydroxybenzaldehyde; when the analyte is a metal ion Al... 3+ Then, calculate the ratio of fluorescence intensity at 543 nm to 362 nm to determine Al. 3+ The concentration of Al in the solution containing the analyte 3+ The concentration of the analyte is 0-1.38 mmol / L; the concentration of 4-hydroxybenzaldehyde in the solution containing the analyte is 0-1.60 mmol / L.

8. The fluorescence detection method according to claim 7, characterized in that: The concentration of the Tb-MOF suspension is 0.5-1.0 mg / mL.

9. A luminescent material, characterized in that: Including the three-dimensional Tb-MOF compound of claim 4.

Images