Preparation method and application of cadmium-cobalt bimetallic organic framework
By preparing the cadmium-cobalt bimetallic organic framework CdCoBTCHx, the gap in the synthesis of cadmium-cobalt bimetallic organic frameworks was solved, and highly selective identification and visual detection of sulfur-containing amino acids were achieved, which has important applications in biomedicine and food detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HANSHAN NORMAL UNIV
- Filing Date
- 2025-01-12
- Publication Date
- 2026-05-12
AI Technical Summary
现有技术中镉钴双金属有机框架的合成存在空白，且其在含硫氨基酸识别上未得到有效应用。
A cadmium-cobalt bimetallic organic framework, CdCoBTCHx, was prepared by reacting Cd(NO3)2·4H2O, Co(NO3)2·6H2O, Hx, and H3BTC in a DMF solvent in a ratio of 2:1:2:1, adjusting the pH, and then heating at a constant temperature. The structure and purity of the framework were determined by property analysis.
The prepared cadmium-cobalt bimetallic organic framework CdCoBTCHx can significantly enhance the detection signals for cysteine and methionine, exhibiting good selectivity and visualization effects, and is suitable for biomedical and food detection.
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Figure CN120059205B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of bimetallic organic framework synthesis, in particular to a preparation method and application of a novel cadmium-cobalt bimetallic organic framework. BACKGROUND
[0002] Sulfur-containing amino acids play a crucial role in various metabolic processes, and are also a class of amino acids that have a greater impact on food flavor during heat treatment. As basic components of polypeptides and proteins, they are also biomarkers for predicting disease risk.
[0003] Metal-organic frameworks (MOFs) are a new type of porous crystalline material developed in the 1990s, which are usually formed by self-assembly of transition metal ions and multidentate organic ligands containing oxygen, nitrogen, etc. Mixed metal MOF materials generally refer to MOFs containing two or more different metal ions. Since the inorganic metal sites of single-metal MOFs are limited and relatively single, the introduction of other metal systems can increase the types of metal sites and make the arrangement more diverse. For example, ZnCo-ZIF-8 is synthesized by incorporating Co into ZIF-8, and a side-heating type gas sensor can be prepared by calcining it at 600 DEG C, which shows good selectivity in acetone detection. Heterovalent bimetallic MOF materials are relatively rare, such as the CPM-200 series, which is formed by matching trivalent In 3+ , Ga 3+ and divalent Mg 2+ , Mn 2+ and other metals, which exhibits excellent selective adsorption capacity for CO2.
[0004] However, due to the different coordination rates and coordination modes of different metal ions under the same conditions, the self-assembly and control of the final product of bimetallic MOFs still have great challenges. At present, there is a blank in the synthesis of cadmium-cobalt bimetallic organic frameworks, and cadmium-cobalt bimetallic organic frameworks have good effects on the recognition of sulfur-containing amino acids. SUMMARY
[0005] To solve the above problems, the application provides a preparation method and application of a novel cadmium-cobalt bimetallic organic framework, which is realized by the following technical scheme.
[0006] A preparation method of a novel cadmium-cobalt bimetallic organic framework, characterized in that it comprises the following steps:
[0007] S1, synthesis of cadmium-cobalt bimetallic organic framework;
[0008] Cd(NO3)2·4H2O, Co(NO3)2·6H2O, Hx, and H3BTC were placed in DMF solvent in a ratio of 2:1:2:1. After adjusting the pH with HNO3, the mixture was sealed in a polytetrafluoroethylene high-pressure reactor and heated at a constant temperature. Then, it was cooled to room temperature, filtered, and washed to obtain light purple crystals of CdCoBTCHx.
[0009] Where Hx is 6-hydroxypurine; H3BTC is 1,3,5-pyromellitic tricarboxylic acid; DMF solvent is N,N-dimethylformamide solvent; CdCoBTCHx is cadmium cobalt bimetallic organic framework;
[0010] Property analysis of S2,CdCoBTCHx crystals.
[0011] Preferably, in step S1, the concentration of HNO3 is 1 mol / L; the constant temperature heating temperature is 140℃ and the time is 72 h; after constant temperature heating, the temperature of the polytetrafluoroethylene high-pressure reactor decreases at a rate of 5℃ / h until it cools to room temperature.
[0012] Preferably, in step S2, the property analysis of the crystal includes Fourier transform infrared spectroscopy analysis, single crystal X-ray diffraction analysis, X-ray powder diffraction analysis, thermogravimetric analysis, and X-ray photoelectron spectroscopy analysis.
[0013] Preferably, the Fourier transform infrared spectroscopy analysis is used to determine whether CdCoBTCHx crystals have been synthesized.
[0014] Preferably, the single-crystal X-ray diffraction analysis is used to determine the single-crystal structure of CdCoBTCHx.
[0015] Preferably, the X-ray powder diffraction analysis is used to determine the purity of CdCoBTCHx.
[0016] Preferably, the thermogravimetric analysis is used to determine the thermal stability of CdCoBTCHx.
[0017] Preferably, the X-ray photoelectron spectroscopy analysis is used to determine the valence state of CdCoBTCHx.
[0018] An application of a cadmium-cobalt bimetallic organic framework for the recognition of sulfur-containing amino acids.
[0019] The beneficial effects of this invention are that it synthesizes a cadmium-cobalt bimetallic organic framework (CdCoBTCHx), which is prepared by reacting 6-hydroxypurine and 1,3,5-pyromellitic acid with cadmium and cobalt ions. The presence of both Co(II) and Co(III) oxidation states in CdCoBTCHx significantly enhances the detection signals for cysteine and methionine, exhibiting good selectivity for sulfur-containing amino acids. UV-Vis absorption spectroscopy shows significant electron transfer between the MOF and guest molecules. Furthermore, the variable valence state of cobalt in CdCoBTCHx also promotes significant electron transfer during recognition, causing the solution color to change from colorless to yellow, thus providing visual recognition. This invention provides a technical reference for achieving rapid and visual detection of sulfur-containing compounds and has significant implications in the fields of biomedicine and food testing. Attached Figure Description
[0020] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 FT-IR spectrum of the synthesized product;
[0022] Figure 2 Single crystal structure of CdCoBTCHx crystal;
[0023] Figure 3 PXRD pattern of CdCoBTCHx crystal;
[0024] Figure 4 TGA image of CdCoBTCHx crystal;
[0025] Figure 5 XPS image of CdCoBTCHx crystal;
[0026] Figure 6 Changes in UV-Vis absorption spectra of L-cysteine and L-methionine after the addition of CdCoBTCHx. Detailed Implementation
[0027] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0028] A method for preparing a novel cadmium-cobalt bimetallic organic framework includes the following steps:
[0029] S1, Synthesis of cadmium-cobalt bimetallic organic framework;
[0030] Cd(NO3)2·4H2O, Co(NO3)2·6H2O, Hx, and H3BTC were placed in DMF solvent in a ratio of 2:1:2:1. After adjusting the pH with HNO3, the mixture was sealed in a polytetrafluoroethylene high-pressure reactor and heated at a constant temperature. Then, it was cooled to room temperature, filtered, and washed to obtain light purple crystals of CdCoBTCHx.
[0031] Wherein Hx is 6-hydroxypurine; H3BTC is 1,3,5-pyromellitic tricarboxylic acid; DMF solvent is N,N-dimethylformamide solvent; and CdCoBTCHx is a cadmium-cobalt bimetallic organic framework.
[0032] The concentration of HNO3 was 1 mol / L; the constant temperature heating was 140℃ for 72 h; after constant temperature heating, the temperature of the polytetrafluoroethylene high-pressure reactor decreased at a rate of 5℃ / h until it cooled to room temperature.
[0033] Property analysis of S2,CdCoBTCHx crystals.
[0034] The property analysis of crystals includes Fourier transform infrared spectroscopy (FT-IR), single crystal X-ray diffraction (SCXRD), X-ray powder diffraction (PXRD), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS).
[0035] Fourier transform infrared spectroscopy (FTIR) was used to determine whether CdCoBTCHx crystals had been synthesized. The light purple crystals synthesized in step S1 were filtered, dried, and then characterized using FTIR. Figure 1 As shown, the horizontal axis represents wavenumbers, and the vertical axis represents transmittance. (From...) Figure 1 We know that: 3132cm -1 The peak at approximately 1614 cm⁻¹ is the NH stretching vibration peak on the 6-hydroxypurine ligand. -1 Corresponding to the characteristic C=N absorption peak on the hydroxypurine ligand, 1562 cm⁻¹ -1 1439cm -1 1375cm -1 Corresponding to the characteristic absorption peak of the benzene ring on the BTC benzene ring, 1107 cm⁻¹ -1 The absorption corresponds to the CO stretching vibration on the BTC ligand, 768 cm⁻¹ -1 725cm -1The bending vibrations corresponding to the meta-substituent on the benzene ring of BTC indicate that CdCoBTCHx has been synthesized. CdCoBTCHx is a cadmium-cobalt bimetallic organic framework.
[0036] Single-crystal X-ray diffraction analysis was used to determine the single-crystal structure of CdCoBTCHx. Figure 2 a) shows the asymmetric unit cell of the CdCoBTCHx crystal, b) shows the metallic coordination mode, c) shows the three-dimensional framework formed along the b-axis, and d) shows the one-dimensional pores of CdCoBTCHx highlighted by an internal view of the Connolly surface.
[0037] The results show that CdCoBTCHx crystallizes in the monoclinic P2 system. 1 / n The space group, with its asymmetric unit, contains two metal centers (Cd1 / Co1 and Cd2), one 6-hydroxypurine, and one pyromellitic tricarboxylic acid molecule. The Cd1 / Co1 metal center is coordinated with five carboxylic acid O atoms from three BTC atoms, and one pyrimidine N atom and one imidazole N atom from two Hx atoms. The two symmetric Cd1 / Co1 metal centers are bridged by two carboxylic acid O atoms, ensuring that all benzene rings of the pyromellitic tricarboxylic acid are in the same plane. The Cd2 metal center is connected in a five-coordinate configuration to two carboxylic acid O atoms from one BTC atom, one pyrimidine N atom and one hydroxyl O atom outside the ring from one Hx atom, and one imidazole N atom from another Hx atom. Notably, the carboxylic acids in the BTC atoms are all coordinated with the metal in a bidentate configuration, and all N and O atoms in the Hx atoms are occupied by the metal. The two independent metal centers are linked by Hx, forming a three-dimensional network structure, and along the b-axis, forming a ring approximately... A one-dimensional channel.
[0038] X-ray powder diffraction analysis was used to determine the purity of CdCoBTCHx, such as Figure 3 As shown, the CdCoBTCHx crystal was tested by X-ray powder diffraction and compared with the standard pattern of the crystal structure simulation. The results showed that the diffraction peaks of the tested pattern and the simulation pattern were basically consistent, indicating that the obtained crystal had high purity.
[0039] Thermogravimetric analysis is used to determine the thermal stability of the purity of CdCoBTCHx, such as... Figure 4 As shown, CdCoBTCHx only causes the structure to completely collapse when heated to above 420 degrees Celsius, indicating that it has high thermal stability.
[0040] X-ray photoelectron spectroscopy analysis is used to determine the valence state of CdCoBTCHx, such as Figure 5 As shown, Figure 5 In the image, a is the full spectrum of CdCoBTCHx, and b is the high-resolution spectrum.
[0041] Figure 5 a confirmed the presence of Co, Cd, N, C, and O in CdCoBTCHx; by Figure 5 b shows that the Co 2p3 / 2 peak is located at 780.48 eV, accompanied by satellite peaks at 784.98 and 788.48 eV, and the Co 2p1 / 2 peak is located at 796.28 eV, with corresponding satellite peaks at 800.98 and 803.88 eV. These binding energy characteristics indicate the oxidation states of Co(II) and Co(III), suggesting that cobalt in CdCoBTCHx exists in a mixed valence state.
[0042] An application of a cadmium-cobalt bimetallic organic framework for the recognition of sulfur-containing amino acids.
[0043] When 5 mg of CdCoBTCHx was soaked in aqueous solutions (1.0 mM) of 20 common amino acids, the results showed that only the solutions of cysteine (Cys) and methionine (Met) underwent a significant color change from colorless to yellow, while no obvious changes were observed in the solutions of other amino acids.
[0044] CdCoBTCHx was added to L-cysteine and L-methionine at a concentration of 0.001 mol / L, and UV-Vis absorption spectroscopy analysis was performed. Figure 6 Figures a and b show the UV-Vis absorption spectra changes of L-cysteine and L-methionine after the addition of CdCoBTCHx, respectively. Analysis shows that after the addition of CdCoBTCHx, new absorption peaks rapidly appeared in the 260-375 nm range for both cysteine and methionine solutions, and the absorbance gradually increased over time, indicating a significant electron transfer between CdCoBTCHx and these two amino acids. These preliminary results suggest that CdCoBTCHx exhibits high selectivity for sulfur-containing amino acids, a phenomenon that may be closely related to the role of its mixed-valence metal sites.
[0045] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A method for preparing a cadmium-cobalt bimetallic organic framework, characterized in that, Includes the following steps: S1, Synthesis of cadmium-cobalt bimetallic organic framework; Cd(NO3)2·4H2O, Co(NO3)2·6H2O, Hx, and H3BTC were placed in DMF solvent in a ratio of 2:1:2:
1. After adjusting the pH with HNO3, the mixture was sealed in a polytetrafluoroethylene high-pressure reactor and heated at a constant temperature. Then, it was cooled to room temperature, filtered, and washed to obtain light purple crystals of CdCoBTCHx. In step S1, the concentration of HNO3 is 1 mol / L; the constant temperature heating temperature is 140℃ and the time is 72h; after constant temperature heating, the temperature of the polytetrafluoroethylene high-pressure reactor decreases at a rate of 5 °C / h until it cools to room temperature. Where Hx is 6-hydroxypurine; H3BTC is 1,3,5-pyromellitic tricarboxylic acid; DMF solvent is N,N-dimethylformamide solvent; CdCoBTCHx is cadmium cobalt bimetallic organic framework; Property analysis of S2,CdCoBTCHx crystals.
2. The method for preparing a cadmium-cobalt bimetallic organic framework according to claim 1, characterized in that, In step S2, the property analysis of the crystal includes Fourier transform infrared spectroscopy analysis, single crystal X-ray diffraction analysis, X-ray powder diffraction analysis, thermogravimetric analysis, and X-ray photoelectron spectroscopy analysis.
3. The method for preparing a cadmium-cobalt bimetallic organic framework according to claim 2, characterized in that, The Fourier transform infrared spectroscopy analysis was used to determine whether CdCoBTCHx crystals had been synthesized.
4. The method for preparing a cadmium-cobalt bimetallic organic framework according to claim 3, characterized in that, The single-crystal X-ray diffraction analysis was used to determine the single-crystal structure of CdCoBTCHx.
5. The method for preparing a cadmium-cobalt bimetallic organic framework according to claim 3, characterized in that, The X-ray powder diffraction analysis was used to determine the purity of CdCoBTCHx.
6. The method for preparing a cadmium-cobalt bimetallic organic framework according to claim 3, characterized in that, The thermogravimetric analysis was used to determine the thermal stability of CdCoBTCHx.
7. The method for preparing a cadmium-cobalt bimetallic organic framework according to claim 3, characterized in that, The X-ray photoelectron spectroscopy analysis was used to determine the valence state of CdCoBTCHx.
8. The application of the cadmium-cobalt bimetallic organic framework prepared by the method for preparing a cadmium-cobalt bimetallic organic framework according to any one of claims 1-7, characterized in that, It is used to identify sulfur-containing amino acids.