Zirconium-based metal organic framework material as well as preparation method and application thereof

Abstract

The invention discloses a zirconium-based metal organic framework material as well as a preparation method and application thereof, and belongs to the technical field of electrochemical luminescence (ECL). The zirconium-based metal organic framework material is UiO series typical fcu topology, a six-core metal cluster taking Zr6O4 (OH) 4 as a core is taken as a secondary structural unit (SBU), each Zr < 4 + > is coordinated with carboxyl oxygen of a ligand, and the six-core Zr cluster is bridged through the ligand to form a three-dimensional porous framework. The prepared illuminant Zr-MOF is simple in synthesis method, high in stability and good in electrochemical luminescence performance and can be used for ECL luminescence detection, and naphthalene rings and anthracene rings in ligands are excellent ECL illuminants.

Description

Technical Field

[0001] This invention relates to the field of electrochemiluminescence technology, specifically to a zirconium-based metal-organic framework material, its preparation method, and its application. Background Technology

[0002] Electrochemiluminescence (ECL) detection technology is a novel analytical technique that integrates electrochemical reactions and chemiluminescence. It combines the controllability of electrochemical analysis with the high sensitivity and low background interference of chemiluminescence analysis. By applying a specific potential to an electrode, a redox reaction is triggered in the system, generating excited-state substances. When these excited-state substances transition back to the ground state, they release photons. Quantitative analysis of the target substance is achieved by detecting the photon intensity, making it one of the important techniques in modern analytical detection. This technology is simple to operate, has a wide linear range, and produces no radioactive contamination. It exhibits unique advantages in detecting substances at extremely low concentrations in complex samples such as biological tissues and body fluids, and is particularly suitable for the ultrasensitive detection of disease biomarkers and trace environmental pollutants.

[0003] Currently, the core bottleneck in electrochemiluminescence detection technology lies in optimizing the performance of the electrochemiluminescence system, namely, how to improve luminescence efficiency, reduce trigger potential, and enhance detection stability and selectivity. Among existing electrochemiluminescence systems, commonly used luminescent materials include ruthenium terpyridine (Ru(bpy)3). 2+ Nanomaterials such as molybdenum disulfide (MoS2) and Ru(bpy)3 are included. 2+ Although the system has a wide range of applications, it suffers from problems such as limited luminescence efficiency, high cost, and complex labeling process. Although two-dimensional nanomaterials such as MoS2 have a large specific surface area and excellent electronic properties, their electrochemiluminescence efficiency is low, which limits their practical application range.

[0004] To address the aforementioned issues, those skilled in the art have attempted to modify the luminescent system by introducing catalysts or support materials. Metal-organic frameworks (MOFs), due to their ordered porous structure, large specific surface area, and tunable metal active sites, have become ideal anchoring substrates for support materials. Compared to traditional carbon-nitrogen-based materials, they can achieve stable anchoring under milder conditions. Currently, some studies have used MOFs for ECL sensing, such as the ZIF-8, UiO-66, or UiO-67 series. However, UiO series MOFs are primarily used as supports for ECL luminescent materials and do not emit light themselves. In 2018, Wei Qin's research group used ruthenium(II) complex Ru(bpy)3... 2+ Encapsulated in a UiO-67 metal-organic framework (ACS Appl. Mater. Interfaces 2018, 10, 22932-22938), forming UiO-67 / Ru(bpy)3 2+The nanocomposite material, UiO-67 MOF, possesses a large specific surface area and high porosity, enabling it to load more Ru(bpy)3 onto its surface and within its pores. 2+ This significantly improves ECL efficiency.

[0005] In the existing technology, UiO-67 / Ru(bpy)3 2+ The complex lacks stability, Ru(bpy)3 2+ Physically encapsulating the load within the MOF channels may pose a leakage risk. During long-term storage or repeated use, the luminescent material may leak out of the MOF framework, leading to signal attenuation and decreased reproducibility. During the synthesis process, Ru(bpy)3... 2+ The loading amount is difficult to control precisely. If the loading amount is too high, some ruthenium complexes may accumulate on the outer surface or pores of the MOF, causing self-quenching; if the loading amount is too low, the signal enhancement effect is limited, and the fluctuation of the loading amount between different batches will directly affect the quantitative accuracy of the sensor. The above defects significantly limit the universality of the strategy of using MOF as a carrier to load light-emitting elements. Summary of the Invention

[0006] To address the above technical problems, this invention provides a zirconium-based metal-organic framework material, its preparation method, and its application.

[0007] The first objective of this invention is to provide a method for preparing a zirconium-based metal-organic framework material, comprising the following steps: (1) 4-bromo-1-naphthoic acid, methanol and concentrated H2SO4 were mixed and heated under reflux to obtain methyl 4-bromo-1-naphthoic acid; (2) Take methyl 4-bromo-1-naphthyl ester, pinacol diboronate, the first catalyst and the alkaline substance and mix them in the reaction solvent. Heat the mixture under an inert atmosphere to obtain methyl 4-borono-1-naphthyl ester. (3) The obtained methyl 4-boronipina ester-1-naphthyl ester, methyl 10-bromo-9-anthracite, the second catalyst and cesium carbonate were mixed in the reaction solvent and heated under an inert atmosphere to obtain H2bpdc-AN-Me; (4) Using an aqueous solution of H2bpdc-AN-Me, methanol and alkali, heat under reflux to obtain the product H2bpdc-AN; (5) H2bpdc-AN and ZrCl4 are mixed and placed in a mixed solution containing organic solvent and growth regulator, and heated in stages to obtain the zirconium-based metal-organic framework material.

[0008] In some embodiments of the present invention, in step (1), the temperature of the heating reflux is 60-70°C and the time is 24-48h.

[0009] In some embodiments of the present invention, in step (2), the mass ratio of methyl 4-bromo-1-naphthyl ester, pinacol diboronate, the first catalyst, and the alkaline substance is 10.60:(11.17-35.1):(0.44-1.32):(11.78-35.34). The first catalyst comprises [1,1-bis(diphenylphosphine)ferrocene]palladium dichloride; The alkaline substance is selected from one or more of potassium acetate, sodium formate, and sodium acetate; The reaction solvent is selected from dioxane.

[0010] In some embodiments of the present invention, in step (2), the inert atmosphere includes nitrogen and / or argon; the heating reaction is carried out at a temperature of 100-120°C for 1-3 days.

[0011] In some embodiments of the present invention, in step (3), the mass ratio of methyl 4-boronopinarate-1-naphthyl ester, methyl 10-bromo-9-anthracite, the second catalyst, and cesium carbonate is (12.60-37.80):(0.92-2.76):(39.10-117.3). The inert gas in the inert atmosphere is selected from nitrogen and / or argon; the temperature for heating the reaction is 80-100℃, and the reaction time is 3-7 days; The second catalyst comprises tetratriphenylphosphine palladium.

[0012] In some embodiments of the present invention, in step (4), the concentration of the aqueous solution of alkali is 5 M, the temperature of the reflux is 80-100°C, and the time is 3-7 days; The alkali in the aqueous solution is selected from one or more of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide.

[0013] In some embodiments of the present invention, in step (5), the mass ratio of H2bpdc-AN to ZrCl4 is (5:3) to (5:5); The organic solvent includes DMF; The growth regulator is acetic acid.

[0014] In some embodiments of the present invention, the heating reaction is carried out in stages: the first stage is at a temperature of 100°C and the reaction lasts for 24 hours; the second stage is at a temperature of 120°C and the reaction lasts for 48 hours.

[0015] The second objective of this invention is to provide a zirconium-based metal-organic framework material prepared by the method described in the first objective. This zirconium-based metal-organic framework material exhibits a typical fcu topology of the UiO series, with a hexanuclear metal cluster (SBU) centered on Zr₆O₄(OH)₄ as the secondary structural unit. Each Zr₆O₄...4+ The hexanuclear Zr clusters coordinate with the carboxyl oxygen of the ligands and are bridged by the ligands to form a three-dimensional porous framework.

[0016] A third objective of this invention is to provide an electrochemiluminescent device comprising the zirconium-based metal-organic framework material.

[0017] The beneficial effects of this invention are: The present invention provides a simple and stable method for synthesizing Zr-MOF luminescent materials, which can be used for ECL luminescence detection. The naphthalene and anthracene rings in the ligands are excellent ECL luminescent materials. The biphenyl acid ligand of UiO-67 has low conjugation and almost no optical activity; the anthracene + naphthalene ring in the Zr-MOF ligand forms a super-large conjugated π system, significantly improving the molar extinction coefficient and fluorescence quantum yield of Zr-MOF synthesized using it as a ligand, thus exhibiting highly efficient ECL luminescence performance. Furthermore, the rigid structure of the fused ring reduces molecular vibration / rotation, greatly reducing the non-radiative energy consumption of the excited state, allowing more excited states to emit light through radiative transitions, directly improving ECL efficiency.

[0018] The Zr-MOF obtained in this invention has a large conjugated fused ring structure and can itself serve as an ECL luminescent material without the need for additional Ru(bpy)3 loading. 2+ This avoids the problems of light source leakage and uneven distribution from the root cause.

[0019] This invention utilizes the stronger rigidity of fused-ring ligands, resulting in a more stable MOF structure and better pore regularity, which enables precise control of the luminescent element spacing and effectively suppresses concentration self-quenching. At the same time, the rigidity and conjugation of the fused-ring ligands make Zr-O coordination more robust, making the MOF less prone to collapse under acid-base and electrochemical scanning conditions, thus extending its service life. Attached Figure Description

[0020] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 These are the specific steps for synthesizing the H2bpdc-AN ligand of this invention.

[0021] Figure 2 This is a structural diagram of UiO-67-AN synthesized in Example 1 of the present invention.

[0022] Figure 3 This is the XRD result diagram of UiO-67-AN synthesized in Example 1 of the present invention.

[0023] Figure 4 The UiO-67 provided in Comparative Example 1 of this invention is used for ECL luminescence.

[0024] Figure 5The UiO-67-AN synthesized in Example 1 of this invention is used for ECL luminescence. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention. Example 1

[0026] This embodiment provides a method for preparing UiO-67-AN material, as detailed below: (1) Synthesis of methyl 4-bromo-1-naphthyl ester 9.20 g of 4-bromo-1-naphthic acid, 300 mL of methanol, and 3 mL of concentrated H₂SO₄ were mixed and refluxed at 65 °C for 24 h. After cooling, the mixture was diluted with water, and then 2 M NaHCO₃ was added to neutralize the sulfuric acid in the product. The product was extracted repeatedly with CH₂Cl₂ until no target product was found in the aqueous phase, and then dried with anhydrous Na₂SO₄. After removing CH₂Cl₂, a pale yellow solid, methyl 4-bromo-1-naphthic acid, was obtained.

[0027] (2) Synthesis of methyl 4-boronapina ester-1-naphthyl ester Weigh 10.60 g of methyl 4-bromo-1-naphthyl ester, 11.17 g of pinacol diboronate, 0.44 g of [1,1-bis(diphenylphosphine)ferrocene]palladium dichloride, and 11.78 g of potassium acetate obtained in step (1). Place them in a 1000 mL three-necked flask and add 300 mL of anhydrous dioxane. React at 100 °C for 1 day under nitrogen atmosphere. After the reaction is completed, cool to room temperature, remove dioxane, extract with deionized water and dichloromethane, and evaporate the dichloromethane solution to dryness to obtain the crude product. Then purify the product by column chromatography with dichloromethane as the eluent. Finally, obtain the product methyl 4-boronpinacol-1-naphthyl ester. Freeze the product in a refrigerator for later use.

[0028] (3) Synthesis of H2bpdc-AN-Me The products synthesized in step (2), including methyl 4-boronopinarate-1-naphthyl ester, methyl 10-bromo-9-anthracite (12.60 g), tetra-triphenylphosphine palladium (0.92 g), and cesium carbonate (39.10 g), were added to a 1000 ml three-necked flask. 500 ml of anhydrous dioxane was added, and the mixture was reacted at 90 °C under nitrogen for three days. After the reaction was completed, the mixture was cooled to room temperature, the dioxane solution was removed, the crude product was dried, and 300 ml of water was added to dissolve it by sonication. The organic phase was then extracted with dichloromethane, and the dichloromethane was removed. The product was then purified by column chromatography using a dichloromethane:petroleum ether eluent with a volume ratio of 1:4. The final product was H2bpdc-AN-Me.

[0029] (4) Synthesis of H2bpdc-AN The product H2bpdc-AN-Me obtained in step (3) was placed in a 1000 ml flask, 300 ml of methanol and 150 ml of 5 M sodium hydroxide aqueous solution were added, and the mixture was refluxed at 100 °C for three days. After the reaction was completed, the mixture was cooled to room temperature, methanol was removed, and deionized water was added until the solution was clear. Hydrochloric acid was added to the clear solution until pH=1. The mixture was filtered, and the filter cake was dried in an 80 °C vacuum drying oven to obtain the product H2bpdc-AN.

[0030] (5) Synthesis of UiO-67-AN Weigh 100 mg H2bpdc-AN and 60 mg ZrCl4 obtained in step (4) and place them in a 20 ml glass vial containing 10 ml DMF and 0.5 ml acetic acid. The reaction system was kept at 100 °C for 24 hours, and then at 120 °C for 48 hours. The vial was shaken twice during the reaction to ensure thorough mixing of the reactants. After the reaction, UiO-67-AN, i.e., Zr-MOF, was obtained. Before performing other tests or characterizations, the obtained MOF was washed three times each with DMF and acetone to remove over-modifiers not incorporated into the MOFs and residual DMF in the lattice. The obtained Zr-MOF was structurally characterized, and the experimental results are shown in [Figure number missing]. Figure 3 ,Depend on Figure 3 It can be seen that all the characteristic diffraction peaks of the experimental curve correspond perfectly to the peak positions of the simulated curve. This indicates that the crystal structure and cell parameters of the experimental sample are completely consistent with the target UiO-67-AN structure, and no structural collapse, phase transformation or impurity phase generation has occurred.

[0031] Comparative Example 1 This comparative example provides a conventional metal-organic framework material, UiO-67.

[0032] Application examples The electrochemiluminescence properties of the UiO-67-AN material obtained in Example 1 and the UiO-67 in Comparative Example 1 were tested.

[0033] The electrochemiluminescence performance of the UiO-67-AN material obtained in Example 1 and the UiO-67 in Comparative Example 1 was tested. The experimental procedure was as follows: a classic three-electrode system consisting of a glassy carbon electrode modified with UiO-67-AN or UiO-67, a platinum electrode, and a silver / silver chloride electrode was inserted into an electrolytic cell containing 5 mL of 10 mM potassium persulfate. The electrolytic cell was then placed in a Xi'an Ruimai MPI-E electrochemiluminescence analyzer for electrochemiluminescence performance testing. The experimental results are shown below. Figure 4 and Figure 5 ,Depend on Figure 4As can be seen, when the classic UiO-67 is tested for electrochemiluminescence performance in an electrochemiluminescence analyzer, the electrochemiluminescence intensity is approximately 1000 au. (From...) Figure 5 As can be seen, the electrochemiluminescence intensity of UiO-67-AN prepared by this invention is approximately 18000 au, which is about 18 times higher than that of traditional UiO-67. Furthermore, its stability remains good after 10 cycles.

[0034] The embodiments described above are merely preferred embodiments for fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for preparing a zirconium-based metal-organic framework material, characterized in that, Includes the following steps: (1) 4-bromo-1-naphthoic acid, methanol and concentrated H2SO4 were mixed and heated under reflux to obtain methyl 4-bromo-1-naphthoic acid; (2) Take methyl 4-bromo-1-naphthyl ester, pinacol diboronate, the first catalyst and the alkaline substance and mix them in the reaction solvent. Heat the mixture under an inert atmosphere to obtain methyl 4-borono-1-naphthyl ester. (3) The obtained methyl 4-boronipina ester-1-naphthyl ester, methyl 10-bromo-9-anthracite, the second catalyst and cesium carbonate were mixed in the reaction solvent and heated under an inert atmosphere to obtain H2bpdc-AN-Me; (4) Using an aqueous solution of H2bpdc-AN-Me, methanol and alkali, heat under reflux to obtain the product H2bpdc-AN; (5) H2bpdc-AN and ZrCl4 are mixed and placed in a mixed solution containing organic solvent and growth regulator, and heated in stages to obtain the zirconium-based metal-organic framework material.

2. The preparation method according to claim 1, characterized in that, In step (1), the temperature of the reflux heating is 60-70℃ and the time is 24-48h.

3. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of methyl 4-bromo-1-naphthyl ester, pinacol diboronate, the first catalyst, and the alkaline substance is 10.60:(11.17-35.1):(0.44-1.32):(11.78-35.34). The first catalyst comprises [1,1-bis(diphenylphosphine)ferrocene]palladium dichloride; The alkaline substance is selected from one or more of potassium acetate, sodium formate, and sodium acetate; The reaction solvent is selected from dioxane.

4. The preparation method according to claim 1, characterized in that, In step (2), the inert atmosphere includes nitrogen and / or argon; the heating temperature is 100-120℃ and the time is 1-3 days.

5. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of methyl 4-boronate-1-naphthyl ester, methyl 10-bromo-9-anthracite, the second catalyst, and cesium carbonate is 5: (12.60-37.80): (0.92-2.76): (39.10-117.3). The inert gas in the inert atmosphere is selected from nitrogen and / or argon; the temperature for heating the reaction is 80-100℃, and the reaction time is 3-7 days; The second catalyst comprises tetratriphenylphosphine palladium.

6. The preparation method according to claim 1, characterized in that, In step (4), the concentration of the alkali aqueous solution is 5 M, the reflux temperature is 80-100℃, and the time is 3-7 days; The alkali in the aqueous solution is selected from one or more of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide.

7. The preparation method according to claim 1, characterized in that, In step (5), the mass ratio of H2bpdc-AN to ZrCl4 is (5:3) - (5:5); The organic solvent includes DMF; The growth regulator is acetic acid.

8. The preparation method according to claim 1, characterized in that, The reaction is carried out in two stages: the first stage is at 100°C and lasts for 24 hours; the second stage is at 120°C and lasts for 48 hours.

9. A zirconium-based metal-organic framework material, characterized in that, The zirconium-based metal-organic framework material, prepared by the method described in any one of claims 1-8, is a typical fcu topology of the UiO series, with a hexanuclear metal cluster (SBU) as the core of Zr6O4(OH)4 as the secondary structural unit. 4+ The hexanuclear Zr clusters coordinate with the carboxyl oxygen of the ligands and are bridged by the ligands to form a three-dimensional porous framework.

10. An electrochemiluminescence device, characterized in that, Includes the zirconium-based metal-organic framework material as described in claim 9.

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