Uranium-based metal-organic framework material, and preparation method and application thereof

Abstract

The application discloses a uranium-based metal organic framework material and a preparation method and application thereof, and the chemical formula of the uranium-based metal organic framework material is [(UO2 2+ )(H2L 2‑ )·H2O] n , [(UO2 2+ )3(HL 3‑ )2(H2O)3·3H2O] n or [(UO2 2+ )(H2L 2‑ )·2H2O] n , wherein n is an integer greater than 0, and L is an aromatic tetracarboxylic acid. A series of uranium-based MOF materials are synthesized by using a solvent-thermal method, the X-ray stability of the MOF structure is significantly improved by using the strategy of preparing luminescent uranium-based MOF materials by using flexible carboxylic acid aromatic ligands, the prepared uranium-based MOF material has the advantages of diversified structure, stable property, excellent performance and wide application range, and the uranium-based MOF material is applied to the imaging field for the first time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal organic framework materials, in particular to a uranium-based metal organic framework material and a preparation method and application thereof. BACKGROUND

[0002] X-ray imaging technology has shown wide application value in many fields due to its excellent penetration ability. In medical diagnosis, X-ray imaging as a key diagnostic tool is of great significance for early detection and treatment of diseases. In daily life, various security check equipment also widely uses X-ray imaging technology to detect prohibited items to ensure public safety. In the industrial field, especially in the aviation, automobile, electronics and other industries, X-ray imaging as an important means of non-destructive testing (NDT) can detect internal defects and cracks of materials, which is crucial for ensuring product quality and safety. In addition, X-ray imaging also plays an important role in radiation detection and scientific research, providing strong support for observing and analyzing the microstructure of samples.

[0003] However, the effect of X-ray imaging technology depends largely on the imaging material used. At present, a variety of materials have been developed for X-ray imaging, such as inorganic scintillator materials and organic scintillator materials. Inorganic scintillator materials, such as CsI:Tl (cesium iodide doped with thallium), NaI:Tl (sodium iodide doped with thallium), Bi4Ge3O 12 (BGO), LaBr3:Ce (lanthanum bromide doped with cerium), etc., although have the advantages of high light output, fast response time and high density, are prone to deliquescence, have poor stability, and need to be replaced frequently, which not only causes a large amount of resource waste and cost increase, but also puts additional pressure on the environment. In contrast, organic scintillator materials, such as plastic scintillator polystyrene, polyethylene, liquid scintillator aromatic compound solution, and crystalline organic scintillator anthracene, phenanthrene, etc., although have good stability, their preparation process is complex, and due to the lack of heavy atoms for the deposition of rays, the performance improvement is limited and the energy utilization rate is not high.

[0004] In order to overcome the shortcomings of the above-mentioned materials, in recent years, organic-inorganic hybrid materials, such as metal-organic frameworks (MOFs) and perovskite materials, have attracted much attention due to their combination of the advantages of inorganic materials and organic materials, and to some extent, the avoidance of the disadvantages of both. Among them, perovskite materials have excellent photoelectric properties and adjustable band gap, which can realize efficient conversion of X-rays to photons. Metal-organic frameworks (MOFs) can precisely control the pore size, performance and surface properties of the material by combining inorganic metal ions and organic ligands, thereby optimizing its absorption of X-rays and energy transfer efficiency, and showing good application prospects in X-ray imaging.

[0005] In MOF materials, heavy elements are usually contained to improve the absorption efficiency of X-rays. For example, lead-based MOF materials use heavy metal inorganic units with high X-ray attenuation efficiency as X-ray absorption functional units, which transfer energy to the luminescent ligand, making the material exhibit good performance. Metal cluster-based MOF materials improve the X-ray deposition capacity through high-density metal clusters, and then match the luminescent ligand to improve the luminescent performance of the MOF material. In addition, the luminescent performance of metal elements themselves can also be used, such as lanthanide elements and other metal elements that emit light due to their large atomic number and antenna effect, which are also applied to MOF materials.

[0006] However, although uranium has a larger atomic number and stronger X-ray deposition effect, and has intrinsic fluorescence, it is a promising X-ray imaging material, but it is subject to X-ray radiation stability, and no successful application of uranium-based MOF materials in the imaging field has been found. Moreover, existing X-ray imaging materials have problems such as low X-ray utilization efficiency, poor stability, and complex preparation, and some uranium-based MOF materials cannot be successfully applied in the imaging field due to insufficient radiation stability or poor fluorescence performance.

[0007] Therefore, it is of great significance to develop a uranium-based MOF material with excellent X-ray absorption and energy conversion efficiency, and good radiation stability, to promote the development of X-ray imaging technology. SUMMARY

[0008] To solve the above technical problems, the present application provides a uranium-based metal organic framework material and a preparation method and application thereof.

[0009] The present application is realized by the following technical solutions:

[0010] The present application provides a uranium-based metal organic framework material in the first aspect, and the chemical formula of the uranium-based metal organic framework material is [(UO2 2+ )(H2L 2- )·H2O] n , [(UO2 2+ )3(HL 3- )2(H2O)3·3H2O] n or [(UO2 2+ )(H2L 2- )·2H2O] n , wherein n is an integer greater than 0, and L is an organic ligand with the following structure:

[0011]

[0012] Further, the uranium-based metal organic framework material [(UO2 2+ )(H2L 2- )·H2O]n The chemical formula can also be (C 14 H 10 N2O 11 U) n .

[0013] Further, the chemical formula of the uranium-based metal organic framework material [(UO2 2+ )3(HL 3- )2(H2O)3·3H2O] n The chemical formula can also be (C 28 H 34 N4O 32 U3) n .

[0014] Further, the chemical formula of the uranium-based metal organic framework material [(UO2 2+ )(H2L 2- )·2H2O] n The chemical formula can also be (C 14 H 12 N2O 12 U) n .

[0015] The second aspect of the present application provides a preparation method of a uranium-based metal organic framework material, comprising the following steps:

[0016] The aromatic tetracarboxylic acid and uranyl nitrate are dissolved in a mixed solvent of an organic solvent and water at 80-140 DEG C, and a coordination reaction occurs after adding nitric acid to obtain the uranium-based metal organic framework material; the organic solvent is selected from one of acetonitrile, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), N-methyl pyrrolidone (NMP) and N, N-diethylformamide (DEF).

[0017] The present application adopts a solvothermal method to synthesize a series of uranium-based MOF materials, and the prepared uranium-based MOF materials have various structures, stable properties, excellent performance and wide application range.

[0018] The present application significantly improves the X-ray stability of the MOF structure by adopting the strategy of preparing a luminescent uranium-based MOF material by using a flexible carboxylic acid aromatic ligand, so that the uranium-based MOF material can be more widely applied in the imaging field.

[0019] Furthermore, the aromatic tetracarboxylic acid is an organic ligand, which can be 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid, with the structural formula shown below.

[0020] Furthermore, the molar ratio of the aromatic tetracarboxylic acid to uranyl nitrate is (0.5-2):1.

[0021] Furthermore, the volume ratio of the organic solvent to water is (0.5-5):(1.5-6).

[0022] Furthermore, the amount of nitric acid added is 1-14 drops, with one drop being 0.02-0.05 mL.

[0023] Furthermore, the volume ratio of the organic solvent to nitric acid is (0.5-5):(0.02-0.7).

[0024] Furthermore, the coordination reaction takes 2-14 days.

[0025] Further, at 100-140℃, aromatic tetracarboxylic acid (L) and uranyl nitrate are dissolved in a mixed solvent of organic solvent and water. After adding nitric acid, the volume ratio of the organic solvent, water, and nitric acid is (3-5):(1.5-3):(0.14-0.7). After a coordination reaction takes place for 2-7 days, the uranium-based metal-organic framework material [(UO2]] is obtained. 2+ (H2L) 2- )·H2O] n .

[0026] In a specific embodiment, 0.03-0.1 mmol of aromatic tetracarboxylic acid (L) and 0.03-0.1 mmol of uranyl nitrate are dissolved in a mixed solvent of 3-5 mL of organic solvent and 1.5-3 mL of water. After adding 7-14 drops of nitric acid, the mixture is heated at 100-140°C for 1-3 days, cooled for 5-10 minutes, and then heated again at 100-140°C for 1-4 days to obtain the uranium-based metal-organic framework material [(UO2]]. 2 + (H2L) 2- )·H2O] n .

[0027] Further, at 80-110℃, aromatic tetracarboxylic acid (L) and uranyl nitrate are dissolved in a mixed solvent of organic solvent and water. After adding nitric acid, the volume ratio of the organic solvent, water, and nitric acid is (0.5-2):(3-6):(0.02-0.1). After a coordination reaction takes place for 4-10 days, the uranium-based metal-organic framework material [(UO2]] is obtained. 2+ )3(HL 3- )2(H2O)3·3H2O] n.

[0028] In a specific embodiment, 0.03-0.1 mmol aromatic tetracarboxylic acid (L) and 0.03-0.1 mmol uranyl nitrate are dissolved in 0.5-2 mL of a mixed solvent of organic solvent and 3-6 mL of water, 1-2 drops of nitric acid are added dropwise, and then heated at 80-110 °C for 1-3 days. After cooling for 15-20 minutes, heating at 80-110 °C for another 3-6 days, and cooling for 1-1.5 hours, the uranium metal-organic framework material [(UO2 2+ )(H2L 3- )2(H2O)3·3H2O] is obtained. n .

[0029] Further, 0.03-0.1 mmol aromatic tetracarboxylic acid (L) and 0.03-0.1 mmol uranyl nitrate are dissolved in a mixed solvent of organic solvent and water at 80-100 °C, and after adding nitric acid, the volume ratio of the organic solvent, water and nitric acid is (0.5-2):(3-6):(0.12-0.4). After 7-14 days of coordination reaction, the uranium metal-organic framework material [(UO2 2+ )(H2L 2- )·2H2O] is obtained. n .

[0030] In a specific embodiment, 0.03-0.1 mmol aromatic tetracarboxylic acid (L) and 0.03-0.1 mmol uranyl nitrate are dissolved in 0.5-2 mL of a mixed solvent of organic solvent and 3-6 mL of water, 6-8 drops of nitric acid are added dropwise, and then heated at 80-100 °C for 1-3 days. After cooling for 15-20 minutes, heating at 80-110 °C for another 3-6 days, cooling for 1-1.5 hours, and then heating at 80-110 °C for another 3-5 days, the uranium metal-organic framework material [(UO2 2+ )(H2L 2- )·2H2O] is obtained. n .

[0031] In a specific embodiment, the preparation method comprises the following steps:

[0032] The aromatic tetracarboxylic acid and uranyl nitrate are placed in a container, a mixed solvent of organic solvent and water is added to the container, nitric acid is added, and then the container is placed in an oven and heated at 80-140 °C for a period of time. After cooling at room temperature, heating in the oven at 80-140 °C is performed again to obtain the uranium metal-organic framework material.

[0033] Further, after heating is completed, steps of washing with an organic solvent and drying treatment are further included.

[0034] Specifically, aromatic tetracarboxylic acid and uranyl nitrate are placed in a container, a mixed solvent of acetonitrile and water is added to the container, nitric acid is added, and then the container is capped after mixing; the container is placed in an oven and heated at 80-140 DEG C for a certain period of time, then cooled at room temperature for a certain period of time, and then placed in the oven again and heated at 80-140 DEG C for a certain period of time, and then washed with acetonitrile and naturally dried to obtain the uranium-based metal organic framework material.

[0035] The third aspect of the present application provides the use of the uranium-based metal organic framework material of the first aspect or the uranium-based metal organic framework material prepared by the method of the second aspect in the field of X-ray imaging.

[0036] Under the irradiation of low-dose rate X-rays of more than 325 muGy / s, the uranium-based metal organic framework material provided by the present application can emit green fluorescence (qualitative detection), and the luminescence intensity is proportional to the radiation dose rate (quantitative detection).

[0037] The present application improves the radiation stability of the uranium-based MOF material in X-ray imaging, and the several uranium-based MOF materials provided by the present application can emit light under X-ray excitation and still maintain high initial performance after long-time high-dose rate X-ray irradiation, thereby overcoming the shortcomings of the previous uranium-based MOF scintillating materials in radiation stability. The improved radiation stability makes it possible to apply the uranium-based MOF material in X-ray imaging, and provides a new material selection and research direction for the application exploration of the uranium-based MOF material and the utilization of depleted uranium resources.

[0038] The beneficial effects of the present application are:

[0039] The present application significantly enhances the structural diversity by adopting the flexible design of the ligand, successfully synthesizes a series of uranium-based MOF materials with unique properties, and effectively retains the original fluorescence performance of uranyl. In addition, the design also greatly improves the X-ray stability of the material, so that the prepared film material not only retains excellent imaging performance, but also has the ability to be repeatedly used, thereby greatly expanding the utilization way of nuclear waste depleted uranium. The present application not only provides a design method for a new type of uranium-based MOF material, but also provides a new application prospect for the uranium-based MOF material. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The structure of the uranium-based metal organic framework material [(UO2 2+ )(H2L 2- )·H2O] n is shown in the structure bond line diagram.

[0041] Figure 2 The structure of the uranium-based metal organic framework material [(UO2 2+ )(H2L2- )·H2O] n schematic diagram of the structure of the uranium-based metal-organic framework material.

[0042] Figure 3 is a uranium-based metal-organic framework material [(UO2 2+ )3(HL 3- )2(H2O)3·3H2O] n schematic diagram of the structure of the uranium-based metal-organic framework material.

[0043] Figure 4 is a uranium-based metal-organic framework material [(UO2 2+ )3(HL 3- )2(H2O)3·3H2O] n schematic diagram of the structure of the uranium-based metal-organic framework material.

[0044] Figure 5 is a uranium-based metal-organic framework material [(UO2 2+ )(H2L 2- )·2H2O] n schematic diagram of the structure of the uranium-based metal-organic framework material.

[0045] Figure 6 is a uranium-based metal-organic framework material [(UO2 2+ )(H2L 2- )·2H2O] n schematic diagram of the structure of the uranium-based metal-organic framework material.

[0046] Figure 7 is a comparison diagram of powder diffraction of the uranium-based metal-organic framework material prepared in Example 1 and simulation.

[0047] Figure 8 is a comparison diagram of powder diffraction of the uranium-based metal-organic framework material prepared in Example 4 and simulation.

[0048] Figure 9 is a comparison diagram of powder diffraction of the uranium-based metal-organic framework material prepared in Example 7 and simulation.

[0049] Figure 10 is a photograph and an X-ray imaging diagram of a flexible scintillator film prepared from the uranium-based metal-organic framework material prepared in Example 1; wherein (a) is the photograph, and (b) is the X-ray imaging diagram.

[0050] Figure 11 is a diagram of the stability test results of the uranium-based metal-organic framework material prepared in Example 1 and a previous uranium-based MOF material for X-ray imaging.

[0051] Figure 12 is a diagram of the reusability test results of the uranium-based metal-organic framework material prepared in Example 1 for X-ray imaging. Detailed Implementation

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0053] The first aspect of this invention provides a uranium-based metal-organic framework material, wherein the chemical formula of the uranium-based metal-organic framework material is [(UO2)]. 2+ (H2L) 2- )·H2O] n 、[(UO2 2+ )3(HL 3- )2(H2O)3·3H2O] n or [(UO2) 2+ (H2L) 2- )·2H2O] n Where n is a positive integer, and L is an organic ligand with the following structure:

[0054]

[0055] Uranium-based metal-organic framework materials [(UO2) 2+ (H2L) 2- )·H2O] n The structural keyline diagram in the CCDC database is as follows: Figure 1 As shown, the structural diagram in the crystal visualization software CrystalMaker is as follows: Figure 2 As shown, the polyhedron represents the center of the metal U, and the others are aromatic ring frameworks.

[0056] Uranium-based metal-organic framework materials [(UO2) 2+ )3(HL 3- )2(H2O)3·3H2O] n The structural keyline diagram in the CCDC database is as follows: Figure 4 As shown, the structural diagram in the crystal visualization software CrystalMaker is as follows: Figure 4 As shown, the polyhedron represents the center of the metal U, and the others are aromatic ring frameworks.

[0057] Uranium-based metal-organic framework materials [(UO2) 2+ (H2L) 2- )·2H2O] n The structural keyline diagram in the CCDC database is as follows: Figure 6The structure diagram shown in the crystal visualization software CrystalMaker is as follows Figure 6 The structure diagram shown in the crystal visualization software CrystalMaker is as follows

[0058] The application will be further described below in conjunction with the drawings and specific examples, so that those skilled in the art can better understand the application and implement it, but the examples are not intended to limit the application.

[0059] The experimental methods used in the following examples are conventional methods, and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0060] Example 1

[0061] A preparation method of a uranium-based metal organic framework material, comprising the following steps:

[0062] 0.05 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.05 mmol of uranyl nitrate are weighed into a crimp vial, 4 mL of acetonitrile and 2 mL of water are added, and 7 drops of nitric acid are added dropwise using a dropper. The cap is tightened and placed in an oven at 120°C for heating for 1 day. After cooling at room temperature for 5 minutes, the crimp vial is placed in an oven at 120°C for heating for 1 day. After cooling, the yellow crystals are washed twice with acetonitrile and dried at room temperature to obtain pure yellow crystals, i.e. the uranium-based metal organic framework material [(UO2 2+ )(H2L 2- )·H2O] n .

[0063] Figure 7 The powder diffraction comparison diagram of the uranium-based metal organic framework material prepared in Example 1 and simulation is shown in the figure. The black represents the simulated cluster powder diffraction diagram, and the red represents the cluster powder diffraction diagram synthesized in Example 1. The corresponding diffraction peaks of the simulation and experimental diagram prove that the cluster structure is successfully synthesized and has high purity.

[0064] Example 2

[0065] A preparation method of a uranium-based metal organic framework material, comprising the following steps:

[0066] 0.03 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.06 mmol of uranyl nitrate are weighed into a crimp vial, 3 mL of DMF and 3 mL of water are added, and 14 drops of nitric acid are added dropwise using a dropper. The cap is tightened and placed in an oven at 100°C for heating for 2 days. After cooling at room temperature for 10 minutes, the crimp vial is placed in an oven at 100°C for heating for 2 days. After cooling, the yellow crystals are washed 5 times with acetonitrile and dried at room temperature to obtain pure yellow crystals, i.e. the uranium-based metal organic framework material [(UO22+ (H2L 2- )·H2O] n .

[0067] Example 3

[0068] A method for preparing a uranium-based metal organic framework material, comprising the following steps:

[0069] Take 0.06 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.03 mmol of uranyl nitrate into a crimp vial, add 5 mL of DMA and 1.5 mL of water, then drop 10 drops of nitric acid with a dropper, tighten the cap and place it in an oven at 140°C for 3 days. After cooling at room temperature for 7 minutes, place it in an oven at 140°C for 4 days. After cooling, wash it with acetonitrile for 3 times, and dry it at room temperature to obtain pure yellow crystals, which are the uranium-based metal organic framework material [(UO2 2+ (H2L 2- )·H2O] n .

[0070] It is tested that the uranium-based metal organic framework material is successfully prepared in Example 2 and Example 3.

[0071] Example 4

[0072] A method for preparing a uranium-based metal organic framework material, comprising the following steps:

[0073] Take 0.05 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.05 mmol of uranyl nitrate into a crimp vial, add 1 mL of acetonitrile and 5 mL of water, then drop 1 drop of nitric acid with a dropper, tighten the cap and place it in an oven at 100°C for 1 day. After cooling at room temperature for 20 minutes, place it in an oven at 100°C for 3 days. After cooling, wash it with acetonitrile for 2 times, and dry it at room temperature to obtain pure yellow crystals, which are the uranium-based metal organic framework material [(UO2 2+ (H2L 3- )2(H2O)3·3H2O] n .

[0074] Figure 8 The powder diffraction comparison chart of the uranium-based metal organic framework material prepared in Example 4 and simulation is shown in the figure. The black represents the simulated cluster powder diffraction chart, and the red represents the cluster powder diffraction chart synthesized in Example 4. The corresponding diffraction peaks of the simulation and experimental chart prove that the cluster structure is successfully synthesized and has high purity.

[0075] Example 5

[0076] A method for preparing a uranium-based metal organic framework material, comprising the following steps:

[0077] Take 0.05 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.1 mmol of uranyl nitrate into a screw cap bottle, add 0.5 mL of NMP and 6 mL of water, then drop 2 drops of nitric acid with a dropper, tighten the cap and place it in an oven at 80°C for 3 days. After cooling for 20 minutes at room temperature, place it in an oven at 80°C for another 6 days. After cooling, wash it with acetonitrile for 5 times and dry it at room temperature to obtain pure yellow crystals, which are uranium metal-organic framework material [(UO2 2+ )3(HL 3- )2(H2O)3·3H2O] n .

[0078] Example 6

[0079] A method for preparing a uranium metal-organic framework material, comprising the following steps:

[0080] Take 0.1 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.1 mmol of uranyl nitrate into a screw cap bottle, add 2 mL of DEF and 3 mL of water, then drop 2 drops of nitric acid with a dropper, tighten the cap and place it in an oven at 100°C for 2 days. After cooling for 15 minutes at room temperature, place it in an oven at 100°C for another 4 days. After cooling, wash it with acetonitrile for 3 times and dry it at room temperature to obtain pure yellow crystals, which are uranium metal-organic framework material [(UO2 2+ )3(HL 3- )2(H2O)3·3H2O] n .

[0081] It is tested that the uranium metal-organic framework material is also successfully prepared in Example 5 and Example 6.

[0082] Example 7

[0083] A method for preparing a uranium metal-organic framework material, comprising the following steps:

[0084] Take 0.05 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.05 mmol of uranyl nitrate into a screw cap bottle, add 1 mL of acetonitrile and 5 mL of water, then drop 6 drops of nitric acid with a dropper, tighten the cap and place it in an oven at 100°C for 1 day. After cooling for 20 minutes at room temperature, place it in an oven at 100°C for another 3 days. After cooling for more than 1 hour, continue to place it in an oven at 100°C for 5 days until crystals appear. After cooling at room temperature, wash it with acetonitrile for 2 times and dry it at room temperature to obtain pure yellow crystals, which are uranium metal-organic framework material [(UO2 2+ )(H2L2- )·2H2O] n .

[0085] Figure 9 The powder diffraction comparison chart of the uranium-based metal organic framework material prepared in Example 7 and simulation is shown in the figure, the black represents the simulated cluster powder diffraction chart, and the red represents the cluster powder diffraction chart synthesized in Example 7. The corresponding diffraction peaks of the simulation and experimental atlas prove that the cluster structure is successfully synthesized and has high purity.

[0086] Example 8

[0087] A preparation method of a uranium-based metal organic framework material, comprising the following steps:

[0088] 0.1 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.05 mmol of uranyl nitrate were weighed into a screw cap bottle, 0.5 mL of acetonitrile and 3 mL of water were added, 7 drops of nitric acid were added dropwise with a dropper, the cap was tightened and placed in an oven at 90°C for heating for 2 days. After the reaction was cooled at room temperature for 20 minutes, it was placed in an oven at 90°C for heating for 5 days. After being taken out and cooled for more than 1 hour, it was continuously placed in an oven at 90°C for heating for 4 days until crystals appeared. After being cooled at room temperature, it was washed with acetonitrile for 3 times and dried at room temperature to obtain pure yellow crystals, i.e. a uranium-based metal organic framework material [(UO2 2+ )(H2L 2- )·2H2O] n .

[0089] Example 9

[0090] A preparation method of a uranium-based metal organic framework material, comprising the following steps:

[0091] 0.08 mmol of 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and 0.04 mmol of uranyl nitrate were weighed into a screw cap bottle, 2 mL of acetonitrile and 6 mL of water were added, 8 drops of nitric acid were added dropwise with a dropper, the cap was tightened and placed in an oven at 80°C for heating for 3 days. After the reaction was cooled at room temperature for 20 minutes, it was placed in an oven at 80°C for heating for 6 days. After being taken out and cooled for more than 1 hour, it was continuously placed in an oven at 80°C for heating for 3 days until crystals appeared. After being cooled at room temperature, it was washed with acetonitrile for 5 times and dried at room temperature to obtain pure yellow crystals, i.e. a uranium-based metal organic framework material [(UO2 2+ )(H2L 2- )·2H2O] n .

[0092] It is tested that the uranium-based metal organic framework material is also successfully prepared in Example 8 and Example 9.

[0093] Comparative Example 1

[0094] A preparation method of a uranium-based metal organic framework material, which is basically the same as that of Example 1, with the difference that nitric acid is replaced by hydrochloric acid.

[0095] Comparative Example 2

[0096] A preparation method of a uranium-based metal organic framework material, which is basically the same as that of Example 1, with the difference that nitric acid is replaced by sulfuric acid.

[0097] Comparative Example 3

[0098] A preparation method of a uranium-based metal organic framework material, which is basically the same as that of Example 1, with the difference that nitric acid is replaced by trifluoroacetic acid (TFA).

[0099] Comparative Example 4

[0100] A preparation method of a uranium-based metal organic framework material, which is basically the same as that of Example 1, with the difference that nitric acid is replaced by acetic acid.

[0101] Comparative Example 5

[0102] A preparation method of a uranium-based metal organic framework material, which is basically the same as that of Example 1, with the difference that nitric acid is replaced by formic acid.

[0103] Comparative Example 6

[0104] A preparation method of a uranium-based metal organic framework material, which is basically the same as that of Example 4, with the difference that 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid is replaced by 1-(4-carboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid.

[0105] Comparative Example 7

[0106] A preparation method of a uranium-based metal organic framework material, which is basically the same as that of Example 7, with the difference that acetonitrile is replaced by tetrahydrofuran (THF).

[0107] None of Comparative Examples 1-7 has yellow crystals precipitated, proving that the uranium-based metal organic framework material described in the present application has not been prepared.

[0108] Application Example

[0109] The uranium-based metal-organic framework material prepared in Example 1 was used for X-ray imaging. Specifically, SYLGARD 184 silicone elastomer and a curing agent were thoroughly mixed at a ratio of 10:1, and then 40% of the sieved uranium-based metal-organic framework material powder prepared in Example 1 was added and vigorously stirred. The uniformly mixed solution was then poured onto a vacuum-treated polyethylene terephthalate (PET) substrate and spread evenly using a scraper. Finally, the mixture was heated at 80°C for 24 hours to form a flexible scintillator film.

[0110] X-ray imaging was performed using the aforementioned flexible scintillator film (Moxtek TUB00154-W06). The X-ray source was placed in front of the object being imaged, and the flexible scintillator film was placed close to the back of the object being imaged. Then, a digital camera was used to capture the X-ray image on the flexible scintillator film.

[0111] Test results are as follows Figure 10 As shown, from Figure 10 As can be seen in (a), the flexible scintillator film prepared from the uranium-based metal-organic framework material obtained in Example 1 exhibits good flexibility, is yellow under natural light, and displays a bright green fluorescent film under ultraviolet and X-ray excitation; from Figure 10 As can be seen in (b), using this film to image a resolution card under X-rays can achieve 4 line pairs (lp·mm). -1 (Above) resolution.

[0112] Test Example 1

[0113] The stability of the uranium-based metal-organic framework material prepared in Example 1 for X-ray imaging was tested. The X-ray excitation emission (XEL) spectrum was tested using an X-RAD SmART system with a W Kα radiation source and a NOVA spectrometer (ideaoptics, China). The dose rate was controlled by adjusting the magnitude of the X-ray source current. A spectrometer embedded in a laboratory X-ray source (Bruker D8 advance, with Cu Kα radiation) was used to record the XEL data.

[0114] The normalized comparison of the initial XEL intensity of the uranium-based metal-organic framework material prepared in Example 1 and previous uranium-based MOF materials with increasing 90 Gy X-ray irradiation dose is shown in the figure below. Figure 11 As shown.

[0115] Test Example 2

[0116] The prepared uranium-based metal-organic framework material of Example 1 was tested for its reusability for X-ray imaging by exposing 30 mg of the prepared uranium-based metal-organic framework material of Example 1 to X-ray radiation at 42.3 mGy / s, with a 20-second pause after every 20 seconds of radiation. The peak fluorescence intensity at 513 nm was recorded every second throughout the 30 intermittent radiation cycles.

[0117] The test results, as shown in Figure 12 , prove that the prepared uranium-based metal-organic framework material of the present application has the ability to be reused multiple times.

[0118] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. It should be understood by those skilled in the art that, on the basis of the above description, other different forms of changes or variations can also be made. Here, it is not necessary and also impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A uranium-based metal-organic framework material, characterized in that, The chemical formula of the uranium-based metal-organic framework material is [(UO2)]. 2+ (H2L) 2- )·H2O] n 、[(UO2 2+ )3(HL 3- )2(H2O)3·3H2O] n or [(UO2) 2+ (H2L) 2- )·2H2O] n Where n is a positive integer, and L is an organic ligand with the following structure: 。 2. A method for preparing a uranium-based metal-organic framework material, characterized in that, Includes the following steps: At 80-140 °C, aromatic tetracarboxylic acid and uranyl nitrate are dissolved in a mixed solvent of organic solvent and water. After adding nitric acid, a coordination reaction occurs to obtain the uranium-based metal-organic framework material. The organic solvent is selected from acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and N,N-diethylformamide. The aromatic tetracarboxylic acid is 1-(3,5-dicarboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid.

3. The preparation method according to claim 2, characterized in that, The molar ratio of the aromatic tetracarboxylic acid to uranyl nitrate is (0.5-2):

1.

4. The preparation method according to claim 2, characterized in that, The volume ratio of the organic solvent to water is (0.5-5):(1.5-6).

5. The preparation method according to claim 2, characterized in that, The volume ratio of the organic solvent to nitric acid is (0.5-5):(0.02-0.7).

6. The preparation method according to claim 2, characterized in that, At 100-140 °C, aromatic tetracarboxylic acid and uranyl nitrate are dissolved in a mixed solvent of organic solvent and water. After adding nitric acid, the volume ratio of the organic solvent, water and nitric acid is (3-5):(1.5-3):(0.14-0.7). After a coordination reaction takes place for 2-7 days, the uranium-based metal-organic framework material is obtained.

7. The preparation method according to claim 2, characterized in that, At 80-110 °C, aromatic tetracarboxylic acid and uranyl nitrate are dissolved in a mixed solvent of organic solvent and water. After adding nitric acid, the volume ratio of the organic solvent, water and nitric acid is (0.5-2):(3-6):(0.02-0.1). After a coordination reaction takes place for 4-10 days, the uranium-based metal-organic framework material is obtained.

8. The preparation method according to claim 2, characterized in that, At 80-100 °C, aromatic tetracarboxylic acid and uranyl nitrate are dissolved in a mixed solvent of organic solvent and water. After adding nitric acid, the volume ratio of the organic solvent, water and nitric acid is (0.5-2):(3-6):(0.12-0.4). After a coordination reaction takes place for 7-14 days, the uranium-based metal-organic framework material is obtained.

9. The application of the uranium-based metal-organic framework material according to claim 1 or the uranium-based metal-organic framework material prepared by the method according to any one of claims 2-8 in the preparation of X-ray imaging reagents.

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