A pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material, its preparation method and application

Abstract

This invention relates to the field of luminescent crystal materials technology, and proposes a pyrazole-based two-dimensional Cu(I)-MOF luminescent crystal material, its preparation method, and its applications. The preparation method of the pyrazole-based two-dimensional Cu(I)-MOF luminescent crystal material includes the following steps: S1, placing copper nitrate and pyrazole in a reaction vessel, then adding an organic solvent and deionized water, and stirring until dissolved; S2, heating the mixture from step S1 to 100°C, reacting for 18-24 hours, cooling, washing with an organic solvent, and drying to obtain the Cu(I)-MOF luminescent crystal material. This invention uses low-toxicity copper nitrate containing 2.5 water ions and the organic chromophore pyrazole ligand as raw materials to synthesize a nearly perfect 1:1 coordinated and two-dimensionally layered Cu(I)-MOF. The preparation method is simple and exhibits excellent luminescent properties, with a quantum yield of 99.8%.

Description

Technical Field

[0001] This invention relates to the field of crystal luminescent materials technology, and in particular to a pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material, its preparation method, and its application. Background Technology

[0002] With the rapid development of crystal engineering, the selection and design of ligands have attracted much attention. Ligands not only provide coordination ability but can also influence the entire network and topology by changing the coordination orientation. Pyrazole ligands have attracted much attention due to their multifunctionality and stability. Pyrazole is a five-membered aromatic heterocycle containing two adjacent nitrogen atoms, with two key characteristics: first, the hydrogen on the nitrogen atom can be easily removed to form an anion, enhancing the affinity for metal ions; second, dehydropyrazole, as a 1,2-external bidentate ligand, has a strong bridging ability. By adjusting the electronic and stereo characteristics of the substituents on the pyrazole ring, its coordination behavior can be regulated. This has led to widespread research interest in organometallic chemistry for pyrazole ligand complexes with transition metals, especially low coordination number copper(I) complexes.

[0003] The structures of existing pyrazole-containing complexes can be broadly categorized into the following types: (S1) Complexes where pyrazole does not undergo dehydrogenation to act as a monodentate ligand; in these complexes, pyrazole functions as a pyridine ligand. (S2) Single-bridged pyrazole complexes; this is a well-studied class of pyrazole systems. Depending on the coordination configuration of the central metal atom, the position of substituents on the pyrazole ring, and the reaction conditions, various nucleus numbers and configurations, including homonuclear and heteronuclear pyrazole complexes, can be formed. Among these complexes, the linear coordination of pyrazole with a +1 valence d-type pyrazole ring is the most studied. 10 Polynuclear neutral complexes formed from metal (Cu) [Cu(pz)] n These complexes typically form oligomers of pyrazole mononuclear and polynuclear copper clusters, or coordination polymers with pyrazole polynuclear copper clusters (dianuclear, trinuclear, and hexanuclear structural units) as secondary building blocks.

[0004] Christopher J. Ziegler et al. utilized pyrazole ligands and two bromine atoms to form tetrahedral mononuclear oligomers with copper atoms; in [Cu(Htmpz)4(ClO4)2], the copper atom is hexacoordinated, coordinating with the nitrogen atom of four ligands and the oxygen atoms of two perchlorate ions, forming a distorted octahedral structure. Pyrazole ligands connecting two metal atoms easily form binuclear structural units; sometimes halogen atoms and carboxylate ions simultaneously participate in bridging, often yielding oligomers and one-dimensional chain structures. Bu Xianhe et al. reacted monopyridylpyrazole with copper salts to obtain dinuclear units, which were then stacked into one-dimensional chain polymers through hydrogen bonding. Pyrazole trinuclear metal unit complexes are the most common, easy to synthesize, and have good properties. The structural types of trinuclear units are roughly as follows: coplanar M3(Pz)3, non-coplanar M3(Pz)6, and M3(Pz)3 bridged by halide or acid ion ions, etc. These complexes include numerous oligomers and some coordination polymers linked to copper halide clusters. For pyrazole complexes with higher nucleus numbers, the structures are mostly saddle-shaped, polyhedral, cage-like, or crown-shaped.

[0005] In summary, single-crystal growth remains a challenging problem for metal pyrazole coordination polymers, especially monovalent copper coordination polymers. Compared to other single-crystal synthesis methods (Angew. Chem. Int. Ed., 2021, 60, 2534–2540.) (J. Am. Chem. Soc. 1994, 116, 7668–7676.), the cubic Cu(I)-MOF crystal with a two-dimensional layered structure synthesized in this invention is relatively greener, simpler, and less expensive. It achieves perfect 1:1 coordination, and the two-dimensional Cu-MOF has a near 100% photon yield. With the help of a film-forming solution, it also exhibits excellent performance as a device-forming film material in X-ray scanning imaging. Summary of the Invention

[0006] In view of this, the present invention proposes a method for preparing and applying a pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material with high quantum yield.

[0007] The technical solution of the present invention is achieved as follows: In a first aspect, the present invention provides a method for preparing a pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material, comprising the following steps:

[0008] S1, place copper nitrate and pyrazole in a reaction vessel, then add organic solvent and deionized water, and stir until dissolved;

[0009] S2. Heat the mixture from step S1 to 100°C, react for 18-24 hours, then cool, wash with an organic solvent, and dry to obtain Cu(I)-MOF crystal luminescent material.

[0010] Based on the above technical solutions, preferably, the copper nitrate is Cu(NO3)2·2.5H2O, and the molar ratio of copper nitrate to pyrazole is 1.3~2:1.7~2.5.

[0011] Based on the above technical solutions, preferably, in step S2, the temperature is increased to 100°C at a rate of 1-5°C / min.

[0012] Based on the above technical solutions, preferably, the organic solvents in steps S1 and S2 are N,N-dimethylformamide and anhydrous ethanol.

[0013] Based on the above technical solutions, preferably, the stirring time in step S1 is 5 to 10 minutes and the stirring speed is 300 to 800 rpm.

[0014] Secondly, the present invention provides a pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material, which is prepared by the above-described preparation method.

[0015] Thirdly, the present invention provides an application of pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material in the preparation of Cu(I)-MOF@PMMA scintillator film material.

[0016] Based on the above technical solutions, preferably, the preparation method of the MOF@PMMA scintillator film material includes the following steps:

[0017] S1, pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material and polymethyl methacrylate are dispersed in toluene solution to obtain a precursor turbid liquid. Then, the precursor turbid liquid is dropped onto a glass substrate and spin-coated to form a precursor film.

[0018] S2, the precursor film is placed in an oven for the first annealing, and then the annealed cured film is peeled off from the glass substrate and subjected to a second annealing to obtain the MOF@PMMA scintillator film material.

[0019] Based on the above technical solutions, the preferred mass ratio of pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material to polymethyl methacrylate is 1-2:10-20.

[0020] Based on the above technical solutions, preferably, the first annealing temperature is 40-60℃ and the time is 10 min; the second annealing temperature is 70-90℃ and the time is 5 min.

[0021] The pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material, its preparation method, and its application, as described in this invention, have the following advantages over existing technologies:

[0022] (1) This invention uses inexpensive, readily available, and low-toxic copper nitrate containing 2.5 water molecules and organic chromophore pyrazole ligands as raw materials to synthesize a nearly perfect 1:1 coordinated and two-dimensionally layered Cu(I)-MOF. Its preparation process reduces the cost of crystal synthesis, the preparation method is simple, the product is readily available, the synthesis process does not involve highly polluting or toxic chemical products or intermediates, it is environmentally friendly, the reaction conditions are mild and controllable, and it can be produced in large quantities and continuously.

[0023] (2) The complex created in this invention not only exhibits excellent luminescent properties, including high intensity, high stability, and an astonishing quantum yield of 99.8%, but also has the potential to significantly reduce energy loss in the application of large-area photoluminescence and electroluminescence devices. A major highlight of this material is its relatively broad excitation spectrum and narrow and symmetrical emission spectrum. This means that the complex can be effectively excited over a wide spectral range. As long as the energy of the excitation light exceeds a certain threshold, it can be triggered to emit light. Regardless of the wavelength of the excitation light, its emission spectrum remains fixed and concentrated. This characteristic provides great flexibility and efficiency for the application of the complex in various optoelectronic devices.

[0024] (3) The Cu(I)-MOF crystal luminescent material developed in this invention, when combined with polymethyl methacrylate (PMMA) to form a hybrid matrix film, can emit fluorescence pulses under X-ray irradiation. Therefore, this luminescent material is cleverly designed and used as a scintillator, closely integrated with an electro-conversion array and advanced electronic systems to form a high-performance X-ray detector. This innovative design enables the detector to achieve precise X-ray detection under appropriate technical conditions. Therefore, it demonstrates enormous application potential in X-ray scanning imaging technology, providing strong technical support for multiple fields such as medical diagnosis, security inspection, materials science, and industrial testing. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0026] Figure 1 Here is a physical image of the Cu(I)-MOF crystal luminescent material;

[0027] Figure 2 This is a photograph of a Cu(I)-MOF@PMMA functionally hybrid matrix membrane.

[0028] Figure 3The image shows the SEM morphology of the Cu(I)-MOF crystalline luminescent material from Example 1.

[0029] Figure 4 This is a SEM image of the cross-sectional morphology of the Cu(I)-MOF crystal luminescent material in Example 1.

[0030] Figure 5 The image shows the XRD pattern of the Cu(I)-MOF crystal luminescent material from Example 1.

[0031] Figure 6 This is a single-crystal structure diagram of the Cu(I)-MOF luminescent material of Example 1;

[0032] Figure 7 The image shows the TGA test results of the Cu(I)-MOF crystal luminescent material from Example 1.

[0033] Figure 8 The solid-state ultraviolet absorption spectrum of the Cu(I)-MOF crystal luminescent material in Example 1 is shown below.

[0034] Figure 9 The photoluminescence spectrum of the Cu(I)-MOF crystal luminescent material in Example 1 is shown below.

[0035] Figure 10 The quantum yield diagram of the Cu(I)-MOF crystal luminescent material prepared in Example 1 is shown.

[0036] Figure 11 , 12 13 shows the actual photographs and X-ray images of the MOF@PMMA scintillator film materials prepared in Examples 4-6 before and after X-ray imaging; Figure 11-12 In the image, A is the actual object, and B and C are X-ray images. Figure 13 In the diagram, A and C are actual images, while B and D are X-ray images.

[0037] Figure 14 MOF@PMMA scintillator thin film for Cu(I)-MOF crystal luminescent material, imaged using a line-pair card at standard X-ray resolution. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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.

[0039] The copper nitrate used in this invention contains 2.5 molecules of copper(II) crystal water (Cu(NO3)2·2.5H2O), the purity of pyrazole is 99.98%, the resistivity of deionized water is 0.5 MΩ*cm (25℃), and anhydrous ethanol is an analytical grade reagent.

[0040] Example 1

[0041] The preparation method of the pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material in this example includes the following steps:

[0042] S1, place 0.4g Cu(NO3)2·2.5H2O and 0.136g pyrazole (molar ratio 0.861:1, i.e. 1.464:1.7) into the inner liner of the reactor;

[0043] S2, add 13.2 mL of N,N-dimethylformamide, 10 mL of deionized water and 13.2 mL of anhydrous ethanol to the inner liner of the reaction vessel in step S1, and stir at 500 rpm for 8 min at room temperature until completely dissolved to obtain solution A;

[0044] S3, the reaction vessel containing solution A from step S2 is completely sealed and placed in a forced-air drying oven, heated to 100℃ at a rate of 2℃ / min, kept at 100℃ for 20h, and then naturally cooled to obtain a two-dimensional Cu(I)-MOF crystal luminescent material.

[0045] S4. Take out the material obtained in step S3 using a dropper and transfer it to a 100mL beaker. Pour N,N-dimethylformamide into the beaker twice, each time using 30mL, to wash away trace amounts of unreacted pyrazole and poorly crystallized luminescent material. Then pour anhydrous ethanol three times, each time using 50mL, to wash further remove unreacted monomers and the N,N-dimethylformamide used in the washing process, facilitating the drying and use of the material. After drying, a two-dimensional Cu(I)-MOF luminescent material is obtained.

[0046] Tests showed that the photoluminescent quantum yield of the two-dimensional Cu(I)-MOF crystal luminescent material prepared in this embodiment was 99.86%, close to 100%.

[0047] Example 2

[0048] The preparation method of the pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material in this example includes the following steps:

[0049] S1. Place 0.4g Cu(NO3)2·2.5H2O and 0.2g pyrazole (molar ratio 0.59:1, i.e. 1.3:2.2) into the inner liner of the reactor.

[0050] S2. Add 13.2 mL of N,N-dimethylformamide, 10 mL of deionized water and 13.2 mL of anhydrous ethanol to the inner liner of the reaction vessel in step S1 in sequence, and stir at 800 rpm for 5 min at room temperature until completely dissolved to obtain solution A;

[0051] S3. The reaction vessel containing solution A from step S2 is completely sealed and placed in a forced-air drying oven. The temperature is increased to 100°C at a rate of 1°C / min, and kept at 100°C for 18 hours, followed by natural cooling.

[0052] S4. Take out the material obtained in step S3 using a dropper and transfer it to a 100mL beaker. Pour N,N-dimethylformamide into the beaker twice, each time using 30mL, to wash away trace amounts of unreacted pyrazole and poorly crystallized luminescent material. Then pour anhydrous ethanol three times, each time using 50mL, to wash further remove unreacted monomers and the N,N-dimethylformamide used in the washing process, facilitating the drying and use of the material. After drying, a two-dimensional Cu(I)-MOF luminescent material is obtained.

[0053] The photoluminescence quantum yield of the two-dimensional Cu(I)-MOF crystal luminescent material prepared in this embodiment was tested to be 99.75%.

[0054] Example 3

[0055] The preparation method of the pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material in this example includes the following steps:

[0056] S1. Place 0.4g Cu(NO3)2·2.5H2O and 0.146g pyrazole (molar ratio 2:2.5) into the inner liner of the reactor;

[0057] S2. Add 13.2 mL of N,N-dimethylformamide, 10 mL of deionized water and 13.2 mL of anhydrous ethanol to the inner liner of the reaction vessel in step S1 in sequence, and stir at 300 rpm for 10 min at room temperature until completely dissolved to obtain solution A;

[0058] S3. The reaction vessel containing solution A from step S2 is completely sealed and placed in a forced-air drying oven. The temperature is increased to 100°C at a rate of 5°C / min, and kept at 100°C for 24 hours, followed by natural cooling.

[0059] S4. Take out the material obtained in step S3 using a dropper and transfer it to a 100mL beaker. Pour N,N-dimethylformamide into the beaker twice, each time using 30mL, to wash away trace amounts of unreacted pyrazole and poorly crystallized luminescent material. Then pour anhydrous ethanol three times, each time using 50mL, to wash further remove unreacted monomers and the N,N-dimethylformamide used in the washing process, facilitating the drying and use of the material. After drying, a two-dimensional Cu(I)-MOF luminescent material is obtained.

[0060] The photoluminescent material of the two-dimensional Cu(I)-MOF crystal prepared in this embodiment has a photoluminescence yield of 99.81% according to the test results.

[0061] Table 1. Crystallographic data of the Cu(I)-MOF luminescent material prepared in Example 1

[0062]

[0063]

[0064] Comparative Example 1

[0065] The difference between Comparative Example 1 and Example 1 is the amount of Cu(NO3)2·2.5H2O and pyrazole used, which are 0.465g Cu(NO3)2·2.5H2O and 0.272g pyrazole (molar ratio 0.5:1), respectively. The rest is the same as in Example 1.

[0066] After drying, a flocculent material was obtained. The photon yield of the material obtained in Comparative Example 1 was tested and found to be 90%.

[0067] Comparative Example 2

[0068] The difference between Comparative Example 2 and Example 1 is the amount of Cu(NO3)2·2.5H2O and pyrazole used, which are 0.93g Cu(NO3)2·2.5H2O and 0.136g pyrazole (molar ratio 2:1), respectively. The rest is the same as in Example 1.

[0069] After drying, a flocculent material was obtained. The photon yield of the material obtained in Comparative Example 2 was tested to be 86%.

[0070] Comparative Example 3

[0071] The difference between Comparative Example 3 and Example 1 is that the amounts of Cu(NO3)2·2.5H2O and pyrazole are different, namely 0.465g Cu(NO3)2·2.5H2O and 0.68g pyrazole (molar ratio 0.2:1), and the rest is the same as Example 1.

[0072] No luminescent material was obtained after drying. According to the ultraviolet analyzer, the material obtained in Comparative Example 3 showed very weak fluorescence characteristics under ultraviolet light irradiation at wavelengths of 254nm and 365nm.

[0073] Comparative Example 4

[0074] The difference between Comparative Example 4 and Example 1 is the amount of Cu(NO3)2·2.5H2O and pyrazole used, which are 2.326g Cu(NO3)2·2.5H2O and 0.136g pyrazole (molar ratio 5:1), respectively. The rest is the same as in Example 1.

[0075] No crystalline luminescent material was obtained after drying. According to the ultraviolet analyzer, the material obtained in Comparative Example 4 showed very weak fluorescence characteristics under ultraviolet light irradiation at wavelengths of 254nm and 365nm.

[0076] Comparative Example 5

[0077] The difference between Comparative Example 5 and Example 1 is the amount of Cu(NO3)2·2.5H2O and pyrazole used, which are 0.465g Cu(NO3)2·2.5H2O and 1.36g pyrazole (molar ratio 0.1:1), respectively. The rest is the same as in Example 1.

[0078] After drying, needle-shaped luminescent materials were obtained. The photon yield of the material obtained in Comparative Example 5 was 46%.

[0079] Comparative Example 6

[0080] The difference between Comparative Example 6 and Example 1 is the amount of Cu(NO3)2·2.5H2O and pyrazole used, which are 4.65g Cu(NO3)2·2.5H2O and 0.126g pyrazole (molar ratio 10:1), respectively. The rest is the same as in Example 1.

[0081] After drying, needle-shaped luminescent materials were obtained. The photon yield of the material obtained in Comparative Example 6 was 52% after testing.

[0082] Comparative Example 7

[0083] Comparative Example 7 provides a two-dimensional Zn-MOF crystal luminescent material and its preparation method, using 0.126g pyrazole and 0.35g zinc nitrate (II) as raw materials, with the remaining steps being the same as in Example 1.

[0084] No crystalline luminescent material was obtained after drying. According to the ultraviolet analyzer, the material obtained in Comparative Example 7 showed very weak fluorescence characteristics under ultraviolet light irradiation at wavelengths of 254nm and 365nm.

[0085] Comparative Example 8

[0086] Comparative Example 8 provides a two-dimensional Co-MOF crystal luminescent material and its preparation method, using 0.126g pyrazole and 0.34g cobalt(II) nitrate as raw materials, with the remaining steps being the same as in Example 1.

[0087] No luminescent material was obtained after drying. Simple tests using an ultraviolet analyzer showed that the material obtained in Comparative Example 8 had no fluorescent properties under ultraviolet light irradiation at wavelengths of 254 nm and 365 nm.

[0088] Comparative Example 9

[0089] Comparative Example 9 provides a two-dimensional Fe-MOF crystal luminescent material and its preparation method, using 0.126g pyrazole and 0.34g ferric nitrate (II) as raw materials, with the remaining steps being the same as in Example 1.

[0090] No luminescent crystalline material was obtained after drying. Simple tests using an ultraviolet analyzer showed that the material obtained in Comparative Example 9 did not exhibit fluorescence under ultraviolet light irradiation at wavelengths of 254 nm and 365 nm.

[0091] Comparative Example 10

[0092] Comparative Example 10 provides a two-dimensional Cu(I)-MOF crystal luminescent material and its preparation method. The raw materials are 0.19g tetrachloropyrazole and 0.4g Cu(NO3)2·2.5H2O, and the remaining steps are the same as in Example 1.

[0093] After drying, a crystalline luminescent material was obtained. After simple testing with an ultraviolet analyzer, the material obtained in Comparative Example 10 showed no fluorescence under ultraviolet light irradiation at wavelengths of 254 nm and 365 nm.

[0094] Comparative Example 11

[0095] Comparative Example 11 provides a two-dimensional Cu(I)-MOF crystal luminescent material and its preparation method. The raw materials are 0.36g tetraiodopyrazole and 0.4g Cu(NO3)2·2.5H2O, and the remaining steps are the same as in Example 1.

[0096] After drying, a crystalline luminescent material was obtained. After simple testing with an ultraviolet analyzer, the material obtained in Comparative Example 11 showed no fluorescence under ultraviolet light irradiation at wavelengths of 254 nm and 365 nm.

[0097] After testing Examples 1-3, only Example 1 is a two-dimensional Cu-MOF crystal luminescent material with a 1:1 coordination structure, and its photon yield is close to 100%.

[0098] Comparative Examples 1-2 show that when the molar ratio of pyrazole to copper(II) nitrate containing 2.5 molecules of water of crystallization is 1:2 or 2:1, flocculent crystals are formed. Even with a slightly higher concentration of ligands, they can still fully coordinate with the reactants and promote the reaction. In this case, although the number of ligands is slightly higher, it does not exceed the critical point, therefore it does not significantly inhibit the reaction but continues to promote material formation. The reaction kinetics and the function of the ligands determine that ligand variations within a certain range can be absorbed by the system and will not hinder the formation of the target product.

[0099] As shown in Comparative Examples 3-4, when the molar ratio of pyrazole to copper(II) containing 2.5 molecules of water of crystallization was 1:5 or 5:1, no crystals were ultimately formed. Excessive ligand concentration deviates from the ideal equilibrium state, making ligand dissociation in the reaction system difficult, thus affecting the reaction and product formation. More ligands also form a larger steric barrier around the metal center, hindering other reactants from approaching the active site, thereby reducing the reaction rate and product yield.

[0100] Comparative Examples 5-6 show that when the molar ratio of pyrazole to copper(II) nitrate containing 2.5 molecules of water of crystallization is 1:10 or 10:1, needle-like materials are formed. Increasing the ligand makes the side reactions more significant, thus generating materials different from the target product. It also alters the crystallization behavior in the system, leading to the formation of more crystals or different crystal forms.

[0101] As shown in Comparative Example 7, the obtained material did not yield crystals, but it exhibited weak fluorescence. Zn2 + When Zn2 ​​binds to pyrazole ligands to form a complex, + Ions influence the electronic structure of pyrazole. This coordination can lead to rearrangement of the π-electron system or changes in energy levels of the pyrazole ligands, making transitions between molecular orbitals more likely, especially radiative transitions from the excited state to the ground state, thus producing fluorescence. Cu + Coordination chemistry can significantly affect the electronic structure of ligands. By forming coordinate bonds with pyrazole, it polarizes the electron cloud of the ligand, causing changes in the energy level structure of the ligand, thereby enhancing fluorescence properties.

[0102] Comparative Examples 8-9 show that this method cannot synthesize the corresponding crystalline luminescent materials from Co and Fe, and the obtained materials lack fluorescence properties. Comparative Examples 10-11 show that although the materials obtained using tetraiodopyrazole and tetrachloropyrazole are crystalline, they lack fluorescence properties under ultraviolet light irradiation at wavelengths of 254 nm and 365 nm. Tetraiodopyrazole and tetrachloropyrazole contain heavy atoms (iodine and chlorine), which can enhance spin-orbit coupling, thereby increasing the possibility of intersystem crossing (nonradiative transition from singlet to triplet states). This means that more excited-state energy is released through nonradiative pathways (such as thermal energy) rather than through luminescence.

[0103] Figure 1 The Cu(I)-MOF crystal luminescent material prepared in Example 1 shows obvious fluorescence under ultraviolet light irradiation, as observed in the figure.

[0104] Figure 2 The Cu(I)-MOF crystal and PMMA mixed matrix film material prepared in Example 1 is shown in the figure. The prepared film material has a regular three-dimensional cubic shape, and the Cu(I)-MOF crystal luminescent material is uniformly mixed in PMMA.

[0105] Figure 3 , 4 The image shows the SEM morphology of the Cu(I)-MOF crystal luminescent material prepared in Example 1. As can be seen from the image, the surface and cross-sectional morphology of the prepared Cu(I)-MOF crystal luminescent material are uniform, dense, and stacked in layers.

[0106] Figure 5 The XRD pattern of the Cu(I)-MOF crystalline luminescent material prepared in Example 1 was compared with the XRD pattern simulated in the CIF file. The results showed that the test results were consistent with the fitting results.

[0107] Figure 6 The figure shows the single-crystal structure of the Cu(I)-MOF luminescent material prepared in Example 1. As can be seen from the figure, the material is a cubic crystal structure formed by the 1:1 coordination of Cu(I) and pyrazole groups.

[0108] Figure 7 The image shows the TG test results of the Cu(I)-MOF crystal luminescent material prepared in Example 1. Analysis of the image shows that the mass of the material remains basically unchanged at temperatures below 300°C, while the mass decreases by about 40% at 600°C, indicating that the material has excellent thermal stability.

[0109] Figure 8 The image shows the solid-state ultraviolet absorption spectrum of the Cu(I)-MOF crystal luminescent material prepared in Example 1. Analysis of the image shows that the material exhibits excellent light absorption performance under ultraviolet light in the range of 200 nm to 800 nm.

[0110] Figure 9 The photoluminescence spectrum of the Cu(I)-MOF crystal luminescent material prepared in Example 1 is shown in the figure. Analysis of the figure shows that when the excitation light source wavelength is 235 nm, the material emits the highest light intensity at a wavelength of 555 nm.

[0111] Figure 10The figure shows the quantum yield of the Cu(I)-MOF crystal luminescent material prepared in Example 1. Analysis of the figure shows that the photoluminescence quantum yield of the material at 325 nm under a 310 nm excitation light source is close to 100%.

[0112] Example 4

[0113] Example 4 provides a method for preparing Cu(I)-MOF@PMMA scintillator film material for X-ray scanning imaging, as follows:

[0114] S1, 1.5g of the two-dimensional Cu-MOF crystal luminescent material prepared in Example 1 and 20g of PMMA raw material were dispersed in a toluene solution, and then the PMMA was dissolved in the toluene solvent to obtain a uniformly mixed precursor turbid liquid.

[0115] S2, drop the precursor turbid liquid onto the glass substrate and start rapidly rotating the coating until a precursor film is formed.

[0116] S3, the precursor film was placed in a constant temperature oven at 50°C for a first annealing of 10 minutes, and then the annealed and cured film was peeled off from the glass substrate. Then, the peeled film was placed in a glass dish and placed in a constant temperature oven for a second annealing of 80°C for 5 minutes to obtain the two-dimensional Cu-MOF scintillator film material.

[0117] Example 5

[0118] Compared with Example 4, Example 5 uses 1g of two-dimensional Cu-MOF crystal luminescent material, 15g of PMMA, and the first annealing temperature is 40℃ and the second annealing temperature is 70℃.

[0119] Example 6

[0120] Compared with Example 4, Example 6 uses 2g of two-dimensional Cu-MOF crystal luminescent material, 10g of PMMA, and the first annealing temperature is 60℃ and the second annealing temperature is 90℃.

[0121] Figure 11 , 12 Figures 1 and 13 show photographs and X-ray images of the Cu(I)-MOF@PMMA scintillator film materials prepared in Examples 4-6 before and after X-ray imaging. As can be seen from the figures, the images formed by the Cu(I)MOF@PMMA thin film scintillator have high clarity and have great potential value in X-ray scanning imaging.

[0122] Figure 14The Cu(I)-MOF@PMMA scintillator film prepared in Example 4 was photographed using a line-pair card with standard X-ray resolution. Analysis of the figure shows that this material, combined with PMMA-assisted film formation, has a very high spatial resolution in X-ray scanning imaging, reaching 15.5-17.5.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material, characterized in that: Includes the following steps: S1, place copper nitrate and pyrazole in a reaction vessel, then add organic solvent and deionized water, and stir until dissolved; S2, heat the mixture from step S1 to 100℃, react for 18-24 h, cool, wash with organic solvent, and dry to obtain Cu(I)-MOF crystal luminescent material; The copper nitrate is Cu(NO3)2·2.5H2O, and the molar ratio of copper nitrate to pyrazole is 1.3~2:1.7~2.

5.

2. The method for preparing a pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material as described in claim 1, characterized in that: During step S2, the temperature is increased to 100°C at a rate of 1~5°C / min.

3. The method for preparing a pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material as described in claim 1, characterized in that: The organic solvents mentioned in steps S1 and S2 are N,N-dimethylformamide and anhydrous ethanol.

4. The method for preparing a pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material as described in claim 1, characterized in that: In step S1, the stirring time is 5-10 min and the stirring speed is 300-800 rpm.

5. A pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 4.

6. The application of the pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material as described in claim 5 in the preparation of Cu(I)-MOF@PMMA scintillator film material.

7. The application of the pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material as described in claim 6 in the preparation of Cu(I)-MOF@PMMA scintillator film material, characterized in that: The preparation method of the Cu(I)-MOF@PMMA scintillator film material includes the following steps: S1, pyrazolium-based two-dimensional Cu(I)-MOF crystal luminescent material and polymethyl methacrylate are dispersed in toluene solution to obtain a precursor turbid liquid. Then, the precursor turbid liquid is dropped onto a glass substrate and spin-coated to form a precursor film. S2, the precursor film is placed in an oven for the first annealing, and then the annealed cured film is peeled off from the glass substrate and subjected to a second annealing to obtain Cu(I)-MOF@PMMA scintillator film material.

8. The application of the pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material as described in claim 7 in the preparation of Cu(I)-MOF@PMMA scintillator film material, characterized in that: Pyrazolyl two-dimensional Cu(I)-MOF crystal luminescent material: the mass ratio of polymethyl methacrylate is 1~2:10~20.

9. The application of the pyrazole-based two-dimensional Cu(I)-MOF crystal luminescent material as described in claim 7 in the preparation of Cu(I)-MOF@PMMA scintillator film material, characterized in that: The first annealing temperature is 40~60℃ and the time is 10 min; the second annealing temperature is 70~90℃ and the time is 5 min.

Images