Pyrazolyl-based cyclic trinuclear complex, synthesis method thereof and application of pyrazolyl-based cyclic trinuclear complex in field of X-ray imaging

Abstract

The embodiment of the invention discloses a pyrazole-based fund cyclic trinuclear complex, a synthesis method thereof and application of the pyrazole-based fund cyclic trinuclear complex in the field of X-ray imaging, relates to the technical field of metal-organic complex luminescent materials, and aims to overcome the defects of existing scintillator materials in practical application. According to the application of the pyrazole-based gold ring trinuclear complex in the field of X-ray imaging, the pyrazole-based gold ring trinuclear complex is used for preparing a scintillation screen material for X-ray imaging; the general structural formula of the pyrazolyl-based cyclic trinuclear complex is shown as follows: in the formula, R1, R2 and R3 are all substituent groups; the substituent group comprises at least one of methyl, ethyl, trifluoromethyl, carboxylic acid ethyl ester group, chlorine atom, bromine atom or iodine atom.

Description

Technical Field

[0001] This application relates to the field of metal-organic complex luminescent materials technology, specifically to a pyrazole quaternary trinuclear complex, its synthesis method, and its application in the field of X-ray imaging. Background Technology

[0002] X-rays, with their excellent penetrating power, have become a core detection method in fields such as medical imaging diagnosis, industrial non-destructive testing, and public safety inspection. As a key functional material in X-ray detectors, scintillators have the ability to efficiently convert high-energy X-ray photons into ultraviolet / visible / near-infrared light signals, which can then be detected by conventional photodetectors. Compared to complex direct detectors that require direct X-ray-electron conversion, scintillator-based indirect detection technology demonstrates greater practical value.

[0003] Current scintillator materials still face significant challenges: the preparation of traditional inorganic scintillators relies on high-temperature processes (typically exceeding 1000℃), and most contain toxic heavy metals such as lead and cadmium, resulting in high production costs. On the other hand, some novel organic-inorganic hybrid scintillators with high light yields suffer from complex synthesis steps and cumbersome preparation processes. From a luminescence mechanism perspective, these materials often struggle to simultaneously achieve high light yield and fast scintillation response, creating an inherent contradiction between the two. These factors collectively restrict the application and widespread adoption of novel organic-inorganic hybrid scintillators in practical scenarios. Summary of the Invention

[0004] The main objective of this application is to provide a pyrazole quaternary trinuclear complex, its synthesis method, and its application in the field of X-ray imaging, aiming to address the shortcomings of existing scintillator materials in practical applications.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In a first aspect, embodiments of this application provide an application of a pyrazole quaternary trinuclear complex in the field of X-ray imaging, wherein the pyrazole quaternary trinuclear complex is used to prepare a scintillation screen material for X-ray imaging; The general structural formula of the pyrazole cyclotrinuclear complex is shown below: ; In the formula, R1, R2 and R3 are all substituents; the substituents include at least one of methyl, ethyl, trifluoromethyl, ethyl carboxylate, chlorine atom, or bromine atom or iodine atom.

[0006] As some optional embodiments of this application, the pyrazole quaternary trinuclear complex is used as a scintillator to prepare scintillator materials for simulated X-ray dynamic vascular imaging or security detection imaging.

[0007] As some optional embodiments of this application, the flicker screen material is prepared by the following steps: Polyvinylidene fluoride-hexafluoropropylene and pyrazole tricyclic complex were mixed and added to N,N-dimethylformamide. The mixture was stirred evenly at a preset temperature and then electrospun to obtain a pyrazole tricyclic complex scintillator screen.

[0008] As some optional embodiments of this application, the mixing mass ratio of the polyvinylidene fluoride-hexafluoropropylene to the pyrazole quaternary trinuclear complex (hereinafter referred to as AuCTC) is 1-10:1.

[0009] As some optional embodiments of this application, the mixing volume ratio of the N,N-dimethylformamide to the polyvinylidene fluoride-hexafluoropropylene is 1-5:1.

[0010] As some optional embodiments of this application, the preset temperature is 35°C and the stirring time is 15 min-30 min.

[0011] As some optional embodiments of this application, the pyrazole quaternary trinuclear complex as a scintillator has a light yield of 28528 photons / MeV and a photoluminescence quantum yield of 73.2%.

[0012] Secondly, embodiments of this application also provide a method for synthesizing a pyrazole-based trinuclear complex, comprising the following steps: Dissolve 1 mmol of ligand and 1 mmol of tetrachloroauric acid in a 30 mL:30 mL mixture of ethanol and acetone. Add triethylamine dropwise until a white precipitate forms. Continue stirring for 30 minutes, then filter to obtain a white precipitate. Wash the white precipitate with 10 mL of ethanol and air dry to obtain the final product.

[0013] As some alternative embodiments of this application, the ligand includes one or more of the following: 3,5-dimethyl-1H-pyrazole, 3,5-bis(trifluoromethyl)-1H-pyrazole, 3,5-carboxylic acid diethyl ester-1H-pyrazole, 4-chloropyrazole, and 4-bromopyrazole.

[0014] Thirdly, embodiments of this application also provide a pyrazole-based trinuclear complex, prepared by the method described above.

[0015] Compared to existing technologies, this application proposes a pyrazole quaternary trinuclear complex, its synthesis method, and its application in X-ray imaging. It has significant application value in medical rapid imaging, security inspection, and industrial non-destructive testing. It offers the following advantages: High light output: Some representative AuCTCs have light outputs exceeding 20,000, higher than most commercial scintillators; Simple preparation: one-pot synthesis at room temperature, rapid synthesis in 30 minutes; Unique near-infrared broad peak emission behavior: It has a broad peak emission behavior in the red light and near-infrared regions at around 700nm. Compared with common visible scintillators, it is beneficial to improve detection sensitivity and can also effectively reduce the autofluorescence interference of biological tissues, which has special advantages in the field of biomedical imaging.

[0016] High photoluminescence quantum yield: up to 73.2%; No toxic elements: Gold has better biocompatibility.

[0017] These advantages make AuCTC an ideal candidate material for next-generation high-performance scintillators. Attached Figure Description

[0018] Figure 1 The X-ray powder diffraction patterns of the simulated and synthesized AuCTC involved in the embodiments of this application are shown below. Figure 2 The photoluminescence excitation spectrum and emission spectrum of AuCTC involved in the embodiments of this application are shown below; Figure 3 This is a photoluminescence lifetime decay spectrum of AuCTC involved in the embodiments of this application; Figure 4 This is a photoluminescence quantum yield diagram of AuCTC involved in the embodiments of this application; Figure 5 The diagram shows the absorption coefficient and attenuation efficiency of AuCTC involved in the embodiments of this application; subplot a represents the absorption coefficient diagram; subplot b represents the relationship between attenuation efficiency and thickness; the X-ray radiation is generated by a tungsten metal target with an excitation energy of 10 keV. Figure 6 This is a graph showing the stability evaluation results of the radiative emission intensity of the AuCTC involved in the embodiments of this application; the X-ray dose rate is 23.11 mGy. air / s, lasting 30 minutes; Figure 7 The following are the radioluminescence spectra of AuCTC and commercial scintillator cerium-doped lutetium aluminum garnet (LuAG(Ce)) obtained under the same measurement conditions in the embodiments of this application; X-ray tube parameters: tungsten target, 50kV, 20μA; sample thickness 1mm; Figure 8These are X-ray imaging images based on an AuCTC scintillator screen according to embodiments of this application; wherein, sub-image a represents a bright-field image of a pill encapsulating a metal spring, sub-image b represents a bright-field image of a resolution standard ruler, sub-image c represents an X-ray image of a pill encapsulating a metal spring, and sub-image d represents an X-ray image of a resolution standard ruler.

[0019] Figure 9 This is a dynamic vascular X-ray imaging image based on an AuCTC scintillator screen, which is involved in the embodiments of this application. Detailed Implementation

[0020] It should be made clear that the specific implementation examples described herein are for illustrative purposes only and are not intended to limit this application.

[0021] As mentioned above, X-rays, due to their strong penetrating properties, have become an indispensable technical means in fields such as industrial non-destructive testing (e.g., material defect analysis), public safety inspection, and medical imaging diagnosis. Scintillators, as the core conversion material of X-ray detectors, can convert high-energy X-ray photons into ultraviolet / visible light signals, which can then be detected by conventional photoelectric sensors. Compared to complex direct detectors that require direct "X-ray-electron" conversion, scintillator-based indirect detection technology has more significant practical advantages.

[0022] However, the current scintillator material system has significant drawbacks. Traditional inorganic scintillators rely on high-temperature sintering processes, contain toxic heavy metals such as lead and cadmium, and have high manufacturing costs. On the other hand, novel scintillators often suffer from low light yield, poor environmental stability, complex synthesis processes, high costs, and residual toxic elements, which seriously restrict their industrial application.

[0023] Based on this, this application proposes a series of scintillator materials based on pyrazole-based trinuclear metal-organic complexes and their preparation methods. Compared with existing scintillator materials, the scintillator materials prepared by the method of this application have a high light yield of 28528 photons / MeV and a photoluminescence quantum yield of 73.2%, as well as good irradiation stability and fast scintillation speed, which can be applied to dynamic X-ray imaging. In addition, the preparation method of this application can synthesize the scintillator materials in large quantities at room temperature, without involving toxic heavy metals in the preparation process, and with low production costs. Therefore, the preparation method of this application has significant application value in medical CT and security detection scenarios.

[0024] When scintillator materials are used in scenarios such as medical CT and security inspection, large-area scintillator screen materials are required, which in turn necessitates a large quantity of scintillator materials. Therefore, this application provides a method for the large-scale preparation of pyrazolium-based trinuclear complexes, aiming to develop an efficient, inexpensive, and large-scale method for synthesizing pyrazolium-based cyclic gold trinuclear complexes. The large-scale preparation method includes the following steps: Step S10: Dissolve 1 mmol of ligand and 1 mmol of tetrachloroauric acid in a mixed solvent of 30 mL of ethanol and 30 mL of acetone. After adding a few drops of triethylamine, a white precipitate is immediately formed. After stirring the suspension for 30 minutes, filter out the white precipitate, wash it with 10 mL of ethanol, and air dry it to obtain the white complex product, which is the pyrazole fund trinuclear complex, with a yield of about 70%.

[0025] The general structural formula of the pyrazole cyclotrinuclear complex (also known as the pyrazole cyclotrinuclear complex, both referring to the same substance) is shown below: ; R1, R2, and R3 are all substituents.

[0026] To facilitate understanding by those skilled in the art, the following will list the possible types of substituents: The substituents include at least one of methyl, ethyl, trifluoromethyl, ethyl carboxylate, chlorine, bromine, or iodine.

[0027] Preferably, the pyrazole-based trinuclear complex is COOEtPz-Au, and its structural formula is shown below: ; Preferably, the pyrazole-based trinuclear complex is CF3Pz-Au, and its structural formula is shown below: ; Preferably, the pyrazole-based trinuclear complex is MePz-Au, and its structural formula is shown below: ; Preferably, the pyrazole-based trinuclear complex is BrPz-Au, and its structural formula is shown below: ; Preferably, the pyrazole-based trinuclear complex is ClPz-Au, and its structural formula is shown below: ; The aforementioned AuCTC complexes can be prepared in large quantities using a simple synthetic method that employs only ethanol as a solvent, ensuring ease of operation and environmental friendliness. Under solid-state conditions at room temperature, UV excitation induces bright luminescence in AuCTCs, exhibiting aggregation-induced emission (AIE) properties. The yield using this method is over 70%. The phase purity of these AuCTCs was confirmed by X-ray powder diffraction (PXRD). Figure 1 ).

[0028] Steady-state photoluminescence analysis was used to study the photophysical properties of AuCTC. AuCTC exhibits a broad emission band photoluminescence spectrum in the 650 nm–750 nm range, with its excitation peaks all located below 350 nm (e.g., ...). Figure 2 (As shown).

[0029] like Figure 3 As shown in Table 1, time-resolved photoluminescence (TRPL) analysis revealed that the lifetimes of COOEtPz-Au, CF3Pz-Au, MePz-Au, BrPz-Au, and ClPz-Au were 15.58 μs, 31.63 μs, 16.21 μs, 14.92 μs, and 14.32 μs, respectively.

[0030] In addition, such as Figure 4 As shown in Table 1, the photoluminescence quantum yields (PLQY) of COOEtPz-Au, CF3Pz-Au, MePz-Au, BrPz-Au, and ClPz-Au are 73.9%, 64.7%, 69.68%, 73.2%, and 70.03%, respectively.

[0031] Table 1: ; On the other hand, embodiments of this application also provide imaging applications for the pyrazole-based tricyclic scintillator, specifically, using the pyrazole-based tricyclic scintillator to prepare scintillator screen materials for X-ray imaging. Specifically, this includes: using the pyrazole-based tricyclic scintillator to prepare scintillator screen materials for medical imaging, such as using the pyrazole-based tricyclic scintillator to prepare scintillator screen materials for simulated X-ray dynamic vascular imaging; and, for example, using the pyrazole-based tricyclic scintillator to prepare scintillator screen materials for security detection imaging.

[0032] It should be noted that the flickering screen material is prepared through the following steps: Polyvinylidene fluoride-hexafluoropropylene (PVDF-HFA) and AuCTC are mixed and then added to N,N-dimethylformamide. After stirring evenly at a preset temperature, the mixture is cast onto a silicone mold and air-dried to obtain an AuCTC scintillator screen. Specifically, the mass ratio of PVDF-HFA to AuCTC is approximately 1-10:1; the volume ratio of N,N-dimethylformamide to PVDF-HFA is approximately 1-5:1. The preset temperature is 35°C, and the stirring time is 15-30 minutes.

[0033] The light yield of the pyrazole gyroscope trinuclear scintillator described in this application can reach 28528 photons / MeV, and the photoluminescence quantum yield of the pyrazole gyroscope trinuclear scintillator can reach 73.2%.

[0034] The preparation process and performance testing of the pyrazole-based trinuclear complex described in this application will be described in detail below with reference to specific embodiments: Example 1: Synthesis of AuCTC: COOEtPz-Au, CF3Pz-Au, MePz-Au, BrPz-Au, and ClPz-Au can be synthesized using 3,5-dimethyl-1H-pyrazole, 3,5-bis(trifluoromethyl)-1H-pyrazole, 3,5-carboxylic acid diethyl ester-1H-pyrazole, 4-chloropyrazole, and 4-bromopyrazole as ligands, respectively, according to existing techniques.

[0035] Measurement of X-ray scintillation characteristics: The relationship between total X-ray absorption coefficient and photon energy was obtained from the XCOM database provided by the National Institute of Standards and Technology (NIST). The attenuation efficiency (AE, %) was further calculated using formula (1): Formula (1) Where ρ (g / cm) is the density of the scintillator, d (cm) is the thickness of the scintillator, e is the natural constant, and t (cm) is the thickness of the scintillator. 2 / g) is the total attenuation of the scintillator.

[0036] X-ray photon yield (LY) was measured using a tungsten X-ray tube mounted on a fluorescence spectrometer. LY was determined using a reference method with a commercially available LuAg(Ce) crystal as the standard scintillator. To minimize the effect of thickness, all samples were prepared to a thickness ≥1 mm. Both samples and the standard scintillator were irradiated using an X-ray tube operating at 50 kV and 20 μA. The emitted photons (P...) measured The X-ray attenuation (AE) is quantified and normalized to 100% according to formula (2): (2) Formula (2) Where AE(d) is the attenuation coefficient at the actual thickness when the photon energy is 10 keV (peak energy of the tungsten tube), and P measured P is the peak area corresponding to the RL spectrum of the scintillator. normalized This is the corrected peak area. For example... Figure 5 As shown, the attenuation coefficients of COOEtPz-Au, CF3Pz-Au, MePz-Au, BrPz-Au, and ClPz-Au are calculated to be 100%, 100%, 100%, 100%, 100%, and 100%, respectively.

[0037] Light yield of the sample ( It can be calculated using formula (3): Formula (3) Among them, the LY of LuAG(Ce) is 25000 photons / MeV.

[0038] For X-ray imaging, a scintillation screen was prepared by dissolving 500 mg of polyvinylidene fluoride-hexafluoropropylene in approximately 10 mL with stirring at 35°C. After adding 500 mg of MePz-Au, the mixture was stirred to form a homogeneous suspension, poured into a silicon mold, and air-dried. X-ray imaging was performed using a self-made apparatus equipped with a tungsten filament X-ray tube and an excitation source of 50 kV and 200 μA. A digital camera was used for both photographing and video capture. The photograph exposure time was 1 second, and the video frame rate was 25 frames per second.

[0039] Based on the detection method described above, the following conclusions can be drawn: Radiative luminescence characteristics: AuCTCs all exhibit strong luminescence under X-ray excitation. This application evaluates their LY( ) by comparing them with the commercial scintillator LuAG(Ce). Figure 7 The results showed that COOEtPz-Au, CF3Pz-Au, MePz-Au, BrPz-Au, and ClPz-Au exhibited light yields of approximately 12627 photons / MeV, 12735 photons / MeV, 28528 photons / MeV, 21381 photons / MeV, and 25575 photons / MeV, respectively (as shown in Table 1). Figure 7As shown, by comparing the emission peak area of ​​AuCTC with that of LuAG(Ce), the light yields of COOEtPz-Au, CF3Pz-Au, MePz-Au, BrPz-Au, and ClPz-Au can be calculated to be 12627 photons / MeV, 12735 photons / MeV, 28528 photons / MeV, 21381 photons / MeV, and 25575 photons / MeV, respectively. This means that AuCTCs exhibit excellent photoluminescence properties, with light yields significantly superior to traditional scintillators, and also demonstrate excellent irradiation stability. Figure 6 As shown, AuCTC exhibits excellent stability under continuous X-ray irradiation (total dose of 1.269 Gy).

[0040] Dynamic X-ray imaging: AuCTC's AIE properties make it suitable for use as a solid-state scintillator. This application successfully fabricated a 6×4 cm² scintillator containing MePz-Au (50% by mass) using polyvinylidene fluoride-hexafluoropropylene as the polymer matrix. Under ultraviolet irradiation, the scintillator emits bright red fluorescence. Using a self-made X-ray imaging system, this application successfully demonstrated that the MePz-Au scintillator can efficiently and clearly reveal the internal structure of various objects under X-ray irradiation. For example, it effectively visualized internal structures such as hidden metal springs within pills and capsules, highlighting its potential applications in security inspections and medical imaging. Figure 8 ).

[0041] Therefore, to verify the dynamic imaging performance of the MePz-Au scintillator screen, this application conducted an angiography simulation experiment. The experimental results show that the MePz-Au scintillator screen can record real-time video at a fast frame rate of 25 frames per second, clearly capturing the flow of contrast agent simulating blood flow. Figure 9 This performance is attributed to the excellent LY value and relatively short emission lifetime of MePz-Au, enabling bright and clear imaging even with short frame intervals of 40 ms. This rapid scintillation response surpasses conventional angiography imaging in clinical applications. AuCTCs, as promising indirect scintillator materials, possess excellent light yield, low detection limit, and fast scintillation response. Furthermore, they offer simple synthesis methods and extremely low cost. These advantages make AuCTCs a superior alternative to traditional commercial scintillators.

[0042] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An application of a pyrazole-based trinuclear complex in X-ray imaging, characterized in that, The pyrazole-based trinuclear complex was used to prepare a scintillation screen material for X-ray imaging. The general structural formula of the pyrazole cyclotrinuclear complex is shown below: ； In the formula, R1, R2 and R3 are all substituents; the substituents include at least one of methyl, ethyl, trifluoromethyl, ethyl carboxylate, chlorine atom, bromine atom or iodine atom.

2. The application of the pyrazole-based trinuclear complex according to claim 1 in the field of X-ray imaging, characterized in that, The pyrazole-based trinuclear complex is used as a scintillator to prepare scintillator materials for simulated X-ray dynamic vascular imaging or security detection imaging.

3. The application of the pyrazole fin ring trinuclear complex according to claim 2 in the field of X-ray imaging, characterized in that, The flicker screen material is prepared through the following steps: Polyvinylidene fluoride-hexafluoropropylene and pyrazole tricyclic complex were mixed and added to N,N-dimethylformamide. The mixture was stirred evenly at a preset temperature and then electrospun to obtain a pyrazole tricyclic complex scintillator screen.

4. The application of the pyrazole fin ring trinuclear complex according to claim 3 in the field of X-ray imaging, characterized in that, The mass ratio of the polyvinylidene fluoride-hexafluoropropylene to the pyrazole tricyclic complex is 1-10:

1.

5. The application of the pyrazole fin ring trinuclear complex according to claim 3 in the field of X-ray imaging, characterized in that, The volume ratio of the N,N-dimethylformamide to the polyvinylidene fluoride-hexafluoropropylene is 1-5:

1.

6. The imaging application of the pyrazole-based finite ring trinuclear scintillator according to claim 3, characterized in that, The preset temperature is 35℃, and the stirring time is 15min-30min.

7. The imaging application of the pyrazole-based finite ring trinuclear scintillator according to claim 1, characterized in that, The pyrazole cyclotrinuclear complex as a scintillator has a light yield of 28,528 photons / MeV and a photoluminescence quantum yield of 73.2%.

8. A method for synthesizing a pyrazole-based trinuclear complex, characterized in that, Includes the following steps: Dissolve 1 mmol of ligand and 1 mmol of tetrachloroauric acid in a 30 mL:30 mL mixture of ethanol and acetone. Add triethylamine dropwise until a white precipitate forms. Continue stirring for 30 minutes, then filter to obtain a white precipitate. Wash the white precipitate with 10 mL of ethanol and air dry to obtain the final product.

9. The method for synthesizing the pyrazole-based trinuclear complex according to claim 8, characterized in that, The ligands include one or more of the following: 3,5-dimethyl-1H-pyrazole, 3,5-bis(trifluoromethyl)-1H-pyrazole, 3,5-carboxylic acid diethyl ester-1H-pyrazole, 4-chloro-1H-pyrazole and 4-bromo-1H-pyrazole.

10. A pyrazole-based trinuclear complex, characterized in that, Prepared by the method described in any one of claims 8-9.

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