A tert-butyl acetylene ligand protected silver cluster, a preparation method thereof and application thereof in x-ray detection

Abstract

The present application belongs to the cross field of coordination chemistry and nanomaterials, discloses a tert-butyl acetylene ligand protected silver cluster and a preparation method thereof and application thereof in X-ray detection. 72 H 109 Ag 14 ClO (abbreviation: Ag 14 ), belongs to the trigonal system, and the space group is R-3. Under X-ray irradiation, it changes from white or colorless to purple, and the fluorescence color also changes from blue to orange red. The sample after color change is dissolved in a methanol solution for recrystallization, and can be restored to the initial state. In a relatively wide temperature range (77K-330K), the Ag 14 sample can be induced to change color by X-ray, which opens up a new way for developing a new type of cluster-based X-ray detection material which is cheap, simple and recyclable.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of coordination chemistry and nanomaterials, and relates to an ultrastable silver nanocluster protected by tert-butylacetylene ligand prepared by a template method, its preparation method, and its application in X-ray detection. Background Technology

[0002] Atomic-precise coin metal (gold, silver, copper) clusters are a class of clusters with precise atomic structures, formed by three or more coin metal atoms through metalophilic interactions, with an outer layer protected by organic ligands. Nanoclusters represent a state of matter between atoms, molecules, and bulk materials, serving as a bridge connecting atoms, molecules, and macroscopic matter. Their size is typically on the nanometer scale, and they often exhibit quantum confinement effects, leading to many novel phenomena and properties. Their excellent photophysical properties and potential applications in catalysis, bioimaging, and other fields have become a research hotspot in materials science and inorganic chemistry in recent years.

[0003] Current research on coin metal nanoclusters mainly focuses on the synthesis and application of novel nanoclusters. However, the stability of reported coin metal nanoclusters at room temperature is relatively poor. These defects greatly hinder the application and development of nanoclusters. Therefore, designing and synthesizing atomically precise and structurally stable nanoclusters is one of the key research areas in the field of nanoclusters. Summary of the Invention

[0004] The present invention aims to provide an ultra-stable silver nanocluster protected by tert-butylacetylene; another objective is to provide a method for its preparation; and yet another objective is to provide the application of the silver nanocluster in X-ray detection.

[0005] To achieve the objectives of this invention, ultrastable tert-butylacetylene-protected silver nanoclusters were prepared using a template method, with the chemical formula: C 72 H 109 Ag 14 ClO (abbreviated as Ag) 14 It belongs to the trigonal crystal system, space group R-3, Ag 14 : α=90°, β=90°, γ=120°.

[0006] The method for preparing tert-butylacetylene silver of the present invention is achieved through the following steps:

[0007] Silver oxide was added to ammonia water and stirred at room temperature. Then, a mixture of tert-butylacetylene and ethanol was added and stirred at room temperature. After filtration, washing, and vacuum drying, the precursor was obtained. t BuC≡CAg) n .

[0008] The method for preparing silver nanoclusters of the present invention is achieved through the following steps:

[0009] The aforementioned precursor and silver trifluoroacetate were dispersed in a mixed solution of methanol and acetonitrile. Sodium chloride was added, and the mixture was sonicated until clear. The mixture was then placed in a Teflon-lined container and heated for reaction. The mixture was removed, filtered, and evaporated to obtain colorless rhomboid blocky crystals, which were the target substance.

[0010] This silver nanocluster consists of a metallic framework of fourteen silver atoms, with a -1 valent chloride ion at the center of the framework and twelve tert-butylacetylene atoms coordinated around it. Figure 1 (As shown). Ag 14 The cage shell is also described as a hexahedron composed of eight vertex silver atoms, with Ag-Ag separation ranging from 3.565 to [missing value]. Moreover, in Ag 14 Each face of the hexahedron of the cage housing has an additional silver ion ( ). Figure 2 (As shown). At the center of the cage, there is a chloride ion precisely on the six-fold symmetry axis. The distance between the chloride ion in the cage and the vertex Ag atom is... ( Figure 3 (As shown).

[0011] The ultrastable silver nanoclusters Ag of this invention 14 Its properties are described in detail below:

[0012] This material possesses an ultra-stable crystal structure, maintaining its crystalline structure even at a high temperature of 180℃. Figure 4 (As shown). Cluster materials with ultra-high stability are a prerequisite for their further application and a goal pursued by cluster researchers. 14 The color of the clusters, whether in powder or crystalline form, changes from white or colorless to purple within a very short time (30 seconds) under X-ray irradiation. Figure 5 As shown), and its fluorescent color also changes, from blue to orange-red (as shown). Figure 6 (As shown). This process is irreversible under normal conditions, but the sample can be restored to its initial state by dissolving the discolored sample in a methanol solution and recrystallizing it. Characterization combined with theoretical calculations suggests that Ag... 14 The color change is because the chloride ions, after receiving energy from the X-rays, generate secondary electrons that are captured by silver atoms, causing some silver atoms to change their valence from +1 to 0. Figure 7 As shown). This leads to a change in the electronic structure of the entire cluster molecule, which is believed to be the reason for the change in fluorescence (as shown). Figure 8 As shown). Ag... over a relatively wide temperature range (77K-330K) 14 The samples can all be induced to change color by X-rays, which is superior to many conventional X-ray color-changing materials.

[0013] The beneficial effects of this invention are as follows: Silver nanoclusters were constructed based on the interaction between organic protective ligands and counter ion templates and metals. This invention endows them with specific properties—X-ray induced color change and fluorescence color change—by introducing counter ions. The silver nanoclusters of this invention exhibit high stability, maintaining a crystalline structure at 180°C, and can be X-ray induced to change color over a wide temperature range. Furthermore, the sample can be restored to its initial state through recrystallization, demonstrating excellent potential for X-ray detection. Attached Figure Description

[0014] Figure 1 Ag of the present invention 14 A schematic diagram of the structure of nanoclusters.

[0015] Figure 2 Ag of the present invention 14 Schematic diagram of the assembly of a nanocluster metal core.

[0016] Figure 3 Ag of the present invention 14 A schematic diagram showing the distance from chloride ions to the apex silver atom in a nanocluster.

[0017] Figure 4 Ag of the present invention 14 Thermogravimetric analysis diagram of nanoclusters.

[0018] Figure 5 Ag of the present invention 14 Ultraviolet diffuse reflectance analysis diagram of nanoclusters in solid form.

[0019] Figure 6 Ag of the present invention 14 Excitation-emission curves of nanoclusters.

[0020] Figure 7 Ag of the present invention 14 Electron spin resonance analysis diagram of nanoclusters.

[0021] Figure 8 Ag of the present invention 14 Electron potential energy distribution before and after X-ray irradiation of nanoclusters. Detailed Implementation

[0022] The invention will be further illustrated by the following examples:

[0023] Example 1: Precursor body ( t BuC≡CAg) n Synthesis

[0024] Silver oxide (1 g, 4.3 mmol) was weighed into a 100 mL flask and dissolved in 50 mL of ammonia. Tert-butylacetylene (1164 μL, 9.46 mmol) was added to 5 mL of ethanol, and the mixture was stirred until a white precipitate formed immediately. After stirring overnight in the dark, the white precipitate was filtered out and washed with ethanol and ether to obtain 1.2 g ( t BuC≡CAg) n (Yield 74%)

[0025] Example 2: Synthesis of Silver Nanoclusters of the Present Invention

[0026] Silver trifluoroacetate (22.1 mg, 0.1 mmol) and ( t BuAgC≡C) n (78 mg, 0.4 mmol) was dissolved in 6 mL of methanol / acetonitrile solution (1:1). Sodium chloride (3 mg, 0.05 mmol) was added to the resulting solution and sonicated until the mixture became clear. The mixture was sealed in a Teflon-lined container and heated to 80 °C for reaction. After cooling to room temperature, the colorless solution was filtered, and the filtrate was allowed to evaporate slowly in air at room temperature, protected from light. Ag 14 The freshly prepared crystals were deposited as colorless crystals, filtered, and collected (Scheme 1). Yield: 44.2% (40.0 mg) (based on...) t BuAgC≡C) n ).

[0027] The silver nanoclusters of the present invention prepared in Example 2 were further characterized as follows:

[0028] (1) Crystal structure determination

[0029] X-ray single-crystal diffraction data of the complexes were determined using appropriately sized single-crystal samples on a Rigaku XtaLAB Pro single-crystal diffractometer. All data were obtained using graphite-monochromated Cu-Kα rays. The diffraction source was collected at 200 K using ω-scan mode, and corrected for Lp factor and semi-empirical absorption. Structural analysis was performed by first obtaining the initial structure using the direct method with the SHELXL-97 program, and then refining it using the full-matrix least squares method with the SHELXL-97 program. All non-hydrogen atoms were refined using anisotropic thermal parameter methods. All hydrogen atoms were refined using isotropic thermal parameter methods. Detailed crystallographic data are shown in Table 1; important bond length data are shown in Table 2.

[0030] Example 3: X-ray detection

[0031] When the obtained silver nanocluster crystal or powder sample is placed under X-rays, it can be seen that the sample changes from colorless or white to purple in a very short time (30 seconds). Irradiation with a 365nm ultraviolet lamp will show orange-red fluorescence. The discolored sample can be restored to its original state by dissolving it in methanol solution and recrystallizing it, and it can be used for X-ray detection again.

[0032] Table 1. Main crystallographic data of the heterometallic cluster material of the present invention.

[0033] Table 1. Main crystallographic data

[0034]

[0035] R1=∑||F o |-|F c || / ∑|F o |.wR2=[∑w(F o 2 -F c 2 ) 2 / ∑w(F o 2 ) 2 ] 1 / 2

[0036] Table 2 R-NHC ql -AuCu4-I important bond length

[0037]

[0038] The above embodiments are only used to illustrate the content of this invention. Other embodiments of this invention are also possible. However, all technical solutions formed by equivalent substitution or equivalent modification fall within the protection scope of this invention.

Claims

1. A silver nanocluster protected by a tert-butylacetylene ligand, characterized in that: Its chemical formula is: C 72 H 109 Ag 14 ClO, abbreviated as Ag 14 It belongs to the trigonal crystal system, space group R-3, Ag 14 : a = 16.3356(8) Å, b = 16.3356(8) Å, c = 29.4449(14) Å, V = 6804.7(7) Å 3 , α = 90°, β = 90° γ =120°.

2. The silver nanoclusters protected by tert-butylacetylene ligands as described in claim 1, characterized in that: The silver nanoclusters consist of a metallic framework composed of fourteen silver atoms, with a -1 valence chloride ion at the center of the framework and twelve tert-butylacetylene atoms coordinated around it; Ag 14 The cage shell is a hexahedron composed of eight vertex silver atoms, in Ag 14 Each face of the outer hexahedron has an additional silver ion on its outside.

3. A method for preparing silver nanoclusters protected by tert-butylacetylene ligands as described in claim 1, characterized in that: This can be achieved through the following steps: (1) Silver oxide was added to ammonia water and stirred at room temperature, then a mixture of tert-butylacetylene and ethanol was added and reacted at room temperature; after filtration, washing, and vacuum drying, the precursor was obtained. t BuC≡CAg) n ; (2) The above precursor and silver trifluoroacetate were dispersed in a mixed solution of methanol and acetonitrile, sodium chloride was added, and the mixture was sonicated until it became clear. The mixture was then placed in a Teflon liner and heated to react. After filtration and evaporation, the target substance was obtained.

4. The application of the silver nanoclusters protected by the tert-butylacetylene ligand as described in claim 1, characterized in that: When placed under X-rays, its color changes from colorless or white to purple, making it suitable for use as a non-diagnostic X-ray detection material.

5. The application of the silver nanoclusters protected by the tert-butylacetylene ligand as described in claim 4, characterized in that: The discolored silver nanoclusters were dissolved in methanol and recrystallized to restore their original state before discoloration, and then used as non-diagnostic X-ray detection materials.

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