A water-soluble gold nanocluster material with a single crystal structure

Abstract

The present invention discloses a water-soluble nano-gold cluster material with a single crystal structure protected by a thiol ligand, which belongs to the intersection of nano-materials and coordination chemistry. The chemical formula of the nano-gold cluster is: Au 25 S 18 P 18 C 378 H 378 Br 17 (Abbreviated as: Au 25 L 18 ), belongs to the trigonal system, and the space group is R ‑3. The gold nanoclusters are relatively small (~2 nm) and have good dispersibility in aqueous solutions. The gold nanoclusters also disperse well in various physiological solutions for a long period of time.

Description

Technical Field

[0001] The present invention belongs to the intersecting field of nanomaterials and coordination chemistry, and particularly relates to an atomic-level precise water-soluble nanogold cluster material. Background Art

[0002] Over the past few decades, gold nanoclusters (Au NCs) with excellent monodispersity and well-defined structures have attracted great research interest. This is not only because they possess novel properties such as tunable luminescence and diverse activities, but also because the atomically precise clusters facilitate the unraveling of the relationship between their structure and properties.

[0003] However, the poor water solubility caused by organic ligands is a disadvantage. To address this obstacle, some ligands with carboxyl or sulfonic acid groups are used to stabilize clusters in solution by increasing the surface charge, while the direct synthesis of water-soluble AuNCs always produces a mixture of multiple clusters, which needs to be subsequently purified by electrophoresis or step-by-step precipitation. Another commonly used method to obtain water-soluble Au NCs is to use atomically precise NCs as precursors for ligand exchange. Most of these products are characterized by extended X-ray absorption fine structure (EXAFS) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). However, this method usually leads to structural changes, such as etching or growth of the core. So far, there are still few reports of water-soluble Au NCs with a single crystal structure. Summary of the Invention

[0004] The present invention aims to provide a water-soluble atomic-level precise nano-gold cluster material protected by a thiol ligand, and another aim is to provide a preparation method thereof.

[0005] To achieve the purpose of the present invention, the chemical formula of the nano-gold cluster material is Au 25 S 18 P 18 C 378 H 378 Br 17 , abbreviated as: Au 25 L 18 , belongs to the trigonal crystal system; the space group is R-3, α=90°, β=90°, γ=120°, L represents 3-(triphenylphosphine)propane-1-sodium thiobromide ligand,

[0006] Its structural formula is as follows:

[0007]

[0008] The nano-gold cluster material of the present invention is prepared by the following steps:

[0009] Dissolve tetrahydrothiophene gold chloride in dichloromethane (DCM) and stir at room temperature until the solution is clear. Add a methanol solution containing sodium 3-(triphenylphosphine)propane-1-thiobromide ligand and stir at room temperature to react. Then, add a methanol solution containing sodium borohydride and stir at room temperature to react. After the reaction is complete, rotary evaporate the solvent to form a dark brown solid. Dissolve the solid in DCM solution, centrifuge, filter, and diffuse the supernatant with toluene to obtain crystals. Collect the crystals and air-dry at room temperature.

[0010] The nano-gold cluster material is composed of a central icosahedral Au 13 The core consists of six one-dimensional Au2S3 motifs, and the entire cluster is protected by 18 organic ligands ( Figure 2 shown).

[0011] The nano-gold cluster material has an ultra-small size (~2nm) ( Figure 3 As shown), it has good dispersibility in aqueous solution ( Figure 4 As shown). The prepared Au 25 The clusters also disperse well in various physiological solutions for a long time ( Figure 5 shown).

[0012] The beneficial effects of the present invention are as follows: due to the lipophilicity and hydrophilicity of triphenylphosphine cation, the nano-gold cluster material can be dissolved in water, has good dispersibility, and has high stability in aqueous solution, and has good biological application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a single crystal structure diagram of the nano-gold cluster material of the present invention.

[0014] Figure 2 This is a diagram of the core structure and ligand coordination pattern of the nano-gold cluster material of the present invention.

[0015] Figure 3 This is a transmission electron microscope image of the gold nanocluster material of the present invention.

[0016] Figure 4 This is a dynamic light scattering diagram of the gold nanocluster material of the present invention.

[0017] Figure 5 This is a diagram showing the stability of the gold nanocluster material of the present invention in different physiological solutions. DETAILED DESCRIPTION

[0018] The present invention will be further described below by way of examples:

[0019] Example 1: Synthesis of gold nanocluster materials of the present invention

[0020] Dissolve tetrahydrothiophene gold chloride in dichloromethane (DCM) and stir at room temperature until the solution is clear. Add a methanol solution containing sodium 3-(triphenylphosphine)propane-1-thiobromide ligand and stir at room temperature to react. Then add a methanol solution containing sodium borohydride and stir at room temperature overnight. After the reaction, rotary evaporate the solvent to form a dark brown solid. Dissolve the solid in DCM solution, centrifuge at 10,000 rpm for 3 minutes, filter, and diffuse the supernatant with toluene at 4°C for one week to obtain brown block crystals. Collect the crystals, air-dry at room temperature, and use them as material for property testing.

[0021] The gold nanocluster material of the present invention prepared in Example 1 was further characterized as follows:

[0022] (1) Crystal structure determination

[0023] The X-ray single crystal diffraction data of the complex were measured on a Rigaku XtaLAB Pro single crystal diffractometer using a single crystal sample of appropriate size. The data were obtained using Cu-Kα radiation. Diffraction patterns were collected at 200 K using the ω scan mode. The structure was initially determined using the SHELXS-97 program using a direct method, followed by full-matrix least-squares refinement using the SHELXL-97 program. Solvent molecules were treated using the mask program in OLEX2. All non-hydrogen atoms were refined using the anisotropic thermal parameter method. All hydrogen atoms were included at ideal positions. Detailed crystallographic data are shown in Table 1; key bond length data are shown in Table 2.

[0024] Table 1 Main crystallographic data of the nano-gold cluster material of the present invention

[0025] Table 1 Main crystallographic data

[0026]

[0027] Table 2Au 25 L 18 Important bond lengths

[0028]

[0029] Symmetric code: 1 -Y,+XY,+Z; 2 +Y,-X+Y,1-Z; 3 +YX,-X,+Z; 4 -X,-Y,1-Z; 5 -Y+X,+X,1-

[0030] The above embodiments are only used to illustrate the content of the present invention. In addition, the present invention has other embodiments. However, any technical solution formed by equivalent replacement or equivalent deformation falls within the scope of protection of the present invention.

Claims

1. A water-soluble gold nanocluster compound, characterized in that: Its chemical formula is: Au 25 S 18 P 18 C 378 H 378 Br 17 , abbreviated as: Au 25 L 18 , belongs to the trigonal crystal system; the space group is R-3, α=90°, β=90°, γ=120°, Wherein, L is 3-(triphenylphosphine) propane-1-sodium thiobromide ligand, and the simplified structural formula is as follows:

2. The water-soluble gold nanocluster material according to claim 1, wherein: It consists of a central icosahedron Au 13 The core consists of six one-dimensional Au2S3 motifs, and the entire cluster is protected by 18 organic ligands, which are sodium 3-(triphenylphosphine)propane-1-thiobromide.

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