A gold nanocluster and its preparation method

Abstract

This invention application belongs to the field of cluster compound technology, and specifically discloses a gold nanocluster with the molecular formula [Au]. 22 L 14 [L is 2,4,6-triisopropylphenylacetylene.] This invention also relates to a method for preparing gold nanoclusters, comprising the following steps: adding 2,4,6-triisopropylphenylacetylene to a dichloromethane solution of Au(tht)Cl to prepare (AuL). n Polymers, and (AuL) n Polymer, [Au(tht)2]ClO4, and NaBH3CN were dissolved in a mixed solution of CH2Cl2 and EtOH. After stirring in the dark, the solution was extracted, filtered, and concentrated to obtain gold nanoclusters [Au]. 22 L 14 ].

Description

Technical Field

[0001] This invention belongs to the field of cluster technology, and specifically discloses a gold nanocluster and its preparation method. Background Technology

[0002] Atomic-precise gold nanoclusters are attracting increasing attention due to their importance in fundamental research and their potential applications in luminescence, catalysis, sensing, molecular electronics, and interdisciplinary materials. Gold clusters are susceptible to interference from other molecules or solvents in the environment; therefore, ligands play a crucial role in stabilizing the formed atomic clusters and controlling their composition and structure during their synthesis. Currently, thiol ligands and phosphine ligands are commonly used as protecting ligands, but their coordination modes are limited and lack diversity. Summary of the Invention

[0003] The purpose of this invention is to provide a gold nanocluster and its preparation method to solve the problem of unstable coordination of gold nanoclusters.

[0004] To achieve the above objectives, the technical solution of the present invention is: a gold nanocluster with the molecular formula [Au] 22 L 14 Au within gold nanoclusters 22 The nucleus can be divided into one Au 18 The polyhedral center is connected to four L–Au–L groups, where L represents 2,4,6-triisopropylphenylacetylene.

[0005] The working principle of this technical solution is as follows:

[0006] 2,4,6-Triisopropylphenylacetylene was selected as the ligand to prepare isocoordinated acetylene-based gold nanoclusters. 2,4,6-Triisopropylphenylacetylene is a substituted phenylacetylene ligand with sterically hindered groups at the 2, 4, and 6 positions, which can effectively prevent interference from other molecules or solvents in the environment, thus stabilizing the gold nanoclusters. The acetylene ligand, possessing an acetylene bond, can act as δ and π donors. This dual-functional coordination mode provides more diverse structural units, thereby enriching the structure and properties of gold nanoclusters.

[0007] The beneficial effects of this technical solution are as follows:

[0008] (1) The two isopropyl groups adjacent to the alkynyl group can prevent intermolecular aggregation and provide isolation between the central metal cluster and solvent molecules or ions, thereby stabilizing the atomic cluster;

[0009] (2) The para-isopropyl group can also regulate the polarity and solubility of the cluster, thereby enhancing the crystallinity of gold nanoclusters.

[0010] Furthermore, a method for preparing gold nanoclusters includes the following steps:

[0011] (1) Add 2,4,6-triisopropylphenylacetylene to a dichloromethane solution of Au(tht)Cl, stir for 30-60 minutes in the dark at room temperature, and filter the reaction solution to obtain (AuL). n polymer;

[0012] (2) The (AuL) prepared in step (1) n The polymer, [Au(tht)2]ClO4 and NaBH3CN were dissolved in a mixed solution of CH2Cl2 and EtOH. After stirring in the dark at room temperature for 12-18 hours, a dark red solution was obtained.

[0013] (3) Extraction with an extractant, followed by filtration and concentration. An auxiliary solvent is diffused into the concentrated solution, and the mixture is allowed to stand for 7-9 days to obtain dark red gold nanoclusters [Au]. 22 L 14 Crystal.

[0014] Furthermore, in step (1), the ratio of Au(tht)Cl to dichloromethane in the Au(tht)Cl dichloromethane solution is 0.05-0.1 mmol: 20-40 mL.

[0015] Furthermore, in step (2) (AuL) n The ratio of polymer, [Au(tht)2]ClO4, and NaBH3CN is 1.8-2.2:0.8-1.2:0.8-1.2. The volume ratio of CH2Cl2 to EtOH in the mixed solution of CH2Cl2 and EtOH is 0.8-1.2:0.8-1.2 (AuL). n The ratio of the polymer to the mixed solution of CH2Cl2 and EtOH is 0.1-0.2 mmol: 20-40 mL.

[0016] Furthermore, in step (3), the extractant is CH2Cl2 and the auxiliary solvent is n-hexane. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the gold nanoclusters according to an embodiment of the present invention;

[0018] Figure 2 Au is the gold nanocluster of the embodiment of the present invention. 22 Nuclear structure diagram;

[0019] Figure 3 Au nanoclusters of gold according to embodiments of the present invention 18 Diagram of the central unit structure of a polyhedron;

[0020] Figure 4Two sets of gold-acetylene bond structures in the gold nanoclusters of this invention;

[0021] Figure 5 A flowchart illustrating the preparation method of gold nanoclusters according to an embodiment of the present invention;

[0022] Figure 6 This is the mass spectrum of the gold nanoclusters in Example 1 of the present invention;

[0023] Figure 7 This is the ultraviolet absorption spectrum of the gold nanoclusters in Example 1 of the present invention. Detailed Implementation

[0024] The following detailed description illustrates the specific implementation methods:

[0025] The basic implementation examples are as follows: Figure 1 As shown, a gold nanocluster consists of 22 gold atoms and 14 alkynyl ligands. (The last sentence appears to be incomplete and possibly refers to a different topic.) Figure 2 and Figure 3 As shown, due to the central Au 22 The nucleus exhibits a polyhedral shape, while the entire cluster of molecules tends to be ellipsoidal, with Au inside. 22 The nucleus can be divided into an Au 18 The polyhedral center is connected to four RC≡C–Au–C≡CR groups; Au 18 The central unit of the polyhedron consists of two hexagonal double pyramids sharing a common edge and two triangular double pyramids on the sides; A 18 Four V-shaped RC≡C-Au-C≡CR groups are attached to the top and bottom of the center.

[0026] Au 22 Au-Au distance in the cluster to There is significant intermetallic contact between them. Figure 4 As shown, the gold nanoclusters contain two sets of alkynyl groups, including a nonlinear RC≡C–Au–C≡CR group A and a δ-bridged coordination group B (six alkynyl ligands). Group A comprises eight alkynyl ligands, where the C≡CR ligands employ a μ2-bridging mode, bonding with one gold center via a δ bond and with another gold center via a π bond. The other six alkynyl ligands belong to group B, representing a simple μ2-bridging coordination mode. The Au-C bond length of the δ bond is... to Within the range, the bond length of the π bond is to between.

[0027] The specific process of the embodiment is as follows: Figure 5 As shown:

[0028] 2,4,6-Triisopropylphenylacetylene was added to a solution of Au(tht)Cl in dichloromethane and stirred for 60 minutes at room temperature in the dark. The reaction solution was then filtered to obtain (AuL). n Polymer; Au(tht)Cl and Ag(tht)ClO4 were mixed in a dichloromethane solution and stirred in the dark at room temperature for 60 minutes. After filtration, [Au(tht)2]ClO4 was obtained; 42.4 mg of (AuL) was taken. n The polymer, 23.6 mg of [Au(tht)₂]ClO₄, and 3.14 mg of NaBH₃CN were added to 20 mL of a 1:1 (v / v) mixture of CH₂Cl₂ and EtOH. The mixture was stirred in the dark at room temperature for 12 hours. The resulting dark red solution was dried and concentrated using a rotary evaporator, then extracted with CH₂Cl₂. The CH₂Cl₂ solution was filtered and concentrated to approximately 5 mL. Hexane was diffused into the concentrated CH₂Cl₂ solution, and after standing for one week, dark red gold nanoclusters [Au(tht)₂]ClO₄ were obtained. 22 L 14 Crystals. Example: Gold nanoclusters [Au] 22 L 14 Crystal mass spectrum as shown Figure 6 As shown in the enlarged spectral section, the species [M+H] is displayed. + Measured and simulated values. Example: Gold nanoclusters [Au] 22 L 14 The ultraviolet absorption spectrum of the crystal is shown below. Figure 7 As shown in the figure. The yield of the example is as high as about 34%. This method has the advantages of being easy to operate, highly applicable, and easy to industrialize.

[0029] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics in the solutions is not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A gold nanocluster, characterized in that, The molecular formula is [Au] 22 L 14 Au within gold nanoclusters 22 The nucleus is divided into one Au 18 The polyhedral center is connected to four L–Au–L groups, where L represents 2,4,6-triisopropylphenylacetylene.

2. A method for preparing gold nanoclusters according to claim 1, characterized in that, Includes the following steps: (1) Add 2,4,6-triisopropylphenylacetylene to a dichloromethane solution of Au(tht)Cl, stir for 30-60 minutes in the dark at room temperature, and filter the reaction solution to obtain (AuL). n polymer; (2) The (AuL) prepared in step (1) n The polymer, [Au(tht)2]ClO4 and NaBH3CN were dissolved in a mixed solution of CH2Cl2 and EtOH. After stirring in the dark at room temperature for 12-18 hours, a dark red solution was obtained. (3) Extraction with an extractant, filtration and concentration, diffusion of an auxiliary solvent into the concentrated solution, and standing for 7-9 days to obtain dark red gold nanoclusters [Au]. 22 L 14 Crystal.

3. The method for preparing gold nanoclusters according to claim 2, characterized in that, In step (1), the ratio of Au(tht)Cl to dichloromethane in the Au(tht)Cl dichloromethane solution is 0.05-0.1 mmol: 20-40 mL.

4. The method for preparing gold nanoclusters according to claim 2, characterized in that, In step (2) (AuL) n The ratio of polymer, [Au(tht)2]ClO4, and NaBH3CN is 1.8-2.2 : 0.8-1.2 : 0.8-1.

2. The volume ratio of CH2Cl2 to EtOH in the mixed solution of CH2Cl2 and EtOH is 0.8-1.2 : 0.8-1.2 (AuL). n The ratio of the polymer to the mixed solution of CH2Cl2 and EtOH is 0.1-0.2 mmol: 20-40 mL.

5. The method for preparing gold nanoclusters according to claim 2, characterized in that, In step (3), the extractant is CH2Cl2 and the auxiliary solvent is n-hexane.

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