Acta Phys. -Chim. Sin. ›› 2018, Vol. 34 ›› Issue (7): 825-829.doi: 10.3866/PKU.WHXB201712013

Special Issue: 原子水平上精确控制纳米簇和纳米粒子

• ARTICLE • Previous Articles     Next Articles

Synthesis of High Yield Au21(SR)15 Nanoclusters

Xiuqing REN1,2,Xinzhang LIN1,3,Xuemei FU1,3,Chao LIU1,*(),Jinghui YAN2,Jiahui HUANG1,*()   

  1. 1 Gold Catalysis Research Center, State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, P. R. China
    2 School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China
    3 University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2017-10-27 Published:2018-03-26
  • Contact: Chao LIU,Jiahui HUANG E-mail:chaoliu@dicp.ac.cn;jiahuihuang@dicp.ac.cn
  • Supported by:
    the National Natural Science Foundation of China(21601178);the National Natural Science Foundation of China(21473186);the Young Thousand Talents Program of China, and the "Strategic Priority Research Program" of the Chinese Academy of Sciences(XDA09030103)

Abstract:

In recent years, Au nanoclusters have attracted much attention as new nanomaterials, which contain several to two hundred Au atoms and are protected by ligands. The structures and properties of Au nanoclusters are usually sensitive to the particle size due to quantum confinement effect. Au nanoclusters have been applied to different fields, such as optical properties, catalysis, and biology. There are two common methods for the synthesis of atomically precise Au nanoclusters: "size focusing" and "ligand exchange". Although a series of Au nanocluster have been obtained via "size focusing" and "ligand exchange", obtaining high yield of such Au nanoclusters is a challenge. Au21(S-Adam)15 was previously synthesized via etching Au18 nanoclusters with excess thiols, and its crystal structure was determined by X-ray diffraction crystallography; however, the yield of Au nanoclusters was low. In this study, we prepared Au21(S-Adam)15 in high yield via conversion of Au23(S-Adam)16 to Au21(S-Adam)15. Firstly, Au23(S-Adam)16 nanoclusters were synthesized using adamantanethiols(HS-Adam) as the protecting ligand and HAuCl4 as the gold resource in ethyl acetate solvent. Au23(S-Adam)16 were further etched with excess thiols at room temperature. After reacting for 30 min, highly pure Au21(S-Adam)15, with high yield of ~20% based on HAuCl4 precursor, were successfully prepared. Au23(S-Adam)16 and Au21(S-Adam)15 were characterized by electrospray ionization (ESI), UV-Vis absorption spectroscopy, matrix-assisted laser desorption ionization (MALDI) mass spectrometry, and thermogravimetric analysis (TGA). ESI-MS and UV-Vis spectra confirm the high purity of the Au23(S-Adam)16. After conversion, UV-Vis spectra show the absorption peaks of Au21(S-Adam)15 at 700, 540, 435 and 380 nm. The MALDI-MS of Au21(S-Adam)15 shows several peaks at 6502, 6471, 6106, 5411, and 5048, assigned to Au21(S-Adam)14S, Au21(S-Adam)14, Au20(S-Adam)13, Au19(S-Adam)10, and Au18(S-Adam)9, respectively. The fragments of Au nanoclusters were produced by the strong laser intensity, which easily removes carbon tails from HS-Adam. Thermogravimetric analysis (TGA) was also performed to check the purity of Au21(S-Adam)15 nanoclusters. The TGA curve shows a weight loss of 42% (expected value, 38%). UV-Vis absorption spectroscopy was performed to track the conversion of Au23(S-Adam)16 to Au21(S-Adam)15. It was found that Au23(S-Adam)16 can convert to Au21(S-Adam)15 with a conversion efficiency of up to 97%, using excess thiols at room temperature within 30 min. In general, we successfully synthesized highly pure Au21(S-Adam)15 nanoclusters, with high yield of ∼20% based on HAuCl4, by etching Au23(S-Adam)16 with excess thiols at room temperature.

Key words: Gold nanocluster, Au21(S-Adam)15, High-yield

MSC2000: 

  • O641