X-Ray crystal structure, and optical and electrochemical properties of the Au15Ag3(SC6H11)14 nanocluster with a core–shell structure

Abstract

We report the X-ray crystallographic structure of an 18-metal atom Au–Ag bimetallic nanocluster (NC) formulated as [Au₁₅Ag₃(SC₆H₁₁)₁₄]. This NC consists of a Au₆Ag₃ bi-octahedral kernel, which is built up by two octahedral Au₃Ag₃ units through sharing one Ag₃ triangular face. The [Au₁₅Ag₃(SC₆H₁₁)₁₄] can be viewed as a core–shell structure with the doped Ag atoms as the core and Au atoms as the shell. Detailed analyses by UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements clearly show distinct differences in the electronic structure between [Au₁₅Ag₃(SC₆H₁₁)₁₄] and the homometal [Au₁₈(SC₆H₁₁)₁₄] NC. This study contributes to the deep understanding on bimetallic nanoclusters.