Au2Si20: a honeycomb-shaped structure with short Au−Au single bond at the centre coordinated by twelve Si5 pentagons and reinforced by strong Au−Si interactions and aromaticity

Abstract

Investigating the structures and properties of large-sized silicon clusters doped with multiple Au atoms can provide valuable microscopic information for gold-catalyzed high-quality Si nanowire and Au−Si alloying reactions, and also for the production of cluster-assembled functional materials. In this work, a quantum chemical investigation on the structural and electronic properties of double Au atoms doped Si20 cluster using density functional theory calculations was performed. The lowest-lying isomers of (The meaning of the acronym: refers to Au2Si20 cluster with a negative charge, neutral state, and a positive charge, respectively.) were found to all adopt a C 2h symmetric Au2-endohedral honeycomb-shaped structure consisting of twelve Si5 pentagons. Interestingly, in the anionic, neutral, and cationic Au2Si20, twelve Si5 pentagons can be stabilised by two Au atoms. The two Au atoms in tend to occupy high coordinate sites and exhibit strong aurophilic interactions. In addition, the Au−Si bonds show both covalent and ionic bonding characters. Moreover, , Au2Si20, and are all aromatic.