Au2Si20: a honeycomb-shaped structure with short Au-Au single bond at the centre coordinated by twelve Si(5)pentagons and reinforced by strong Au-Si interactions and aromaticity

摘要

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 Si(20)cluster using density functional theory calculations was performed. The lowest-lying isomers ofAu2Si20-/0/+(The meaning of the acronym:Au2Si20-/0/+refers to Au(2)Si(20)cluster with a negative charge, neutral state, and a positive charge, respectively.) were found to all adopt aC(2h)symmetric Au-2-endohedral honeycomb-shaped structure consisting of twelve Si(5)pentagons. Interestingly, in the anionic, neutral, and cationic Au2Si20, twelve Si(5)pentagons can be stabilised by two Au atoms. The two Au atoms inAu2Si20-/0/+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-, Au2Si20, andAu2Si20+are all aromatic.