Total Structure Determination of Au_(21)(S-Adm)_(15) and Geometrical/ Electronic Structure Evolution of Thiolated Gold Nanoclusters

摘要

The larger size gold nanoparticles typically adopt a face-centered cubic (fcc) atomic packing, while in the ultrasmall nanoclusters the packing styles of Au atoms are diverse, including fcc, hexagonal close packing (hcp), and body-centered cubic (bcc), depending on the ligand protection. The possible conversion between these packing structures is largely unknown. Herein, we report the growth of a new Au_(21)(S-Adm)_(15) nanocluster (S-Adm = adamantanethiolate) from Au_(18)(SR)_(14) (SR = cyclohexylth-iol), with the total structure determined by X-ray crystallography. It is discovered that the hcp Au_9-core in Au_(18)(SR)_(14) is transformed to a fcc Au_(10)-core in Au_(21)(S-Adm)_(15). Combining with density functional theory (DFT) calculations, we provide critical information about the growth mechanism (geometrical and electronic structure) and the origin of fee-structure formation for the thiolate-protected gold nanoclusters.