Density Functional Theory Studies on Structure, Ligand Exchange, and Optical Properties of Ligand-Protected Gold Nanoclusters: Thiolate versus Selenolate

Abstract

Atomically precise thiolate-protected Au nanoclusters (NCs), i.e. Aum(SR)n, have attracted intensive research interest during the past few years. Recently, the synthesis and isolation of selenolate-protected gold clusters (Aum(SeR)n) via the ligand exchange of thiolate with selenol were achieved, which demonstrated identical compositions to those of thiolate-protected Au NCs. In this study, we perform a comprehensive theoretical study on the structure, electronic structure, and electronic optical absorption properties of 11 selenolate-protected gold clusters on the basis of density functional theory (DFT) calculations. Our results propose that the selenolate-protected Au NCs with framework structure identical to the thiolated ones are stable local minima. The ligand effect is proposed to understand the distinct geometrical structures of Au24(SeR)20 and Au24(SR)20 NCs. In addition, the optical absorption properties of thiolate- and selenolate-protected Au NCs are compared via the time-dependent density fun...