The one/two atom size-reduction of [Au23SCy16]− induced by the [Au6(dppp)4]2+ cluster

Abstract

The recent progress in atomically precise metal (Au, Ag etc.) nanoclusters has greatly enriched the molecular-level mechanistic understanding of metal nanomaterials. Herein, using two meta-stable (easy formation, easy transformation) clusters, i.e. [Au₂₃SCy₁₆]⁻ and [Au₆(dppp)₄]²⁺ (HSCy and dppp denote cyclohexanethiol and 1,3-bis(diphenylphosphino)propane), as the reaction precursors, the etching of Au₂₃ occurs smoothly, giving the one/two-atom size-reduced [Au₂₁SCy₁₂(dppp)₂]⁺ and [Au₂₂SCy₁₄(dppp)]²⁺ as the major products. Structural analysis and DFT calculations indicate that the active reaction site of Au₂₃ lies in the core–shell interference of the bi-capped icosahedral Au₁₅ core and the AuS₂ motifs. The fluorescence, band gap, and thermostability of the Au₂₁ cluster products are improved compared to that of the Au₂₃ precursors.