The one/two atom size-reduction of [Au 23 SCy 16 ] - induced by the [Au 6 (dppp) 4 ] 2+ cluster.

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. [Au 23 SCy 16 ] - and [Au 6 (dppp) 4 ] 2+ (HSCy and dppp denote cyclohexanethiol and 1,3-bis(diphenylphosphino)propane), as the reaction precursors, the etching of Au 23 occurs smoothly, giving the one/two-atom size-reduced [Au 21 SCy 12 (dppp) 2 ] + and [Au 22 SCy 14 (dppp)] 2+ as the major products. Structural analysis and DFT calculations indicate that the active reaction site of Au 23 lies in the core-shell interference of the bi-capped icosahedral Au 15 core and the AuS 2 motifs. The fluorescence, band gap, and thermostability of the Au 21 cluster products are improved compared to that of the Au 23 precursors.