Synthesis of RhH-doped Au-Ag alloy nanoclusters and dopant evolution.

Doping atomically precise metal nanoclusters (NCs) with heterometals is a powerful method for tuning the physicochemical properties of the original NCs at the atomic level. While the heterometals incorporated into metal NCs are limited to group 10-12 metals with closed d-shells, the doping of open d-shell metals remains largely unexplored. Herein, we report the synthesis of Rh-doped Au-Ag alloy NCs by a metal-exchange reaction of [RhHAg 24 (SPhMe 2 ) 18 ] 2- NCs with an Au-thiolate complex. Combined experimental and theoretical structural studies revealed that the synthesized product is a dianionic [RhHAu x Ag 24- x (SPhMe 2 ) 18 ] 2- NC ( x = 8-12), consisting of RhH dopant, Au-rich kernel, and Ag-thiolate staple motifs, with the superatomic 8-electron configuration (1S 2 1P 6 ). Under aerobic conditions, the synthesized NCs underwent kernel evolution to generate a 6-electron [RhAu x Ag 24- x (SPhMe 2 ) 18 ] 1- NC (1S 2 1P 4 ), which was initiated by the desorption of hydride from the kernel. Structural analysis of the [RhHAu x Ag 24- x (SPhMe 2 ) 18 ] 2- NC suggests that the kernel evolution is induced by the change in chemical bonds surrounding the hydride in the Au-rich kernel.