Mono- and hexa-palladium doped silver nanoclusters stabilized by dithiolates

Abstract

The synthesis, via a co-reduction method, of the first Pd-containing silver-rich 21-metal-atom nanocluster passivated by dithiolates, [PdAg₂₀{S₂P(OⁿPr)₂}₁₂] (1), is reported. 1 is an 8 electron superatom isoelectronic to [Ag₂₁{S₂P(OⁱPr)₂}₁₂]⁺. The doping of Pd in 1 leads to its high stability against degradation in solution and shows red emission in MeTHF at 77 K. In addition, we report the X-ray crystal structure of a multi-palladium doped silver nanocluster, [Pd₆Ag₁₄(S){S₂P(OⁿPr)₂}₁₂] (2), for the first time. Its X-ray structure exhibits a sulfide-centered Pd₆Ag₂ rhombohedron surrounded by twelve additional silver atoms with S₆ symmetry. The XPS study and DFT calculations indicate that 2 contains Pd(0) and Ag(I) metals. A significant decrease in the electrochemical gap was observed in the SWVs of 2.