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

The synthesis, via a co-reduction method, of the first Pd-containing silver-rich 21-metal-atom nanocluster passivated by dithiolates, [PdAg20{S2P((OPr)-Pr-n)(2)}(12)] (1), is reported. 1 is an 8 electron superatom isoelectronic to [Ag-21{S2P((OPr)-Pr-i)(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((OPr)-Pr-n)(2)}(12)] (2), for the first time. Its X-ray structure exhibits a sulfide-centered Pd6Ag2 rhombohedron surrounded by twelve additional silver atoms with S-6 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.