Doping effect on the structure and properties of eight-electron silver nanoclusters

The bimetallic M20 and M21 compounds, {[Cu3Ag17{S2P(OiPr)2}12]0.5 [Cu4Ag16{S2P(OiPr)2}12]0.5} ({[1a]0.5[1b]0.5}) [Cu4Ag17{S2P(OiPr)2}12](PF6) (2), have been structurally characterized, in which the Cu(I) ions are randomly distributed on eight outer positions capping eight-electron [Ag13]5+ core. DFT calculations show that statistical disorder results from nearly neutral preference of copper to occupy any positions. Surprisingly, UV–Vis absorption spectra nanoclusters display an almost identical profile as their homometallic [Ag20{S2P(OiPr)2}12] [Ag21{S2P(OiPr)2}12]+ relatives. This is rationalized by TD-DFT calculations, frontier orbitals such alloys largely independent nature metal ions. A blue-shifted observed upon replacing Au central Ag atom 2, forming trimetallic compound [Cu4AuAg16{S2P(OiPr)2}12](PF6) (3).