Eight‐Electron Silver and Mixed Gold/Silver Nanoclusters Stabilized by Selenium Donor Ligands

The first atomically and structurally precise silver‐nanoclusters stabilized by Se‐donor ligands, [Ag 20 {Se 2 P(O i Pr) 2 } 12 ] ( 3 ) and [Ag 21 {Se 2 P(OEt) 2 } 12 ] + ( 4 ), were isolated by ligand replacement reaction of [Ag 20 {S 2 P(O i Pr) 2 } 12 ] ( 1 ) and [Ag 21 {S 2 P(O i Pr) 2 } 12 ] + ( 2 ), respectively. Furthermore, doping reactions of 4 with Au(PPh 3 )Cl resulted in the formation of [AuAg 20 {Se 2 P(OEt) 2 } 12 ] + ( 5 ). Structures of 3 , 4 , and 5 were determined by single‐crystal X‐ray diffraction. The anatomy of cluster 3 with an Ag 20 core having C 3 symmetry is very similar to that of its dithiophosphate analogue 1 . Clusters 4 and 5 exhibit an Ag 21 and Au@Ag 20 core of O h symmetry composed of eight silver capping atoms in a cubic arrangement and encapsulating an Ag 13 and Au@Ag 12 centered icosahedron, respectively. Both ligand exchange and heteroatom doping result in significant changes in optical and emissive properties for chalcogen‐passivated silver nanoparticles, which have been theoretically confirmed as 8‐electron superatoms.