Homoleptic Platinum/Silver Superatoms Protected by Dithiolates: Linear Assemblies of Two and Three Centered Icosahedra Isolobal to Ne and I.

Three bimetallic platinum/silver nanoclusters, PtAg(dtp) (), PtAg(dtp) (), and PtAg(dtp) () (dtp: dipropyl dithiophosphate), with cluster electron counts of 8, 16, and 22, respectively, were produced via a one-phase coreduction method. Single-crystal X-ray structures reveal that their inner cores can be visualized as consisting of one, two, and three centered icosahedral Pt@Ag units, respectively. In and , these units are vertex-sharing and are assembled linearly. Intriguingly, the 22-electron alloy () is isolobal to the linear triiodide anion, I, and represents the first example of a cluster made of three superatoms whose bonding characteristics are similar to those of a triatomic molecular species.