Homoleptic Platinum/Silver Superatoms Protected by Dithiolates: Linear Assemblies of Two and Three Centered Icosahedra Isolobal to Ne₂ and I₃^–

Abstract

Three bimetallic platinum/silver nanoclusters, PtAg₂₀(dtp)₁₂ (<b>1</b>), Pt₂Ag₃₃(dtp)₁₇ (<b>2</b>), and Pt₃Ag₄₄(dtp)₂₂ (<b>3</b>) (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@Ag₁₂ units, respectively. In <b>2</b> and <b>3</b>, these units are vertex-sharing and are assembled linearly. Intriguingly, the 22-electron alloy (<b>3</b>) is isolobal to the linear triiodide anion, I₃^-, and represents the first example of a cluster made of three superatoms whose bonding characteristics are similar to those of a triatomic molecular species.