Monomeric Chini-Type Triplatinum Clusters Featuring Dianionic and Radical-Anionic π*-Systems.

Owing to their unique topologies and abilities to self-assemble into a variety of extended and aggregated structures, the binary platinum carbonyl clusters [Pt3 (CO)6 ]n (2-) ("Chini clusters") continue to draw significant interest. Herein, we report the isolation and structural characterization of the trinuclear electron-transfer series [Pt3 (μ-CO)3 (CNAr(Dipp2) )3 ](n-) (n=0, 1, 2), which represents a unique set of monomeric Pt3 clusters supported by π-acidic ligands. Spectroscopic, computational, and synthetic investigations demonstrate that the highest-occupied molecular orbitals of the mono- and dianionic clusters consist of a combined π*-framework of the CO and CNAr(Dipp2) ligands, with negligible Pt character. Accordingly, this study provides precedent for an ensemble of carbonyl and isocyanide ligands to function in a redox non-innocent manner.