Expanding the chemistry of stable trinuclear all-metal aromatics

Abstract

Aromaticity is a fascinating concept that rationalizes the bonding of an intriguing class of organics. Suitably delocalized metal-metal bonds can stabilize a particular class of discrete trinuclear complexes that are the transition-metal counterparts of carbon-based aromatic compounds. However, experimental applications are still rare since in most cases their stability is limited. Our research group developed a simple synthetic method to obtain a family of bench-stable trinuclear clusters of palladium and platinum with a straightforward synthetic route. These noble-metal analogues of the cyclopropenyl cation show a great versatility since they found applications in both catalysis and coordination chemistry. They proved to be able to semi-reduce internal alkynes with complete selectivity. Thanks to their peculiar bonding mode, these cationic complexes can mimic regular aromatics acting as donor ligands for Lewis acidic cations. Complementary efforts to deepen the comprehension of factors governing the formation of all-metal aromatic complexes ended up finding a new synthetic strategy to afford mixed metal clusters.