Photochemical Oxygen-Atom-Transfer Reactivity of Platinum(II) Peroxycarbonates

Peroxycarbonate (CO₄ ^2-) is implicated in various biological, catalytic, and energy storage processes - despite the capability of transition metals to guide the reactivity of this unstable intermediate toward productive ends, the coordination chemistry of metal-peroxycarbonate complexes, M(CO₄), remains poorly understood. Herein, we describe the synthesis, isolation, and structural characterization of two platinum(II) peroxycarbonate complexes Pt(PPh₃)₂(CO₄) (1) and Pt(dppe)(CO₄) (2) (dppe = 1,2-bis(diphenylphosphino)ethane). Whereas the complexes are thermally stable, they react by oxygen-atom transfer (OAT) when irradiated with visible light. This photoreactivity was investigated using NMR and FT-IR photolysis to identify structures of reaction intermediates and photoproducts, together with kinetic analyses, which establish unimolecular OAT from the CO₄ ^2- ligand to the bound phosphine. In addition to providing rare examples of structurally characterized M(CO₄) complexes, this work is the first demonstration of photochemical reactivity in a peroxycarbonate complex.