Chalcogen Atoms as Electron Donors in Proton-Coupled Electron Transfer Reactions

Proton-coupled electron transfer (PCET) reactions are crucial for the optimal functioning of a broad scope of chemical and biological processes. In this report, we present an unprecedented type of concerted PCET (cPCET), in which a chalcogen atom acts as the electron donor. The nature of this mechanism is key for understanding the reactivity of different radical trapping antioxidants having heavy chalcogens (S, Se, or Te) in their structures. Moreover, this chalcogen-assisted cPCET is likely to be occurring in multiple systems of biological interest.