Proton-Coupled Electron Transfer
Electron transfer (ET) and proton transfer (PT) are the two most fundamental chemical reactions. It has long been recognized that a great many ET reactions are associated with changes in protonation state. In general, this type of redox reaction is referred to as “proton-coupled electron transfer” or PCET. Original formulations of PCET reactions involved the transfer of a proton (H+) and an electron (e–) from one donor to one acceptor. At present, it is known that PCET reactions can take a variety of forms. A few examples of PCET reactions include processes in which a H+ and an e–transfer among one or more reactants in one or more kinetic steps; processes in which protons modulate ET, even if they do not transfer; and processes that involve multiple protons and/or...