Boron-Centered Proton-Coupled Electron Transfer

Proton-Coupled Electron Transfer (PCET) has been well-established in transition metal complexes, biomolecules, and organic compounds. In the majority of PCET reagent systems, hydrogen-atom equivalents are toggled predominantly at transition-metal centers or at heteroatomcontaining basic sites, most commonly amines, hydroxyl groups, or phosphines, where welldefined X-H bonds (X = N, O, P, or metal hydrides) provide the thermodynamic and kinetic framework for coupled proton-electron transfer. In this work, we demonstrate that a deliberately designed perfunctionalized redox-active boron cluster ( closo -B 6 Ph 6 2- ) can intrinsically mediate PCET, with the coupled proton and electron transfer events confined exclusively to boron atoms rather than being mediated by metals or heteroatom based functional groups, thereby representing the first unequivocal example of a purely boron-centered PCET process.