title: Proton-Coupled Electron Transfer in the Reduction of Carbonyls by Samarium Diiodide-Water Complexes.
abstract: Reduction of carbonyls by SmI2 is significantly impacted by the presence of water, but the fundamental step(s) of initial transfer of a formal hydrogen atom from the SmI2-water reagent system to produce an intermediate radical is not fully understood. In this work, we provide evidence consistent with the reduction of carbonyls by SmI2-water proceeding through proton-coupled electron transfer (PCET). Combined rate and computational studies show that a model aldehyde and ketone are likely reduced through an asynchronous PCET, whereas reduction of a representative lactone occurs through a concerted PCET. In the latter case, concerted PCET is likely a consequence of significantly endergonic initial electron transfer.
authors.affiliation: Department of Chemistry, Lehigh University , 6 E. Packer Avenue, Bethlehem, Pennsylvania 18015, United States.
authors.forename: Tesia V
authors.initials: TV
authors.lastname: Chciuk
authors.affiliation: Department of Chemistry, Lehigh University , 6 E. Packer Avenue, Bethlehem, Pennsylvania 18015, United States.
authors.forename: William R
authors.initials: WR
authors.lastname: Anderson
authors.affiliation: Department of Chemistry, Lehigh University , 6 E. Packer Avenue, Bethlehem, Pennsylvania 18015, United States.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Flowers