Concerted and Stepwise Proton-Coupled Electron Transfer for Tryptophan-Derivative Oxidation with Water as the Primary Proton Acceptor: Clarifying a Controversy
Astrid Nilsen-Moe, Andrea Rosichini, Starla D. Glover, Leif Hammarström
Abstract
O) as the proton acceptor. The observed rate constants are up to more than 100 times higher than those measured for initial electron transfer, excluding the electron-first mechanism. Instead, the reaction can be attributed to CEPT. These conclusions are important for our view of CEPT in water and of PCET-mediated radical reactions with solvent-exposed tryptophan in natural systems.
Topics & Concepts
ChemistryProton-coupled electron transferElectron transferPhotochemistryReaction rate constantProtonRadical ionRedoxIndole testKinetic isotope effectElectron acceptorQuenching (fluorescence)AcceptorStereochemistryKineticsInorganic chemistryFluorescenceOrganic chemistryDeuteriumPhysicsIonCondensed matter physicsQuantum mechanicsMetal-Catalyzed Oxygenation MechanismsPhotochemistry and Electron Transfer StudiesPorphyrin and Phthalocyanine Chemistry