title: Effects of proton acceptors on formation of a non-heme iron(IV)-oxo complex via proton-coupled electron transfer.
abstract: Rates of formation of a non-heme iron(IV)-oxo complex, [Fe(IV)(O)(N4Py)](2+) (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), via electron-transfer oxidation of [Fe(III)(OH)(N4Py)](2+) in acetonitrile (MeCN) containing H2O (0.56 M) were accelerated as much as 390-fold by addition of proton acceptors such as CF3COO(-), TsO(-) (p-MeC6H4SO3(-)), NsO(-) (o-NO2C6H4SO3(-)), DNsO(-) (2,4-(NO2)2C6H3SO3(-)), and TfO(-) (CF3SO3(-)). The acceleration effect of proton acceptors increases with increasing basicity of the proton acceptors. The one-electron oxidation potential of [Fe(III)(OH)(N4Py)](2+) was shifted from 1.24 to 0.96 V vs SCE in the presence of TsO(-) (10 mM). The electron-transfer oxidation of Fe(III)-OH complex was coupled with the deprotonation process by proton acceptors in which deuterium kinetic isotope effects were observed when H2O was replaced by D2O.
authors: Department of Material and Life Science, Graduate School of Engineering, Osaka University, ALCA, Japan Science and Technology, Suita, Osaka 565-0871, Japan.
authors: Yusuke
authors: Y
authors: Nishida
authors: Yuma
authors: Y
authors: Morimoto
authors: Yong-Min
authors: YM
authors: Lee
authors: Wonwoo
authors: W
authors: Nam
authors: Shunichi
authors: S
authors: Fukuzumi
mesh_terms: D004579:Electron Transport; D006418:Heme / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D011522:Protons
chemical_list: D011522:Protons; D006418:Heme; D007501:Iron