title: Photo- and radiation-chemical formation and electrophilic and electron transfer reactivities of enolether radical cations in aqueous solution.
abstract: In aqueous solution, enolether radical cations (EE.+) were generated by photoionization (lambda < or = 222 nm) or by electron transfer to radiation-chemically produced oxidizing radicals. Like other radical cations, the EE.+ exhibit electrophilic reactivity with respect to nucleophiles such as water or phosphate as well as electron transfer reactivity, for example, towards one-electron reductants such as phenols, amines, vitamins C and E, and guanine nucleosides. The reactivity of these electron donors with the radical cation of cis-1,2-dimethoxyethene.+ (DME.+) can be described by the Marcus equation with the reorganization energy lambda = 16.5 kcalmol(-1). By equilibrating DME.+ with the redox standard 1,2,4-trimethoxybenzene, the reduction potential of DME.+ is determined to be 1.08 +/- 0.02 V/NHE. The oxidizing power of the radical cation of 2,3-dihydrofuran, which can be considered a model for the enolether formed on strand breakage of DNA, is estimated to be in the range 1.27-1.44 V/NHE.
authors.affiliation: Max-Planck-Institut für Strahlenchemie, Mülheim, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Bernhard
authors.forename: J
authors.initials: J
authors.lastname: Geimer
authors.forename: M
authors.initials: M
authors.lastname: Canle-Lopez
authors.forename: J
authors.initials: J
authors.lastname: Reynisson
authors.forename: D
authors.initials: D
authors.lastname: Beckert
authors.forename: R
authors.initials: R
authors.lastname: Gleiter
authors.forename: S
authors.initials: S
authors.lastname: Steenken