Generation of long-lived radical ions through enhanced photoinduced electron transfer processes between 60fullerene and phenothiazine derivatives

摘要

Photoinduced electron transfer processes between fullerenes (C60) and four phenothiazine derivatives (PTZs) in the absence and presence of hexylviologen dication (HV~(2+)) have been studied by the transient absorption method in the visible and near-IR regions.Electron-transfer takes place from PTZs to the -triplet states of fullerenes (3C60*) giving the radical anion of fullerenes (C60~(centre dot -)) and the radical cations of PTZs (PTZ~(centre dot +)).The rate constants and efficiencies of electron transfer are quite high,because of the high electron-donor abilities of PTZs as elucidated by their low oxidation potentials.On addition of HV~(2+) to the C60 and PTZ systems,the electron-mediating process occurs from C60~(centre dot +) to HV~(2+),yielding the viologen radical cation (HV~(centre dot +)).In the presence of a sacrificial donor,HV~(centre dot +) persisted for a long time.