Competitive Marcus-Type Electron Transfer and Energy Transfer from the Higher Triplet Excited State

Electron transfer (ELT) and energy transfer (ENT) from the higher excited triplet state (T n ) ( n > 1) of various naphthalene derivatives (NpDs) to some polychlorobenzenes (CBs) such as chlorobenzene, 1,4-dichlorobenzene, and 1,2,4-trichlorobenzene were examined. It is confirmed that the ELT process from the NpDs (T n ) to CBs obeys Marcus's theory from the driving force dependence of the ELT yield. This is the first example of the Marcus-type ELT from the T n state. As a competitive process of the ELT, the ENT from NpDs (T n ) to CBs giving the higher excited state of CBs (T n ) (NpD (T n ) + CB (S 0 ) → NpD (S 0 ) + CB (T n )) was observed although a part of CBs (T n ) decomposed by the C−Cl bond dissociation giving chlorocyclohexadienyl radical and chloride radical. This is also the first example of intermolecular ENT from molecules in the T n state to quenchers giving the quenchers in the T n state.