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-tiichlorobenzene were examined. It is confirmed that the ELT process from the NpDs (T) 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 froth the T state. As a competitive process of the ELT, the ENT from NpDs (T) to CBs giving the higher excited state of CBs (T) (NpD (T-n) + CB (S-0) --> NpD (S-0) + CB (T-n)) was observed although a part of CBs (T) decomposed by the C-Cl bond dissociation giving chorocyclohexadienyl radical and chloride radical. This is also the first example of intermolecular ENT from molecules in the T state to quenchers giving the quenchers in the T-n state.