Properties and reactivity of xanthyl radical in the excited state.

The properties and reactivity of the 9-xanthyl radical (X(*)) in the doublet excited state (X(*)(D(1))) were investigated using nanosecond-picosecond two-color two-laser flash photolysis. The absorption and fluorescence spectra of X(*)(D(1)) were observed for the first time. The reactivity of X(*)(D(1)) toward a series of halogen donors and electron acceptors in acetonitrile and 1,2-dichloroethane (DCE) was investigated. It is confirmed that X(*)(D(1)) has a halogen abstraction ability from a series of halogen donors. On the basis of the solvent effect on the quenching rate constants of X(*)(D(1)), an electron transfer from X(*)(D(1)) to CCl(4) was indicated.