The time resolved transient absorption property, kinetics and mechanism of electron transfer(ET) process of the fluorescence probe, N-(2-hydroxyethyl)-1,8-naphthalimide(NPI) were studied. The transient absorption spectra of NPI in H 2O-CH 3CN solution were successfully detected upon pulsed excitation at 355 nm. 3NPI was proved as the primary excited state with lifetime of 147 μs. 3NPI underwent the T-T energy transfer with β-carotene and ET with triphenyl amine to produce NPI -·. In the absence of quenchers, the self-quenching of 3NPI by the ground states of NPI took place via ET. The ET from nucleosides to 3NPI was also explored. NPI showed a strong electron-accepting capability and the absorbance of 3NPI was strongly quenched by the nucleosides. The formation of NPI -· was facilitated to a great extent simultaneously. The bimolecular quenching rate constants of NPI by GUA and DGUA were determined as k 3=8.8×106 mol -1·L·s -1, k 4=2.1×107 mol·L·s -1. The ET between NPI and nucleosides was verified and the mechanism was proposed.
