Intermolecular photoinduced electron-transfer of 1,8-naphthalimides in protic polar solvents

The intermolecular photoinduced electron transfer (PET) processes of 1,8- naphthalimide (NI) derivatives including NI-linker-phenothiazine dyads were investigated in a protic H(2)O/CH(3)CN (v/ v = 1 : 1) solvent using ns-laser. ash photolysis with 355 nm-laser excitation. NI derivatives are surrounded by H2O in the ground state in H(2)O/CH(3)CN. The T(1)-T(n) absorption band of 3 NI* was observed at around 470 nm. The transient absorption band at around 410 nm increased concomitantly with the decay of (3)NI* in H(2)O/CH(3)CN. This implies that hydrated NI anion radical (NI(center dot-)) is primarily generated via the quenching of (3)NI* by NI at the di. usion control rate. This intermolecular PET did not occur in aprotic CH(3)CN. The formation and decay times of NI(center dot-) showed strong dependence on the concentration of NI. Then, we suggest that NI(center dot-) could undergo proton abstraction to give ketyl radical species of NI(center dot-) [NI(H)(center dot)] in H(2)O/CH(3)CN.