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 flash photolysis with 355 nm-laser excitation. NI derivatives are surrounded by H(2)O 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*(-)) is primarily generated via the quenching of (3)NI* by NI at the diffusion control rate. This intermolecular PET did not occur in aprotic CH(3)CN. The formation and decay times of NI*(-) showed strong dependence on the concentration of NI. Then, we suggest that NI*(-) could undergo proton abstraction to give ketyl radical species of NI [NI(H)*] in H(2)O/CH(3)CN.
Cho
Dae Won
DW
The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan. majima@saken.osaka-u.ac.jp
Fujitsuka
Mamoru
M
Yoon
Ung Chan
UC
Majima
Tetsuro
T
D004583:Electrons; D015394:Molecular Structure; D053644:Naphthalimides / Q000737:chemistry*; D010782:Photolysis; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D014867:Water / Q000737:chemistry
D053644:Naphthalimides; D012997:Solvents; D014867:Water