Photoinduced Electron Transfer between C₆₀/C₇₀ and Zinc Tetraphenylporphyrin in Polar Solvents

Photoinduced electron transfer between C 60 /C 70 and zinc tetraphenylporphyrin (ZnTPP) in a polar solvent has been investigated with a nanosecond laser photolysis method by observing the transient absorption bands in the near-IR region. The transient absorption bands of the C 60 /C 70 radical anion (C 60 •- /C 70 •- ) in the near-IR region gave evidence of electron transfer for the system ZnTPP and C 60 /C 70 . In ZnTPP solution where C 60 and C 70 were photoexcited predominantly, electron transfer takes place from the ground state of ZnTPP to the triplet states of C 60 /C 70 ( 3 C 60 */ 3 C 70 *). In the concentrated ZnTPP solution where ZnTPP was predominantly photoexcited, the triplet state of ZnTPP donates the electron to the ground state of C 60 /C 70, producing C 60 •- /C 70 •- . The efficiency of electron transfer via the 3 C 60 */ 3 C 70 * route is higher than that via 3 ZnTPP*.