| Abstract | Photoinduced electron transfer and adduct formation between C60/C70 and 1,1¢-binaphthyl-2,2¢-diamine (BNA)
have been studied by nanosecond laser flash photolysis and steady-state photolysis as well as circular dichroism
measurements. Quantum yields (¼et
T) and rate constants of electron transfer from BNA to the excited triplet
state of C60/C70 have been determined by observing the transient absorption bands in the near-IR region
where the triplet states and anion radicals of fullerenes appear. Compared with the planar naphthylamine
moiety, ¼et
T values of perpendicular bichromophoric BNA are low because of hindrance of approach to
round fullerenes. The formation of an optically active adduct between C60 and BNA in a polar solvent was
observed upon excitation with light at ? > 330 nm where both C60 and BNA are light-absorbing. The reaction
mechanism for the optically active adduct formation can be explained as a result of the addition reaction of
the N-centered radical formed by deprotonation of BNA¥+, which is produced by direct photoejection. |