Photoprocesses associated
with the complexation of a pyridinefunctionalized
C60 fullerene derivative
to ruthenium- and zinc-tetraphenylporphyrins
(tpp) have been studied by timeresolved
optical and transient EPR
spectroscopies. It has been found that
upon irradiation in toluene, a highly
efficient triplet ± triplet energy transfer
governs the deactivation of the photoexcited
[Ru(tpp)], while electron transfer
(ET) from the porphyrin to the
fullerene prevails in polar solvents.
Complexation of [Zn(tpp)] by the fullerene
derivative is reversible and, following
excitation of the [Zn(tpp)], gives
rise to very efficient charge separation.
In fluid polar solvents such as THF and
benzonitrile, radical-ion pairs (RPs) are
generated both by intramolecular ET
inside the complex and by intermolecular
ET in the uncomplexed form.
Charge-separated states have lifetimes
of about 10 ms in THF and several
hundred of microseconds in benzonitrile
at room temperature.
