Efficient charge separation in porphyrin-fullerene-ligand complexes.
Photoprocesses associated with the complexation of a pyridine-functionalized C60 fullerene derivative to ruthenium- and zinc-tetraphenylporphyrins (tpp) have been studied by time-resolved 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 micros in THF and several hundred of microseconds in benzonitrile at room temperature.
Da Ros
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T
Dipartimento di Scienze Farmaceutiche, Università di Trieste, Italy.
Prato
M
M
Guldi
D M
DM
Ruzzi
M
M
Pasimeni
L
L
D002244:Carbon / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D037741:Fullerenes; D007477:Ions; D007700:Kinetics; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
D037741:Fullerenes; D007477:Ions; D011166:Porphyrins; D002244:Carbon; C069837:fullerene C60