Electron Transfer in Nonpolar Solvents in Fullerodendrimers with Peripheral Ferrocene Units

Two new fullerodendrimers, with two and four ferrocene units on their periphery, have been synthesized by 1,3-dipolar cycloaddition reactions between the corresponding azomethine ylides and C60. These new compounds have been studied by using cyclic vol- tammetry and UV/Vis spectroscopy. Weak intramolecular interactions be- tween the fullerene cage and the ferro- cene groups have been found. The pho- tochemical events of both fullerene- ferrocene dendrimers have been probed by means of steady-state and time-resolved techniques. The steady- state emission intensities of the fullero- pyrrolidine-ferrocene dendrimers 1 and 2 were found to be quenched rela- tive to the N-methylfulleropyrrolidine without substituents that was used as a model. The nanosecond transient ab- sorption spectral studies revealed effi- cient charge separation in both systems, even in toluene. The lifetimes of the (C60)C � -(dendron)C + are higher for the second-generation fullerodendrimer (with four ferrocene units) and they are of the order of tens of nanoseconds in toluene and hundreds of nanosec- onds in polar solvents.