Electrochemical Properties of Soluble Fullerene Derivatives

The family of fullerene derivatives obtained by 1,3-dipolar cycloaddition of azomethine ylides to C60 is colloquially termed fulleropyrrolidines. In this paper, we report the synthesis and the electrochemical properties of a series of fulleropyrrolidine derivatives. All compounds are characterized by the presence of a solubilizing mTEG group. In addition, a derivative containing a thiophene moiety, covalently attached to the pyrrolidine ring has been studied. Cyclic voltammetry measurements, performed also at low temperatures, allowed the observation of five fullerene-centered reductions for all the species. Adsorption phenomena, however, were found associated to the last reduction processes in the thiophene–fulleropyrrolidine conjugate. Moreover, thanks to the increased solubility of the latter species in polar solvents (acetonitrile–dichloromethane mixtures) its anodic polymerization was carried out, leading to a conducting film still retaining the redox properties of the fullerene derivative.