ELECTROCHEMICAL PROPERTIES OF FULLERENES AND FULERENE DERIVATIVES: A POSSIBLE ROUTE TO ENDOHEDRAL COMPLEXES

An overview of the redox chemistry of the fullerenes, starting with that of C60 and going on to that of some of its derivatives, is presented. The main focus revolves around the cathodic electrochemistry of C60 in homogeneous solution as well as of some of its derivatives at very negative potentials. Potentials as negative as -3.3 V vs the ferrocene/ferricinium (Fc/Fc+) couple are reported. While underivatized C60 and C70 can be reversibly reduced to their corresponding hexaanions, their derivatives exhibit chemical reactions following their fourth electrochemical reduction. The results for some derivatives are interpreted in terms of chemical reactions that lead to the formation of stable diphenyl carbanions. During these reactions, it is proposed that a “hole” is opened on the C60 sphere, and thus the process is envisioned as a potential preparative method for endohedral cation complexes.