Abstract :
Summary form only given. Electrochemical measurements have been done on the pure metallofullerene La@C/sub 82/ for the first time. Five reversible reduction and one reversible oxidation processes were observed by cyclic, differential pulse, and Osteryoung square wave voltammetrys. The first reversible oxidation potential is approximately equal to that of ferrocene, indicating that La@C/sub 82/ is a moderate electron donor and therefore an oxygen-stable molecule. In addition, La@C/sub 82/ is a stronger electron acceptor than empty fullerenes such as C/sub 60/, C/sub 70/, C/sub 76/, and C/sub 84/. A comparative electrochemical study is presented on organofullerenes derivatized with oxygen-, carbon-, and silicon-containing groups. Electron affinities of the organofullerenes increase with increasing electronegativities of the attached atoms. In the carbon-derivatized C/sub 60/, hybridization of the attached carbon atoms and electron-withdrawing groups also affect their reduction potentials. Electron-donating groups, such as alkyl and silyl, significantly lower the oxidation potentials of the organofullerenes.
