Molecular electrochemistry of hydrofullerenes C70H36—46

Abstract

Electrochemistry of a mixture of hydrofullerenes C70H36—46 composed of C70H36, C70H38, C70H44, and C70H46 (50, 20, 14, and 15%, respectively) was studied by cyclic voltammetry in THF and CH2Cl2 in the –43—–13 °C temperature range. Two cathodic peaks, namely, one-electron reversible (E° = –3.16 V (Fc0/+), Fc is ferrocene) and irreversible (Ep = –3.37 V (Fc0/+)) were observed for this mixture in THF. The irreversible broad oxidation peak (Ep = 1.22 V (Fc0/+)) was observed in CH2Cl2. The reversible reduction peak (E° = –3.16 V) and irreversible oxidation peak (Ep = 1.22 V) were attributed to the most stable hydrofullerene C70H36. The irreversible reduction (Ep = –3.37 V) and oxidation (Ep = 1.22 V) peaks were attributed to hydrofullerenes C70H44—46 with a higher degree of hydrogenation. The values of an “electrochemical gap,” which is an analog of the energy gap (HOMO—LUMO), are 4.38 and 4.59 V for C70H36 and C70H44—46, respectively, and indicate that these hydrofullerenes are sufficiently “hard” molecules with low reactivity in redox reactions.