Molecular electrochemistry of hydrofullerenes C70H36-46

Electrochemistry of a mixture of hydrofullerenes C70H36-46 composed of C70H 36, CH70H38, C70H44, and C70H46 (50, 20, 14, and 15%, respectively) was stu died by cyclic voltammetry in THF and CH2Cl2 in the -43--13 degreesC temper ature range. Two cathodic peaks, namely, one-electron reversible (E degrees = -3.16 V (Fc(0/+)), Fc is ferrocene) and irreversible (E-p(c) = -3.37 V ( Fc(0/+))) were observed for this mixture in THF. The irreversible broad oxi dation peak (E-p(a) = 1.22 V (Fc(0/+))) was observed in CH2Cl2. The reversi ble reduction peak (E degrees = -3.16 V) and irreversible oxidation peak (E -p(a) = 1.22 V) were attributed to the most stable hydrofullerene C70H36. T he irreversible reduction (E-p(c) = -3.37 V) and oxidation (E-p(a) = 1.22 V ) peaks were attributed to hydrofullerenes C70H44-46 with a higher degree o f 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 C70H44-4 6, respectively, and indicate that these hydrofullerenes are sufficiently " hard" molecules with low reactivity in redox reactions.