Electron Transfer Studies in C78 (C2v‘), C76 (D2), C70 (D5h), and C60 (Ih) Surfactant Aqueous Solutions

Abstract

C60 (Ih) and several higher fullerenes, namely, C70 (D5h), C76 (D2), and C78 (C2v‘), have been solubilized via capping with suitable surfactants. Excited states and reduced states of these surfactant systems were probed by photolytic and radiolytic techniques. Flash photolytic irradiation at 355 nm of surfactant solutions of C60, C70, C76, and C78 revealed the rapid grow-in of transient (*S1 → *Sn) absorptions with λmax at 920, 660, 650, and 890 nm, respectively. The associated intersystem crossing rates to the energetically lower lying excited triplet states are typically on the order of 9.0 × 108 s-1. Reductive quenching of the excited triplet states by diazabicyclooctane (DABCO) occurs with (0.8−7.4) × 107 M-1 s-1 and yields the fullerene π-radical anions. Direct reduction of surfactant capped fullerene monomers have been studied by means of time-resolved pulse radiolysis with measurements being conducted in the near-IR region. Radiolytic reduction of (C76)surfactant and (C78)surfactant resulted in the...