[60]Fullerene anions in aqueous solutions (EPR study)

Photochemically and electrochemically reduced [60]fullerene encapsulated in γ-cyclodextrin ([60]fullerene/γ-CD) forms in aqueous solution four radical products (T, X, A, B) identified by EPR with the following g-values and peak-to-peak widths, pp: T: gT = 2.0015, ppT = 0.02 mT; X: gX = 2.0012, ppX = 0.028 mT; A: gA = 2.0000, ppA = 0.105 mT; B: gB = 2.0005, ppB = 0.05 mT. Radical A was also characterized with a near-IR band at 1085 nm, and assigned to [60]fullerene mono-anion, T to a [60]fullerene excited triplet state, X is possibly a primary mono-anion in the γ-CD superstructure, and B a di-anion or an associate form of mono-anion. Like radiolytic and flash photolytic studies, the retarded reduction of carboxylic derivatives suggests the formation of aggregates.