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Four fullerosteroidal conjugates, previously confirmed to express two-to threefold better antioxidant activity in vitro than C 60 , were subjected to additional studies, including electrochemical, theoretical, and morphological examination. All tested compounds underwent reversible, diffusion-controlled reductions. A notable influence of the solvent properties on the reduction potential, the level of aggregation, and the lowest unoccupied molecular orbital (LUMO) energy was observed. Theoretical calculations indicated that the energy gain obtained by an intermediate formation, together with compounds' polarizability, polarity, and lipophilicity contributed to the radical quenching capacity. Very large supramolecular aggregates of all fullerosteroidal esters with no hierarchical arrangement were observed in precipitated samples, while solvent induced self-assembling led to round nanoplates, which further arranged to flowershaped hierarchically ordered architectures or uniformly distributed discoid particles. As in electrochemical studies, fine tuning of the aggregation level was achieved by the solvent.

SummaryThe potential use of amphiphilic fullerene derivatives as a bionanomaterial was investigated by cyclic voltammetry (CV), scanning electron microscopy (SEM), and the ferrous ion oxidation–xylenol orange (FOX) method. Despite the disrupted delocalization of the π-electronic system over the C60 sphere, its antioxidant capacity remained high for all twelve derivatives. The compounds expressed up to two-fold and 5–12-fold better peroxide quenching capacity as compared to pristine C60 and standard antioxidant vitamin C, respectively. During precipitation and slow evaporation of the solvent, all compounds underwent spontaneous self-assembly giving ordered structures. The size and morphology of the resulting particles depend primarily on the sample concentration, and somewhat on the side chain structure.

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