文摘
Fullerene skeleton modification has been investigated through selective cleavage of the fullerenecarbon-carbon bonds under mild conditions. Several cage-opened fullerene derivatives including three[59]fullerenones with an 18-membered-ring orifice and one [59]fullerenone with a 19-membered-ring orificehave been prepared starting from the fullerene mixed peroxide 1, C60(OOtBu)6. The prepositioned tert-butyl peroxy groups in 1 serve as excellent oxygen sources for formation of hydroxyl and carbonyl groups.The cage-opening reactions were initiated by photoinduced homolysis of the tBu-O bond, followed bysequential ring expansion steps. A key step of the ring expansion reactions is the oxidation of adjacentfullerene hydroxyl and amino groups by diacetoxyliodobenzene (DIB). Aminolysis of a cage-opened fullerenederivative containing an anhydride moiety resulted in multiple bond cleavage in one step. A dominomechanism was proposed for this reaction. Decarboxylation led to elimination of one carbon atom fromthe C60 cage and formation of [59]fullerenones. The cage-opened [59]fullerenones were found to encapsulatewater under mild conditions. All compounds were characterized by spectroscopic data. Single-crystalstructures were also obtained for five skeleton-modified derivatives including two water-encapsulatedfulleroids.