Iodine-Mediated Ring Enlargement in Fullerene Mixed Peroxides and Unexpected Alkoxylations of the Resulting Iodine-Containing Open-Cage Fullerenes

Iodine-mediated ring enlargement of the fullerene mixed peroxide C60(O)3(OAc)(OOtBu)3 affords iodine-containing open-cage fullerene C60(O)4(OAc)(I)(OOtBu)2 with a 15-membered orifice. Further modifications under acidic or basic conditions give derivatives with expanded or reshaped orifices. The iodo substituent remains intact under various conditions including reduction and oxidation. Single-crystal X-ray structures of key derivatives confirmed the cage architectures. Water encapsulation was observed in one derivative. These transformations demonstrate the unique reactivity of fullerene peroxides and provide a route to functionalized open-cage fullerenes as potential molecular containers.