Synthesis of Open‐Cage Fullerene Derivatives Containing Multiple Hydroxyl and Amino Groups on the Rim of the Orifice†

Abstract

Comprehensive SummaryMost of the known open‐cage fullerene derivatives contain carbonyl and other relatively inert groups on the rim of the orifice. It is difficult to rationally design further reactions and attach other functional groups on to these open‐cage derivatives. In the present work, two molecules of difunctional 1,4‐benzenediamine have been incorporated into the rim of an open‐cage C60 derivative through one amino group leaving the other amino group free for further functionalization. The difunctional 4‐aminophenol reacted analogously to form an open‐cage derivative with a free OH group each on the two phenyl rings. The amino and hydroxyl groups on the phenyl ring above the rim of the orifice showed similar reactivity as aniline and phenol. One of the carbonyl groups on the rim of the orifice could be selectively reduced by NaBH4 and P(OEt)3. The reduction reactions were reversible and the reduced products could be readily converted back to the carbonyl precursor. Thus, this redox process acts as a tool to fine tune the size of the orifice for host‐guest studies.