title: Regioselective oxygenative tetraamination of [60]fullerene. Fullerene-mediated reduction of molecular oxygen by amine via ground state single electron transfer in dimethyl sulfoxide.
abstract: The reaction of [60]fullerene with a variety of a secondary aliphatic amines in 20% v/v dimethyl sulfoxide in chlorobenzene under an atmospheric pressure of molecular oxygen allows regioselective introduction of four amino groups and one epoxide group around one pentagon of the fullerene molecule in good to high yield. This new synthesis of tetraaminofullerene expoxide can be carried out with a simple procedure on a multigram scale at room temperature and affords a variety of functionalized fullerene derivatives. Near-infrared analysis of a mixture of [60]fullerene and piperidine in a deaerated dimethyl sulfoxide/chlorobenzene mixture indicated equilibrium formation of [60]fullerene radical anion (C60*-) that persists at least for 2 weeks at room temperature but reacts immediately with molecular oxygen to give the tetraaminofullerene expoxide. The Benesi-Hildebrand analysis of the concentration dependency of the near-infrared absorption indicated that a [C60*- piperidine*+] radical ion pair is formed with an equivalent constant of K = 0.62 +/- 0.02 M(-1) at 25 degrees C. This and other lines of evidence suggest that the oxygenative amination reaction involves C60-mediated reduction of molecular oxygen by the amine.
authors.affiliation: Department of Chemistry, ERATO (JST), The University of Tokyo, Hongo, Tokyo 113-0033, Japan. hisobe@chem.s.u-tokyo.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isobe
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Tanaka
authors.forename: Waka
authors.initials: W
authors.lastname: Nakanishi
authors.forename: Loïc
authors.initials: L
authors.lastname: Lemiègre
authors.forename: Eiichi
authors.initials: E
authors.lastname: Nakamura