作者:Peter Brough、Cedric Klumpp、Alberto Bianco、Stephane Campidelli、Maurizio Prato
DOI:10.1021/jo052388s
日期:2006.3.1
Eight members of a new family of fullerene derivatives, [60]fulleropyrrolidine-N-oxides, have been synthesized and characterized. Facile oxidation, by a peracid, of the parent [60]fulleropyrrolidine gave clean conversions into the product molecules, in which the tertiary amine is transformed into a quaternary amine bearing an oxygen atom. The reaction is very selective, favoring the nitrogen atom of the pyrrolidine ring in preference to epoxidation of the fullerene cage. The H-1 NMR shows an AB quartet splitting pattern, characteristic of nonequivalent hydrogens in the pyrrolidine ring and at a chemical shift displacement of 0.8 ppm downfield. Other methods of characterization are described, including MS, differential scanning calorimetry, thermogravimetric analysis, HPLC, UV/vis, and IR. Conclusive evidence for the formation of an N-oxide moiety is provided by the synthesis, oxidation, and NMR characterization of a novel [60]fulleropyrrolidine containing a N-15 isotope, showing an 85 ppm downfield heteroatom chemical shift. Preliminary details of the effects of substitution on the reactivity of the pyrrolidine ring are also reported.