| Since the discovery and isolation of macroscopic quantities of the fullerenes, the preparation of derivatives has grown rapidly over the last few years. Due to its poor electron delocalization, C60 does not act as an aromatic compound as originally expected. It undergoes reactions in the some manner as electron deficient alkenes, such as nucleophilic addition, radical addition, and cycloaddition. Functionalization of C60 in our group has been done primarily by cycloaddition reactions; in particular the 1,3-dipolar addition of diazoalkanes and alkyl azides.; The most fascinating properties of C60 are its structural and electronic properties. For biological applications its shape has been shown to be used for molecular recognition for the inhibition of HIVP. Here is described the synthesis and virology studies of a soluble fullerene derivative. This derivative was prepared through the addition of a diazaoalkane to C 60.; Unlike the addition of a second equivalent of diazoalkane to C60 , which does not show marked selectivity, the addition of azides to C60 shows chemo and regio selectivity. Utilization of this unique selectivity, led us to the preparation of the first heterofullerene "C59N" in bulk quantity: Upon developing an understanding of its mechanism of formation, we introduced methodology that opens a viable route to the Functionalization of azafullerenes. A combination of 13C and 15N-coupled 13C NMR experiments of various azafullerenes, provided unequivocal proof of the azafullerene structure and provides a useful tool for the characterization of future azafullerene derivatives. Also described is the application of this procedure for the formation of higher heterofullerene analogs, i.e. the selective synthesis of various "C69N" isomers.; In conclusion, a general synthesis of azafullerenes has been discovered, which can be summarized as: FULLERENE → ASAFULLEROID → HOLEYBALL → AZAFULLERENE... |
