PREPARATION AND CHARACTERIZATION OF FULLEROID AND METHANOFULLERENE DERIVATIVES

We describe the synthesis and complete characterization of soluble der ivatives of C-60 for applications to physics and biology. The goal of the strategy was to have a ''modular'' approach in order to be able to easily vary a functional group attached indirectly to the cluster. Th e functionality could be hydrophilic (e.g., histamide) or hydrophobic (e.g., cholestanoxy). The former was prepared for biological studies a nd the latter for photophysical studies toward improvement of photoind uced electron transfer efficiencies in the fabrication of photodetecto rs and photodiodes. An important intermediate, a carboxylic acid, was found to be recalcitrant to characterization by the usual mass spectro scopic and elemental analysis techniques. This problem was solved by t he use of MALDIMS. The carboxylic acid was easily converted to the key intermediate acid chloride, which in turn was convertible to a large variety of derivatives. Both isomeric forms ([5,6], fulleroid and [6,6 ], methanofullerene) of the C-61 clusters were prepared. The fulleroid formation could have given rise to a 50:50 mixture of phenyl-over-for mer pentagon phenyl-over-former hexagon isomers but, remarkably, affor ded a 95:5 mixture of these isomers, respectively. The fulleroid and m ethano-fullerene gave different cyclic voltammograms, with the former being reduced at 34 mV more positive potential than the latter.