Abstract:Functionalized fullerenes are known as a high-performance molecule. In this study, the alkyl-functionalized fullerenes (denoted by R-C 60 ) have been investigated by means of density functional theory (DFT) method to elucidate the effects of functionalization on the electronic states of fullerene. Also, the reaction mechanism of alkyl radical with C 60 was investigated. The methyl, ethyl, propyl and butyl radicals (denoted by n=1-4, where n means number of carbon atoms in alkyl radical) were examined as alkyl radicals. The DFT calculation showed that the alkyl radical binds to the carbon atom of C 60 in the on-top site, and a strong C-C single bond was formed. The binding energies of alkyl radicals to C 60 were distributed in the ranges 31.8-35.1 kcal mol -1 at the CAM-B3LYP/6-311G(d,p) level. It was found that the activation barrier exists before the alkyl addition: the barrier heights were calculated to be 2.1-2.8 kcal mol -1 . The electronic states of R-C 60 complex were discussed on the basis of theoretical results.