ADDITION CHEMISTRY OF C-60 - A THEORETICAL-ANALYSIS OF SUBSTITUTIONAL PREFERENCES FOR HALOGENATION AND HYDROGENATION OF C-60

Reactions involving C-60 With a variety of species have produced a series of new fullerene derivatives. Such reactions include hydrogenation, methylation, halogenation, and epoxidation to name a few. The observed reaction chemistry traces the chemistry of aromatics in some cases; however, in others it is considerably less well understood. In this work, our efforts are directed at understanding mechanistic concerns in halogenation. To date several studies have analyzed the energetics of fluorination, bromination, and hydrogenation without serious consideration of orbital mechanism or isomer preferences. In this work, the orbital mechanism for reactivity is assessed for addition of halogens. The site preference for addition is analyzed with respect to symmetry distinct sites in C-60 These include the well-described 6-6' and 5-6' sites in C-60 The site directed preference for subsequent additions is discussed as well. Different site preferences are observed for F and Br; the effects are due to orbital driven reaction chemistry and thermodynamic stabilities of products. ''Ortho'' substitution appears favored for F substitution while 1,3 or 1,4 product predominants for Br addition.