Chemistry of the Fullerenes: The Manifestation of Strain in a Class of Continuous Aromatic Molecules

Within the π-orbital axis vector theory, the total rehybridization required for closure of the fullerenes is approximately conserved. This result allows the development of a structure-based index of strain in the fullerenes, and it is estimated that about 80 percent of the heat of formation of the carbon atoms in C 60 may be attributed to a combination of σ strain and steric inhibition of resonance. Application of this analysis to the geometries of structurally characterized organometallic derivatives of C 60 and C 70 shows that the reactivity exhibited by the fullerenes may be attributed to the relief of a combination of local and global strain energy. C 60 is of ambiguous aromatic character with anomalous magnetic properties but with the reactivity of a continuous aromatic molecule, moderated only by the tremendous strain inherent in the spheroidal structure.