Icosahedral C sub 60: An aromatic molecule with a vanishingly small ring current magnetic susceptibility.

Recently Smalley and coworkers have produced evidence for the generation of C sub 60, which they formulated as a truncated icosahedron. Their suggestion that C sub 60 might provide the first example of a spheroidal aromatic molecule, has been amply supported by pi-electron and total energy calculations. A further suggestion by Smalley and coworkers which (in certain circumstances), also bears on the aromatic character of C sub 60 has yet to receive theoretical attention. They noted that: "The inner and outer surfaces are covered with a sea of pi electrons," and went on to suggest that: "... the chemical shift in the NMR of the central atom [placed in the interior] should be remarkable because of the ring currents." This intriguing hypothesis is the subject of the present paper.