Electronic structure of the fulleroids: Homoconjugation in bridged C-60 derivatives

The electronic structure of the fulleroids is examined with the pi-orbital axis vector (POAV) analysis and 3D-HMO theory. Using ab initio HF geometries, we compare the electronic structure of fulleroids with bridge groups attached to [5,6]- and [6,6]-bonds in C-60, with the well known bridged annulenes: 1,6-methano[10]annulene, 1,5-methano[10]annulene, and 1,4,7-methino[10]annulene. Although the perimeters of these systems are structurally related, the greater pyramidalization implicit in the fulleroid structure substantially modified their electronic structure. (C) 1996 Elsevier Science Ltd.