STRUCTURAL SYMMETRY ANALYSIS OF POSSIBLE ADDITION ELIMINATION AND ISOMERIC REARRANGEMENT MECHANISMS OF FULLERENES/

This work displays two-dimensional planar diagrams of three-dimensiona l fullerene cage clusters to clearly visualize the symmetrical arrange ments of the complete number of vertices (carbon atoms), edges (bonds) and faces (carbon rings) and to search for the possible isomeric rear rangement and addition/elimination reaction mechanisms. The reactionar y symmetry correlation is based on the choice of the common subgroup s ymmetry for the total reaction coordinate - the latter comes from the combination of multiple sets of local reaction coordinates over the pe riodic surface of the fullerene cage. The symmetric analysis also invo lves the determination of the number of symmetry-equivalent ways for s uch combinations to generate the total reaction coordinate. The symmet ry investigation also involves the hypothetical mechanisms for the add ition (and elimination) of two (diatomic) carbon atoms to (and from) t he reactant fullerene cage, to be followed by subsequent cooperative c age surface rearrangements over the cyclic boundaries to reach the str uctural symmetry of the final-product fullerene cage. The diagrams and isomeric rearrangement mechanisms elaborated are C-60(I-h, D-6h, C-3v , C-3, D-5), C-76(T-d, D-2, C-3) and C-84(T-d, C-3, C-3v). The additio ns and eliminations elaborated are C-26(D-3h) <-- C-28(T-d) --> C-30(D -5h), C-60(I-h) --> C-58(C-3v), and C-76(D-2) --> C-78(C-2v, D-3h) <-- C-80(D-5d)(b).