COMBINED TOPOLOGICAL AND ENERGY ANALYSIS OF THE ANNEALING PROCESS IN FULLERENE FORMATION - STONE-WALES INTERCONVERSION PATHWAYS AMONG IPR ISOMERS OF HIGHER FULLERENES

An algorithm for finding all the possible products from consecutive ge neralized stone-Wales (GSW) rearrangements of any fullerene or closed cage precursor has been developed. Combined with energy-minimization, the program provides a versatile tool for the analysis of extremely co mplex interconversion pathways in the annealing process of fullerene f ormation. This paper presents results of the following preliminary app lications of the program: (1) identification of the shortest pathway f rom Wang's C-60 cage precursor to [60-I-h]fullerene, (2) availability of GSW cascades for a large number of sixty-carbon cage precursors lea ding to [60-I-h]fullerene, (3) generation of interconversion pathways among IPR isomers of higher [n]fullerenes (n = 78, 80, 82, 84, 90), an d (4) enumeration of fullerene isomers, The pathways map of [84]fuller ene solved the pending problem of why the high-energy isomer, [84-D-2d (I)]fullerene, has been detected using a helium-labelling technique in the product mixture and confirmed by IGOR calculation: this particula r isomer is the dead-end product of a downhill bypath.