Pages 236-241 J. Aihara, Spherical Aromaticity in Charged Fullerenes and the 2(N + 1) 2 Rule

Jun-Ichi Aihara, Jun-Ichi Aihara
2002 J. Aihara Internet Electronic Journal of Molecular Design   unpublished
Motivation. Fullerene has a large negative NICS value at the cage center when its shells are filled with 2(N + 1) 2 electrons. Here, N is an arbitrary positive integer. However, it still seemed uncertain whether or not such a NICS value indicates spherical aromaticity. Method. The TREs calculated for neutral and charged fullerenes with 2(N + 1) 2-electrons were compared with the NICS values at their cage centers. Results. Many such fullerene cages were found to have large negative TREs,
more » ... ng that diatropicity at the cage center does not always represent aromaticity. Conclusions. Pronounced diatropicity at the cage center must arise mainly from large circuits in the cage, whereas relatively small circuits must be responsible for large part of aromatic stabilization. Abbreviations and notations NICS, nucleus-independent chemical shift (endo), nucleus-independent chemical shift at the cage center TRE, topological resonance energy %TRE, percentage topological resonance energy