ARE KEKULENE, CORONENE, AND CORANNULENE TETRAANION SUPERAROMATIC - THEORETICAL-EXAMINATION USING HARDNESS INDEXES

The superaromaticity concept is examined and developed, taking into ac count what is known about aromaticity. Three new hardness indices are defined, and shown to be excellent parameters for characterizing super aromaticity. High superaromaticity indicates significant global annule noid conjugation relative to local benzenoid conjugation in circularly annealed benzenoid molecules. Kekulene, coronene and corannulene tetr aanion all are predicted to be superaromatic. The prediction for the c orannulene tetraanion strongly supports the 'annulene-within-an-annule ne' structure derived from NMR data.