화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.119, No.20, 4972-4982, 2015
Local Aromaticity in Naphtho-Annelated Fluoranthenes: Can the Five-Membered Rings Be More Aromatic Than the Six-Membered Rings?
All Kekule-structure-based theories predict that the central five-membered ring in fluoranthene and naphtho-annelated fluoranthenes is nonaromatic. In the present work, a detailed study of the local aromaticity in a series of naphtho-annelated fluoranthene derivatives was performed by means of the following aromaticity indices: the energy effect (ef), bond resonance energy (BRE), multicenter delocalization indices (MCI), harmonic oscillator model of aromaticity (HOMA) index, nucleus-independent chemical shifts (NICS), and ring current maps. It was found that, according to the ef, BRE, MCI, and HOMA values, the pentagonal rings in some naphtho-annelated fluoranthenes can be even more aromatic than some hexagonal rings in the respective molecules. The magnetic indices do not support the results obtained by the energetic, electron delocalization, and geometrical aromaticity indices.