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The Delocalization Index as an Electronic Aromaticity Criterion: Application to a Series of Planar Polycyclic Aromatic Hydrocarbons
Author(s) -
Poater Jordi,
Fradera Xavier,
Duran Miquel,
Solà Miquel
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200390041
Subject(s) - aromaticity , delocalized electron , electron delocalization , chemistry , ring (chemistry) , computational chemistry , planar , molecule , organic chemistry , computer science , computer graphics (images)
This work introduces a new local aromaticity measure, defined as the mean of Bader's electron delocalization index (DI) of para ‐related carbon atoms in six‐membered rings. This new electronic criterion of aromaticity is based on the fact that aromaticity is related to the cyclic delocalized distribution of π‐electrons. We have found that this DI and the harmonic oscillator model of aromaticity (HOMA) index are strongly correlated for a series of six‐membered rings in eleven planar polycyclic aromatic hydrocarbons. The correlation between the DI and the nucleus‐independent chemical shift (NICS) values is less remarkable, although in general six‐membered rings with larger DI values also have more negative NICS indices. We have shown that this index can also be applied, with some modifications, to study of the aromaticity in five‐membered rings.