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Quantification of Aromaticity in Oxocarbons: The Problem of the Fictitious “Nonaromatic” Reference System
Author(s) -
Quiñonero David,
Garau Carolina,
Frontera Antonio,
Ballester Pablo,
Costa Antonio,
Deyà Pere M.
Publication year - 2002
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 - 10.1002/1521-3765(20020118)8:2<433::aid-chem433>3.0.co;2-t
Subject(s) - aromaticity , electronegativity , chemistry , computational chemistry , property (philosophy) , molecule , organic chemistry , epistemology , philosophy
Despite the extensive research reported in the literature, the concept of aromaticity has eluded rigorous quantification. The main reason for this undesirable reality is the fact that aromaticity is a differential property. While bond orders, atomic charges and electronegativity differences are properties of the molecule under analysis, the aromaticity concept often refers to the difference between some property of the molecule and that of an artificial “nonaromatic” reference system. A rigorous definition of such a reference system is non‐existing and therefore constituting the main barrier to obtain a satisfactory quantification of the aromatic concept. Oxocarbon acids and their anions are examples where the criteria of aromaticity that use reference systems are unsuccessful, only NICS criterion gives satisfactory results. Wiberg bond indexes and 17 O NMR chemical shifts are also useful to study such compounds.