Chapter Nine – Calculating the Aromaticity of Heterocycles
Halina Szatyłowicz , Olga Stasyuk , Tadeusz Marek Krygowski
AbstractHeterocycles play a very important role in chemistry, biochemistry, pharmacy, and related fields; therefore, the ability to describe their π-electron delocalization is essential. The description and the application of the most effective and popular aromaticity indices based on energetic, structural, magnetic as well as electronic properties are presented herein for heterocycles. A multidimensional character of aromaticity has again been confirmed for five- and six-membered heterocyclic rings and for their fused systems indicating that utilization of one index only cannot be sufficient for the estimation of the aromatic character of a given system. In turn, the usefulness of the Kohonen neuron networks for the classification of the π-electron cyclic systems into three sets, namely aromatic, nonaromatic, and antiaromatic, has been shown. Although for all these groups some linear correlations between various aromaticity descriptors may exist, for each separated subgroup these relationships fail.
|Publication size in sheets||1.3|
|Book||Scriven Eric F.V, Ramsden Christopher A. (eds.): Advances in Heterocyclic Chemistry, vol. 120, 2016, Elsevier, ISBN 9780128052488, 364 p.|
|Keywords in English||Aromatic character; Aromaticity indices; Azine; Azole; Heterocycles; Nucleobases; Pyridine; Pyrrole; Tautomers; Thiophene|
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