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Substituent effect on local aromaticity in mono and di‐substituted heterocyclic analogs of naphthalene
Author(s) -
Mohajeri Afshan,
Shahamirian Mozhgan
Publication year - 2010
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1619
Subject(s) - aromaticity , chemistry , substituent , heteroatom , quinoline , delocalized electron , naphthalene , isoquinoline , quinazoline , quinoxaline , ring (chemistry) , computational chemistry , stereochemistry , organic chemistry , molecule
A quantitative study on local aromaticity has been performed on a series of mono‐ and di‐substituted biheterocycles (quinoline, isoquinoline, quinoxaline, quinazoline). Three electronically based indices (PDI, ATI, and FLU) have been employed to investigate the substituent effect on the π ‐electron delocalization in both heterocycle and benzenoid rings. Three typical substituents (Cl, OCH 3 , and CN) with different inductive and resonance power have been selected. Generally, substituent causes a reduction in aromaticity irrespective of whether it is electron attracting or electron donating. It is shown that the maximum aromaticity exhibits a similar trend of Cl > CN > OCH 3 for all the studied rings. Moreover, it is found that the substituent situation with respect to the heteroatom has a significant influence on the aromaticity. It results from our study that in di‐substituted derivatives, irrespective of whether the two substituents form a meta or para isomer, they preferably choose the position which leads to the maximum aromaticity character. Copyright © 2009 John Wiley & Sons, Ltd.