Aromaticity as a Quantitative Concept. 3. Benzo‐fused five‐ and six‐membered heterocycles

Abstract

A rather complete data set for 12 characteristics of 18 common benzo‐fused heterocycles yields two significant principal components. The loadings of the characteristics show a close correlation with those found for the same characteristics of monocyclic heterocycles. The scores for each bicycle are also closely related to those for the corresponding monocycle. The method demonstrates considerable predictive power.

Edge modification of PAHs: the effect of embedded heterocycles on the aromaticity pattern

“…Although the concept of aromaticity is well-known, its description and quantification is still difficult. There are multiple approaches to describe this phenomenon, the most commonly used methods are using either geometry-based, energetic, electronic or magnetic descriptors [3,[28][29][30][31][32][33][34]. Each of these methods have their limitation, but in general cases they show significant collinearity [35].…”

Aromaticity as a Quantitative Concept. 6. Aromaticity Variation with Molecular Environment

“…In particular, geometrical criteria, and notably the Pozharskii and Bird aromaticity indices, were essentially “classical”, whereas magnetic criteria defined “magnetic” aromaticity. Subsequent papers refined the treatment for 16 familiar five- and six-membered monocyclic heterocycles and extended it to benzo-fused derivatives, and to less familiar monocycles . We applied semiempirical methods to calculate aromaticity indices and have summarized this work …”

QSPR Modelling of Lanthanide‐Organic Complex Stability Constants

“…Examples of some of applications of PC analysis in heterocyclic chemistry include investigations of (i) aromaticity 32,33,34,35 and of (ii) simultaneous dependence of S N 2 rates on alkyl group structure and leaving group nucleofugacity in nucleophilic displacements in which heterocycles act as leaving groups 36,37 . A multivariate statistical treatment was used for solvent characteristics where large numbers of solvents and many scales new dimensions to the problems generally investigated in LFERs.…”