The theoretical study of aromaticity in N-heteroatom compounds

Abstract

In this article, we used nucleus-independent chemical shifts (NICS), aromatic stabilization energies (ASE), and magnetic susceptibility isotropic, calculated with (density functional theory) B3LYP levels at the 6-311+G (d, p) basis set, to evaluate the aromaticity of a set of 12 six-member planar p-electron aromatic systems: mono-and multi-substituted benzenes by nitrogen atoms. NICS were calculated at the center of the rings, 0.5 Å and 1 Å above the molecular plane, and in order to reflect the p-electron effects, we compare the values of NICS(0.5). The result statistically revealed significant correlations among the above three criteria. The comparison result was obtained as benzene > mono-nitrogen benzene > di-nitrogen benzene > tri-nitrogen benzene > tetra-nitrogen benzene > penta-nitrogen benzene.

On the basicity and π-electron delocalization of ‘hexaazabenzene’ N6 – Quantum-chemical studies

“…Mandado et al investigating various azines, concluded that aromaticity of azines decreases with the number of N atoms in the ring [23]. Similar order of aromaticity was reported by Dong et al [24] and Firme et al [25]. Divergent conclusions were derived by Sola et al [26].…”

Aromaticity in heterocyclic analogues of benzene: comprehensive analysis of structural aspects, electron delocalization and magnetic characteristics

“…However, calculations of aromaticity indices indicate that these simple rules fail in some cases. For example, the degree of aromaticity in some nitrogen-containing rings 42 and a wide range of five-membered species 43 is almost the same as benzene or even higher.…”

A DFT Study on the Stability and Aromaticity of Heterobenzenes Containing Group 15 Elements

“…The present paper deals with the evaluation of aromaticity of mono-, di-, tri, tetra-, penta-, and hexasubstituted heterobenzenes with N, P, and As atoms (see Fig. Literature survey reports experimental and theoretical studies regarding the heteroanalogues of benzene where one or more CH units are replaced by isovalent species [8][9][10][11][12]. Literature survey reports experimental and theoretical studies regarding the heteroanalogues of benzene where one or more CH units are replaced by isovalent species [8][9][10][11][12].…”

“…1). Literature survey reports experimental and theoretical studies regarding the heteroanalogues of benzene where one or more CH units are replaced by isovalent species [8][9][10][11][12]. Figure 1 presents the heterobenzenes series that were investigated within the present paper.…”