Tuning the Structure and Properties of N‐doped Positively Charged Polycyclic Aromatic Hydrocarbons

Abstract

This work is dedicated to the seminal contributions of Professor Klaus Müllen and Professor Ivan Gutman to science and on the occasion of their 75th birthday.A detailed study of the geometry, aromatic character, electronic and magnetic properties for a series of positively charged Ndoped polycyclic aromatic hydrocarbons (PAHs) was performed. Magnetic properties of the examined molecules were analyzed by means of the magnetically induced current density calculated using the diamagnetic-zero version of the continuous transformation of origin of current density (CTOCD-DZ) method. The comparative study of the local aromaticity of the studied molecules was performed using several different indices: energy effect (ef), harmonic oscillator model of aromaticity (HOMA) index, six centre delocalization index (SCI) and nucleus independent chemical shifts (NICS). The presence of N-atoms in the inner rings was found to cause a planarity distortion in the studied N-doped systems. The geometric changes and charged nature of the studied N-doped systems do not significantly influence the current density and the local aromaticity distribution in comparison with the corresponding parent benzenoid hydrocarbons. The present study demonstrates how quantum chemical calculations can be used for rational design of novel PAHs and for fine tuning of their properties.

Computational Studies on the Structures of Nanographenes with Various Edge Functionalities

“…Various computational studies on NGs and related carbons, such as graphene nanoribbons with or without heteroatom dopants, have been reported [19–29] . These studies have often focused on hydrogen‐terminated NGs, and in some cases, these NGs have zigzag edges.…”

“…Various computational studies on NGs and related carbons, such as graphene nanoribbons with or without heteroatom dopants, have been reported. [19][20][21][22][23][24][25][26][27][28][29] These studies have often focused on hydrogen-terminated NGs, and in some cases, these NGs have zigzag edges. However, the edge structures of experimentally obtainable NGs, such as those produced by an acid-assisted oxidative cleavage of graphite [13] and finely crushed graphite, [30] obtained by the so-called top-down method, are dominated by carboxy group terminated armchair edges (Figure 1).…”