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

A detailed study of the geometry, aromatic character, electronic and magnetic properties for a series of positively charged N-doped 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.

Automated summary

A detailed study on the geometry, aromatic character, electronic and magnetic properties of positively charged N-doped polycyclic aromatic hydrocarbons (PAHs) was conducted. Magnetic properties were analyzed using the magnetically induced current density method. Comparative studies on local aromaticity were performed using different indices. The presence of N-atoms caused planarity distortion in the studied N-doped systems. Geometric changes and charged nature did not significantly affect current density and local aromaticity compared to parent benzenoid hydrocarbons. This study demonstrates the use of quantum chemical calculations in the design and fine tuning of PAH properties.