ON ABSOLUTE AROMATICITY WITHIN ELECTRONEGATIVITY AND CHEMICAL HARDNESS REACTIVITY PICTURES

The absolute aromaticity formulation based on the comparison between the pre-bonding stage of atoms-in-molecules and the post-bonding stage of molecular orbitals is advanced. The specialized electronegativity and chemical hardness- based absolute aromaticity indices are proposed within various computational schemes of compact finite differences of frontier orbitals up to the spectral-like resolution, with the scales trends established through their popular reactivity principles, respectively. The reliability of the obtained aromaticity scales was tested throughout the consecrated geometrical, topological, energetic (including thermodynamic), and magnetic criteria on a paradigmatic set of benzenoid hydrocarbons. The Mulliken electronegativity-based aromaticity scale was found to correlate best with exaltation of magnetic susceptibility, whereas for the chemical hardness the fashioned HOMO-LUMO gap description of aromaticity was improved towards its second and third order differences that prove superior agreement with aromaticity scales based on topologic analysis. The best correlations found in modeling the aromaticity criteria by the chemical hardness-based schemes of computations advocate considering further the associate hardMATCH