Separation of the Energetic and Geometric Contributions to Aromaticity. 3. Analysis of the Aromatic Character of Benzene Rings in Their Various Topological and Chemical Environments in the Substituted Benzene Derivatives

Molecular geometry of 2045 rings of all kinds of the substituted benzene derivatives enabled estimation of their index of aromaticity HOMA and its components GEO and EN (geometric and energetic contributions, respectively). It is shown that the benzene ring in substituted derivatives loses its aromatic character to a much smaller extent than in the case where it is embedded in benzenoid hydrocarbons. In all cases of substituted benzene derivatives dearomatization due to substitution is mostly due to the geometric term.