Molecular Diagrams of Some Nonbenzenoid Aromatic Hydrocarbons

Publisher Website
Google Scholar
Abstract
The charge densities, π‐bond orders, free valences, and vertical stabilization energies have been calculated by a semiempirical LCAO‐MO‐SCF method for pentalene, heptalene, fulvalene, sesquifulvalene, and heptafulvalene. The changes in the above quantities in going from the Hückel theory to the SCF method were found to be quite large for the fulvalenes. If one adopts the lack of chemical reactivity as a criterion for aromaticity then the results indicate that all five molecules and particularly the fulvalenes will have very little aromatic character.