Molecular Vibrational Constants and Chemical Bonding in Five-Membered Heteratomic Compounds

By means of the force field and mean amplitudes of vibration of furan, thiophene, selenophene and tellurophene molecules, we have concluded that the ground-state aromaticity order in the series is thiophene > tellurophene > selenophene > furan. The reactiv i ty of these molecules to the electrophilic substitution follows the order furan > selenophene ∼ tellurophene > thiophene.