Theoretical Study of Hypervalent Bonds in 1,6-Diaza-1,6-dihydro- and 1,6-Dihydro-1,6-dioxapentalene Systems with a Heteroatom X at 6a Position (X=14-16 Group Atoms)

The present study theoretically investigated hypervalent bonding systems with the skeleton of pentalene. Geometries and energetics were examined by density functional theory calculations with triple-zeta class basis sets. The bond energies of the O-X and N-X hypervalent three-center four-electron bonds were estimated. Furthermore, the relationships between the bond-switching equilibration reactions and the stabilities of the hypervalent bonding intermediates were examined.