Flash Communication: Effects of Extension of Lone-Pair Interactions via σ-Symmetric Orbitals through Nonbonded Atoms

Abstract

To investigate the effects of extension of lone-pair interactions via σ-symmetric orbitals through nonbonded atoms, we prepared perselenated naphthalenes, -pyrenes and -anthracenes. In contrast to the π-delocalized systems, the HOMOs of these molecules are characterized by antibonding interactions between lone-pair electrons on the selenium atoms, resulting in the σ-symmetric orbital interactions along the periphery of the aromatic hydrocarbon platforms (denoted as σ-delocalization in this work). Consequently, the molecules deviate from planarity to reduce the HOMO energy levels. Under these conditions, increasing the number of selenium atoms leads to a rise in the HOMO energy levels.