Synthesis of O- and N-substituted pentaiodobenzenes bearing σ-symmetric delocalized orbitals using site-selective nucleophilic aromatic substitution reactions

We report the synthesis of oxygen- and nitrogen-substituted (O- and N-substituted) pentaiodobenzenes using site-selective nucleophilic aromatic substitution (SNAr) reactions. Single-crystal X-ray diffraction analysis and theoretical calculations of thus synthesized pentaiodobenzenes reveal that their highest occupied molecular orbital (HOMOs) are composed of circularly delocalized sigma-symmetric orbitals, as found in hexa-substituted benzenes bearing heavy atoms such as selenium and iodine.