Double aromaticity arising from σ- and π-rings

• DOI: 10.1038/s42004-018-0057-4
• Publication Date: 2018-09-21T12:09:51Z
• Authors: Shunsuke Furukawa; Masahiro Fujita; Yoshihiko Kanatomi; Mao Minoura; Miho Hatanaka; Keiji Morokuma; Kazuya Ishimura; Masaichi Saito
• Keywords: Dication; Antiaromaticity

Abstract Aromaticity has been a central concept in chemistry since the discovery of benzene 19th century and impacted science delocalized π-electron systems. The aromaticity conventional aromatic compounds usually originates from electron delocalization through single ring that consists π-symmetric orbitals. Although double aromaticity, i.e. composed two circularly orbitals, theoretically predicted for over 20 years, bench-stable compound is not well explored by experiment. Here we report synthesis isolation dication hexakis(phenylselenyl)benzene, as its based on structural, energetic, magnetic criteria. In this dication, cyclic σ-symmetric orbitals are formally occupied ten six electrons, respectively, thus follows 4 n + 2 ( = 1, 2,…) Hückel rule, regardless σ-orbital or π-orbital symmetry.