Synthesis and Structural Elucidation of Bisdibenzocorannulene in Multiple Redox States

Abstract

π‐Extended curved polycyclic hydrocarbons have attracted widespread attention in not only chemistry but also materials science. We now report an anti ‐folded bowl‐shaped bisdibenzocorannulene ( BDBC ), featuring a new chair‐cyclohexane‐like hexagon as a bridge of two dibenzocorannulene moieties. The neutral compound showed a multiple redox active property, and would be converted to the corresponding redox states through chemical reduction or oxidation. Chemical reduction of BDBC by stoichiometric addition of metallic potassium in the presence of [18]crown‐6 ether, provided a radical anion BDBC •− and a dianion BDBC 2− , respectively; while chemical oxidation by silver hexafluoroantimonate (V), invariably converted neutral compound to an open‐shell singlet diradical dication (BDBC •• ) 2+ . Our results revealed that structural consequence of both electron‐reduction and oxidation, were closely related to release of ring‐strain of bowl‐shaped π‐scaffold and imposed steric hindrance of the hexagonal bridge. In addition, the unusual open‐shell nature of the dication could mainly be attributed to the changing of localized antiaromaticity in closed‐shell structure to delocalized character in biradical, and thus emerging of weakly bonded π‐electrons.