Bisazapentalene Dication: Global Aromaticity and Open-Shell Singlet Ground State.

Antiaromatic moieties fused in polycyclic π-conjugated molecules usually exhibit strong localized antiaromaticiy. Herein, we reported the synthesis and properties of a bisazapentalene dication ( BAP 2+ ) obtained from in situ two-electron oxidation of neutral species 8 . Noteworthily, it possesses global aromaticity and an open-shell singlet ground state. This study underlines the importance of heteroatoms in determining the delocalization of π-electrons and the aromaticity of molecules in their oxidized states.