The Radical Anion and Dianion of Benzo[3,4]cyclobuta[1,2-b]phenazine

We present the reduction of two azaacenes (a benzo[3,4]cyclobuta[1,2-b]phenazine and a benzo[3,4]cyclobuta[1,2-b]-naphtho[2,3-i]phenazine derivative), featuring a single cyclobutadiene unit, to their radical anions and dianions. The reduced species were produced using potassium naphthalenide in the presence of 18-crown 6 in THF. Crystal structures of the reduced representatives were obtained and their optoelectronic properties evaluated. Charging these 4n Hu''ckel systems gives dianionic 4n + 2 pi-electron systems with increased antiaromaticity, according to NICS(1.7)zz calculations, featuring unusually red-shifted absorption spectra.

Automated summary

This study presents the reduction of two azaacenes to their radical anions and dianions, leading to increased antiaromaticity and red-shifted absorption spectra. Crystal structures of the reduced species were obtained and their optoelectronic properties were evaluated. The reduction was achieved using potassium naphthalenide in the presence of 18-crown-6 in THF.