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

J Org Chem. 2023 Mar 3;88(5):2742-2749. doi: 10.1021/acs.joc.2c02279. Epub 2023 Feb 21.

Abstract

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 Hückel systems gives dianionic 4n + 2 π-electron systems with increased antiaromaticity, according to NICS(1.7)zz calculations, featuring unusually red-shifted absorption spectra.