BN/BO-Ullazines and Bis-BO-Ullazines: Effect of BO Doping on Aromaticity and Optoelectronic Properties

We have achieved substitutional doping
of ullazine with either
two BO units or with one BO unit and one BN unit. The synthesis of
these B-doped ullazines is straightforward, using demethylation and
borylative cyclization as the key steps. Ullazine cores of both BN/BO-ullazines
(2) and bis-BO-ullazines (3) are very close
to being planar. Their electronic and photophysical properties were
investigated by ultraviolet–visible, fluorescence spectroscopy,
cyclic voltammetry, and density functional theory calculations.