Synthesis of a π-Extended Phenazine Diimide Derivative and Characterization of Its Closed-Shell Reduced States

In this work, a systematic synthesis of π-extended phenazine diimide derivatives is reported along with an extensive characterization of the optoelectronic properties of these molecules. The synthetic approach, based on the functionalization of naphthalene imide derivatives, enables both the direct synthesis of phenazine diimides and the preparation of phenazine dianhydride, thus resulting in a great synthetic versatility. Also, a comprehensive computational and spectroscopic characterization of the closed-shell reduced forms of phenazine diimides was carried out. The results indicate the differential formation of a dihydrophenazine or of an uncommon Meisenheimer complex, depending on the reduction conditions. These results highlight the great importance of structural design and reaction conditions in determining the nature of the reduced form of organic molecules, with important implications for the applications of these species as reagents and catalysts.