Nitroaminofurazans with Azo and Azoxy Linkages: A Comparative Study of Structural, Electronic, Physicochemical, and Energetic Properties

The structural, electronic, and physicochemical properties of 4,4′-bis(nitramino)azofurazan and 4,4′-bis(nitramino)azoxyfurazan as high-energy density materials were compared. In addition, a new family of nitrogen-rich energetic salts based on these two nitroaminofurazans were synthesized and fully characterized. On the basis of experimental evidence and theoretical calculations, 4,4′-bis(nitramino)azoxyfurazan and its ionic derivatives were found to exhibit higher detonation velocities and pressures, and higher densities than their azofurazan analogues which supports the added value of introduction of the N-oxide moiety into energetic materials. The solid state features for the two nitroaminofurazans were studied in detail by X-ray diffraction and noncovalent interaction index which identify additional hydrogen-bonding and extensive edge-to-face π–π stacking interactions arising from the presence of the azoxy N-oxide.