Functionalized planar aromatic rings as precursors to energetic N,N′-(4,6-dinitro-1,3-phenylene)dinitramide and its salts

Abstract

Functionalization of planar aromatic rings is very straightforward, up scalable, and economical in comparison with many azole, caged, linear or cyclic structures. In our present work, a facile synthesis of N,N′-(4,6-dinitro-1,3-phenylene)dinitramide (3) is obtained by a single-step nitration of 4,6-dinitrobenzene-1,3-diamine (2). Compound 3 exhibits a surprisingly high density of 1.90 g cm⁻³ at 100 K (1.87 g cm⁻³ at 298 K). Its reactions with bases result in the formation of a series of energetic salts (4–7) which exhibit relatively high densities (1.74 to 1.83 g cm⁻³), and acceptable thermal sensitivities (177 to 253 °C). Energetic salt formation increases intermolecular hydrogen bonding while the planarity of the aromatic ring maximizes weak non-covalent interactions (π-stacking, cation/π, anion-π, X-H/π, etc.,). The synergetic effect of these stabilizing interactions plays a crucial role in increasing thermal stability and decreasing sensitivity toward the external stimuli. Overall, these easily accessible new energetic compounds exhibit high densities and good denotation properties with potential applications as new high-energy materials.