Theoretical design and prediction of properties for dinitromethyl, fluorodinitromethyl, and (difluoroamino)dinitromethyl derivatives of triazole and tetrazole.

Abstract

Fluorine- and oxygen-rich compounds are promising as energetic materials for composite propellants, explosives, and pyrotechnics. As an effective and timesaving tool for screening the structures of potential energetic compounds, computer simulation has been widely used to predict the detonation or physicochemical properties of energetic molecules with relatively high precision. In this study, twelve series of dinitromethyl, fluorodinitromethyl, and (difluoroamino)dinitromethyl derivatives of triazole and tetrazole were designed by C- or N-functionalization. Their properties, including density, heat of formation, and detonation properties, were evaluated extensively using volume-based thermodynamic calculations and density functional theory. Among the investigated compounds, 1-(fluorodinitromethyl)-3-nitro-1,2,4-triazole (B3), 1-(fluorodinitromethyl)-4-nitro-1,2,3-triazole (F3), 4,5-bis(fluorodinitromethyl)-1,2,3-triazole (H3), and 5-(fluorodinitromethyl)-tetrazole (I3) displayed excellent integrated performance, that is, high density (≥1.95 g cm−3), oxygen balance (≥2.97%), detonation velocity (>8900 m s−1), and detonation pressure (>40.0 GPa). These results are expected to facilitate the synthesis of a new generation of fluorine- and oxygen-rich energetic compounds. More importantly, our design strategy of constructing nitrogen-rich molecular skeletons with highly dense substituents and highly positive heats of formation by C- or N-functionalization is a valuable approach for developing novel high-energy-density materials with excellent performance.