Design and Synthesis of Energetic Materials towards Versatile Applications by N-trinitromethyl and N-nitromethyl Functionalization of Nitroimidazoles

Modifying the properties of energetic materials is important not only for gaining insight into the relationship between structures and properties but also for multiple applications. A new family of energetic compounds, polynitroimidazoles featuring trinitromethyl, nitromethyl and methyl acetate moieties at the nitrogen position of heterocyclic rings were synthesized. The high-energy oxidizers 2-nitro and 4-nitro-1-(trinitromethyl)-1H-imidazoles were obtained by nitration of 1-acetonylpolynitroimidazoles in fuming HNO 3 and concentrated H 2 SO 4 . 4,5-Dinitro-1-(nitromethyl)-1H-imidazole and 4,5-dinitro-1-(acetate methyl)-1H-imidazole were afforded by using 68 % HNO 3 and concentrated H 2 SO 4 through controllable synthesis. All the intermediates and the target compounds were confirmed by X-ray diffraction. It is noteworthy that one of the N-trinitromethyl nitroimidazole derivatives showed high density ( ρ : 1.88 g cm −3 ), attractive positive oxygen balance ( Ω : +18.3 %) and good detonation performance ( D : 9003 m s −1 ) exceeding those of ADN, while N-nitromethyl derivative behaved higher thermal stability and lower sensitivity in contrast to those of NG. N-acetate methyl derivative gave an interesting melt-castable property ( T m.p .: 86 o C, T d : 224 o C), acceptable detonation performance as well as low sensitivity towards impact and friction ( IS >40 J, FS >360 N), making it a competitive replacement for DNAN. These chemical and physical properties indicate that these novel materials show promising energetic performance towards future applications. Graphical A new family of neutral energetic derivatives based on polynitroimidazole backbones have been synthesized and fully characterized (see Figure). It is noteworthy that one of the N-trinitromethyl nitroimidazole derivatives showed high density (1.88 g cm -3 ), attractive positive oxygen balance (+18.3 %) and good detonation velocity (9003 m s −1 ) exceeding those of ADN, while N-nitromethyl derivative behaved higher thermal stability and lower sensitivity in contrast to those of NG. N-acetate methyl derivative gave an interesting melt-castable property, acceptable detonation performance as well as low sensitivity towards impact and friction, making it a competitive replacement for DNAN.