Energetic Metal-Organic Frameworks Incorporating NH3OH+ for New High-Energy-Density Materials.

Abstract

Energetic metal-organic frameworks (E-MOFs) have witnessed increasing development over the past several years. However, as a highly energetic cation, NH3OH+ has never been explored to construct transition-metal-based E-MOFs. Herein, we report the first examples of NH3OH+-containing E-MOFs with bis(tetrazole)methane (H2btm) as a ligand and copper and manganese as central metal ions, [(NH3OH)2(Cu(btm)2)]n and [(NH3OH)2(Mn(btm)2)]n. Crystal structure determinations reveal that both E-MOFs show two-dimensional layered structures. Experimental results suggest that they have high thermal decomposition temperatures (>200 °C). Among them, Cu-based E-MOFs possesses outstanding thermal stability (Tdec = 230.3 °C), which surpasses those of known NH3OH+-containing compounds. They also have high energy density; in particular, the Cu-based E-MOF affords a high heat of combustion (11447 kJ kg-1) and high heat of detonation (713.8 kJ mol-1) beyond the most powerful organic explosives in use today. Additionally, the two E-MOFs show completely different sensitivity properties: the Mn-based E-MOF is an insensitive high-energy-density material (IS > 40 J; FS > 360 N; EDS > 20 J), while the Cu-based E-MOF can be classified as a sensitive energetic material (IS = 13 J; FS = 216 N; EDS = 10.25 J), demonstrating their diverse applications in different fields. Our research proposes a unique class of high-energy-density materials.