Nitrogen-Rich Tetranuclear Metal Complex as a New Structural Motif for Energetic Materials

For designing energetic materials (EMs), the most challenging issue is to achieve a balance between energetic performance and reliable stability. In this work, we employed an efficient and convenient method to synthesize a new class of EMs: nitrogen-rich tetranuclear metal complexes [M­(Hdtim)­(H₂O)₂]₄ (M = Zn <b>1</b>, Mn <b>2</b>; H₃dtim = 1<i>H</i>-imidazol-4,5-tetrazole) with the N content of >46%. The structural analyses illustrate that isomorphous compounds <b>1</b> and <b>2</b> feature isolated hollow ellipsoid tetranuclear units, which are linked by both π–π interactions and hydrogen-bonding interactions to give a 3D supramolecular architecture. Compounds <b>1</b> and <b>2</b> exhibit prominent energetic characteristics: excellent detonation performances and reliable thermal, impact, and friction stabilities. Being nitrogen-rich tetrazolate compounds, the enthalpies of combustion of <b>1</b> (−11.570 kJ g^–1) and <b>2</b> (−12.186 kJ g^–1) are higher than those of classical EMs, RDX and HMX, and they possess high positive heats of formation. Sensitivity tests demonstrate that <b>1</b> and <b>2</b> are insensitive to external mechanical action. Excellent energetic performances and low sensitivities promote <b>1</b> and <b>2</b> to serve as a new class of promising EMs with a desirable level of safety