Synthesis and properties of 1-methylimidazole-nitrocyanamide energetic complex

An energetic complex, [Cu(MIM) 4 ](NCA) 2 (NCA = nitrocyanamide anion, MIM = 1-methylimidazole), was synthesized and characterized by Fourier transform infrared spectroscopy, single-crystal diffraction, powder X-ray diffraction, differential scanning calorimetry (DSC), and thermogravimetry. The DSC curve of [Cu(MIM) 4 ](NCA) 2 was recorded in the temperature range of 40–500 °C, featuring an endothermic melting peak at 93.5 °C and exothermic decomposition peak at 199.4 °C. This complex spontaneously ignited upon contact with white fumed nitric acid (ignition delay time = 16 ms), yet exhibited friction and impact sensitivities (240 N and > 40 J, respectively) sufficiently high for safe handling. [Cu(MIM) 4 ](NCA) 2 was a better catalyst for the thermal decomposition of ammonium perchlorate (AP) than [Cu(MIM) 4 ](DCA) 2 (DCA = dicyanamide anion) and [Cu(MIM) 4 ](CBH) 2 (CBH = cyanoborohydride anion), featuring a lower peak temperature (285.6 °C) and activation energy of AP decomposition (81.5 kJ·mol −1 ) while exhibiting a higher heat release (2458 J·g −1 ). Thus, [Cu(MIM) 4 ](NCA) 2 was found to be a promising catalyst for composite propellant decomposition.