Energetic transition metal complexes based on 1-allylimidazole and nitrocyanamide: Syntheses, characterizations and catalytic performances on the thermal decomposition of ammonium perchlorate

To explore combustion catalysts for solid propellants, four novel energetic coordination compounds were prepared with the anion of nitrocyanamide (NCA) as the ligand and 1-allyl-imidazole (AIM) as the ligand, and transition metals Mn, Co, Ni, and Cu as the central ions. The structures of these compounds were [Mn(AIM)₄] (NCA)₂ (1), [Co(AIM)₄](NCA)₂ (2), [Ni(AIM)₄](NCA)₂ (3), [Cu(AIM)₄](NCA)₂ (4). The results showed that all of the compounds possessed high energy density, and compound 2 had a mass energy density (E_g) of 17.9 kJ g⁻¹ and a volume energy density (E_v) of 25.59 kJ cm⁻³. The catalytic effect of these compounds on the thermal decomposition of ammonium perchlorate (AP) was studied using DSC. The addition of 5 % catalyst to AP samples advanced the high-temperature decomposition temperature and significantly increased the heat release. Compound 4 exhibited the best catalytic performance, with an increased heat release of 1739 J g⁻¹, decomposition temperature advanced by 88.2 °C, and activation energy reduced to 74.74 kJ mol⁻¹. These results demonstrate the potential of these compounds as combustion catalysts for solid propellants.