Heterobimetallic Catalysts for the Thermal Decomposition of Ammonium Perchlorate: Efficient Burning Rate Catalysts for Solid Rocket Motors and Missiles

We show the synthesis and characterization of four heterobimetallic compounds derived from s-indacene of general formula [{(CO)(3)Mn}-s-Ic-{MCp*}](q) with M = Fe, Co, Ni, and Ru; q = 0, 1+. The complexes reported here were characterized by H-1 and C-13 NMR, elemental analysis and FT-IR. Additionally, the X-ray crystal structure of [(CO)(3)Mn-s-Ic-FeCp*] (1) and Mossbauer spectra are reported. The heterobimetallic compounds exhibit higher quasireversible redox potentials compared with ferrocene and catocene under the same reaction conditions. The complexes were tested as catalysts on the thermal decomposition of ammonium perchlorate examined by a differential scanning calorimetry technique to study their catalytic behavior. Compound (1) causes a decrease of ammonium perchlorate's decomposition temperature to 315 degrees C, consequently increasing the heat release by 138 J.g(-1). Conversely, [{(CO)(3)Mn}-s-Ic'-{CoCp*}] (2) presents a higher heat release (2462 J.g(-1)), comparable to catocene.

Automated summary

The synthesis and characterization of four heterobimetallic compounds derived from s-indacene were presented, showing higher quasireversible redox potentials compared with ferrocene and catocene. These compounds were tested as catalysts on the thermal decomposition of ammonium perchlorate, with compound (1) causing a decrease in decomposition temperature and an increase in heat release, while compound (2) exhibited a higher heat release comparable to catocene.