Energetic coordination polymers derived from 2,3,5,6-tetrakis(1H-tetrazol-5-yl)pyrazine: catalyzing the thermal decomposition of ammonium perchlorate.

Ammonium perchlorate (AP) is the dominant oxidizer in composite solid propellants, and its thermal decomposition critically determines the overall burning rate and energy-release behavior. To optimize this process, a nitrogen-rich energetic ligand 2,3,5,6-tetrakis(1H-tetrazol-5-yl)pyrazine (H4TTP) was employed to construct two novel energetic coordination polymers (ECPs), [Mn2(TTP)(H2O)4]n·2H2O (ECP-1) and [Zn2(TTP)(H2O)4]n (ECP-2). Structural characterization reveals that both ECPs feature robust one-dimensional chain architectures and good thermal stability. Thermal evaluations demonstrate exceptional catalytic performance, where the addition of 10% ECP-1 or ECP-2 shifts the high-temperature decomposition (HTD) of AP downward by 77.9 °C and 69.2 °C, respectively. Kinetic analyses confirm that ECP-1 dramatically reduces the apparent activation energy (Ea) of AP from 211.6 to 100.9 kJ mol-1, while ECP-2 yields a reduction of 47.7 kJ mol-1. Furthermore, mechanistic investigations via residue and TG-FTIR analyses elucidate the in situ transformation of ECP-1 into active Mn2O3 species, which induces surface cracking and accelerates the conversion of N2O and NOx intermediates. In addition, vacuum stability and hygrothermal evaluations establish that ECP-1 possesses excellent chemical compatibility with primary propellant ingredients and maintains consistent catalytic activity across extreme moisture conditions. These findings demonstrate that H4TTP-based coordination polymers are multifunctional catalysts for advanced solid propellant formulations.