Improved Detonation Performance Via Coordination Substitution: Synthesis and Characterization of Two New Green Energetic Coordination Polymers

In this work, a new energetic coordination polymer (ECP), [Cu(HBTI)(H2O)]n (1) (H3BTI = 4,5-bistetrazole-imidazole), was synthesized by a hydrothermal method. Due to the existence of coordination water molecules in 1, however, its energy density was limited, which led to the insufficient detonation performance. To further improve its detonation performance, [Cu(H2BTI)(NO3)]n (2) was then obtained by substituting the coordinated water molecule in 1 with nitrate through the coordination substitution reaction under acidic conditions. The structures of two ECPs were respectively characterized using X-ray single-crystal diffraction, and the theoretical density of 2 (2.227 g·cm-3) was greater than 1 (1.851 g·cm-3). Thermogravimetric analyses showed that 2 has a one-step rapid weight loss process compared with the two-step slow weight loss process of 1. The theoretical calculations indicated that the detonation performances of 2 were better than those of 1. Moreover, the promotion effects of two ECPs on the combustion decomposition of ammonium perchlorate were studied using a differential scanning calorimetry method.