Innovative Concept of Designing Primary Explosives by IntroducingPolymers: Preparation and Investigation of {[Ca(CHZ)₂](ClO₄)₂}_n(CHZ = carbohydrazide)

A novel alkaline-earth metal perchlorate coordination polymer {[Ca(CHZ)₂](ClO₄)₂}_n(1, CHZ = carbohydrazide) was synthesized and characterized. The X-ray single-crystal diffraction results illustrate that the structure of the complex belongs to a tetragonal system, space group I-42m. Every Ca²⁺ion is octa-coordinated with four CHZ groups. The CHZ group forms a tridentate coordination mode with different Ca²⁺ions, leading to a coordination polymer structure. Therefore, the molecule is extended to a super 1D infinite polymer, and the configuration of the Ca²⁺ion is a distorted dodecahedron. The DSC results show only one exothermal decomposition process with a peak temperature of 242.2 °C. The TG-DTG curves demonstrate a 58 % mass loss from 210–290 °C and that finally 18 % of the polymer remains. Experimental data show that the combustion heat is –6.41 MJ kg^–1and the enthalpy of formation is –610.9 kJ mol^–1. Non-isothermal kinetic and thermodynamic parameters are obtained from Kissinger's method as well as Ozawa's method. The critical temperature of thermal explosion, ΔS^≠, ΔH^≠, and ΔG^≠are calculated as 234.7 °C, 134.1 J K^–1mol^–1, 213.8 kJ mol^–1, and 147.0 kJ mol^–1, respectively. Additionally, the sensitivities towards impact and friction are assessed to be 0.5 J and 28 N from the relevant standard methods.