Adjusting the Coordination\nConfiguration by Changing\nElectrostatic Potential: Introducing N/O/S Heteroatoms Based on the\nElectronic Effect

Energetic coordination compounds (ECCs) have demonstrated\nunique\nadvantages in regulating the physicochemical properties of energetic\nmaterials through the design of organic ligands. The fundamental approach\ninvolves altering the electron cloud density distribution of organic\nligands to modify the characteristics of coordination sites and, thus,\nachieve new coordination configurations. In this study, Mulliken charge\ndistribution and surface electrostatic potential analysis were used\nto elucidate the effects of pyridinic N, pyrrolic N, oxazolic O, and\nthiazolic S on the electron cloud density of carbohydrazide groups\nthrough the induction effect and conjugate effect. Furthermore, three\nAgClO<sub>4</sub>-based ECCs were synthesized based on 1<i>H</i>-imidazole-4-carbohydrazide, oxazole-4-carbohydrazide, and thiazole-4-carbohydrazide.\nSingle-crystal X-ray diffraction analysis revealed that [Ag(IZ-4-CA)ClO<sub>4</sub>]<i><sub>n</sub></i> has a one-dimensional (1D)\nchain structure, while Ag<sub>2</sub>(OZCA)<sub>2</sub>(ClO<sub>4</sub>)<sub>2</sub> and Ag<sub>2</sub>(SZCA)<sub>2</sub>(ClO<sub>4</sub>)<sub>2</sub> exhibit zero-dimensional structures. The 1D structure,\nwith good planarity, results in [Ag(IZ-4-CA)ClO<sub>4</sub>]<i><sub>n</sub></i> having lower mechanical sensitivity (IS = 21\nJ, FS = 80 N). The introduction of oxazolic O enhances oxygen balance\n(OB), leading to a higher predicted detonation velocity and pressure\nfor Ag<sub>2</sub>(OZCA)<sub>2</sub>(ClO<sub>4</sub>)<sub>2</sub> (<i>D</i> = 6.4 km s<sup>–1</sup>, <i>P</i> = 23.6\nGPa). Although the introduction of thiazolic S is unfavorable for\nimproving oxygen balance, Ag<sub>2</sub>(SZCA)<sub>2</sub>(ClO<sub>4</sub>)<sub>2</sub> exhibits the highest initial decomposition temperature\namong the three, at 232 °C. Additionally, initiation tests demonstrated\nthat three ECCs can successfully detonate cyclotrimethylenetrinitramine\n(RDX), indicating good initiation capabilities.