Rational Design of High-Performance Energetic Coordination Compounds via Nitrate Anion Integration.

A major challenge in energetic materials research is the development of compounds that simultaneously exhibit high density, high heats of detonation, excellent detonation performance, and acceptable safety characteristics through efficient incorporation of energetic functionalities into compact frameworks. In this regard, reaction conditions play a critical role in governing the self-assembly of energetic ligands with metal ions and thereby influencing the architecture and properties. Herein, two nitrate-containing energetic coordination compounds, [Ni3(TATa)6(H2O)6]·6NO3(Ni-ECC) and [Cu(TATa)2(NO3)3]·NO3(Cu-ECC), were synthesized and characterized by infrared spectroscopy, TGA-DSC, elemental analysis, PXRD, and single-crystal X-ray diffraction. Evaluation of their properties revealed detonation velocities of 7222 and 8634 m s-1, respectively. Notably, Cu-ECC possesses a solvent-free three-dimensional dense supramolecular framework with a crystal density of 2.04 g cm-3 and reduced impact and friction sensitivities of 20 J and 360 N. Its detonation performance (VOD = 8634 m s-1; DP = 36.4 GPa) approaches that of RDX, placing it among the promising ECCs reported to date. Hirshfeld surface and fingerprint analyses indicate that noncovalent interactions stabilize nitrate ions and reinforce structural integrity. Furthermore, Cu-ECC produced a 3.4 cm dent in a 5 mm lead plate in a detonation test, demonstrating potential as a secondary explosive.