Energetic metal-organic frameworks achieved from furazan and triazole ligands: synthesis, crystal structure, thermal stability and energetic performance

• Published in: New journal of chemistry Vol. 45; no. 47; pp. 22299 - 2235
• Main Authors: Gong, Lishan, Chen, Guo, Liu, Yue, Wang, Tingwei, Zhang, Jianguo, Yi, Xiaoyi, He, Piao
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 06.12.2021
• Subjects: Bomb calorimeters; Bomb calorimetry; Coordination compounds; Crystal structure; Detonation; Energetic materials; Flux density; Heat of combustion; Heat of formation; HMX; Hydrogen bonds; Infrared spectroscopy; Ligands; Mathematical analysis; Metal-organic frameworks; NMR spectroscopy; Single crystals; Structural stability; Synthesis; Thermal stability; Triazoles
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d1nj04486a

Energetic metal-organic frameworks (EMOFs) have witnessed increasing development and been proved as promising candidates for new high energy density materials (HEDMs). Here, three metal energetic complexes based on 3,4-diaminofurazan (DAF) and 3-amino-1 H -1,2,4-triazole (Hatz) ligands have been synthesized via a routine method and fully characterized by IR, 1 H NMR, 13 C NMR spectroscopy, X-ray single-crystal diffraction and DSC-TG techniques. The standard heats of combustion were obtained by an oxygen bomb calorimeter, and the detonation performance was calculated using the EXPLO5 program. Crystal structure determinations reveal that 1 shows a one-dimensional zigzag chain structure consisting of Zn( ii ) and bidentate DAF, ultimately producing a 2D MOF through extensive hydrogen bond interactions. The crystal densities of these complexes are up to 1.9 g cm −3 at 298 K. The thermal analyses from the DSC-TG test show that most of them have good thermal stability with the highest decomposition temperature of 241 °C. The as-synthesized compounds possess highly positive heats of formation with values for 2 and 3 of 2329.30 kJ mol −1 and 3261.57 kJ mol −1 , respectively, and high heats of detonation with value for 2 of 10231 kJ kg −1 , superior to that of HMX and RDX, which are most powerful organic explosives in use today. Expectedly, they exhibit excellent detonation performance, of which 2 has the best detonation velocity (9405 m s −1 ) and detonation pressure (46.64 GPa), and thus shows a great promise for potential applications as a high-energy density material. In addition, DFT calculations were performed in order to investigate the electronic properties based on the structures. This study highlights the great potential of nitrogen-rich group containing EMOFs (or complexes) for new eco-friendly energetic materials. Energetic metal-organic frameworks (EMOFs) have witnessed increasing development and been proved as promising candidates for new high energy density materials (HEDMs).