Novel 3D cesium(I) based EMOF of nitrogen-rich triazole derivatives as a “green” orange-light pyrotechnics
In this paper, an ingenious strategy based on constructing energetic metal-organic frameworks (EMOFs) with cesium salts for new green and practical pyrotechnic composition has been described. In order to obtain non-hygroscopic, chlorine-free formulation, a novel triazole nitrogen-rich energetic ligand N-(5'-amino-1H,1'H-[3,3'-bi(1,2,4-triazol)]-5-yl)nitramine (HABTNA) was designed and synthesized, which exhibited some good properties, such as insensitivity, high nitrogen content and energy and excellent oxygen balance. More importantly, using this triazole ligand and cesium(I) salts an energetic metal-organic framework (EMOF) structure pyrotechnic colorant was built through simple and green aqueous solution crystallization method. The results of single crystal X-ray diffraction experiments shown that this EMOF has a compact three-dimensional structure with high density. Physical and chemical properties tests revealed that this Cs(I) based MOF have excellent moisture resistance and thermal stability, at the same time, it was also proved as a high-energy insensitive energetic material with energy level up to the explosive level. Through systematic pyrotechnics performance experiment, a chlorine-free pyrotechnics formulation with this flammable EMOF as the main component was developed, which was the first orange-light-emitting pyrotechnic formulation with high color purity and intensity.