Coordination polymerization of nitrogen-rich linkers and dicyanamide anions toward energetic coordination polymers with low sensitivities

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 52; no. 3; pp. 818 - 824
• Main Authors: Xie, Hao-Hui, Wang, Qin, Weng, Jiao-Lin, Yan, Yun-Fan, Bian, Hong-Yi, Huang, Ying, Zheng, Fa-Kun, Qiu, Ren-Hui, Xu, Jian-Gang
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 17.01.2023
• Subjects: Anions; Coordination polymers; Detonation; Energetic materials; Ligands; Nitrogen; Oxidizing agents; Polymerization; Sensitivity; Tetrazoles
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d2dt03180a

The design and synthesis of energetic materials (EMs) with high energy and reliable stabilities has attracted much attention in the field of EMs. In this work, we employed a strategy of the coordination polymerization of mild dicyanamide ions (DCA ), two isomeric ligands 1-methyl-5-aminotetrazole (1-MAT) and 2-methyl-5-aminotetrazole (2-MAT) to construct energetic coordination polymers (ECPs). Four new ECPs {[Co(DCA) 2 (1-MAT) 2 ]·H 2 O} n 1 , [Cu(DCA) 2 (1-MAT)] n 2 , [Cd(DCA) 2 (1-MAT) 2 ] n 3 and [Cd(DCA) 2 (2-MAT) 2 ] n 4 were successfully synthesized through solvent evaporation routes. Compounds 1 and 4 display 1D chains, while 2 and 3 exhibit 2D-layered structures. Compounds 1-3 with the 1-MAT ligand all exhibit reliable thermal stabilities (> 200 °C). The calculated heats of detonation (Δ H det ) of 1-3 are all higher than 1.4 kJ g −1 , which are higher than traditional explosive TNT (1.22 kJ g −1 ) and the reported ECP AgMtta (HMtta = 5-methyl-1 H -tetrazole, Δ H det = 1.32 kJ g −1 ). Furthermore, sensitivity testing demonstrates that 1-4 features low mechanical sensitivity to external mechanical action in contrast with the extremely sensitive azide-based ECPs [Cu 3 (2-MAT) 2 (N 3 ) 6 ] n . In addition, compound 2 shows hypergolic properties via an 'oxidizer-fuel' drop experiment, demonstrating its application prospects in the field of propellants. This work details an approach of synthesizing multipurpose ECPs with reliable stabilities by introducing mild dicyanamide anions into nitrogen-rich skeletons. Dicyanamide anions are introduced into nitrogen-rich skeletons to construct multipurpose ECPs with high energy, low sensitivities, and hypergolic properties.