Thermally stable and insensitive energetic metal-organic frameworks based on two new tetrazole ligands
Lü Li, Sitong Chen, Siwei Song, Qinghua Zhang
Abstract
Two new tetrazole ligands were designed and synthesized using simple methods in this study, namely 1H-tetrazole-5-carbohydrazide (HCHT, 1) and 2-amino-5-(1H-tetrazol-5-yl)-1,3,4-oxadiazole (HAOT, 2). Their solvent-free potassium salts [K(CHT)]n (3) and [K(AOT)]n (4) are new two-dimensional energetic metal-organic frameworks (EMOFs), and their structures were characterized using nuclear magnetic resonance (NMR), infrared spectroscopy (IR), mass spectrometry (MS), elemental analysis (EA), and single-crystal X-ray diffraction (SXRD). Both compounds 3 and 4 exhibit high decomposition temperatures (Td) of 314 °C and 310 °C, respectively and are highly insensitive to impact and friction stimuli (IS > 40 J, FS > 360 N). The detonation velocity and pressure of 3 were calculated at 9141 m s−1 and 29.0 GPa, respectively, and those of 4 were determined at 8423 m s−1 and 24.5 GPa, respectively. Furthermore, intermolecular interactions in 3 and 4 were analyzed using 2D fingerprint plots with associated Hirshfeld surfaces. In this manner, two thermally stable and insensitive EMOFs were developed based on two new tetrazole ligands.