Thermally stable and insensitive energetic metal-organic frameworks based on two new tetrazole ligands

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 (T_d) 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.