Nitrogen‐Rich Ligands Directed Transition Metal (Co/Ni/Zn) 3,5‐Dinitrobenzoic Acid Energetic Complexes: Syntheses, Crystal Structures and Properties

Abstract

AbstractEnergetic transition metal (Co/Ni/Zn) complexes based on 3,5‐dinitrobenzoic acid (DNBA), 1,5‐diaminotetrazole (DAT), and semicarbazide (SCZ) were synthesized and characterized by elemental analysis and IR spectroscopy. The structures of the nine complexes were confirmed by single‐crystal X‐ray diffraction as: [Co(DNBA)2(H2O)4⋅4(H2O)] (1), [Ni(DNBA)2(H2O)4⋅4(H2O)] (2), [Zn(DNBA)2]n (3), Co(SCZ)2(DNBA)2 (4), Ni(SCZ)2(DNBA)2 (5), Zn(SCZ)2(DNBA)2 (6), Co(DAT)2(DNBA)2(H2O)2 (7), Ni(DAT)2(DNBA)2(H2O)2 (8), Zn(DAT)2(DNBA)2(H2O)2 (9). It is worth mentioning that 3 exhibits a fascinating trigonal helical chain architecture bridged along the c‐axis by Zn(II) and carboxylic O atoms. Differential scanning calorimetry (DSC) and thermogravimetry (TG) analyses were applied to assess the thermal decomposition processes and the non‐isothermal kinetics parameters. The decomposition temperatures of 1–9 are in the range of 190 °C to 374 °C, which of 1, 2 and 3 are higher than 350 °C, 7 possesses the lowest decomposition temperatures. The nitro‐rich ligands advanced the thermal decompositions of these complexes. The sensitivities toward impact and friction were tested according to a standard BAM method, and resulting that all the energetic complexes are much lower sensitive than primary explosive lead azide.