Tetrazolo[1,5-b]pyridazine as a versatile scaffold for construction of multipurpose energetic materials

In this work, a fused-ring tetrazolo[1,5-b]pyridazine framework with catenated nitrogen chain was applied to develop new energetic materials with task-specific applications for different purposes. Their syntheses, characterizations and properties were extensively studied. Among them,6-methylnitramimo-7-nitro-8-aminotetrazolo[1,5-b]pyridazine (4) is a potential booster explosive with good detonation velocities (D_v: 8496 ​m ​s⁻¹), detonation pressure (p: 28.7 ​GPa), impact sensitivity (IS: 3 ​J), friction sensitivity (FS: 112 ​N) and better decomposition temperature (T_d: 200.7 ​°C) than PETN as well as suitable predicted shock sensitivity (p_{90% TMD}: 1.839 ​GPa). 6-Nitramimo-7-amino-8-nitrotetrazolo[1,5-b]pyridazine (12) is a high-energy explosive (D_v: 8926 ​m ​s⁻¹, p: 33.7 ​GPa), while bis((7-nitro-8-aminotetrazolo[1,5-b]pyridazin-6-yl)amino)ethane (9) is a heat-resistant explosive (T_d: 303.1 ​°C) with high detonation performances (D_v: 8809 ​m ​s⁻¹, p: 29.3 ​GPa) and low sensitivities (IS: 19 ​J, FS: 288 ​N). The analysis of crystal structure, Hirshfeld surface, fingerprint plot, bond dissociation energies (BDEs) and electrostatic potentials (ESP) was used to assess the energy density and sensitivity properties.