Abstract
High-energy density materials (HEDMs) demand precise structural and energetic control to achieve optimal detonation performance, thermal stability, and insensitivity. Now we report a thermally induced rearrangement in the cine-substitution of 1,3,4-trinitropyrazole with 5-aminotetrazole, resulting in two regioisomeric pyrazole-tetrazole frameworks. At room temperature, nucleophilic substitution at the more reactive tetrazole N1-position gave the kinetic product, 1-(3,4-dinitro-1 H-pyrazol-5-yl)-1 H-tetrazol-5-amine (1), which undergoes thermal rearrangement to form a C5-NH-linked thermodynamic isomer, N-(3,4-dinitro-1 H-pyrazol-5-yl)-2 H-tetrazol-5-amine (2) upon heating via a Dimroth-like rearrangement. To enhance performance and safety, compound 2 was converted into energetic salts, with the hydroxylammonium (2b, Dv: 9412 m/s) and hydrazinium salts (2c, Dv: 9441 m/s) exhibiting superior detonation velocities, superior to HMX. Meanwhile, nitration of the kinetic product yielded N-(1-(3,4-dinitro-1 H-pyrazol-5-yl)-1 H-tetrazol-5-yl)nitramide (3), which demonstrated the highest detonation velocity (Dv: 9451 m/s), exceeding HMX, while its energetic salts further improve stability with optimized performance. Additionally, carbonyl azide functionalization of 1 resulted in (3,4-dinitro-1 H-pyrazol-5-yl)carbamoyl azide (4), which displayed the highest detonation properties (Dv: 8799 m/s; P: 33.2 GPa) among carbonyl azides, comparable to RDX. This study highlights thermally controlled regioisomeric switching as a promising strategy for designing safer, high-performance energetic materials.