Pushing the Limit of Nitro Groups on a Pyrazole Ring with Energy-Stability Balance

Polynitro
compounds exhibit high density and good oxygen balance,
which are desirable for energetic material applications, but their
syntheses are often very challenging. Now, the design and syntheses
of a new three-dimensional (3D) energetic metal–organic framework
(EMOF) and high-energy-density materials (HEDMs) with good thermal
stabilities and detonation properties based on a polynitro pyrazole
are reported. Dipotassium 3,5-bis­(dinitromethyl)-4-nitro-1H-pyrazole (5) exhibits a 3D EMOF structure
with good thermal stability (202 °C), a high density of 2.15
g cm–3 at 100 K (2.10 g cm–3 at
298 K) in combination with superior detonation performance (Dv = 7965 m s–1, P = 29.3 GPa). Dihydrazinium 3,5-bis­(dinitromethyl)-4-nitro-1H-pyrazole (7) exhibits a good density of 1.88
g cm–3 at 100 K (1.83 g cm–3 at
298 K) and superior thermal stability (218 °C), owing to the
presence of 3D hydrogen-bonding networks. Its detonation velocity
(8931 m s–1) and detonation pressure (35.9 GPa)
are considerably superior to those of 1,3,5-trinitro-1,3,5-triazine
(RDX). The results highlight the syntheses of a 3D EMOF (5) and HEDM (7) with five nitro groups as potential energetic
materials.