Comparative theoretical studies of energetic pyrazole-pyridine derivatives.

The pyrazole-pyridine derivatives were optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31G(d,p) and DFT-B3P86/6-31G(d,p) levels. Molecular mechanics (MM) calculations were performed for the title compounds. Heats of formation (HOFs) were predicted through designed isodesmic reactions. Detonation performance was evaluated by using the Kamlet-Jacobs equations based on the calculated densities and heats of formation. The thermal stability of the title compounds was investigated via the bond dissociation energies (BDEs). The simulation results reveal that the compound with one pyrazole ring that is fully nitro-substituted performs similarly to the famous explosive HMX, and the compound with two pyrazole rings that are fully nitro-substituted outperforms HMX. According to the quantitative standard of energetics and stability as high energy density materials (HEDMs), the compound with two pyrazole rings that are fully nitro-substituted essentially satisfies this requirement.