1,2,5-Oxadiazole-1,2,3,4-tetrazole-based high-energy materials: molecular design and screening

Abstract

Various 1,2,5-oxadiazole-1,2,3,4-tetrazole-based high-energy materials were designed and their properties investigated. Their heat of formation, detonation properties, and thermal stability were calculated on the basis of isodesmic reactions, Kamlet-Jacobs equation, and bond dissociation energy, respectively. The results showed that all designed compounds possess high positive heat of formation, and the –N=N–/–N3 substituents were found to be the most effective for improving the heat of formation. The trend of changes in density, detonation pressure, and detonation velocity was almost identical in all compounds, which suggests that density was key to the determination of detonation properties. In view of bond dissociation energy, the –CN/–NH2 substituents improved the thermal stability of the designed compounds, while the other substituents/bridges decreased the stability to some extent. Considering the detonation properties and thermal stability, six compounds (C7, D3, D7, F7, G7, and H7) were selected as potential high-energy materials because they exhibited higher detonation properties and thermal stability than 1,3,5-trinitro-1,3,5-triazinane (RDX). Finally, electronic structures (such as distribution of frontier molecular orbitals and electrostatic potential) of the selected compounds were simulated to obtain detailed information about the electronic structures of the screened compounds.