Theoretical studies on 2,3,5,6-Tetra(1H-tetrazol-5-yl)pyrazine and 1,1-diamino-2,2-Dinitroethylene blending system

Abstract

To study the properties of 2,3,5,6-tetra(1H-tetrazol-5-yl)pyrazine (H₄TTP) and 1,1'-diamino-2,2'-dinitroethylene (FOX-7) blending system, the structures of H₄TTP, FOX-7, and H₄TTP/FOX-7 dimers were optimized using density functional theory (DFT), and the mechanical properties and cohesive energy densities (CED) of H₄TTP/FOX-7 blends with different mass ratios were calculated by molecular dynamics (MD) simulation. The results show that the HOMO of H₄TTP is distributed on the pyrazine and tetrazole rings, while the LUMO is mainly distributed on the pyrazine ring, with a small contribution from the tetrazole ring. The HOMO of FOX-7 molecules is mainly located on the CC bonds, while the LUMO is mainly located on the nitro groups. The most stable dimer, (I), was formed when the interaction between frontier MOs is possible and hydrogen bond is formed between two monomers, which was confirmed by the Reduced Density Gradient (RDG) isosurface graph. MD studies were carried out to examine the mechanical properties and cohesive energy density of the blending systems. In monomer systems, FOX-7 has the strongest rigidity and best ductility, while H₄TTP has the largest elasticity and best toughness. In the blending systems, we found that various mechanical properties and CED values were different from those of monomers, which improves the sensitivity of H₄TTP and the safety of explosives.

Keywords: 1,1-diamo-2,2-Dinitroethylene (FOX-7); 2,3,5,6-tetra(1H-tetrazol-5-yl)pyrazine (H(4)TTP); Blend; Density functional theory; Mechanical properties; Molecular dynamics.