Molecular Design of High Energy Density Materials with Bis(3,4,5-substituted-pyrazolyl)methane Derivatives

A series of bis(3,4,5-substituted pyrazolvl)methane derivatives were designed as candidates of high energy density materials (HEDMs). The heats of formation (HOFs), electronic structure, energetic properties and thermal stabilities were studied using density functional theory (DFT) method. The difluoroamino groups could increase energy gaps of electronic structure, density and detonation properties among the title compounds. Bis[3,5-bis(difluoroamino)-4-nitropyrazolylimethane (C-2) had excellent properties of potential HEDM. Its crystal density (rho, 2.11 g/cm(3)) and impact sensitivity (h(50), 6.8 J) were even higher than those of hexanitrohexaazaisowurtzitane (CL-20), meanwhile its detonation velocity (D, 9.80 km/s) and detonation pressure (P, 46.62 GPa) were very close to CL-20.