The IR spectrum, crystal structure, electronic structure, thermodynamic properties, heat of formation and detonation properties of a new polynitro heterocyclic energetic material 3,7-bis(dinitromethylene)-2,4,6,8-tetranitro-2,4,6,8-tetraazabicyclo[3.3.0]octane were investigated theoretically. The calculated results show that this compound has a centrosymmetric structure and the molecular packing prediction indicates that the crystalline packing of the title compound is P212121 and the corresponding cell parameters are as follows: Z=4, a= 22.03 Å, b=8.73 Å, c=8.42 Å, Ꮁ=90°, β=90° and γ=90°. Based on the high positive heat of formation (HOF, 740.4 kJ mol-1), excellent detonation properties (detonation velocity D, 9.77 km s−1; detonation pressure P, 45.9 GPa), energy gap (ΔELUMO-HOMO) 4.19 eV and the molecular electrostatic potentials (MEP), it is predicted that 3,7-bis(dinitromethylene)-2,4,6,8-tetranitro-2,4,6,8-tetraazabicyclo[3.3.0] octane could be may be a superior high-energy density compound (HEDC) to RDX and HMX.

Dois materiais energéticos, ricos em nitrogênio, baseados em 1-amino-2-nitroguanidina foram sintetizados. O comportamento térmico, propriedades termo-dinâmicas, estruturas eletrônicas e propriedades de detonação foram investigados. As curvas de calorimetria exploratória diferencial (DSC) mostram que 1-amino-2-nitroguanidina 2,4,5-trinitroimidazol (sal 1) pode ser usado como lançador de explosivos. Essas curvas permitem a determinação dos parâmetros termodinâmicos medidos como energia de ativação (Ek, sal 1, 282,1 kJ mol−1; sal 2, 116,2 kJ mol–1; Eo, sal 1, 275,0 kJ mol–1; sal 2, 116,9 kJ mol–1), entropia de ativação (ΔS≠, sal 1, 395,7 J mol–1 K–1; sal 2, 5,8 J mol–1 K–1), entalpia de ativação (ΔH≠, sal 1, 278,7 kJ mol–1; sal 2, 113,1 kJ mol–1), energia livre de ativação (ΔG≠, sal 1, 117,6 kJ mol–1; sal 2, 110,9 kJ mol–1), calor de formação (∆Hf 0, sal 1, 264,7 kJ mol–1; sal 2, 487,6 kJ mol–1), temperatura crítica de explosão térmica (Tb, sal 1, 412,3 K; sal 2, 388,9 K) implicam que os sais sintetizados são seguros o suficiente durante o estoque ou uso; em vista da pressão de detonação (P, sal 1, 30,2 GPa; sal 2, 29,1 GPa) e da velocidade de detonação (D, sal 1, 8398 m s–1; sal 2, 8334 m s–1), acredita-se que os dois sais baseados em 1-amino-2-nitroguanidina possuem potencial para serem usados como materiais energéticos.

Two nitrogen-rich energetic materials based on 1-amino-2-nitroguanidine were synthesized. The thermal behavior, thermodynamic properties, electron structures and detonation properties were investigated. The dynamic (DSC) curves show that 1-amino-2-nitroguanidinium 2,4,5-trinitroimidazole (salt 1) can be used as cast explosives. These curves allow determination of their melting points and thermodynamic parameters such as activation energy (Ek, salt 1, 282.1 kJ mol–1; alt 2, 116.2 kJ mol–1; Eo, salt 1, 275.0 kJ mol–1; salt 2, 116.9 kJ mol–1), entropy of activation (ΔS≠, salt 1, 395.7 J mol–1 K–1; salt 2, 5.8 J mol–1 K–1), enthalpy of activation (ΔH≠, salt 1, 278.7 kJ mol‑1; salt 2, 113.1 kJ mol–1), free energy of activation (ΔG≠, salt 1, 117.6 kJ mol–1; salt 2, 110.9 kJ mol–1), heat of formation (∆Hf 0, salt 1, 264.7 kJ mol–1; salt 2, 487.6 kJ mol–1) and critical temperature of thermal explosion (Tb, salt 1, 412.3 K; salt 2, 388.9 K), suggesting that the synthesized salts are safe enough during storage or usage. In view of the detonation pressure (P, salt 1, 30.2 GPa; salt 2, 29.1 GPa) and detonation velocity (D, salt 1, 8398 m s–1; salt 2, 8334 m s–1), it is predicted that both 1-amino-2-nitroguanidine-based salts have the potential to be the useful energetic materials.

Density functional theory (DFT) calculations at the B3LYP/6-31G** theoretical level were performed for a series of guanidine-fused bicyclic skeleton derivatives C4N6H8-n(NO2)n (n = 1 - 6). The heats of formation (HOFs) were calculated by isodesmic reactions, and the detonation properties were evaluated using the Kamlet - Jacobs equations. The bond dissociation energies were also analyzed to investigate the thermal stability and sensitivity of the compounds. The results show that all of the derivatives have high positive HOFs, compound G has the highest theoretical density, and compound F1 has the highest detonation velocity and detonation pressure. Considering both the detonation properties and thermal stabilities, compounds D1 and D4 (3 nitro substituents), E1 - E6 (4 nitro substituents), and G (6 nitro substituents) can be regarded as potential candidates for high-energy density materials.