Design and performance study of nitrogen-containing cuneane derivatives

Abstract

This study introduces nitrogen atoms into the cuneane based on the structural characteristics of β-HMX and ε-CL-20, forming a nitrogen-containing cuneane (CuneaneN) core structure. The compounds CuN-1 to CuN-8 are then designed by modifying the structure with -NO₂ groups. The molecular structure, crystal density, oxygen balance, enthalpy of formation, detonation performance, and safety of these compounds are evaluated using density functional theory (DFT). The results show that as the number of nitro groups increases, the crystal density and enthalpy of formation gradually increase, while the oxygen balance initially increases and then decreases, which affects the detonation performance. Furthermore, the calculations reveal that as the number of nitro groups increases, the sensitization effect within the molecules strengthens, leading to an increase in impact sensitivity and a decrease in thermal stability. Among these compounds, CuN-5 exhibits the best performance (ρ = 1.93 g$·$cm^-3, Q = 1690.47 cal$·$g^-1, D = 9.49 km$·$s^-1, p = 42.47 GPa, BDE of N-NO₂ = 183.94 kJ$·$mol^-1, BDE of C-NO₂ = 279.42 kJ$·$mol^-1, h₅₀ = 9.55 cm). These findings indicate that the construction of nitrogen-containing cage molecules, combined with the modification of energetic groups, can lead to the design of high-energy-density materials with excellent performance and good safety.