Synergistic Integration of FOX-7 and HMX Frameworks with Geminal Diamino Bridging: A Computational Exploration of High-Energy, Low-Sensitivity Energetic Materials

Abstract

Progress in the field of energetic materials remains highly challenging because of an inverse relationship between energy output and stability, in which increased performance often reduces stability. In this work, we describe a molecular design strategy that integrates 1,1-diamino-2,2-dinitroethene (FOX-7) with octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) via geminal diamino groups, which are benchmarks for intrinsically insensitive and high-performance materials. The computed results indicate that the synergistic combination of the tetrazocane ring with the FOX-7 structure notably increased the enthalpy of formation (6.76–354.86 kJ/mol) of the designed derivatives (F1–F3) compared to FOX-7 (−88.5 kJ/mol). Further, inserting nitro groups into the tetrazocane ring (compounds F2 and F3), similar to HMX, resulted in elevated detonation velocity (>9.20 km/s) and pressure (>37.5 GPa), in contrast to FOX-7(D= 8.80 km/s; P= 33.6 GPa) and HMX (D= 8.90 km/s; P= 38.4 GPa). Electrostatic potential, noncovalent interactions, Mayer bond orders, QTAIM analysis, and planarity indices were reviewed and compared with FOX-7 and HMX to understand the influence of FOX-7’s push–pull electronic structure and HMX’s powerful strained-ring structure on the stability of the designed compounds. Overall, this work establishes a design principle for coupling FOX-7 and HMX benchmark explosives to balance high energy with manageable sensitivity, thereby serving as modifiable scaffolds for next-generation energetic materials.