Enhanced Thermal Stability of N-Nitrocarbamoyl Derivatives via Triple Synergistic Effect

N -nitrocarbamoyl energetic compounds are high-energy-density materials, while their intrinsically low thermal stability severely limits their practical engineering applications. To address this bottleneck, we herein propose a triple synergistic regulation strategy via conjugated skeleton extension, intramolecular hydrogen bond construction, and intramolecular electrostatic repulsion alleviation to improve the molecular stability of N -nitrocarbamoyl derivatives. A new fused heterocyclic energetic compound NNA-1 was successfully synthesized via a facile one-pot reaction, and its molecular and crystal structure was systematically verified by FTIR, NMR spectroscopy and single-crystal X-ray diffraction (SC-XRD). SC-XRD results demonstrate that the intramolecular hydrogen bonds and favorable molecular planarity of NNA-1 endow it with excellent structural rigidity. Benefiting from the triple synergistic effect, NNA-1 possesses an onset decomposition temperature of 221°C, exceeding the 180°C critical threshold for military energetic materials, and shows better thermal stability than its structurally related analogues NNA-2 and NNA-3. Furthermore, quantum chemical calculations including bond dissociation energy, frontier molecular orbital, LOL-π aromaticity and electrostatic potential analyses elucidate the microscopic origin of its superior stability. This work provides a feasible universal strategy for the rational design of high-stability N -nitrocarbamoyl-based high-energy-density materials.