Theoretical research on tricyclic-based as high-energy performance energetic materials

Context: A series of tricyclic high energy density materials (HEDMs) incorporating diazole, triazole, and tetrazole frameworks were systematically investigated through density functional theory (DFT) calculations at the B3LYP/6-31G + + (d,p) and M06-2X/def2-SVP levels. Nitroform-based compounds and fluorodinitromethyl-substituted derivatives were found to exhibit superior densities compared to HMX. Notably, compound II-7 demonstrated the highest predicted density of 2.04 g cm⁻³, along with optimal detonation performance (D = 9451 m s⁻¹, P = 42.57 GPa), surpassing that of HMX. Regarding heat of formation, the tetrazole-based compound III-1 exhibited the highest value of 844.42 kJ mol⁻¹, suggesting enhanced energy content. While nitroform groups improve performance, fluorine substitution offers better stability and sensitivity, representing an effective optimization strategy for energetic materials. Comparative analysis of structures with identical substituents but different parent ring frameworks reveals clear structure property relationships. The incorporation of nitrogen oxygen bonds is shown to significantly enhance performance characteristics. Method: Based on the DFT, molecular optimization and performance metrics analysis were all calculated using the Gaussian 09 package at B3LYP/6-31G + + (d,p) and M06-2X/def2-SVP levels. The electrostatic potential energy and other related calculations were computed using Multiwfn_3.8_dev software. The visualization of the weak interaction between dimers was accomplished using VMD 1.9.3 program.