Computational Evaluation of Polycyclic Bis-Oxadiazolo-Pyrazine Backbone in Designing Potential Energetic Materials

Abstract

4H,8H-bis[1,2,5]oxadiazolo[3,4-b:3',4'-e]pyrazine (bis-oxadiazolo-pyrazine) represents a versatile CHNO backbone for the design of energetic materials. In this paper, we report a comprehensive computational study using density functional theory to improve detonation properties of this CHNO backbone by introducing pyrazine rings, nitro groups, and N-oxide functionalities. The heat of formation, oxygen balance, density, and detonation properties of a series of furazan-pyrazine fused ring derivatives are computed. Their sensitivity and stability has been correlated with bandgap (ΔE_LUMO-HOMO), maximum heat of detonation (Q), and impact energy (h₅₀). Introduction of –NO₂ and N–oxide on the parent furazan-pyrazine fused ring derivatives is favorable for improving the heat of formation, oxygen balance and density. The heat of formation varies between 464.46 and 1043.57 kJ/mol, and the densities range from 1.75 to 2.01 g/cm³. The positive heat of formation and high densities achieved good detonation velocities (6.74 to 9.61 km/s) and pressures (19.96–43.65 GPa). Among the bis-oxadiazolo-pyrazine derivatives, P5, P6, Q5, Q6, R4, R5, and R6 are fascinating due to their high detonation performances, have calculated detonation velocities and pressures above 9.30 km/s and 40.0 GPa, respectively. Some furazan-pyrazine fused ring derivatives reveal good performance parameters with reasonable stability, confirming them as potential energetic compounds relative to RDX and HMX.

Graphical Abstract

Keywords:

• Fused heterocycles
• Furazan
• heat of formation
• N-oxide
• energetic materials

Acknowledgments

Anjali thank UGC-CSIR, the Ministry of Education, Government of India for the Junior Research Fellowship. SD gratefully acknowledges the support of the Start-up Research Grant (No. SRG/2020/000023) and EMEQ scheme (No. EEQ/2020/000025), Science and Engineering Research Board, Department of Science and Technology, Government of India for research funding.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

VDG thanks Armament Research Board, Defence R&D Organization, DRDO, Government of India for a research [grant no. ARMREB/CDSW/2019/211 and ARMREB/HEM/2021/235].