Gas phase enthalpies of formation for potential nitro-substituted borazine high energy materials: A G4MP2 and G4 theoretical study

Abstract

Gas phase (298.15 K, 1 atm) enthalpies of formation ([DELTA]~f~H~(g)~) were calculated at the G4MP2 and G4 levels of theory using the atomization energy approach for various nitro-substituted borazines proposed as high energy materials (HEMs). Modest general agreement was obtained between the G4MP2/G4 atomization energy [DELTA]~f~H~(g)~ estimates and those previously reported using density functional theory methods and homodesmic reaction approaches, with deviations ranging between +9.7 to -56.5 kJ/mol. The results should help constrain the actual enthalpies of formation for these potential HEMs, and suggest the nitroborazines are a particularly challenging case for [DELTA]~f~H~(g)~ calculations using theoretical approaches, requiring high-level composite methods to obtain reliable [DELTA]~f~H~(g)~.