A computational study of novel nitratoxycarbon, nitritocarbonyl, and nitrate compounds and their potential as high energy materials

The Hartree–Fock RHF/6-31G* and density functional B3LYP/6-31G(d) methods were used to determine the structures and properties of the isomers of the first three members of the series Cn(CO3N)2n+2 (n=0,1,2). The first member of the series, C0(CO3N)2, has six possible isomers, di(nitrato-O-)acetylene, cis- and trans-di(nitrato-O,O-)ethylene, the novel di(nitrato-O,O,O-)ethane or bis(nitratoxycarbon), di(nitroso)oxalate and the mixed isomer nitroso(nitrato-O,O,O-)acetate. The most stable of these isomers, both at the Hartree–Fock or density functional levels of theory, is di(nitroso)oxalate, followed by nitroso(nitrato-O,O,O-)acetate, and bis(nitratoxycarbon). The electronic energy of the mixed isomer closely approximates the mean of the energies of di(nitroso)oxalate and bis(nitratoxycarbon). Neither the cis- nor the trans-di(nitrato-O,O-)ethylene could be optimized to a stable minimum on the Hartree–Fock or density functional potential energy surfaces, and the di(nitrato-O-)acetylene isomer was a stable minimum with the Hartree–Fock method but not at the density functional level of theory. Of the two higher members of the series investigated, Cn(CO3N)2n+2 (n=1,2), each has two isomers: the nitritocarbonyl-substituted systems — analogous to di(nitroso)oxalate — and the nitratoxycarbon-substituted systems (neglecting mixed isomers containing both nitritocarbonyl and nitratoxycarbon moieties). In these compounds, while the nitritocarbonyl derivatives were found to be significantly more stable thermodynamically than the nitratoxycarbon derivatives, both systems were stable minima on both potential energy surfaces and may be of interest as high-energy materials.