B3LYP calculations on the thermodynamic properties of a series of nitroxycubanes having the formula C8H8-x(NO3)(x) x=1-8.

Recent studies have suggested that octanitrocubane and heptanitrocubane are two of the most powerful non-nuclear high-energy (HE) materials currently known. In this study, we suggest for consideration as new possible HE materials a series of nitroxycubanes, in which the hydrogen atoms on cubane have been progressively substituted for nitrate groups. We hypothesize that these molecules will be good HE materials due to their high nitrogen content and high density, the same reasons nitrocubanes are good high-energy materials. In this study, we predict optimized geometries, vibrational frequencies, enthalpies of formation, and specific enthalpies of combustion. Our results indicate that the enthalpies of formation decrease as the number of nitrate groups increases, which is in direct opposition to what calculations have shown occurs for both the nitroso and the nitrocubane series. Given the difficulty in synthesis of octanitrocubane, octanitroxycubane may still be a more viable candidate for use as a new potential high-energy material.