CALCULATED PROPERTIES OF THE 22 CARBON NITROGEN CUBANOIDS

Some properties of the 22 possible carbon/nitrogen cubanoids (i.e., (CH)8-nNn 0 less-than-or-equal-to n less-than-equal-to 8) have been calculated and are presented here. By use of the AM1 and PM3 semiempirical models, all the C/N cubanoids are shown to correspond to stationary points on the appropriate energy hypersurfaces. These stationary points are demonstrated to be local stable points via vibrational frequency calculations. The AM1 and PM3 models yield significantly different DELTA-H(f)s, and this disparity increases as the amount of nitrogen in the cubanoid increases. The AM1 and PM3 DELTA-H(f)s are compared with MNDO values and, in a few high-symmetry cases, with RBF/6-31G*//results. The potential of the C/N cubanoids as energetic materials is examined by prediction of two detonation properties of the condensed-phase materials. In order to make these predictions, condensed phase mass densities (rho(o)) are calculated with Stine's method. Then, by use of the rho(o) values and the calculated DELTA-H(f)s, Chapman-Jouguet detonation pressures and velocities are determined. The calculations indicate that any of the C/N cubanoids that contain four nitrogens or more would be high-performance energetic materials. One highly symmetric nitrated cubanoid structure (T(d) symmetry C4(NO2)4N4) is also examined using the same approach.