A New View of Relationships of the N–N Bond Dissociation Energies of Cyclic Nitramines. Part I. Relationships with Heats of Fusion

Abstract

The values of bond dissociation energies, BDE, of the weakest N–N bonds and total energies, Etotal, of molecules have been calculated for 14 cyclic nitramines by means of the UB3LYP/6-31G* and UB3LYP/6-31+G* // PM3 methods. The relationships found between the BDE values and values of heat of fusion, ΔHm,tr, of these nitramines are not unambiguous. More unambiguous and logical relationships result from comparison of the BDE/Etotal ratio and the ΔHm,tr values. The dependences found appear suitable for prediction of the ΔHm,tr values for cis-1,3,4,6-tetranitrooctahydroimidazo[4,5-d]imidazole (31.89 kJ mol−1), 4,8,10,12-tetranitro-2,6-dioxa-4,8,10,12-tetraazaisowurtzitane (41.73 kJ mol−1), and 4,6,10,12-tetranitro-2,8-dioxa-4,6,10,12-tetraazaisowurtzitane (41.67 kJ mol−1); the predicted values of ΔHm,tr are within the expected limits and can represent a stabilizing effect of crystal lattice in decomposition reactions of the studied compounds in their molecular crystals.