Heats of fusion of polynitro derivatives of polyazaisowurtzitane

Relationships were found between the heats of fusion ΔHm,tr of 12 nitramines with rigid molecules, on one hand, and their molecular weights or their lengths of the longest N–N bonds or 15N NMR chemical shifts of their amine and/or nitro group nitrogen atoms, on the other hand. On the basis of these relationships, the ΔHm,tr values have been predicted for 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW, ΔHm,tr = 42.70 kJ mol−1) and 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX, ΔHm,tr = 36.10 kJ mol−1). It was stated that the HNIW molecule contributes to the intermolecular potential in its molecular crystals mainly by its nitro groups at 2, 6, 8, and 12 positions. The N–N bond length of 0.1377 nm was also predicted for nitramino groupings in 1 and 5 positions of the 1,3,5-trinitro-1,3,5-triazacycloheptane molecule.