Crystal Structure and Thermal Properties of N, N'-Bis(2-fluoro-2, 2'-dinitroethyl)-3, 4-diaminofurazan

The single crystal of N, N'-bis(2-fluoro-2, 2'-dinitroethyl)-3, 4-diaminofurazan (LLM-208) was cultivated by solvent evaporation using anhydrous methanol as solvent at the temperature of 10-15℃. Its crystal structure was determined by a X-ray single-crystal diffractometer. Results show that the crystal density of LLM-208 is 1.895 g·cm^-3 at 130 K and 1.848 g·cm^-3 at 298 K, which belongs to monoclinic system, space group C2, a=19.225(5) Å, b=5.5779(15) Å, c=6.4176(17) Å, β=108.551(5)°, V=909.4(6)ų, Z=2, μ=0.192 mm^-1, F(000)=376. Hirshfeld-surface analysis suggests that the dominant contacts and distributions of LLM-208 crystal are shown as follows (R represents ratio): R_O…H/H…O=35.0%, R_O…O=22.3%, R_{F…O/C…F/ F…F}=12.5%. The activation energies calculated by using Kissinger, Flynn-Wall-Ozawa and Starink methods are 112.28, 114.49, 112.49 kJ·mol^-1, respectively. The pre-exponential factor by Kissinger method is 10^21.30 s^-1.