A novel compound [Mn(H2O)6](AMTZ)2(PA)2 (AMTZ = 4-amino-3,5-dimethyl-1,2,4-triazole and PA = Picrate) with Extensive hydrogen bonds: Synthesis, structure and thermal characters

The title compound 1, [Mn(H2O)(6)](AMTZ)(2)(PA)(2), contains 4-animo-3,5-dimethyl-1,2,4-triazole (AMTZ) and picrate (PA) and was characterized by elemental analysis, FT-IR spectroscopy and Single-Crystal X-ray diffraction. The space group of compound 1 is triclinic P-1(2), with a = 6.797(2) angstrom, b = 9.800(3) angstrom, c = 13.197(4) angstrom, alpha =, beta =, gamma =. The central Mn2+ is octahedral and surrounded by two kinds of centrosymmetric molecules, AMTZ and PA. The compound has an extended 3-D supramolecular structure due to water molecules coordinated though hydrogen bonds to the nitrogen and oxygen atoms and the offset face-to-face pi center dot center dot center dot pi packing. The differential scanning calorimetry (DSC) analysis shows that two exothermic processes take place at 341.4 degrees C and 473.9 degrees C. The kinetic parameter of the first exothermic process was studied using Kissinger's method and Ozawa's method. This provided the enthalpy of formation (-3337.7 kJ.mol(-1)), critical temperature of thermal explosion (588.79 K). The entropy of activation (Delta S-not equal), enthalpy of activation (Delta H-not equal), and free energy of activation (Delta G(not equal)) were, respectively, -209.78 J.K-1.mol(-1), 155.50 kJ.mol(-1) and 267.75 kJ.mol(-1). A flame sensitivity test showed that the 50% firing height (h(50)) was 20 cm.