A 2D nickel-based energetic MOFs incorporating 3,5-diamino-1,2,4-triazole and malonic acid: Synthesis, crystal structure and thermochemical study

• An energetic MOFs with dinuclear nickel unit has been synthesized and characterized.
• The Arrhenius equation, derived from kinetics analysis, is ln k = 55.89 − 332.01 × 103/RT.
• The standard molar enthalpy of formation of the compound is determined by a thermochemical cycle.
• The molar heat capacity at T = 298.15 K is determined to be 1.42 ± 0.11 J · K−1 · g−1.

A new energetic MOFs, {[Ni2(C2H5N5)2(C3H2O4)2(H2O)]·3H2O}n (Hdatrz (C2H5N5) = 3,5-diamino-1,2,4-triazole, H2mal (C3H4O4) = malonic acid), has been synthesized and characterized by element analysis, chemical analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. X-ray diffraction analysis confirmed that the compound featured a 2D layer structure with dinuclear Ni(II) unit. Thermal analysis demonstrated that the compound after dehydration have good thermostability with decomposition temperature up to 633 K. The non-isothermal kinetics for the compound was studied by Kissinger’s and Ozawa’s methods. The Arrhenius equation of initial thermal decomposition process of compound can be expressed as ln k = 55.89 − 332.01 × 103/RT. Furthermore, a reasonable thermochemical cycle was designed based on the preparation reaction of the compound, and standard molar enthalpy of dissolution of reactants and products were measured by RD496-2000 calorimeter. Finally, the standard molar enthalpy of formation of the compound was determined to be −(2766.3 ± 2.3) kJ · mol−1 in accordance with Hess’s law. In addition, the specific heat capacity of the compound at T = 298.15 K was determined to be 1.42 ± 0.11 J · K−1 · g−1 by RD496-2000 calorimeter.

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