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

A new energetic MOFs , {[Ni 2 (C 2 H 5 N 5 ) 2 (C 3 H 2 O 4 ) 2 (H 2 O)]·3H 2 O} n (Hdatrz (C 2 H 5 N 5 )   =   3,5-diamino-1,2,4-triazole, H 2 mal (C 3 H 4 O 4 )   =   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   ×   10 3 / 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.