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

Abstract

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 633K. 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 lnk=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=298.15K was determined to be 1.42±0.11J·K−1·g−1 by RD496-2000 calorimeter.