Synthesis, structure and thermochemical study of a cobalt energetic coordination compound incorporating 3,5-diamino-1,2,4-triazole and pyridine-2,6-dicarboxylic acid

Highlights: • An energetic coordination compound with dinuclear cobalt unit has been synthesized and structurally characterized. • The standard molar enthalpy of formation of the compound was determined by a designed thermochemical cycle. • The specific heat capacity of the compound at T = 298.15 K was determined to be 1.13 ± 0.02 J · mol⁻¹ · K⁻¹. - Abstract: An energetic coordination compound [Co₂(C₂H₅N₅)₂(C₇H₃NO₄)₂(H₂O)₂]·2H₂O (Hdatrz(C₂H₅N₅) = 3,5-diamino-1,2,4-triazole, H₂pda(C₇H₅NO₄) = pyridine-2,6-dicarboxylic acid) has been synthesized and characterized by elemental analysis, chemical analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. X-ray diffraction analysis confirmed that the compound possessed a di-nuclear unit and featured a 3D super-molecular structure. Furthermore, a reasonable thermochemical cycle was designed based on the preparation reaction of the compound and the standard molar enthalpy of dissolution of reactants and products was measured by the RD496-2000 calorimeter. Finally, the standard molar enthalpy of formation of the compound was determined to be −(2475.0 ± 3.1) 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 (1.13 ± 0.02) J · K⁻¹ · g⁻¹ by RD496-2000 calorimeter