Standard enthalpy of fusion of N,N′-ethylenebis (2,4-pentanedion-iminoato)nickel(II) complex by DTA-based melting point depression studies

Determination of T-XNi′ diagram for a binary system of N,N′-ethylenebis(2,4-pentanedion-iminoato)nickel(II) (designated as Ni′) and anhydrous bis(2,4-pentanedionato)nickel(II) (designated as Ni″) over the range 1.000-0.749 for the mole fraction (XNi′) of the volatile solvent by employing DTA revealed the system to resemble an ideal eutectic exhibiting lowering of the melting point of the volatile complex Ni′ with the addition of the non-volatile solute Ni″. The thermodynamic correlation between T and XNi′ yielded an average value of 35.0±4.0 kJ mol−1 for the standard enthalpy of fusion of the complex Ni′, upholding the value of 34.70±3.95 kJ mol−1 reported earlier using the TG-based transpiration technique.