Synthesis, Stability Constants and Thermodynamic Parameters of Binary Complexes of Di(2-chlorophenyl) Carbazone

Abstract

The ligand di(2-chlorophenyl) carbazone (DOCIPC) has been synthesised for the first time and characterised by melting point, thin layer chromatography, elemental analysis, mass, ¹H NMR and IR spectra. Stability constants of the complexes of Mn(II), Co(II), Cd(II), Zn(II) , Cu(II), Ni(II) and Fe(II) with DOCIPC have been determined potentiometrically in 50% (v/v) aqueous-dioxane at an ionic strength of 0.1 M NaClO₄ and at different temperatures. The method of Bjerrum and Calvin, as modified by Irving and Rossotti, has been used to find out the values of n and ρL . The stability constants have been calculated using a PC–XT computer by the weighted least squares method. The stability constants have also been calculated by Bjerrum half n method. The order of stability constants is found to be: Mn(II) < Co(II) < Cd(II) < Ni(II) < Zn(II) < Fe(II) < Cu(II). Thermodynamic parameters, ΔG, ΔH and ΔS have been calculated.