Synthesis, thermal and spectral. studies of first-row transition metal complexes with Girard-T reagent-based ligand

The complexing behaviour of 1-acetyltrimethyl ammonium chloride-4-benzoyl thiosemicarbazide (H(2)GTBzIT) towards the following first-row transition metal ions namely, Cr(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) have been examined by elemental analysis, magnetic measurements, electronic, IR and H-1 NMR. The proton-ligand ionization constants were determined potentiometrically using Irving-Rossotti technique. The stability constants of complexes were also calculated and were found in agreement with the sequence of stability constants of Irving and Williams. Thermal properties and decomposition kinetics of all complexes are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters (E, A, Delta H, Delta S and Delta G) of all thermal decomposition stages have been evaluated using Coats-Redfern and Horowitz-Metzger equations. (c) 2007 Elsevier B.V. All rights reserved.