Transition metal complexes of Vanillin-4N-(2-pyridyl) thiosemicarbazone (H2VPT); thermal, structural and spectroscopic studies

The present work carried out a study on the ligational behavior of the new ligand, Vanillin-4N-(2-pyridyl) thiosemicarbazone (H2VPT) 1 towards some transition metal ions namely, Mn2+, Co2+, Ni2+, Cu2+, Zn2+,Cd2+, Hg2+ and U6+. These complexes namely [Mn(HVPT)Cl] 2, [Co(VPT)(H2O)]2H2O 3, [Ni(HVPT)Cl(H2O)] 4, [Cu(HVPT)Cl(H2O)] 5, [Zn(VPT)(H2O)]H2O 6, [Cd(HVPT)Cl(H2O)] 7, [Hg(VPT)(H2O)]H2O 8 and [UO2(H2VPT)(OAc)2]H2O 9, were characterized by elemental analysis, spectral (IR, 1H NMR and UV–vis) and magnetic moment measurements. The suggested structures were confirmed by applying geometry optimization and conformational analysis.Thermal properties and decomposition kinetics of all compounds are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters (E, A, ΔH, ΔS and ΔG) of all thermal decomposition stages have been evaluated using Coats–Redfern equation. ESR spectra of [Cu(HVPT)Cl]H2O at room temperature show broad signal, indicating spin-exchange interactions between copper(II) ions.