Characterization , Theoretical , Potentiometric , Analytical and Biological Studies on some Thiourea Derivatives and Their Metal Complexes

Abstract

This thesis is focused on the preparation and characterization of new complexes of (Z)-N-benzoyl-N'-(1H-1,2,4-triazol-3-yl)carbamimidothioic acid (H2L1) and N-(benzo[d]thiazol-2-ylcarbamothioyl)benzamide (H2L2) with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and U(VI)O22+ metal ions using elemental analyses, thermal (TGA and DTGA) and different spectroscopic techniques such as spectral (IR, UV-Visible, ESR, EI-mass and NMR), XRD and magnetic measurements. Also, the molecular computational calculation and biological activity were carried out. The proposed chemical formulae of the ligands and their metal complexes are in good agreement with the stoichiometries concluded from their analytical data of carbon, hydrogen, nitrogen, chloride and metal contents. In addition, most of complexes have high melting points (>300˚C) and insoluble in most organic solvents. The coordination sites of the ligand, the nature of metal-ligand bonds, the nature of the acetate groups and the existence of the solvated molecules have been elucidated using FT-IR spectra. Different modes of chelation for the investigated ligands are suggested based on the careful comparison between the spectra of the ligands and their metal complexes. Furthermore, the 1H-NMR spectra of the of Zn(II), Cd(II) and Hg(II) complexes of H2L2 are helpful to detect the molecular structure. The geometries are suggested of the prepared complexes based on the data evaluated from spectral and magnetic measurements; [Zn(HL1)(OAc)(H2O)], [Cd(HL1)Cl(H2O)], [Hg(HL1)Cl(H2O)], [Zn(HL1)Cl].0.5H2O, [Cd(HL2)Cl(H2O)], [Hg(HL2)Cl(H2O)] and [Zn(HL2)2].2H2O are quite near to a tetrahedral geometry predicting sp3 hybridization. On the other hand, [Ni2(HL1)Cl2(H2O)2].4H2O complex showed mixed geometries (tetrahedral and square planar) with sp3 and dsp2