Abstract
A new EDTA derivative, ethylenediamine tetraacetanilide, has been synthesized and characterised from spectrophotometric (IR, 1H NMR) data. The complexing ability of the ligand to interact with metal cations in water saturated butan-l-ol at 298 K was investigated by uv/visible spectrophotometry and the results obtained show that in this solvent system the new ligand is able to complex copper, cobalt and nickel. The stoichiometry of the complexes determined by using the method of continuous variation (Job's method) indicated the formation of 1:1 (ligand:metal) complexes with Cu(II), Co(II) and Ni(II) in water saturated butan-1-ol. In addition, the presence of a binuclear complex of the type [Cu2L3]4+ is suggested. Thermodynamic data (stability constant, Gibbs energy, enthalpy and entropy) for the complexation of ethylenediamine tetraacetanilide at 298.15 K show a selective sequence in the order Ni2+ > Cu2+ > Co2+, Entropy data reflect the mobility and flexibility of the ligand toward complexation with these metal cations. Furthermore, a higher (more positive) entropy (AcS°) found for the reaction between the ligand and Co(II) suggests the formation of additional chelate rings in the structure of this complex relative to Ni(II) and Cu(II) complexes. Various complexes of ethylenediamine tetraacetanilide have been isolated and characterised by infrared spectroscopy and two of them were analyzed by X-ray diffraction studies. Thus, crystal structure of aqua-ethylenediaimine tetraacetanilide copper(II) perchlorate, [CuL(H2O)](ClO4)2 1.5H2O and aqua-ethylenediamine tetraacetanilide cobalt (II) perchlorate, [CoL(H2O)](ClO4)2 H2O0.5C2H5OH are reported in this thesis. The ability of the ligand to extract metal cations (Cu2+, Ni2+, Co2+, Al3+ and Fe3+) from water to the non-aqueous phase was assessed from distribution data as a function of the hydrogen-ion concentration of the aqueous phase and of the ligand concentration in the organic phase. The data show that copper is selectively extracted over a wide range of hydrogen-ion concentrations in the aqueous phase. Furthermore, plots of distribution data versus the percentage of extracted metal show that at a suitable concentration of ligand, almost 100% of Cu(II) can be extracted by this ligand. A new polymeric material containing ethylenediamine tetraacetanilide as anchor group has been synthesized and the ability of this material to uptake metal cations from water was investigated. Finally, suggestions for further research in this area are given.