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Title: SYNTHESIS AND CHARACTERIZATION OF SOME NEW SERIES OF Zn(II), Co(II) AND Cu(II) COMPLEXES OF TETRADENTATE TETRAAZA MACROCYCLES AND PENTAAZA BIS(MACROCYCLES)
Authors: GUTTA, GONFA
Advisors: Prof. Negussie Retta
Copyright: 2002
Date Added: 25-May-2008
Publisher: Addis Ababa University
Abstract: In this study the template synthesis and characterization of two new series of Zn(II), Co(II), and Cu(II) metal complexes of polyaza macrocyclic ligands are presented. In the first part of this work template condensation reaction of o-phenylenediamine with succinic acid in a 1:1 molar ratio in the presence of divalent transition metal ions [Zn(II), Co(II) and Cu(II)], led to the formation of new series of polycrystalline macrocyclic complexes. The synthesis is a remarkably facile one requiring only stirring under room temperature for short period of time. Elemental analysis shows that the complexes have a 1:1 ligand to metal stoichiometry. The absence of bands characteristic of primary amines and carboxylic acids functional groups and the presence of bands characteristic of coordinated secondary amine in the N-H and M-N region gave a strong evidence for the formation of the proposed metal complexes. The 1H and the 13C NMR spectra for Zn(II) complex from the first series also confirm the formation of the macrocyclic frame work. The coordination geometry is found to be octahedral for the Zn(II) and Co(II) complexes and square planar for the Co(II) complex. In the second part of the work, template condensation reaction of p-phenylenediamine, ethyelenediamine, formaldehyde and succinic acid in the presence of metal ions [Zn(II), Co(II) and Cu(II)] produced metal complexes of octahedral geometry of bis(macrocycles) framework. The formation of such series of complexes was confirmed by physico-chemical studies such as elemental analysis for the metal and chlorine, infrared spectroscopy, electronic spectral studies and conductivity data. Lastly, preliminary investigation on the potential hydrolytic nature of the Zn(II) metal complexes revealed that the complexes possess no significant catalytic nature in the hydrolysis of p-nitrophenyl phosphate and carboxylate ester. This is probably due to the presence of elctrophilic carbonyl carbon site on the macocycles of the complex that compete for Zn-OH- nucleophile and thereby deactivating its catalytic activity and the formation of polymeric hydroxide precipitate of the complexes at higher pH.
Description: A Thesis Presented to the School of Graduate Studies Addis Ababa University In partial Fulfillment of the Requirement for the Degree of Master of Science in Chemistry
URI: http://hdl.handle.net/123456789/1228
Appears in:Thesis - Chemistry

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