الفهرس 
Chapter I: IntroductionOnly 14 pages are availabe for public view
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Abstract
The present thesis comprises complexation equilibria and determination of stability constants of binary and ternary complexes with dipicolinic acid (pyridine-2,6-dicarboxylic acid) and inosine as biologically active ligands. Chapter One In the first chapter, aim of the work, description of the role of metal ions in many biological systems and environmental and in-vivo distribution of metals, are summarised. Chapter Two This chapter includes a review of literature of metal complexes of: (a) Pyridinecarboxylic acids, and (b) Nucleosides and nucleotides. Special reference has been given to binary and ternary complexes of dipicolinic acid and of inosine. Chapter Three Chapter three, the experimental part of the thesis and includes a concise survey of materials and reagents used and the procedures carried out for the preparation of different species in solution. The techniques and apparatus are also outlined, as well as. the experimental conditions associated with acid dissociation processes and those concerned with complex formation reactions. Method of calculation is also outlined. Chapter Four In this chapter, the results have been given, explained and [interpreted. The main achievements and views discussed can be [represented as follows :- M11 - dipicolinic acid - glycine systems: The acid-base equilibria of the ligands have been investigated. [The acidity constants of the ligands were determined and used for determining the stability constants of the complexes formed in aqueous solutions under the experimental conditions (t = 25.0°C,µ = 0.10M NaNO3). The dissociation constants of dipicolinic acid were also determined in various water + dioxane mixtures under the same experimental conditions. It is concluded that a pronounced change in the pKa values is observed as the solvent is enriched in dioxane. The binary and ternary complexes of some alkaline earth and transition metal(II) ions [ Mg(II), Ca(Il), Sr(II), Ba(II), Cu(II), Co(II), Ni(II), Zn(Il), Mn(II) and Cd(II) ] with DPA as a primary ligand and glycine as a biologically important secondary ligand were fcudied usisg the potentiometric technique. The results show that in the presence of both ligands, complex formation is conceived to take place in a stepwise manner, i.e., the secondary ligand, glycine starts complexation after the complete formation of the binary 1:1 complex of DPA. The relative stability of the ternary complexes as compared with that of the corresponding binary complexes is expressed in terms of ∆log K. The values of ∆ log K have been evaluated and discussed. In addition, the chelation mode of ternary complexes studied was ascertained by conductivity measurements. Binary and ternary complexes of inosine: The proton association constant of neutral inosine and acidityconstants of some biologically important aliphatic and aromatic carboxylic acids (succinic, oxalic, malic, maleic, malonic, tartaric 5-sulfosalicylic, salicylic and phthalic acids) were determined potiometrically in aqueous solutions under the experimental conditions( t = 25°C,µ = 0.1 M NaN03). Proton - ionization of inosine was assigned to the N1H group with the oxygen at the 6 position assumming the negative charge. Formation of binary and ternary complexes of Cu(II) and Ni(II) metal ions with inosine and aliphatic and aromatic carboxylic acids was studied by the potentiometric technique under the same experimental conditions, e stability constants of 1:1 and 1:2 binary complexes of inosine of carboxylic acids have been determined. Stability constants of | metal:inosine complexes were compared with those of hypoxanthine species. The lower stability of 1:2 complexes of inosine compared to the corresponding 1:1 systems is in accord with staistical considerations. The ternary complex formation was found take place in a stepwise manner with the carboxylic acid acting as primary ligand. Thus, the formation of a ternary complex is ascertained by comparison of the mixed-ligand titration curve with the composite curve obtained by graphical addition of the inosine titraration data to that of the (1:1) Mn-carboxy lie acid titration curve. The stability constants of these ternary systems were calculated. The values of ∆ log K. for the ternary complexes studied have been evaluated and discussed. Another parameter, percent Relative Stabilisation (% R.S.) to quantify the stability of a ternary complex was also evaluated and discussed. In addition, the mode of chelation of some selected ternary complexes was ascertained by conductivity measurements.