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Abstract Metal ion complex formations are among the prominent interactions in nature, and metal complexation is of widespread interest. It is studied not only by analytical or inorganic chemists, but by physical and organic chemists, and also, by biochemists, pharmacologists, molecular biologists and environmentalists. The purpose of this thesis is studying in depth, the formation of binary and ternary complexes of CuII, CoII, NiII, and ZnII metal ions with some selected triazoles and some biologically important aromatic carboxylic acids, and evaluation of the effect of the temperature of the medium on the stability of some binary and ternary systems. This thesis is organized as follows:- Chapter I: This chapter includes, aim of the work, an introduction to the role of metal ions in biological systems, binary and ternary complex formation, and the role of triazoles in life (biological systems). Chapter II: This chapter is a concerted attempt to outline briefly a concise and complete review of the previous relevant studies conducted on the protonation constants, and formation of binary and ternary complexes of triazoles. Chapter III: This chapter describes the experimental part of this thesis, which includes materials and solutions, experimental techniques, apparatus, procedure and measuring techniques and formation constant calculations. Chapter IV: The acid base properties of the ligands (phthalic acid, anthranilic acid, salicylic acid, 5-sulfosalicylic acid, 1,2,4-triazole, 3-mercapto-1,2,4-triazole and 3-amino-1,2,4-triazole) were investigated and discussed. The acidity constants of the ligands were determined and used for determining the stability constants of the binary and ternary complexes formed in aqueous medium under the experimental conditions (t =25°C and I = 0.10 mol dm-3 NaNO3). The ternary complex formation was found to occur in a stepwise manner. The protonation constants of the investigated ligands and the stability constants of their binary and ternary systems were determined and listed in tables 1-5. The order of stability of the ternary complexes in terms of the nature of aromatic carboxylic acids, triazoles and metal ions is investigated and discussed. The values of ∆logK and logX for the ternary systems have been evaluated and discussed and are allotted in tables 1-5. In addition, evaluation of the effect of temperature of the medium on the stability of the binary and ternary systems (MII-phthalic acid-3-amino-1,2,4-triazole) where (MII = CuII, NiII, and CoII) has been studied. The thermodynamic parameters associated with the dissociation of the ligands studied (phthalic acid and 1,2,4-triazole) and the interaction of metal ions with ligands at 1:1 and at 1:1:1 molar ratio were calculated and discussed and are listed in tables 6,7. |