Physico-Chemical Studies Of Ternary Chelates In Solution: Stability Constant Of Ternary Chelates Of Cu(II),Ni(II),And Co(II)With N-[Tris(Hydroxymethyl)Methyl]Glycine And Various Biologically Relevant Ligands

Author(s): Mohamed Taha*, Mohamed M.Khalil, Alaa T.Ahmed

Summary. Stability constants of ternary complexes of Cu(II), Ni(II), and Co(II)metal ionswithN-[tris(hydroxymethyl)methyl]glycine(tricine) and some aliphatic carboxylic acids(succinic, oxalic, malic, maleic, and tartaric), aromatic carboxylic acids(5-sulfosalicylic, salicylic, and phthalic), and hydroxamic acids(acetohydroxamic acid(Aha), benzohydroxamic acid(Bha), and salicylhydroxamic acid(Sham)) were determined using potentiometric technique at 298.15Kand 0.10mol·dm-3(NaNO3) ionic strength. The stability of the ternary complex is also discussed in relation to that of the binary complexes of secondary ligands. Evaluation of the effect of temperature and ionic strength of the medium on the stability of the ternary system Cu(II)-tricine-the other ligands has been studied. The thermodynamic parameters(G, H, and S ) were studied and discussed. The stability constant of the above-mentioned ternary system has been investigated in(dioxane+water) solution. Confirmation of the ternary complexes in solution has been carried out using differential pulse polarography(DPP), square wave voltammetry, conductometric measurements, and UV-visible spectroscopic measurements.

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