مطالعه برهمكنش هاي درون مولكولي در كمپلكس سه گانه (Cu (Bpy)( dTDP به روش پتانسومتري

The acidity and stability constants of Cu(dTDP)" (thymidine-5ʹ-diphosphate) and Cu(Bpy)(dTDP)" (2,2ʹ-bipyridyl) complexes, were determined by potentiometric pH titration. It is shown that the stability of the binary Cu(dTDP)" and complexes is determined solely by the basicity of the diphosphate group. It is demonstrated that the equilibrium, Cu(Bpy)2+ + Cu(dTDP)" Cu(Bpy)(dTDP)~ + Cu2+, is displacement is due to the well known experience that mixed ligand complexes formed by a divalent 3d ion, a heteroaromatic N base ansd an O donor ligand possess increased stability. The other part of this displacement, which amount on average to an increased stability of the mixed ligand Cu(Bpy)(dTDP)-complexes of about 0.35 log unit. The stability constants of the 1:1 complexes formed between Cu2+ or Cu(Bpy)2+ and dTDP3- (thymidine-5ʹ-dihosphate), were determined by potentiometric pH titration in aqueous solution (I=-0.1 M,NaNO3, 25°C).