BINARY AND TERNARY COMPLEXES OF CD(II) INVOLVING TRIETHYLENETETRAMINEAND SELECTED AMINO-ACIDS AND DNA UNITS

The formation equilibria of the binary complex of cadmium(II) with tri ethylenetetramine (Trien) and of ternary complexes Cd(Trien)L, where L refers to amino acids, DNA constituents and related compounds have be en investigated. Cd(II) was found to form a highly stable complex with Trien. The acid-base equilibria of Cd(Trien)(2+) were characterized. Ternary complexes of amino acids and DNA constituents are formed throu gh stepwise mechanism, whereby Trien binds to Cd(II), followed by inte raction with ligand (L), whereas thiol-containing ligands form ternary complexes through a simultaneous mechanism. The formation constants o f the complexes were determined at 25 degrees C and mu = 0.1M NaNO3. T he participation of different ligand functional groups in the complex- formation was examined.