Effect of 2-Aminopropanoic Acid on The Formation of Polynuclear Heteroligand Cobalt (Ii) And Nickel (Ii) Complexes

Abstract

Spectrophotometric studies of the Co-(II)-Ni (II)-2-aminopropanoic acid (HAla)-DTPA system have been performed at a variety of reagent molar ratios and pH values. It has been found that, when metal ions are in excess with respect to DTPA at pH 5-9, polyheteronuclear complexes [(CoAla)Dtpa(NiAla)]3–, [(CoAla2) Dtpa(NiAla2)]5–, [(NiAla2)  Dtpa (CoAla2)2]5–, (CoAla2) Dtpa (NiAla2)2]5– and (NiAla2)2Dtpa(CoAla2) 2]5–. form in a solution. The equilibrium constants of formation of these complexes are their overall stability constants have been calculated. Possible structures of the polynuclear complexes are discussed.