Copper(II), Nickel and Uranyl Complexes of Some Amino Acids1

The formation constants of copper(II) and nickel complexes of hydroxyproline, asparagine and N,Ndimethylglycine have been obtained. The pK2 of asparagine and the formation constants of its complexes are independeut of the optical configanration. The nickel complexes of serine methyl ester and glycine methyl ester are equally stable, indicating that the serine ester coordinates to the metal ion through the amino group only. At pH 1.90, uranyl ion forms a 1: 1 complex with glycine. In the pH region 3.0 to 4.3, the uranyl ion does not complex with glycine, hydroxyproline, asparagine, N,N- dimethylglycine and serine; only hydrolysis of the uranyl ion occurs.