Reactions of Metal Chelates. I. The Reactions of Copper(II) Chelates of Some β-Diketones and Their Related Compounds with Glycine, Diglycine and Triglycine

The reactions of copper(II) chelates of β-diketones such as acetylacetone, benzoylacetone, dibenzoylmethane and benzoylacetaldehyde and of chelates of their related compounds such as salicylaldehyde and 2-hydroxyacetophenone with glycine or glycylglycine were investigated. Only bis(salicylaldehydato)copper(II) and bis(benzoylacetaldehydato)copper(II) reacted with glycine to form the respective glycinato-Schiff base complexes, whereas the other chelates did not react with glycine under the same condition. On the other hand, all the chelates except bis(dibenzoylmethanato)copper(II) reacted with glycylglycine to form the respective glycylglycinato-Schiff base complexes. The reaction at pH 4.5 between bis(salicylaldehydato)copper(II) and triglycine resulted in the hydrolytic cleavage of peptide bond, producing the salicylideneglycylglycinatocuprate(II) and free glycine. As the results of this investigation, five new copper(II) chelates were synthesized and characterized.