Structure and thermodynamic stability of lanthanide complexes with amino acids and peptides

The interaction of lanthanide ions with biologically active ligands is of the utmost relevance to understand and develop new complexes based on these ions. In this paper the thermodynamic and structural properties of Ln(III) complexes with amino acids and peptides is critically reviewed. Mixed-ligand and heteropolynuclear complexes containing amino acids or peptides in the coordination sphere are also included. Equilibrium data in aqueous solution have been collected, showing the formation of species with low thermodynamic stability. The solid state structures are dominated by the formation of carboxylate bridges which connect lanthanide cations. Different nuclearities are found, from discrete dimers to infinite 2D structures.