ABSTRACT
Whether naturally occurring or synthetic in origin, polymer ligands with metal-coordination atoms, such as oxygen and nitrogen atoms, sometimes show strong and variable metal-ion binding ability, which is closely related to their delicate functions of these polymers. Their coordination behavior is much more sensitive to solution conditions, such as pH and added salt concentration levels, than the simple ligand molecules, whose structures mimic the polymer functional groups. Despite the essential role of metal complexation of these polymer ligands in biological and environmental systems as well as in separation science, very little has so far been disclosed on the equilibrium, kinetic, and structural aspects of the macromolecular complexes. Information gained by systematic studies about simple or oligomeric ligand molecules have not always fully been applied to the chemistry of polymer ligand complexation. In most cases, their experimental results have been interpreted insufficiently and/or improperly because of the neglect of the "polymer effects." Several difficulties encountered in polymer ligand complexation still remain unsolved at the present time, even though the information gained by overall or macroscopic complexation should finally be related to individual or microscopic complexation at a particular reaction site, after correcting for the polymer effects.
