Functionalization of polysterene. II synthesis of chelating polymers by alkylation of 4-aminomethylpolystyrene

A synthetic strategy to obtain chelating polymers via a one-step functionalization of selected macromolecular networks, such as macroporous styrene-divinylbenzene copolymers, is presented. The conversion of chloromethylpolystyrene to aminomethylpolystyrene in a Delepine reaction by way of hexamethylenetetramine addition to the chloride, followed by acid hydrolysis, provides a nucleophilic polymer of high activity. It can be alkylated with a variety of disubstituted benzylhalides (2-acyl-4-chloromethylphenols, 3-picolylchloride, 5-chloromethyl-8-hydroxyquinoline) to yield chelating polymers with strong affinity for transition metal ions. The metal complexing properties of the polymers agree well with estimated properties from known K1 values of the parent ligands in homogenous media. The chelating polymers, 5A, 6A and 7A show very good reversibility in metal binding and release, and good kinetic behaviour due to the hydrophilic nature of the -CH2NHCH2-spacer group between the backbone and the chelating group.