Clickable complexing agents: functional crown ethers for immobilisation onto polymers and magnetic nanoparticles

Crown ethers and monoazacrown ethers supported onto well defined cobalt and Fe₃O₄ magnetic nanoparticles have been prepared and used as magnetically recoverable extracting materials for Pb²⁺ from aqueous and organic solutions. The assembly of the functional nanoparticles involves the integration of the complexing units by means of a copper-catalysed alkyne–azide cycloaddition reaction leading to a 1,2,3-triazole linker. The same binding motifs have been also used to functionalise polystyrene (PS) and polystyrene–polyethyleneglycol (PS–PEG) resins, and the resulting materials were also employed in the removal of Pb²⁺ from solutions. The relative merits of these two approaches are compared.