Copper-loaded polymeric magnetic nanocatalysts as retrievable and robust heterogeneous catalysts for click reactions†
A novel heterogeneous copper catalyst based on poly(ionic liquid)-coated magnetic nanoparticles was prepared by the polymerization of 3-carboxymethyl-1-vinylimidazolium in the presence of surface-modified magnetic nanoparticles, followed by the coordination of the carboxylate units in the polymer chains with copper sulfate. The resulting catalyst has a high level of loading of copper ions and is used in low weight percent. The catalytic activity of the newly designed catalyst was tested in a one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles by click reactions between primary halides or tosylates, sodium azide and terminal acetylenes at room temperature in aqueous media. The unique nanocatalyst structure and the multi-layered form of coated polymer on the magnetite surface are responsible for the excellent catalytic performance for click reactions.