Scavengers, reagents, and catalysts supported on recyclable magnetic nanoparticles

In this work the immobilization of scavenging groups, reagents, chelating ligands, and catalysts on highly magnetic carbon-coated iron (Fe/C) or cobalt (Co/C) nanoparticles is described. To improve the dispersion stabilities of the nanoparticles and likewise the loading with functional groups, polymers are introduced by surface-initiated polymerization. Successful applications of these novel nanoparticles include the purification of intramolecular Mitsunobu cyclization reactions, the extraction of riboflavin (vitamin B2) from aqueous solutions by immobilized zinc(II)–cyclen complexes, and the preparation of a library of ureas and thioureas exclusively using magnetic scavengers and reagents. The extraordinary high magnetization of the metal core allows for rapid separation of the hybrid materials enabling convenient purification of the reaction mixtures by magnetic decantation. Additionally, the first controlled synthesis of transition-metal nanoparticles on the surface of Co/C nanobeads is described in detail. The synthesized Pd@Co/C nanoparticles are highly active in the hydrogenation of alkenes at atmospheric pressure