Catalytic applications of magnetic nanoparticles functionalized using iridium N-heterocyclic carbene complexes†
A synthetic modular methodology allows the preparation of catalytic materials based on magnetic nanoparticles with iridium N-heterocyclic carbene (NHC) complexes. Imidazolium salts containing a ketone/aldehyde as a pendant functional group are the key species prepared. The condensation reaction of the Cp*IrNHC–CHO compound with magnetic nanoparticles containing amine groups on the surface yields the covalent anchoring of the iridium complex to the surface of the magnetite. The catalytic properties have been evaluated in transfer hydrogenation. The iridium complexes and the material are active in the reduction of ketones using isopropanol as the solvent and hydrogen donor. The catalytic results reveal that the catalytic activity of the material and the molecular complex are equivalent. We have not observed any change in activity due to the support. The recyclability properties of the magnetic material have been evaluated. The results show that the catalyst activity is maintained for two runs. This work describes a simple methodology for anchoring molecular complexes on the surface of magnetic nanoparticles.