Agarose hydrogel as an effective bioorganic ligand and support for the stabilization of palladium nanoparticles. Application as a recyclable catalyst for Suzuki–Miyaura reaction in aqueous media

Abstract

In this article, the usefulness of an agarose hydrogel as an effective bioorganic ligand and support for the entrapment and stabilization of palladium nanoparticles is described. We have applied this catalyst under low loading of the supported palladium nanoparticles for the Suzuki–Miyaura coupling reaction of different aryl iodides, bromides and chlorides with phenylboronic acid in the absence of phosphorous ligands or any organic co-solvents or phase transfer additives. The catalyst was efficiently recycled for six runs, retaining its activity within the limit of the experimental error. ICP analysis of the catalyst shows Pd content of the agarose hydrogel is a low amount. The analysis of the reaction mixture by the ICP technique also showed the leaching of the catalyst was negligible. The work-up of the mixture can also be handled under highly green conditions in water. However, this catalytic system can be easily applied for scaled-up protocols.