The role of magnetic nanoparticles (MNP) as reducing agents in an MNP-supported Pd-catalyst for the reductive homocoupling of aryl halides

A palladium pincer catalyst grafted onto the surface of magnetic nanoparticles (MNPs) has been developed. This material effectively catalyzes the reductive homocoupling of various aryl halide substrates, with the MNP support acting as the reducing agent. The catalyst can be recycled up to five times in the absence of additional reducing agent to give almost quantitative yields of biaryl homocoupling products. After the reducing power of the MNP has been depleted, the supported Pd complex remains an effective catalyst for Suzuki-Miyaura cross-coupling.