Water-Dispersible, Magnetically Recyclable Heterogeneous Cobalt Catalyst for C–C and C–N Cross-Coupling Reactions in Aqueous Media

A cobalt catalyst supported on an iron oxide core, denoted as γ-Fe2O3@PEG@THMAM-Co, has been prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray mapping, thermogravimetry differential thermogravimetry, vibrating sample magnetometry, and inductively coupled plasma. Polyhydroxy end groups in the shell make the catalyst particles dispersible in water, allowing Hiyama, Suzuki, and C–N cross-coupling reactions of aryl iodides and bromides. The catalyst could be recovered by magnetic decantation and reused for at least five successive runs with a negligent decrease in its activity or changes in its morphology. Water as a solvent without requiring additives, surfactants, or organic co-solvents, as well as an abundant and low-cost cobalt catalyst combined with facile recovery, low leaching, and scalability, provides an environmentally and economically attractive alternative to established palladium-catalyzed C–C and C–N coupling reactions.