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.