Recyclable ionic iron-substituted ceria: a precious metal-free, ligand-free, and versatile catalyst for C-C coupling and -hydroxylation of arylboronic acid.

Fluorite-type nanocrystalline 5% iron-substituted ceria (CeFeO) was synthesized by the solution combustion method with an average crystallite size of 15 nm. The catalyst was well characterized by SEM, EDX, XPS, XRD, and H-TPR studies, which confirmed the substitution of Fe in the CeO lattice. This precious metal-free catalyst was developed for the selective conversion of various arylboronic acids to the corresponding biphenyls and phenols employing KSO and HO, respectively. This catalyst could be coated on cordierite monolith, which acts as a catalyst cartridge employed efficiently in recycling experiments up to seven cycles. The scale-up reaction was also carried out with a catalyst cartridge, affording a good yield of the desired product.