Magnetite nanoparticles coated with ruthenium via SePh layer as a magnetically retrievable catalyst for the selective synthesis of primary amides in an aqueous medium.

The nanostructured magnetic oxide Fe3O4 has been coated with silica and then reacted with phenylselenyl chloride under a N2 atmosphere and RuCl3·xH2O successively in an aqueous medium to prepare Fe3O4@SiO2@SePh@Ru(OH)x nanoparticles (NPs) for the first time. These magnetically retrievable NPs have been authenticated using TEM, SEM-EDX and powder-XRD and found to be an efficient catalyst for one pot conversion (organic solvent not required) of aldehydes, nitriles and benzyl amine to primary amides in water. For aldehydes and nitriles, the yields of primary amides are up to 93%. These NPs can be recycled more than 7 times for the conversion of benzonitrile to the corresponding amide. Gram-scale transformation carried out by using Fe3O4@SiO2@SePh@Ru(OH)x NPs as a catalyst gives ∼86% yield.