Magnetic nanoparticles supported oxime palladacycle as a highly efficient and separable catalyst for room temperature Suzuki–Miyaura coupling reaction in aqueous media

A novel magnetic nanoparticle-supported oxime palladacycle catalyst was successfully prepared and characterized. The magnetically recoverable catalyst was evaluated in the room temperature Suzuki–Miyaura cross-coupling reaction of aryl iodides and bromides in aqueous media. The catalyst was shown to be highly active under phosphine-free and low Pd loading (0.3 mol%) conditions. The catalyst could be easily separated from the reaction mixture using an external magnet and reused for six consecutive runs without significant loss of activity.

Palladium(II) complexes with a phosphino-oxime ligand: synthesis, structure and applications to the catalytic rearrangement and dehydration of aldoximes

The treatment of [PdCl2(COD)] (COD = 1,5-cyclooctadiene) with 1 and 2 equivalents of 2-(diphenylphosphino)benzaldehyde oxime in dichloromethane at room temperature led to the selective formation of [PdCl2{κ2-(P,N)-2-Ph2PC6H4CH[double bond, length as m-dash]NOH}] (1) and [Pd{κ2-(P,N)-2-Ph2PC6H4CH[double bond, length as m-dash]NOH}2][Cl]2 (2), respectively, which represent the first examples of Pd(II) complexes containing a phosphino-oxime ligand. These compounds, whose structures were fully confirmed by X-ray diffraction methods, were active in the catalytic rearrangement of aldoximes. In particular, using 5 mol% complex 1, a large variety of aldoximes could be cleanly converted into the corresponding primary amides at 100 °C, employing water as solvent and without the assistance of any cocatalyst. Palladium nanoparticles are the active species in the rearrangement process. In addition, when the same reactions were performed employing acetonitrile as solvent, selective dehydration of the aldoximes to form the respective nitriles was observed. For comparative purposes, the catalytic behaviour of an oxime-derived palladacyclic complex has also been briefly evaluated.