l-Methionine–Pd complex supported on hercynite as a highly efficient and reusable nanocatalyst for C–C cross-coupling reactions

Abstract

A “green” method was suggested for the synthesis of hercynite magnetic nanoparticles (MNPs) as a novel heterogeneous catalytic support to immobilize homogeneous complexes. L-Methionine–Pd was immobilized on the surface of hercynite MNPs by a simple, rapid, and convenient route. The structure and composition of the prepared Hercynite@L-Methionine–Pd MNPs were characterized by X-ray diffraction spectroscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectrometry, scanning electron microscopy, X-ray mapping, thermogravimetric analysis and vibrating-sample magnetometry (VSM). Besides, they were applied as green nanocatalysts for Suzuki and Heck cross-coupling reactions. Hercynite@L-Methionine–Pd MNPs offer several advantages (simple synthetic method under green conditions, thermal and chemical stability during organic reactions, short reaction times, high yields of products, excellent selectivity and easy work-up procedure). Moreover, the recycled nanocatalyst was reused for at least five cycles with no significant loss of activity. The hot filtration test indicated heterogeneous catalysis for Suzuki and Heck cross-coupling reactions. This work is useful for the development and application of a magnetically recoverable Pd nanocatalyst on the basis of green-chemistry principles.