Anchored complexes of Ni,Pt, and Pd on Fe3O4 nanoparticles as new and eco-friendly nanocatalysts in Suzuki and Heck coupling reactions

Abstract

Three recoverable nanocatalysts were developed by immobilizing Ni, Pt, and Pd Schiff-base complexes on the magnetite nanoparticles. Successful preparation of the nanocatalysts was evidenced by Fourier transform infrared (FT-IR) and energy dispersive X-ray (EDX) spectroscopy. Nano-sized spherical structure of the nanocatalysts was indicated by scanning electron microscopy (SEM). X-ray powder diffraction (XRD) determined that the crystalline cubic spinel structure of Fe₃O₄ remained constant through the synthesis of three complexes on Fe₃O₄ nanoparticles. Magnetic properties of the nanocatalysts were analyzed by the vibration sample magnetometer (VSM). Thermostability of the nanocatalysts was studied by thermogravimetric analysis (TGA). Metal loading of these nanocatalysts was evidenced by inductively coupled plasma atomic emission (ICP-AES).

Investigating the catalytic activity of these nanocatalysts in Suzuki and Heck reactions implicated that in the presence of Pd nanocatalyst coupling reactions proceeded efficiently. For Pt nanocatalyst, Suzuki reaction took place in longer time with moderate to good yield. For the Heck reaction, the desired products were achieved only for aryl iodide and some aryl bromides. The Ni nanocatalyst could just catalyze the Suzuki reaction.

Relying on the magnetic characteristic, these nanocatalysts could be simply recovered and reused several cycles without significant loss in catalytic activity.