PdCl2 Immobilized in polyacrylamide: A low cost and eco-friendly catalyst for suzuki-miyaura reactions

Abstract

PdCl2 immobilized in polyacrylamide (PAM), named Pd/PAM, produced at an extremely low cost, was found to be an efficient catalyst for Suzuki-Miyaura cross-coupling reactions. Iodo- and bromoarenes may couple with phenylboronic acid under eco-friendly conditions (i.e., phosphinefree and with ethanol as the solvent) to give excellent product yields. Aryl chlorides, in contrast, were found to be unsuitable reagents in this context, yielding modest results. The recyclability of Pd/PAM is limited because of PdII leaching, which leaves only the base polymer on the surface after six runs. The Pd/PAM catalyst was initially prepared via the formation of a PAM hydrogel using an aqueous PdCl2 solution. After drying, the solid Pd/PAM was characterized by scanning electron microscopy (SEM), electron-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma optical emission spectrometry (ICP OES).