Preparation, characterization and first application of silica supported palladium-N-heterocyclic carbene as a heterogeneous catalyst for C–C coupling reactions

Abstract

A novel silica functionalized N-heterocyclic carbene palladium complex was found to be a very efficient and reusable catalyst in the Suzuki and Sonogashira coupling reactions. The synthesized catalyst was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), N₂ adsorption analysis (BET), thermal gravimetric analysis (TGA) and inductively coupled plasma/atomic emission spectroscopy (ICP/AES). The catalysts showed excellent performance in these two reactions including various aryl halide derivatives (except aryl chloride derivatives) with phenylboronic acid and phenylacetylene under green conditions (H₂O). Moreover, the catalyst was recycled for several runs without any significant loss of catalytic activity.