A simple and efficient catalyst for Suzuki reaction based on ultra-low palladium chloride supported on ZnO nanowires

Abstract

Zinc oxide nanowires were synthesized and impregnated with trace amounts of palladium ions by adsorption, which was then employed as a heterogeneous catalyst in the Suzuki reaction. To obtain an in-depth understanding of the structure and properties of the ZnO nanowires and the resultant catalyst, different analysis techniques were performed. The as-synthesized catalyst demonstrated exceptional efficiency in promoting the reaction between aryl halides and arylboronic acids, enabling the achievement of biphenyl derivatives in high yields ranging between 82% and 99%. The analysis conducted using transmission electron microscopy demonstrated the formation of palladium nanoparticles during the reaction, confirming their role as the active species driving the catalytic transformation. Further investigation was carried out to examine the effect of the support on the catalytic activity of the catalyst. The results indicated that the morphology and crystallographic structure of zinc oxide had a significant impact on the catalytic activity of the prepared catalyst. The catalytic performance of PdCl2/ZnONWs, where palladium chloride immobilized on ZnO nanowires, was found to be exceptional. The catalyst demonstrated the ability to be recovered and reused up to three times without a noticeable decline in its catalytic activity. Additionally, the loading of palladium species could be reduced to 7.6 mol part per million. Remarkably, the catalyst achieved a total turnover number of 130,000 and a turnover frequency of 0.75 s−1.