Hydrogel supported vinylimidazole based PEPPSI-Pd-NHC catalysts: The catalytic activities in Heck and Suzuki-Miyaura coupling reactions

Increasing environmental awareness and limited raw material resources have increased the importance of catalysts by leading to green technology. For this purpose, there is a need for efficient, new, selective, reusable, environmentally friendly catalysts and catalytic systems. In this study, PEPPSI (pyridine enhanced precatalyst preparation, stabilization, and initiation) type and vinylimidazole (VI) based palladium complexes of N-heterocyclic carbenes (PEPPSI-Pd-NHCs) which have catalytic activity in homogeneous Suzuki and Heck reactions were prepared. To obtain environmentally safe polymeric heterogeneous catalysts, this novel PEPPSI-Pd-NHC complexes were polymerized with Acrylamide (AAm) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) by free radical polymerization. Characterization of PEPPSI-Pd-NHC complexes and polymer supported catalysts were made by using various elemental and structural analyses techniques. The synthesized polymeric supported heterogeneous catalysts have high activity, stability and reusability for Suzuki and Heck reaction of aryl bromides in aqueous media. (C) 2020 Elsevier B.V. All rights reserved.