Heterogeneous High-Loading Hyperbranched Polyglycidol with Peripheral NHC–Pd Complex: Synthesis and Application as Catalyst in Suzuki Coupling Reaction

Abstract

A new polymer-supported highly functionalized dendritic polyether with peripheral NHC–Pd complex was developed by the simple anionic ring opening polymerization of glycidol on bis(3-hydroxypropyl) amine grafted Merrifield resin and its subsequent functional modification of hydroxyl group to NHC–Pd complex. The polymeric material had high stability and swelling capacity in a wide range of solvents, even in water. Similar to supported higher generation dendrimer, the newly developed system showed high palladium content with uniformly distributed and well isolated metal nanocentres. The palladium content was found to be 2.02 mmol/g which was comparatively higher than other heterogeneous NHC–Pd based catalysts and the polymer was used as heterogeneous palladium catalyst for Suzuki coupling reaction. Various factors affecting the catalyst’s performance were studied. The high availability and increased accessibility of catalytic sites, stability and dendrimer like property of the polymeric support, reusability, better resistance to metal leaching, easy synthesis etc. are the important features of this newly synthesized catalytic system.