Palladium nanoparticles immobilized by click ionic copolymers: Efficient and recyclable catalysts for Suzuki–Miyaura cross-coupling reaction in water

Abstract

Click reaction of alkyne-functionalized imidazolium salts with azide-containing copolymers gave rise to the click ionic copolymers, subsequent complexation with palladium acetate and reduction using NaBH 4 gave rise to palladium nanoparticles (NPs). The NPs demonstrated high catalytic activity in Suzuki–Miyaura cross-coupling reaction of aryl bromides in pure water. The catalytic system can be used at least five times, no obvious loss of catalytic activity is observed after the reaction. The palladium nanoparticles immobilized by click ionic copolymers exhibit high catalytic stability and recyclability in Suzuki–Miyaura cross-coupling reaction in water. ► Click ionic copolymers are efficient protective agents of palladium NPs. ► The NPs are stabilized by synergetic effect of coordination, electrostatic and steric interactions. ► Suzuki–Miyaura cross-coupling reactions are performed in air and water. ► Palladium NPs can be used at least five times without obvious aggregation.