Thermo-responsive poly(N-isopropylacrylamide)-block-poly(ionic liquid) of pyridinium sulfonate immobilized Pd nanoparticles in C–C coupling reactions

Abstract

A thermo-responsive poly(N-isopropylacrylamide)-block-poly(ionic liquid) (PNIPAM-b-PIL) of pyridinium-type was prepared. Initially, controlled synthesis of PNIPAM was performed via RAFT method. Subsequently, PNIPAM as macromolecular chain transfer agent (macro-CTA) was used for fabrication of PNIPAM-b-PIL through reaction with a synthesized IL monomer i.e. 4-vinyl pyridinium propane sulfonate. The Pd catalyst was produced throughout palladium nanoparticles' anchoring into this block copolymer. The catalyst was characterized using ICP, FT-IR, NMR, UV-Vis, TGA, XRD, SEM and EDX techniques. The catalyst's TEM image proved nearly fine dispersion of PdNPs with negligible agglomeration. The catalyst was used in the production of a variety of substituted alkenes and biaryl compounds (Heck and Suzuki coupling) in organic and aqueous media and under solvent free conditions. Additionally, the results signified extreme reusability of the catalyst with a simple recycling procedure.