Palladium nanoparticles supported on modified polystyrene resin as a polymeric catalyst for Sonogashira Hagihara coupling reactions

Abstract

Pd(0) nanoparticles supported on modified crosslinked polystyrene were synthesized and characterized. Crosslinked polystyrene was reacted with trioxane and chlorotrimethylsilane in the presence of SnCl 4 to form Merrifield resin. The Merrifield resin was then converted to polymer-bound β -aminoalcohol and subsequently to β - aminophosphinite ligand. This polymeric ligand was reacted with PdCl 2 to obtain a polymeric Pd(0) complex. The TEM image of the Pd catalyst showed good dispersion of catalytic sites. The Pd catalyst exhibits excellent activity and stability in copper-free Sonogashira Hagihara cross-coupling reactions under aerobic conditions. This protocol can be applied efficiently to the coupling reactions of chloro- as well as iodo- and bromo-arenes. The catalyst can be reused several times without any considerable decrease in its activity.