Resin-trapped gold nanoparticles: An efficient catalyst for reduction of nitro compounds and Suzuki-Miyaura coupling

Gold in nanoparticle form shows good catalytic activity in contrast to bulk form and is finding applications in a variety of organic reactions. The present investigation describes direct deposition of gold nanopartides onto commercially available resin by sorption reduction method. Uniformly dispersed nanoparticles of 3-8 nm dimensions were characterized by UV-visible spectroscopy, XRD, SEM and TEM, etc. The AuNPs were found to be remarkably stable and active catalysts for the selective reduction of nitro group under mild reaction conditions and microwave-assisted ligand-free Suzuki-Miyaura cross-coupling reaction between aryl halides and phenylboronic acid. Calculated rate constant (2.5 x 10(-2) s(-1)) for the reduction of 4-nitrophenol is among the best reported in the literature. The versatility of both the protocols is demonstrated by taking a number of substrates. (C) 2013 Elsevier B.V. All rights reserved.