Low-Temperature Carbon–Chlorine Bond Activation by Bimetallic Gold/Palladium Alloy Nanoclusters: An Application to Ullmann Coupling

Abstract

This paper describes the unique catalytic activity of bimetallic Au/Pd alloy nanoclusters (NCs) for Ullmann coupling of chloroarenes in aqueous media at low temperature. The corresponding reaction cannot be achieved by monometallic Au and Pd NCs as well as their physical mixtures. On the basis of quantum chemical calculation, it was found that the crucial step to govern the unusual catalytic activity of Au/Pd is the dissociative chemisorption of ArCl, which is unlikely in the monometallic Au and Pd NCs.

Understanding the synergistic effects of gold bimetallic catalysts

“…On one hand, Au is miscible with Pd in all compositions, which offers additional advantages for obtaining a homogeneous Au-Pd nanoalloy phase without much phase segregation. On the other hand, Au-Pd has shown promising performance in a variety of reactions, especially in the selective oxidation of alcohols [44], direct production of H 2 O 2 from H 2 and O 2 [105], and C-C coupling [106]. Very recently, Hutchings and co-workers reported that oxidation of methane to methanol, which is a rather challenging reaction, could be accomplished with Au-Pd alloy catalyst [107].…”

Recent advancement of Ullmann-type coupling reactions in the formation of C–C bond

“…Recently, Sakurai and co-workers achieved an Ullmann coupling of chloroarene under ambient conditions using bimetallic gold-palladium alloy nanoclusters as an effective catalyst and DMF as both a co-solvent and reducing agent [19]. The reaction does not occur with either gold or palladium single-metal clusters alone, nor with a physical mixture of the two metals.…”

2-(diphenylphosphino)pyridine platinum (I) and palladium (I) complex as an efficient binuclear catalyst for Suzuki-Miyaura coupling reaction in water under mild reaction conditions

“…Also, bimetallic Au/ Pd alloy nanoclusters showed excellent reactivity for Ullmann coupling of chloroarenes in aqueous media at low temperature [28,29]. Recently, we have demonstrated synergistic effect between palladium and copper species using copper ferrite supported palladium nanoparticles in cyanation reaction of aryl halides [30].…”