Pd(0) encapsulated nanocatalysts as superior catalytic systems for Pd-catalyzed organic transformations

Abstract

In the last decade, Pd(0) nanoparticles have attracted increasing attention due to their outstanding utility as nanocatalysts in a wide variety of key chemical reactions. Remarkably, it has now been well-recognized that the encapsulation of Pd(0) nanoparticles as catalysts in various porous systems can protect the catalyst from deactivation, facilitate its separation and significantly increase its reusability. Encapsulated Pd(0) nanoparticles have also had great impact on the catalytic process in terms of reactivity and selectivity, through imposing confinement effects. In this review, we have tried to underscore the potential advantages associated with various organic, inorganic and hybrid porous systems, such as dendrimers, silica mesoporous systems, MOFs and zeolites, for Pd(0) encapsulation between 2005–2016 and disclose the role of confinement effects on the promotion of catalytic activity of the Pd(0) encapsulated species, which have been used as catalysts in some important organic transformations such as C–C coupling reactions, hydrogenation and oxidation reactions. The advantages and merits provided and observed using the encapsulated Pd(0) nanoparticles are compared with those of the corresponding conventional species. These qualities, particularly in terms of Pd leaching, reusability and activity, are systematically discussed.