Dendrimer-encapsulated metal nanoparticles and their applications to catalysis

This account describes the synthesis, characterization, and applications to catalysis of dendrimer-encapsulated metal nanoparticles (DEMNs). These materials are synthesized by a template approach in which metal ions are sorbed into the interior of dendrimers and then subsequently chemically reduced to yield nearly size-monodisperse, zero-valent metal particles having dimensions of less than 4 nm. The dendrimer component of these composites serve not only as a template for preparing the nanoparticle replica, but they also stabilize the nanoparticle, make it possible to tune solubility, and enhance catalytic selectivity. These materials have been used for a broad range of catalytic reactions, including hydrogenations, Heck coupling, and Suzuki reactions. in water, organic solvents, biphasic fluorous/organic solvents, and supercritical CO2. In many cases it is very simple to recycle the dendrimer-encapsulated catalysts. In addition to monometallic DENMs, bimetallic materials have also recently been prepared and their catalytic properties are reported. (C) 2003 Academie des sciences. Published by Editions scientifiques et medicales Elsevier SAS. All rights reserved.