Palladium nanoparticles supported on silica, alumina or titania: greener alternatives for Suzuki-Miyaura and other C-C coupling reactions

Most of the catalytic systems for C-C coupling reactions are based on homogeneous catalysts which are normally used only once and do not have a sustainable molecular economy, as they cannot be easily separated from the reaction products to be subsequently recycled and used in other catalytic cycles. The alternative use of heterogeneous catalytic systems,which follow better the principles of green chemistry, is of current environmental and industrial interest for C-C coupling reactions. In this context, although heterogeneous C-C coupling catalysis research has a long history focused on the development of palladium nanoparticles, this field still has several drawbacks to overcome and is an area in continuous evolution, which has developed novel systems based on reusable supported palladium nanoparticles or supported palladium complexes with improved catalytic properties. In this review, the recent research developments of novel hybrid nanostructured materials based on silica, titania and alumina as efficient supports for palladium complexes or palladium nanoparticles are revisited, with special regards to synthetic methodology, characterization methods and catalytic performance. The most relevant results concerning the improvement in the environmental impact of the use of palladium complexes or palladium nanoparticles supported onto silica, titania and alumina reported in the last 10 years on Suzuki-Miyaura and other C-C coupling reactions of interest are also described.