Cluster chemistry in the Noughties: new developments and their relationship to nanoparticles.

Over the past decade, the chemistry of low-valent transition metal clusters has again come to the fore, primarily as a result of the development of nanochemistry and the realization that large clusters are on the cusp of the nano-domain. This perspective focuses on these recent developments in low-valent transition metal cluster chemistry, specifically looking at cluster-nanoparticles, the use of small and medium sized clusters as nanoparticle precursors, the development of clusters as homogeneous catalysts and hydrogen uptake and storage systems, together with fundamental discoveries relating to novel transformations that can take place within the cluster framework.