The discovery and optimization of materials with nanometric dimensions (e.g. supported metal clusters) has aroused high interest in catalysis field during the last years. Based on the fact that some elements, such as gold, show unique catalytic properties when properly synthesized in the form of small crystallites, attention has been mainly paid on controlling the physical-chemical characteristics of the supported nanoparticles at atomic scale, taking into account that this matter is crucial for designing more active and selective catalysts. Particularly, the possibilities of supported metal species containing only a small number of atoms (1–10 metal atoms) are of high interest for application in catalysis, since they no longer act like bulk metals, but tend to offer unique properties in the activation of chemical functionalities. During the present project, we will tackle the synthesis, characterization and reactivity of supported metal complexes, and small metal clusters, for producing solid metal-based materials with properties close the molecular analogues. A hypothesis underlying the research is that these well-defined supported species play a key role in advancing the fundamental understanding of catalysis, in such a way that the study of much more complex nanoparticulated materials (industrial catalysts) can be built on the foundation of this research.