Coordination Versatility of Pyrazole-Based Ligands towards High-Nuclearity Transition-Metal and Rare-Earth Clusters

The synthesis of transition-metal and rare-earth clusters has become a very active research field, mainly because these compounds can behave as molecule-based magnets. The formation of such compounds strongly depends on the choice of the bridging ligand. This review covers the progress made by pyrazole-based ligands in the formation of new transition-metal and rare-earth clusters. Synthetic approaches, structural diversity and magnetic properties are described. The formation of other interesting supramolecular structures, such as metallocycles or metallohelicates is also described to emphasize the richness of this type of ligands.