Structural and catalytic properties of chelating bis- and tris-N-heterocyclic carbenes

The use of polydentate NHC ligands has allowed the preparation of new compounds whose stability is entropically improved by the chelate effect. Chelate-N-heterocyclic ligands also provide interesting features that can allow fine tuning of topological properties such as steric hindrance, bite angles, chirality and fluxional behavior. In this manuscript, we have focused our attention in compounds with chelate-N-heterocyclic ligands in bidentate and tripod coordination forms. Special attention is paid to structural and catalytic properties.