Abstract
Guanidines have received great attention due to their application as superbasic proton sponges and
organocatalysts, as well as excellent N-donor ligands able to coordinate with different metals. The
introduction of different substituents can modulate the basicity/nucleophilicity of the guanidines, their
coordination ability, and thus, the electronic and steric properties of their metal complexes, regulating their
catalytic activity. This review presents recent developments on guanidine-based ligand families
[monoguanidine, bis(guanidine) and hybrid guanidine ligands], highlighting their potential in transition metalcatalyzed
reactions.