Functionalised η6-arene ruthenium complexes

η6-Arene ruthenium complexes have been known for more than 30 years, and their chemistry has been extensively studied for unfunctionalised arenes such as benzene, para-cymene and hexamethylbenzene. However, little is known about η6-arene ruthenium complexes in which the arene ligand is not merely an aromatic hydrocarbon but contains chemical functions as substituents. This review gives an overview of functionalised η6-arene ruthenium complexes, their syntheses and structures, as well as their intrinsic potential ranging from biological applications to applications as nano-materials.