Mono- and Bis-cyclopentadienyl Complexes of Ruthenium and Osmium

Synthesis, reactivities, and some applications of mononuclear complexes of ruthenium and osmium bearing a cyclopentadienyl ligand, mainly reported during 2006–20, are summarized according to the geometry of the half-sandwich complexes; pogo stick type, two-legged, three-legged, and four-legged piano stool structures. Properties of sandwich complexes, metallocenes and cationic η6-arene complexes, are also mentioned. Anticancer activities of several complexes are also briefly summarized.