Osmium Arenes: A New Class of Potential Anti-cancer Agents

Our studies of half-sandwich osmium(II) arene complexes of the type [(η6-arene)Os(XY)Z] show that hydrolysis of the Os–Z (Z = Cl) bond and degree of formation of biologically inactive hydroxo-bridged dimers can be controlled by the choice of the chelated ligand XY. The chemistry and cancer-cell cytotoxicity of complexes containing N,N-, N,O-, or O,O-chelating ligands are compared and contrasted. The wide kinetic timescales of the reactions of these osmium complexes are notable and promising for the design of novel anti-cancer agents.