The design of organometallic ruthenium arene anticancer agents

Organometallic half-sandwich Ru-II anticancer complexes of the type [(eta(6)-arene)Ru(yZ)X](n) can exhibit interesting anticancer activity. We review the comparative aqueous solution chemistry (hydrolysis rates, pKa values of aqua complexes), cancer cell cytotoxicities, cross-resistance, reactivity towards nucleobases, DNA and important biomolecules for complexes containing various arenes, N,N- or N,O- or O,O-chelating ligands as YZ, and monodentate leaving groups X. We show that the choice of these ligands can have a dramatic effect on reactivity. The same is true for analogous Os-II arene complexes. The interpretation of structure-activity relationships requires an understanding of reactions of these organometallic complexes under biological test conditions