Ru(II)-based antimicrobials: looking beyond organic drugs

This review deals with the bactericidal, anti-fungal and even anti-parasitary properties of ruthenium complexes, both inorganic and organometallic, establishing comparisons between these and the available commercial drugs. The description is mostly composed of results found in the literature of the past two decades, complemented with relevant results from our group's research on antimicrobial ruthenium complexes. The complexes are divided into five groups according to the kind of ligands, geometry and chemical nature. The first group comprises ruthenium octahedral complexes with Schiff bases, the most well explored kind of ruthenium antimicrobials. The second group comprises complexes with planar ligands and an overall more flattened geometry, designed for DNA intercalation. In the following two groups, ruthenium complexes feature a particular functionality, which is, in one case, the presence of the PTA ligand for higher solubility in water, and, in the second, the mimicry of an active organic drug. Finally, a small section presents the most recent results on supramolecular antimicrobials comprising ruthenium, in particular a polymer and a cyclodextrin adduct.