Following the identification of [Ru (η6-p-cymene) Cl2 (1 H, 1 H, 2 H, 2 H-perfluorodecyl-3- (pyridin-3-yl) propanoate)], a ruthenium (II)–arene complex with a perfluoroalkyl-modified ligand that displays remarkable in vitro cancer cell selectivity, a series of structurally related