Tuning In Vitro Cytotoxicity in Diruthenium(I) bis-Cyclopentadienyl Complexes

A series of diruthenium(I) aminocarbyne complexes of general formula Ru2Cp2(CO)(L)(mu-CO){mu-CNMe (Cy)} (L = NH3, 2; Py, 3, PPh3, 4; DMSO, 5; thiourea, 6) and [Ru2Cp2(mu-H)(CO)(2){mu-CNMe (Cy)}], 7, were prepared from the tricarbonyl precursor Ru2Cp2(CO)(2)(mu-CO){mu-CNMe (Cy)}. The reactivity of the diruthenium(I) vinyliminium complex Ru2Cp2(CO)(mu-CO){mu-eta(1):eta(3)-C (Ph)CHCNMe (Cy)}, was also investigated, providing access to piano stool Ru (II) cyclopentadienyl complexes with a five-membered metallacyclic ligand containing sulfur. The new compounds were characterized by IR and multinuclear NMR spectroscopy and X-ray diffraction (in three cases). The solubility in water, lipophilicity, and the speciation of [2-6]CF3SO3 in water/DMSO and cell culture medium are regulated by different monodentate ligands. Subsequently, 1,3-6 were tested in vitro against human ovarian cancer cells (A2780 and A2780cis) and embryonic kidney cells (HEK293), demonstrating moderate to potent cytotoxicity.