Ruthenium(II/III)-based Compounds with Encouraging Antiproliferative Activity against Non-Small Cell Lung Cancer

Hereby we present the synthesis of several Ru(II) and Ru(III) dithiocarbamato complexes proceeding from the Na[trans-RuIII(dmso)2Cl4] (2) and cis-[RuII(dmso)4Cl2] (3) precursors: the diamagnetic mixed-ligand [RuIIL2(dmso)2] (4,5), the paramagnetic neutral [RuIIIL3] monomer (6,7), the antiferromagnetically coupled ionic -[RuIII2L5]Cl (8,9) and -[RuIII2L5]Cl dinuclear species (10,11), where L = dimethyl- (DMDT) and pyrrolidine- (PDT) dithiocarbamate, dmso = dimethyl sulfoxide. All the obtained compounds were fully characterized by elemental analysis, 1H NMR and FT-IR spectroscopy. Moreover, for the first time the crystal structures of the dinuclear -[RuIII2(DMDT)5]BF4∙ CHCl3∙CH3CN and of the novel [RuIIL2(dmso)2] complexes were also determined and discussed. For both the mono- and dinuclear Ru(II) and Ru(III) complexes the central metal(s) assume(s) a distorted octahedral geometry. Furthermore, in vitro cytotoxicity of all the synthetized complexes has been evaluated on non-small cell lung cancer (NSCLC) NCI-H1975 cells. All the mono- and dinuclear Ru(III) dithiocarbamato complexes (6-10) show interesting cytotoxic activity, up to one order of magnitude higher with respect to cisplatin. Otherwise, no significant antiproliferative effect for either the precursors (2,3) or the Ru(II) complexes (4,5) has been observed.