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

Hereby we present the synthesis of several ruthenium(II) and ruthenium(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] complexes 4 and 5, the paramagnetic, neutral [RuIIIL3] monomers 6 and 7, the antiferromagnetically coupled ionic a-[RuIII2L5]Cl complexes 8 and 9 as well as the beta-[RuIII2L5]Cl dinuclear species 10 and 11 (L=dimethyl- (DMDT) and pyrrolidinedithiocarbamate (PDT)) were obtained. All the compounds were fully characterised by elemental analysis as well as 1H NMR and FTIR spectroscopy. Moreover, for the first time the crystal structures of the dinuclear beta-[RuIII2(dmdt)5]BF4 center dot CHCl3 center dot CH3CN and of the novel [RuIIL2(dmso)2] complexes were also determined and discussed. For both the mono- and dinuclear RuII and RuIII complexes the central metal atoms assume a distorted octahedral geometry. Furthermore, in vitro cytotoxicity of the complexes has been evaluated on non-small-cell lung cancer (NSCLC) NCI-H1975 cells. All the mono- and dinuclear RuIII dithiocarbamato compounds (i.e., complexes 610) 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 and 3 or the RuII complexes 4 and 5 has been observed.