Treatment of [RuHCl (CO)(AsPh3) 3] with 4′-substituted acetophenone thiosemicarbazone derivatives in methanol under reflux afford a series of air stable new ruthenium (II) cyclometalated complexes containing thiosemicarbazone of general formula [Ru (L)(CO)(AsPh3) 2]. The 4′-substituted acetophenone thiosemicarbazone ligands behave as a dianionic terdentate C, N and S donors (L) and coordinates to ruthenium via aromatic ...