Cytotoxicity and Crystal Structures of Nitrosoruthenium Complexes mer‐[Ru(NO)Py2Cl3] and mer‐[Ru(NO)(γ‐Pic)2Cl3]

The reaction of K2[Ru(NO)Cl5] with excess of pyridine or γ‐picoline in DMF solution at high temperature gives mer‐[Ru(NO)Py2Cl3] (I) and mer‐[Ru(NO)(γ‐Pic)2Cl3] (II), correspondingly, that were obtained with high yields (∼80%) by filtration of concentrated solutions. There is another method for this synthesis that consists of reaction of the same salt with respective heterocycle in water solution with following evaporation with ethanol addition (yield is ∼95%). The crystal structures of the compounds were determined by X‐ray single‐crystal diffraction analysis. Synthesized compounds were characterized by elemental analysis, TGA, IR‐ and NMR‐spectroscopy. The title complexes and related compounds fac‐[Ru(NO)Py2Cl3] (III), cis‐[Ru(NO)Py2Cl2(OH)] (IV), trans‐[Ru(NO)Py2Cl2(OH)] (V), trans‐[Ru(NO)Py4(OH)]Cl2⋅H2O (VI), trans‐[Ru(NO)Py4Cl]Cl2⋅H2O (VII) were examined on cytotoxic activity towards Hep‐2 cancer cell line and HEK‐293 cell line. All the complexes have shown a dose‐dependent cytotoxic effect, complex II has the lowest IC50 value. The synthesis and crystal structure of two novel nitrosoruthenium complexes with pyridine and γ‐picoline mer‐[Ru(NO)Py2Cl3], mer‐[Ru(NO)(γ‐Pic)2Cl3] are reported together with a comparative study of their properties and cytotoxic activity of the title complexes and related compounds fac‐[Ru(NO)Py2Cl3], cis‐[Ru(NO)Py2Cl2(OH)], trans‐[Ru(NO)Py2Cl2(OH)], trans‐[Ru(NO)Py4(OH)]Cl2⋅H2O, trans‐[Ru(NO)Py4Cl]Cl2⋅H2O.