Tuning of cytotoxic activity by bio-mimetic ligands in ruthenium nitrosyl complexes

Three novel ruthenium nitrosyl complexes [Ru(NO)Cl3(InicMe)2] (1b), [RuNOCl3(NicEt)2] (1c) and [RuNOCl3(NicMe)2] (1d) (InicMe = methyl isonicotinate, NicEt = ethyl nicotinate, NicMe = = methyl nicotinate)were prepared and crystal structure of the complexes were determined by single crystal XRD analysis. In all complexes, the organic ligands are coordinated by a pyridine nitrogen atom and located in trans-position each to other and in cis-position to NO group. In the crystal package of all compounds stacking interactions of two types were determined: πarene-πarene and πCOO-πarene stacking. Finally, cytotoxicity of the compounds was tested on Hep2 and HepG2 cell lines. In the set of similar compounds mer-[RuNO(L)2Cl3] (L = Py, γ-Pic, β-Pic, Inic-Alk, Nic-Alk), complexes with iso-nicotinic acid esters are the most toxic, while nicotinic acid derivatives are less toxic and compared with pyridine complex. [Display omitted] •New ruthenium complexes with N-heterocycles were prepared.•Mer-isomers are thermodynamically controlled at the high temperature.•Tiny changes in ligand structure strongly influence the cytotoxicity.