Ruthenium(II)–arene complexes with substituted picolinato ligands: Synthesis, structure, spectroscopic properties and antiproliferative activity

•New organoruthenium complexes have been prepared.•X-ray structure diffraction analyses confirmed piano-stool geometry of complexes.•Some complexes have shown promising in vitro antiproliferative activity.•Complex 7 with isoquinoline-3-carboxylic acid shows distinct activity.•This complex exerted lower cytotoxic activity in normal cells (MRC-5).

A series of seven new ruthenium(II)–arene complexes of general formula [Ru(η6-p-cymene)(L1−7)Cl], where L1−7 are fluoro, chloro, bromo or methyl derivatives of picolinic acid or isoquinoline-3-carboxylic acid has been synthesized and characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy and ESI mass spectrometry. X-ray diffraction studies of two compounds showed the usual piano-stool geometry, with coordination of picolinato ligands through the pyridine nitrogen and the carboxylic group oxygen atom (N/COO− donor set). Cytotoxicity of complexes in vitro has been evaluated in three human tumor cell lines: cervix carcinoma (HeLa), melanoma (FemX), lung adenocarcinoma (A549) and one normal cell line (MRC-5). Complex with isoqinoline-3-carboxylic acid as ligand, exhibited significantly lower cytotoxic activity in normal cells (MRC-5) against high activity observed in panel of tumor cells and prominent cell type selectivity among tumor cells.

Graphical abstractOrganoruthenium complexes containing substituted picolinates have been synthesized and characterized by IR, NMR and mass spectrometry. X-ray diffraction analysis of two compounds showed piano-stool geometry. Cytotoxicity has been evaluated in three tumor and one normal cell line. Complex with isoqinoline-3-carboxylic acid exhibited high cytotoxic activity in investigated tumor cell lines.Figure optionsDownload full-size imageDownload as PowerPoint slide