Ruthenium(II)–arene complexes with functionalized pyridines: Synthesis, characterization and cytotoxic activity

Ruthenium(II)–arene complexes of general formulae [(η6-p-cymene)Ru(L1–3)Cl2], where L1–3 is 3-acetylpyridine (1), 4-acetylpyridine (2) and 2-amino-5-chloropyridine (3), correspondingly, [(η6-p-cymene)Ru(HL4,5)Cl2], where HL4 and HL5 are respectively isonicotinic acid (4) and nicotinic acid (5) and [(η6-p-cymene)Ru(HL6–9)Cl], where H2L6–9 represent 2,3-pyridinedicarboxylic acid (6), 2,4-pyridinedicarboxylic acid (7), 2,5-pyridinedicarboxylic acid (8) and 2,6-pyridinedicarboxylic acid (9), were prepared by the reaction of [(η6-p-cymene)2RuCl2]2 (10) with the corresponding ligand in 1:2 molar ratio in isopropanol. The complexes were characterized by elemental analysis, mass spectrometry, IR and NMR spectroscopies. According to these data the molecules adopt the usual “three-leg piano-stool” geometry which is common for this type of complexes. The structures of 1 and 7 were determined by X-ray crystallography. The complexes revealed low antiproliferative activity in six investigated tumor cell lines (HeLa, B16, FemX, MDA-MB-361, MDA-MB-453 and LS-174). The reaction of 6 with 9-methyladenine was studied by 1H NMR, 1H, 1H COSY and 1H, 1H NOESY spectroscopy.

Graphical abstractRuthenium(II)–arene complexes with functionalized pyridines were synthesized and characterized by elemental analysis, mass spectrometry, IR and NMR spectroscopy and X-ray crystallography. The cytotoxicity and reaction with 9-methyladenine were investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide