Binuclear dichlorido(eta(6)-p-cymene)ruthenium(II) complexes with bis(nicotinate)- and bis (isonicotinate)-polyethylene glycol ester ligands

Abstract

Neutral binuclear ruthenium complexes 1, 2, 3, 4, 5, 6, 7, 8 of the general formula {[}\{RuCl2((6)-p-cym)\}(2)-(NN)] (NN=bis(nicotinate)- and bis(isonicotinate)-polyethylene glycol esters: (3-py)COO(CH2CH2O)(n)CO(3-py) and (4-py)COO(CH2CH2O)(n)CO(4-py), n =1-4), as well as mononuclear {[}RuCl2((6)-p-cym)((3-py)COO(CH2CH2OCH3)-N)], complex 9, were synthesized and characterized using elemental analysis and electrospray ionization high-resolution mass spectrometry, infrared, H-1 NMR and C-13 NMR spectroscopies. Stability of the binuclear complexes in the presence of dimethylsulfoxide was studied. Furthermore, formation of a cationic complex containing bridging pyridine-based bidentate ligand was monitored using H-1 NMR spectroscopy. Ligand precursors, polyethylene glycol esters of nicotinic (L12HCl-L42HCl and L9HCl) and isonicotinic acid dihydrochlorides (L52HCl-L82HCl), binuclear ruthenium(II) complexes 1, 2, 3, 4, 5, 6, 7, 8 and mononuclear complex 9 were tested for in vitro cytotoxicity against 518A2 (melanoma), 8505C (anaplastic thyroid cancer), A253 (head and neck tumour), MCF-7 (breast tumour) and SW480 (colon carcinoma) cell lines. Copyright (c) 2014 John Wiley \& Sons, Ltd.