Ruthenium(II) polypyridyl complexes: Potential precursors, metalloligands, and topo II inhibitors

Abstract

Neutral and cationic mononuclear complexes containing both group 15 and polypyridyl ligands [Ru(κ3-tptz)(PPh3)-Cl 2] [1; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-thazine], [Ru(κ3-tptz)(κ2-dppm)CI]BF4 [2; dppm = bis(diphenylphosphino)-methane], [Ru(κ3-tptz)(PPh 3)(pa)]Cl (3; pa = phenylalanine), [Ru(κ3-tptz) (PPh3)(dtc)]Cl (4; dtc = diethyldithiocarbamate), [Ru(κ3-tptz)(PPh3)(SCN)2] (5) and [Ru(κ3-tptz)(PPh3)(N3)2] (6) have been synthesized. Complex 1 has been used as a metalloligand in the synthesis of homo- and heterodinuclear complexes [Cl2(PPh 3)Ru(μ-tptz)Ru-(η6-C6H 6)Cl]BF4 (7), [Cl2(PPh3)Ru(μ- tptz)Ru(η6-C10H14)Cl]PF6 (8), and [Cl2(PPh3)Ru(μ-tptz)Rh(η5-C 5Me5)Cl]BF4 (9). Complexes 7-9 present examples of homo- and heterodinuclear complexes in which a typical organometallic moiety [(η6-C6H6)RuCl]+, [(η6-C10H14)RuCl]+, or [(η5-C5Me5)RhCl]+ is bonded to a ruthenium(II) polypyridine moiety. The complexes have been fully characterized by elemental analyses, fast-atom-bombardment mass spectroscopy, NMR ( 1H and 31P), and electronic spectral studies. Molecular structures of 1-3, 8, and 9 have been determined by single-crystal X-ray diffraction analyses. Complex 1 functions as a good precursor in the synthesis of other ruthenium-(II) complexes and as a metalloligand. All of the complexes under study exhibit inhibitory effects on the Topoisomerase II-DNA activity of filarial parasite Setaria cervi and β-hematin/hemozoin formation in the presence of Plasmodium yoelii lysate. © 2008 American Chemical Society.