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)Cl₂] [1; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine], [Ru(κ³-tptz)(κ²-dppm)Cl]BF₄ [2; dppm = bis(diphenylphosphino)methane], [Ru(κ³-tptz)(PPh₃)(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(PPh₃)Ru(μ-tptz)Ru(η⁶-C₆H₆)Cl]BF₄ (7), [Cl₂(PPh₃)Ru(μ-tptz)Ru(η⁶-C₁₀H₁₄)Cl]PF₆ (8), and [Cl₂(PPh₃)Ru(μ-tptz)Rh(η⁵-C₅Me₅)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.