Bio-catalysts and catalysts based on ruthenium(II) polypyridyl complexes imparting diphenyl-(2-pyridyl)-phosphine as a co-ligand

Reactions of the ruthenium complexes [Ru(κ3-tpy)(PPh3)Cl2], [Ru(κ3-tptz)(PPh3)Cl2] and [Ru(κ3-tpy)Cl3] [tpy = 2,2′:6′,2′′-terpyridine; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine] with diphenyl-(2-pyridyl)-phosphine (PPh2Py) have been investigated. The complexes [Ru(κ3-tpy)(PPh3)Cl2] and [Ru(κ3-tptz)(PPh3)Cl2] reacted with PPh2Py to afford [Ru(κ3-tpy)(κ1-P-PPh2Py)2Cl]+ (1) and [Ru(κ3-tptz)(κ1-P-PPh2Py)2Cl]+ (2), which were isolated as their tetrafluoroborate salts. Under analogous conditions, [Ru(κ3-tpy)Cl3] gave a neutral complex [Ru(κ3-tpy)(κ1-PPh2Py)Cl2] (3). Upon treatment with an excess of NH4PF6 in methanol, 1 and 2 gave [Ru(κ3-tpy)(κ1-P-PPh2Py)(κ2-P,N-PPh2Py)](PF6)2 (4) and [Ru(κ3-tptz)(κ1-P-PPh2Py)(κ2-P,N-PPh2Py)](PF6)2 (5) containing both monodentate and chelated PPh2Py. Further, 4 and 5 reacted with an excess of NaCN and CH3CN to afford [Ru(κ3-tpy)(κ1-P-PPh2Py)2(CN)](PF6) (6), [Ru(κ3-tpy)(κ1-P-PPh2Py)2(NCCH3)](PF6)2 (7), [Ru(κ3-tptz)(κ1-P-PPh2Py)2(CN)]PF6 (8) and [Ru(κ3-tptz)(κ1-P-PPh2Py)2(NCCH3)](PF6)2 (9) supporting hemi labile nature of the coordinated PPh2Py. The complexes have been characterized by elemental analyses, spectral (IR, NMR, electronic absorption, FAB-MS), electrochemical studies and structures of 1, 2 and 3 determined by X-ray single crystal analyses. At higher concentration level (40 μM) the complexes under investigation exhibit inhibitory activity against DNA-Topo II of the filarial parasite S. cervi and 3 catalyses rearrangement of aldoximes to amide under aerobic conditions.