Synthesis and characterization of ruthenium and osmium complexes of heterocyclic bidentate ligands (N, X), X = S, Se

The reaction of [RuCl2(PPh3)3] and [OsBr2(PPh3)3] precursors with a series of heterocyclic bidentate (N, X) ligands, X = S, Se, gave complexes [M(R-pyS)2(PPh3)2], (R = H, 3-CF3, 5-CF3, 3-Me3Si); [M(R-pymS)2(PPh3)2], (R = 4-CF3, 4,6-MeCF3) and [M(R-pySe)2(PPh3)2], (R = H, 3-CF3, 5-CF3), where M is Ru or Os, pyS and pymS the anions of pyridine-2-thione and pyrimidine-2-thione, respectively, and pySe is the anion produced by the reductive cleavage of the Se–Se bond in the dipyridyl-2,2′-diselenide. All of the compounds obtained were characterized by microanalysis, IR, FAB, NMR spectroscopy and by cyclic voltammetry. Compounds [Ru(3-CF3-pyS)2(PPh3)2] · 2(CH2Cl2) (2), [Ru(3-Me3Si-pyS)2(PPh3)2] (4), [Ru(4-CF3-pymS)2(PPh3)2] (5), [Ru(3-CF3-pySe)2(PPh3)2] · 2(CH2Cl2) (8), [Os(3-CF3-pyS)2(PPh3)2] · (CHCl3) (11), [Os(3-Me3Si-pyS)2(PPh3)2] (13), [Os(3-CF3-pySe)2(PPh3)2] · 2(CH2Cl2) (17), [Os(5-CF3-pySe)2(PPh3)2] · 2(H2O) (18) and [OsCl2(4,6-MeCF3-pymS)(PPh3)2] (19) were also characterized by X-ray diffraction. In all cases, the metal is in a distorted octahedral environment with the heterocyclic ligand acting as a bidentate (N, S) chelate system.