Triruthenium clusters containing bridging dppm and capping sulfido and selenido ligands: X-ray structures of [Ru3(CO)5(μ3-CO)(μ3-Se)(μ-dppm)2], [Ru3(CO)6(μ3-CO)(μ3-Se)(μ-dppm)(η1-Ph2PCH2P(double bond; length as m-dashO)Ph2)] and [Ru2(CO)4(μ-SePh)2(μ-dppm)

The reaction of [Ru3(CO)10(μ-dppm)] (1) with dppmSe at 66 °C affords [Ru3(CO)8(μ-dppm)2] (2), [Ru3(CO)7(μ3-CO)(μ3-Se)(μ-dppm)] (3), [Ru3(CO)5(μ3-CO)(μ3-Se)(μ-dppm)2] (4) and [Ru3(CO)6(μ3-CO)(μ3-Se)(μ-dppm)(η1-Ph2PCH2P(double bond; length as m-dashO)Ph2)] (5) in 7%, 5%, 9% and 33% yields, respectively. A similar reaction between 1 with dppmS gives [Ru3(CO)7(μ3-S)2(μ-dppm)] (6), [Ru3(CO)7(μ3-CO)(μ3-S)(μ-dppm)] (7) [Ru3(CO)5(μ3-CO)(μ3-S)(μ-dppm)2] (8) and [Ru3(CO)6(μ3-CO)(μ3-S)(μ-dppm)(η1-Ph2PCH2P(double bond; length as m-dashO)Ph2)] (9) in 8%, 7%, 14% and 35% yields, respectively. Treatment of 1 with PhSeSePh at 66 °C affords the dinuclear compound [Ru2(CO)4(μ-SePh)2(μ-dppm)] (10) in 14% yield. Thermolysis of 5 and 9in refluxing toluene at 110 °C gives 4 and 8, respectively. The molecular structures of 4, 9 and 10 have been determined by single-crystal X-ray diffraction studies. The cores of the new clusters 4, 5, 8 and 9 consist of metal triangles capped by μ3-sulfur or selenium atoms with the bidentate ligand bridging in equatorial positions. In compounds 4 and 8, two bidentate dppm ligands bridge the Ru3 triangle in such a way that each ligand bridges two ruthenium atoms and one Ru–Ru edge remains unbridged. Compounds 5 and 9 contain one bridging dppm ligand and one dangling dppm mono-oxide ligand Ph2PCH2P(double bond; length as m-dashO)Ph2 coordinated to the rear metal atom at an equatorial position. The molecular structure of 10 shows classical “sawhorse” structure with two bridging SePh ligands as well as the dppm ligand.