Synthesis and characterisation of the hexanuclear ruthenium diphosphineclusters[Ru6C(CO)15{µ-Ph2P(CH2)nPPh2}](n = 1–4); crystal structureswhere n = 1–3

Treatment of a hexane solution of the complex [Ru 6 C(CO) 17 ] and 1 equivalent of the organodiphosphine ligands Ph 2 P(CH 2 ) n PPh 2 (n = 1–3) produced the series of derivatives [Ru 6 C(CO) 15 {µ-Ph 2 P(CH 2 ) n PPh 2 }] 1–3, respectively, in ca. 74–94% yield. These clusters have been characterised by IR and NMR spectroscopy and in the solid state by X-ray analyses. The three related compounds all adopt a similar octahedral metal core geometry with the bidentate diphosphine ligand bridging one Ru–Ru edge of the metal polyhedron. Reaction of [Ru 6 C(CO) 17 ] with 1,4-bis(diphenylphosphine)butane, Ph 2 P(CH 2 ) 4 PPh 2 , yielded two products which differ in the mode of bonding of the disphospine ligand, the major product [Ru 6 C(CO) 16 {Ph 2 P(CH 2 ) 4 PPh 2 -P}] 4a in ca. 74% yield and the minor product [Ru 6 C(CO) 15 {µ-Ph 2 P(CH 2 ) 4 PPh 2 }] 4b in ca. 10% yield.