CONDENSATION AS WELL AS TRINUCLEAR PRODUCTS FROM THE REACTION OF TRIRUTHENIUM DODECACARBONYL WITH DIPHENYLPHOSPHINE

The reaction of [Ru3(CO)12] with PPh2H in toluene under reflux affords a range of products, the nature and yields of which depend on the reaction times and the molar ratios employed. Compounds isolated include not only the trinuclear species [Ru3(μ2-PPh2)2(μ2-H)2(CO)8], [Ru3(μ2-PPh2)3(μ2-H)(CO)7], [Ru3(μ2-PPh2)3(μ2-H)(CO)6(PPh2H)], [Ru3(μ3-PPh)(μ-H)2(CO)9] and [Ru3(μ-PPh)(μ-PPh2)2(CO)7] but also condensation products, such as [Ru4(μ4-PPh)2(μ2-CO)(CO)10], [Ru5(μ4-PPh)(CO)15], [Ru6(μ4-PPh)2(μ3-PPh)2(CO)12] and [Ru7(μ4-PPh)2(CO)18], previously isolated from the reaction of [Ru3(CO)12] with PPhH2, as well as the highly unusual octaruthenium derivative [Ru8(μ8-P)(μ2-η1,η6-CH2Ph)(μ2-CO)2(CO)17] and the fragmentation product [Ru2(μ-PPh2)2(CO)6]. The molecular stereochemistries of [Ru2(μ-PPh2)2(CO)6], [Ru3(μ2-PPh2)3(μ2-H)(CO)7], [Ru3(μ2-PPh2)3(μ2-H)(CO)6(PPh2H)] and [Ru8(μ8-P)(μ2-η1,η6-CH2Ph)(μ2-CO)2(CO)17] have been established by X-ray crystallography. The eight ruthenium atoms in the latter adopt a square antiprismatic geometry and encapsulate a phosphorus atom derived from the diphenylphosphine. The benzyl group in this compound exhibits an unusual mode of coordination with the benzene ring functioning as a hexahapto ligand towards one of the ruthenium atoms and with the benzylic carbon bonding directly to an adjacent ruthenium atom. © 1990.