Studies on the reactivity of the clusters [Ru3(CO)8(μ-H)2(μ-PR2)2] (R=But, Cy) towards phosphine ligands

The reaction behavior of the 48e-clusters [Ru3(CO)8(μ-H)2(μ-PR2)2] (R=But, 1a; R=Cy, 1b) towards phosphine ligands has been studied. Whereas 1a reacts spontaneously with many phosphines at room temperature, a lack of reactivity for 1b under similar conditions is observed. Thus 1a reacts with dppm (Ph2PCH2PPh2) to the known 46e-cluster [Ru3(μ-CO)(CO)4(μ3-H)(μ-H)(μ-PBut2)2(μ-dppm)] (2a), and the reaction of 1a with dppe (Ph2PC2H4PPh2) yields analogously [Ru3(μ-CO)(CO)4(μ3-H)(μ-H)(μ-PBut2)2(μ-dppe)] (3). Reactions of 1a with dmpm (Me2PCH2PMe2), dmpe (Me2PC2H4PMe2) and PBun3, respectively, gave in each case a mixture of products which could not be characterized. Contrary to the reaction behavior at room temperature, 1b reacts with phosphines in THF under reflux yielding the novel complexes [Ru3(CO)6(μ-H)2(μ-PCy2)2L2] (L=Cy2PH, 4a; L=But2PH, 4b; L=Ph2PH, 4c; L=P(OEt)3, 4d). 4a is also obtained directly by the reaction of [Ru3(CO)12] with an excess of Cy2PH. The molecular structure of 4a has been determined by a single-crystal X-ray analysis. Moreover, the thermolysis of 1a in octane affords [Ru3(CO)8(μ-H)2(μ3-PBut)(But2PH)] (6) as the main product, and the thermolysis of [Ru3(CO)9(But2PH)(μ-dppm)] (7) yields 2a to a considerable extent. Treatment of 1a with carbon tetrachloride leads to [Ru3(CO)7(μ-H)(μ-PBut2)2(μ-Cl)] (8) as the main product.

Reactions of the clusters [Ru3(CO)8(μ-H)2(μ-PR2)2] (R=But, 1a; R=Cy, 1b) with various phosphine ligands has been studied. Whereas 1a with (Ph2PC2H4PPh2) (dppe) yields the novel 46e-cluster [Ru3(μ-CO)(CO)4(μ3-H)(μ-H)(μ-PBut2)2(μ-dppm)], 1b reacts with monodentate ligands L in refluxing THF giving the novel complexs [Ru3(CO)6(μ-H)2(μ-PCy2)2L2] (L=Cy2PH, L=But2PH, L=Ph2PH, L=P(OEt)3).Figure optionsDownload as PowerPoint slide