Cluster chemistry. Part 45. Synthesis and some reactions of [Ru3(µ3-PPhCH2PPh2)(CO)9]– : X-ray crystal structures of [MRu3(µ3-PPhCH2PPh2)(CO)9(PPh3)](M = Cu, Ag, or Au)

Abstract

Reactions between K[BHBu^s₃] and [Ru₃(CO)₁₀(µ-EPh₂CH₂EPh₂)](E = P or As) afford solutions of the dephenylated anions, [Ru₃(µ₃-EPhCH₂EPh₂)(CO)₉]^–, which can be reversibly protonated to give [Ru₃(µ-H)(µ₃-EPhCH₂EPh₂)(CO)₉]. The latter complexes may also be obtained directly from [Ru₃(CO)₁₀(µ-EPh₂CH₂EPh₂)] and H₂(20 atm, 80 °C, 2h) in cyclohexane (yields 65–75%). Similar complexes were obtained in poor yield from [Ru₃(CO)₁₀(µ-PPh₂CH₂CH₂PPh₂)]. The group 1 B metal-containing clusters [MRu₃(µ₃-EPhCH₂EPh₂)(CO)₉(PPh₃)](E = P, M = Cu, Ag, or Au; E = As, M = Au) were prepared from [Ru₃(µ₃-EPhCH₂EPh₂)(CO)₉]^– and sources of [M(PPh₃)]⁺; the analogous [AuRu₃(µ₃-PPhCH₂CH₂PPh₂)(CO)₉(PPh₃)] was also obtained. Single-crystal X-ray studies on the first three, title complexes showed that they are isostructural, the M(PPh₃) fragment bridging the same Ru–Ru bond as that bridged by the PPh group of the face-capping phosphidophosphine ligand. Detailed examination of bond parameters in the Ru₂MP moiety suggests that the three M(PPh₃) fragments are not strictly isolobal, although it is the Ag(PPh₃) fragment which interacts least strongly with the Ru₃ core. The structures were refined by least-squares methods to residuals of 0.039, 0.044, and 0.041 for 4 560, 4 917, and 9 275 independent ‘observed’ reflections, respectively.