Isomerism in 47- and 48-Electron (Methylidyne)triruthenium Clusters. Crystal Structures¹ of (μ−H)₃Ru3(μ₃−COMe)(CO)₆{μ₃−(PPh₂CH₂)₃CMe} and (μ−H)₃Ru3(μ₃−COMe)(CO)₇{μ₂−(PPh₂)₃CH}•1.25CH₂CI₂

Ligand substitution on (μ−H)₃Ru₃(μ₃−COMe)(CO)₉ has been used to prepare the clusters (μ−H)₃Ru₃-(μ−COMe)(CO)₆(μ₃−(PPh₂CH₂)₃CMe) and (μ−H)₃Ru3(μ₃−COMe)(CO)₇{μ₂−(PPh₂)₃CH}. The complex (μ− H)₃Ru₃(μ₃−COMe)(CO)₆{μ−(PPh₂CH₂)₃CMe} crystallizes in the centrosymmetric triclinic space group P1 with a = 10.053 (2) Å, b = 12.920 (3) Å, c = 19.185 (4) Å, α = 87.23 (2)°, β = 75.80 (2)°, γ = 77.62 (2)°, V = 2359.6 (9) ų, and Z = 2. The molecule has approximate C₃ symmetry, with the μ₃−COMe group and the μ₃−MeC(CH₂PPh₂)₃ ligand capping opposite faces of the planar triruthenium core; the P-donor atoms thus are all in axial sites. Electrochemical and chemical oxidation of (μ−H)₃Ru₃(μ₃−COMe)(CO)₆{μ− (PPh₂CH₂)₃CMe} forms the corresponding 47-electron radical cation, characterized by EPR spectroscopy. The complex (μ−H)₃Ru₃(μ₃−COMe)(CO)₇{μ₂−(PPh₂)₃CH) crystallizes from CH₂C1₂ in the centrosymmetric monoclinic space group P2₁/n with a = 21.653 (6) Å, b = 19.078 (4) Å, c = 25.238 (8) Å, β = 106.63 (3)°, V = 9989 (5) ų, and Z = 8. The crystallographic asymmetric unit contains 2 triruthenium cluster molecules and 2.5 CH₂C1₂ molecules. The (PPh₂)₃CH ligand behaves only as a bidentate bridging ligand and spans adjacent equatorial sites on two ruthenium atoms.