Synthesis and Structural Characterization of the μ-η¹:η⁵-Ph₂PC₅H₄ Ligand-Containing Transition-Metal Cluster and Dinuclear Complexes (μ-η¹:η⁵-Ph₂PC₅H₄)(μ₃-S)MFeCo(CO)₇ (M = Mo, W), (μ-η¹:η⁵-Ph₂PC₅H₄)(μ₃-RC)MCo₂(CO)₇ (M = Mo, W; R = Me, Ph), and (μ-η¹:η⁵-Ph₂PC₅H₄)CpMo₂(CO)₅ Obtained from the Studied Isolobal Displacement Reactions

The isolobal displacement reaction of tetrahedral cluster (μ 3 -S)FeCo 2 (CO) 9 with isolobal reagents η 5 -Ph 2 PC 5 H 4 (CO) 3 MLi (M = Mo, W) in THF at about 60 °C was found to give the μ-η 1:η 5 -Ph 2 PC 5 H 4 -containing tetrahedral clusters (μ-η 1:η 5 -Ph 2 PC 5 H 4 )(μ 3 -S)MFeCo(CO) 7 ( 1, M = Mo; 2, M = W), whereas tetrahedral clusters (μ 3 -RC)Co 3 (CO) 9 (R = Me, Ph) reacted with η 5 -Ph 2 PC 5 H 4 (CO) 3 MLi under the same conditions to afford the corresponding tetrahedral clusters (μ-η 1:η 5 -Ph 2 PC 5 H 4 )(μ 3 -MeC)MCo 2 (CO) 7 ( 3, M = Mo; 4, M = W) and (μ-η 1:η 5 -Ph 2 PC 5 H 4 )(μ 3 -PhC)MCo 2 (CO) 7 ( 5, M = Mo; 6, M = W). However, it was found that when tetrahedral cluster CpMoCo 3 (CO) 11 reacted with isolobal reagent η 5 -Ph 2 PC 5 H 4 (CO) 3 MoLi under similar conditions, the corresponding tetrahedral cluster (μ-η 1:η 5 -Ph 2 PC 5 H 4 )CpMo 2 Co 2 (CO) 9 ( 7 ) was not produced, but instead the dinuclear complex (μ-η 1:η 5 -Ph 2 PC 5 H 4 )CpMo 2 (CO) 5 ( 8 ) was obtained unexpectedly. While 1 − 6 and 8 have been characterized by elemental analysis and spectroscopy, as well as by X-ray crystallography for 1 − 3 and 8, the possible pathways for formation of these products are suggested.