PMe3-induced CO insertion and CO deinsertion in the zwitterionic hydrocarbyl complex Co2(CO)4[μ-PhCC(H)PPh2CC(PPh2)C(O)OC(O)]: Syntheses and X-ray structures of Co2(CO)3(PMe3)[μ-PhC(CO)C(H)PPh2CC(PPh2)C(O)OC(O)] and Co2(CO)3(PMe3)[μ-PhCC(H)PPh2CC(PPh2)C(O

Treatment of the zwitterionic hydrocarbyl compound Co2(CO)4[μ-PhCC(H)PPh2CC(PPh2)C(O)OC(O)] (1) with PMe3 leads to CO insertion and formation of the acyl species Co2(CO)3(PMe3)[μ-PhC(CO)C(H)PPh2CC(PPh2)C(O)OC(O)] (2). Compound 2 is unstable at elevated temperatures and loses CO to produce the PMe3-substituted compound Co2(CO)3(PMe3)[μ-PhCC(H)PPh2CC(PPh2)C(O)OC(O)] (3) as the major product. Compounds 2 and 3 have been isolated and characterized in solution by IR and NMR (13C and 31P) spectroscopies and in the solid state by X-ray diffraction analyses.

Graphical abstractThe zwitterionic hydrocarbyl compound Co2(CO)4[μ-PhCC(H)PPh2CC(PPh2)C(O)OC(O)] (1) reacts with PMe3 to afford the acyl species Co2(CO)3(PMe3)[μ-PhC(CO)C(H)PPh2CC(PPh2)C(O)OC(O)] (2). Decarbonylation of 2 is observed on thermolysis and furnishes a mixture containing the PMe3-substituted compound Co2(CO)3(PMe3)[μ-PhCC(H)PPh2CC(PPh2)C(O)OC(O)] (3) and 1. Compounds 2 and 3 have been isolated and fully characterized by IR and NMR spectroscopies and X-ray diffraction analyses.Figure optionsDownload full-size imageDownload as PowerPoint slide