PMe3-induced CO insertion and CO deinsertion in the zwitterionic hydrocarbyl complex Co2(CO)4 [μ-PhC=C(H)PPh2CC(PPh2)C(O)OC(O)]:: Syntheses and X-ray structures of CO2(CO)3(PMe3)[μ-PhC(CO)=C(H)PPh2C-C(PPh2)C(O)OC(O)] andCo2(CO)3(PMe3)[μ-PhC=C(H)PPh2C=C(PPh2)C(O)OC(O)]

Treatment of the zwitterionic hydrocarbyl compound Co-2(CO)(4)[mu-PhC=C(H)PPh2C=C(PPh2)C(O)OC(O)] (1) with PMe3 leads to CO insertion and formation of the acyl Species Co-2(CO)(3)(PMe3)[mu-PhC(CO)=C(H)PPh2C=C(PPh2)C(O)OC(O)] (2). Compound 2 is unstable at elevated temperatures and loses CO to produce the PMe3-substituted compound Co-2(CO)(3)(PMe3)[mu-PhC=C(H)PPh2C= C(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 (C-13 and P-31) spectroscopies and in the solid state by X-ray diffraction analyses. (c) 2007 Elsevier Ltd. All rights reserved.