Carbene complexes. XXII. Preparation, properties and structures of the N,N-functionalized bis(amino)carbenemolybdenum(0) carbonyls and

Article abstract of DOI:10.1016/0022-328X(93)83012-K

Treatment of 1,2-bis(γ-diphenylphosphinopropylamino)ethane yielded the electron-rich enetetramine (CH2)3PPh2>.Although L2^All, the analogue in which R = CH2CH:CH2, is unknown, the carbenemolybdenum title compounds (3) and (4) have been prepared from : for 3 from CH(NMe2)(OMe)2 + 2 and for 4 from L2^(CH2)3PPh2.In 3 only one of the R groups behaves in a ligating mode.L^All being a chelating ligand, 3 is thus a rare example of a metal complex having both carbene- and η²-alkene-ligation and the first for molybdenum.The presumed polymeric structure of 4 is believed to arise from one of the P^III sites behaving in a chelating fashion with the other in a bridging mode.Treatment of 3 with 13CO stereoselectively gave the isotopomer in which a CO trans to a CO was displaced, the trans effect thus being parallel to the trans influence (X-ray data); a coproduct was cis-All)>.Similarly, cis-All)(PEt3)>was the sole product of reaction between 3 and PEt3, which upon irradiation yielded fac- together with .Thermolysis of 3 afforded as the only organic product.The X-ray structure of 3 showed that the mutually trans Mo-CO bonds are significantly longer than Mo-CO trans to carbene <1.984(4) Angstroem> or alkene <1.975(5) Angstroem>, with Mo-C_carb at 2.229(4) Angstroem.