Edwin Van Der Eide - Synthesis and Characterization of Cationic Tungsten(V) Methylidynes

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      Publication Details (including relevant citation   information):

      Edwin F. van der Eide, Warren E. Piers, Masood Parvez and Robert   McDonald

      Inorganic   Chemistry   2007, 46, 14-21

      doi:   10.1021/ic0611342

      Abstract:

      Cationic tungsten(V) methylidynes   [L4W(X)CH]+[B(C6F5)4]-  [L = PMe3, 0.5dmpe (dmpe =   Me2PCH2CH2PMe2), X =   Cl, OSO2CF3] have been prepared in high   yield by a one-electron oxidation of the neutral tungsten(IV)   methylidynes L4W(X)CH with   [Ph3C]+[B(C6F5)4]-.   The ease and reversibility of the one-electron oxidation of   L4W(X)CH were demonstrated by cyclic voltammetry in   tetrahydrofuran (E1/2 ≈ −0.68 to −0.91 V vs   Fc). The paramagnetic d1 (S =   1/2) complexes were characterized in   solution by electron spin resonance (g = 2.023−2.048,   quintets due to coupling to 31P) and NMR spectroscopy   and Evans magnetic susceptibility measurements (μ = 2.0−2.1   μB). Single-crystal X-ray diffraction showed that the   cationic methylidynes are structurally similar to the neutral   precursor methylidynes. In addition, the neutral   (PMe3)4W(Cl)CH was deprotonated with a   strong base at the trimethylphosphine ligand to afford   (PMe3)3(Me2PCH2)WCH,   a tungsten(IV) methylidyne complex that features a   (dimethylphosphino)methyl ligand.

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