Synthesis, Redox Chemistry, and Electronic Structure of the Alkynyl Cyclopentadienyl Molybdenum Complexes [Mo(C≡CR)(CO)(L<sub>2</sub>)Cp′]<sup><i>n</i>+</sup> (<i>n</i> = 0 or 1; R = Ph or C<sub>6</sub>H<sub>4</sub>-4-Me, L<sub>2</sub> = Ph<sub>2</sub>PCH<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub> or 2PMe<sub>3</sub>, Cp′ = Cp or Cp*)
作者:Hannah N. Roberts (née Lancashire)、Neil J. Brown、Ruth Edge、Ross Lewin、David Collison、Paul J. Low、Mark W. Whiteley
DOI:10.1021/om200229c
日期:2011.7.25
Two series of bis-phosphine-substituted cyclopentadienyl molybdenum alkynyl complexes, [Mo (C CR)(CO)(dppe)Cp'] and trans-[Mo(C CR)(CO)(PMe3)(2)Cp'] (R = Ph or C6H4-4-Me, dppe = Ph2PCH2CH2PPh2, Cp' = Cp or Cp*), have been prepared and structurally characterized. One-electron oxidation to the 17-electron radical cations has been investigated by cyclic voltammetry and, for selected Cp* derivatives, by spectroelectrochemical IR and UV-visible methods. Through a combination of experimental measurements (IR and EPR spectroscopy) and DFT-based calculations some important differences between the two series of complexes [Mo(C CR)(CO)(dppe)Cp'] and trans-[Mo(C CR)(CO)(PMe3)(2)Cp'] have been established. In particular, the change in molecular geometry leads to enhanced alkynyl character in the HOMO of [Mo(C CR)(CO)(dppe)Cp'] when compared with the largely metal-centered HOMO of trans-[Mo(C CR)(CO)(PMe3)(2)Cp'].