Four-electron-donor hemilabile η3-PPh3 ligand that binds through a C=C bond rather than an agostic C-H interaction, and displacement of the C=C by methyl iodide or water

Tan Yun Cheng, David J. Szalda, Jonathan C. Hanson, James T. Muckerman, R. Morris Bullock

Research output: Contribution to journalArticle

10 Citations (Scopus)


Hydride transfer from Cp(CO)2(PPh3)MoH to Ph 3C+BAr′4- [Ar′ = 3,5-bis(trifluoromethyl)phenyl] produces [Cp(CO)23- PPh3)Mo]+[BArVP. Spectroscopic and crystallographic data indicate that one C=C of a Ph ring is weakly bound to the Mo, so that the PPh3 ligand is a four-electron-donor ligand. Computations (DFT/B3LYP and MP2 on [Cp(CO)23-PPh3)Mo]+ and [Cp(CO)2(η-PH2Ph)Mo]+, and DFT/B3LYP on [Cp(CO)23-PHtBuPh)Mo]+ and [Cp(CO)23-PH2Ph)Nb]) provide further information on the bonding and on the preference for bonding of the metal to the C=C bond rather than an agostic C-H interaction found in many related complexes. The hemilabile C=C bond is readily displaced by CH3I or H2O, and crystal structures are reported for [Cp(CO) 2(PPh3)Mo(ICH3)]+ and [Cp(CO) 2(PPh3)Mo(OH2)J+. The equilibrium constant for [Cp(CO)23-PPh3)Mo] + + ICH3 to give [Cp(CO)2(PPh 3)Mo(ICH3)]+ is Keq = 5.2 × 102 M-1 in CD2Cl2 at 22 °C.

Original languageEnglish
Pages (from-to)3785-3795
Number of pages11
Issue number15
Publication statusPublished - Aug 11 2008


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

Cite this