Four-Electron Donor Hemilabile n3-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
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Hydride transfer from Cp(CO)2(PPh3)MoH to Ph3C+ BAr'4 [Ar' = 3,5-bis(trifluoromethyl)phenyl] produces [Cp(CO)2(η3 PPh3)Mo]+[BAr'4] . 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 four-electron donor ligand. Computations (DFT/B3LYP and MP2 on [Cp(CO)2(η3 PPh3)Mo]+ and [Cp(CO)2(η3 PH2Ph)Mo]+, and DFT/B3LYP on [Cp(CO)2(η3 PHtBuPh)Mo]+ and [Cp(CO)2(η3 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)]+. The equilibrium constant for [Cp(CO)2(η3 PPh3)Mo]+ + ICH3 to give [Cp(CO)2(PPh3)Mo(ICH3)]+ is Keq = 5.2 x 102 M -1 in CD2Cl2 at 22 °C.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 940220
- Report Number(s):
- PNNL-SA-59787; ORGND7; KC0302010; TRN: US200823%%675
- Journal Information:
- Organometallics, Vol. 27, Issue 15; ISSN 0276-7333
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
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