An electronic rationale for observed initiation rates in ruthenium-mediated olefin metathesis: charge donation in phosphine and N-heterocyclic carbene ligands.
Ru K-edge XAS data indicate that second generation ruthenium-based olefin metathesis precatalysts (L = N-heterocyclic carbene) possess a more electron-deficient metal center than in the corresponding first generation species (L = tricyclohexylphosphine). This surprising effect is also observed from DFT calculations and provides a simple rationale for the slow phosphine dissociation kinetics previously noted for second-generation metathesis precatalysts.
The University of British Columbia, Department of Chemistry, Vancouver BC V6T 1Z1.
Kendra
K
Getty
Mario Ulises
MU
Delgado-Jaime
Pierre
P
Kennepohl
D000475:Alkenes / Q000737:chemistry*; D004583:Electrons; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry; D007700:Kinetics; D008024:Ligands; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D010720:Phosphines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
D000475:Alkenes; D006571:Heterocyclic Compounds; D006838:Hydrocarbons; D008024:Ligands; D010720:Phosphines; C030011:carbene; D012428:Ruthenium; C044646:phosphine; D008697:Methane