Evidence for metal-surface interactions and their role in stabilizing well-defined immobilized Ru-NHC alkene metathesis catalysts.
Secondary interactions are demonstrated to direct the stability of well-defined Ru-NHC-based heterogeneous alkene metathesis catalysts. By providing key stabilization of the active sites, higher catalytic performance is achieved. Specifically, they can be described as interactions between the metal center (active site) and the surface functionality of the support, and they have been detected by surface-enhanced (1)H-(29)Si NMR spectroscopy of the ligand and (31)P solid-state NMR of the catalyst precursor. They are present only when the metal center is attached to the surface via a flexible linker (a propyl group), which allows the active site to either react with the substrate or relax, reversibly, to the surface, thus providing stability. In contrast, the use of a rigid linker (here mesitylphenyl) leads to a well-defined active site far away from the surface, stabilized only by a phosphine ligand which under reaction conditions leaves probably irreversibly, leading to faster decomposition and deactivation of the catalysts.
C2P2, UMR 5265, Université de Lyon, Institut de Chimie de Lyon, UMR 5265 CNRS-Université Lyon 1-ESCPE Lyon, LC2P2, Equipe COMS, ESCPE Lyon, 69616 Villeurbanne, France.
Manoja K
MK
Samantaray
Johan
J
Alauzun
David
D
Gajan
Santosh
S
Kavitake
Ahmad
A
Mehdi
Laurent
L
Veyre
Moreno
M
Lelli
Anne
A
Lesage
Lyndon
L
Emsley
Christophe
C
Copéret
Chloé
C
Thieuleux
D002384:Catalysis; D020134:Catalytic Domain; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D017975:Ruthenium Compounds / Q000737:chemistry*; D013499:Surface Properties
D008670:Metals; D017975:Ruthenium Compounds