On the track to silica-supported tungsten oxo metathesis catalysts: input from 17O solid-state NMR.
The grafting of an oxo chloro trisalkyl tungsten derivative on silica dehydroxylated at 700 °C was studied by several techniques that showed reaction via W-Cl cleavage, to afford a well-defined precatalyst for alkene metathesis. This was further confirmed by DFT calculations on the grafting process. (17)O labeling of the oxo moiety of a series of related molecular and supported tungsten oxo derivatives was achieved, and the corresponding (17)O MAS NMR spectra were recorded. Combined experimental and theoretical NMR studies yielded information on the local structure of the surface species. Assessment of the (17)O NMR parameters also confirmed the nature of the grafting pathway by ruling out other possible grafting schemes, thanks to highly characteristic anisotropic features arising from the quadrupolar and chemical shift interactions.
Laboratoire de Chimie, Catalyse, Polymères et Procédés, UMR 5265 CNRS/ESCPE-Lyon/UCBL, ESCPE Lyon, F-308-43, Boulevard du 11 Novembre 1918, F-69616 Villeurbanne Cedex, France.
Nicolas
N
Merle
Guillaume
G
Girard
Nicolas
N
Popoff
Aimery
A
De Mallmann
Yassine
Y
Bouhoute
Julien
J
Trébosc
Elise
E
Berrier
Jean-François
JF
Paul
Christopher P
CP
Nicholas
Iker
I
Del Rosal
Laurent
L
Maron
Régis M
RM
Gauvin
Laurent
L
Delevoye
Mostafa
M
Taoufik