Better characterization of surface organometallic catalysts through resolution enhancement in proton solid state NMR spectra.
Delayed-acquisition methods, namely, echo and constant-time-acquisition approaches, allow a significant improvement in resolution in the proton solid state NMR spectra of surface organometallic catalysts such as [syn-(SiO)Mo(=NAr)(=CH(t)Bu)(CH2(t)Bu)] and [(SiO)Re(C(t)Bu)(=CH(t)Bu)(CH2(t)Bu)] (syn/anti ratio = 1:1). This enables the observation of all of the proton resonances, which is not possible with the simple proton single-pulse technique under magic-angle spinning. For example, the methylene protons of the neopentyl ligands, buried in the large peak associated with all of the methyls in the 1H MAS spectrum, can easily be identified by recording a delayed-acquisition spectrum (resolution enhancement of a factor of 3 is obtained). Moreover, combining constant-time acquisition with heteronuclear carbon-proton correlation spectroscopy also improves the resolution of the 2D HETCOR spectra.
Blanc
Frédéric
F
Laboratoire de Chimie Organométallique de Surface, UMR 9986 CNRS - ESCPE Lyon, 43 bd du 11 Novembre 1918, F-69616 Villeurbanne Cedex, France.
Copéret
Christophe
C
Thivolle-Cazat
Jean
J
Basset
Jean-Marie
JM
Lesage
Anne
A
Emsley
Lyndon
L
Sinha
Amritanshu
A
Schrock
Richard R
RR