| Abstract
| - Delayed-acquisition methods, namely, echo and constant-time-acquisition approaches, allow a significant improvementin resolution in the proton solid state NMR spectra of surface organometallic catalysts such as [syn-(SiO)Mo(NAr)(CHtBu)(CH2tBu)] and [(⋮SiO)Re(⋮CtBu)(CHtBu)(CH2tBu)] (syn/anti ratio = 1:1). This enables theobservation of all of the proton resonances, which is not possible with the simple proton single-pulse techniqueunder magic-angle spinning. For example, the methylene protons of the neopentyl ligands, buried in the large peakassociated 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-timeacquisition with heteronuclear carbon−proton correlation spectroscopy also improves the resolution of the 2D HETCORspectra.
- Delayed-acquisition methods applied to the proton solid state NMR spectra of surface organometallic catalysts such as [syn-(SiO)Mo(NAr)(CHtBu)(CH2tBu)] and [(⋮SiO)Re(⋮CtBu)(CHtBu)(CH2tBu)] (syn/anti ratio = 1:1) allow a resolution enhancement by a factor of 3 compared to the simple proton single-pulse, which is necessary to observe all of the proton resonances of the spectrum.
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