Satellite-Transition Magic-Angle Spinning

SateUite Transition MAS (SATRAS or STMAS), developed by Gan in 2000 [25], is an alternative approach to MQMAS for the acquisihon of high-resolution NMR spectra of quadrupolar nuclei. The principal advantage of SATRAS over MQMAS is that it is not dependent upon an efficient transfer of multiple-quantum coherences. like MQMAS, SATRAS is a 2D experiment performed under MAS conditions. The technique involves exciting the sateUite transitions in the spin manifold of quadmpolar nuclei using short radio frequency (rf) pulses. The second-order 

This section gives an overview of the recent developments in STMAS spectroscopy. This method is expected to be complimentary to MQMAS in the smdy of materials containing quadrupolar nuclei. 

as indicated in Section 3, correlates the single-qiianttirn satellite transitions to single-quanmm CT leading to an echo of the Fourier transformation which gives rise to high-resolution spectra of half-integer quadrupole spins. A possible correlation is between the l i satellite transitions (ST ) in the fi period of a 2D experiment and the CT in the t2 period. Such a correlation leads to an echo free of the second-order 

Nucleus Material class Substances Year Reference 

Several modifications have been proposed for STMAS. Some were aimed at achieving pure absorption lineshapes such as z-filter ° and phase-modulated shifted-echo schemes.Another modification proposed was to create CT coherences first and detecting the satellite transitions (iSTMAS). ° Perhaps, the most interesting modification involves pure absorption lineshapes with a compensation to the magic-angle misset, the SCAM-STMAS experiment.  

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Satellite transition magic angle spinning (STMAS) Selection of coherences... 

Gan, Z. (2001) Satellite transition magic-angle spinning nuclear magnetic resonance spectroscopy of half-integer... 

S. E. Ashbrook and S. Wimperis, Fligh-resolution NMR of quadrupolar nuclei in solids the satellite-transition magic angle spinning (STMAS) experiment. Prog. Nucl. Magn. Reson. Spectrosc., 2004, 45,53-108. 

S.E. Ashbrook and S. Wimperis, High-Resolution NMR of Quadm-polar Nuclei in Solids The Satellite-Transition Magic Angle Spinning (STMAS) Experiment , p. 53... 

Z. Gan, Isotropic NMR spectra of half-integer quadrupolar nuclei using satellite transitions and magic-angle spinning. /. Am. Chem. Soc., 2000,122,3242-3243. 

Magic Angle Spinning Observation of Satellite Transitions 149... 

Magic angle spinning observation of satellite transitions... 

H. J. Jakobsen, J. Skibsted, H. Bildspe and N. C. Nielsen, Magic-angle spinning NMR spectra of satellite transitions for quadrupolar nuclei in solids. J. Magn. Reson., 1989, 85, 173—180. 

In 2006 Wimperis et al. proposed a method called satellite transitions acquired in real time by MAS (STARTMAS) [142, 202], which allows for the real-time acquisition of high-resolution NMR spectra of spin-3/2 nuclei under MAS. This method combines a train of pulses, similar to CPMG [109, 110], with sample rotation at the magic angle to refocus the quadrupolar broadening in a series of echoes, while allowing the isotropic quadrupolar shift and chemical shift to evolve. 

Correct setting of the magic angle is essential in solid-state NMR spectroscopy. The most commonly used method relies on the Br resonance in solid KBr. Br is a quadrupolar nucleus (spin 3/2) ensuring a short relaxation time. The Br first-order quadmpole coupling on the satellite transition ( 3 /2 1 /2) produces a set of distinct spinning... 

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