A. Medek et L. Frydman, Multiple-quantum magic-angle spinning NMR: A new technique for probing quadrupolar nuclei in solids, J BRAZ CHEM, 10(4), 1999, pp. 263-277
We have recently described a new technique capable of recording high resolu
tion NMR spectra of half - integer quadrupolar nuclei in solid samples, bas
ed on the combined use of magic - angle spinning (MAS) and multiple - quant
um (MQ) spectroscopy(1). This review summarizes the basic theoretical aspec
ts underlying this high resolution MQMAS NMR experiment, emphasizing as wel
l practical aspects involved in the optimization of its signal - to - noise
. We also describe the features of MQMAS spectral lineshapes, and exemplify
these with a number of applications on various quadrupolar nuclei. Also di
scussed is the occurrence of unusual spinning sideband patterns along the m
ultiple - quantum domain; additional references to ongoing progress in the
area that has appeared in the recent literature are also presented.