Satellite-transition MAS NMR of spin I=3/2, 5/2, 7/2, and 9/2 nuclei: Sensitivity, resolution, and practical implementation

被引:61
作者
Ashbrook, SE [1 ]
Wimperis, S [1 ]
机构
[1] Univ Exeter, Sch Chem, Exeter EX4 4QD, Devon, England
关键词
D O I
10.1006/jmre.2002.2557
中图分类号
Q5 [生物化学];
学科分类号
071010 ; 081704 ;
摘要
The satellite-transition MAS (STMAS) experiment offers an alternative approach to established methods such as dynamic angle spinning (DAS), double rotation (DOR), and multiple-quantum MAS (MQMAS) for obtaining high-resolution NMR spectra of half-integer quadrupolar nuclei. Unlike the multiple-quantum experiment, STMAS involves two-dimensional correlation of purely single-quantum coherences; satellite transitions in t(1) (or F-1) and the central transition in t(2) (or F-2). To date, STMAS has primarily been demonstrated for nuclei with spin quantum numbers I = 3/2 and, to a lesser extent, I > 5/2. However, many chemically relevant nuclei possess I > 3/2, such as O-17 and Al-27 (both I = 5/2), Co-59 (I = 7/2), and Nb-93 (I = 9/2). Here, we discuss the application of STMAS to nuclei with spin quantum numbers from I = 3/2 to 9/2. First, we consider the practical implementation of the STMAS experiment using Rb-87(I = 3/2)NMR as an example. We then extend the discussion to include nuclei with higher spin quantum numbers, demonstrating Al-27, Sc-45 (I = 7 /2), Co-59, and Nb-93 STMAS experiments on both crystalline and amorphous samples. We also consider the possibility of experiments involving satellite transitions other than m(I) = 1/2 <-> +/- 3/2 and, using Nb-93 NMR, demonstrate the correlation of all single-quantum satellite transitions up to and including m(I) = +/-7/2 <->+/- 9/2. The absolute chemical shift scaling factors in these experiments are discussed, as are the implications for isotropic resolution. (C) 2002 Elsevier Science (USA).
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页码:269 / 281
页数:13
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