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

Ashbrook, S.E. and Wimperis, S. (2002) Satellite-transition MAS NMR of spin I=3/2, 5/2, 7/2, and 9/2 nuclei: sensitivity, resolution, and practical implementation. Journal of Magnetic Resonance, 156(2), pp. 269-281. (doi: 10.1006/jmre.2002.2557)

Abstract

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 <i>t</i>1 (or <i>F</i>1) and the central transition in <i>t</i>2 (or <i>F</i>2). To date, STMAS has primarily been demonstrated for nuclei with spin quantum numbers <i>I</i>=3/2 and, to a lesser extent, <i>I</i>>5/2. However, many chemically relevant nuclei possess <i>I</i>>3/2, such as ¹⁷O and ²⁷Al (both <i>I</i>=5/2), ⁵⁹Co (<i>I</i>=7/2), and <i>93</i>Nb (<i>I</i>=9/2). Here, we discuss the application of STMAS to nuclei with spin quantum numbers from <i>I</i>=3/2 to 9/2. First, we consider the practical implementation of the STMAS experiment using ⁸⁷Rb (<i>I</i>=3/2) NMR as an example. We then extend the discussion to include nuclei with higher spin quantum numbers, demonstrating ²⁷Al, ⁴⁵Sc (<i>I</i>=7/2), ⁵⁹Co, and ⁹³Nb STMAS experiments on both crystalline and amorphous samples. We also consider the possibility of experiments involving satellite transitions other than mI=±1/2↔±3/2 and, using ⁹³Nb NMR, demonstrate the correlation of all single-quantum satellite transitions up to and including mI=±7/2↔±9/2. The absolute chemical shift scaling factors in these experiments are discussed, as are the implications for isotropic resolution.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Wimperis, Professor Stephen
• Authors: Ashbrook, S.E., and Wimperis, S.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Magnetic Resonance
• Publisher: Academic Press
• ISSN: 1090-7807
• ISSN (Online): 1096-0856
• Published Online: 06 August 2002