JACS, Wimperis and Ashbrook; NOE enhancement of 11B SSNMR spectra

J. Am. Chem. Soc., ASAP Article 10.1021/ja0610939 S0002-7863(06)01093-6
Web Release Date: May 9, 2006

Nuclear Overhauser Effect (NOE) Enhancement of 11B NMR Spectra of Borane Adducts in the Solid State

Sharon E. Ashbrook, Nicholas G. Dowell, Ivan Prokes, and Stephen Wimperis*

School of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST, United Kingdom, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom, and Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, United Kingdom

Abstract:

A strong 11B {1H} nuclear Overhauser effect (NOE) enhancement can be observed in solid-state 11B NMR spectra of borane adducts, yielding fractional enhancements, fI{S} = (I - I0)/I0, of the magic angle spinning (MAS) NMR signal of up to 155%. This is an interesting and unusual observation as 11B (spin I = 3/2) is a quadrupolar nucleus and the corresponding NOE is completely absent in solution. More generally, it shows that the NOE may have a wider role to play in solid-state NMR studies of dynamics than has been envisaged hitherto.