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Deuterium MAS NMR Studies of Dynamics on Multiple Timescales: Histidine and Oxalic Acid |
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| Authors: | Dr Monique Chan‐Huot Prof Stephen Wimperis Prof Christel Gervais Prof Geoffrey Bodenhausen Dr Luminita Duma |
| Institution: | 1. Laboratoire des BioMolécules, UMR 7203, UPMC/ENS/CNRS, 24, rue Lhomond, 75231 Paris Cedex 05 (France);2. Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, 75005, Paris (France);3. école Normale Supérieure—PSL Research University, Département de Chimie, 24, rue Lhomond, 75005 Paris (France);4. Institut Curie, 91405 Orsay (France);5. INSERM U759, 91405 Orsay (France);6. School of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ (United Kingdom);7. Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Collège de France UMR 7574, Chimie de la Matière Condensée de Paris, 75005, Paris (France);8. Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochime (BCH), 1015 Lausanne (Switzerland) |
| Abstract: | Deuterium (2H) magic‐angle spinning (MAS) nuclear magnetic resonance is applied to monitor the dynamics of the exchanging labile deuterons of polycrystalline L ‐histidine hydrochloride monohydrate‐d7 and α‐oxalic acid dihydrate‐d6. Direct experimental evidence of fast dynamics is obtained from T1Z and T1Q measurements. Further motional information is extracted from two‐dimensional single‐quantum (SQ) and double‐quantum (DQ) MAS spectra. Differences between the SQ and DQ linewidths clearly indicate the presence of motions on intermediate timescales for the carboxylic moiety and the D2O in α‐oxalic acid dihydrate, and for the amine group and the D2O in L ‐histidine hydrochloride monohydrate. Comparison of the relaxation rate constants of Zeeman and quadrupolar order with the relaxation rate constants of the DQ coherences suggests the co‐existence of fast and slow motional processes. |
| Keywords: | deuterium magic‐angle spinning molecular dynamics NMR spectroscopy solid‐state structures |