Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
<mark>Journal publication date</mark> | 12/01/2015 |
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<mark>Journal</mark> | ChemPhysChem |
Issue number | 1 |
Volume | 16 |
Number of pages | 12 |
Pages (from-to) | 204-215 |
Publication Status | Published |
Early online date | 30/10/14 |
<mark>Original language</mark> | English |
Deuterium (H-2) magic-angle spinning (MAS) nuclear magnetic resonance is applied to monitor the dynamics of the exchanging labile deuterons of polycrystalline L-histidine hydrochloride monohydrate-d(7) and -oxalic acid dihydrate-d(6). Direct experimental evidence of fast dynamics is obtained from T-1Z and T-1Q 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 -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.