Yulan Wang, P. Belton, Huiru Tang
1997
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0
Influential Citations
6
Citations
Journal
Journal of The Chemical Society-perkin Transactions 1
Abstract
Crystalline L-leucinamide has been studied by 13C CP/MAS NMR, FTIR spectroscopy and X-ray crystallography. The 13C CP/MAS spectrum of crystalline L-leucinamide has been assigned using the depolarisation–repolarisation method. Two magnetically non-equivalent molecules in the unit cell have been found from the 13C CP/MAS spectra. Non-equivalence is also observed in the FTIR spectrum. The molecular dynamics were studied by measuring 13C spin–lattice relaxation in both laboratory and rotating frames. Results show that the mobilities of the two molecules are very different. Spin–lattice relaxation times for the two α carbons differ by an order of magnitude. Determination of the crystal structure by X-ray crystallography confirmed the existence of two distinct molecules in the unit cell; these differed in the orientation of the amide groups and in their involvement in the hydrogen bonding scheme, which may account for the observed NMR behaviour.