Structural isotopic effects in the smallest chiral amino acid: observation of a structural phase transition in fully deuterated alanine.
J Phys Chem B
; 111(19): 5034-9, 2007 May 17.
Article
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| MEDLINE
| ID: mdl-17439273
ABSTRACT
A first study of possible changes instigated by deuteration in amino acids was carried out using neutron diffraction, inelastic neutron scattering, and Raman scattering in l-alanine, C2H4(NH2)COOH. Careful analysis of the structural parameters shows that deuteration of l-alanine engenders significant geometric changes as a function of temperature, which can be directly related to the observation of new lattice vibration modes in the Raman spectra. The combination of the experimental data suggests that C2D4(ND2)COOD undergoes a structural phase transition (or a structural rearrangement) at about 170 K. Considering that this particular amino acid is a hydrogen-bonded system with short hydrogen bonds (O...H approximately 1.8 A), we evoke the Ubbelohde effect to conclude that substitution of hydrogen for deuterium gives rise to changes in the hydrogen-bonding interactions. The structural differences suggest distinct relative stabilities for the hydrogenous and deuterated l-alanine.
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Banco de datos:
MEDLINE
Asunto principal:
Alanina
Idioma:
En
Año:
2007
Tipo del documento:
Article