TY - JOUR
T1 - Structural isotopic effects in the smallest chiral amino acid
T2 - Observation of a structural phase transition in fully deuterated alanine
AU - De Souza, Joelma M.
AU - Freire, Paulo T.C.
AU - Bordallo, Heloisa N.
AU - Argyriou, Dimitri N.
PY - 2007/5/17
Y1 - 2007/5/17
N2 - 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 C2(ND4)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 ∼ 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.
AB - 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 C2(ND4)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 ∼ 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.
UR - http://www.scopus.com/inward/record.url?scp=34249776093&partnerID=8YFLogxK
U2 - 10.1021/jp070366z
DO - 10.1021/jp070366z
M3 - Journal article
AN - SCOPUS:34249776093
SN - 1520-6106
VL - 111
SP - 5034
EP - 5039
JO - Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical
JF - Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical
IS - 19
ER -