Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Raman spectra of crystalline secondary amides. / Kolesov, Boris A.
в: Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy, Том 179, 15.05.2017, стр. 216-220.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Raman spectra of crystalline secondary amides
AU - Kolesov, Boris A.
N1 - Copyright © 2017 Elsevier B.V. All rights reserved.
PY - 2017/5/15
Y1 - 2017/5/15
N2 - We present a Raman-spectroscopic study of secondary amides (acetanilide, methacetin, phenacetine, orthorhombic and monoclinic polymorphs of paracetamol) as well as simple amides formanilide and benzanilide. The study was carried out on single crystals and in the temperature range of 5–300 K. The series of compounds with the same molecular fragment - acetamide group – can serve as a model system to study the interrelation between this group and the properties of the intermolecular “peptide-type” NH ⋯ O[dbnd]C hydrogen bonds. For all of the “acetamide family” of the compounds, similar changes in the Raman spectra were observed upon cooling of the samples: emergence of new Amide I(−) and Amide I(+) bands, which are red and blue shifted, respectively, from the conventional Amide-I band by around of 5–10 cm− 1. Corresponding changes in the same temperature range were observed for the N[sbnd]H out-of-plane bending (Amide V) and N[sbnd]H stretching vibrations of the N[sbnd]H ⋯ O[dbnd]C hydrogen bond. All of the spectral changes observed upon cooling of the samples can be presumed to result from a delocalization of the Amide-I and N[sbnd]H modes and appearance of dynamical (Davydov's) splitting at low temperature.
AB - We present a Raman-spectroscopic study of secondary amides (acetanilide, methacetin, phenacetine, orthorhombic and monoclinic polymorphs of paracetamol) as well as simple amides formanilide and benzanilide. The study was carried out on single crystals and in the temperature range of 5–300 K. The series of compounds with the same molecular fragment - acetamide group – can serve as a model system to study the interrelation between this group and the properties of the intermolecular “peptide-type” NH ⋯ O[dbnd]C hydrogen bonds. For all of the “acetamide family” of the compounds, similar changes in the Raman spectra were observed upon cooling of the samples: emergence of new Amide I(−) and Amide I(+) bands, which are red and blue shifted, respectively, from the conventional Amide-I band by around of 5–10 cm− 1. Corresponding changes in the same temperature range were observed for the N[sbnd]H out-of-plane bending (Amide V) and N[sbnd]H stretching vibrations of the N[sbnd]H ⋯ O[dbnd]C hydrogen bond. All of the spectral changes observed upon cooling of the samples can be presumed to result from a delocalization of the Amide-I and N[sbnd]H modes and appearance of dynamical (Davydov's) splitting at low temperature.
KW - Dynamical splitting
KW - Hydrogen bonds
KW - Molecular crystals
KW - Raman spectra
KW - Secondary amides
KW - SOLITONS
KW - NEUTRON-DIFFRACTION
KW - VARIABLE-TEMPERATURE
KW - PARACETAMOL P-HYDROXYACETANILIDE
KW - ACETANILIDE
UR - http://www.scopus.com/inward/record.url?scp=85013746628&partnerID=8YFLogxK
U2 - 10.1016/j.saa.2017.02.046
DO - 10.1016/j.saa.2017.02.046
M3 - Article
C2 - 28249236
AN - SCOPUS:85013746628
VL - 179
SP - 216
EP - 220
JO - Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
JF - Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
SN - 1386-1425
ER -
ID: 10303909