Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Electron spin echo envelope modulation of molecular motions of deuterium nuclei. / Syryamina, V. N.; Maryasov, A. G.; Bowman, M. K. и др.
в: Journal of Magnetic Resonance, Том 261, 01.12.2015, стр. 169-174.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Electron spin echo envelope modulation of molecular motions of deuterium nuclei
AU - Syryamina, V. N.
AU - Maryasov, A. G.
AU - Bowman, M. K.
AU - Dzuba, S. A.
PY - 2015/12/1
Y1 - 2015/12/1
N2 - Electron Spin Echo Envelope Modulation (ESEEM) spectroscopy is a powerful technique for the study of hyperfine interactions between an unpaired electron and nearby nuclei in solids, and is employed in quantitative structural studies. Here, we describe the use of ESEEM to study the slow motion of deuterium nuclei using their nuclear quadrupole resonance (NQR) line shapes. Two ESEEM techniques were employed: the conventional three-pulse ESEEM experiment, π/2 - τ - π/2 - T- π/2 - τ - echo, and the four-pulse ESEEM, π/2 - τ - π/2 - T/2 - π - T/2 - π/2 - τ - echo, with the time variable T scanned in both cases. The nitroxide free radical 4-tert-butyliminomethyl-2,2,5,5-tetramethyl(d12)-3-imidazoline-1-oxyl with four deuterated methyl groups was investigated in a glassy ortho-terphenyl matrix over a wide temperature range. It was shown that four-pulse ESEEM allowed measurement of the nearly pure 2H NQR line shape. Between 90 K and 120 K, the ESEEM spectra change drastically. At low temperatures, four-pulse ESEEM spectra show a Pake-like pattern, which evolves into a single line at higher temperatures, which is typical for NQR of rotating methyl CD3 groups. Comparison with literature data on NQR allows estimation of the reorientation rate, k. At ∼100 K, where the spectral changes are most pronounced, k was found to be ∼105 s-1. The spectral linewidths for the three-pulse ESEEM were found to decrease similarly with increasing temperature; so the three-pulse technique is also capable to detect motion of this type. The ESEEM approach, along with site-directed spin labeling, may be useful for detection of motional transitions near the spin labels in biological systems, when information on motion is required in a wide temperature range.
AB - Electron Spin Echo Envelope Modulation (ESEEM) spectroscopy is a powerful technique for the study of hyperfine interactions between an unpaired electron and nearby nuclei in solids, and is employed in quantitative structural studies. Here, we describe the use of ESEEM to study the slow motion of deuterium nuclei using their nuclear quadrupole resonance (NQR) line shapes. Two ESEEM techniques were employed: the conventional three-pulse ESEEM experiment, π/2 - τ - π/2 - T- π/2 - τ - echo, and the four-pulse ESEEM, π/2 - τ - π/2 - T/2 - π - T/2 - π/2 - τ - echo, with the time variable T scanned in both cases. The nitroxide free radical 4-tert-butyliminomethyl-2,2,5,5-tetramethyl(d12)-3-imidazoline-1-oxyl with four deuterated methyl groups was investigated in a glassy ortho-terphenyl matrix over a wide temperature range. It was shown that four-pulse ESEEM allowed measurement of the nearly pure 2H NQR line shape. Between 90 K and 120 K, the ESEEM spectra change drastically. At low temperatures, four-pulse ESEEM spectra show a Pake-like pattern, which evolves into a single line at higher temperatures, which is typical for NQR of rotating methyl CD3 groups. Comparison with literature data on NQR allows estimation of the reorientation rate, k. At ∼100 K, where the spectral changes are most pronounced, k was found to be ∼105 s-1. The spectral linewidths for the three-pulse ESEEM were found to decrease similarly with increasing temperature; so the three-pulse technique is also capable to detect motion of this type. The ESEEM approach, along with site-directed spin labeling, may be useful for detection of motional transitions near the spin labels in biological systems, when information on motion is required in a wide temperature range.
KW - H NQR
KW - ESEEM
KW - Molecular motions
KW - Solvation shell
KW - Spin label
UR - http://www.scopus.com/inward/record.url?scp=84947067571&partnerID=8YFLogxK
U2 - 10.1016/j.jmr.2015.10.005
DO - 10.1016/j.jmr.2015.10.005
M3 - Article
C2 - 26583529
AN - SCOPUS:84947067571
VL - 261
SP - 169
EP - 174
JO - Journal of Magnetic Resonance
JF - Journal of Magnetic Resonance
SN - 1090-7807
ER -
ID: 25831700