Anisotropic rotational diffusion and intramolecular motion in cyclic amino acids and peptides. An interpretation of carbon-13 spin-lattice relaxation data

1976 ◽  
Vol 98 (21) ◽  
pp. 6460-6467 ◽  
Author(s):  
R. L. Somorjai ◽  
Roxanne Deslauriers
Keyword(s):  
Amino Acids ◽  
Rotational Diffusion ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Relaxation Data ◽  
Spin Lattice ◽  
Intramolecular Motion ◽  
Anisotropic Rotational Diffusion ◽  
Cyclic Amino Acids

Fourier transform carbon-13 spin–lattice relaxation study of motion of cyclic hydrocarbons

1980 ◽  
Vol 58 (16) ◽  
pp. 1679-1686 ◽  
Author(s):  
David E. Axelson ◽  
Clive E. Holloway
Keyword(s):  
Fourier Transform ◽  
Structural Information ◽  
Rotational Diffusion ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Diffusion Constants ◽  
Relaxation Experiments ◽  
Resonance Spin ◽  
Anisotropic Rotational Diffusion

The molecular dynamics in solution for a series of cyclic and bicyclic hydrocarbon derivatives has been investigated by C-13 pulsed Fourier Transform nuclear magnetic resonance spin–lattice relaxation experiments. Molecular motion has been analysed in terms of an anisotropic rotational diffusion model, and an attempt has been made to assess the effects of structure on the observed rotational diffusion constants. Errors in the diffusion constants are discussed, and some of the other problems inherent in the use of these parameters to obtain structural information are outlined.

Anion reorientations and cation diffusion in a carbon-substituted sodium nido-borate Na-7,9-C2B9H12: 1H and 23Na NMR studies

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexander V. Skripov ◽  
Olga A. Babanova ◽  
Roman V. Skoryunov ◽  
Alexei V. Soloninin ◽  
Terrence J. Udovic
Keyword(s):  
Lattice Relaxation ◽  
Activation Energies ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Cation Diffusion ◽  
Relaxation Data ◽  
Nmr Studies ◽  
Spin Lattice ◽  
Jump Rate ◽  
Disordered Phase

Abstract Polyhydroborate-based salts of lithium and sodium have attracted much recent interest as promising solid-state electrolytes for energy-related applications. A member of this family, sodium dicarba-nido-undecahydroborate Na-7,9-C2B9H12 exhibits superionic conductivity above its order-disorder phase transition temperature, ∼360 K. To investigate the dynamics of the anions and cations in this compound at the microscopic level, we have measured the 1H and 23Na nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates over the temperature range of 148–384 K. It has been found that the transition from the low-T ordered to the high-T disordered phase is accompanied by an abrupt, several-orders-of-magnitude acceleration of both the reorientational jump rate of the complex anions and the diffusive jump rate of Na+ cations. These results support the idea that reorientations of large [C2B9H12]− anions can facilitate cation diffusion and, thus, the ionic conductivity. The apparent activation energies for anion reorientations obtained from the 1H spin-lattice relaxation data are 314 meV for the ordered phase and 272 meV for the disordered phase. The activation energies for Na+ diffusive jumps derived from the 23Na spin-lattice relaxation data are 350 and 268 meV for the ordered and disordered phases, respectively.

scholarly journals A quantum mechanical alternative to the Arrhenius equation in the interpretation of proton spin–lattice relaxation data for the methyl groups in solids

2015 ◽  
Vol 17 (43) ◽  
pp. 28866-28878 ◽  
Author(s):  
Piotr Bernatowicz ◽  
Aleksander Shkurenko ◽  
Agnieszka Osior ◽  
Bohdan Kamieński ◽  
Sławomir Szymański
Keyword(s):  
Nmr Spectroscopy ◽  
Arrhenius Equation ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Quantum Mechanical ◽  
Methyl Groups ◽  
Relaxation Data ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation

The issue of nuclear spin–lattice relaxation in methyl groups in solids has been a recurring problem in NMR spectroscopy.

Relaxationszeiten des Elektronenspins von Radikalen in einigen bestrahlten Aminosäuren bei 4,2 °K

1966 ◽  
Vol 21 (3) ◽  
pp. 296-300 ◽  
Author(s):  
G. Bürk ◽  
G. Schoffa
Keyword(s):  
Amino Acids ◽  
Spin Relaxation ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Electron Spin Relaxation ◽  
Spin Lattice ◽  
Saturation Method ◽  
Rapid Adjustment ◽  
Inhomogeneous Line Broadening

Electron spin relaxation times of the irradiated amino acids acetyl valine, sarcosine, betaine, and glycine have been measured at 4.2 °K with two different methods. From the exponential decrease of signals due to saturation after rapid adjustment of the ESR spectrometer on resonance, the following spin-lattice relaxation times have been measured: acetyl valine T1= 0.2 sec, sarcosine T1=0.14 sec, betaine T1=0.07 sec, glycine T1 ∼ 0.3 sec. By the PORTIS saturation method the product T1 T2 was measured, and, T1 being known, the following spin-spin relaxation times T2 have been obtained: acetyl valine 2.1.10-9sec, sarcosine 1.10-9sec, betaine 9.10-10sec. All measured amino acids show the saturation behaviour of substances with “inhomogeneous” line broadening.

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