ChemInform Abstract: 13C NMR Relaxation and Molecular Dynamics. Overall Movement and Internal Rotation of Methyl Groups in N,N-Dimethylformamide.

ChemInform ◽  
1990 ◽  
Vol 21 (23) ◽  
Author(s):  
R. KONRAT ◽  
H. STERK
Keyword(s):  
Molecular Dynamics ◽  
Internal Rotation ◽  
13C Nmr ◽  
Nmr Relaxation ◽  
Methyl Groups

scholarly journals Flexibility at a glycosidic linkage revealed by molecular dynamics, stochastic modeling, and 13C NMR spin relaxation: conformational preferences of α-l-Rhap-α-(1 → 2)-α-l-Rhap-OMe in water and dimethyl sulfoxide solutions

2016 ◽  
Vol 18 (4) ◽  
pp. 3086-3096 ◽  
Author(s):  
Robert Pendrill ◽  
Olof Engström ◽  
Andrea Volpato ◽  
Mirco Zerbetto ◽  
Antonino Polimeno ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Stochastic Modeling ◽  
Spin Relaxation ◽  
13C Nmr ◽  
Nmr Relaxation ◽  
Glycosidic Linkage ◽  
Local Motion ◽  
Flexible Molecule ◽  
Relaxation Parameters ◽  
Conformational Preferences

Coupling between global reorientation and local motion is essential for reproducing NMR relaxation parameters of a flexible molecule.

Structure and Dynamics of Spherical and Rodlike Alkyl Ethoxylate Surfactant Micelles Investigated Using NMR Relaxation and Atomistic Molecular Dynamics Simulations

2019 ◽  
Author(s):  
Allison Edwards ◽  
Abdolreza Javidialesaadi ◽  
Katie Weigandt ◽  
George Stan ◽  
Charles Eads
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Nmr Relaxation ◽  
Cross Relaxation ◽  
Relaxation Rates ◽  
Surfactant Micelles ◽  
Cylindrical Micelles ◽  
Spherical Micelles ◽  
Dynamics Simulations ◽  
Relative Motions

We study molecular arrangements and dynamics in alkyl ethoxylate nonionic surfactant micelles by combining high field (600 and 700 MHz) NMR relaxation measurements with large-scale atomistic molecular dynamics simulations. For spherical micelles, but not for cylindrical micelles, cross relaxation rates are positive only for surfactant alkyl tail atoms connected to the hydrophilic head group. All cross relaxation rates are negative for cylindrical micelles. This effect is reproducible either by changing composition (ratios of the nonionic surfactants) or changing temperature of a single surfactant in order to change the micelle shape. We validate the micelle shape by SANS and use the results as a guide for our simulations. We calculate parameters that determine relaxation rates directly from simulated trajectories, without introducing specific functional forms. Results indicate that relative motions of nearby atoms are liquid-like, in agreement with 13C T1 measurements, though constrained by micelle morphology. Relative motions of distant atoms have slower components because the relative changes in distances and angles are smaller when the moving atoms are further apart. The slow, long-range motions appear to be responsible for the predominantly negative cross relaxation rates observed in NOESY spectra. The densities of atoms from positions 1 and 2 in the boundary region are lower in spherical micelles compared to cylindrical micelles. Correspondingly, motions in this region are less constrained by micelle morphology in the spherical compared to the cylindrical cases. The two effects of morphology lead to the unusual occurrence of positive cross relaxation involving positions 1 and 2 for spheres.

scholarly journals Unveiling the Interplay Between Diffusing CO2 and Ethanol Molecules in Champagne Wines by Classical Molecular Dynamics and 13C NMR Spectroscopy

2014 ◽  
Vol 5 (24) ◽  
pp. 4232-4237 ◽  
Author(s):  
David A. Bonhommeau ◽  
Alexandre Perret ◽  
Jean-Marc Nuzillard ◽  
Clara Cilindre ◽  
Thibaud Cours ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Classical Molecular Dynamics
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