Determination of Molecular Torsion Angles Using Nuclear Singlet Relaxation

Tayler, Michael C. D.; Marie, Sabrina; Ganesan, A.; Levitt, Malcolm H.

doi:10.1021/ja1012917

Cited by 40 publications

(34 citation statements)

References 15 publications

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“…This relaxation mechanism was modeled at high magnetic field by Tayler et al [21], who derived an expression for the enhancement of the singlet lifetime * : Here spins 1 and 2 compose the singlet while j represents another nearby spin;…”

Section: Singlet Relaxation Mechanismsmentioning

confidence: 99%

Dependence of nuclear spin singlet lifetimes on RF spin-locking power

DeVience

Walsworth

Rosen

2012

Journal of Magnetic Resonance

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We measure the lifetime of long-lived nuclear spin singlet states as a function of the strength of the RF spin-locking field and present a simple theoretical model that agrees well with our measurements, including the low-RF-power regime. We also measure the lifetime of a long-lived coherence between singlet and triplet states that does not require a spin-locking field for preservation. Our results indicate that for many molecules, singlet states can be created using weak RF spin-locking fields: more than two orders of magnitude lower RF power than in previous studies. Our findings suggest that in many biomolecules, singlets and related states with enhanced lifetimes might be achievable in vivo with safe levels of RF power.

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Section: Singlet Relaxation Mechanismsmentioning

confidence: 99%

Dependence of nuclear spin singlet lifetimes on RF spin-locking power

DeVience

Walsworth

Rosen

2012

Journal of Magnetic Resonance

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“…S [iDD] modelling options, we have first the assumption of a rigid molecule conformation and a single exponential TCF 17,19,20,83 . A characteristic correlation time for this hypothesis may in a realistic way be extracted from MD simulation from the TCF for molecules I and II from the TCF of the j-k vector, where intramolecular dynamics only have a minor influence.…”

Section: −1mentioning

confidence: 99%

“…In cases of rigid molecular geometry, standard techniques based on Abragam-Redfield relaxation theory may be used to analyze nuclear dipole-dipole (DD) interactions and to predict molecular geometries that support LLS with long lifetimes [17][18][19][20] . In strong magnetic fields, chemical shift anisotropy (CSA) often dominates the relaxation of nuclear singlet order.…”

Section: Introductionmentioning

confidence: 99%

Prediction of low-field nuclear singlet lifetimes with molecular dynamics and quantum-chemical property surface

Håkansson

2017

Phys. Chem. Chem. Phys.

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Molecular dynamics and quantum chemistry methods are implemented to quantify nuclear spin-1/2 pair singlet-state relaxation rates for three molecular systems at low magnetic field and room temperature. Computational methodology is developed for weak interactions, particularly important for singlet states at low field. These include spin-rotation and spin-internal-motion effects, which describe the coupling of the spin-carrying nuclei to fluctuating local magnetic fields induced by the overall and internal molecular fluctuations, respectively. A high-dimensional tensor property surface using Kriging interpolation is developed to circumvent costly quantum-chemical calculations. Together with the intramolecular dipolar relaxation, all the simulated relaxation mechanisms are accounted for with a common theoretical framework. Comparison with experiment indicates that quantitative accuracy is obtained, sufficient to enable guidance in the molecular design of molecules with long-lived singlet order.

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“…The population imbalance between the singlet state and the triplet states is called singlet order and is protected against many common relaxation mechanisms [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The relaxation time constant for singlet order is called T S and often exceeds the conventional longitudinal relaxation time T 1 by a large factor [16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Long-lived nuclear spin states in rapidly rotating CH 2 D groups

Elliott

Brown

Dumez

et al. 2016

Journal of Magnetic Resonance

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Although monodeuterated methyl groups support proton long-lived states, hindering of the methyl rotation limits the singlet relaxation time. We demonstrate an experimental case in which the rapid rotation of the CH 2 D group extends the singlet lifetime but does not quench the chemical shift difference between the CH 2 D protons, induced by the chiral environment. Proton singlet order is accessed using Spin-Lock Induced Crossing (SLIC) experiments, showing that the singlet relaxation time T S is over 2 minutes, exceeding the longitudinal relaxation time T 1 by a factor of more than 10. This result shows that proton singlet states may be accessible and long-lived in rapidly rotating CH 2 D groups.

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Determination of Molecular Torsion Angles Using Nuclear Singlet Relaxation

Cited by 40 publications

References 15 publications

Dependence of nuclear spin singlet lifetimes on RF spin-locking power

Dependence of nuclear spin singlet lifetimes on RF spin-locking power

Prediction of low-field nuclear singlet lifetimes with molecular dynamics and quantum-chemical property surface

Long-lived nuclear spin states in rapidly rotating CH 2 D groups

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