What Are the Relative Intensities of the Components of NMR Spectral Multiplets from Quadrupolar Nuclei in Uniformly Anisotropic Media?

Elliott, Stuart J.; Kuchel, Philip W.

doi:10.1155/2021/8890478

Cited by 3 publications

(1 citation statement)

References 37 publications

(80 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“… 4 The use of uniformly stretched hydrogels in NMR experiments has led to several informative applications: ( i ) quantification of 13 C-labeled isotopomers and isotopologues in mixtures; ( ii ) discrimination of enantiomers in chiral molecules; ( iii ) molecular structure refinement; and ( iv ) analysis of molecular mobility. 5 …”

Section: Introductionmentioning

confidence: 99%

Multiple quantum filtered nuclear magnetic resonance of 23Na+ in uniformly stretched and compressed hydrogels

Elliott

Eykyn

Kuchel

2023

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Stretching or compressing hydrogels creates anisotropic environments that lead to motionally averaged alignment of embedded guest quadrupolar nuclear spins such as 23Na+. These distorted hydrogels can elicit a residual quadrupolar coupling that gives an oscillation in the trajectories of single quantum coherences (SQCs) as a function of the evolution time during a spin-echo experiment. We present solutions to equations of motion derived with a Liouvillian superoperator approach, which encompass the coherent quadrupolar interaction in conjunction with relaxation, to give a full analytical description of the evolution trajectories of rank-1 (T^1±1), rank-2 (T^2±1), and rank-3 (T^3±1) SQCs. We performed simultaneous numerical fitting of the experimental 23Na nuclear magnetic resonance (NMR) spectra and rank-2 (T^2±1) and rank-3 (T^3±1) SQC evolution trajectories measured in double and triple quantum filtered experiments, respectively. We estimated values of the quadrupolar coupling constant CQ, rotational correlation time τC, and 3 × 3 Saupe order matrix. We performed simultaneous fitting of the analytical expressions to the experimental data to estimate values of the quadrupolar coupling frequency ωQ/2π, residual quadrupolar coupling ωQ/2π, and corresponding spherical order parameter S0*, which showed a linear dependence on the extent of uniform hydrogel stretching and compression. The analytical expressions were completely concordant with the numerical approach. The insights gained here can be extended to more complicated (biological) systems such as 23Na+ bound to proteins or located inside and outside living cells in high-field NMR experiments and, by extension, to the anisotropic environments found in vivo with 23Na magnetic resonance imaging.

show abstract

Section: Introductionmentioning

confidence: 99%

Multiple quantum filtered nuclear magnetic resonance of 23Na+ in uniformly stretched and compressed hydrogels

Elliott

Eykyn

Kuchel

2023

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

show abstract

Multinuclear Residual Quadrupolar Couplings for Structure and Assignment

John,

Rüttger

2024

ChemPhysChem

View full text Add to dashboard Cite

Most stable isotopes have a nuclear spin > 1/2, but the quadrupole interaction poses challenge on their detection by nuclear magnetic resonance (NMR). On the other hand, the quadrupole interaction is a rich source of structural information that may be exploited for solution NMR in the form of residual quadrupolar couplings (RQCs) of weakly oriented samples. While 2H RQCs are now well established for structure verification and enantiomeric discrimination of organic molecules, we will in this article highlight some recent work on RQCs of other nuclei (especially 7Li and 11B).

show abstract

Stretch‐Induced Ordering of Prochiral Dimethyl Sulfoxide in Anisotropic Hydrogels Analysed by ¹H and ²H Nuclear Magnetic Resonance

Elliott,

Kuchel,

Eykyn

2024

ChemPhysChem

View full text Add to dashboard Cite

Nuclear spins in small molecules dissolved in stretched hydrogels typically have population‐averaged residual interactions. The nuclear magnetic resonance (NMR) spectra of these systems often show additional peaks and splittings compared with free solutions. Residual dipolar couplings (RDCs) and quadrupolar couplings (RQCs) are observed for guest 1H or 2H nuclear spins, respectively. Dimethyl sulfoxide (DMSO) is an exquisitely sensitive probe of such biologically relevant environments since it is prochiral and becomes effectively chiral when embedded in anisotropic gelatin‐based hydrogels. Measured 1H RDCs and 2H RQCs were used to estimate bond order parameters over a wide range of stretching extents. At the largest extent of stretching, the 2H splittings were ‐73.0 and ‐9.4 Hz, similar to those found for guest molecules in liquid crystals. Inhomogeneous line broadening of the 2H resonances was related to the size of the RQC due to a spatial distribution of RQCs, which was revealed using a one‐dimensional slice selective imaging experiment along the stretching direction. 1H NMR spectra exhibited homogeneous line broadening, with resonance integrals that indicated concealed multiplet structure. Understanding molecular bond ordering in mechanically oriented environments provides a conceptual framework for investigating more complex systems including zeolites and those found in vivo.

show abstract

What Are the Relative Intensities of the Components of NMR Spectral Multiplets from Quadrupolar Nuclei in Uniformly Anisotropic Media?

Cited by 3 publications

References 37 publications

Multiple quantum filtered nuclear magnetic resonance of 23Na+ in uniformly stretched and compressed hydrogels

Multiple quantum filtered nuclear magnetic resonance of 23Na+ in uniformly stretched and compressed hydrogels

Multinuclear Residual Quadrupolar Couplings for Structure and Assignment

Stretch‐Induced Ordering of Prochiral Dimethyl Sulfoxide in Anisotropic Hydrogels Analysed by ¹H and ²H Nuclear Magnetic Resonance

Contact Info

Product

Resources

About

What Are the Relative Intensities of the Components of NMR Spectral Multiplets from Quadrupolar Nuclei in Uniformly Anisotropic Media?

Cited by 3 publications

References 37 publications

Multiple quantum filtered nuclear magnetic resonance of 23Na+ in uniformly stretched and compressed hydrogels

Multiple quantum filtered nuclear magnetic resonance of 23Na+ in uniformly stretched and compressed hydrogels

Multinuclear Residual Quadrupolar Couplings for Structure and Assignment

Stretch‐Induced Ordering of Prochiral Dimethyl Sulfoxide in Anisotropic Hydrogels Analysed by 1H and 2H Nuclear Magnetic Resonance

Contact Info

Product

Resources

About

Stretch‐Induced Ordering of Prochiral Dimethyl Sulfoxide in Anisotropic Hydrogels Analysed by ¹H and ²H Nuclear Magnetic Resonance