Broadband adiabatic inversion cross-polarization phenomena in the NMR of rotating solids

Wi, Sungsool; Schurko, Robert W.; Frydman, Lucio

doi:10.1016/j.ssnmr.2018.08.003

Cited by 10 publications

(4 citation statements)

References 86 publications

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“…Bodenhausen, Amoureux, and co-workers reported a theoretical treatment describing the use of the DANTE pulse sequence for the acquisition of UWNMR spectra (examples for 19 F and 14 N were provided) . The use of the dipolar-HMQC (D-HMQC) pulse sequence (and several variants) for the acquisition of indirectly detected UWNMR spectra of both spin- 1 / 2 and quadrupolar nuclei have been explored by Amoureux et al , and Rossini et al − Finally, Wi et al have been carrying out studies featuring the use of BRAIN pulses for BCP to both spin- 1 / 2 and quadrupolar nuclei (applications for UWNMR have not yet been reported). − To date, there have been no reports of a reliable method for obtaining directly detected 1D UWNMR spectra of spin- 1 / 2 or quadrupolar nuclei using direct excitation (DE) or CP methods under MAS conditions, nor have there been any reports of implementations of CPMG-style sequences or frequency-swept pulses like WURST pulses for these purposes.…”

Section: Introductionmentioning

confidence: 99%

Practical Aspects of Recording Ultra-Wideline NMR Patterns under Magic-Angle Spinning Conditions

et al. 2020

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Many NMR-active nuclei give rise to solid-state NMR spectra that span extremely large frequency regions due to the effects of large anisotropic NMR interactions; such spectra, which can range from 250 kHz to several MHz in breadth, have been termed ultrawideline (UW) NMR spectra. UWNMR spectra are often too broad to be uniformly excited by conventional pulse sequences that implement rectangular radiofrequency (RF) pulses. Therefore, they are typically acquired with specialized pulse sequences and frequencyswept (FS) pulses; however, such experiments are conducted predominantly upon stationary samples (i.e., static NMR with no magic-angle spinning, MAS). Herein, we demonstrate how to implement Carr−Purcell Meiboom−Gill (CPMG) type pulse sequences that utilize rectangular pulses to acquire high-quality wideline and UWNMR spectra under MAS conditions, which are useful for providing uniformly excited patterns with substantial signal enhancements in comparison to conventional MAS NMR spectra and identifying peaks and/or patterns corresponding to magnetically nonequivalent sites. We discuss the pulse timings, delays, and the duration of windowed acquisition periods that are necessary for using CPMG-type pulse sequences for T 2 -dependent enhancement under MAS conditions while allowing for chemical shift resolution and maintaining a conventional spinning-sideband (SSB) manifold, as well as protocols for processing these spectra. Careful consideration is given to pulse lengths and RF amplitudes used in these pulse sequences. Using several spin-1 / 2 (i.e., 119 Sn, 207 Pb, 195 Pt) nuclei and one integer-spin quadrupolar nucleus (i.e., 2 H), we show how sensitivity-enhancing protocols, including CPMG and cross-polarization (CP), can be used to deliver high-quality MAS NMR spectra, which feature high signal-to-noise (S/N) ratios and uniformly excited SSB manifolds. The methods outlined herein are facile to implement and offer the potential to open up MAS NMR experiments to a wide variety of elements from across the periodic table.

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Section: Introductionmentioning

confidence: 99%

Practical Aspects of Recording Ultra-Wideline NMR Patterns under Magic-Angle Spinning Conditions

et al. 2020

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“…34 This journal is © the Owner Societies 2023 both static 42 and in combination with MAS have been reported. 43 Under the frequency sweep created by the WURST pulse on the dilute spin there will be points where the Hartmann-Hahn matching condition is fulfilled with the conventional spinlocking pulse applied to the abundant spin for each frequency element of the powder pattern. This has the advantages that there is a much lower power requirement on the X-spin side and the transfer efficiency is far less frequency offset dependent than for the conventional hard pulse CP experiment.…”

Section: Techniques For Sensitivity Enhancementmentioning

confidence: 99%

Recent progress in solid-state NMR of spin-½ low-γ nuclei applied to inorganic materials

Smith

2023

Phys. Chem. Chem. Phys.

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“…where ω Δ (t) = ω 1I -ω eS (t), ω Σ (t) = ω 1I + ω eS (t), and the single-transition operators for the zero-quantum (ZQ) and double-quantum (DQ) coherences are defined elsewhere. [33,40] Because only the ZQ CP mode is relevant for the static powder patterns and the single-transition operators defined in the ZQ and DQ subspaces commute with one another, the terms required for the CP process arẽ…”

Section: Adiabatic Inversions Of Integer Spins Under Static Conditionsmentioning

confidence: 99%

“…The BRAIN-CP pulse sequence has previously been implemented for 1 H- 14 N experiments [29] ; however, a theoretical description of the spin dynamics and HH matching conditions was not provided in the same detail as the static spin-1/2 case, [28] or for quadrupolar systems under magic-angle spinning (MAS). [32][33][34] We present an analytical derivation of the HH matching conditions during irradiation with an FS pulse, for CP from a spin-1/2 nucleus to an integer-spin nucleus, under static conditions. The spin dynamics and BRAIN-CP spin polarization transfer mechanisms are monitored using numerical simulations in conjunction with the analytical expressions.…”

Section: Introductionmentioning

confidence: 99%

Broadband adiabatic inversion cross‐polarization to integer‐spin nuclei with application to deuterium NMR

Altenhof

Schurko

2021

Magnetic Reson in Chemistry

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Solid-state NMR (SSNMR) spectroscopy of integer-spin quadrupolar nuclei is important for the molecular-level characterization of a variety of materials and biological solids; of the integer spins, 2 H (S = 1) is by far the most widely studied, due to its usefulness in probing dynamical motions. SSNMR spectra of integer-spin nuclei often feature very broad powder patterns that arise largely from the effects of the first-order quadrupolar interaction; as such, the acquisition of high-quality spectra continues to remain a challenge. The broadband adiabatic inversion cross-polarization (BRAIN-CP) pulse sequence, which is capable of cross-polarization (CP) enhancement over large bandwidths, has found success for the acquisition of SSNMR spectra of integer-spin nuclei, including 14 N (S = 1), especially when coupled with Carr-Purcell/Meiboom-Gill pulse sequences featuring frequency-swept WURST pulses (WURST-CPMG) for T 2 -based signal enhancement. However, to date, there has not been

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Broadband adiabatic inversion cross-polarization phenomena in the NMR of rotating solids

Cited by 10 publications

References 86 publications

Practical Aspects of Recording Ultra-Wideline NMR Patterns under Magic-Angle Spinning Conditions

Practical Aspects of Recording Ultra-Wideline NMR Patterns under Magic-Angle Spinning Conditions

Recent progress in solid-state NMR of spin-½ low-γ nuclei applied to inorganic materials

Broadband adiabatic inversion cross‐polarization to integer‐spin nuclei with application to deuterium NMR

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