Improved sensitivity and quantification for 29Si NMR experiments on solids using UDEFT (Uniform Driven Equilibrium Fourier Transform)

Duong, Nghia Tuan; Trébosc, Julien; Lafon, Olivier; Amoureux, Jean‐Paul

doi:10.1016/j.ssnmr.2019.03.007

Cited by 10 publications

(5 citation statements)

References 92 publications

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“…The third approach is to apply pulse sequences based on refocusing effect such as Carr-Purcell-Meiboom-Gill (CPMG) echo-train acquisition [44,45] or Uniform Driven Equilibrium Fourier Transform (UDEFT) sequence with composite pulses [46,47] ). These pulse sequences are used for nuclei with long relaxation times.…”

Section: Approaches For Sensitivity Enhancementmentioning

confidence: 99%

See 1 more Smart Citation

Application of Multinuclear MAS NMR for the in situ Monitoring of Hydrothermal Synthesis of Zeolites

Иванова

Kolyagin

2021

Chemistry A European J

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Section: Approaches For Sensitivity Enhancementmentioning

confidence: 99%

“…In theory, the application of these approaches can give a 10-fold increase in sensitivity. [44,47] We have not found any reports on the application of CPMG or UDEFT for in situ NMR studies of zeolite synthesis, but it appears that nothing prevents doing this in the future.…”

Section: Approaches For Sensitivity Enhancementmentioning

confidence: 99%

Application of Multinuclear MAS NMR for the in situ Monitoring of Hydrothermal Synthesis of Zeolites

Иванова

Kolyagin

2021

Chemistry A European J

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“…S1. According to the literature, the 27 AlO 4 signal subsumes the resonances of two AlO 4 sites with quadrupolar coupling constants C Q = 1.7 and 4.1 MHz, whereas those of AlO 5 and AlO 6 sites are equal to 5.6 and 2.6 MHz, respectively (Fernandez et al, 1996;Antonijevic et al, 2006). The 1 H-1 H dipolar couplings within the isopropylamine template molecule are larger than in γ -alumina.…”

Section: Alpo 4 -14mentioning

confidence: 99%

Improved NMR transfer of magnetization from protons to half-integer spin quadrupolar nuclei at moderate and high magic-angle spinning frequencies

Gómez¹,

Rankin²,

Trébosc

et al. 2021

Magn. Reson.

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Abstract. Half-integer spin quadrupolar nuclei are the only magnetic isotopes for the majority of the chemical elements. Therefore, the transfer of polarization from protons to these isotopes under magic-angle spinning (MAS) can provide precious insights into the interatomic proximities in hydrogen-containing solids, including organic, hybrid, nanostructured and biological solids. This transfer has recently been combined with dynamic nuclear polarization (DNP) in order to enhance the NMR signal of half-integer quadrupolar isotopes. However, the cross-polarization transfer lacks robustness in the case of quadrupolar nuclei, and we have recently introduced as an alternative technique a D-RINEPT (through-space refocused insensitive nuclei enhancement by polarization transfer) scheme combining a heteronuclear dipolar recoupling built from adiabatic pulses and a continuous-wave decoupling. This technique has been demonstrated at 9.4 T with moderate MAS frequencies, νR≈10–15 kHz, in order to transfer the DNP-enhanced 1H polarization to quadrupolar nuclei. Nevertheless, polarization transfers from protons to quadrupolar nuclei are also required at higher MAS frequencies in order to improve the 1H resolution. We investigate here how this transfer can be achieved at νR≈20 and 60 kHz. We demonstrate that the D-RINEPT sequence using adiabatic pulses still produces efficient and robust transfers but requires large radio-frequency (rf) fields, which may not be compatible with the specifications of most MAS probes. As an alternative, we introduce robust and efficient variants of the D-RINEPT and PRESTO (phase-shifted recoupling effects a smooth transfer of order) sequences using symmetry-based recoupling schemes built from single and composite π pulses. Their performances are compared using the average Hamiltonian theory and experiments at B0=18.8 T on γ-alumina and isopropylamine-templated microporous aluminophosphate (AlPO4-14), featuring low and significant 1H–1H dipolar interactions, respectively. These experiments demonstrate that the 1H magnetization can be efficiently transferred to 27Al nuclei using D-RINEPT with SR412(270090180) recoupling and using PRESTO with R2227(1800) or R1676(270090180) schemes at νR=20 or 62.5 kHz, respectively. The D-RINEPT and PRESTO recoupling schemes complement each other since the latter is affected by dipolar truncation, whereas the former is not. We also analyze the losses during these recoupling schemes, and we show how these magnetization transfers can be used at νR=62.5 kHz to acquire in 72 min 2D HETCOR (heteronuclear correlation) spectra between 1H and quadrupolar nuclei, with a non-uniform sampling (NUS).

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“…(Giovine et al, 2019a) We screened here the R  schemes built from single rectangular and composite π-pulses to achieve γ-encoded of quadrupolar nuclei with high-resolution 1 H spectra without using homo-nuclear dipolar decoupling. We tested the following composite π-pulses: 270090180 with ξ tot /(2π) = 2, which is offset-compensated and amplitude modulated and has been employed in several R  sequences, (Giovine et al, 2019a;Carravetta et al, 2000;Levitt, 2002;Pandey et al, 2015) 90024090900 with ξ tot /(2π) = 7/3, which compensates both rf inhomogeneity and offset, (Freeman et al, 1980;Duong et al, 2019) and 90−45904590−45 with ξ tot /(2π) = 3/2, which has homo-nuclear decoupling properties. (Madhu et al, 2001) Adiabatic pulses cannot be employed for SQ hetero-nuclear dipolar recoupling since they yield vanishing scaling factors for the rotational components with μ ≠ 0.…”

Section: Ii-1-2 Selection Of the Recoupling Sequencementioning

confidence: 99%

Comment on mr-2021-29

2021

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Half-integer spin quadrupolar nuclei are the only magnetic isotopes for the majority of the chemical elements.Therefore, the transfer of polarization from protons to these isotopes under magic-angle spinning (MAS) can provide precious insights into the interatomic proximities in hydrogen-containing solids, including organic, hybrid, nanostructured and biological solids. Furthermore, this transfer has recently been combined with dynamic nuclear polarization (DNP) in order to enhance the NMR signal of half-integer quadrupolar isotope. Nevertheless, the cross-polarization transfer lacks of robustness in the case of quadrupolar nuclei and we have recently introduced as an alternative technique a through-space refocused insensitive nuclei enhancement by polarization transfer (D-RINEPT) scheme combining hetero-nuclear dipolar recoupling built from adiabatic pulses and continuous wave decoupling. This technique has been demonstrated at 9.4 T with moderate MAS frequencies, νR  10-15 kHz, in order to transfer the DNP-enhanced 1 H polarization to quadrupolar nuclei. Nevertheless, polarization transfers from protons to quadrupolar nuclei are also required at higher MAS frequencies in order to improve the resolution of 1 H spectra. We investigate how this transfer can be achieved at νR  20 and 60 kHz. We demonstrate that the D-RINEPT sequence using adiabatic pulses still produces efficient and robust transfer but requires large rf-fields, which may not be compatible with the specifications of commonly employed MAS NMR probes. As an alternative, we introduce robust and efficient variants of D-RINEPT and PRESTO (phase-shifted recoupling effects a smooth transfer of order) sequences using symmetry-based recoupling schemes built from single and composite π-pulses. Their performances are compared using the

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Improved sensitivity and quantification for 29Si NMR experiments on solids using UDEFT (Uniform Driven Equilibrium Fourier Transform)

Cited by 10 publications

References 92 publications

Application of Multinuclear MAS NMR for the in situ Monitoring of Hydrothermal Synthesis of Zeolites

Application of Multinuclear MAS NMR for the in situ Monitoring of Hydrothermal Synthesis of Zeolites

Improved NMR transfer of magnetization from protons to half-integer spin quadrupolar nuclei at moderate and high magic-angle spinning frequencies

Comment on mr-2021-29

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