Two-dimensional magic-angle spinning isotropic reconstruction sequences for quadrupolar nuclei

Massiot, Dominique; Touzo, Bruno; Trumeau, Dominique; Coutures, J.P.; Virlet, J.; Florian, Pierre; Grandinetti, Philip J.

doi:10.1016/0926-2040(95)01210-9

Cited by 430 publications

(527 citation statements)

References 14 publications

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“…In this case, the TQ coherences are directly converted into transverse magnetization by omitting the last 90° pulse of the reconversion sequence (figures 1b and 1d). This enables the acquisition of a full echo signal, as used in DAS [48] and MQMAS [49] experiments, which results in unambiguous phasing of the pure absorption mode 2D spectrum and improving the signal to noise ratio by up to a factor of 2 1/2 . The 31 P MAS spectrum of the (PbO) 0.61 (P 2 O 5 ) 0.39 glass (shown in Fig.…”

Section: Application To Phosphate Glassmentioning

confidence: 99%

Triple-quantum correlation NMR experiments in solids using J-couplings

Fayon

Roiland

Emsley

et al. 2006

Journal of Magnetic Resonance

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We show that triple-quantum -single-quantum (TQ-SQ) correlation spectra of crystalline and disordered solids can be obtained under MAS using pulse sequences based on through-bond J-couplings. The feasibility of the experiments in coupled spin-½ systems is demonstrated for fully 13 C-labelled L-alanine and Pb 3 P 4 O 13 crystalline compounds, considered as model three-spin and four-spin systems, respectively. In the case of phosphate glasses, we show that the obtained TQ-SQ correlation spectra provide an improved description of the glass forming network connectivities and of the chain length distribution in the disordered network. IntroductionHomonuclear double-quantum correlation spectroscopy has been shown to be a valuable tool in solid-state NMR for determining atomic connectivities and studying the structure and dynamic of ordered or disordered materials [1,2]. In this context, various experiments have been developed to obtain two-dimensional (2D) double-quantum -singlequantum (DQ-SQ) correlation spectra of coupled spin-½ systems under magic angle spinning (MAS) which is required for enhanced spectral resolution and sensitivity. Many of these methods employ pulse sequences which reintroduce the MAS-averaged through-space homonuclear dipolar interaction, to obtain DQ-SQ correlation spectra which reflect the through-space atomic proximities [3][4][5][6][7][8][9][10]. Alternatively, pulse sequences based on throughbond isotropic J-couplings, like the INADEQUATE [11] and refocused INADEQUATE [12] experiments, have also been applied efficiently to obtain through-bond DQ-SQ correlation spectra for large range of materials [12][13][14][15][16][17][18][19][20][21][22][23].In the case of inorganic glasses, for which the characterization of medium range order remains challenging, the DQ-SQ correlation experiment allows to improve the structural description obtained from NMR spectroscopy by determining the pairwise connectivities between the basic building units of the disordered network. In phosphate glasses, homonuclear through-bond [22,23] and through-space [24-25] DQ-SQ correlation methods have been applied successfully to probe P-O-P connectivities between the various network former PO 4 tetrahedral units (Q n with n bridging oxygen atoms). These experiments provide enhanced spectral resolution relative to the conventional MAS spectra allowing the distinction between Q n units bonded to different types of PO 4 to be made and giving evidence of a chain length distribution in the disordered network [22][23][24][25].Nevertheless, information about longer range order, which could be obtained from a three-spin correlation experiment, remains desirable for a better description of the disordered glassy network. Recently, various dipolar recoupling pulse sequences have been proposed to obtain 1 H and 13 C homonuclear through-space triple-quantum -single-quantum (TQ-SQ) correlation spectra in solids [26][27][28][29][30]. A modified INADEQUATE experiment was also proposed to record 13 C through-bond TQ-SQ correlatio...

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Section: Application To Phosphate Glassmentioning

confidence: 99%

Triple-quantum correlation NMR experiments in solids using J-couplings

Fayon

Roiland

Emsley

et al. 2006

Journal of Magnetic Resonance

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show abstract

“…[106]); C k(1) and C k (2) by Massiot and co-workers (Ref. [97]) and Wang and co-workers (Ref. [111]); C 3a C 3b (1) , and C 3b(2) by Amoureux and Fernandez (Refs.…”

Section: Theorymentioning

confidence: 99%

“…These choices were introduced by Massiot and co-workers [97] because they use the evolution period (1 + k)t 1 instead of the experimental evolution period. For these two conventions, the observed chemical shift of the center of gravity of the peak in the F1 dimension or Eq.…”

Section: Theorymentioning

confidence: 99%

“…Otherwise, we have to use conventions whose apparent carrier frequencies are always positive. This is the reason for which conventions C z [38,59,96,98,[106][107][108] and C k(1) [17,29,68,72,77,87,91,93,97,98,[109][110][111] are the most applied.…”

Section: Theorymentioning

confidence: 99%

“…1a). The echo signal is located at t 2 = |k(I p)|t 1 [1,[95][96][97][98][99] and the anti-echo signal at t 2 = −|k(I p)|t 1 , p being the coherence order. Furthermore, the MQ coherence, generated by the first RF pulse and refocused by the second RF pulse as echo, and that refocused as anti-echo have opposite coherence orders.…”

Section: Theorymentioning

confidence: 99%

See 2 more Smart Citations

Procedures for Labeling the High-Resolution Axis of Two-Dimensional MQ-MAS NMR Spectra of Half-Integer Quadrupole Spins

Millot

Man

2002

Solid State Nuclear Magnetic Resonance

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The increasing development and application of the multiple-quantum MAS NMR for halfinteger quadrupole spins has led to various RF pulse sequences for improving the excitation of multiple-quantum coherences and their conversion to single-quantum coherences. As a result, several conventions for labeling the F1 dimension of a 2D MQ-MAS spectrum appear in the literature. The corresponding relations for extracting the isotropic chemical shift, the quadrupole coupling constant, and the asymmetry parameter from experimental data are not always provided. We analyze these various conventions systematically and propose a new one, similar to that introduced by J.-P. Amoureux and C. Fernandez (2000, Solid State NMR 10, 339-343). These various conventions are illustrated with 27 Al (I = 5/2) nuclei in aluminum acetylacetonate Al(CH 3 COCHCOCH 3 ) 3 . Another experimental problem often met, the aliasing of peaks in the 2D spectrum, is analyzed and illustrated with 27 Al (I = 5/2) in NH 4 Y zeolite and 23 Na (I = 3/2) in sodium pyrophosphate Na 4 P 2 O 7 . © 2002 Elsevier Science (USA)

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Spin echoes in half-integer quadrupole systems

Chan

1999

Concepts Magn. Reson.

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Two-dimensional magic-angle spinning isotropic reconstruction sequences for quadrupolar nuclei

Cited by 430 publications

References 14 publications

Triple-quantum correlation NMR experiments in solids using J-couplings

Triple-quantum correlation NMR experiments in solids using J-couplings

Procedures for Labeling the High-Resolution Axis of Two-Dimensional MQ-MAS NMR Spectra of Half-Integer Quadrupole Spins

Spin echoes in half-integer quadrupole systems

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