Spectral editing in solid-state MAS NMR of quadrupolar nuclei using selective satellite inversion

Dey, Krishna Kishor; Prasad, Subramanian; Ash, Jason T.; Deschamps, Michaël; Grandinetti, Philip J.

doi:10.1016/j.jmr.2006.12.013

Cited by 52 publications

(52 citation statements)

References 23 publications

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“…The most commonly used are the quadrupolar Carr-Purcell-Meiboom-Gill (QCPMG) pulse sequence (based on multiple-pulse spin-echo methods) 36,74-76 and population transfer techniques such as rotor-assisted population transfer (RAPT), 77-80 double frequency sweeps (DFS) 81,82 and use of adiabatic inversion pulses, such as hyperbolic secant (HS) and WURST pulses. [83][84][85][86][87] There are several reviews and original papers about the theoretical and practical aspects involved in these methods. 74,76,84,86,[88][89][90][91][92][93][94][95] In this section, the principles underlying these approaches to signal enhancement are briefly revisited with reports of their applications to solid-state 25 Mg NMR experiments highlighted.…”

Section: Introductionmentioning

confidence: 99%

Recent Advances in Solid-State 25Mg NMR Spectroscopy

Freitas

Smith

2012

Annual Reports on NMR Spectroscopy

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Section: Introductionmentioning

confidence: 99%

Recent Advances in Solid-State 25Mg NMR Spectroscopy

Freitas

Smith

2012

Annual Reports on NMR Spectroscopy

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“…In the case of the adiabatic pulses, the use of either a single pulse or two pulses symmetrically placed around the central transition led to the same result. [14,15,34] These values found for the signal-enhancement factors are somewhat below the theoretical limit expected for a quadrupolar nucleus with half-integer spin in the case of saturation of all satellite transitions (this limit is equal to I + 1/2 for a nucleus with spin I, which means 3.0 for 25 Mg). A larger enhancement factor of 2I (or 5.0 in the case 25 Mg) would be attained in the case of perfect inversion of the satellite transitions in a definite order (first the outer ones, then the inner ones).…”

Section: Implementation and Test Of Signal-enhancement Methodsmentioning

confidence: 63%

“…5 are in agreement with previous work on the optimisation of adiabatic pulses for signal-enhancement of the central transition signal in half-integer spin quadrupolar nuclei. [14,15] For both probes, the signal-enhancement curves show a broad maximum at HS pulse offsets in the region around the most intense singularities of the static powder pattern, which correspond to the most intense spinning sidebands associated with the first-order quadrupolar satellite lines. Also, the signal-enhancement factors decrease for very short or very large offsets, but the actual values of the extreme useable offsets change with the type of probe.…”

Section: Implementation and Test Of Signal-enhancement Methodsmentioning

confidence: 99%

Solid‐state natural abundance ²⁵Mg NMR studies of Na₂MgEDTA·4H₂O—a possible new reference compound for ²⁵Mg NMR spectroscopy

Freitas

Wong

Smith

2008

Magnetic Reson in Chemistry

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Natural abundance solid-state (25)Mg NMR measurements were made of the disodium salt of magnesium ethylenediaminetetraacetate tetrahydrate (Na(2)MgEDTA x 4 H(2)O). Both magic angle spinning (MAS) and static experiments were employed to determine the quadrupole coupling constant (C(q)) and the asymmetry parameter (eta(q)) of the electric field gradient (EFG) tensor associated with (25)Mg in this compound, giving the values C(q) = 1.675(5) MHz and eta(q) = 0.15(1). The isotropic chemical shift was determined to be delta(iso) = 0.25(10) ppm (relative to 11 M MgCl(2) aqueous solution) and a small chemical shift anisotropy (CSA) contribution (approximately -13 ppm) was detected, one of the first CSA reports in (25)Mg NMR. This compound exhibited remarkably good (25)Mg NMR sensitivity, due to its fast spin-lattice relaxation and modest quadrupole coupling, which allowed its use as a secondary shift reference and as a test sample for the implementation and optimisation of signal-enhancement methods in (25)Mg NMR spectroscopy, such as double frequency sweeps (DFS) and the use of adiabatic hyperbolic secant (HS) and WURST pulses.

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“…In addition, Grandinetti and coworkers have recently reported using the closely related Wideband Uniform Rate and Smooth Transition (WURST) pulses for the same purpose. [14] The enhancements achieved in these experiments arise from population transfers from energy levels associated with the satellite transitions, STs, to those for the CT. It has been demonstrated that only one ST spinning side band, ssb, need be irradiated to generate maximum enhancement for MAS powder samples.…”

Section: Introductionmentioning

confidence: 96%

Using hyperbolic secant pulses to assist characterization of chemical shift tensors for half‐integer spin quadrupolar nuclei in MAS powder samples

Nakashima

Teymoori

Wasylishen

2009

Magnetic Reson in Chemistry

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Determination of the NMR anisotropic magnetic shielding parameters from magic angle spinning, MAS, powder samples containing half-integer spin quadrupolar nuclei is achieved by analysis of the difference spectrum obtained with and without application of a hyperbolic secant pulse. Application of a hyperbolic secant pulse to any spinning sideband associated with the central transition, m(I) = 1/2 to m(I) = - 1/2, results in 'saturation' of the entire central transition manifold. Similarly, if one spinning sideband associated with the m(I) = 3/2 to m(I) = 1/2 and m(I) = - 1/2 to m(I) = - 3/2 satellite transitions is perturbed, the entire satellite manifold associated with these transitions is 'saturated' while the central transition is enhanced by population transfer. Three 'difference spectrum' techniques are employed to selectively yield the spinning sidebands associated predominantly from the central transition. The success of these difference techniques is first demonstrated by examining (51)V NMR spectra of three metavanadate salts and (59)Co NMR spectra of Co(acac)(3). The vanadium and cobalt chemical shift tensors in these compounds have spans between 400 and 1400 ppm. Because the hyperbolic secant techniques proposed here yielded results that are in good agreement with earlier reports, they have been applied to characterize the (51)V chemical shift tensor of the dimer of bis(N, N-dimethylhydroxamido)-hydroxooxovanadate, {V(O)(ONMe(2))(2)}(2)O, whose chemical shift tensor has not been previously reported.

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Spectral editing in solid-state MAS NMR of quadrupolar nuclei using selective satellite inversion

Cited by 52 publications

References 23 publications

Recent Advances in Solid-State 25Mg NMR Spectroscopy

Recent Advances in Solid-State 25Mg NMR Spectroscopy

Solid‐state natural abundance ²⁵Mg NMR studies of Na₂MgEDTA·4H₂O—a possible new reference compound for ²⁵Mg NMR spectroscopy

Using hyperbolic secant pulses to assist characterization of chemical shift tensors for half‐integer spin quadrupolar nuclei in MAS powder samples

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Spectral editing in solid-state MAS NMR of quadrupolar nuclei using selective satellite inversion

Cited by 52 publications

References 23 publications

Recent Advances in Solid-State 25Mg NMR Spectroscopy

Recent Advances in Solid-State 25Mg NMR Spectroscopy

Solid‐state natural abundance 25Mg NMR studies of Na2MgEDTA·4H2O—a possible new reference compound for 25Mg NMR spectroscopy

Using hyperbolic secant pulses to assist characterization of chemical shift tensors for half‐integer spin quadrupolar nuclei in MAS powder samples

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Solid‐state natural abundance ²⁵Mg NMR studies of Na₂MgEDTA·4H₂O—a possible new reference compound for ²⁵Mg NMR spectroscopy