Broadband <sup>13</sup>C‐Homodecoupled Heteronuclear Single‐Quantum Correlation Nuclear Magnetic Resonance

Foroozandeh, Mohammadali; Giraudeau, Patrick; Jeannerat, Damien

doi:10.1002/cphc.201100411

Cited by 20 publications

(23 citation statements)

References 26 publications

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“…The fact that 13 C are easily decoupled at natural abundance and produce narrow singlets explains why most applications of aliasing techniques were focused on the 13 C dimension of heteronuclear experiments. [14][15][16] When the scalar coupling patterns are complex, as in 1 H spectra, but also in 13 C-enriched compounds, [17] homonuclear decoupling is necessary to create enough space between the signals to permit aliased signals to fit in between. Even if 1 H spectra are about five times narrower than 13 C when measured in Hz, the potential of improvement of the resolution is quite interesting.…”

Section: Combination With Spatial Encoding Methodologymentioning

confidence: 99%

“…[16] The fact that accidental overlap may occur when pairs of signals accidentally share the same last digits (for example a signal at 3.234 ppm) sometimes requires a complementary spectrum to be recorded with a slightly different window (say 1.05 ppm) to insure that pairs of signals overlapping in the first spectrum will not overlap in the second. [17] The same principle can be applied to a 100-fold reduction of the number of time increments with a window of 0.1 ppm. In this case, the limit in resolution is achieved since the maximal t 1 evolution time reaches 1 s (the limit imposed by B 0 inhomogeneities to small molecules) with only 100 increments at 500 MHz 1 H Larmor frequency.…”

Section: Combination With Spatial Encoding Methodologymentioning

confidence: 99%

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Combination of Homonuclear Decoupling and Spectral Aliasing to Increase the Resolution in the 1H Dimension of 2D NMR Experiments

Cotte

Foroozandeh

Jeannerat

2012

Chimia

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Broadband homonuclear decoupling (BBHD) in the indirect 1 H dimension of 2D experiments can be obtained using a modified Zangger and Sterk combination of a selective pulse with a pulsed-field gradient. The coupling structure of signals is reduced to a singlet along the F1 dimension at the cost of a sensitivity loss. With the classical sampling in F1, the full resolving power of BBHD-experiments requires very long acquisition times. Spectral aliasing can reduce the number of time increments accessing the top resolution of homodecoupled spectra of small molecules by two orders of magnitude. The TOCSY spectra of androst-4-ene-3,17-dione are shown as an example.

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Section: Combination With Spatial Encoding Methodologymentioning

confidence: 99%

Section: Combination With Spatial Encoding Methodologymentioning

confidence: 99%

Combination of Homonuclear Decoupling and Spectral Aliasing to Increase the Resolution in the 1H Dimension of 2D NMR Experiments

Cotte

Foroozandeh

Jeannerat

2012

Chimia

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“…36,37 The signal intensity variations associated with constant-time experiments are avoided but the general reduction in signal intensity and large amount of time required to acquire the increments needed for good digital resolution in the indirect dimension generally favor pure shift in the direct dimension. These methods may however prove a good alternative to the constant-time methods, especially for systems with a large variety of coupling constants.…”

Section: Multidimensional Experimentsmentioning

confidence: 99%

Pure Shift NMR Spectroscopy

Adams

2014

eMagRes

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Pure shift NMR spectroscopy, or broadband homonuclear decoupled NMR spectroscopy, produces NMR spectra that contain only chemical shift information. In a pure shift NMR spectrum the effects of J-coupling are hidden so that all multiplets are collapsed to singlets. Pure shift methods can deliver a significant improvement in resolution of NMR signals and greatly reduce signal overlap. Pure shift NMR can be achieved using direct or indirect acquisition; for direct acquisition, real-time-or interferogram-based FID collection can be used. The range of pure shift methods includes those that refocus the effects of J-coupling (BIRD, Zangger-Sterk, band selective decoupling, and anti z-COSY); manipulate the evolution of chemical shift within a constant time delay to keep the J-evolution in an indirect acquisition constant; or extract a 1-D spectrum from a 2-D J dataset. The methods and their mechanisms in weakly coupled systems are described using the product operator formalism. Examples are provided for a range of applications.

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“…(Homodecoupling has previously been described for the HSQC experiment, but only in the indirect ( 13 C) dimension. [20] )The HSQC experiment is the most widely used NMR method for correlating the chemical shifts of directly-bonded 13 C-1 H pairs. In its conventional [21] form, it shows proton multiplet structure in F 2 , which limits resolution in the spectra of complex species.…”

mentioning

confidence: 99%

“…(Homodecoupling has previously been described for the HSQC experiment, but only in the indirect ( 13 C) dimension. [20] )…”

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confidence: 99%

Simultaneously Enhancing Spectral Resolution and Sensitivity in Heteronuclear Correlation NMR Spectroscopy

et al. 2013

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A method for acquiring pure shift heteronuclear single quantum correlation (HSQC) NMR spectra in real time is described. A windowed acquisition scheme consisting of trains of bilinear rotation decoupling (BIRD) [1,2] refocusing elements is used to acquire chunks of data with refocused J HH modulation while suppressing J XH with broadband heteronuclear decoupling. The resultant spectra show both enhanced resolution in F 2 and enhanced signal-to-noise ratio.Scalar spin-spin (J) coupling provides valuable information for molecular structure elucidation, but the multiplet structure it causes is very expensive in terms of spectral resolution. In 1 H NMR spectroscopy, multiplets are often many times the width of a single line. It is routine to suppress heteronuclear couplings (J XH ) by broadband decoupling, [3][4][5][6][7] but only recently have experimental methods for homonuclear broadband decoupling become practical. These "pure shift" or "chemical-shift resolved" or "d-resolved" methods [8][9][10][11][12][13][14][15][16][17][18][19] can give resolution improvements approaching an order of magnitude, far in excess of any gains to be realistically expected from increases in the static magnetic field. However, all of these methods suffer to a greater or lesser extent from reduced sensitivity compared to conventional measurements. Here we describe an experimental method for obtaining pure shift heteronuclear single quantum correlation (HSQC) spectra, in which real-time homodecoupling using the BIRD pulse sequence element [1] leads to the first simultaneous resolution and signal enhancement in the directly detected ( 1 H) dimension. (Homodecoupling has previously been described for the HSQC experiment, but only in the indirect ( 13 C) dimension. [20] )The HSQC experiment is the most widely used NMR method for correlating the chemical shifts of directly-bonded 13 C-1 H pairs. In its conventional [21] form, it shows proton multiplet structure in F 2 , which limits resolution in the spectra of complex species. It has recently been shown [17,22,23] that it is possible to extend the pure shift methods currently used, which rely on stitching together separate measurements of short periods of decoupled signal, to real-time acquisition, in which homonuclear couplings are periodically refocused, by applying appropriate spin manipulations during the acquisition of a single free-induction decay. Such J-refocusing sequence elements are generally designed to be broadband, as distinct from classical selective [24,25] or band-selective [26] homodecoupling; in the case of HSQC, J-refocusing uses a BIRD pulse sequence element and a hard (nonselective) 1808 pulse. The BIRD sequence element, [1] which, as its name suggests, was originally intended for broadband homonuclear decoupling, has, until recently, [12] been used almost exclusively for decoupling in the indirect dimension of heteronuclear 2D experiments. [27] Here, the combined effect of the BIRD sequence and the hard 1808 pulse is to invert only those protons not directly couple...

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Broadband ¹³C‐Homodecoupled Heteronuclear Single‐Quantum Correlation Nuclear Magnetic Resonance

Cited by 20 publications

References 26 publications

Combination of Homonuclear Decoupling and Spectral Aliasing to Increase the Resolution in the 1H Dimension of 2D NMR Experiments

Combination of Homonuclear Decoupling and Spectral Aliasing to Increase the Resolution in the 1H Dimension of 2D NMR Experiments

Pure Shift NMR Spectroscopy

Simultaneously Enhancing Spectral Resolution and Sensitivity in Heteronuclear Correlation NMR Spectroscopy

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Broadband 13C‐Homodecoupled Heteronuclear Single‐Quantum Correlation Nuclear Magnetic Resonance

Cited by 20 publications

References 26 publications

Combination of Homonuclear Decoupling and Spectral Aliasing to Increase the Resolution in the 1H Dimension of 2D NMR Experiments

Combination of Homonuclear Decoupling and Spectral Aliasing to Increase the Resolution in the 1H Dimension of 2D NMR Experiments

Pure Shift NMR Spectroscopy

Simultaneously Enhancing Spectral Resolution and Sensitivity in Heteronuclear Correlation NMR Spectroscopy

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Product

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Broadband ¹³C‐Homodecoupled Heteronuclear Single‐Quantum Correlation Nuclear Magnetic Resonance