Analyses, extensions and comparison of three experimental schemes for measuring (nJCH+DCH)-couplings at natural abundance

Kobzar, Kyryl; Luy, Burkhard

doi:10.1016/j.jmr.2007.02.005

Cited by 57 publications

(52 citation statements)

References 70 publications

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“…[4] Note that in our hands, the use of a CPMG train within the BIRD pulse as proposed in the CAGEBIRD sequence [12] gave no further improvement. Afterwards, the magnetization is transferred to the carbons by a 90…”

Section: Description Of the Modified Hsqmbc Experimentsmentioning

confidence: 66%

“…[11] The use of CPMG cycle within the G-BIRD filter was also suggested by Luy and Kobzar. [12] It is important to note, however, that the CPMG sequence has an inherent limitation due to the train of highpower pulses, causing unavoidable heating of the electronics of the probehead and the sample. [13] The heating is even more intensive when composite 180…”

Section: Introductionmentioning

confidence: 99%

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Low‐power composite CPMG HSQMBC experiment for accurate measurement of long‐range heteronuclear coupling constants

Boros¹,

Kövér

2011

Magnetic Reson in Chemistry

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A modified version of CPMG-HSQMBC pulse scheme is presented for the measurement of long-range heteronuclear coupling constants. The method implements adiabatic inversion and refocusing pulses on the heteronucleus. Low-power composite 180° XY-16 CPMG pulse train is applied on both proton and X nuclei during the evolution of long-range couplings to eliminate phase distortions due to co-evolution of homonuclear proton-proton couplings. The pulse sequence yields pure absorption antiphase multiplets allowing precise and direct measurement of the (n)J(XH) coupling constants regardless from the size of the proton-proton couplings. The applicability of the method is demonstrated using strychnine as a model compound. The selective 1D version of the method is also presented.

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Section: Description Of the Modified Hsqmbc Experimentsmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Low‐power composite CPMG HSQMBC experiment for accurate measurement of long‐range heteronuclear coupling constants

Boros¹,

Kövér

2011

Magnetic Reson in Chemistry

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“…[5] This problem was alleviated by replacing the rectangular proton and carbon pulses in the INEPT block with CPMG pulse trains to 'decouple' the homonuclear couplings, [16] although a detailed analysis of the available CPMGtype experiments revealed certain limitations, such as the active bandwidth for reasonable suppression of homonuclear antiphase coherences. [17] The pure absorptive in-phase character of the resulting signal and the absence of modulation from passive homonuclear couplings are advantages of the SELINCOR variant over the conventional 1D HSQMBC sequence and measurement of H-C couplings is simpler and more precise. However, the presence of a second INEPT period and two additional shaped pulses imply a loss of sensitivity relative to the 1D HSQMBC sequence, which is a limitation for molecules with short T 2 times, although this is not the typical situation in small molecules as targets for this pulse sequence.…”

Section: Resultsmentioning

confidence: 99%

Measurement of long‐range proton–carbon coupling constants from pure in‐phase 1D multiplets

Espinosa

Vidal

Parella

et al. 2011

Magnetic Reson in Chemistry

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The SELective INverse detection of carbon-proton CORrelation pulse sequence that yields a 1D spectrum of a proton directly bonded to a selected carbon resonance has been converted into a proton and carbon double-selective variant that provides a (1)H spectrum of a selected proton that is long-range coupled to a specific carbon resonance. The resulting 1D proton multiplet exhibits a pure absorptive in-phase lineshape for precise measurement of specific long-range proton-carbon coupling constants in small organic molecules at natural abundance.

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“…Thus, a myriad of NMR experiments have been reported for such a purpose. [24][25][26][27][28][29][30] Marquez et al gave an account of NMR experiments with a collection of more than a hundred references for the measurement of n J XH . [14] In the following sections, recent 2D and 3D techniques based on either the exclusive correlation spectroscopy (E-COSY) concept developed by Griesinger et al [31,32] or spin-selective detection of cross-peak multiplets are discussed.…”

Section: Overview Of Recent Techniquesmentioning

confidence: 99%

Measurement and Applications of Long‐Range Heteronuclear Scalar Couplings: Recent Experimental and Theoretical Developments

2012

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The use of long-range heteronuclear couplings, in association with (1)H-(1)H scalar couplings and NOE restraints, has acquired growing importance for the determination of the relative stereochemistry, and structural and conformational information of organic and biological molecules. However, the routine use of such couplings is hindered by the inherent difficulties in their measurement. Prior to the advancement in experimental techniques, both long-range homo- and heteronuclear scalar couplings were not easily accessible, especially for very large molecules. The development of a large number of multidimensional NMR experimental methodologies has alleviated the complications associated with the measurement of couplings of smaller strengths. Subsequent application of these methods and the utilization of determined J-couplings for structure calculations have revolutionized this area of research. Problems in organic, inorganic and biophysical chemistry have also been solved by utilizing the short- and long-range heteronuclear couplings. In this minireview, we discuss the advantages and limitations of a number of experimental techniques reported in recent times for the measurement of long-range heteronuclear couplings and a few selected applications of such couplings. This includes the study of medium- to larger-sized molecules in a variety of applications, especially in the study of hydrogen bonding in biological systems. The utilization of these couplings in conjunction with theoretical calculations to arrive at conclusions on the hyperconjugation, configurational analysis and the effect of the electronegativity of the substituents is also discussed.

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Analyses, extensions and comparison of three experimental schemes for measuring (nJCH+DCH)-couplings at natural abundance

Cited by 57 publications

References 70 publications

Low‐power composite CPMG HSQMBC experiment for accurate measurement of long‐range heteronuclear coupling constants

Low‐power composite CPMG HSQMBC experiment for accurate measurement of long‐range heteronuclear coupling constants

Measurement of long‐range proton–carbon coupling constants from pure in‐phase 1D multiplets

Measurement and Applications of Long‐Range Heteronuclear Scalar Couplings: Recent Experimental and Theoretical Developments

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