Application of unsymmetrical indirect covariance NMR methods to the computation of the 13C↔15N HSQC‐IMPEACH and 13C↔15N HMBC‐IMPEACH correlation spectra

  title={Application of unsymmetrical indirect covariance NMR methods to the computation of the 13C↔15N HSQC‐IMPEACH and 13C↔15N HMBC‐IMPEACH correlation spectra},
  author={Gary E. Martin and Bruce D. Hilton and Patrick A. Irish and Kirill A. Blinov and Antony J. Williams},
  journal={Magnetic Resonance in Chemistry},
Utilization of long‐range 1H15N heteronuclear chemical shift correlation has continually grown in importance since the first applications were reported in 1995. More recently, indirect covariance NMR methods have been introduced followed by the development of unsymmetrical indirect covariance processing methods. The latter technique has been shown to allow the calculation of hyphenated 2D NMR data matrices from more readily acquired nonhyphenated 2D NMR spectra. We recently reported the use of… 
18 Citations

Utilizing Long‐Range 1H–15N 2‐D NMR Spectroscopy for Chemical Structure Elucidation and Confirmation

15N can almost be considered a “forgotten” nuclide because of its low natural abundance, low γ, and the historical difficulty of direct observation NMR experiments. Indirect detection methods,

Using indirect covariance spectra to identify artifact responses in unsymmetrical indirect covariance calculated spectra

Responses contained in indirect covariance processed HSQC spectra are reported as a means for the identification of artifacts in bothirect covariance and unsymmetrical indirect covariances processed 2D NMR spectra.

HSQC–ADEQUATE correlation: a new paradigm for establishing a molecular skeleton

The unsymmetrical indirect covariance processing of multiplicity‐edited GHSQC and 1,1‐ADEQUATE spectra are explored to afford an HSQC–ADEquATE correlation spectrum that facilitates the extraction of carbon‐carbon connectivity information.

Multistep correlations via covariance processing of COSY/GCOSY spectra: opportunities and artifacts

Results obtained from covariance‐processed GCOSY spectra are fully analyzed and compared to normally processed COSY and 80 ms TOCSY spectra and the origin of artifact responses is analyzed.

HSQC‐ADEQUATE: an investigation of data requirements

The results of an investigation of the reduction in acquisition time for the 1,1‐ADEQUATE data to take advantage of the s/n gain during the UIC processing to afford the final HSQC‐ADEquATE correlation plot are reported.

Covariance nuclear magnetic resonance methods for obtaining protein assignments and novel correlations.

  • A. KancherlaD. Frueh
  • Chemistry
    Concepts in magnetic resonance. Part A, Bridging education and research
  • 2017
Advances in covariance NMR are highlighted that permitted to generate reliable 4D arrays and how these arrays can be obtained from conventional NMR spectra are described.

Posaconazole: Application of HSQC‐ADEQUATE from General Indirect Covariance Processing

The 1,1-ADEQUATE experiment provides unequivocal experimental access to adjacent carbon–carbon correlation information, albeit with a sensitivity penalty, as the experiment involves an adjacent 13C–13C out-and-back magnetization transfer.

Homo- and Hetero-Covariance NMR Spectroscopy and Applications to Process Analytical Technology

Covariance processing of data and spectra has established itself among the computerbased NMR spectroscopy methodologies to increase sensitivity and resolution and to facilitate spectral analysis.



13C-15N Connectivity networks via unsymmetrical indirect covariance processing of 1H-13C HSQC and 1H

Long-range 1H-15N heteronuclear shift correlation methods at natural abundance to facilitate the elucidation of small molecule structures have assumed a role of growing importance over the past

Analysis and elimination of artifacts in indirect covariance NMR spectra via unsymmetrical processing

Using an IDR (inverted direct response)‐HSQC‐TOCSY spectrum as a starting point for the indirect covariance processing, a spectrum that can be described as a carbon–carbon COSY experiment is obtained, and data are analogous to the autocorrelated 13C–13C double quantum INADEQUATE experiment except that the direct covariance NMR spectrum establishes carbon– carbon connectivities only between contiguous protonated carbons.

Utilizing unsymmetrical indirect covariance processing to define 15N13C connectivity networks

The utilization of unsymmetrical indirect covariance NMR methods for the combination of 1H13C GHSQC and 1H 15N long‐range (GHMBC, IMPEACH‐ MBC, CIGAR‐HMBC, etc.) heteronuclear chemical shift correlation spectra to determine 15N13C correlation pathways is reported.

Unsymmetrical covariance processing of COSY or TOCSY and HSQC NMR data to obtain the equivalent of HSQC‐COSY or HSQC‐TOCSY spectra

Artifacts observed in the indirect covariance NMR spectrum of HSQC-TOCSY data have recently been analyzed and a method for their elimination proposed. More recently, unsymmetrical covariance

Long‐range carbon–carbon connectivity via unsymmetrical indirect covariance processing of HSQC and HMBC NMR data

Using experimentally discrete HSQC and HMBC data sets, it is shown that unsymmetrical indirect covariance processing of the pair of NMR spectra affords a presentation containing long‐range carbon–carbon connectivity information.

The use of unsymmetrical indirect covariance NMR methods to obtain the equivalent of HSQC‐NOESY data

The application of the unsymmetrical indirect covariance NMR methods to the combination of HSQC and NOESY spectra is demonstrated to provide results comparable toHSQC‐NOESY data, albeit with greater sensitivity and with considerably less spectrometer time.

Long‐range 1H‐15N correlation at natural abundance using gradient‐enhanced inverse‐detection

Inverse-detected heteronuclear shift correlation efficiency has been significantly augmented by the incorporation of pulsed field gradients (PFG). Phase-cycling requirements for t1-noise suppression

Application of accordion excitation in 1H– 15N long‐range heteronuclear shift correlation experiments at natural abundance

Accordion excitation provides the means of sampling a broad range of potential long‐range heteronuclear couplings in a single experiment. Two long‐range heteronuclear experiments, ACCORD‐HMBC and

A robust method for determining 1H–15N long‐range correlations: 15N optimized CIGAR‐HMBC experiments

An examination of a variety of common nitrogen‐containing systems was undertaken to optimize parameters for observation of 1H–15N long‐range correlations. Because of the diversity of coupling

15N NMR Spectroscopy in Structural Analysis

The implementation of both the directly and the inversely detected 15N NMR techniques at the natural abundance level of the 15N isotope is demonstrated for a diverse array of structural problems in