Tag Archives: NUS

Extraction of ¹J_CH for all carbon multiplicities.

2017-01-20Our Publicationsenhanced resolution, homodecoupling, J-resolved, NUS, PMMA_gelsNúria

“Perfect¹J_CH-resolved HSQC: Efficient measurement of one-bond proton-carbon coupling constants along the indirect dimension” by Núria Marcó, A.A. Souza, Pau Nolis, R. R. Gil and Teodor Parella. Journal of Magnetic resonance 2017, 276, 37-42. DOI: 10.1016/j.jmr.2017.01.002

A versatile ¹J_CH-resolved HSQC pulse scheme for the speedy, accurate and automated determination of one-bond proton-carbon coupling constants is reported. The implementation of a perfectBIRD element allows a straightforward measurement from the clean doublets obtained along the highly resolved F1 dimension, even for each individual ¹J_CHa and ¹J_CHb in diastereotopic H_aCH_b methylene groups. Real-time homodecoupling during acquisition and other alternatives to minimize accidental signal overlapping in overcrowded spectra are also discussed.

Pulse Programs Code for Bruker:

Perfect J_C_H-resolved

Data set Example:

Strychnine

Access to experimentally infeasible spectra by pure-shift NMR covariance

2016-10-04Methods & Applications, Our Publications, Our Research2D DIAG, coavriance, enhanced resolution, Generalized Indirect Covariance, homodecoupling, homonuclear decoupling, HSQC, HSQMBC, HSQMBC-TOCSY, indirect covariance, NOESY, NUS, psGIC, Pure shift, pure-shift NMRAndre

Access to experimentally infeasible spectra by pure-shift NMR covariance. André Fredi, Pau Nolis, Carlos Cobas and Teodor Parella. Journal of Magnetic Resonance, Volume 270, September 2016, Pages 161-168. DOI: 10.1016/j.jmr.2016.07.010

Abstract: Covariance processing is a versatile processing tool to generate synthetic NMR spectral representations without the need to acquire time-consuming experimental datasets. Here we show that even experimentally prohibited NMR spectra can be reconstructed by introducing key features of a reference 1D CHn-edited spectrum into standard 2D spectra. This general procedure is illustrated with the calculation of experimentally infeasible multiplicity-edited pure-shift NMR spectra of some very popular homonuclear (ME-psCOSY and ME-psTOCSY) and heteronuclear (ME-psHSQC-TOCSY and ME-psHMBC) experiments.

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Exploring the use of Generalized Indirect Covariance to Reconstruct Pure shift NMR Spectra: Current Pros and Cons.

2016-03-14Methods & Applications, News from the SeRMN, Our Publications, Our Research2D DIAG, coavriance, enhanced resolution, Generalized Indirect Covariance, homodecoupling, homonuclear decoupling, HSQC, HSQMBC, HSQMBC-TOCSY, indirect covariance, NOESY, NUS, psGIC, Pure shift, pure-shift NMRAndre

Title: Exploring the use of Generalized Indirect Covariance to Reconstruct Pure shift NMR Spectra: Current Pros and Cons.
Authors: André Fredi, Pau Nolis, Carlos Cobas, Gary E. Martin and Teodor Parella.
DOI: 10.1016/j.jmr.2016.03.003

ABSTRACT: The current pros and cons of a processing protocol to generate pure chemical shift NMR spectra using Generalized Indirect Covariance are presented and discussed. The transformation of any standard 2D homonuclear and heteronuclear spectrum to its pure shift counterpart by using a reference DIAG spectrum is described. Reconstructed pure shift NMR spectra of NOESY, HSQC, HSQC-TOCSY and HSQMBC experiments are reported for the target molecule strychnine.

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Ultra-high-resolved NMR: Analysis of complex mixtures of compounds with near-identical ¹H and ¹³C NMR spectra

2015-07-20Methods & Applications, Our Publications, Our Researchenhanced resolution, HOBS, HOBS-HSQC, HOBS-HSQC-TOCSY, HOBS-HSQMBC, homodecoupling, homonuclear decoupling, NUS, Pure shift, pure-shift NMR, spectral aliasingLaura

Title: Disentangling complex mixtures of compounds with near-identical ¹H and ¹³C NMR spectra using pure shift NMR.
Authors: L. Castañar, R. Roldán, P. Clapés, A. Virgili and T. Parella.
Reference: Chem. Eur. J., 2015, 21, 7682-7685.
DOI: 10.1002/chem.201500521

Abstract: The thorough analysis of highly complex NMR spectra using pure shift NMR experiments is described. The enhanced spectral resolution obtained from modern 2D HOBS experiments incorporating spectral aliasing in the ¹³C indirect dimension enables the distinction of similar compounds exhibiting near-identical ¹H and ¹³C NMR spectra. It is shown that a complete set of extremely small Δδ(1H) and Δδ(13C) values, even below the natural line width (1 and 5 ppb, respectively), can be simultaneously determined and assigned.

References:

“Full sensitivity and enhanced resolution in homodecoupled band-selective NMR experiments” Chem. Eur. J. 2013, 19, 17283-17286.

“Simultaneous ¹H and ¹³C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra” Chem. Commun. 2014 50, 10214-10217.

“Implementing homo- and heterodecoupling in region-selective HSQMBC experiments” J. Magn. Reson. 2014, 238, 63-69.

Pulse Programs Code for Bruker:

2D HOBS-HSQC-TOCSY

Data set Example:

Mixture

PhD Thesis by Laura Castañar: Pulse Programs and Data Set Examples

2015-05-31Methods & Applications, News from the SeRMN, NMR Events & Courses, Our Publications, Our Researchaligned-media, coupling-constants, enantiodifferentiation, enhanced resolution, full sensitivity, heteronulear coupling constants, HOBS, HOBS-HSQC, HOBS-HSQC-TOCSY, HOBS-HSQMBC, HOBS-TOCSY, homodecoupling, homonuclear decoupling, HSQC, HSQMBC, J-resolved, multi-slice selection, multiple frequency pulses, NUS, one-bond proton-carbon coupling constants, perfect HSQC, PhD Thesis, PIP experiments, proton-carbon coupling constants, proton-proton coupling constants, pure in-phase signals, Pure shift, quantitative nmr, RDCs, Relaxation times, residual dipolar couplings, resolution enhancement, SAPS-HSQC, sensitivity enhancement, sign of coupling constants, spectral aliasing, T1-relaxation, T2-relaxation, two-bonds proton-proton coupling constantsLaura

Development and application of modern pure shift NMR techniques and improved HSQC/HSQMBC experiments

In the following links one can find Data Set Examples of each Publication presented in the Thesis Work, as well as the corresponding Pulse Program Code for Bruker. All 2D spectra have been previously phased and 2ii, 2ir, and 2ri files removed, otherwise data sets would be too big. Continue reading PhD Thesis by Laura Castañar: Pulse Programs and Data Set Examples →

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