Tag Archives: pure-shift NMR

André Fredi’s oral presentation at 8th GERMN / 5th Iberian NMR Meeting

André Fredi made an oral presentation at the 8th GERMN / 5th Iberian NMR Meeting (GERMN 2016) held in Valencia, Spain from 27th to 29th June 2016.

In his presentation, that was titled  Exploring the use of Generalized Indirect Covariance to reconstruct Pure Shift NMR spectra: Current Pros and Cons”, André explained how to make pure spectra shift from Generalized Indirect IMG-20160628-WA0028Covariance processing (psGIC). This new method is basically a new way to get “synthetic” pure shift spectra without the need to purchase a pure shift spectrum in the spectrometer and without the penalties that pure-shift experiments cause.

André has been working as a Ph.D. candidate at the Department of Chemistry and SeRMN under the direction of Dr. Teodor Parella and Dr. Pau Nolis since November 2014, when he enrolled in the Department of Chemistry doctoral program at Universitat Autònoma de Barcelona with a fellowship from CNPq-Brazil. He is currently in his second year and expects to defend the doctoral thesis on 2017/2018.

 

Presentations at the EUROMAR 2016 Conference

euromar

André Fredi (PhD student) and Teodor Parella presented our last research works at the annual meeting of the European magnetic resonance community EUROMAR 2016 Conference that was celebrated on days 3th to 7th July in Aarhus, Denmark. Find below a summary of our contributions. Continue reading Presentations at the EUROMAR 2016 Conference

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

JMR

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

PhD Thesis: Development and application of modern pure shift NMR techniques and improved HSQC and HSQMBC experiments

Last 16st July 2015 I defended my PhD Thesis entitled: Development and application of modern pure shift NMR techniques and improved HSQC/HSQMBC experiments.

Presentación1

The present doctoral thesis is framed within the Nuclear Magnetic Resonance (NMR) spectroscopy field, more specifically in the design of modern NMR methodologies. The research work carried out is focused on the design and application of new and modern NMR methodologies (i) to perform efficient broadband 1H homodecoupling in 1D/2D NMR experiments and (ii) to accurately determine homo- and heteronuclear coupling constants in isotropic and anisotropic conditions through improved HSQC and HSQMBC-type experiments. The thesis is presented as a compendium ten (10) publications that have been published in several peer-reviewed international scientific journals as original research papers. Continue reading PhD Thesis: Development and application of modern pure shift NMR techniques and improved HSQC and HSQMBC experiments

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

Title: cover7Disentangling 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.

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Review: Recent Advances in Small Molecule NMR: Improved HSQC and HSQMBC Experiments

annrep“Recent Advances in Small Molecule NMR: Improved HSQC and HSQMBC Experiments” by Laura Castañar and Teodor Parella. Annual Reports on NMR Spectroscopy, 2015, 84:163–232. DOI: 10.1016/bs.arnmr.2014.10.004

A general description of the latest developments in heteronuclear single-quantum correlation and heteronuclear single-quantum multiple bond correlation experiments designed for small molecules at the natural isotopic abundance is reported. Continue reading Review: Recent Advances in Small Molecule NMR: Improved HSQC and HSQMBC Experiments

SeRMN presentations at the 2014 Ibero-American NMR & GERMN Bienal & Iberian NMR meeting

Imagen1Some of our last research work will be presented next week at the VI Ibero-American NMR – VII GERMN Bienal – IV Iberian NMR joint meeting that will take place in Alcalá de Henares, Madrid (Spain) from 22nd to 25th September. Find below a summary of our contributions.

Laura Castañar presents an oral communication and a poster entitled “Enantiodifferentiation throgh frequency-selective pure shift 1H NMR”.  NMR-aided discrimination of enantiomers using chiral solvating agents (CSAs) is a well established method to carry out enantiodifferentiation studies. Continue reading SeRMN presentations at the 2014 Ibero-American NMR & GERMN Bienal & Iberian NMR meeting

Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra

CoverIssue“Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra” by Miriam Pérez-Trujillo, Laura Castañar, Eva Monteagudo, Lars T. Kuhn, Pau Nolis, Albert Virgili, R. Thomas Williamson and Teodor Parella. Chemical Communications  50:10214-10217 (2014). DOI: 10.1039/C4CC04077E

NMR-aided discrimination of enantiomers using chiral solvating agents (CSAs) is a well established method of enantiodifferentiation and measurement of enantiomeric ratios (er). The analysis is traditionally performed by observing chemical shift differences (ΔΔδ) in 1H signals by conventional 1D 1H NMR spectra. However, low ΔΔδ values and signal overlap caused by complex multiplets lead to the lack of spectral signal dispersion that preclude a straightforward analysis. Continue reading Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra

Presentations at the EUROMAR 2014 Conference

EUROMAR 2014

In a few days several SeRMN members will present our research work at the annual meeting of the European magnetic resonance community EUROMAR 2014 Conference  that will take place in Zurich (Switzerland) from 29th June to 3th July. Find below a summary of our contributions. Continue reading Presentations at the EUROMAR 2014 Conference

HOBS experiments to measure T1/T2 relaxation times in overlapped regions

S10907807“Measurement of T1/T2 relaxation times in overlapped regions from homodecoupled 1H singlet signals” by Laura Castañar, Pau Nolis, Albert Virgili and Teodor Parella. Journal of Magnetic Resonance 244 (2014) 30-35. DOI: 10.1016/j.jmr.2014.04.003

The implementation of the HOmodecoupled Band-Selective (HOBS) technique in the conventional Inversion-Recovery and CPMG-based PROJECT experiments is described. The achievement of fully homodecoupled signals allows the distinction of overlapped 1H resonances with small chemical shift differences. It is shown that the corresponding T1 and T2 relaxation times can be individually measured from the resulting singlet lines using conventional exponential curve-fitting methods. Continue reading HOBS experiments to measure T1/T2 relaxation times in overlapped regions