All posts by Laura

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

2015-07-27Methods & Applications, News from the SeRMN, Our Researchcoupling-constants, enhanced resolution, full sensitivity, HOBS, homonuclear decoupling, HSQC, HSQMBC, perfect HSQC, PhD Thesis, PIP experiments, pure in-phase signals, pure-shift NMR, residual dipolar couplings, SAPS-HSQC, sensitivity enhancementLaura

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

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

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 →

Review – Pure shift NMR experiments: recent developments, methods and applications

2015-05-02Methods & Applications, NMR Bibliography, Our Publications, Our Researchenantiodifferentiation, enhanced resolution, full sensitivity, heteronulear coupling constants, HOBS, HOBS-HSQC, HOBS-HSQMBC, HOBS-TOCSY, homodecoupling, homonuclear decoupling, Pure shift, Relaxation times, resolution enhancement, review, SAPS-HSQC, sensitivity enhancement, T1-relaxation, T2-relaxationLaura

“Broadband ¹H homodecoupled NMR experiments: recent developments, methods and applications” by Laura Castañar and Teodor Parella. Magnetic Resonance in Chemistry, 2015. DOI: 10.1002/mrc.4238

In recent years, a great interest in the development of new broadband ¹H homonuclear decoupled techniques providing simplified J_HH multiplet patterns has emerged again in the field of small molecule NMR. The resulting highly resolved ¹H NMR spectra display resonances as collapsed singlets, therefore minimizing signal overlap and expediting spectral analysis. This review aims at presenting the most recent advances in pure shift NMR spectroscopy, with a particular emphasis to the Zangger–Sterk experiment. Continue reading Review – Pure shift NMR experiments: recent developments, methods and applications →

SeRMN presentation at the 56th ENC 2015 Conference

2015-04-23NMR Events & CoursesENC, HOBS, HOBS-HSQC, HOBS-HSQMBC, HOBS-TOCSY, homodecoupling, NMR Conference, Pure shift, spectral aliasingLaura

During these days takes place the 56^th Experimental Nuclear Magnetic Resonance Conference (ENC) in Asilomar Conference Grounds (Pacific Grove, California, USA) where Laura Castañar presents an Oral Communication entitled “HOBS: Broadband Homonuclear Decoupled Band-Selective NMR Experiments with Full Sensitivity” Continue reading SeRMN presentation at the 56th ENC 2015 Conference →

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

2015-03-02Methods & Applications, NMR Bibliography, Our Publications, Our ResearchHOBS-HSQC, HOBS-HSQMBC, HSQC, HSQMBC, IPAP, nmr, one-bond proton-carbon coupling constants, perfect HSQC, PIP experiments, proton-carbon coupling constants, pure-shift NMR, quantitative nmr, SAPS-HSQCLaura

“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 →

Perfect-HSQC experiments: pure in-phase spectra

2014-10-04Methods & Applications, Our Publications, Our Researchheteronulear coupling constants, HSQC, one-bond proton-carbon coupling constants, perfect HSQC, proton-proton coupling constants, pure in-phase signalsLaura

“Suppresión of phase and amplitude J_HH modulations in HSQC experiments” by Laura Castañar, Eduard Sistaré, Albert Virgili, Robert Thomas Williamson and Teodor Parella. Magnetic Resonance in Chemistry, 2014 , 53:115-119. DOI: 10.1002/mrc.4149

The amplitude and the phase of cross peaks in conventional 2D HSQC experiments are modulated by both proton–proton, J_HH, and proton–carbon, ¹J_CH, coupling constants. It is shown by spectral simulation and experimentally that J_HH interferences are suppressed in a novel perfect-HSQC pulse scheme that incorporates perfect-echo INEPT periods. Continue reading Perfect-HSQC experiments: pure in-phase spectra →

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

2014-09-15Methods & Applications, NMR Events & Courses, Our Researchchirality, enantiodifferentiation, enhanced resolution, full sensitivity, HOBS, HOBS-TOCSY, homodecoupling, homonuclear decoupling, multipl, pure-shift NMRLaura

Some 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 22^nd to 25^th 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 →

Pure In-Phase Heteronuclear Correlation NMR Experiments

2014-06-27Methods & Applications, Our Publications, Our Researchheteronulear coupling constants, HSQC, HSQMBC, IPAP, PIP experiments, proton-carbon coupling constants, proton-proton coupling constantsLaura

“Pure In-Phase Heteronuclear Correlation NMR Experiments ” by Laura Castañar, Josep Sauri, Robert Thomas Williamson, Albert Virgili and Teodor Parella. Angew. Chem. Int. Ed. 2014, 53, 8379-8382. DOI: 10.1002/anie.201404136

A general NMR approach to provide pure in-phase (PIP) multiplets in heteronuclear correlation experiments is described. The implementation of a z-filter efficiently suppresses any unwanted anti-phase contributions that usually distort the multiplet pattern of cross-peaks and can make their analysis difficult. Continue reading Pure In-Phase Heteronuclear Correlation NMR Experiments →

Presentations at the EUROMAR 2014 Conference

2014-06-18News from the SeRMN, NMR Events & Courses, Our Researchenantiodifferentiation, EUROMAR, heteronulear coupling constants, HOBS, homonuclear decoupling, NMR Conference, pure-shift NMRLaura

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 29^thJune to 3^th July. Find below a summary of our contributions. Continue reading Presentations at the EUROMAR 2014 Conference →

SeRMN – NMR Service at UAB

Research & development, training, and facility management