Tag Archives: pure in-phase signals

PhD Thesis: New Applications of Covariance NMR and Experimental Development for Measurements of Homonuclear Coupling Constants in Overlapping Signals

On 21st March 2018 I sucessfully defended my PhD Thesis entitled: “New Applications of Covariance NMR and Experimental Development for Measurements of Homonuclear Coupling Constants in Overlapping Signals” (ISBN: 9788449079252), supervised by Dr. Teodor Parella and Dr. Pau Nolis, and obtained the degree of Ph.D. in Chemistry at the Department of Chemistry, Universitat Autònoma de Barcelona.

The thesis can be downloaded in PDF format from the TDX repository and from the TESEO repository.

Accurate measurement of proton homonuclear coupling constants in overlapped signals by using a doubly-selective TOCSY G-SERF experiment.

Abstract

The experimental results obtained in this thesis are presented in the form of three papers published in NMR specialised scientific peer-reviewed journals.

  • Exploring the use of Generalized Indirect Covariance to Reconstruct Pure shift NMR Spectra: Current Pros and Cons. André Fredi, Pau Nolis, Carlos Cobas, Gary E. Martin and Teodor Parella. Journal of Magnetic Resonance, Volume 266, May 2016, Pages 16-22. DOI: 10.1016/j.jmr.2016.03.003
  • 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
  • Accurate measurement of JHH in overlapped signals by a TOCSY‐edited SERF Experiment. André Fredi, Pau Nolis and Teodor Parella. Magnetic Resonance in Chemistry, Volume 55, Issue 6, June 2017, Pages 525-529. DOI: 10.1002/mrc.4572

The first two articles deal with the use of covariance NMR as a general method to generate novel psNMR spectra. The last work describes a new selTOCSY G-SERF experiment, for accurately measuring JHH in overlapped regions.

The first publication describes a novel general protocol to generate psNMR spectra by Covariance NMR. This new approach is unique in NMR spectroscopy; giving a cheap, fast an easy way to reconstruct psNMR spectra without spending time in the spectrometer. This new strategy has been referenced to as psNMR Covariance.

The concept of psNMR Covariance has been extended in the second publication by inserting Multiplicity-Edited (ME) information into 2D experiments that are difficult or even impossible to achieve experimentally. It is shown how the ME information can be efficiently transferred to a set of homonuclear and heteronuclear 2D NMR spectra by Covariance processing, reconstructing new psME spectra in a fast way. Finally, G-SERF and related methods only work for isolated 1H signals on which selective excitation can be successfully applied.

Unfortunately, as it happens in other frequency-selective experiments, this approach fails for overlapped signals. A doubly-selective TOCSY G-SERF scheme is presented in the third publication to circumvent this limitation, by measuring JHH efficiently even for protons resonating in crowded regions.

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

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

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

Presentación1

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

Perfect-HSQC experiments: pure in-phase spectra

cover“Suppresión of phase and amplitude JHH 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, JHH, and proton–carbon, 1JCH, coupling constants. It is shown by spectral simulation and experimentally that JHH 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