The ENC Ritchey Travel Award to advanced Ph.D. students was established to honor William M. Ritchey, who was Professor Emeritus of Chemistry and Macromolecular Science at Case Western Reserve University and founder of the ENC. Professor William Ritchey founded the ENC in 1960 when he organized a rather informal meeting to discuss experimental problems with early nmr spectrometer and «we decided to meet again the next year and possibly a few more times and to keep our focus on experimental aspects of NMR.» The areas of the Award are to reflect Professor Ritchey’s broad interests in the development and application of NMR to chemical and material sciences.
As part of the award, Laura gave the oral presentation entitled “HOBS: Broadband Homonuclear Decoupled Band-Selective NMR Experiments with Full Sensitivity” in which she explained a novel NMR approach for recording broadband HOmodecoupled Band-Selective (HOBS) NMR spectra with full sensitivity. The HOBS technique allows recording fully homodecoupled singlet signals from chosen parts of the 1H spectrum without loss of sensitivity.
She also described the straightforward implementation of the HOBS technique for a number of homo and heteronuclear multidimensional experiments (e.g. HOBS-TOCSY, HOBS-HSQC, HOBS-HSQMBC, and more) and she demonstrated that this technique had an ample range of practical applications like the direct measurement of nJCH, the determination of T1 and T2 NMR relaxation times, and enantiodifferentiation studies, among other.
Laura has been working as a Ph.D. candidate at the Department of Chemistry and SeRMN under the co-direction of Dr. Albert Virgili and Dr. Teodor Parella since Sept 2012, when she enrolled in the Department of Chemistry doctoral program at Universitat Autònoma de Barcelona with a fellowship from UAB. She is currently in her third year and expects to defend the doctoral thesis before the summer holiday. You can read about her work on this blog.
In recent years, a great interest in the development of new broadband 1H homonuclear decoupled techniques providing simplified JHH 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. A detailed discussion about the most relevant practical aspects in terms of pulse sequence design, selectivity, sensitivity, spectral resolution and performance is provided. Finally, the implementation of the different reported strategies into traditional 1D and 2D NMR experiments is described while several practical applications are also reviewed.
Abstract: Recently, a novel NMR approach for recording broadband HOmodecoupled Band-Selective (HOBS) NMR spectra with full sensitivity has been reported. The HOBS technique is a frequency-selective experiment which affords fully homodecoupled singlet signals in particular areas of the 1H spectrum without sacrificing sensitivity, allowing the fast NMR data acquisition in the same experimental times as regular experiments. Here we present the easy and reliable implementation of the HOBS technique for a number of homo and heteronuclear multidimensional experiments, such as HOBS-TOCSY, HOBS-HSQC, HOBS-HSQMBC, HOBS Inversion-Recovery and HOBS-CPMG-PROJECT. In addition, its practical utility in a wide range of applications, covering the direct measurement of nJCH, the determination of T1 and T2 NMR relaxation times and the enantiodifferentiation studies, among other.
NMR-aided enantiodiscrimination using chiral auxiliaries (CAs) is a recognized method for differentiating enantiomers and for measuring enantiomeric ratios (er). Up to the present, the study, optimization, and comparison of such methods have been performed based on the enantiodifferentiation of NMR signals via analysing non-equivalent chemical-shift values (ΔΔδ) of the diastereoisomeric species formed. However, a poor and non-reliable comparison of results is often obtained via the analysis of ΔΔδ exclusively. In here, the concept of enantioresolution of an individual NMR signal and its importance for NMR-aided enantiodifferentiation studies is introduced and discussed. In addition, the enantioresolution quotient, E, is proposed as the parameter to describe its quantification. Complementary to ΔΔδ, the experimental determination of E allows a more reliable interpretation of the results and opens up new possibilities for the study of enantiodifferentiation data derived from novel NMR experiments, setup improvements or new CAs.
“In vivo and ex vivo Magnetic Resonance Spectroscopy of the Infarct and the Subventricular Zone in Experimental Stroke” by E. Jiménez-Xarrié, M. Davila, S. Gil-Perotín, A. Jurado-Rodríguez, A.P. Candiota, R. Delgado-Mederos, S. Lope-Piedrafita, J.M. García-Verdugo, C. Arús, J. Martí-Fàbregas. Journal of Cerebral Blood Flow & Metabolism, 2015, 35:828–834. DOI: 10.1038/jcbfm.2014.257
Ischemic stroke changes the metabolic pattern in the infarct area and also in other regions such as the ipsilateral subventricular zone (SVZi) where neural progenitor cells (NPCs) proliferation is enhanced in the mammalian and human brains. Magnetic resonance spectroscopy (MRS) provides metabolic information in vivo. With regard to NPCs proliferation, a resonance at 1.28 ppm has been described as an in vivo MRS biomarker of NPCs in the hippocampus of rats and humans. Continue reading In vivo MRS and ex vivo HRMAS in an Ischemic Rat Stroke Model→
“A Benzyl Alcohol Derivative of BDPA Radical for Fast Dissolution Dynamic Nuclear Polarization NMR Spectroscopy” by José Luis Muñoz Gómez, Eva Monteagudo, Vega Lloveras, Teodor Parella, Jaume Veciana and José Vidal Gancedo. Organic & Biomolecular Chemistry, 2015, 13:2689-2693. DOI: 10.1039/C4OB02356K
The synthesis, structural characterization and the successful application of a carbon centered radical derived from 1,3-bisdiphenylene-2-phenylallyl (BDPA), its benzyl alcohol derivative (BA-BDPA), as a polarizing agent for Dynamic Nuclear Polarization (DNP) are described. Continue reading A New Polarizing Agent for Dissolution-DNP→
A rapid NMR data acquisition strategy in terms of enhanced resolution per time unit for the simple and efficient determination of multiple coupling constants is described. The use of 13C spectral aliasing combined with broadband 1H homodecoupling allows accurate measurements from ultra high resolved 2D HSQC cross-peaks.