Magnetic Resonance in Chemistry最新文献

{"title":"A Stopped-Flow Instrument for Millisecond Timescale Reaction Monitoring on a Standard NMR Spectrometer","authors":"Andrew M. R. Hall,&nbsp;Edward J. King,&nbsp;Lloyd A. L. Mitchell,&nbsp;George A. Steedman,&nbsp;Stuart Johnstone,&nbsp;Clark Landis,&nbsp;Guy C. Lloyd-Jones","doi":"10.1002/mrc.70114","DOIUrl":"10.1002/mrc.70114","url":null,"abstract":"<p>We report a new stopped-flow instrument designed for initiation and analysis of rapid reactions using standard NMR spectrometers and probes. The instrument is capable of kinetic measurements on mixing-initiated reactions with half-lives as short as 5 milliseconds. Design features of the instrument are discussed, with high-speed video footage, pressure and NMR line-shape data used to characterise mixing and stopping of reagent flows. The reactants are thermally and magnetically equilibrated prior to initiation of mixing and transport of the nascent reaction to the active volume for application of the NMR pulse sequence, ensuring near-quantitative results. NMR data acquisition and processing require special considerations for fast reactions, and simulations were carried out to investigate the effect of composite instrument dead times on the observed rate constant. The kinetics of base-mediated hydrolysis of methyl formate (¹H) and pentafluorophenyl boronic acid (¹⁹F) are employed to demonstrate the capability of the stopped-flow instrument for the reproducible generation of NMR data from fast reactions. Full details of the design and construction of the instrument, together with engineering and electronics drawings, are provided as supporting information. The system requires no permanent modifications to the spectrometer or console.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 8","pages":"711-728"},"PeriodicalIF":2.1,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.70114","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147839836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Practical Guide and Best Practices for Diffusion NMR Processing With GNAT","authors":"Tadeu Luiz Gomes Cabral,&nbsp;Guilherme Dal Poggetto,&nbsp;Claudio F. Tormena,&nbsp;Mathias Nilsson","doi":"10.1002/mrc.70110","DOIUrl":"10.1002/mrc.70110","url":null,"abstract":"<p>Diffusion-NMR, including diffusion-ordered spectroscopy (DOSY), is a powerful technique for measuring self-diffusion and inferring molecular size, shape, aggregation, and intermolecular interactions in solution. Its noninvasive nature and ability to separate components in complex mixtures have made DOSY widely used across chemistry, biochemistry, and materials science. However, accurate and reproducible diffusion measurements depend not only on careful experimental design but also on robust, transparent, and consistent data processing. Despite the growing adoption of diffusion-NMR, widely adopted protocols, practical tutorials, and broadly accepted guidelines for DOSY data analysis remain limited, contributing to variability in reported diffusion coefficients and reduced comparability between studies. The General NMR Analysis Toolbox (GNAT) is a free, open-source platform for visualizing and analyzing diffusion-NMR data. In this article, we present a clear, step-by-step guide to processing diffusion-NMR data with GNAT, emphasizing best practices, quality control, and common pitfalls. The workflow covers data import, preprocessing (including baseline/phase considerations and signal selection), diffusion fitting and model choice, validation of results, and recommendations for reporting key parameters and uncertainty. Although written with new users in mind, this guide also serves as a reference for experienced practitioners seeking greater consistency and rigor in DOSY analysis. By promoting standardized, reproducible workflows and encouraging the use of open-source tools, this work aims to improve the transparency, quality, and comparability of diffusion-NMR studies.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 8","pages":"729-744"},"PeriodicalIF":2.1,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.70110","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147868508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NMR in Mexico and Central America","authors":"Armando Ariza-Castolo","doi":"10.1002/mrc.70116","DOIUrl":"10.1002/mrc.70116","url":null,"abstract":"&lt;p&gt;Mexico and Central America, including the Caribbean Islands, are a region located between 10° and 32° North latitude and 59° and 143° West longitude. This area has notable biodiversity, covering less than 2% of the Earth's land surface but hosting about 12% of its flora and fauna. Mexico is acknowledged as a megadiverse country. Central America contains about 7% of the world's animal and plant species, even though it represents only 0.5% of the world's territory. The Caribbean Islands have approximately 50% endemic plant life. For this reason, natural products are an important source of research and scientific work.&lt;/p&gt;&lt;p&gt;Nuclear Magnetic Resonance plays a central role in molecular structure elucidation due to its experimental and theoretical tools, which provide precise and reliable information. The information provided by this spectroscopy allows us to go beyond simple assignment and to understand the factors that influence the reported parameters. From structural interpretation using theoretical calculations to chemometric analysis by NMR, this technique constitutes a promising tool in biotechnology, as well as for the automatic analysis of complex mixtures.&lt;/p&gt;&lt;p&gt;Labeled compounds enable site-specific &lt;sup&gt;15&lt;/sup&gt;N detection of inhibitors in both solution and solid-state NMR experiments, which is useful for obtaining molecular-level insight into intermolecular interactions. One of the most relevant aspects of natural products is their biological properties, as illustrated by the antiprotozoal activity of the cyclopeptide papaucin, isolated from &lt;i&gt;Annona diversifolia&lt;/i&gt;.&lt;/p&gt;&lt;p&gt;In solid-state NMR, the technique has been used to determine the degree of substitution, chemical composition, and the dynamic and polymorphic properties of cellulose derivatives. Mexico has a long history of steroid research, going back more than one hundred years. Solid-state NMR has also been used to analyze the crystalline solvate structures of 5α-bromo-6β,19-epoxy-androstan-3β,17β-diol diacetate and to demonstrate the importance of noncovalent interactions in rotational barriers. Molecular dynamics have been studied in eugenol included in β-cyclodextrin using NMR relaxation rates, supported by experimental data and molecular dynamics simulations.&lt;/p&gt;&lt;p&gt;The reactivity of sugar acid derivatives, such as D-glycero-D-gulo-heptono-1,4-lactone, has been explored using different methodologies such as mechanochemical methods, thermal treatment, ultrasonic baths, and focused ultrasonication. NMR is a privileged methodology for evaluating reaction mechanisms and the efficiency of chemical transformations, as demonstrated in Kondrat'eva aza-Diels–Alder cycloadditions and in the synthetic utility of Ugi–Zhu 5-aminooxazole derivatives.&lt;/p&gt;&lt;p&gt;It is possible to relate the reactivity of chemical compounds to their relative acidity, which can be determined by NMR microtitration. An excellent interpretation is presented based on Baeyer and Pitzer strain, &lt;i&gt;syn&lt;/i&gt;-diaxial and ","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 8","pages":"709-710"},"PeriodicalIF":2.1,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.70116","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147816736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finely Pulverized Low-Moisture (FPL) Gel-State NMR for Near-Completely Solubilized Whole Plant Cell Walls","authors":"Hoon Kim,&nbsp;Yimin Mao,&nbsp;Daniel J. Yelle,&nbsp;Jorge Rencoret,&nbsp;José C. del Río,&nbsp;Peter Kitin","doi":"10.1002/mrc.70106","DOIUrl":"10.1002/mrc.70106","url":null,"abstract":"<div>\u0000 \u0000 <p>High-resolution NMR analysis of heterogeneous, insoluble lignocellulosic materials is a significant challenge because poor magnetic field homogeneity and restricted molecular mobility often hinder the acquisition of reproducible solution-state NMR spectra. In studies of lignocellulosic biomass and plant cell walls, gel-state NMR methods have enabled important advances. However, practical limitations in sample preparation, shimming stability, and spectral broadening have constrained method robustness and routine use. Here, we present a finely pulverized low-moisture (FPL) gel-state NMR method that enables the reliable acquisition of high-quality two-dimensional (2D) HSQC spectra from intact whole plant cell walls without chemical pretreatment. Systematic evaluation of drying protocols, ball-milling efficiency, and solvent composition shows that moisture control and particle fineness are the primary factors influencing gel homogeneity and magnetic field shimming performance. Use of a DMSO-<i>d₆</i>/DMF-<i>d₇</i> (4:1, v/v) solvent system produces gels with reproducible chemical shifts, narrow linewidths, and well-resolved heteronuclear correlations. This stability allows standard automated shimming and acquisition protocols to be applied reliably. The method is validated across diverse types of biomass, establishing a robust NMR sample-preparation framework for whole plant cell wall analysis and extending the practical reach of solution-state NMR methodologies.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 8","pages":"672-681"},"PeriodicalIF":2.1,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147699296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coumarin Dimers From Hydrangea davidii and Their Antimalarial Activities","authors":"Wan-Xian Qi,&nbsp;Wei-Juan Zu,&nbsp;Gang Li,&nbsp;Jing Wang,&nbsp;Li-Juan Lang,&nbsp;Rong Liu,&nbsp;Bei Jiang,&nbsp;Chao-Jiang Xiao","doi":"10.1002/mrc.70105","DOIUrl":"10.1002/mrc.70105","url":null,"abstract":"<div>\u0000 \u0000 <p>Two new coumarin dimers, hydradavins A and B (<b>1</b> and <b>2</b>), along with a coumarin-phenylpropanoid adduct (<b>3</b>), were isolated from the 95% EtOH extract of roots and stems of <i>Hydrangea davidii</i>. Their structures were determined by comprehensive analyses of the spectroscopic data and physicochemical properties. Hydradavins A and B (<b>1</b> and <b>2</b>) are the first examples of coumarin dimers from the genus <i>Hydrangea</i>. In addition, compound <b>3</b> exhibited significant in vitro antimalarial activity with IC₅₀ value of 1.7 ± 0.1 μM.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 7","pages":"616-620"},"PeriodicalIF":1.4,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147574564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing Numerical Approaches for the Analysis of 1H Nuclear Magnetic Relaxation Dispersion Profiles in Clay Suspensions","authors":"Zlanseu R. Tan,&nbsp;Natalie Malikova,&nbsp;Guillaume Mériguet,&nbsp;Laurent Michot,&nbsp;Jean-Pierre Korb,&nbsp;François Ribot,&nbsp;Pierre Levitz,&nbsp;Anne-Laure Rollet","doi":"10.1002/mrc.70097","DOIUrl":"10.1002/mrc.70097","url":null,"abstract":"<div>\u0000 \u0000 <p>Analyzing nuclear magnetic relaxation dispersion (NMRD) profiles to determine parameters of atomic/molecular motion in complex systems is a challenging task that involves the fitting of these profiles. The choice of the theoretical model, the constraint on parameters, and their reliability are key factors for a realistic description of systems. Herein, strategies for fitting proton NMRD profiles in smectite clay aqueous suspensions are evaluated, with the aim of providing the most realistic description of water molecules dynamics at clay surfaces. Profiles are adjusted with a combination of Jean-Pierre Korb (JPK) and Solomon-Bloembergen-Morgan (SBM) model. Due to the large number of parameters involved, rigorous methodology is implemented to achieve a unique and reliable solution. Two approaches are tested. In a one-step approach, the overall theoretical model (JPK + SBM) is adjusted to experimental profile at once. In a two-step approach, the frequency ranges where JPK and SBM models prevail, and an initial set of parameters obtained from the one-step approach serve as starting point for a segmented regression procedure. Below a frequency \u0000<span></span><math>\u0000 <msub>\u0000 <mrow>\u0000 <mi>ω</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>I</mi>\u0000 <mo>,</mo>\u0000 <mi>l</mi>\u0000 <mi>i</mi>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 </msub></math> chosen as the breakpoint, profiles are fitted with the JPK model (first step) and the resulting optimized parameters injected and kept constant in the global model (second step), to optimize the SBM parameters. The study is applied to montmorillonite and beidellite clay suspensions. While, for the former, both approaches lead to fairly similar and conclusive results, for the later, only the two-step approach provides a reasonable description of the system.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 7","pages":"641-654"},"PeriodicalIF":1.4,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147645755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of TEMPOL Radical on the Longitudinal NMR Relaxation in Ethylene Glycol: A Simple Controlled Model System","authors":"E. M. Erro,&nbsp;C. C. Fraenza,&nbsp;L. Gerbino,&nbsp;E. Anoardo","doi":"10.1002/mrc.70099","DOIUrl":"10.1002/mrc.70099","url":null,"abstract":"<div>\u0000 \u0000 <p>The presence of radicals in fluids can significantly influence the ¹H longitudinal nuclear magnetic resonance relaxation processes. The field-cycling nuclear magnetic relaxometry technique provides a unique approach to study these interactions within a broad Larmor frequency range. The situation is quite common in fluid systems subjected to oxidative stress, such as lubricants in internal combustion engines. Our previous studies in lubricant degradation did not consider in detail specific effects of radicals on the ¹H longitudinal relaxation. In the present work, we focus on a simplified system in which TEMPOL radicals are introduced in controlled concentrations into ethylene glycol samples. The system's behavior is evaluated at different radical concentrations to elucidate the influence of the paramagnetic species on the relaxation dispersion profile. We propose the inclusion of an additional relaxation term to account for intermolecular proton–electron interactions. We observe that, for radical concentrations exceeding approximately 2 × 10¹⁷ radicals/cm³, paramagnetic interactions dominate the relaxation dispersion at Larmor frequencies below 1 MHz. Moreover, we show that both the diffusion constants of ethylene glycol and TEMPOL molecules can be estimated from a single experiment. The consistency of our results with existing literature suggests an in-depth analysis of the paramagnetic contribution in the relaxometric characterization of degraded lubricants.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 7","pages":"608-615"},"PeriodicalIF":1.4,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147504286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MRI for Mixing Quality in Microfluidics","authors":"J. Götz,&nbsp;T. Rudszuck,&nbsp;L. Kontschak,&nbsp;T. Oerther,&nbsp;H. Nirschl,&nbsp;G. Guthausen","doi":"10.1002/mrc.70100","DOIUrl":"10.1002/mrc.70100","url":null,"abstract":"<p>Liquid state processes often involve mixing of process streams. With the development of microfluidics in chemical engineering, questions arise about analytical tools which are capable of monitoring the processes spatially and time-resolved. Optical techniques are widely spread, which, however, require optical transparency. MRI techniques are explored to elucidate the possibilities of measuring hydrodynamic parameters and monitoring mixing with molecular, chemical information.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 7","pages":"600-607"},"PeriodicalIF":1.4,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.70100","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147499374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LowCOST-HSQC Variants for Fast-Pulsing High ω1-Resolved 2D Experiments","authors":"David Schulze-Sünninghausen,&nbsp;Johanna Becker,&nbsp;Martin R. M. Koos,&nbsp;Burkhard Luy","doi":"10.1002/mrc.70102","DOIUrl":"10.1002/mrc.70102","url":null,"abstract":"<p>The LowCOST-HSQC is a sensitivity-enhanced HSQC version that retains unused proton polarization for subsequent scans in correlations to low natural abundance nuclei like \u0000<span></span><math>\u0000 <msup>\u0000 <mrow></mrow>\u0000 <mrow>\u0000 <mn>13</mn>\u0000 </mrow>\u0000 </msup></math>C or \u0000<span></span><math>\u0000 <msup>\u0000 <mrow></mrow>\u0000 <mrow>\u0000 <mn>15</mn>\u0000 </mrow>\u0000 </msup></math>N. Together with fast polarization distribution via isotropic mixing, it allows the acquisition of fast-pulsing 2D experiments. We give a detailed introduction and comparison of three possible INEPT-type transfer elements for the LowCOST approach—the original LowCOST, the ZIP, and a specific TIG-BIRD element—and evaluate various variants of the LowCOST-HSQC.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 7","pages":"655-665"},"PeriodicalIF":1.4,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.70102","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147699307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NMR-Based Metabolomics Profiling Reveals Dose-Dependent Cardiotoxic Effects of Favipiravir in Rats","authors":"Ali Erdoğan,&nbsp;Akın Mumcu,&nbsp;Zeynep Rozerin Çevik,&nbsp;Ömer Lütfi Özkan,&nbsp;Berat Doğan","doi":"10.1002/mrc.70104","DOIUrl":"10.1002/mrc.70104","url":null,"abstract":"<div>\u0000 \u0000 <p>Metabolomics is a powerful tool for assessing drug safety and understanding the biochemical effects of pharmaceutical compounds. Favipiravir, a drug widely used during the COVID-19 pandemic, has been associated with damage to various organs, including the heart. However, a comprehensive analysis of its metabolic impact on cardiac tissue has not yet been performed. This study utilized high-resolution ¹H NMR-based metabolomics to investigate metabolic alterations in rat heart tissue following favipiravir treatment. For this purpose, 60 male Wistar Albino rats were randomly assigned to three groups: control, low-dose favipiravir (200 mg/kg), and high-dose favipiravir (300 mg/kg), with 20 rats in each group. Treatments were administered via oral gavage, and heart tissue samples were collected for ¹H NMR analysis after the treatment period. Bioinformatics analysis results showed significant dose-dependent changes in key metabolites in the favipiravir-treated groups. Decreased levels of ATP, citrate, and valine accompanied by increased levels of lactate and AMP suggest a disruption in mitochondrial energy production and a shift towards anaerobic glycolysis. At the higher dose, more pronounced disruptions were noted, including decreases in glutamate, glutamine, aspartate, tyrosine, 3-methylhistidine, and asparagine, suggesting a broader metabolic dysfunction. These findings offer valuable insights into the cardiotoxic effects of favipiravir and highlight the utility of NMR metabolomics in identifying drug-induced metabolic disturbances.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"64 7","pages":"629-640"},"PeriodicalIF":1.4,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147623196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}