Magnetic Resonance in Chemistry最新文献

{"title":"Non-uniform sampling to enhance the performance of compact NMR for characterizing new psychoactive substances","authors":"Thomas Castaing-Cordier,&nbsp;Sélina Crasnier,&nbsp;Damien Dubois,&nbsp;Virginie Ladroue,&nbsp;Audrey Buleté,&nbsp;Cédric Prudhomme,&nbsp;Céline Charvoz,&nbsp;Fabrice Besacier,&nbsp;Denis Jacquemin,&nbsp;Patrick Giraudeau,&nbsp;Jonathan Farjon","doi":"10.1002/mrc.5416","DOIUrl":"10.1002/mrc.5416","url":null,"abstract":"<p>Efficient and robust analytical methods are needed to improve the identification and subsequent regulation of new psychoactive substances (NPS). NMR spectroscopy is a unique method able to determine the structure of small molecules such as NPS even in mixtures. However, high-field NMR analysis is associated with expensive purchase and maintenance costs. For more than a decade, compact NMR spectrometers have changed this paradigm. It was recently shown that a dedicated analytical workflow combining compact NMR and databases could identify the molecular structure of NPS, in spite of the lower spectral dispersion and sensitivity of compact spectrometers. This approach relies on ¹H-¹³C HSQC to both recognize NPS and elucidate the structure of unknown substances. Still, its performance is limited by the need to compromise between resolution and experiment time. Here, we show that this strategy can be significantly improved by implementing non-uniform sampling (NUS) to improve spectral resolution in the ¹³C dimension of HSQC at no cost in terms of experiment time. Gains in the range of 3 to 4 in resolution are achieved for pure NPS and for a mixture. Finally, 2D HSQC with NUS was applied to improve the identification of NPS with the assistance of databases. The resulting method appears as a useful tool for the characterization of NPS in mixtures, which is essential for forensic laboratories.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 5","pages":"378-385"},"PeriodicalIF":2.0,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5416","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138295479","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":"To flame-seal or not to flame-seal NMR tubes: The role of liquid–vapor equilibria on the accuracy of variable temperature experiments","authors":"Derek Morrelli,&nbsp;Santanu Maitra,&nbsp;V. V. Krishnan","doi":"10.1002/mrc.5411","DOIUrl":"10.1002/mrc.5411","url":null,"abstract":"<p>In NMR experiments, it is crucial to control the temperature of the sample, especially when measuring kinetic parameters. Usually, it takes 2 to 5 min for the temperature of the sample inside the NMR probe to stabilize at a fixed value set for the experiment. However, the NMR sample tubes are flame-sealed in some cases, such as when working with volatile solvents, atmosphere-sensitive samples, or calibration samples for long-term use. When these samples are placed inside the NMR probe, the spectrometer controls the lower portion (liquid phase) of the NMR sample tube with a gas flow at a fixed temperature, while the upper portion (vapor) is at ambient temperature. This probe design creates a unique temperature gradient across the sample, leading to vapor pressure build-up, particularly inside a sealed NMR tube. By analyzing the temperature-dependent spectral line shape changes of a chemical exchange process, we report that under standard experimental conditions, the sample temperature can take up to 2 to 3 h (instead of minutes) to stabilize. The time scale of the liquid–vapor equilibrium process is much slower, with a half-life exceeding 35 min, in contrast to the 2-min duration required to obtain each spectrum. This phenomenon is exclusively due to the liquid–vapor equilibrium process of the flame-sealed NMR tube and is not observable otherwise.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 1","pages":"19-27"},"PeriodicalIF":2.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138295480","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":"Frontiers in NMR metabolomics","authors":"G. A. Nagana Gowda,&nbsp;Robert Powers","doi":"10.1002/mrc.5400","DOIUrl":"10.1002/mrc.5400","url":null,"abstract":"","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 12","pages":"627"},"PeriodicalIF":2.0,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138176531","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":"13C-depleted algae as food: Permitting background free in-vivo nuclear magnetic resonance of Daphnia magna at natural abundance","authors":"William W. Wolff,&nbsp;Jacob Pellizzari,&nbsp;Ronald Soong,&nbsp;Daniel H. Lysak,&nbsp;Katrina Steiner,&nbsp;Kiera Ronda,&nbsp;Peter Costa,&nbsp;Katelyn Downey,&nbsp;Vincent Moxley-Paquette,&nbsp;Chris Suszczynski,&nbsp;Steven Boehmer,&nbsp;Jacob R. Prat,&nbsp;Andre J. Simpson","doi":"10.1002/mrc.5409","DOIUrl":"10.1002/mrc.5409","url":null,"abstract":"<p>\u0000 \u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 1","pages":"11-18"},"PeriodicalIF":2.0,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138176529","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":"Permethylation as a strategy for high-molecular-weight polysaccharide structure analysis by nuclear magnetic resonance—Case study of Xylella fastidiosa extracellular polysaccharide","authors":"Ikenna E. Ndukwe,&nbsp;Ian Black,&nbsp;Claudia A. Castro,&nbsp;Jiri Vlach,&nbsp;Christian Heiss,&nbsp;Caroline Roper,&nbsp;Parastoo Azadi","doi":"10.1002/mrc.5413","DOIUrl":"10.1002/mrc.5413","url":null,"abstract":"<p>Current practices for structural analysis of extremely large-molecular-weight polysaccharides via solution-state nuclear magnetic resonance (NMR) spectroscopy incorporate partial depolymerization protocols that enable polysaccharide solubilization in suitable solvents. Non-specific depolymerization techniques utilized for glycosidic bond cleavage, such as chemical degradation or ultrasonication, potentially generate structural fragments that can complicate complete and accurate characterization of polysaccharide structures. Utilization of appropriate enzymes for polysaccharide degradation, on the other hand, requires prior structural knowledge and optimal enzyme activity conditions that are not available to an analyst working with novel or unknown compounds. Herein, we describe an application of a permethylation strategy that allows the complete dissolution of intact polysaccharides for NMR structural characterization. This approach is utilized for NMR analysis of <i>Xylella fastidiosa</i> extracellular polysaccharide (EPS), which is essential for the virulence of the plant pathogen that affects multiple commercial crops and is responsible for multibillion dollar losses each year.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 5","pages":"370-377"},"PeriodicalIF":2.0,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5413","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138176530","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":"Theoretical studies on the local structure and spin Hamiltonian parameters for Cu2+ ions in LiTaO3 crystal","authors":"Yun Chen,&nbsp;Lu Tang,&nbsp;Houdao Cai,&nbsp;Meiyun Zhang,&nbsp;Xunjie Wang,&nbsp;Cuidi Feng,&nbsp;Wenbo Xiao,&nbsp;Huaming Zhang","doi":"10.1002/mrc.5414","DOIUrl":"10.1002/mrc.5414","url":null,"abstract":"<p>The local structure and spin Hamiltonian parameters (SHPs) <i>g</i> factors (<i>g</i>_<i>x</i>, <i>g</i>_<i>y</i>, <i>g</i>_<i>z</i>) and the hyperfine structure constants (<i>A</i>_<i>x</i>, <i>A</i>_<i>y</i>, <i>A</i>_<i>z</i>) for Cu²⁺ doped in the LiTaO₃ crystal are theoretically investigated by the perturbation formulas for a 3d⁹ ion under rhombically elongated octahedral based on the cluster approach. The impurity Cu²⁺ was assumed to occupy the host trigonally-distorted octahedral Li⁺ site and experience the Jahn–Teller (JT) distortion from the host trigonal octahedral [TaO₆]¹⁰⁻ to the impurity rhombically elongated octahedral [CuO₆]¹⁰⁻. Based on the calculations, the impurity-ligand bond lengths parallel and perpendicular to the <i>C</i>₂-axis are found to be <i>R</i>_||(≈ 2.305 Å) and <i>R</i>_⊥ (≈ 2.112 Å) for the studied [CuO₆]¹⁰⁻ cluster, with the planar bond angle θ (≈ 78.2°). Meanwhile, the ground-state wave function for Cu²⁺ center in LiTaO₃ was also obtained. The calculated SHPs based on the above local lattice distortions agree well with the experimental data, and the results are discussed.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 1","pages":"28-36"},"PeriodicalIF":2.0,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136398087","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":"Solid-state 35/37Cl NMR detection of chlorine atoms directly bound to paramagnetic cobalt(II) ions in powder samples","authors":"Lukas Bauder,&nbsp;Gang Wu","doi":"10.1002/mrc.5407","DOIUrl":"10.1002/mrc.5407","url":null,"abstract":"<p>We report high-quality solid-state ^35/37Cl NMR spectra for chlorine atoms directly bonded to paramagnetic cobalt(II) ions (high spin <i>S</i> = 3/2) in powered samples of CoCl₂, CoCl₂·2H₂O, CoCl₂·6H₂O, and CoCl₂(terpy) (terpy = 2,2′:6′,2″-terpyridine). Because solid-state ^35/37Cl NMR spectra for paramagnetic cobalt(II) compounds often cover an extremely wide spectral range, they were recorded in this work in the form of variable-offset cumulative spectra. Solid-state ^35/37Cl NMR measurements were performed at three magnetic fields (11.7, 14.1, and 16.5 T) and analysis of data yielded information about ^35/37Cl quadrupole coupling and hyperfine coupling tensors in these paramagnetic cobalt(II) compounds. Experimental ^35/37Cl NMR tensors were found to be in reasonable agreement with quantum chemical calculations based on a periodic DFT method implemented in BAND.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 3","pages":"145-155"},"PeriodicalIF":2.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5407","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72209861","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":"Can simple ‘molecular’ corrections outperform projector augmented-wave density functional theory in the prediction of 35Cl electric field gradient tensor parameters for chlorine-containing crystalline systems?","authors":"Cory M. Widdifield,&nbsp;Fatemeh Zakeri","doi":"10.1002/mrc.5408","DOIUrl":"10.1002/mrc.5408","url":null,"abstract":"<p>Many-body expansion (MBE) fragment approaches have been applied to accurately compute nuclear magnetic resonance (NMR) parameters in crystalline systems. Recent examples demonstrate that electric field gradient (EFG) tensor parameters can be accurately calculated for ¹⁴N and ¹⁷O. A key additional development is the simple molecular correction (SMC) approach, which uses two one-body fragment (i.e., isolated molecule) calculations to adjust NMR parameter values established using ‘benchmark’ projector augmented-wave (PAW) density functional theory (DFT) values. Here, we apply a SMC using the hybrid PBE0 exchange-correlation (XC) functional to see if this can improve the accuracy of calculated ³⁵Cl EFG tensor parameters. We selected eight organic and two inorganic crystal structures and considered 15 chlorine sites. We find that this SMC improves the accuracy of computed values for both the ³⁵Cl quadrupolar coupling constant (<i>C</i>_Q) and the asymmetry parameter (\u0000<math>\u0000 <msub>\u0000 <mi>η</mi>\u0000 <mi>Q</mi>\u0000 </msub></math>) by approximately 30% compared with benchmark PAW DFT values. We also assessed a SMC that offers local improvements not only in terms of the quality of the XC functional but simultaneously in the quality of the description of relativistic effects <i>via</i> the inclusion of spin–orbit effects. As the inorganic systems considered contain heavy atoms bonded to the chlorine atoms, we find further improvements in the accuracy of calculated ³⁵Cl EFG tensor parameters when both a hybrid functional and spin–orbit effects are included in the SMC. On the contrary, for chlorine-containing organics, the inclusion of spin–orbit relativistic effects using a SMC does not improve the accuracy of computed ³⁵Cl EFG tensor parameters.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 3","pages":"156-168"},"PeriodicalIF":2.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5408","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89718819","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":"6aH-Benzo[α]fluorene: NMR evidence of the unexpected product of the reaction of butyryl chloride with 1,2-diphenylacetylene","authors":"Sergey V. Zinchenko,&nbsp;Valentina A. Kobelevskaya,&nbsp;Alexander V. Popov","doi":"10.1002/mrc.5406","DOIUrl":"10.1002/mrc.5406","url":null,"abstract":"<p>The reaction of butyryl chloride with ethynylbenzene in the presence of AlCl₃ afforded a mixture of the Z/E-isomers of 1-chloro-2-phenylhex-1-en-3-one. 1,2-Diphenylethyne under these conditions gave a novel polycarbocycle core, 6a<i>H</i>-benzo[<i>a</i>]fluorene. The chemical structure of 11-chloro-5,6-diphenyl-6a-propyl-6a<i>H</i>-benzo[<i>a</i>]fluorene was established by means of IE-MS, ¹H, ¹³C NMR, COSY, HSQC, HMBC, and 2D INADEQUATE technique.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 1","pages":"61-68"},"PeriodicalIF":2.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71483236","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":"The effect of tube quality on externally calibrated quantitative nuclear magnetic resonance analysis: How bad can it be?","authors":"Jessica L. Ochoa,&nbsp;Stephan Germann,&nbsp;Breanna Conklin,&nbsp;Kenji Kurita,&nbsp;David J. Russell,&nbsp;Cassie Yang,&nbsp;José G. Napolitano","doi":"10.1002/mrc.5404","DOIUrl":"10.1002/mrc.5404","url":null,"abstract":"<p>Externally calibrated quantitative nuclear magnetic resonance (NMR) approaches offer practical means to simultaneously evaluate chemical identity and content without the addition of calibrants to the test sample. Despite continuous advances in external calibration over the last few decades, adoption of these approaches has been slower than expected. Variations in NMR tube geometry are a commonly overlooked factor that can have a substantial effect on externally calibrated quantitation methods. In this report, we investigate the extent to which tube-to-tube volume variability can affect quantitative NMR outcomes. The results highlight the importance of considering tube quality during the development stages of externally calibrated quantitative methods. In addition, we propose a simple, yet effective volume correction strategy using the residual protonated solvent signal that, based on experiments with mixed NMR tubes of varying quality, alleviates the effect of tube-to-tube variability.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 1","pages":"4-10"},"PeriodicalIF":2.0,"publicationDate":"2023-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71483237","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}