Magnetic Resonance in Chemistry最新文献_第7页

Twenty years of nmrshiftdb2: A case study of an open database for analytical chemistry nmrshiftdb2二十年：分析化学开放数据库案例研究。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-12-19 DOI: 10.1002/mrc.5418

Stefan Kuhn, Heinz Kolshorn, Christoph Steinbeck, Nils Schlörer

引用次数: 0

Predicting 51V nuclear magnetic resonance observables in molecular crystals 预测分子晶体中的 51 V 核磁共振观测值。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-12-19 DOI: 10.1002/mrc.5420

Joshua D. Hartman, Daniel Capistran

{"title":"Predicting 51V nuclear magnetic resonance observables in molecular crystals","authors":"Joshua D. Hartman, Daniel Capistran","doi":"10.1002/mrc.5420","DOIUrl":"10.1002/mrc.5420","url":null,"abstract":"Solid-state nuclear magnetic resonance (NMR) spectroscopy and quantum chemical density functional theory (DFT) calculations are widely used to characterize vanadium centers in biological and pharmaceutically relevant compounds. Several techniques have been recently developed to improve the accuracy of predicted NMR parameters obtained from DFT. Fragment-based and planewave-corrected methods employing hybrid density functionals are particularly effective tools for solid-state applications. A recent benchmark study involving molecular crystal compounds found that fragment-based NMR calculations using hybrid density functionals improve the accuracy of predicted 51V chemical shieldings by 20% relative to traditional planewave methods. This work extends the previous study, including a careful analysis of 51V chemical shift anisotropy, electric field gradient calculations, and a more extensive test set. The accuracy of planewave-corrected techniques and recently developed fragment-based methods using electrostatic embedding based on the polarized continuum model (PCM) are found to be highly competitive with previous methods. Planewave-corrected methods achieve a 34% improvement in the errors of predicted 51V chemical shieldings relative to planewave. Additionally, planewave-corrected and fragment-based calculations were performed using PCM embedding, improving the accuracy of predicted 51V chemical shielding (CS) tensor principal values by 30% and \u0000<math>\u0000 <msub>\u0000 <mrow>\u0000 <mi>C</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>q</mi>\u0000 </mrow>\u0000 </msub></math> values by 15% relative to traditional planewave methods. The performance of these methods is further examined using a redox-active oxovandium complex and a common 51V NMR reference compound.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5420","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138799984","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}

引用次数: 0

Polarization transfer methods for quantitative analysis of flowing mixtures with benchtop 13C NMR spectroscopy 利用台式 13 C NMR 光谱定量分析流动混合物的极化转移方法。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-12-19 DOI: 10.1002/mrc.5417

Johnnie Phuong, Zeno Romero, Hans Hasse, Kerstin Münnemann

{"title":"Polarization transfer methods for quantitative analysis of flowing mixtures with benchtop 13C NMR spectroscopy","authors":"Johnnie Phuong, Zeno Romero, Hans Hasse, Kerstin Münnemann","doi":"10.1002/mrc.5417","DOIUrl":"10.1002/mrc.5417","url":null,"abstract":"Benchtop NMR spectroscopy is attractive for process monitoring; however, there are still drawbacks that often hamper its use, namely, the comparatively low spectral resolution in 1H NMR, as well as the low signal intensities and problems with the premagnetization of flowing samples in 13C NMR. We show here that all these problems can be overcome by using 1H-13C polarization transfer methods. Two ternary test mixtures (one with overlapping peaks in the 1H NMR spectrum and one with well-separated peaks, which was used as a reference) were studied with a 1 T benchtop NMR spectrometer using the polarization transfer sequence PENDANT (polarization enhancement that is nurtured during attached nucleus testing). The mixtures were analyzed quantitatively in stationary as well as in flow experiments by PENDANT enhanced 13C NMR experiments, and the results were compared with those from the gravimetric sample preparation and from standard 1H and 13C NMR spectroscopy. Furthermore, as a proxy for a process monitoring application, continuous dilution experiments were carried out, and the composition of the mixture was monitored in a flow setup by 13C NMR benchtop spectroscopy with PENDANT. The results demonstrate the high potential of polarization transfer methods for applications in quantitative process analysis with benchtop NMR instruments, in particular with flowing samples.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5417","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138799997","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}

引用次数: 0

Intracellular pyruvate–lactate–alanine cycling detected using real-time nuclear magnetic resonance spectroscopy of live cells and isolated mitochondria 利用活细胞和分离线粒体的实时核磁共振光谱检测细胞内丙酮酸-乳酸-丙氨酸循环

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-12-14 DOI: 10.1002/mrc.5419

G. A. Nagana Gowda, John A. Lusk, Vadim Pascua

{"title":"Intracellular pyruvate–lactate–alanine cycling detected using real-time nuclear magnetic resonance spectroscopy of live cells and isolated mitochondria","authors":"G. A. Nagana Gowda, John A. Lusk, Vadim Pascua","doi":"10.1002/mrc.5419","DOIUrl":"10.1002/mrc.5419","url":null,"abstract":"Pyruvate, an end product of glycolysis, is a master fuel for cellular energy. A portion of cytosolic pyruvate is transported into mitochondria, while the remaining portion is converted reversibly into lactate and alanine. It is suggested that cytosolic lactate and alanine are transported and metabolized inside mitochondria. However, such a mechanism continues to be a topic of intense debate and investigation. As a part of gaining insight into the metabolic fate of the cytosolic lactate and alanine; in this study, the metabolism of mouse skeletal myoblast cells (C2C12) and their isolated mitochondria was probed utilizing stable isotope-labeled forms of the three glycolysis products, viz. [3-13C1]pyruvate, [3-13C1]lactate, and [3-13C1]alanine, as substrates. The uptake and metabolism of each substrate was monitored, separately, in real-time using 1H-13C 2D nuclear magnetic resonance (NMR) spectroscopy. The dynamic variation of the levels of the substrates and their metabolic products were quantitated as a function of time. The results demonstrate that all three substrates were transported into mitochondria, and each substrate was metabolized to form the other two metabolites, reversibly. These results provide direct evidence for intracellular pyruvate–lactate–alanine cycling, in which lactate and alanine produced by the cytosolic pyruvate are transported into mitochondria and converted back to pyruvate. Such a mechanism suggests a role for lactate and alanine to replenish mitochondrial pyruvate, the primary source for adenosine triphosphate (ATP) synthesis through oxidative phosphorylation and the electron transport chain. The results highlight the potential of real-time NMR spectroscopy for gaining new insights into cellular and subcellular functions.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138688904","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}

引用次数: 0

PDSFit: PDS data analysis in the presence of orientation selectivity, g-anisotropy, and exchange coupling PDSFit：存在取向选择性、g-各向异性和交换耦合时的 PDS 数据分析

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-12-12 DOI: 10.1002/mrc.5415

Dinar Abdullin, Pablo Rauh Corro, Tobias Hett, Olav Schiemann

{"title":"PDSFit: PDS data analysis in the presence of orientation selectivity, g-anisotropy, and exchange coupling","authors":"Dinar Abdullin, Pablo Rauh Corro, Tobias Hett, Olav Schiemann","doi":"10.1002/mrc.5415","DOIUrl":"10.1002/mrc.5415","url":null,"abstract":"Pulsed dipolar electron paramagnetic resonance spectroscopy (PDS), encompassing techniques such as pulsed electron–electron double resonance (PELDOR or DEER) and relaxation-induced dipolar modulation enhancement (RIDME), is a valuable method in structural biology and materials science for obtaining nanometer-scale distance distributions between electron spin centers. An important aspect of PDS is the extraction of distance distributions from the measured time traces. Most software used for this PDS data analysis relies on simplifying assumptions, such as assuming isotropic g-factors of ~2 and neglecting orientation selectivity and exchange coupling. Here, the program PDSFit is introduced, which enables the analysis of PELDOR and RIDME time traces with or without orientation selectivity. It can be applied to spin systems consisting of up to two spin centers with anisotropic g-factors and to spin systems with exchange coupling. It employs a model-based fitting of the time traces using parametrized distance and angular distributions, and parametrized PDS background functions. The fitting procedure is followed by an error analysis for the optimized parameters of the distributions and backgrounds. Using five different experimental data sets published previously, the performance of PDSFit is tested and found to provide reliable solutions.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5415","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138689011","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}

引用次数: 0

Determination of self-diffusion coefficients in mixtures with benchtop 13C NMR spectroscopy via polarization transfer 偏振转移台式13c核磁共振光谱法测定混合物自扩散系数。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-11-28 DOI: 10.1002/mrc.5412

Johnnie Phuong, Sarah Mross, Daniel Bellaire, Hans Hasse, Kerstin Münnemann

{"title":"Determination of self-diffusion coefficients in mixtures with benchtop 13C NMR spectroscopy via polarization transfer","authors":"Johnnie Phuong, Sarah Mross, Daniel Bellaire, Hans Hasse, Kerstin Münnemann","doi":"10.1002/mrc.5412","DOIUrl":"10.1002/mrc.5412","url":null,"abstract":"Nuclear magnetic resonance (NMR) is an established method to determine self-diffusion coefficients in liquids with high precision. The development of benchtop NMR spectrometers makes the method accessible to a wider community. In most cases, 1H NMR spectroscopy is used to determine self-diffusion coefficients due to its high sensitivity. However, especially when using benchtop NMR spectrometers for the investigation of complex mixtures, the signals in 1H NMR spectra can overlap, hindering the precise determination of self-diffusion coefficients. In 13C NMR spectroscopy, the signals of different compounds are generally well resolved. However, the sensitivity of 13C NMR is significantly lower than that of 1H NMR spectroscopy leading to very long measurement times, which makes diffusion coefficient measurements based on 13C NMR practically infeasible with benchtop NMR spectrometers. To circumvent this problem, we have combined two known pulse sequences, one for polarization transfer from 1H to the 13C nuclei (PENDANT) and one for the measurement of diffusion coefficients (PFG). The new method (PENPFG) was used to measure the self-diffusion coefficients of three pure solvents (acetonitrile, ethanol and 1-propanol) as well as in all their binary mixtures and the ternary mixture at various compositions. For comparison, also measurements of the same systems were carried out with a standard PFG-NMR routine on a high-field NMR instrument. The results are in good agreement and show that PENPFG is a useful tool for the measurement of the absolute value of the self-diffusion coefficients in complex liquid mixtures with benchtop NMR spectrometers.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5412","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138445255","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}

引用次数: 0

Non-uniform sampling to enhance the performance of compact NMR for characterizing new psychoactive substances 非均匀取样，以提高紧凑核磁共振表征新的精神活性物质的性能。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-11-23 DOI: 10.1002/mrc.5416

Thomas Castaing-Cordier, Sélina Crasnier, Damien Dubois, Virginie Ladroue, Audrey Buleté, Cédric Prudhomme, Céline Charvoz, Fabrice Besacier, Denis Jacquemin, Patrick Giraudeau, Jonathan Farjon

{"title":"Non-uniform sampling to enhance the performance of compact NMR for characterizing new psychoactive substances","authors":"Thomas Castaing-Cordier, Sélina Crasnier, Damien Dubois, Virginie Ladroue, Audrey Buleté, Cédric Prudhomme, Céline Charvoz, Fabrice Besacier, Denis Jacquemin, Patrick Giraudeau, Jonathan Farjon","doi":"10.1002/mrc.5416","DOIUrl":"10.1002/mrc.5416","url":null,"abstract":"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.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"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}

引用次数: 0

To flame-seal or not to flame-seal NMR tubes: The role of liquid–vapor equilibria on the accuracy of variable temperature experiments 采用火焰密封或不采用火焰密封核磁共振管:汽液平衡对变温实验精度的影响。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-11-22 DOI: 10.1002/mrc.5411

Derek Morrelli, Santanu Maitra, V. V. Krishnan

{"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, Santanu Maitra, V. V. Krishnan","doi":"10.1002/mrc.5411","DOIUrl":"10.1002/mrc.5411","url":null,"abstract":"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.","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"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}

引用次数: 0

Frontiers in NMR metabolomics 核磁共振代谢组学前沿。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-11-21 DOI: 10.1002/mrc.5400

G. A. Nagana Gowda, Robert Powers

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13C-depleted algae as food: Permitting background free in-vivo nuclear magnetic resonance of Daphnia magna at natural abundance 作为食物的贫碳藻类:允许大水蚤在自然丰度下的无背景核磁共振。

IF 2 3区化学

Magnetic Resonance in Chemistry Pub Date : 2023-11-20 DOI: 10.1002/mrc.5409

William W. Wolff, Jacob Pellizzari, Ronald Soong, Daniel H. Lysak, Katrina Steiner, Kiera Ronda, Peter Costa, Katelyn Downey, Vincent Moxley-Paquette, Chris Suszczynski, Steven Boehmer, Jacob R. Prat, Andre J. Simpson

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