Solid state nuclear magnetic resonance最新文献

{"title":"High-quality 13C-detected structural analysis of mass-limited amyloid samples using a CPMAS CryoProbe and moderate magnetic fields","authors":"Sara Andrés-Campos ,&nbsp;Gustavo A. Titaux-Delgado ,&nbsp;Fátima C. Escobedo-González,&nbsp;Miguel Mompeán","doi":"10.1016/j.ssnmr.2025.102028","DOIUrl":"10.1016/j.ssnmr.2025.102028","url":null,"abstract":"<div><div>Solid-state NMR (SSNMR) of biomolecules typically requires several milligrams of sample to achieve sufficient sensitivity for multidimensional experiments, especially when relying on ¹³C detection. Recent developments in fast magic-angle spinning (MAS) and ¹H-detected methods have enabled the use of submilligram samples in reduced-diameter rotors, but these approaches demand advanced hardware and often suffer from limited ¹H chemical shift dispersion. Here, we demonstrate that a CPMAS CryoProbe enables the acquisition of high-quality ¹³C-detected 2D and 3D spectra from just ∼1.5 mg of uniformly labeled amyloid fibrils packed in a standard 3.2 mm rotor. As a proof of concept, we apply this approach to RIPK3, a key protein in immune signaling that forms functional amyloid assemblies. Using standard 3D experiments (NCACX and NCOCX), we obtain ¹³C and ¹⁵N backbone assignments and secondary structure information, despite the limited sample quantity and the use of only moderate magnetic fields. These findings highlight the potential of CPMAS CryoProbes to shift the paradigm in mass-limited SSNMR studies, from relying exclusively on ¹H-detection and fast MAS to reembracing ¹³C-detected strategies.</div></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"139 ","pages":"Article 102028"},"PeriodicalIF":1.8,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656609","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":"Experimental and Computational 17O Solid-State NMR Investigation of Na- and K-(Bi)carbonate Salts","authors":"Austin Peach, Nicolas Fabregue, David Gajan, Frédéric Mentink-Vigier, Faith Scott, Christel Gervais, Danielle Laurencin","doi":"10.1016/j.ssnmr.2025.102020","DOIUrl":"https://doi.org/10.1016/j.ssnmr.2025.102020","url":null,"abstract":"The importance of (bi)carbonate salts cannot be understated. They are vital to the Earth’s geology and ecosystems and are used as precursors by chemists for the synthesis of functional materials. Naturally, solid-state NMR (ssNMR) appears as the spectroscopic tool of choice to probe the atomic-level structure and dynamics of (bi)carbonate salts. Of the possible nuclei available as spectroscopic probes in carbonate and bicarbonate ions (<ce:italic>i.e.</ce:italic>, <ce:sup loc=\"pre\">1</ce:sup>H, <ce:sup loc=\"pre\">13</ce:sup>C, and <ce:sup loc=\"pre\">17</ce:sup>O), oxygen-17 is highly attractive. Yet, it is seldom employed, largely due to its low natural abundance (0.04%) and lack of practical enrichment protocols. Recently, we reported an effective <ce:sup loc=\"pre\">17</ce:sup>O-labeling strategy involving mechanochemistry of Na<ce:inf loc=\"post\">2</ce:inf>CO<ce:inf loc=\"post\">3</ce:inf>·H<ce:inf loc=\"post\">2</ce:inf>O, Na<ce:inf loc=\"post\">2</ce:inf>CO<ce:inf loc=\"post\">3</ce:inf>, NaHCO<ce:inf loc=\"post\">3</ce:inf>, K<ce:inf loc=\"post\">2</ce:inf>CO<ce:inf loc=\"post\">3</ce:inf>·1.5H<ce:inf loc=\"post\">2</ce:inf>O, and KHCO<ce:inf loc=\"post\">3</ce:inf>, and recorded their <ce:sup loc=\"pre\">17</ce:sup>O NMR spectral fingerprints near room temperature. In this work, ultra-low temperature (<ce:italic>i.e.</ce:italic>, 100 K) <ce:sup loc=\"pre\">17</ce:sup>O ssNMR spectra of these phases are acquired at two magnetic fields, 14.1 and 18.8 T, to extract the <ce:sup loc=\"pre\">17</ce:sup>O NMR parameters δ<ce:inf loc=\"post\">iso</ce:inf>, <ce:italic>C</ce:italic><ce:inf loc=\"post\">Q</ce:inf>, and η<ce:inf loc=\"post\">Q</ce:inf> for the different oxygen sites, and to further study the influence of dynamics on the spectra. We compare the experimental <ce:sup loc=\"pre\">17</ce:sup>O NMR parameters to those computed with GIPAW-DFT calculations both on static models, and after averaging by molecular dynamics (MD) simulations. This approach was taken to aid in analyzing the structure-spectra relationships and shed light on the dynamics. Lastly, we report the static GIPAW-DFT calculations of <ce:sup loc=\"pre\">17</ce:sup>O NMR parameters for a series of other carbonate salts of interest, further expanding upon current experimental <ce:sup loc=\"pre\">17</ce:sup>O ssNMR results.","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"151 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144621830","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":"Diverging errors: A comparison of DFT and machine-learning predictions of NMR shieldings","authors":"Ema Chaloupecká ,&nbsp;Ondřej Socha ,&nbsp;Martin Dračínský","doi":"10.1016/j.ssnmr.2025.102019","DOIUrl":"10.1016/j.ssnmr.2025.102019","url":null,"abstract":"<div><div>Accurate prediction of NMR parameters from first principles is essential for the structural characterization of molecular solids. Recent studies have shown that single-molecule correction schemes—based on hybrid DFT calculations—can significantly improve the accuracy of periodic DFT predictions of nuclear shieldings. Here, we evaluate the performance of this correction approach not only for periodic DFT calculations but also for ShiftML2, a machine-learning model trained on PBE-calculated NMR data. For ¹³C nuclei, the application of single-molecule PBE0 corrections to periodic PBE shieldings has reduced the root-mean-square deviation (RMSD) from 2.18 to 1.20 ppm, with negligible improvement observed for ¹H. When applied to ShiftML2 predictions, the corrections have yielded a smaller reduction in ¹³C RMSD (from 3.02 to 2.51 ppm); again, they have had minimal impact on ¹H predictions. Residual analysis has revealed weak correlation between DFT and ML errors, suggesting that while some sources of systematic deviation may be shared, others are likely distinct. These results demonstrate that DFT-specific correction schemes do not straightforwardly translate to machine-learning models, highlighting the need for ML-tailored post-processing or retraining strategies. The findings have important implications for the integration of machine learning into high-throughput NMR workflows and the development of more accurate predictive tools for solid-state spectroscopy.</div></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"138 ","pages":"Article 102019"},"PeriodicalIF":1.8,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514240","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":"A solid-state NMR approach for distinguishing between RNH2 and RNH3+ sites","authors":"Riley Nickles ,&nbsp;Emily C. Heider ,&nbsp;James K. Harper","doi":"10.1016/j.ssnmr.2025.102018","DOIUrl":"10.1016/j.ssnmr.2025.102018","url":null,"abstract":"<div><div>A necessary step in characterizing solid-phase organic materials is the accurate assignment of the ionization state at acidic and basic sites. Solution phase pK_a's are not always reliable reference points because local environments can significantly change pK_a values in solids. Herein, an approach for distinguishing R–NH₂ and R–NH₃⁺ is described based on experimental ¹⁵N chemical shift tensors principal values for a given site (i.e. <em>δ</em>₁₁, <em>δ</em>₂₂ and <em>δ</em>₃₃) from 18 model compounds. Those ¹⁵N sites that are present as R–NH₃⁺ have anisotropies between 5 and 15 ppm. In contrast, all R–NH₂ sites have anisotropies between 14 and 115 ppm. These R–NH₂ moieties can be further categorized into three subgroups. The differences observed are postulated to arise from differences in the symmetry of the intermolecular hydrogen bonding environment, or the direct attachment of the NH₂ to an aromatic ring.</div></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"138 ","pages":"Article 102018"},"PeriodicalIF":1.8,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144335597","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":"A simple formulation of dynamic magic-angle spinning NMR derived from relaxation and Floquet theories","authors":"Jérôme Hirschinger","doi":"10.1016/j.ssnmr.2025.102017","DOIUrl":"10.1016/j.ssnmr.2025.102017","url":null,"abstract":"<div><div>A simple method proposed in an insightful paper by A. J. Vega [J. Magn. Reson. 65 (1985) 252–267] is applied for calculating the effects of chemical exchange on magic-angle spinning (MAS) NMR spectra in the case of a two-site rotational jump motion. This approach which only requires two basic expressions of <span><math><mrow><msub><mi>T</mi><mn>2</mn></msub></mrow></math></span> for the limiting cases of fast and slow exchange is compared with exact numerical calculations for arbitrary rates of motion and spinning frequencies. This comparison justifies the application of relaxation theory (RT) to calculate fast-exchange lineshapes but the slow-exchange <span><math><mrow><msub><mi>T</mi><mn>2</mn></msub></mrow></math></span> time constant originally derived by A. Schmidt and S. Vega [J. Chem. Phys. 87 (1987) 6895–6907] using Floquet-perturbation theory (FPT) fails to account for the differences in the spinning sideband linewidths. In this paper, the complete FPT (cFPT) expression of the MAS spectrum is shown to account for all details of differential sideband broadening observed in the slow-exchange regime. Moreover, the RT and cFPT solutions give insight into the effects of molecular dynamics on the MAS spectra and decrease dramatically the computation time. The calculation procedure using the RT and cFPT formulas yield lineshape simulations that are in very good agreement with exact numerical results except in the intermediate-exchange regime when the sideband linewidths become comparable with or larger than the MAS rate. This is a minor drawback in practice as fast relaxation then makes quantitative measurements difficult.</div></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"138 ","pages":"Article 102017"},"PeriodicalIF":1.8,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144307767","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":"Practical aspects of Zeeman-perturbed NQR spectroscopy using an adjustable electromagnet","authors":"Alireza Nari,&nbsp;Patrick M.J. Szell,&nbsp;David L. Bryce","doi":"10.1016/j.ssnmr.2025.102014","DOIUrl":"10.1016/j.ssnmr.2025.102014","url":null,"abstract":"<div><div>Quadrupolar-perturbed solid-state NMR spectroscopy is a highly useful and well-established method for studying quadrupolar nuclei. This method relies on a high ratio of the Larmor frequency to the quadrupolar frequency and is limited, therefore, by the available magnetic field strengths suitable for NMR, which are on the order of 10¹ T. Nuclear quadrupole resonance (NQR) provides an approach to studying strongly quadrupolar isotopes, but there are technical challenges associated with measuring high-frequency transitions, and with measuring both the quadrupolar coupling constant, <em>C</em>_Q, and asymmetry parameter, <em>η</em>, with good precision. We describe here the technical and practical aspects of a modern implementation of Zeeman-perturbed NQR spectroscopy using an adjustable electromagnet, which overcomes the aforementioned challenges. This approach flips the quadrupolar-perturbed solid-state NMR method upside down, so that the quadrupolar interaction is dominant and the Zeeman interaction is the perturbation. ⁷⁹Br and ¹²⁷I Zeeman-perturbed NQR spectra are recorded for some solid bromo- and iodobenzene powders using applied magnetic fields on the order of 10⁻² T. Various experimental considerations are discussed, including the optimal magnetic field to be used, the optimization of the coil angle, frequency stepping, the simulation of spectra using an exact diagonalization of the Zeeman-quadrupolar Hamiltonian, and how to ensure high precision in the resulting quadrupolar parameters. As an example, a <em>C</em>_Q(¹²⁷) value of 2077.25 ± 1.49 MHz (with <em>η</em> = 0.114 ± 0.008) is measured for <em>sym</em>-triiodotrifluorobenzene in less than an hour at room temperature. The approach holds promise for studying strongly quadrupolar isotopes in a range of materials and obviates the need for ultrahigh magnetic fields in many situations of interest.</div></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"138 ","pages":"Article 102014"},"PeriodicalIF":1.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279234","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":"Low-power 14N decoupling at fast MAS of 70 kHz","authors":"Ekta Nehra ,&nbsp;Vipin Agarwal ,&nbsp;Yusuke Nishiyama","doi":"10.1016/j.ssnmr.2025.102006","DOIUrl":"10.1016/j.ssnmr.2025.102006","url":null,"abstract":"<div><div>Higher isotropic resolution in solids is essential for accurate assignment of the chemical shifts in multisite chemical and biological systems; consequently, the pursuit of solution-like resolution in solid samples remains an ongoing challenge. MAS provides the effective averaging of the anisotropic interactions to the first-order while the higher order interactions, such as residual dipolar splitting (RDS), and isotropic interactions like J coupling remain. With the emergence of faster MAS, RDS and J couplings become significant constraints in the resolution and sensitivity of isotropic ¹H peaks bonded to ¹⁴N. However, the dominant quadrupolar coupling hampers the decoupling of ¹H-¹⁴N, since the achievable ¹⁴N RF-field strength is much smaller than the size of the quadrupolar coupling. Therefore, ¹⁴N edited spectroscopy is typically performed in the absence of ¹⁴N decoupling, leading to broader ¹H linewidth and reduced sensitivity. In this context, we propose the continuous-wave (CW) ¹⁴N decoupling of ¹⁴N-¹H spin pair under ¹H detection at a fast MAS of 70 kHz. We experimentally show that the on-resonance low-power ¹⁴N CW irradiation at fast MAS yields the narrower linewidth. Utilizing the quadrupolar jolting frame description, a qualitative analysis of the optimum decoupling effect is provided.</div></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"137 ","pages":"Article 102006"},"PeriodicalIF":1.8,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089173","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":"Dynamic nuclear polarization of TEMPO radical cross conjugated with a thioanisole scaffold","authors":"Renny Mathew ,&nbsp;Jagriti Gupta ,&nbsp;M.D. Devadarsan ,&nbsp;Sagar Mavi ,&nbsp;Mohammed Jasil ,&nbsp;Jerry A. Fereiro ,&nbsp;Benesh Joseph ,&nbsp;Keshaba N. Parida ,&nbsp;Brijith Thomas","doi":"10.1016/j.ssnmr.2025.102005","DOIUrl":"10.1016/j.ssnmr.2025.102005","url":null,"abstract":"<div><div>Nuclear magnetic resonance (NMR) spectroscopy is an important technique for molecular structure determination but is inherently limited by its low sensitivity. Recently, the Dynamic nuclear polarization (DNP) technique has emerged as a solution to overcome the intrinsic low sensitivity of NMR spectroscopy by transferring polarization from the unpaired electron spins to nuclear spins under microwave irradiation, achieving a theoretical sensitivity enhancement of up to 658-fold for the detection of ¹H. In this study, we report the synthesis and characterization of a series of TEMPO(2,2,6,6-tetramethylpiperidine-1-oxyl)-based radicals functionalized with a thioanisole scaffold, designed to facilitate self-assembled monolayers on gold surfaces. The radicals were investigated using electron paramagnetic resonance (EPR) and DNP NMR spectroscopy. These radicals demonstrated properties consistent with the standard TEMPO while maintaining stability and functionality. At 10 mM concentration in TCE (1,1,2,2-tetrachloroethane), Radical-Imine-1 yielded a DNP enhancement factor of 3.2 for ¹H nuclei and that of standard TEMPO is around 2.8 at 14.1 T. Relaxation measurements revealed that longitudinal relaxation times (T₁) decreased with radical concentration, while transverse relaxation times (T₂) remain largely unaffected, indicating minimal perturbation from paramagnetic quenching. The structural stability and surface-binding potential of the methyl thiol group make these derivatives suitable for surface-based DNP applications.</div></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"137 ","pages":"Article 102005"},"PeriodicalIF":1.8,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143894297","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":"Extending 17O transverse relaxation measurement to satellite transitions as a direct probe of molecular dynamics in solids","authors":"Yizhe Dai ,&nbsp;Ivan Hung ,&nbsp;Zhehong Gan ,&nbsp;Gang Wu","doi":"10.1016/j.ssnmr.2025.102004","DOIUrl":"10.1016/j.ssnmr.2025.102004","url":null,"abstract":"<div><div>We report utilization of transverse relaxation rate (<em>R</em>₂) of ¹⁷O (<em>I</em> = 5/2) satellite transitions (STs) as a probe of molecular dynamics in solids. A simple theoretical model using spectral density functions is proposed to describe the general <em>R</em>₂ behaviors of half-integer quadrupolar nuclei in solids in the presence of molecular motion (or chemical exchange). Experimental ¹⁷O <em>R</em>₂ data recorded for both CT and ST from ¹⁷O-labeled NaNO₂ over a large temperature range are used to verify the theoretical predictions. Our theoretical model is shown to be fully consistent with a full quantum mechanical treatment of the chemical exchange problem involving half-integer quadrupolar nuclei in solids by numerically solving the Liouville-von Neumann equation. The new ¹⁷O ST <em>R</em>₂ method was also applied to study the carboxylate flipping motion in two [¹⁷O]carboxylic acid-pyridine adducts in the solid state. The advantages of the ST <em>R</em>₂ approach are discussed. This ST <em>R</em>₂ approach adds a new dimension to the currently available CT-based solid-state NMR techniques for probing molecular motion in solids.</div></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"137 ","pages":"Article 102004"},"PeriodicalIF":1.8,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847453","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":"Editorial: Solid-state NMR and DNP of heterogeneous biomaterials and cellular systems","authors":"Patrick C.A. van der Wel ,&nbsp;Tuo Wang","doi":"10.1016/j.ssnmr.2025.102003","DOIUrl":"10.1016/j.ssnmr.2025.102003","url":null,"abstract":"","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"137 ","pages":"Article 102003"},"PeriodicalIF":1.8,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760051","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}