Solid state nuclear magnetic resonance最新文献

{"title":"Room temperature DNP of diamond powder using frequency modulation","authors":"Daphna Shimon ,&nbsp;Kelly Cantwell ,&nbsp;Linta Joseph ,&nbsp;Chandrasekhar Ramanathan","doi":"10.1016/j.ssnmr.2022.101833","DOIUrl":"10.1016/j.ssnmr.2022.101833","url":null,"abstract":"<div><p><span><span>Dynamic nuclear polarization (DNP) is a method of enhancing </span>NMR signals<span> via the transfer of polarization from electron spins<span> to nuclear spins using microwave (MW) irradiation. In most cases, monochromatic continuous-wave (MCW) MW irradiation is used. Recently, several groups have shown that frequency modulation of the MW irradiation can result in an additional increase in DNP enhancement above that obtained with MCW. The effect of frequency modulation on the solid effect (SE) and the cross effect (CE) has previously been studied using the stable organic radical 4-hydroxy TEMPO (TEMPOL) at temperatures under 20 K. Here, in addition to the SE and CE, we discuss the effect of frequency modulation on the Overhauser effect (OE) and the truncated CE (tCE) in the room-temperature </span></span></span>¹³<span>C-DNP of diamond powders. We recently showed that diamond powders can exhibit multiple DNP mechanisms simultaneously due to the heterogeneity of P1 (substitutional nitrogen) environments within diamond crystallites. We explore how the two parameters that define the frequency modulation: (i) the Modulation frequency, f</span>_<em>m</em> (how fast the microwave frequency is varied) and (ii) the Modulation amplitude, Δω (the magnitude of the change in microwave frequency) influence the enhancement obtained via each mechanism. Frequency modulation during DNP not only allows us to improve DNP enhancement, but also gives us a way to control which DNP mechanism is most active. By choosing the appropriate modulation parameters, we can selectively enhance some mechanisms while simultaneously suppressing others.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101833"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33494485","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":"MAS-DNP enables NMR studies of insect wings","authors":"Frédéric Mentink-Vigier ,&nbsp;Samuel Eddy ,&nbsp;Terry Gullion","doi":"10.1016/j.ssnmr.2022.101838","DOIUrl":"10.1016/j.ssnmr.2022.101838","url":null,"abstract":"<div><p><span>NMR is a valuable tool for studying insects. Solid-state NMR has been used to obtain the chemical composition and gain insight into the sclerotization process of exoskeletons. There is typically little difficulty in obtaining sufficient sample quantity for exoskeletons. However, obtaining enough sample of other insect components for solid-state NMR experiments can be problematic while isotopically enriching them is near impossible. This is especially the case for insect wing membranes which is of interest to us. Issues with obtaining sufficient sample are the thickness of wing membranes is on the order of microns, each membrane region is surrounded by veins and occupies a small area, and the membranes are separated from the wing by physical dissection. Accordingly, </span>NMR signal enhancement methods are needed. MAS-DNP has a track record of providing significant signal enhancements for a wide variety of materials. Here we demonstrate that MAS-DNP is useful for providing high quality one-dimensional and two-dimensional solid-state NMR spectra on cicada wing membrane at natural isotopic abundance.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101838"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10398228","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":"New salts of teriflunomide (TFM) – Single crystal X-ray and solid state NMR investigation","authors":"Tomasz Pawlak ,&nbsp;Piotr Paluch ,&nbsp;Rafał Dolot ,&nbsp;Grzegorz Bujacz ,&nbsp;Marek J. Potrzebowski","doi":"10.1016/j.ssnmr.2022.101820","DOIUrl":"10.1016/j.ssnmr.2022.101820","url":null,"abstract":"<div><p>New salts of teriflunomide <strong>TFM</strong> (drug approved for Multiple Sclerosis treatment) with inorganic counterions: lithium (<strong>TFM_Li)</strong>, sodium (<strong>TFM_Na)</strong>, potassium (<strong>TFM_K)</strong>, rubidium (<strong>TFM_Rb)</strong>, caesium (<strong>TFM_Cs)</strong> and ammonium (<strong>TFM_NH</strong>_{<strong>4</strong>}<strong>)</strong> were prepared and investigated employing solid state NMR Spectroscopy, Powder X-ray Diffraction PXRD and Single Crystal X-ray Diffraction (SC XRD). Crystal and molecular structures of three salts: <strong>TFM_Na</strong> (CCDC: 2173257), <strong>TFM_Cs</strong> (CCDC: 2165288) and <strong>TFM_NH</strong>_{<strong>4</strong>} (CCDC: 2165281) were determined and deposited. Compared to the native <strong>TFM</strong>, for all crystalline salt structures, a conformational change of the teriflunomide molecule involving about 180-degree rotation of the end group, forming an intramolecular hydrogen bond N–H⋯O is observed. By applying a complementary multi-technique approach, employing 1D and 2D solid state MAS NMR techniques, single and powder X-ray diffraction measurements, as well as the DFT-based GIPAW calculations of NMR chemical shifts for <strong>TFM_Na</strong> and <strong>TFM_Cs</strong> allowed to propose structural features of <strong>TFM_Li</strong> for which it was not possible to obtain adequate material for single crystal X-Ray measurement.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101820"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0926204022000492/pdfft?md5=b5f36b38b63761d08c402a715bb94fef&pid=1-s2.0-S0926204022000492-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10685599","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":"Interaction frames in solid-state NMR: A case study for chemical-shift-selective irradiation schemes","authors":"Matías Chávez,&nbsp;Matthias Ernst","doi":"10.1016/j.ssnmr.2022.101834","DOIUrl":"10.1016/j.ssnmr.2022.101834","url":null,"abstract":"<div><p>Interaction frames play an important role in describing and understanding experimental schemes in magnetic resonance. They are often used to eliminate dominating parts of the spin Hamiltonian, e.g., the Zeeman Hamiltonian in the usual (Zeeman) rotating frame, or the radio-frequency-field (rf) Hamiltonian to describe the efficiency of decoupling or recoupling sequences. Going into an interaction frame can also make parts of a time-dependent Hamiltonian time independent like the rf-field Hamiltonian in the usual (Zeeman) rotating frame. Eliminating the dominant term often allows a better understanding of the details of the spin dynamics. Going into an interaction frame can also reduces the energy-level splitting in the Hamiltonian leading to a faster convergence of perturbation expansions, average Hamiltonian, or Floquet theory. Often, there is no obvious choice of the interaction frame to use but some can be more convenient than others. Using the example of frequency-selective dipolar recoupling, we discuss the differences, advantages, and disadvantages of different choices of interaction frames. They always include the complete radio-frequency Hamiltonian but can also contain the chemical shifts of the spins and may or may not contain the effective fields over one cycle of the pulse sequence.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101834"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0926204022000637/pdfft?md5=34c8cd6a39dc8784f9deca371b37fc6d&pid=1-s2.0-S0926204022000637-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10341544","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":"Monitoring the influence of additives on the crystallization processes of glycine with dynamic nuclear polarization solid-state NMR","authors":"Marie Juramy ,&nbsp;Paolo Cerreia Vioglio ,&nbsp;Fabio Ziarelli ,&nbsp;Stéphane Viel ,&nbsp;Pierre Thureau ,&nbsp;Giulia Mollica","doi":"10.1016/j.ssnmr.2022.101836","DOIUrl":"10.1016/j.ssnmr.2022.101836","url":null,"abstract":"<div><p>Crystallization is fundamental in many domains, and the investigation of the sequence of solid phases produced as a function of crystallization time is thus key to understand and control crystallization processes. Here, we used a solid-state nuclear magnetic resonance strategy to monitor the crystallization process of glycine, which is a model compound in polymorphism, under the influence of crystallizing additives, such as methanol or sodium chloride. More specifically, our strategy is based on a combination of low-temperatures and dynamic nuclear polarization (DNP) to trap and detect transient crystallizing forms, which may be present only in low quantities. Interestingly, our results show that these additives yield valuable DNP signal enhancements even in the absence of glycerol within the crystallizing solution.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101836"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0926204022000650/pdfft?md5=43ea233eefc61f244122c5bcc4bf4599&pid=1-s2.0-S0926204022000650-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10335669","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":"Teaching product operators using the Vega diagram","authors":"Jörg Matysik ,&nbsp;Chen Song ,&nbsp;Pavlo Bielytskyi ,&nbsp;A. Alia","doi":"10.1016/j.ssnmr.2022.101830","DOIUrl":"10.1016/j.ssnmr.2022.101830","url":null,"abstract":"<div><p>We all will remember Shimon Vega (1942–2021) as wonderful human and scientist. Paramount examples of his scientific work are quoted in this special issue dedicated to his memory. This article is dedicated to remember Shimon Vega as a fantastic teacher. To introduce to the world of <em>product operators</em>, Shimon created a simple scheme that we now call the <em>Vega diagram</em>. It allows for fast analysis of pulse sequences for AX spin systems. Here, we want to document this scheme for future generations.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101830"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33501305","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":"Improving the accuracy of GIPAW chemical shielding calculations with cluster and fragment corrections","authors":"Joshua D. Hartman ,&nbsp;James K. Harper","doi":"10.1016/j.ssnmr.2022.101832","DOIUrl":"10.1016/j.ssnmr.2022.101832","url":null,"abstract":"&lt;div&gt;&lt;p&gt;&lt;span&gt;Ab initio methods&lt;span&gt; for predicting NMR parameters in the solid state are an essential tool for assigning experimental spectra and play an increasingly important role in structural characterizations. Recently, a molecular correction (MC) technique has been developed which combines the strengths&lt;span&gt; of plane-wave methods (GIPAW) with single molecule calculations employing Gaussian basis sets. The GIPAW + MC method relies on a periodic calculation performed at a lower level of theory to model the crystalline environment. The GIPAW result is then corrected using a single molecule calculation performed at a higher level of theory. The success of the GIPAW + MC method in predicting a range of NMR parameters is a result of the highly local character of the tensors underlying the NMR observable. However, in applications involving strong intermolecular interactions we find that expanding the region treated at the higher level of theory more accurately captures local many-body contributions to the &lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;math&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;none&gt;&lt;/none&gt;&lt;none&gt;&lt;/none&gt;&lt;mprescripts&gt;&lt;/mprescripts&gt;&lt;none&gt;&lt;/none&gt;&lt;mrow&gt;&lt;mn&gt;15&lt;/mn&gt;&lt;/mrow&gt;&lt;/mmultiscripts&gt;&lt;/math&gt;&lt;/span&gt; NMR chemical shielding (CS) tensor. We propose alternative corrections to GIPAW which capture interactions between adjacent molecules at a higher level of theory using either fragment or cluster-based calculations. Benchmark calculations performed on &lt;span&gt;&lt;math&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;none&gt;&lt;/none&gt;&lt;none&gt;&lt;/none&gt;&lt;mprescripts&gt;&lt;/mprescripts&gt;&lt;none&gt;&lt;/none&gt;&lt;mrow&gt;&lt;mn&gt;15&lt;/mn&gt;&lt;/mrow&gt;&lt;/mmultiscripts&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;none&gt;&lt;/none&gt;&lt;none&gt;&lt;/none&gt;&lt;mprescripts&gt;&lt;/mprescripts&gt;&lt;none&gt;&lt;/none&gt;&lt;mrow&gt;&lt;mn&gt;13&lt;/mn&gt;&lt;/mrow&gt;&lt;/mmultiscripts&gt;&lt;/math&gt;&lt;/span&gt; data sets show that these advanced GIPAW-corrected calculations improve the accuracy of chemical shielding tensor predictions relative to existing methods. Specifically, cluster-based &lt;span&gt;&lt;math&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;none&gt;&lt;/none&gt;&lt;none&gt;&lt;/none&gt;&lt;mprescripts&gt;&lt;/mprescripts&gt;&lt;none&gt;&lt;/none&gt;&lt;mrow&gt;&lt;mn&gt;15&lt;/mn&gt;&lt;/mrow&gt;&lt;/mmultiscripts&gt;&lt;/math&gt;&lt;/span&gt; corrections show a 24% and 17% reduction in RMS error relative to GIPAW and GIPAW + MC calculations, respectively. Comparing the benchmark data sets using multiple computational models demonstrates that &lt;span&gt;&lt;math&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;none&gt;&lt;/none&gt;&lt;none&gt;&lt;/none&gt;&lt;mprescripts&gt;&lt;/mprescripts&gt;&lt;none&gt;&lt;/none&gt;&lt;mrow&gt;&lt;mn&gt;15&lt;/mn&gt;&lt;/mrow&gt;&lt;/mmultiscripts&gt;&lt;/math&gt;&lt;/span&gt; CS tensor calculations are significantly more sensitive to intermolecular interactions relative to &lt;span&gt;&lt;math&gt;&lt;mmultiscripts&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;none&gt;&lt;/none&gt;&lt;none&gt;&lt;/none&gt;&lt;mprescripts&gt;&lt;/mprescripts&gt;&lt;none&gt;&lt;/none&gt;&lt;mrow&gt;&lt;mn&gt;13&lt;/mn&gt;&lt;/mrow&gt;&lt;/mmultiscripts&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;. However, fragment and cluster-based corrections that include direct hydrogen bond&lt;span&gt; partners are sufficient for optimizing the accuracy of GIPAW-corrected methods. Finally, GIPAW","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101832"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10335631","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":"19F fast MAS (60–111 kHz) dipolar and scalar based correlation spectroscopy of organic molecules and pharmaceutical formulations","authors":"Gal Porat-Dahlerbruch ,&nbsp;Jochem Struppe ,&nbsp;Caitlin M. Quinn ,&nbsp;Angela M. Gronenborn ,&nbsp;Tatyana Polenova","doi":"10.1016/j.ssnmr.2022.101831","DOIUrl":"https://doi.org/10.1016/j.ssnmr.2022.101831","url":null,"abstract":"<div><p>¹⁹<span>F magic angle spinning (MAS) NMR spectroscopy is a powerful tool for characterization of fluorinated solids. The recent development of </span>¹⁹<span>F MAS NMR probes, operating at spinning frequencies of 60–111 kHz, enabled analysis of systems spanning from organic molecules to pharmaceutical formulations to biological assemblies, with unprecedented resolution. Herein, we systematically evaluate the benefits of high MAS frequencies (60–111 kHz) for 1D and 2D </span>¹⁹<span>F-detected experiments in two pharmaceuticals, the antimalarial drug<span> mefloquine<span> and a formulation of the cholesterol-lowering drug atorvastatin calcium. We demonstrate that </span></span></span>¹<span><span>H decoupling is essential and that scalar-based, heteronuclear single quantum coherence (HSQC) and </span>heteronuclear multiple quantum coherence (HMQC) correlation experiments become feasible and efficient at the MAS frequency of 100 kHz. This study opens doors for the applications of high frequency </span>¹⁹<span>F MAS NMR to a wide range of problems in chemistry and biology.</span></p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101831"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91684900","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":"Improved resolution for spin-3/2 isotopes in solids via the indirect NMR detection of triple-quantum coherences using the T-HMQC sequence","authors":"Racha Bayzou ,&nbsp;Julien Trébosc ,&nbsp;Ivan Hung ,&nbsp;Zhehong Gan ,&nbsp;Andrew Rankin ,&nbsp;Olivier Lafon ,&nbsp;Jean-Paul Amoureux","doi":"10.1016/j.ssnmr.2022.101835","DOIUrl":"10.1016/j.ssnmr.2022.101835","url":null,"abstract":"<div><p><span>The indirect NMR detection of quadrupolar nuclei<span> in solids under magic-angle spinning (MAS) is possible with the through-space HMQC (heteronuclear multiple-quantum coherence) scheme incorporating the TRAPDOR (transfer of population in double-resonance) dipolar recoupling. This sequence, called T-HMQC, exhibits limited </span></span><em>t</em>₁-noise. In this contribution, with the help of numerical simulations of spin dynamics, we show that most of the time, the fastest coherence transfer in the T-HMQC scheme is achieved when TRAPDOR recoupling employs the highest radiofrequency (rf) field compatible with the probe specifications. We also demonstrate how the indirect detection of the triple-quantum (3Q) coherences of spin-3/2 quadrupolar nuclei in solids improves the spectral resolution for these isotopes. The sequence is then called T-HMQC₃. We demonstrate the gain in resolution provided by this sequence for the indirect proton detection of ³⁵Cl nuclei in <span>l</span>-histidine∙HCl and <span>l</span>-cysteine∙HCl, as well as that of ²³Na isotope in NaH₂PO₄. These experiments indicate that the gain in resolution depends on the relative values of the chemical and quadrupolar-induced shifts (QIS) for the different spin-3/2 species. In the case of NaH₂PO₄, we show that the transfer efficiency of the T-HMQC₃ sequence employing an rf-field of 80 kHz with a MAS frequency of 62.5 kHz reaches 75% of that of the <em>t</em>₁-noise eliminated (TONE) dipolar-mediated HMQC (<em>D</em>-HMQC) scheme.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101835"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10337117","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 case study on the influence of hydrophilicity on the signal enhancement by dynamic nuclear polarization","authors":"Sonja C. Döller ,&nbsp;Torsten Gutmann ,&nbsp;Markus Hoffmann ,&nbsp;Gerd Buntkowsky","doi":"10.1016/j.ssnmr.2022.101829","DOIUrl":"10.1016/j.ssnmr.2022.101829","url":null,"abstract":"<div><p><span>In this work, the behavior of four different commercially available polarizing agents is investigated employing the non-ionic model surfactant<span> 1-octanol as analyte. A relative method for the comparison of the proportion of the direct and indirect polarization transfer<span> pathways is established, allowing a direct comparison of the polarization efficacy for different radicals and different parts of the 1-octanol molecule despite differences in radical concentration or sample amount. With this approach, it could be demonstrated that the hydrophilicity is a key factor in the way polarization is transferred from the polarizing agent to the analyte. These findings are confirmed by the determination of buildup times T</span></span></span>_b<span>, illustrating that the choice of polarizing agent plays an essential role in ensuring an optimal polarization transfer and therefore the maximum amount of enhancement possible for DNP enhanced NMR measurements.</span></p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"122 ","pages":"Article 101829"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10397171","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}