Solid state nuclear magnetic resonance最新文献

{"title":"To what extent do bond length and angle govern the 13C and 1H NMR response to weak CH⋯O hydrogen bonds? A case study of caffeine and theophylline cocrystals","authors":"Scott A. Southern ,&nbsp;David L. Bryce","doi":"10.1016/j.ssnmr.2022.101795","DOIUrl":"10.1016/j.ssnmr.2022.101795","url":null,"abstract":"<div><p><span><span>Weak hydrogen bonds<span> are important structure-directing elements in supramolecular chemistry and biochemistry. We consider here weak CH⋯O hydrogen bonds in a series of cocrystals of </span></span>theophylline and caffeine and assess to what extent the CH⋯O distance and angle govern the observed </span>¹³C and ¹H isotropic chemical shifts. Gauge-including projector-augmented wave density functional theory (GIPAW DFT) calculations consistently predict a decrease in the ¹³C and ¹<span>H magnetic shielding constants upon hydrogen bond formation on the order of 2–5 ppm (</span>¹³C) and 1–2 ppm (¹H). These trends are reproduced using the machine-learning approach implemented in ShiftML. Experimental ¹³C and ¹<span><span>H chemical shifts obtained for powdered samples using one-dimensional NMR spectroscopy as well as </span>heteronuclear correlation (HETCOR) spectroscopy correlate well with the GIPAW DFT results. However, the experimental </span>¹³C NMR response only correlates moderately well with the hydrogen bond length and angle, while the experimental ¹H chemical shifts only show very weak correlations to these local structural elements. DFT computations on isolated imidazole-formaldehyde models show that the ¹³C and ¹H chemical shifts generally decrease with the C⋯O distance but show no clear dependence on the CH⋯O angle. These results demonstrate that the ¹³C and ¹H response to weak CH⋯O hydrogen bonding is influenced significantly by additional weak contacts within cocrystal heterodimeric units.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"119 ","pages":"Article 101795"},"PeriodicalIF":3.2,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48434460","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":"Butane isomers mobility and framework dynamics in UiO-66 (Zr) MOF: Impact of the hydroxyl groups in zirconia cluster","authors":"Alexander E. Khudozhitkov ,&nbsp;Sergei S. Arzumanov ,&nbsp;Daniil I. Kolokolov ,&nbsp;Alexander G. Stepanov","doi":"10.1016/j.ssnmr.2022.101784","DOIUrl":"10.1016/j.ssnmr.2022.101784","url":null,"abstract":"<div><p><span>UiO-66 (Zr) is a metal-organic framework (MOF) known for its thermal and chemical stability and wide range of adsorption-based applications. This MOF exhibits high separation selectivity for butane isomers. It has been earlier inferred that the separation performance of the material depends on the hydroxylation state of the zirconia cluster. In this contribution, we apply </span>²H solid-state NMR to characterize the dynamics of both the MOF organic framework itself and butane isomers in hydroxylated and dehydroxylated forms of UiO-66. It is established that the rate of π-flipping and the amplitude of the phenylene ring plane librations in the framework are higher for the dehydroxylated form. Self-diffusion coefficients of butane isomers have been estimated for both forms of UiO-66. The diffusivity is higher for <em>n</em><span>-butane in the dehydroxylated form, whereas the diffusion of isobutane is not affected by the presence of OH groups in the zirconia cluster of the MOF. Higher diffusivity of </span><em>n</em>-butane in dehydroxylated form is accounted for by the larger effective diameter of the window between the adjacent cages in this form, which arises from faster rotation and larger amplitude of framework linker libration. This rationalizes the higher efficiency of the dehydroxylated form of UiO-66(Zr) material for butane isomers separation.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"118 ","pages":"Article 101784"},"PeriodicalIF":3.2,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45870397","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":"Characterization of crystalline and amorphous forms of irbesartan by multi-nuclear solid-state NMR","authors":"Marcin Skotnicki ,&nbsp;Paul Hodgkinson","doi":"10.1016/j.ssnmr.2022.101783","DOIUrl":"10.1016/j.ssnmr.2022.101783","url":null,"abstract":"<div><p><span>Irbesartan (IRB) is an antihypertensive drug which exhibits the rare phenomenon of desmotropy; its 1</span><em>H</em>- and 2<em>H</em><span><span>- tetrazole </span>tautomers<span> can be isolated as distinct crystalline forms. The crystalline forms of IRB are poorly soluble, hence the amorphous<span> form is potentially of interest for its faster dissolution rate. The tautomeric form and the nature of hydrogen bonding in amorphous IRB are unknown. In this study, crystalline form A and amorphous form of irbesartan were studied using </span></span></span>¹³C, ¹⁵N and ¹H solid-state NMR. Variable-temperature ¹³C SSMNR studies showed alkyl chain disorder in the crystalline form of IRB, which may explain the conflicting literature crystal structures of form A (the marketed form). ¹⁵N NMR indicates that the amorphous material contains an approximately 2:1 ratio of 1<em>H</em>- and 2<em>H</em>-tetrazole tautomers. Static ¹<span>H SSNMR and relaxation time measurements confirmed different molecular mobilities of the samples and provided molecular-level insight into the nature of the glass transition. SSNMR is shown to be a powerful technique to investigate the solid state of disordered active pharmaceutical ingredients.</span></p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"118 ","pages":"Article 101783"},"PeriodicalIF":3.2,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49176733","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":"Separating an overlapped 1H peak and identifying its 1H-1H correlations with the use of single-channel 1H solid-state NMR at fast MAS","authors":"Nghia Tuan Duong ,&nbsp;Vipin Agarwal ,&nbsp;Yusuke Nishiyama","doi":"10.1016/j.ssnmr.2022.101774","DOIUrl":"10.1016/j.ssnmr.2022.101774","url":null,"abstract":"<div><p>Fast magic-angle spinning (≥60 ​kHz) technique has enabled the acquisition of high-resolution ¹H NMR spectra of solid materials. However, the spectral interpretation is still difficult because the ¹<span>H peaks are overlapped due to the narrow chemical shift range and broad linewidths. An additional </span>¹³C or ¹⁴N or ¹H dimension possibly addresses the issues of overlapped proton resonances, but it leads to the elongated experimental time. Herein, we introduce a single-channel ¹H experiment to separate the overlapped ¹H peak and identify its spatially proximal ¹H–¹<span>H correlations. This sequence combines selective excitation, selective </span>¹H–¹<span>H polarization transfer by selective recoupling of protons (SERP), and broadband </span>¹H recoupling by back-to-back (BABA) recoupling sequences. The concept for ¹H separation is based on (i) the selective excitation of a well-resolved ¹H peak and (ii) the selective dipolar polarization transfer from this isolated ¹H peak to one of the ¹H peaks in the overlapped/poor resolution region by SERP and (iii) the detection of ¹H–¹H correlations from these two ¹H peaks to other neighboring ¹Hs by BABA. We demonstrated the applicability of this approach to identify overlapped peaks on two molecules, β-L-aspartyl-<span>l</span><span>-alanine and Pioglitazone.HCl. The sequence allows the clear observation of </span>¹H–¹H correlations from an overlapped ¹H peak without an additional heteronuclear dimension and ensures efficient polarization transfers that leads to twelve fold reduction in experimental time compared to ¹⁴N edited experiments. The limitation and the conditions of applicability for this approach are discussed in detail.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"117 ","pages":"Article 101774"},"PeriodicalIF":3.2,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39837922","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":"Structural characterization of interfaces in silica core-alumina shell microspheres by solid-state NMR spectroscopy","authors":"Andrea Simion ,&nbsp;Mihai Vasilescu ,&nbsp;Claudiu Filip ,&nbsp;Milica Todea ,&nbsp;Marieta Mureșan-Pop ,&nbsp;Simion Simon","doi":"10.1016/j.ssnmr.2022.101773","DOIUrl":"10.1016/j.ssnmr.2022.101773","url":null,"abstract":"<div><p><span><span>Atomic-scale description of surfaces and interfaces in core-shell aluminosilicate materials is not fully elucidated, partially due to their </span>amorphous character and complex mechanisms that govern their properties. In this paper, new insights into nanostructured core-shell aluminosilicates have been demonstrated, by using different solid-state NMR methods, i.e </span>²⁹Si, ²⁹Si cross-polarization (CP), ²⁷Al, ²⁷Al triple-quantum (3Q), and ¹H–²⁷<span><span><span>Al heteronuclear correlation (HETCOR) </span>MAS<span> NMR. For this purpose, nanostructured silica<span><span> core-alumina shell microspheres, undoped and doped with </span>gadolinium<span> ions respectively, obtained by a chemical synthesis based on the Stöber method for the silica core and electrostatic attraction for developing the alumina shell were studied. As a result, a new alumino-silicate layer formation was proved at the interface between silica core, where </span></span></span></span>aluminum<span> diffuses, on small scale, in the silica network, and alumina shell, where silicon ions migrate, on a larger scale, in the alumina network, leading to a stable core-shell structure. Moreover, this process is accompanied by significant local structural changes in the transition zone, particularly at the aluminum neighborhood, which is quite well understood now, with the power of solid-state NMR spectroscopy.</span></span></p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"117 ","pages":"Article 101773"},"PeriodicalIF":3.2,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39927776","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 in battery materials","authors":"Shira Haber,&nbsp;Michal Leskes","doi":"10.1016/j.ssnmr.2021.101763","DOIUrl":"10.1016/j.ssnmr.2021.101763","url":null,"abstract":"<div><p><span>The increasing need for portable and large-scale energy storage systems requires development of new, long lasting and highly efficient battery systems. </span>Solid state NMR<span><span> spectroscopy has emerged as an excellent method for characterizing battery materials. Yet, it is limited when it comes to probing thin interfacial layers which play a central role in the performance and lifetime of battery cells. Here we review how Dynamic Nuclear Polarization<span> (DNP) can lift the sensitivity limitation and enable detection of the electrode-electrolyte interface, as well as the bulk of some electrode and electrolyte systems. We describe the current challenges from the point of view of materials development; considering how the unique electronic, magnetic and chemical properties differentiate battery materials from other applications of DNP in materials science. We review the current applications of exogenous and endogenous DNP from radicals, conduction electrons and paramagnetic </span></span>metal ions. Finally, we provide our perspective on the opportunities and directions where battery materials can benefit from current DNP methodologies as well as project on future developments that will enable NMR investigation of battery materials with sensitivity and selectivity under ambient conditions.</span></p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"117 ","pages":"Article 101763"},"PeriodicalIF":3.2,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39712628","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":"Effect of cross polarization radiofrequency phases on signal phase","authors":"S. Chandra Shekar ,&nbsp;Wancheng Zhao ,&nbsp;Thomas K. Weldeghiorghis,&nbsp;Tuo Wang","doi":"10.1016/j.ssnmr.2021.101771","DOIUrl":"10.1016/j.ssnmr.2021.101771","url":null,"abstract":"<div><p><span>Utilizing phases of radio frequency (RF) pulses to manipulate spin dynamics is routine in NMR and MRI, leading to spectacular techniques like phase cycling. In a very different area, cross polarization (CP) also has a long history as part of a vast number of solid-state NMR pulse sequences. However, a detailed study devoted to the effect of CP RF phases on </span>NMR signal<span>, seems not to be readily available. From first principles, we arrive at a simple dependence of NMR signal on arbitrary CP RF phases, for static and MAS conditions, accompanied by experimental verification. In the process, the CP propagator emerges as a product of RF “pulses” and a period of “free precession”, conforming to coherence transfer pathway theory. The theoretical expressions may lend confidence for dealing with CP blocks with tunable phases in pulse sequences.</span></p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"117 ","pages":"Article 101771"},"PeriodicalIF":3.2,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39776728","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":"Application of solid-state NMR techniques for structural characterization of metal-organic frameworks","authors":"Caiyan He ,&nbsp;Shenhui Li ,&nbsp;Yuqing Xiao ,&nbsp;Jun Xu ,&nbsp;Feng Deng","doi":"10.1016/j.ssnmr.2022.101772","DOIUrl":"10.1016/j.ssnmr.2022.101772","url":null,"abstract":"<div><p><span>Solid-state NMR can afford the structural information about the chemical composition, local environment, and spatial coordination at the atomic level, which has been extensively applied to characterize the detailed structure and host-guest interactions in metal-organic frameworks (MOFs). In this review, recent advances for the structural characterizations of MOFs using versatile solid-state NMR techniques were briefly introduced. High-field sensitivity-enhanced solid-state NMR method enabled the direct observation of metal centers in MOFs containing low-γ nuclei. Two-dimensional (2D) homo- and hetero-nuclear correlation </span>MAS NMR experiments provided the spatial proximity among linkers, metal clusters and the introduced guest molecules. Moreover, quantitative measurement of inter-nuclear distances using solid-state NMR provided valuable structural information about the connectivity geometry as well as the host-guest interactions within MOFs. Furthermore, solid-state NMR has exhibited great potential for unraveling the structure property of MOFs containing paramagnetic metal centers.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"117 ","pages":"Article 101772"},"PeriodicalIF":3.2,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39812758","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":"Quantifying the quadrupolar interaction by 45Sc-NMR spectroscopy of single crystals","authors":"Otto E.O. Zeman,&nbsp;Thomas Bräuniger","doi":"10.1016/j.ssnmr.2022.101775","DOIUrl":"10.1016/j.ssnmr.2022.101775","url":null,"abstract":"<div><p><span>Single crystals of the compound [</span><span><math><msub><mrow><mrow><mo>{</mo><mrow><mi>S</mi><mi>c</mi><msub><mrow><mrow><mo>(</mo><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi></mrow><mo>)</mo></mrow></mrow><mrow><mn>5</mn></mrow></msub><mrow><mo>(</mo><mrow><mi>μ</mi><mo>-</mo><mi>O</mi><mi>H</mi></mrow><mo>)</mo></mrow></mrow><mo>}</mo></mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>]Cl₄ ⋅ 2H₂O were studied by ⁴⁵<span>Sc-NMR, with the effect of the quadrupolar coupling interaction on the spectra of the spin-7/2 nucleus analysed in the hierarchical framework of perturbation theory. Orientation-dependent spectra acquired at </span><em>B</em>₀ = 17.6 T showed strong second-order effects due to the comparatively large coupling constant of <em>χ</em> = |14.613 ± 0.006| MHz, with an associated asymmetry parameter of <em>η</em>_<em>Q</em> = 0.540 9 ± 0.000 4. By analysing the splittings of the ±3/2 satellites, which in good approximation are subjected to first-order effects only, the full quadrupolar coupling tensor could be determined. The second-order effects caused by this tensor were calculated according to theoretical predictions for all orientations, and subtracted from both the centres of gravity of the satellites, and the central transitions. This allowed extraction of the full chemical shift tensor, with the eigenvalues being <em>δ</em>₁₁ = (5.6 ± 0.9) ppm, <em>δ</em>₂₂ = (12.4 ± 0.9) ppm, and <em>δ</em>₃₃ = (38.5 ± 0.9) ppm. In spectra acquired at a lower magnetic field of <em>B</em>₀ = 9.4 T, third-order effects could be detected, and similarly quantified using analytical expressions.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"117 ","pages":"Article 101775"},"PeriodicalIF":3.2,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39855637","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":"Protonation tuned dipolar order mediated 1H→13C cross-polarization for dissolution-dynamic nuclear polarization experiments","authors":"Stuart J. Elliott ,&nbsp;Quentin Stern,&nbsp;Olivier Cala,&nbsp;Sami Jannin","doi":"10.1016/j.ssnmr.2021.101762","DOIUrl":"https://doi.org/10.1016/j.ssnmr.2021.101762","url":null,"abstract":"<div><p><span>A strategy of dipolar order mediated nuclear spin polarization transfer has recently been combined with dissolution-dynamic nuclear polarization (</span><em>d</em><span>DNP) and improved by employing optimized shaped radiofrequency pulses and suitable molecular modifications. In the context of </span><em>d</em>DNP experiments, this offers a promising means of transferring polarization from high-gamma ¹H spins to insensitive ¹³C spins with lower peak power and lower energy compared with state-of-the-art cross-polarization schemes. The role of local molecular groups and the glassing matrix protonation level are both postulated to play a key role in the polarization transfer pathway via an intermediary reservoir of dipolar spin order. To gain appreciation of the mechanisms involved in the dipolar order mediated polarization transfer under <em>d</em>DNP conditions, we investigate herein the influence of the pivotal characteristics of the sample makeup: (<em>i</em>) revising the protonation level for the constituents of the DNP glass; and (<em>ii</em>) utilizing deuterated molecular derivatives. Experimental demonstrations are presented for the case of [1–¹³<span>C]sodium acetate. We find that the proton sample molarity has a large impact on both the optimal parameters and the performance of the dipolar order mediated cross-polarization sequence, with the </span>¹³C signal build-up time drastically shortened in the case of high solvent protonation levels. In the case of a deuterated molecular derivative, we observe that the nearby ²<span>H substituted methyl group is deleterious to the </span>¹H→¹³C transfer phenomenon (particularly at low levels of sample protonation). Overall, increased solvent protonation makes the dipolar order governed polarization transfer significantly faster and more efficient. This study sheds light on the influential sample formulation traits which govern the dipolar order-controlled transfer of polarization and indicates that the polarization transfer efficiencies of deuterated molecules can be boosted and reach high performances simply by adequate solvent protonation.</p></div>","PeriodicalId":21937,"journal":{"name":"Solid state nuclear magnetic resonance","volume":"116 ","pages":"Article 101762"},"PeriodicalIF":3.2,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91640813","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}