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Solid State Nuclear Magnetic Resonance

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https://www.readbyqxmd.com/read/29202302/tin-chemical-shift-anisotropy-in-tin-dioxide-on-ambiguity-of-csa-asymmetry-derived-from-mas-spectra
#1
Abil E Aliev, Albert P Bartók, Jonathan R Yates
Two different axial symmetries of the 119Sn chemical shift anisotropy (CSA) in tin dioxide with the asymmetry parameter (η) of 0 and 0.27 were reported previously based on the analysis of MAS NMR spectra. By analyzing the static powder pattern, we show that the 119Sn CSA is axially symmetric. A nearly axial symmetry and the principal axis system of the 119Sn chemical shift tensor in SnO2 were deduced from periodic scalar-relativistic density functional theory (DFT) calculations of NMR parameters. The implications of fast small-angle motions on CSA parameters were also considered, which could potentially lead to a CSA symmetry in disagreement with a crystal symmetry...
November 28, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/29208317/protein-dynamics-in-the-solid-state-from-2h-nmr-lineshape-analysis-iii-momd-in-the-presence-of-magic-angle-spinning
#2
Eva Meirovitch, Zhichun Liang, Jack H Freed
We report on a new approach to the analysis of dynamic NMR lineshapes from polycrystalline (i.e., macroscopically disordered) samples in the presence of Magic Angle Spinning (MAS). This is an application of the Stochastic Liouville Equation developed by Freed and co-workers for treating restricted (i.e., microscopically ordered) motions. The 2H nucleus in an internally-mobile C-CD3 moiety serves as a prototype probe. The acronym is 2H/MOMD/MAS, where MOMD stands for "microscopic-order-macroscopic-disorder." The key elements describing internal motions - their type, the local spatial restrictions, and related features of local geometry - are treated in MOMD generally, within their rigorous three-dimensional tensorial requirements...
November 21, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/29157868/selective-observation-of-charge-storing-ions-in-supercapacitor-electrode-materials
#3
Alexander C Forse, John M Griffin, Clare P Grey
Nuclear magnetic resonance (NMR) spectroscopy has emerged as a useful technique for probing the structure and dynamics of the electrode-electrolyte interface in supercapacitors, as ions inside the pores of the carbon electrodes can be studied separately from bulk electrolyte. However, in some cases spectral resolution can limit the information that can be obtained. In this study we address this issue by showing how cross polarisation (CP) NMR experiments can be used to selectively observe the in-pore ions in supercapacitor electrode materials...
November 4, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/29145080/comparing-the-efficacy-of-solid-and-magic-echo-refocusing-sequences-applications-to-1-h-nmr-echo-spectroscopy-of-shale-rock
#4
Gregory S Boutis, Ravinath Kausik
Quantitative evaluation of the solid and viscous components of unconventional shale rock, namely kerogen and bitumen, is important for understanding reservoir quality. Short transverse coherence times, due to strong (1)H-(1)H dipolar interactions, motivates the application of solid state refocusing pulse sequences that allow for investigating components of the free-induction decay that are otherwise obscured by instrumental effects such as probe ringdown. This work reports on static, wide-line (1)H spectroscopy of shale rock and their extracted components, which include kerogen and bitumen, by the application of solid echo and magic echo pulse sequences...
November 3, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/29126075/spin-diffusion-and-1-h-spin-lattice-relaxation-in-cs2-hso4-h2po4-containing-a-small-amount-of-ammonium-ions
#5
Shigenobu Hayashi, Keiko Jimura
Inorganic solid acid salts with hydrogen bond networks frequently show very long spin-lattice relaxation times even for (1)H because the hydrogen bonds suppress motions. In the present work, the (1)H spin-lattice relaxation in Cs2(HSO4)(H2PO4) containing a small amount of ammonium ions were studied in detail by use of the effect of magic angle spinning (MAS) on the relaxation. The (1)H spin-lattice relaxation times of the acid protons decrease with increase in the content of ammonium ions. Reorientation of the NH4 group fluctuates the dipole-dipole interaction and relaxes the ammonium protons as well as the acid protons...
November 2, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/29035839/insights-into-protein-misfolding-and-aggregation-enabled-by-solid-state-nmr-spectroscopy
#6
REVIEW
Patrick C A van der Wel
The aggregation of proteins and peptides into a variety of insoluble, and often non-native, aggregated states plays a central role in many devastating diseases. Analogous processes undermine the efficacy of polypeptide-based biological pharmaceuticals, but are also being leveraged in the design of biologically inspired self-assembling materials. This Trends article surveys the essential contributions made by recent solid-state NMR (ssNMR) studies to our understanding of the structural features of polypeptide aggregates, and how such findings are informing our thinking about the molecular mechanisms of misfolding and aggregation...
October 4, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/29150197/preface-ultrafast-magic-angle-spinning-nmr
#7
EDITORIAL
Marek J Potrzebowski
No abstract text is available yet for this article.
October 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28438365/protein-conformational-dynamics-studied-by-15-n-and-1-h-r1%C3%AF-relaxation-dispersion-application-to-wild-type-and-g53a-ubiquitin-crystals
#8
Diego F Gauto, Audrey Hessel, Petra Rovó, Vilius Kurauskas, Rasmus Linser, Paul Schanda
Solid-state NMR spectroscopy can provide site-resolved information about protein dynamics over many time scales. Here we combine protein deuteration, fast magic-angle spinning (~45-60kHz) and proton detection to study dynamics of ubiquitin in microcrystals, and in particular a mutant in a region that undergoes microsecond motions in a β-turn region in the wild-type protein. We use (15)N R1ρ relaxation measurements as a function of the radio-frequency (RF) field strength, i.e. relaxation dispersion, to probe how the G53A mutation alters these dynamics...
October 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28942230/investigation-of-zeolitic-imidazolate-frameworks-using-13-c-and-15-n-solid-state-nmr-spectroscopy
#9
Scott Sneddon, Jürgen Kahr, Angelica F Orsi, David J Price, Daniel M Dawson, Paul A Wright, Sharon E Ashbrook
Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal-organic frameworks (MOFs) with extended three-dimensional networks of transition metal nodes (bridged by rigid imidazolate linkers), with potential applications in gas storage and separation, sensing and controlled delivery of drug molecules. Here, we investigate the use of (13)C and (15)N solid-state NMR spectroscopy to characterise the local structure and disorder in a variety of single- and dual-linker ZIFs. In most cases, a combination of a basic knowledge of chemical shifts typically observed in solution-state NMR spectroscopy and the use of dipolar dephasing NMR experiments to reveal information about quaternary carbon species are combined to enable spectral assignment...
September 9, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28870468/corrigendum-to-accurate-nmr-determination-of-c-h-or-n-h-distances-for-unlabeled-molecules-solid-state-nuclear-magnetic-resonance-73-2016-15-21
#10
Y Nishiyama, M Malon, M J Potrzebowski, P Paluch, J P Amoureux
No abstract text is available yet for this article.
September 1, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28501714/determination-of-polymer-crystallinity-by-the-multivariable-curve-resolution-method-in-13-c-solid-nmr-spectrum
#11
Xiaoyue Zhou, Kaipin Xu, Pei Ni, Qun Chen, Shanmin Zhang
Most of the polymers are composed of a crystal part, an amorphous part, and a transitional interfacial part. These components present disparate physical and chemical characteristics. However, it always suffers from peak overlapping in solid NMR spectrum in order to acquire polymer's crystallinity. The polyethylene oxide (PEO) sample was tested using the Torchia pulse sequence combined with the Multivariate Curve Resolution (MCR) method. A two dimensional CP/MAS spectrum containing spin-lattice relaxation time (T1) information was acquired...
September 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28472732/repetitive-experiments-of-one-or-two-pulse-sequences-in-nqr-of-spins-i-3-2-liouville-space-steady-state-ernst-angle-and-optimum-signal
#12
Christophe Odin
In NMR, the repetition of pulse sequences with a recycle time that does not allow the spin system to completely relax back to equilibrium is a well known and often used method to increase the signal to noise ratio at given total measuring time. For isolated spins I=1/2, the steady-state of a train of strictly identical pulse sequences separated by free evolution periods of same duration is described by the well known Ernst-Anderson model, and the optimum pulse angle is given by the Ernst angle. We showed recently that equivalent formula, but with super-operators in the Liouville space, can be obtained for general spins I...
September 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28433869/community-based-barriers-to-the-wider-acceptance-of-solid-state-nmr
#13
Paul Jonsen
During August 2015, the author surveyed 76 solid state NMR scientists from materials science to biology, academic to industrial, based in North America, Europe, India, China, Japan and Australia. The subject concerned barriers to the wider acceptance of solid state NMR and included the various barriers based on experimental, funding, vendor based and community aspects. This survey was confidential. However, many of the survey participants requested that at least the results of the part of the survey relevant to our community be made public...
September 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28342403/fitting-mas-nmr-spectra-in-crystals-with-local-disorder-czjzek-s-vs-maurer-s-model-for-11-b-and-71-ga-in-polycrystalline-gallium-borate
#14
K Seleznyova, N A Sergeev, M Olszewski, P Stępień, S V Yagupov, M B Strugatsky, J Kliava
A comparative analysis of the Czjzek's and Maurer's models of the joint distribution density of NMR quadrupole parameters has been carried out in view of their application to account for spectra broadening induced by local disorder in crystals. As an example of such an application, we have considered Magic Angle Spinning NMR of (11)B and (71)Ga isotopes in polycrystalline gallium borate. Computer simulations carried out using both models unambiguously show that in the case of low local disorder the Maurer's model, in contrast to the Czjzek's model, provides satisfactory fits to experimental NMR spectra...
September 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28260612/monitoring-a-simple-hydrolysis-process-in-an-organic-solid-by-observing-methyl-group-rotation
#15
Peter A Beckmann, Joseph M Bohen, Jamie Ford, William P Malachowski, Clelia W Mallory, Frank B Mallory, Andrew R McGhie, Arnold L Rheingold, Gilbert J Sloan, Steven T Szewczyk, Xianlong Wang, Kraig A Wheeler
We report a variety of experiments and calculations and their interpretations regarding methyl group (CH3) rotation in samples of pure 3-methylglutaric anhydride (1), pure 3-methylglutaric acid (2), and samples where the anhydride is slowly absorbing water from the air and converting to the acid [C6H8O3(1) + H2O → C6H10O4(2)]. The techniques are solid state (1)H nuclear magnetic resonance (NMR) spin-lattice relaxation, single-crystal X-ray diffraction, electronic structure calculations in both isolated molecules and in clusters of molecules that mimic the crystal structure, field emission scanning electron microscopy, differential scanning calorimetry, and high resolution (1)H NMR spectroscopy...
September 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28869877/solid-state-nmr-spectroscopic-trends-for-supramolecular-assemblies-and-protein-aggregates
#16
REVIEW
Rasmus Linser
Solid-state NMR is able to generate structural data on sample preparations that are explicitly non-crystalline. In particular, for amyloid fibril samples, which can comprise significant degrees of sample disorder, solid-state NMR has been used very successfully. But also solid-state NMR studies of other supramolecular assemblies that have resisted assessment by more standard methods are being performed with increasing ease and biological impact, many of which are briefly reviewed here. New technical trends with respect to structure calculation, protein dynamics and smaller sample amounts have reshaped the field of solid-state NMR recently...
August 24, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28867557/imaging-the-spatial-distribution-of-radiofrequency-field-sample-and-temperature-in-mas-nmr-rotor
#17
Hiroki Nagashima, Julien Trébosc, Olivier Lafon, Frédérique Pourpoint, Piotr Paluch, Marek J Potrzebowski, Jean-Paul Amoureux
We investigate using nutation experiments the spatial distribution of radiofrequency (rf) field, sample, temperature and cross-polarization transfer efficiency in 1.3 mm rotor. First, two-dimensional (2D) (1)H nutation experiments on silicone thin cylinders in the presence of B0 field gradient generated by shim coils are used to image the spatial distribution of rf field inside the rotor. These experiments show that the rf field is asymmetrical with respect to the center of the rotor. Moreover, they show the large inhomogeneity that still remains across the sample when using spacers, and that even in this case, the rf-field close to the drive cap is decreased to ca...
August 12, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28834782/improved-strategies-for-dnp-enhanced-2d-1-h-x-heteronuclear-correlation-spectroscopy-of-surfaces
#18
Takeshi Kobayashi, Frédéric A Perras, Umesh Chaudhary, Igor I Slowing, Wenyu Huang, Aaron D Sadow, Marek Pruski
We demonstrate that dynamic nuclear polarization (DNP)-enhanced (1)H-X heteronuclear correlation (HETCOR) measurements of hydrogen-rich surface species are better accomplished by using proton-free solvents. This approach notably prevents HETCOR spectra from being obfuscated by the solvent-derived signals otherwise present in DNP measurements. Additionally, in the hydrogen-rich materials studied here, which included functionalized mesoporous silica nanoparticles and metal organic frameworks, the use of proton-free solvents afforded higher sensitivity gains than the commonly used solvents containing protons...
August 12, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28802890/is-protein-deuteration-beneficial-for-proton-detected-solid-state-nmr-at-and-above-100%C3%A2-khz-magic-angle-spinning
#19
Diane Cala-De Paepe, Jan Stanek, Kristaps Jaudzems, Kaspars Tars, Loren B Andreas, Guido Pintacuda
(1)H-detection in solid-state NMR of proteins has been traditionally combined with deuteration for both resolution and sensitivity reasons, with the optimal level of proton dilution being dependent on MAS rate. Here we present (1)H-detected (15)N and (13)C CP-HSQC spectra on two microcrystalline samples acquired at 60 and 111 kHz MAS and at ultra-high field. We critically compare the benefits of three labeling schemes yielding different levels of proton content in terms of resolution, coherence lifetimes and feasibility of scalar-based 2D correlations under these experimental conditions...
July 25, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28759801/assignment-of-solid-state-13-c-and-1-h-nmr-spectra-of-paramagnetic-ni-ii-acetylacetonate-complexes-aided-by-first-principles-computations
#20
Syed Awais Rouf, Vibe Boel Jakobsen, Jiří Mareš, Nicholai Daugaard Jensen, Christine J McKenzie, Juha Vaara, Ulla Gro Nielsen
Recent advances in computational methodology allowed for first-principles calculations of the nuclear shielding tensor for a series of paramagnetic nickel(II) acetylacetonate complexes, [Ni(acac)2L2] with L = H2O, D2O, NH3, ND3, and PMe2Ph have provided detailed insight into the origin of the paramagnetic contributions to the total shift tensor. This was employed for the assignment of the solid-state (1,2)H and (13)C MAS NMR spectra of these compounds. The two major contributions to the isotropic shifts are by orbital (diamagnetic-like) and contact mechanism...
July 17, 2017: Solid State Nuclear Magnetic Resonance
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