Investigation of Lead Borosilicate Glass Structure With 207Pb and 11B Solid-State NMR

2000 ◽  
Vol 658 ◽  
Author(s):  
James M. Gibson ◽  
Frederick G. Vogt ◽  
Amy S. Barnes ◽  
Karl T. Mueller
Keyword(s):  
Solid State ◽  
Structural Information ◽  
Structural Parameters ◽  
Glass Structure ◽  
Active Role ◽  
Magic Angle Spinning ◽  
Lead Content ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Borosilicate Glasses

ABSTRACTA series of three lead borosilicate glasses were synthesized and analyzed for structural information with both 11B and 207Pb solid-state nuclear magnetic resonance (NMR) spectroscopic methods. Results showed that increasing lead content caused lead to take a more active role in the network as a former and that the populations in these sites can be approximately quantified. 207Pb phase-adjusted-spinning sidebands (PASS), 11B magic-angle spinning (MAS), and 11B multiple-quantum MAS (MQMAS) experiments were used to determine structural parameters for the two nuclei. The 207Pb PASS experiment showed that at higher lead content, more covalent bonding was present. This principle was demonstrated in both an overall shift of the spectral resonances and a quantitative change in site ratios. The 11B MAS experiment showed that the ratio of BO3 to BO4 units was dependent on the amount of lead and boron, consistent with previous studies. Preliminary 11B MQMAS experiments failed to detect any BO3– units, previously hypothesized to exist in this system.

23Na magic-angle spinning and double-rotation NMR study of solid forms of sodium valproate

2014 ◽  
Vol 92 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Nuiok M. Dicaire ◽  
Frédéric A. Perras ◽  
David L. Bryce
Keyword(s):  
Solid State ◽  
Sodium Valproate ◽  
Nmr Spectra ◽  
Structural Information ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Asymmetric Unit ◽  
Nmr Study ◽  
Angle Spinning

Sodium valproate is a pharmaceutical with applications in the treatment of epilepsy, bipolar disorder, and other ailments. Sodium valproate can exist in many hydrated and acid-stabilized forms in the solid state, and it can be difficult to obtain precise structural information about many of these. Here, we present a 13C and 23Na solid-state NMR study of several forms of sodium valproate, only one of which has been previously structurally characterized by single-crystal X-ray diffraction. 23Na magic-angle spinning (MAS), double-rotation (DOR), and multiple-quantum magic-angle spinning (MQMAS) NMR spectra are shown to provide useful information on the number of molecules in the asymmetric unit, the local coordination geometry of the sodium cations, and the presence of amorphous phases. Two previously identified forms are shown to be highly similar, or identical, according to the 23Na NMR data. The utility of carrying out both DOR and MQMAS NMR experiments to identify all crystallographically unique sites is demonstrated. 13C cross-polarization MAS NMR spectra also provide complementary information on the number of molecules in the asymmetric unit and the crystallinity of the sample.

scholarly journals Solid State NMR: A Powerful Tool for the Characterization of Borophosphate Glasses

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 428 ◽  
Author(s):  
Grégory Tricot ◽  
Lazzat Alpysbay ◽  
Bertrand Doumert
Keyword(s):  
Solid State ◽  
Quantum Coherence ◽  
Glass Structure ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Local Order ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Borophosphate Glasses ◽  
Heteronuclear Multiple Quantum Coherence

This review will show how solid state nuclear magnetic resonance (NMR) has contributed to a better understanding of the borophosphate glass structure. Over the last fifteen years, 1D and 2D magic angle spinning (MAS)-NMR has been used to produce key information about both local and medium range organization in this type of glass. After a brief presentation on borophosphate glasses, the paper will focus on the description of the local order of phosphate and borate species obtained by 1D 31P-and 11B-MAS-NMR experiments, with a special emphasis on the improvements obtained at high magnetic fields on the borate speciation description. The last part of this review will show how correlation NMR provided new insights into the intermediate length scale order. Special attention will be paid to the quantitative data retrieved from 11B/31P REDOR-based NMR sequences and to the qualitative connectivity schemes observed on the 2D 11B/31P maps edited with the heteronuclear multiple quantum coherence (HMQC) NMR techniques.

scholarly journals Combination of solid state NMR and DFT calculation to elucidate the state of sodium in hard carbon electrodes

2016 ◽  
Vol 4 (34) ◽  
pp. 13183-13193 ◽  
Author(s):  
Ryohei Morita ◽  
Kazuma Gotoh ◽  
Mika Fukunishi ◽  
Kei Kubota ◽  
Shinichi Komaba ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Dft Calculation ◽  
Magic Angle Spinning ◽  
The State ◽  
Mas Nmr ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Hard Carbon ◽  
Angle Spinning

We examined the state of sodium electrochemically inserted in HC prepared at 700–2000 °C using solid state Na magic angle spinning (MAS) NMR and multiple quantum (MQ) MAS NMR.

Solid-state 17O NMR Study of Small Biological Compounds

2007 ◽  
Vol 62 (11) ◽  
pp. 1422-1432 ◽  
Author(s):  
Kazuhiko Yamada ◽  
Tadashi Shimizu ◽  
Yoshida Mitsuru ◽  
Miwako Asanuma ◽  
Masataka Tansho ◽  
...  
Keyword(s):  
Solid State ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Peptide Analysis ◽  
17O Nmr ◽  
Nmr Study ◽  
Biological Compounds ◽  
Nmr Tensors ◽  
Angle Spinning

We present a systematic experimental and theoretical investigation of the oxygen chemical shielding and electric-field-gradient tensors in polycrystalline amino acids and a peptide. Analysis of the 17O magic-angle-spinning (MAS), multiple-quantum MAS, and stationary nuclear magnetic resonance (NMR) spectra yield the magnitudes and the relative orientations between the two NMR tensors. The obtained 17O NMR parameters are sensitive to the hydrogen bond environments. We also demonstrate that solid-state 17O NMR is potentially useful for studying the secondary structures of peptides and proteins.

scholarly journals Dihedral Angle Measurements for Structure Determination by Biomolecular Solid-State NMR Spectroscopy

2021 ◽  
Vol 8 ◽  
Author(s):  
Patrick C. A. van der Wel
Keyword(s):  
Solid State ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Structural Information ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Distance Measurements ◽  
Challenges And Opportunities ◽  
Molecule Interactions ◽  
Angle Spinning

In structural studies of immobilized, aggregated and self-assembled biomolecules, solid-state NMR (ssNMR) spectroscopy can provide valuable high-resolution structural information. Among the structural restraints provided by magic angle spinning (MAS) ssNMR the canonical focus is on inter-atomic distance measurements. In the current review, we examine the utility of ssNMR measurements of angular constraints, as a complement to distance-based structure determination. The focus is on direct measurements of angular restraints via the judicious recoupling of multiple anisotropic ssNMR parameters, such as dipolar couplings and chemical shift anisotropies. Recent applications are highlighted, with a focus on studies of nanocrystalline polypeptides, aggregated peptides and proteins, receptor-substrate interactions, and small molecule interactions with amyloid protein fibrils. The review also examines considerations of when and where ssNMR torsion angle experiments are (most) effective, and discusses challenges and opportunities for future applications.

High sensitivity and resolution in 43Ca solid-state NMR experiments

2015 ◽  
Vol 93 (8) ◽  
pp. 799-807 ◽  
Author(s):  
Kevin M.N. Burgess ◽  
Frédéric A. Perras ◽  
Igor L. Moudrakovski ◽  
Yijue Xu ◽  
David L. Bryce
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
High Sensitivity ◽  
Magic Angle Spinning ◽  
Signal Enhancement ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Central Transition ◽  
Angle Spinning

A thorough investigation of solid-state NMR signal enhancement schemes and high-resolution techniques for application to the spin-7/2 43Ca nuclide are presented. Signal enhancement experiments employing double frequency sweeps, hyperbolic secant pulses, and rotor-assisted population transfer, which manipulate the satellite transitions of half-integer quadrupolar nuclei to polarize the central transition (m = + 1/2 ↔ –1/2), are carried out on four well-characterized 43Ca isotopically enriched calcium salts: Ca(NO3)2, Ca(OD)2, CaSO4·2H2O, and Ca(OAc)2·H2O. These results, in conjunction with numerical simulations of 43Ca NMR spectra under magic-angle spinning conditions, are used to identify the technique that provides the most uniform (or quantitative) polarization enhancement as well as the largest signal enhancement factors independent of size of the 43Ca quadrupolar coupling constant, which is the most significant source of resonance broadening in 43Ca NMR spectra. These samples are further investigated using 43Ca double-rotation NMR spectroscopy to yield isotropic, or solution-like, NMR spectra with exquisite resolution. In addition, three unique calcium sites are resolved for the hemihydrated form of calcium acetate (unknown structure), Ca(OAc)2·0.5H2O, with double-rotation NMR, whereas the more common, but more time-consuming, multiple quantum magic-angle spinning technique only clearly resolves two calcium sites. The results shown herein will be useful for other NMR spectroscopists attempting to acquire 43Ca solid-state NMR data for unknown and more complex materials with a higher degree of both sensitivity and resolution.

scholarly journals Frequency-selective Heteronuclear Correlation (FS-HETCOR) Experiments in Solid-State NMR

2021 ◽  
Author(s):  
Zhengfeng Zhang ◽  
Yongchao Su ◽  
Jun Yang
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Structural Information ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Heteronuclear Correlation ◽  
Selective Pulses ◽  
Frequency Selective ◽  
Angle Spinning ◽  
Fast Magic Angle Spinning

Heteronuclear correlation (HETCOR) is critical to obtain structural information in solid-state nuclear magnetic resonance (NMR). We propose novel frequency-selective Heteronuclear correlation (FS-HETCOR) experiments to selectively enhance the inter-atomic correlations of interest. FS-HETCOR relies on heteronuclear selective phase-optimized recoupling (SPRx), which is frequency-selective in heteronuclear recouping without using selective pulses. Compared to regular HETCOR, FS-HETCOR selectively enhances the desired heteronuclear correlations by a factor of up to 5 and suppresses the unwanted ones to 10% as demonstrated in 1H-19F and 1H-13C experiments under fast magic-angle spinning (MAS). Moreover, FS-HETCOR can theoretically be applied at arbitrary MAS rates by utilizing various SPRx schemes. We believe that the method will enhance the ability of solid-state NMR to probe heteronuclear structural information.

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