6Li Magic-Angle Spinning (MAS) NMR Study of Electron Correlations, Magnetic Ordering, and Stability of Lithium Manganese(III) Oxides

2000 ◽  
Vol 12 (12) ◽  
pp. 3871-3878 ◽  
Author(s):  
Young Joo Lee ◽  
Clare P. Grey
Keyword(s):  
Magnetic Ordering ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Electron Correlations ◽  
Lithium Manganese ◽  
Nmr Study ◽  
Angle Spinning

scholarly journals 1H HR-MAS NMR Spectroscopy and the Metabolite Determination of Typical Foods in Mediterranean Diet

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Carmelo Corsaro ◽  
Domenico Mallamace ◽  
Sebastiano Vasi ◽  
Vincenzo Ferrantelli ◽  
Giacomo Dugo ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Mediterranean Diet ◽  
Food Product ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Protected Designation Of Origin ◽  
Nmr Study ◽  
Vegetable Foods ◽  
Angle Spinning

NMR spectroscopy has become an experimental technique widely used in food science. The experimental procedures that allow precise and quantitative analysis on different foods are relatively simple. For a better sensitivity and resolution, NMR spectroscopy is usually applied to liquid sample by means of extraction procedures that can be addressed to the observation of particular compounds. For the study of semisolid systems such as intact tissues, High-Resolution Magic Angle Spinning (HR-MAS) has received great attention within the biomedical area and beyond. Metabolic profiling and metabolism changes can be investigated both in animal organs and in foods. In this work we present a proton HR-MAS NMR study on the typical vegetable foods of Mediterranean diet such as the Protected Geographical Indication (PGI) cherry tomato of Pachino, the PGI Interdonato lemon of Messina, several Protected Designation of Origin (PDO) extra virgin olive oils from Sicily, and the Traditional Italian Food Product (PAT) red garlic of Nubia. We were able to identify and quantify the main metabolites within the studied systems that can be used for their characterization and authentication.

A multinuclear MAS NMR study of the short-range structure of fluorophosphate glass

1992 ◽  
Vol 7 (7) ◽  
pp. 1892-1899 ◽  
Author(s):  
R.K. Brow ◽  
Z.A. Osborne ◽  
R.J. Kirkpatrick
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Spectroscopic Studies ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Nmr Studies ◽  
Nmr Study ◽  
Fluorophosphate Glass ◽  
Angle Spinning

We have examined the bonding arrangements in Na–P–O–F and Na–Al–P–O–F glasses using 19F, 27Al, and 31P solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. For the Al-free series of glasses, the 19F NMR spectra are dominated by peaks near +90 ppm, representative of F terminating P-chains. The formation of these bonds has little effect on the 31P chemical shifts, indicating that F preferentially replaces bridging oxygen on the phosphate tetrahedra, consistent with previous NMR studies of crystalline fluorophosphates and other spectroscopic studies of fluorophosphate glass. For the Na–Al–P–O–F glasses, 27Al NMR detects only octahedral Al-sites, the 19F NMR spectra include a second peak near −12 ppm due to F bonded to Al, and the 31P NMR spectra contain signals due to Q1-sites with one or more Al next-nearest neighbors. The relative intensity of the two 19F peaks correlates well with previous spectroscopic studies and shows that a greater fraction of F–P bonds forms when the base glass is remelted in NH4HF2.

Distribution of water in the pores of periodic mesoporous organosilicates – a proton solid state MAS NMR study

2018 ◽  
Vol 20 (46) ◽  
pp. 29351-29361 ◽  
Author(s):  
V. S. Veena ◽  
Kavya Illath ◽  
Anish Lazar ◽  
C. P. Vinod ◽  
T. G. Ajithkumar ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Pore Filling ◽  
Nmr Study ◽  
Proposed Model ◽  
Water Layers ◽  
Angle Spinning

Proposed model of water layers and pore filling in ethane substituted periodic mesoporous organosilicates (PMOE) based on analysis of solid state magic angle spinning (MAS) proton NMR spectra.

29Si and 27Al MAS NMR study of the thermal transformations of kaolinite from North China

Clay Minerals ◽  
2003 ◽  
Vol 38 (4) ◽  
pp. 551-559 ◽  
Author(s):  
H. P. He ◽  
J . G. Guo ◽  
J . X. Zhu ◽  
C. Hu
Keyword(s):  
Nmr Spectra ◽  
Thermal Transformation ◽  
Carbonaceous Material ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Thermal Transformations ◽  
Nmr Study ◽  
27Al Mas Nmr ◽  
Angle Spinning

AbstractThe thermal transformations of kaolinite have been studied using 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR), X-ray diffraction (XRD), differential thermal analysis (DTA) and thermogravimetric analysis (TG). The experimental results show that this sample is a pure kaolinite which contains ∼3% carbonaceous material as impurity. 27Al and 29Si MAS NMR spectra show that the microstructural evolution of the thermal transformation of kaolinite at 450 –1050ºC is similar to that of the kaolinite– mullite reaction series previously published by many authors. 29Si MAS NMR spectra of mullite at 1190 and 1250ºC display two resonances at ∼ – 87 and –92 ppm, corresponding to sillimanite-type geometry around Si and the typical Si environment of mullite, respectively. At 1350ºC, the splitting of (hk0) and (kh0) of mullite occurs, indicating that the primary mullite transforms into orthorhombic mullite. Simultaneously, the resonance at ∼ – 92 ppm splits into two signals at ∼ –90 and –94 ppm. 27Al MAS NMR spectra of the mullite consist of three signals centred at ∼ –4, 45 and 60 ppm, corresponding to octahedral, distorted tetrahedral and tetrahedral Al sites, respectively.

scholarly journals The MAS NMR study of solid solutions based on the YAG crystal

Nukleonika ◽  
2015 ◽  
Vol 60 (3) ◽  
pp. 417-421 ◽  
Author(s):  
Bohdan V. Padlyak ◽  
Nikolaj A. Sergeev ◽  
Marcin Olszewski ◽  
Piotr Stępień
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Solid Solutions ◽  
Yttrium Aluminum Garnet ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Nmr Study ◽  
Yttrium Aluminum ◽  
Angle Spinning

Abstract An 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) study of nominally pure and Cr-doped yttrium-aluminum garnet (Y3Al5O12 and Y3Al5O12:Cr) crystals is reported. It has been shown that the doping by Cr of the Y3Al5O12 crystals leads to the variation of the occupation by Al atoms both octahedrally and tetrahedrally coordinated sites of the garnet lattice.

Magic Angle Spinning NMR Study on Inversion Behavior and Vacancy Disorder in Alumina-Rich Spinel

2018 ◽  
Vol 57 (14) ◽  
pp. 8390-8395 ◽  
Author(s):  
Bingtian Tu ◽  
He Zhang ◽  
Hao Wang ◽  
Weimin Wang ◽  
Zhengyi Fu
Keyword(s):  
Magic Angle Spinning ◽  
Magic Angle ◽  
Nmr Study ◽  
Angle Spinning

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.

scholarly journals Sampling Method Affects HR-MAS NMR Spectra of Healthy Caprine Brain Biopsies

Metabolites ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 38
Author(s):  
Annakatrin Häni ◽  
Gaëlle Diserens ◽  
Anna Oevermann ◽  
Peter Vermathen ◽  
Christina Precht
Keyword(s):  
Nmr Spectroscopy ◽  
Sampling Method ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
1H Nuclear Magnetic Resonance ◽  
Rapid Changes ◽  
Tissue Degradation ◽  
Angle Spinning

The metabolic profiling of tissue biopsies using high-resolution–magic angle spinning (HR-MAS) 1H nuclear magnetic resonance (NMR) spectroscopy may be influenced by experimental factors such as the sampling method. Therefore, we compared the effects of two different sampling methods on the metabolome of brain tissue obtained from the brainstem and thalamus of healthy goats by 1H HR-MAS NMR spectroscopy—in vivo-harvested biopsy by a minimally invasive stereotactic approach compared with postmortem-harvested sample by dissection with a scalpel. Lactate and creatine were elevated, and choline-containing compounds were altered in the postmortem compared to the in vivo-harvested samples, demonstrating rapid changes most likely due to sample ischemia. In addition, in the brainstem samples acetate and inositols, and in the thalamus samples ƴ-aminobutyric acid, were relatively increased postmortem, demonstrating regional differences in tissue degradation. In conclusion, in vivo-harvested brain biopsies show different metabolic alterations compared to postmortem-harvested samples, reflecting less tissue degradation. Sampling method and brain region should be taken into account in the analysis of metabolic profiles. To be as close as possible to the actual situation in the living individual, it is desirable to use brain samples obtained by stereotactic biopsy whenever possible.

Phosphorus-31 chemical shieldings in a fused cis-1,2,3-benzothiadiphosphole: a dipolar NMR study

1992 ◽  
Vol 70 (4) ◽  
pp. 1229-1235 ◽  
Author(s):  
Gang Wu ◽  
Roderick E. Wasylishen ◽  
William P. Power ◽  
Graziano Baccolini
Keyword(s):  
Line Shape ◽  
Magic Angle Spinning ◽  
Pair Approximation ◽  
Magic Angle ◽  
Single Bond ◽  
Chemical Shielding ◽  
Spin Pair ◽  
Nmr Study ◽  
Shielding Tensors ◽  
Angle Spinning

Phosphorus-31 NMR static powder spectra and high-resolution magic angle spinning spectra have been obtained for a new heterocyclic compound, cis-2,10-dimethyl[1,2,3]benzothiadiphospholo[2,3b][1,2,3]benzothiadiphosphole (1), which contains a P(III)—P(III) single bond. The homonuclear 31P–31P dipolar interaction manifests itself in both the magic angle spinning spectra and the non-spinning line shape. Under the AX spin pair approximation, analysis of the spinning sidebands in the MAS experiment yields a full characterization of the two 31P chemical shielding tensors. This approximation is confirmed by the exact powder line shape simulation for a homonuclear spin pair. Analysis of the dipolar subspectra also yields the absolute sign of 1J(P,P), which is found to be negative. Keywords: phosphorus–phosphorus single bond, chemical shielding tensors, dipolar NMR, MAS, static line shape.

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.

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