Reply to Comment on “27Al Multiple-Quantum Magic Angle Spinning NMR Study of the Thermal Transformation between the Microporous Aluminum Methylphosphonates AlMePO-β and AlMePO-α”

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

Canadian Journal of Chemistry ◽

10.1139/cjc-2013-0442 ◽

2014 ◽

Vol 92 (1) ◽

pp. 9-15 ◽

Cited By ~ 11

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.

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

Clay Minerals ◽

10.1180/0009855033840114 ◽

2003 ◽

Vol 38 (4) ◽

pp. 551-559 ◽

Cited By ~ 32

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.

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Solid-state 27Al nuclear magnetic resonance investigation of three aluminum-centered dyes

Canadian Journal of Chemistry ◽

10.1139/v09-155 ◽

2010 ◽

Vol 88 (2) ◽

pp. 111-123 ◽

Cited By ~ 11

Author(s):

Kamal H. Mroué ◽

Abdul-Hamid M. Emwas ◽

William P. Power

Keyword(s):

Solid State ◽

Solid Material ◽

Magic Angle Spinning ◽

Coupling Constants ◽

Magic Angle ◽

Multiple Quantum ◽

Aluminum Phthalocyanine ◽

Nmr Study ◽

Angle Spinning ◽

Nuclear Magnetic

We report the first solid-state 27Al NMR study of three aluminum phthalocyanine dyes: aluminum phthalocyanine chloride, AlPcCl (1); aluminum-1,8,15,22-tetrakis(phenylthio)-29H,31H-phthalocyanine chloride, AlPc(SPh)4Cl (2); and aluminum-2,3-naphthalocyanine chloride, AlNcCl (3). Each of these compounds contains Al3+ ions coordinating to four nitrogen atoms and a chlorine atom. Solid-state 27Al NMR spectra, including multiple-quantum magic-angle spinning (MQMAS) spectra and quadrupolar Carr–Purcell–Meiboom–Gill (QCPMG) spectra of stationary powdered samples have been acquired at multiple high magnetic field strengths (11.7, 14.1, and 21.1 T) to determine their composition and number of aluminum sites, which were analyzed to extract detailed information on the aluminum electric field gradient (EFG) and nuclear magnetic shielding tensors. The quadrupolar parameters for each 27Al site were determined from spectral simulations, with quadrupolar coupling constants (CQ) ranging from 5.40 to 10.0 MHz and asymmetry parameters (η) ranging from 0.10 to 0.50, and compared well with the results of quantum chemical calculations of these tensors. We also report the largest 27Al chemical shielding anisotropy (CSA), with a span of 120 ± 10 ppm, observed directly in a solid material. The combination of MQMAS and computational predictions are used to interpret the presence of multiple aluminum sites in two of the three samples.

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

Inorganic Chemistry ◽

10.1021/acs.inorgchem.8b01034 ◽

2018 ◽

Vol 57 (14) ◽

pp. 8390-8395 ◽

Cited By ~ 3

Author(s):

Bingtian Tu ◽

He Zhang ◽

Hao Wang ◽

Weimin Wang ◽

Zhengyi Fu

Keyword(s):

Magic Angle Spinning ◽

Magic Angle ◽

Nmr Study ◽

Angle Spinning

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

Journal of Materials Chemistry A ◽

10.1039/c6ta04273b ◽

2016 ◽

Vol 4 (34) ◽

pp. 13183-13193 ◽

Cited By ~ 31

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.

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

Canadian Journal of Chemistry ◽

10.1139/v92-159 ◽

1992 ◽

Vol 70 (4) ◽

pp. 1229-1235 ◽

Cited By ~ 8

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.

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