Solid State NMR as A Probe of Inorganic Materials:Examples From Glasses and Sol-Gels

AbstractTo understand amorphous and structurally disordered materials requires the application of a wide-range of advanced physical probe techniques and herein a combined methodology is outlined. The relatively short-range structural sensitivity of solid state NMR means that it is a core probe technique for characterizing such materials. The aspects of the solid state NMR contribution are emphasized here with examples given from a number of systems, with especial emphasis on the information available from 17O NMR in oxygen-containing materials. 17O NMR data for crystallization of pure sol-gel prepared oxides is compared, with new data presented from In2O3 and Sc2O3. Sol-gel formed oxide mixtures containing silica have been widely studied, but again the role and effect of the other added oxide varies widely. In a ternary ZrO2-TiO2-SiO2 silicate sol-gel the level of Q4 formation is dependent not only on the composition, as expected, but also the nature of the second added oxide. Sol-gel formed phosphates have been much less widely studied than silicates and some 31P NMR data from xerogel, sonogel and melt-quench glasses of the same composition are compared. The effect of small amounts of added antibacterial copper on phosphate glass networks is also explored.

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Incorporation of Siloxane And Cyclophosphazene Units Into Metal Oxides by a Nonhydrolytic Sol-Gel Route

MRS Proceedings ◽

10.1557/proc-519-51 ◽

1998 ◽

Vol 519 ◽

Author(s):

L. Crouzet ◽

D. Leclercq ◽

P. H. Mutin ◽

R. J. P. Corriu ◽

A. Vioux

Keyword(s):

Solid State ◽

Metal Oxides ◽

Solid State Nmr ◽

Sol Gel ◽

Gel Method ◽

Sol Gel Method ◽

Nmr Data

AbstractA nonhydrolytic sol-gel method was used to incorporate siloxane and cyclotriphosphazene units within metal oxides. The degree of mixing of the components was investigated by EDX, XPS, and 29Si and 31P solid-state NMR. The NMR data confirmed the presence of Si-O-M and PO- M bonds.

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Solid-State NMR Investigation Of Mixed-Alkali Distribution In Phosphate Glasses

MRS Proceedings ◽

10.1557/proc-658-gg3.20 ◽

2000 ◽

Vol 658 ◽

Cited By ~ 1

Author(s):

S. Prabakar ◽

K.T. Mueller

Keyword(s):

Solid State ◽

Phosphate Glass ◽

Solid State Nmr ◽

Short Range ◽

Double Resonance ◽

Phosphate Glasses ◽

Spatial Proximity ◽

Alkali Cations ◽

Mixed Alkali ◽

O 31

ABSTRACTThe correlation between 31P and 23Na (or 133Cs) nuclei in a mixed-alkali phosphate glass has been investigated by TRAnsfer of Populations by DOuble Resonance (TRAPDOR) NMR spectroscopy. The variation in spatial proximity between 31P nuclei in phosphate tetrahedra and sodium (or cesium) modifier ions has been demonstrated in a phosphate glass with molar composition 25 Cs2O: 31 Na2O: 44P2O5. Interactions between 31P and 23Na (or 133Cs) nuclei are shown to exist even at low dephasing times indicating the short-range nature of these couplings. The ratios of resonance intensities from Q1 and Q2 phosphate units show different trends depending on whether couplings to 23Na or 133Cs are investigated, demonstrating the differing structural roles of the modifier alkali cations within the glass.

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Characterization of nucleosome sediments for protein interaction studies by solid-state NMR spectroscopy

10.5194/mr-2021-21 ◽

2021 ◽

Author(s):

Ulric B. le Paige ◽

ShengQi Xiang ◽

Marco M. R. M. Hendrix ◽

Yi Zhang ◽

Markus Weingarth ◽

...

Keyword(s):

Solid State ◽

Nmr Spectroscopy ◽

Solid State Nmr ◽

Magic Angle Spinning ◽

Magic Angle ◽

Dense Phase ◽

Binding Studies ◽

Nmr Studies ◽

Solid State Nmr Spectroscopy ◽

Wide Range

Abstract. Regulation of DNA-templated processes such as gene transcription and DNA repair depend on the interaction of a wide range of proteins to the nucleosome, the fundamental building block of chromatin. Both solution and solid-state NMR spectroscopy have become an attractive approach to study the dynamics and interactions of nucleosomes, despite their high molecular weight of ~200 kDa. For solid-state NMR (ssNMR) studies, dilute solutions of nucleosomes are converted to a dense phase by sedimentation or precipitation. Since nucleosomes are known to self-associate, these dense phases may induce extensive interactions between nucleosomes, which could interfere with protein binding studies. Here, we characterized the packing of nucleosomes in the dense phase created by sedimentation using NMR and small-angle x-ray scattering (SAXS) experiments. We found that nucleosome sediments are gels with variable degrees of solidity, have nucleosome concentration close to that found in crystals, and are stable for weeks under high-speed magic angle spinning (MAS). Furthermore, SAXS data recorded on recovered sediments indicate that there is no pronounced long-range ordering of nucleosomes in the sediment. Finally, we show that the sedimentation approach can also be used to study low affinity protein interactions with the nucleosome. Together, our results give new insights into the sample characteristics of nucleosome sediments for ssNMR studies and illustrate the broad applicability of sedimentation-based NMR studies.

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Atomic-resolution structure of cytoskeletal bactofilin by solid-state NMR

Science Advances ◽

10.1126/sciadv.1501087 ◽

2015 ◽

Vol 1 (11) ◽

pp. e1501087 ◽

Cited By ~ 39

Author(s):

Chaowei Shi ◽

Pascal Fricke ◽

Lin Lin ◽

Veniamin Chevelkov ◽

Melanie Wegstroth ◽

...

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Caulobacter Crescentus ◽

Heavy Atom ◽

Cytoskeletal Proteins ◽

Atomic Resolution ◽

Hydrophobic Core ◽

X Ray Crystallography ◽

Wide Range ◽

Resolution Structure

Bactofilins are a recently discovered class of cytoskeletal proteins of which no atomic-resolution structure has been reported thus far. The bacterial cytoskeleton plays an essential role in a wide range of processes, including morphogenesis, cell division, and motility. Among the cytoskeletal proteins, the bactofilins are bacteria-specific and do not have a eukaryotic counterpart. The bactofilin BacA of the speciesCaulobacter crescentusis not amenable to study by x-ray crystallography or solution nuclear magnetic resonance (NMR) because of its inherent noncrystallinity and insolubility. We present the atomic structure of BacA calculated from solid-state NMR–derived distance restraints. We show that the core domain of BacA forms a right-handed β helix with six windings and a triangular hydrophobic core. The BacA structure was determined to 1.0 Å precision (heavy-atom root mean square deviation) on the basis of unambiguous restraints derived from four-dimensional (4D) HN-HN and 2D C-C NMR spectra.

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Insight into short-range order, disorder and interfacial interactions in organic semiconductors and their blends through solid-state NMR spectroscopy

10.29363/nanoge.nfasc.2021.003 ◽

2021 ◽

Author(s):

G. N. Manjunatha Reddy

Keyword(s):

Solid State ◽

Nmr Spectroscopy ◽

Organic Semiconductors ◽

Solid State Nmr ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

Interfacial Interactions ◽

Solid State Nmr Spectroscopy ◽

Insight Into

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Solid-State NMR Techniques for the Structural Characterization of Cyclic Aggregates Based on Borane–Phosphane Frustrated Lewis Pairs

Molecules ◽

10.3390/molecules25061400 ◽

2020 ◽

Vol 25 (6) ◽

pp. 1400 ◽

Cited By ~ 1

Author(s):

Robert Knitsch ◽

Melanie Brinkkötter ◽

Thomas Wiegand ◽

Gerald Kehr ◽

Gerhard Erker ◽

...

Keyword(s):

Solid State ◽

Structural Characterization ◽

Solid State Nmr ◽

Magic Angle ◽

Frustrated Lewis Pairs ◽

Wide Range ◽

Nmr Techniques ◽

Nmr Methods ◽

Lewis Pairs

Modern solid-state NMR techniques offer a wide range of opportunities for the structural characterization of frustrated Lewis pairs (FLPs), their aggregates, and the products of cooperative addition reactions at their two Lewis centers. This information is extremely valuable for materials that elude structural characterization by X-ray diffraction because of their nanocrystalline or amorphous character, (pseudo-)polymorphism, or other types of disordering phenomena inherent in the solid state. Aside from simple chemical shift measurements using single-pulse or cross-polarization/magic-angle spinning NMR detection techniques, the availability of advanced multidimensional and double-resonance NMR methods greatly deepened the informational content of these experiments. In particular, methods quantifying the magnetic dipole–dipole interaction strengths and indirect spin–spin interactions prove useful for the measurement of intermolecular association, connectivity, assessment of FLP–ligand distributions, and the stereochemistry of adducts. The present review illustrates several important solid-state NMR methods with some insightful applications to open questions in FLP chemistry, with a particular focus on supramolecular associates.

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Characterization of porous silica gels prepared via the sol-gel process by29Si CP/MAS solid-state NMR spectroscopy

Molecular Physics ◽

10.1080/00268979000102101 ◽

1990 ◽

Vol 71 (4) ◽

pp. 769-780 ◽

Cited By ~ 23

Author(s):

K.L. Walther ◽

A. Wokaun ◽

A. Baiker

Keyword(s):

Solid State ◽

Nmr Spectroscopy ◽

Solid State Nmr ◽

Sol Gel ◽

Porous Silica ◽

Silica Gels ◽

Solid State Nmr Spectroscopy ◽

Sol Gel Process

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Sol–Gel Treatments to Flame Retard PA11/Flax Composites

Fibers ◽

10.3390/fib7100086 ◽

2019 ◽

Vol 7 (10) ◽

pp. 86 ◽

Cited By ~ 1

Author(s):

Samyn ◽

Vandewalle ◽

Bellayer ◽

Duquesne

Keyword(s):

Solid State ◽

Flame Retardant ◽

Solid State Nmr ◽

Flame Retardants ◽

Sol Gel ◽

Deposition Method ◽

One Pot ◽

Successive Layer ◽

Coating Methods ◽

Flame Retardant Properties

This work investigates the efficiency of sol–gel treatments to flame retard flax fabric/PA11 composites. Different sol–gel treatments applied to the flax fabrics were prepared using TEOS in combination with phosphorus and/or nitrogen containing co-precursors (DEPTES, APTES) or additives (OP1230, OP1311). When the nitrogen and the phosphorus co-precursors were used, two coating methods were studied: a ‘one-pot’ route and a successive layer deposition method. For the “one-pot” method, the three precursors (TEOS, DEPTES, and APTES) were mixed together in the same solutions whereas for the different layers deposition method, the three different treatments were deposited on the fibers successively, first the TEOS, then a mix of TEOS/DEPTES, and finally a mix of TEOS/APTES. After deposition, the sol–gel coatings were characterized using scanning electron microscope, electron probe microanalyzer, and 29Si and 31P solid-state NMR. When only TEOS or a mix of TEOS and DEPTES is used, homogeneous coatings are obtained presenting well-condensed Si units (mainly Q units). When APTES is added, the coatings are less homogenous and agglomerates are present. A lower condensation rate of the Si network is also noticed by solid-state NMR. When additives are used in combination with TEOS, the TEOS forms a homogenous and continuous film at the surface of the fibers, but the flame retardants are not well distributed and form aggregates. The flame retardant (FR) efficiency of the different treatments on flax fabrics was evaluated using horizontal flame spread test. The following ranking of the different systems is obtained: TEOS + Additives > TEOS > TEOS + DEPTES ~ TEOS + DEPTES + APTES > multilayers. All the sol–gel coatings improve the flame retardant properties of the flax fabric, except the multilayer treatment. Based on these results, the three most efficient sol–gels were selected to prepare sol–gel-modified flax/PA11 composites. The composite modified with only TEOS showed the best FR properties. Surprisingly, the composite modified with the phosphorus-based flame retardant (AlPi) did not exhibit improved FR properties. This effect was attributed to the fact that the amount of the FR additive deposited on the fabrics was too low.

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