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Jain SK, Tabassum T, Li L, Ren L, Fan W, Tsapatsis M, Caratzoulas S, Han S, Scott SL. P-Site Structural Diversity and Evolution in a Zeosil Catalyst. J Am Chem Soc 2021; 143:1968-1983. [PMID: 33491456 DOI: 10.1021/jacs.0c11768] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phosphorus-modified siliceous zeolites, or P-zeosils, catalyze the selective dehydration of biomass derivatives to platform chemicals such as p-xylene and 1,3-butadiene. Water generated during these reactions is a critical factor in catalytic activity, but the effects of hydrolysis on the structure, acidity, and distribution of the active sites are largely unknown. In this study, the P-sites in an all-silica self-pillared pentasil (P-SPP) with a low P-loading (Si/P = 27) were identified by solid-state 31P NMR using frequency-selective detection. This technique resolves overlapping signals for P-sites that are covalently bound to the solid phase, as well as oligomers confined in the zeolite but not attached to the zeolite. Dynamic Nuclear Polarization provides the sensitivity necessary to conduct 29Si-filtered 31P detection and 31P-31P correlation experiments. The aforementioned techniques allow us to distinguish sites with P-O-Si linkages from those with P-O-P linkages. The spectra reveal a previously unappreciated diversity of P-sites, including evidence for surface-bound oligomers. In the dry P-zeosil, essentially all P-sites are anchored to the solid phase, including mononuclear sites and dinuclear sites containing the [Si-O-P-O-P-O-Si] motif. The fully-condensed sites evolve rapidly when exposed to humidity, even at room temperature. Partially hydrolyzed species have a wide range of acidities, inferred from their calculated LUMO energies. Initial cleavage of some P-O-Si linkages results in an evolving mixture of surface-bound mono- and oligonuclear P-sites with increased acidity. Subsequent P-O-P cleavage leads to a decrease in acidity as the P-sites are eventually converted to H3PO4. The ability to identify acidic sites in P-zeosils and to describe their structure and stability will play an important role in controlling the activity of microporous catalysts by regulating their water content.
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Affiliation(s)
- Sheetal K Jain
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Tarnuma Tabassum
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Li Li
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Limin Ren
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE, Minneapolis, Minnesota 55455, United States
| | - Wei Fan
- Department of Chemical Engineering, University of Massachusetts Amherst, 686 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Michael Tsapatsis
- Department of Chemical and Biomolecular Engineering and Institute for NanoBiotechnology, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States.,Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Stavros Caratzoulas
- Delaware Energy Institute, 221 Academy Street, Newark, Delaware 19716, United States
| | - Songi Han
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, United States.,Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Susannah L Scott
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, United States.,Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
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Nishida M, Tanaka T, Kanematsu W. Solid-state NMR study on changes of phosphate and proton species in metal pyrophosphate composite (MP 2 O 7 -MO 2 ) ceramics. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:570-578. [PMID: 27862240 DOI: 10.1002/mrc.4552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/28/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
In order to investigate the effects of composite production and the role of the counter cation for metal phosphate conductors, changes in the solid-state nuclear magnetic resonance (NMR) spectra and magnetic relaxation times caused by the removal of volatile products and water washing were examined for various metal pyrophosphate (MP2 O7 -MO2 ; M = Sn, Si, Ti, and Zr). Acidic species could be detected by 1 H MAS NMR spectra for all the composites except ZrP2 O7 -ZrO2 that had the lowest conductivity. The 31 P DD-MAS NMR spectra for MP2 O7 -MO2 composites showed different signal patterns depending on the counter cations participating in the ion exchange as a result of different microstructures. Combinational analysis of 31 P DD-MAS and 31 P CP-MAS NMR spectra of the composites indicated that protonic bulk phosphates were observed at slightly lower fields than non-protonic bulk phosphates in all of the MP2 O7 -MO2 composites. After water washing, the acidic species and the protonic bulk phosphates of MP2 O7 -MO2 composites disappeared or were reduced to trace amounts. The T1 H values of the water-washed composites lengthened because of removal of orthophosphoric acid, although the T1 P values remained almost unchanged. The results of the solid-state NMR studies suggest that the protonic bulk phosphates of MP2 O7 -MO2 composites do not generally distribute in the bulk but exist in the interface between excess H3 PO4 and the bulk. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Masakazu Nishida
- National Institute of Advanced Industrial Science and Technology (AIST), Moriyama-ku, Nagoya, Japan
| | - Tomoko Tanaka
- National Institute of Advanced Industrial Science and Technology (AIST), Moriyama-ku, Nagoya, Japan
| | - Wataru Kanematsu
- National Institute of Advanced Industrial Science and Technology (AIST), Moriyama-ku, Nagoya, Japan
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3
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Development and application of novel NMR methodologies for the in situ characterization of crystallization processes of metastable crystalline materials. ACTA ACUST UNITED AC 2016. [DOI: 10.1515/zkri-2016-1975] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In this contribution we report on the development and application of modern NMR approaches for the in situ characterization of the crystallization of metastable materials. The work was performed within the framework of the DFG priority programme SPP 1415 “Crystalline Non-Equilibrium Phases”. As one of the goals of this project, the development of a NMR methodology which enables an analysis of local structural motifs on short (1–2 Å) and extended (2–6 Å) length scales without the need for fast magic angle spinning (MAS) has been defined, since the enormous centripetal forces which occur during fast sample rotation (up to 107 g) may intervene with the chemical or physical process which is being monitored. To achieve this goal, we developed a magic angle turning probe and pulse sequences allowing to trace the isotropic chemical shifts and heteronuclear dipolar couplings and hence the determination of structural motifs on short and intermediate length scales. With the implementation of novel inductive heating approaches the range of accessible rotation frequencies for in situ high temperature NMR measurements has been enlarged, now covering the ν
MAS range of 0–10 kHz with an accessible temperature of up to 700°C. Application of NMR methodologies for the characterization of crystallization processes and the structure and dynamics of novel phases, partially in joint collaborations within the priority program, are also reported.
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Jmal N, Bouaziz J. Synthesis, characterization and bioactivity of a calcium-phosphate glass-ceramics obtained by the sol-gel processing method. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 71:279-288. [PMID: 27987709 DOI: 10.1016/j.msec.2016.09.058] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 09/06/2016] [Accepted: 09/26/2016] [Indexed: 10/20/2022]
Abstract
In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a mixture of 26.52 in wt.% of fluorapatite (Fap) and 73.48 in wt.% of 77S (77 SiO214 CaO9 P2O5 in wt.%) gel. The calcium phosphate-glass-ceramics was prepared by sol-gel process with tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate and fluorapatite. The synthesized powders were characterized by some commonly used tools such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), 31P magic angle spinning nuclear magnetic resonance (MAS-NMR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thin-film X-ray diffraction (TF-XRD). The obtained results seemed to confirm the nucleation and growth of hydroxyapatite (Hap) nano-phase in the glass. Moreover, an in-vitro evaluation of the glass-ceramic was performed. In addition, to assess its bioactive capacity, it was soaked in simulated body fluid (SBF) at different time intervals. The SEM, EDS and TF-XRD analyses showed the deposition of hydroxyapatite on the surface of the specimens after three days of immersion in SBF solution. The mechanical properties of the obtained material such as rupture strength, Vickers hardness and elastic modulus were measured. In addition, the friction coefficient of calcium phosphate-glass-ceramics was tested. The values of the composite of rupture strength (24MPa), Vickers hardness (214Hv), Young's modulus (52.3GPa), shear modulus (19GPa) and friction coefficient (0.327) were obtained. This glass-ceramics can have useful applications in dental prostheses. Indeed, this material may have promising applications for implants because of its content of fluorine, the effective protector against dental caries.
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Affiliation(s)
- Nouha Jmal
- Laboratory of Industrial Chemistry, National Engineering School of Sfax, Box 1173, 3038 Sfax, University of Sfax, Tunisia.
| | - Jamel Bouaziz
- Laboratory of Industrial Chemistry, National Engineering School of Sfax, Box 1173, 3038 Sfax, University of Sfax, Tunisia
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Bischoff C, Schuller K, Dunlap N, Martin SW. IR, Raman, and NMR studies of the short-range structures of 0.5Na2S + 0.5[xGeS2 + (1-x)PS(5/2)] mixed glass-former glasses. J Phys Chem B 2014; 118:1943-53. [PMID: 24447260 DOI: 10.1021/jp4111053] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A nonlinear and nonadditive composition-dependent change of the ionic conductivity in mixed glass-former (MGF) glasses when one glass former, such as PS(5/2), is replaced by a second glass former, such as GeS2, at constant alkali modifier concentrations, such as Na2S, is known as the mixed glass-former effect (MGFE). Alkali ion conducting glasses are of particular interest for use as solid electrolytes in alkali-based all-solid-state batteries because sulfide amorphous materials have significantly higher alkali ion conductivities than their oxide glass counterparts. In this study of the ternary MGF system Na2S + GeS2 + PS(5/2), we report the careful structural characterization of these glasses using a combination of vibrational, infrared (IR), Raman, and nuclear magnetic resonance (NMR) spectroscopies. Our measurements of the 0.5Na2S + 0.5[xGeS2 + (1-x)PS(5/2)] MGF system show that this glass system exhibits a strongly negative MGFE and non-Arrhenius ionic conductivities. While this negative MGFE in the Na(+) ion conductivity makes these glasses less attractive for use in solid-state Na batteries, the structural origin of this effect is important to better understand the mechanisms of ion conduction in the glassy state. For these reasons, we have examined the structures of ternary 0.5Na2S + 0.5[xGeS2 + (1-x)PS(5/2)] glasses using Raman, IR, and (31)P MAS NMR spectroscopies. In these studies, it is found that the substitution of PS(5/2) by GeS2, that is, increasing x, leads to unequal sharing of the Na(+) in these glasses. Thus, in all MGF compositions, phosphorus groups are associated with a disproportionately larger fraction, f(Na(P)) > 0.5(1 - x), of the Na(+) ions while the germanium groups are found to be Na(+)-deficient relative to the total amount of Na(+) present in the glass, that is, f(Na(Ge)) < 0.5x. From the spectroscopic study of these glasses, a short-range order (SRO) structural model is developed for these glasses and is based on the germanium and phosphorus SRO groups in these glasses as a first step in understanding the unique negative MGFE and non-Arrhenius behavior in the Na(+) ion conductivity in these glasses.
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Affiliation(s)
- Christian Bischoff
- Department of Materials Science and Engineering, Iowa State University of Science & Technology , Ames, Iowa 50011, United States
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Massiot D, Messinger RJ, Cadars S, Deschamps M, Montouillout V, Pellerin N, Veron E, Allix M, Florian P, Fayon F. Topological, geometric, and chemical order in materials: insights from solid-state NMR. Acc Chem Res 2013; 46:1975-84. [PMID: 23883113 DOI: 10.1021/ar3003255] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Unlike the long-range order of ideal crystalline structures, local order is an intrinsic characteristic of real materials and often serves as the key to the tuning of their properties and their final applications. Although researchers can easily assess local ordering using two-dimensional imaging techniques with resolution that approaches the atomic level, the diagnosis, description, and qualification of local order in three dimensions is much more challenging. Solid-state nuclear magnetic resonance (NMR) and its panel of continually developing instruments and methods enable the local, atom-selective characterization of structures and assemblies ranging from the atomic to the nanometer length scales. By making use of the indirect J-coupling that distinguishes chemical bonds, researchers can use solid-state NMR to characterize a variety of materials, ranging from crystalline compounds to amorphous or glassy materials. In crystalline compounds showing some disorder, we describe and distinguish the contributions of topology, geometry, and local chemistry in ways that are consistent with X-ray diffraction and computational approaches. We give examples of materials featuring either chemical disorder in a topological order or topological disorder with local chemical order. For glasses, we show that we can separate geometric and chemical contributions to the local order by identifying structural motifs with a viewpoint that extends from the atomic scale up to the nanoscale. As identified by solid state NMR, the local structure of amorphous materials or glasses consists of well-identified structural entities up to at least the nanometer scale. Instead of speaking of disorder, we propose a new description for these structures as a continuous assembly of locally defined structures, an idea that draws on the concept of locally favored structures (LFS) introduced by Tanaka and coworkers. This idea provides a comprehensive picture of amorphous structures based on fluctuations of chemical composition and structure over different length scales. We hope that these local or molecular insights will allow researchers to consider key questions related to nucleation and crystallization, as well as chemically (spinodal decomposition) or density-driven (polyamorphism) phase separation, which could lead to future applications in a variety of materials.
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Affiliation(s)
- Dominique Massiot
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - Robert J. Messinger
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - Sylvian Cadars
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - MichaËl Deschamps
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - Valerie Montouillout
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - Nadia Pellerin
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - Emmanuel Veron
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - Mathieu Allix
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - Pierre Florian
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
| | - Franck Fayon
- CNRS, CEMHTI, UPR 3079, F-45071, Orléans, France, and University of Orléans, CEMHTI, UPR CNRS 3079, F-45071, Orléans, France
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Charpentier T, Menziani MC, Pedone A. Computational simulations of solid state NMR spectra: a new era in structure determination of oxide glasses. RSC Adv 2013. [DOI: 10.1039/c3ra40627j] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Larink D, Ren J, Eckert H. Spectral editing based on scalar spin-spin interactions: new results on the structure of metathiophosphate glasses. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 45-46:30-35. [PMID: 22664187 DOI: 10.1016/j.ssnmr.2012.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/09/2012] [Indexed: 06/01/2023]
Abstract
The local structure of glassy NaPS(3) and AgPS(3) was analyzed based on quantitative (31)P MAS-NMR spectroscopy. The glasses contain some oxide impurities, which could be quantified from the NMR spectral analysis. Four discrete resonances are observed in both glasses, which were assigned to four distinct types of phosphate groups P((n)), where n is the number of P-S-P bridges(i.e., P((0)), P((1)), P((2)), and P((3)) units, respectively) with the help of 2D homonuclear J-resolved and INADEQUATE methods. Based on the results obtained, the interpretations of previous spectra obtained at low spinning speeds on lithium and silver thiophosphate glasses (Chem. Mater. 2 (1990), 273, and J. Am. Chem. Soc. 114 (1992), 5775) need to be revised. Contrary to the situation in alkali phosphate glasses, the corresponding sulfide analogs are characterized by a wide P((n)) species distribution close to that predicted by a statistical charge distribution. INADEQUATE experiments fail to detect P((n))-P((n-1)) connectivities, suggesting that the structure of these glasses is rather inhomogeneous, possibly featuring the different P((n)) species in segregated domains.
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Affiliation(s)
- Dirk Larink
- Institut für Physikalische Chemie, WWU Münster, Münster, Germany
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Hemme WL, Fujita W, Awaga K, Eckert H. Solid state NMR strategies for the structural characterization of new hybrid materials based on the intercalation of nitroxide radicals into CdPS3. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2011; 39:106-115. [PMID: 21543192 DOI: 10.1016/j.ssnmr.2011.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Indexed: 05/30/2023]
Abstract
The radical cations 2-(3-N-butylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-N-oxide (m-BuPYNN) and 4-(ethylammonium)-2,2,6,6-tetramethylpiperidin-1-oxide (EATEP) are successfully intercalated into the layered host structure of CdPS(3) via ion exchange. The reaction proceeds either directly from ethanolic solutions of the radical iodide salt or via a two-stage process involving first the formation of an intermediate tetramethylammonium intercalate. The resulting materials, which are described by the compositional formula Cd(1-x)PS(3){Rad}(2x), are characterized by chemical analysis, X-ray powder diffraction, bulk susceptibility measurements and EPR spectroscopy. Modern single and double resonance solid state NMR techniques are introduced successfully to study the structural modifications of the host lattice and the details of the intermolecular guest/host interactions. (1)H MAS-NMR spectra reveal substantial differences in the unpaired electron spin density distributions within the radical ions intercalated into the host lattice compared to those obtained for the pure radical ion salts, leading to different bulk magnetic properties. The results of (1)H/(31)P double resonance experiments indicate that the orientation of the guest molecules is dominated by Columbic interactions between the radical cations and the negatively charged cadmium vacancies in the host lattice.
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Affiliation(s)
- Wilhelm L Hemme
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität, Corrensstrasse 30, 48149 Münster, Germany
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Slater C, Laurencin D, Burnell V, Smith ME, Grover LM, Hriljac JA, Wright AJ. Enhanced stability and local structure in biologically relevant amorphous materials containing pyrophosphate. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm13930d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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11
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Xue X. Determination of J coupling constants between spin-1/2 and quadrupolar nuclei in inorganic solids from spin echo and refocused INEPT experiments: a case study on AlPO₄ berlinite. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2010; 38:62-73. [PMID: 21030218 DOI: 10.1016/j.ssnmr.2010.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 08/02/2010] [Accepted: 09/14/2010] [Indexed: 05/30/2023]
Abstract
A systematic study utilizing rotor-synchronized homonuclear ((31)P, (27)Al) and heteronuclear ({(31)P}(27)Al and {(27)Al}(31)P) spin echo, and {(27)Al}(31)P refocused INEPT experiments (employing soft pulses for selective excitation of the central transition for the quadrupolar (27)Al (I=5/2)) have been performed on AlPO(4) berlinite at 30 kHz MAS to better understand the J modulation behavior involving half-integer quadrupolar nuclei in solid materials with framework structure. Analyses of the J modulation on either the (27)Al or (31)P coherence in both the {(31)P}(27)Al and {(27)Al}(31)P spin echo experiments, and both periods of the refocused INEPT experiment yield consistent results for the (2)J(AlP) (Al-O-P) coupling constant (ca. 25 Hz). It is noted that the coupling of each (27)Al to four (31)P spins during the first ((27)Al) evolution period of the refocused INEPT, and the populations of (31)P coupled to different numbers (0-4) of (27)Al in the ± 1/2 Zeeman states during (31)P coherence evolution, which have been neglected in previous studies, must be taken into account for proper treatment. Analysis of J modulation on the spin ((27)Al) coupled to spin-1/2 nuclei in general gives more accurate results. Weak long-range homonuclear (4)J(PP) (P-O-Al-O-P) coupling was also observed from the (31)P spin echo and INADEQUATE experiments.
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Affiliation(s)
- Xianyu Xue
- Institute for Study of the Earth's Interior, Okayama University, Yamada 827, Misasa, Tottori 682-0193, Japan.
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12
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Solid-State Nuclear Magnetic Resonance Spectroscopy: A Review of Modern Techniques and Applications for Inorganic Polymers. J Inorg Organomet Polym Mater 2010. [DOI: 10.1007/s10904-010-9358-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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13
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Massiot D, Fayon F, Deschamps M, Cadars S, Florian P, Montouillout V, Pellerin N, Hiet J, Rakhmatullin A, Bessada C. Detection and use of small J couplings in solid state NMR experiments. CR CHIM 2010. [DOI: 10.1016/j.crci.2009.05.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Hemme WL, Fujita W, Awaga K, Eckert H. Intercalation of stable organic radicals into layered inorganic host matrices: Preparation and structural characterization of Cd1−xPS3(metaMPYNN)2x. J SOLID STATE CHEM 2009. [DOI: 10.1016/j.jssc.2009.09.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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Tian Y, Chen L, Niks D, Kaiser JM, Lai J, Rienstra CM, Dunn MF, Mueller LJ. J-Based 3D sidechain correlation in solid-state proteins. Phys Chem Chem Phys 2009; 11:7078-86. [PMID: 19652843 PMCID: PMC2798598 DOI: 10.1039/b911570f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Scalar-based three-dimensional homonuclear correlation experiments are reported for (13)C sidechain correlation in solid-state proteins. These experiments are based on a sensitive constant-time format, in which homonuclear scalar couplings are utilized for polarization transfer, but decoupled during chemical shift evolution, to yield highly resolved indirect dimensions and band selectivity as desired. The methods therefore yield spectra of high quality that give unique sets of sidechain correlations for small proteins even at 9.4 Tesla (400 MHz (1)H frequency). We demonstrate versions of the pulse sequence that enable correlation from the sidechain to the backbone carbonyl as well as purely sidechain correlation sets; together these two data sets provide the majority of (13)C-(13)C correlations for assignment. The polarization transfer efficiency is approximately 30% over two bonds. In the protein GB1 (56 residues), we find essentially all cross peaks uniquely resolved. We find similar efficiency of transfer (approximately 30%) in the 140 kDa tryptophan synthase (TS), since the relaxation rates of immobilized solid proteins are not sensitive to global molecular tumbling, as long as the correlation time is much longer than the magic-angle spinning rotor period. In 3D data sets of TS at 400 MHz, some peaks are resolved and, in combination with higher field data sets, we anticipate that assignments will be possible; in this vein, we demonstrate 2D (13)C-(13)C spectra of TS at 900 MHz that are well resolved. These results together provide optimism about the prospects for assigning the spectra of such large enzymes in the solid state.
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Affiliation(s)
- Ye Tian
- Department of Chemistry, University of California, Riverside, California 92521
| | - Lingling Chen
- Department of Chemistry, University of California, Riverside, California 92521
| | - Dimitri Niks
- Department of Biochemistry, University of California, Riverside, California 92521
| | - J. Michael Kaiser
- Department of Chemistry, University of California, Riverside, California 92521
| | - Jinfeng Lai
- Department of Chemistry, University of California, Riverside, California 92521
| | - Chad M. Rienstra
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Michael F. Dunn
- Department of Biochemistry, University of California, Riverside, California 92521
| | - Leonard J. Mueller
- Department of Chemistry, University of California, Riverside, California 92521
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Guerry P, Smith ME, Brown SP. 31P MAS Refocused INADEQUATE Spin−Echo (REINE) NMR Spectroscopy: Revealing J Coupling and Chemical Shift Two-Dimensional Correlations in Disordered Solids. J Am Chem Soc 2009; 131:11861-74. [DOI: 10.1021/ja902238s] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul Guerry
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Mark E. Smith
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Steven P. Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
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Brown SP. Recent Advances in Solid-State MAS NMR Methodology for Probing Structure and Dynamics in Polymeric and Supramolecular Systems. Macromol Rapid Commun 2009; 30:688-716. [DOI: 10.1002/marc.200800816] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 02/06/2009] [Indexed: 01/12/2023]
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18
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Cadars S, Brouwer DH, Chmelka BF. Probing local structures of siliceous zeolite frameworks by solid-state NMR and first-principles calculations of 29Si–O–29Si scalar couplings. Phys Chem Chem Phys 2009; 11:1825-37. [DOI: 10.1039/b815361b] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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19
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Joyce SA, Yates JR, Pickard CJ, Brown SP. Density Functional Theory Calculations of Hydrogen-Bond-Mediated NMR J Coupling in the Solid State. J Am Chem Soc 2008; 130:12663-70. [DOI: 10.1021/ja800419m] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Siân A. Joyce
- Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland, TCM Group, Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, U.K., School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, U.K., and Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Jonathan R. Yates
- Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland, TCM Group, Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, U.K., School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, U.K., and Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Chris J. Pickard
- Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland, TCM Group, Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, U.K., School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, U.K., and Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Steven P. Brown
- Tyndall National Institute, Lee Maltings, Prospect Row, Cork, Ireland, TCM Group, Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 OHE, U.K., School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, U.K., and Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
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20
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O’Dell LA, Guerry P, Wong A, Abou Neel EA, Pham TN, Knowles JC, Brown SP, Smith ME. Quantification of crystalline phases and measurement of phosphate chain lengths in a mixed phase sample by 31P refocused INADEQUATE MAS NMR. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.02.070] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Martin RA, Salmon PS, Carroll DL, Smith ME, Hannon AC. Structure and thermal properties of yttrium alumino-phosphate glasses. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:115204. [PMID: 21694221 DOI: 10.1088/0953-8984/20/11/115204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The structure and thermal properties of yttrium alumino-phosphate glasses, of nominal composition (Y(2)O(3))(0.31-z)(Al(2)O(3))(z)(P(2)O(5))(0.69) with [Formula: see text], were studied by using a combination of neutron diffraction, (27)Al and (31)P magic angle spinning nuclear magnetic resonance, differential scanning calorimetry and thermal gravimetric analysis methods. The Vickers hardness of the glasses was also measured. The data are compared to those obtained for pseudo-binary Al(2)O(3)-P(2)O(5) glasses and the structure of all these materials is rationalized in terms of a generic model for vitreous phosphate materials in which Y(3+) and Al(3+) act as modifying cations that bind only to the terminal (non-bridging) oxygen atoms of PO(4) tetrahedra. The results are used to help elucidate the phenomenon of rare-earth clustering in phosphate glasses which can be reduced by substituting Al(3+) ions for rare-earth R(3+) ions at fixed modifier content.
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22
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Griffin JM, Tripon C, Samoson A, Filip C, Brown SP. Low-load rotor-synchronised Hahn-echo pulse train (RS-HEPT) 1H decoupling in solid-state NMR: factors affecting MAS spin-echo dephasing times. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2007; 45 Suppl 1:S198-S208. [PMID: 18098353 DOI: 10.1002/mrc.2145] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Transverse dephasing times T(2)' in spin-echo MAS NMR using rotor-synchronised Hahn-echo pulse-train (RS-HEPT) low-load (1)H decoupling are evaluated. Experiments were performed at 300 and 600 MHz for (13)CH-labelled L-alanine and (15)NH(delta)-labelled L-histidine.HCl.H(2)O, together with SPINEVOLUTION simulations for a ten-spin system representing the crystal structure environment of the (13)CH carbon in L-alanine. For 30 kHz MAS and nu(1)((1)H) = 100 kHz at 300 MHz, a RS-HEPT T(2)' value of 17 +/- 1 ms was obtained for (13)CH-labelled L-alanine which is approximately 50% of the XiX T(2)' value of 33 +/- 2 ms. Optimum RS-HEPT decoupling performance is observed for a relative phase of alternate RS-HEPT pi-pulses, Deltaphi = phi'- phi, between 40 and 60 degrees . For experiments at 600 MHz and 30 kHz MAS with (13)CH-labelled L-alanine, the best RS-HEPT (nu(1)((1)H) = 100 kHz) T(2)' value was 3 times longer than that observed for low-power continuously applied sequences with nu(1)((1)H) < or =40 kHz, i.e. corresponding to the same average power dissipated in the probe. A marked improvement in RS-HEPT (1)H decoupling is observed for increasing MAS frequency: at 55.6 kHz MAS, a best RS-HEPT T(2)' value of 34 +/- 5 ms was recorded for (13)CH-labelled L-alanine. Much improved RS-HEPT broadband performance was also observed at 55.6 kHz MAS as compared to 30 kHz MAS.
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Affiliation(s)
- John M Griffin
- Department of Physics, University of Warwick, Coventry, UK
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23
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Rinke MT, Zhang L, Eckert H. Structural integration of tellurium oxide into mixed-network-former glasses: connectivity distribution in the system NaPO(3)-TeO(2). Chemphyschem 2007; 8:1988-98. [PMID: 17726674 DOI: 10.1002/cphc.200700358] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Sodium phosphate tellurite glasses in the system (NaPO(3))(x)(TeO(2))(1-) (x) were prepared and structurally characterized by thermal analysis, vibrational spectroscopy, X-ray photoelectron spectroscopy (XPS) and a variety of complementary solid-state nuclear magnetic resonance (NMR) techniques. Unlike the situation in other mixed-network-former glasses, the interaction between the two network formers tellurium oxide and phosphorus oxide produces no new structural units, and no sharing of the network modifier Na(2)O takes place. The glass structure can be regarded as a network of interlinked metaphosphate-type P(2) tetrahedral and TeO(4/2) antiprismatic units. The combined interpretation of the O 1s XPS data and the (31)P solid-state NMR spectra presents clear quantitative evidence for a nonstatistical connectivity distribution. Rather, the formation of homoatomic P--O--P and Te--O--Te linkages is favored over mixed P--O--Te connectivities. As a consequence of this chemical segregation effect, the spatial sodium distribution is not random, as also indicated by a detailed analysis of (31)P/(23)Na rotational echo double-resonance (REDOR) experiments.
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Affiliation(s)
- Matthias T Rinke
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
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24
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van Wüllen L, Tricot G, Wegner S. An advanced NMR protocol for the structural characterization of aluminophosphate glasses. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2007; 32:44-52. [PMID: 17706927 DOI: 10.1016/j.ssnmr.2007.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 06/28/2007] [Accepted: 07/09/2007] [Indexed: 05/16/2023]
Abstract
In this work a combination of complementary advanced solid-state nuclear magnetic resonance (NMR) strategies is employed to analyse the network organization in aluminophosphate glasses to an unprecedented level of detailed insight. The combined results from MAS, MQMAS and (31)P-{(27)Al}-CP-heteronuclear correlation spectroscopy (HETCOR) NMR experiments allow for a detailed speciation of the different phosphate and aluminate species present in the glass. The interconnection of these local building units to an extended three-dimensional network is explored employing heteronuclear dipolar and scalar NMR approaches to quantify P-O-Al connectivity by (31)P{(27)Al}-heteronuclear multiple quantum coherence (HMQC), -rotational echo adiabatic passage double resonance (REAPDOR) and -HETCOR NMR as well as (27)Al{(31)P}-rotational echo double resonance (REDOR) NMR experiments, complemented by (31)P-2D-J-RESolved MAS NMR experiments to probe P-O-P connectivity utilizing the through bond scalar J-coupling. The combination of the results from the various NMR approaches enables us to not only quantify the phosphate units present in the glass but also to identify their respective structural environments within the three-dimensional network on a medium length scale employing a modified Q notation, Q(n)(m),(AlO)(x), where n denotes the number of connected tetrahedral phosphate, m gives the number of aluminate species connected to a central phosphate unit and x specifies the nature of the bonded aluminate species (i.e. 4, 5 or 6 coordinate aluminium).
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Affiliation(s)
- Leo van Wüllen
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Correnstrasse 30-36, 48149 Münster, Germany.
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25
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Cadars S, Sein J, Duma L, Lesage A, Pham TN, Baltisberger JH, Brown SP, Emsley L. The refocused INADEQUATE MAS NMR experiment in multiple spin-systems: interpreting observed correlation peaks and optimising lineshapes. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 188:24-34. [PMID: 17588789 DOI: 10.1016/j.jmr.2007.05.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Accepted: 05/18/2007] [Indexed: 05/12/2023]
Abstract
The robustness of the refocused INADEQUATE MAS NMR pulse sequence for probing through-bond connectivities has been demonstrated in a large range of solid-state applications. This pulse sequence nevertheless suffers from artifacts when applied to multispin systems, e.g. uniformly labeled (13)C solids, which distort the lineshapes and can potentially result in misleading correlation peaks. In this paper, we present a detailed account that combines product-operator analysis, numerical simulations and experiments of the behavior of a three-spin system during the refocused INADEQUATE pulse sequence. The origin of undesired anti-phase contributions to the spectral lineshapes are described, and we show that they do not interfere with the observation of long-range correlations (e.g. two-bond (13)C-(13)C correlations). The suppression of undesired contributions to the refocused INADEQUATE spectra is shown to require the removal of zero-quantum coherences within a z-filter. A method is proposed to eliminate zero-quantum coherences through dephasing by heteronuclear dipolar couplings, which leads to pure in-phase spectra.
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Affiliation(s)
- Sylvian Cadars
- Laboratoire de Chimie (UMR 5182 CNRS/ENS Lyon), Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
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26
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Santagneli SH, de Araujo CC, Strojek W, Eckert H, Poirier G, Ribeiro SJL, Messaddeq Y. Structural Studies of NaPO3−MoO3 Glasses by Solid-State Nuclear Magnetic Resonance and Raman Spectroscopy. J Phys Chem B 2007; 111:10109-17. [PMID: 17683136 DOI: 10.1021/jp072883n] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vitreous samples were prepared in the (100 - x)% NaPO(3)-x% MoO(3) (0 <or= x <or= 70) glass-forming system by a modified melt method that allowed good optical quality samples to be obtained. The structural evolution of the vitreous network was monitored as a function of composition by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), Raman scattering, and solid-state nuclear magnetic resonance (NMR) for (31)P, (23)Na, and (95)Mo nuclei. Addition of MoO(3) to the NaPO(3) glass melt leads to a pronounced increase in the glass transition temperatures up to x = 45, suggesting a significant increase in network connectivity. For this same composition range, vibrational spectra suggest that the Mo(6+) ions are bonded to some nonbridging oxygen atoms (Mo-O- or Mo=O bonded species). Mo-O-Mo bond formation occurs only at MoO(3) contents exceeding x = 45. (31)P magic-angle spinning (MAS) NMR spectra, supported by two-dimensional J-resolved spectroscopy, allow a clear distinction between species having two, one, and zero P-O-P linkages. These sites are denoted as Q(2)(2Mo), Q(2)(1Mo), and Q(2)(0Mo), respectively. For x < 0.45, the populations of these sites can be described along the lines of a binary model, according to which each unit of MoO(3) converts two Q(2)(nMo) sites into two Q(2)((n+1)Mo) sites (n = 0, 1). This structural model is consistent with the presence of tetrahedral Mo(=O)2(O(1/2))2 environments. Indeed, (95)Mo NMR data suggest that the majority of the molybdenum species are four-coordinated. However, the presence of additional six-coordinate molybdenum in the MAS NMR spectra indicates that the structure of these glasses may be more complicated and may additionally involve sharing of network modifier oxide between the network formers phosphorus and molybdenum. This latter hypothesis is further supported by (23)Na{(31)P} rotational echo double resonance (REDOR) data, which clearly reveal that the magnetic dipole-dipole interactions between (31)P and (23)Na are increasingly diminished with increasing molybdenum content. The partial transfer of modifier from the phosphate to the molybdate network former implies a partial repolymerization of the phosphate species, resulting in the formation of Q(3)(nMo) species and accounting for the observed increase in the glass transition temperature with increasing MoO(3) content that is observed in the composition range 0 <or= x <or= 45. Glasses with MoO(3) contents beyond x = 45 show decreased thermal and crystallization stability. Their structure is characterized by isolated phosphate species [most likely of the P(OMo)4 type] and molybdenum oxide clusters with a large extent of Mo-O-Mo connectivity.
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Affiliation(s)
- Silvia H Santagneli
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, D-48149 Münster, Germany
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27
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Hu B, Amoureux JP, Trebosc J. Indirect covariance NMR spectroscopy of through-bond homo-nuclear correlations for quadrupolar nuclei in solids under high-resolution. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2007; 31:163-8. [PMID: 17537617 DOI: 10.1016/j.ssnmr.2007.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 02/26/2007] [Accepted: 03/27/2007] [Indexed: 05/15/2023]
Abstract
Indirect covariance NMR spectroscopy is demonstrated in solids, and we show that it can be used to obtain through-bond 2D homo-nuclear correlation spectra for quadrupolar nuclei under high-resolution. These spectra, generated with indirect covariance from a hetero-nuclear correlation spectrum, are equivalent to those recorded with the through-bond homo-nuclear hetero-nuclear single-quantum correlation (H-HSQC) method very recently proposed. However, the indirect covariance method can save a lot of experiment time, compared to the H-HSQC experiments, which allows introducing a high-resolution quadrupolar filter, thus providing a much better resolution, even on medium-field spectrometers. The covariance concept can be used to generate many different "indirectly-detected" high-resolution homo-nuclear correlation spectra with through-space or through-bond correlations for spin 1/2 or quadrupolar nuclei. We also propose a simple method that decreases the noise in all (direct or indirect) covariance methods.
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Affiliation(s)
- Bingwen Hu
- UCCS, CNRS-8181, Lille University, FR-59652 Villeneuve d'Ascq, France
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28
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Othman A, Evans JSO, Evans IR, Harris RK, Hodgkinson P. Structural Study of Polymorphs and Solvates of Finasteride. J Pharm Sci 2007; 96:1380-97. [PMID: 17455354 DOI: 10.1002/jps.20940] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
NMR and XRD data are reported for several new forms of finasteride, including the results of complete structure determinations for three solvates. Form III of finasteride, hitherto only mentioned in the patent literature, and a new anhydrous form designated Form X, have been found in mixtures of polymorphs and their (13)C NMR chemical shifts obtained. The results demonstrate that the crystallographic asymmetric units contain three molecules and one molecule, respectively. Attempts to reproduce "Form H1", as described in a patent, resulted in a new IPA solvate hydrate. The previously-reported acetic acid, dioxane, and ethyl acetate solvates have been further characterised, and new THF and diethyl ether solvates prepared and characterised. The crystal structures of the dioxane, IPA, and THF solvates have been determined by single-crystal X-ray diffraction. All the solvates (except the acetic acid case) are found to be hemihydrates, to have a finasteride: solvent molar ratio of 2:1 and to have a common structure. The solvate molecules are highly disordered and sited in channels in the structure. The powder XRD patterns are characteristic of the common structure. These solvates may be distinguished by the characteristic CPMAS (13)C signals from the solvent molecules, but the resonances of the host finasteride structures differ only marginally, and powder XRD patterns are almost indistinguishable. Magic-angle spinning (MAS) proton spectra give sharp lines for the solvent peaks, confirming their high degree of mobility. This is further shown in one case by direct polarisation (13)C spectra. Mobility of the tert-butyl group is also implied. Thermal characteristics have been studied and TGA used (in conjunction with solution-state proton NMR) to estimate molar ratios.
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Affiliation(s)
- Abdullah Othman
- Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, UK
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29
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Iuga A, Iuga D, Cross AR, Gerken M, Hazendonk P. Observation of satellite signals due to scalar coupling to spin-1/2 isotopes in solid-state nuclear magnetic resonance spectroscopy. J Chem Phys 2007; 126:054305. [PMID: 17302475 DOI: 10.1063/1.2432122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A method is introduced to select the signal from a spin-1/2 nucleus I specifically bound to another spin-1/2 nucleus S for solid-state magic angle spinning nuclear magnetic resonance (NMR) spectroscopy via correlation through the heteronuclear J coupling. This experiment is analogous to the bilinear rotation decoupling (BIRD) sequence in liquid-state NMR spectroscopy which selects for signals from 1H directly bound to 13C. The spin dynamics of this modified BIRD experiment is described using the product-operator formalism, where experimental considerations such as rotor synchronization and the effect of large chemical shielding anisotropies on I and S are discussed. Two experiments are proposed that accommodate large chemical shielding anisotropies on S: (1) by stepping the inversion pulse frequency through the entire S spectral range or (2) by adiabatically inverting the S spins. Both these experiments are shown to successfully select the signal of 19F bound to 129Xe in XeF+ salts, removing the contributions from isotopomers containing non-spin-1/2 Xe isotopes. The feasibility in obtaining isotope-selective 19F spectra of inorganic fluoride compounds is discussed, and further modifications are proposed to expand the application to other chemical systems.
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Affiliation(s)
- Adriana Iuga
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada
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30
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Coelho C, Azaïs T, Bonhomme-Coury L, Laurent G, Bonhomme C. Efficiency of the Refocused31P−29Si MAS-J-INEPT NMR Experiment for the Characterization of Silicophosphate Crystalline Phases and Amorphous Gels. Inorg Chem 2007; 46:1379-87. [PMID: 17291123 DOI: 10.1021/ic061964f] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One- and two-dimensional refocused MAS-J-INEPT NMR experiments in the solid state (through-bond polarization transfer) involving the highly abundant 31P spin and the rare 29Si spin are described for the crystalline silicophosphate phase Si5O(PO4)6 and complex mixtures of SiP2O7 polymorphs. The evaluation of the 2JP-O-Si coupling constants for all 29Si sites is obtained by the careful analysis of the INEPT build-up curves under fast MAS. The results are in agreement with the crystallographic data, taking into account the various J coupling paths. The efficiency of the experiment is demonstrated by its application to more complex systems such as silicophosphate amorphous gels (obtained by the sol-gel process).
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Affiliation(s)
- C Coelho
- Université Pierre et Marie Curie-Paris 6, UMR 7574, Laboratoire Chimie de la Matière Condensée de Paris, Paris, F-75005 France
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31
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Pham TN, Griffin JM, Masiero S, Lena S, Gottarelli G, Hodgkinson P, Filip C, Brown SP. Quantifying hydrogen-bonding strength: the measurement of 2hJNN couplings in self-assembled guanosines by solid-state 15N spin-echo MAS NMR. Phys Chem Chem Phys 2007; 9:3416-23. [PMID: 17664965 DOI: 10.1039/b703513f] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
(2h)J(NN) hydrogen-bond mediated J couplings are measured in the solid state for two synthetic deoxyguanosine derivatives by (15)N MAS NMR spin-echo experiments. The use of rotor-synchronised Hahn-echo pulse train (RS-HEPT) (1)H decoupling, with a duty cycle of 6%, allows spin-echo durations out to 200 ms, hence enabling the accurate determination of J couplings as small as 3.8 Hz. A single-crystal X-ray diffraction structure exists for the shorter alkyl chain derivative dG(C(3))(2): the observation of significantly different (2h)J(NN) couplings, 6.2 +/- 0.4 and 7.4 +/- 0.4 Hz, for the two resolved N7 resonances is to be expected given the NH...N hydrogen-bonding distances of 2.91 and 2.83 A for the two distinct molecules in the asymmetric unit cell. For the longer alkyl chain derivative, dG(C(10))(2), for which there is no single-crystal diffraction structure, a (15)N refocused INADEQUATE spectrum (Pham et al., J. Am. Chem. Soc., 2005, 127, 16018-16019) has demonstrated the presence of N2-H...N7 intermolecular hydrogen-bonds indicative of a quartet-like structure. The (2h)J(NN) hydrogen-bond mediated J coupling of 5.9 +/- 0.2 Hz is at the lower end of the range (5.9-8.2 Hz) of (2h)J(NN) couplings determined from solution-state NMR of guanosine quartets in quadruplex DNA. A full discussion of the determination of error bars on the fitted parameters is given; specifically, error bars determined by a non-linear fitting (using the covariance matrix) or in a Monte-Carlo fashion are found to give effectively identical results.
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Affiliation(s)
- Tran N Pham
- Department of Physics, University of Warwick, Coventry, UK CV4 7AL
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32
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Martineau C, Fayon F, Legein C, Buzaré JY, Silly G, Massiot D. Accurate heteronuclear J-coupling measurements in dilute spin systems using the multiple-quantum filtered J-resolved experiment. Chem Commun (Camb) 2007:2720-2. [PMID: 17594032 DOI: 10.1039/b703321d] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new solid-state MAS NMR experiment is proposed to accurately measure heteronuclear (19)F-(207)Pb J-coupling constants, even though these couplings are not visible on high speed (19)F 1D MAS spectra; in particular, we demonstrate that the J-resolved experiment combined with scalar multiple-quantum filtering considerably improves the resolution of J-multiplet patterns for dilute spin systems.
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Affiliation(s)
- Charlotte Martineau
- LdOF, CNRS UMR 6010, IRIM2F, CNRS FR 2575, Université du Maine, Avenue O. Messiaen, 72085 Le Mans Cedex 9, France.
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33
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Cadars S, Lesage A, Trierweiler M, Heux L, Emsley L. NMR measurements of scalar-coupling distributions in disordered solids. Phys Chem Chem Phys 2007; 9:92-103. [PMID: 17164890 DOI: 10.1039/b611096g] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The measurement of scalar (J) couplings by solid-state NMR is a field of great interest, since this interaction is a rich source of local structural information, complementary to dipolar and chemical shift interactions. Here, we first demonstrate that J-coupling distributions exist and can be observed in disordered solids, as illustrated with the observation of a pair-specific distribution of (2)J((31)P-N-(31)P) couplings in a bis-phosphino amine, and we investigate the potential effects of such distributions on the measurement of average J-coupling constants. Second, we show that the measurement of two-dimensional (2D) distributions of J-couplings provides a much richer probe of local structural disorder than one-dimensional distributions, and we introduce new methods that provide different (selective or non-selective) ways of measuring 2D J distributions in a wide range of disordered systems. These methods are finally applied to a slightly disordered polymorphic sample of fully (13)C-enriched cellulose, and then to the bis-phosphino amine sample, from which 2D (2)J(PP)-coupling distributions are clearly identified and interpreted.
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Affiliation(s)
- Sylvian Cadars
- Laboratoire de Chimie (UMR 5182 CNRS/ENS Lyon), Ecole Normale Supérieure de Lyon, Lyon, France
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34
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Affiliation(s)
- Cecil Dybowski
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716-2522, USA
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35
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Fayon F, Roiland C, Emsley L, Massiot D. Triple-quantum correlation NMR experiments in solids using J-couplings. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 179:49-57. [PMID: 16307897 DOI: 10.1016/j.jmr.2005.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 11/03/2005] [Accepted: 11/03/2005] [Indexed: 05/05/2023]
Abstract
We show that triple-quantum-single-quantum (TQ-SQ) correlation spectra of crystalline and disordered solids can be obtained under MAS using pulse sequences based on through-bond J-couplings. The feasibility of the experiments in coupled spin-1/2 systems is demonstrated for fully 13C-labelled L-alanine and Pb3P4O13 crystalline compounds, considered as model three-spin and four-spin systems, respectively. In the case of phosphate glasses, we show that the obtained TQ-SQ correlation spectra provide an improved description of the glass forming network connectivities and of the chain length distribution in the disordered network.
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Affiliation(s)
- Franck Fayon
- Centre de Recherches sur les Matériaux à Haute Température, CNRS, 45071 Orléans cedex 2, France.
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de Araujo CC, Strojek W, Zhang L, Eckert H, Poirier G, Ribeiro SJL, Messaddeq Y. Structural studies of NaPO3–WO3glasses by solid state NMR and Raman spectroscopy. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b605971f] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Flambard A, Montagne L, Delevoye L. A new 17O-isotopic enrichment method for the NMR characterisation of phosphate compounds. Chem Commun (Camb) 2006:3426-8. [PMID: 16896483 DOI: 10.1039/b604803j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Heating phosphate compounds under (17)O-enriched water vapour is an easy and rapid method to prepare homogeneously enriched and pure samples for the acquisition of (17)O NMR spectra with a good sensitivity.
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Affiliation(s)
- Alexandrine Flambard
- UCCS, Unité de Catalyse et Chimie du Solide, UMR-CNRS 8181, Ecole Nationale Supérieure de Chimie de Lille, Université des Sciences et Technologies de Lille, BP90108, 59655 Villeneuve d'Ascq, France
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