1
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Ko SL, Dorrell JA, Morris AJ, Griffith KJ. Metastable layered lithium-rich niobium and tantalum oxides via nearly instantaneous cation exchange. Faraday Discuss 2024. [PMID: 39301754 DOI: 10.1039/d4fd00103f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
Lithium-rich early transition metal oxides are the source of excess removeable lithium that affords high energy density to lithium-rich battery cathodes. They are also candidates for solid electrolytes in all-solid-state batteries. These highly ionic compounds are sparse on phase diagrams of thermodynamically stable oxides, but soft chemical routes offer an alternative to explore new alkali-rich crystal chemistries. In this work, a new layered polymorph of Li3NbO4 with coplanar [Nb4O16]12- clusters is discovered through ion exchange chemistry. A more detailed study of the ion exchange reaction reveals that it takes place almost instantaneously, changing the crystal volume by more than 22% within seconds. The transformation of coplanar [Nb4O16]12- in L-Li3NbO4 into the supertetrahedral [Nb4O16]12- clusters found in the stable cubic c-Li3NbO4 is also explored. Furthermore, this synthetic pathway is extended to access a new layered polymorph of Li3TaO4. NMR crystallography with 6,7Li, 23Na, and 93Nb NMR, X-ray diffraction, neutron diffraction, and first-principles calculations is applied to A3MO4 (A = Li, Na; M = Nb, Ta) to identify local and long-range atomic structure, to monitor the unusually rapid reaction progression, and to track the phase transitions from the metastable layered phases to the known compounds found using high-temperature synthesis. A mechanism is proposed whereby some sodium is retained at short reaction times, which then undergoes proton exchange during water washing, forming a phase with hydrogen bonds bridging the coplanar [Nb4O16]12- clusters. This study has implications for lithium-rich transition metal oxides and associated battery materials and for ion exchange chemistry in non-framework structures. The role of techniques that can detect light elements, local structure, and subtle structural changes in soft-chemical synthesis is emphasized.
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Affiliation(s)
- Sarah L Ko
- Department of Chemistry and Biochemistry, University of California, San Diego, California 92093, USA.
| | - Jordan A Dorrell
- School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Andrew J Morris
- School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Kent J Griffith
- Department of Chemistry and Biochemistry, University of California, San Diego, California 92093, USA.
- Program in Materials Science and Engineering, University of California, San Diego, California 92093, USA
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2
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González-Camuñas N, Cantín Á, Dawson DM, Lozinska MM, Martínez-Triguero J, Mattock J, Cox PA, Ashbrook SE, Wright PA, Rey F. Synthesis of the large pore aluminophosphate STA-1 and its application as a catalyst for the Beckmann rearrangement of cyclohexanone oxime. JOURNAL OF MATERIALS CHEMISTRY. A 2024; 12:15398-15411. [PMID: 38933527 PMCID: PMC11197783 DOI: 10.1039/d4ta01132e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 05/04/2024] [Indexed: 06/28/2024]
Abstract
The preparation of stable large pore aluminophosphate (AlPO) zeotypes offers materials for applications in adsorption and catalysis. Here we report the synthesis of the pure AlPO with the SAO topology type (AlPO STA-1) using N,N'-diethylbicyclo[2.2.2]oct-7-ene-2,3:5,6-dipyrrolidine (DEBOP) as the organic structure directing agent in the presence of fluoride. The AlPO STA-1 can be rendered microporous (pore volume 0.36 cm3 g-1) via calcination and the calcined form remains stable in the presence of moisture. The structure of the dehydrated form has been established by Rietveld refinement (tetragonal P4̄n2, a = 13.74317(10) Å, c = 21.8131(5) Å, V = 4119.94(16) Å3). Multinuclear 27Al and 31P MAS NMR, together with 2D COSY and CASTEP NMR calculations, enables resolution and assignment of the signals from all crystallographically distinct Al and P framework sites. Structural elucidation of the as-prepared aluminophosphate-fluoride is more challenging, because of the presence of partially protonated OSDA molecules in the 3D-connected channel system and in particular because the fluoride ions coordinate with positional disorder to some of the Al atoms to give 5-fold as well as tetrahedrally-coordinated framework Al species. These are postulated to occupy Al-F-Al bridging sites, where they are responsible for distortion of the framework [P4̄n2, a = 13.3148(9) Å, c = 22.0655(20) Å, V = 3911.9(7) Å3]. Calcination and removal of fluoride ions and OSDAs allows the framework to expand to its relaxed configuration. The SAO topology type aluminophosphate can also be synthesised with small amounts of Si and Ge in the framework, and these SAPO and GeAPO STA-1 materials are also stable to template removal. IR spectroscopy with CO as a probe at 123 K indicates all have weak-to-mild acidity, increasing in the order AlPO < GeAPO < SAPO. These STA-1 materials have been investigated for their activity in the Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam at 598 K: while all are active, the AlPO form is favoured due to its high selectivity and slow deactivation, both of which are a consequence of its very weak acid strength, which is nevertheless sufficient to catalyse the reaction.
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Affiliation(s)
- Nuria González-Camuñas
- Instituto de Tecnología Química (ITQ), Universitat Politècnica de València (UPV) - Consejo Superior de Investigaciones Científicas (CSIC) 46022 Valencia Spain
- Instituto de Tecnología Cerámica, Universidad Jaume I Campus Universitario Riu Sec, Avda. Vicente Sos Baynat s/n 12006 Castellón Spain
| | - Ángel Cantín
- Instituto de Tecnología Química (ITQ), Universitat Politècnica de València (UPV) - Consejo Superior de Investigaciones Científicas (CSIC) 46022 Valencia Spain
| | - Daniel M Dawson
- EaStCHEM School of Chemistry, University of St Andrews Purdie Building, St Andrews KY16 9ST UK
| | - Magdalena M Lozinska
- EaStCHEM School of Chemistry, University of St Andrews Purdie Building, St Andrews KY16 9ST UK
| | - Joaquín Martínez-Triguero
- Instituto de Tecnología Química (ITQ), Universitat Politècnica de València (UPV) - Consejo Superior de Investigaciones Científicas (CSIC) 46022 Valencia Spain
| | - James Mattock
- School of Pharmacy and Biomedical Sciences, University of Portsmouth Portsmouth PO1 2DT UK
| | - Paul A Cox
- School of Pharmacy and Biomedical Sciences, University of Portsmouth Portsmouth PO1 2DT UK
| | - Sharon E Ashbrook
- EaStCHEM School of Chemistry, University of St Andrews Purdie Building, St Andrews KY16 9ST UK
| | - Paul A Wright
- EaStCHEM School of Chemistry, University of St Andrews Purdie Building, St Andrews KY16 9ST UK
| | - Fernando Rey
- Instituto de Tecnología Química (ITQ), Universitat Politècnica de València (UPV) - Consejo Superior de Investigaciones Científicas (CSIC) 46022 Valencia Spain
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3
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Desai AV, Ettlinger R, Seleghini HS, Stanzione MG, Cabañero JM, Ashbrook SE, Morris RE, Armstrong AR. Rapid preparation of binary mixtures of sodium carboxylates as anodes in sodium-ion batteries. JOURNAL OF MATERIALS CHEMISTRY. A 2024; 12:12119-12125. [PMID: 38779224 PMCID: PMC11107158 DOI: 10.1039/d3ta06928a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 04/12/2024] [Indexed: 05/25/2024]
Abstract
Sodium-ion batteries are emerging as a sustainable solution to tackle the growing global energy demands. In this context, organic electrode materials complement such technologies as they are composed of earth-abundant elements. As organic anodes, sodium carboxylates exhibit promising applicability in a wide range of molecules. To harness the advantages of individual systems and to minimise their limitations, in this work, an approach to form binary mixtures of sodium carboxylates using one-pot, microwave-assisted synthesis is presented. The target mixtures were synthesised in 30 min with disodium naphthalene-2,6-dicarboxylate (Na-NDC) as a common constituent in all. Both components in all mixtures were shown to participate in the charge storage and had a considerable effect on the performance characteristics, such as specific capacity and working voltage, in half and full cell formats. This approach opens a new avenue for enabling organic materials to be considered as more competitive candidates in sodium-ion batteries and promote their use in other material classes to overcome their limitations.
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Affiliation(s)
- Aamod V Desai
- EaStCHEM School of Chemistry, University of St Andrews North Haugh St Andrews KY16 9ST UK
- The Faraday Institution, Quad One Harwell Science and Innovation Campus Didcot OX11 0RA UK
| | - Romy Ettlinger
- EaStCHEM School of Chemistry, University of St Andrews North Haugh St Andrews KY16 9ST UK
| | - Heitor S Seleghini
- EaStCHEM School of Chemistry, University of St Andrews North Haugh St Andrews KY16 9ST UK
| | | | - Joel M Cabañero
- EaStCHEM School of Chemistry, University of St Andrews North Haugh St Andrews KY16 9ST UK
- The Faraday Institution, Quad One Harwell Science and Innovation Campus Didcot OX11 0RA UK
| | - Sharon E Ashbrook
- EaStCHEM School of Chemistry, University of St Andrews North Haugh St Andrews KY16 9ST UK
| | - Russell E Morris
- EaStCHEM School of Chemistry, University of St Andrews North Haugh St Andrews KY16 9ST UK
- The Faraday Institution, Quad One Harwell Science and Innovation Campus Didcot OX11 0RA UK
| | - A Robert Armstrong
- EaStCHEM School of Chemistry, University of St Andrews North Haugh St Andrews KY16 9ST UK
- The Faraday Institution, Quad One Harwell Science and Innovation Campus Didcot OX11 0RA UK
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4
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Davis ZH, Borthwick EAL, Morris RE, Ashbrook SE. Computational NMR investigation of mixed-metal (Al,Sc)-MIL-53 and its phase transitions. Phys Chem Chem Phys 2023; 25:26486-26496. [PMID: 37767813 PMCID: PMC10566452 DOI: 10.1039/d3cp04147f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023]
Abstract
Compositionally complex metal-organic frameworks (MOFs) have properties that depend on local structure that is often difficult to characterise. In this paper a density functional theory (DFT) computational study of mixed-metal (Al,Sc)-MIL-53, a flexible MOF with several different forms, was used to calculate the relative energetics of these forms and to predict NMR parameters that can be used to evaluate whether solid-state NMR spectroscopy can be used to differentiate, identify and characterise the forms adopted by mixed-metal MOFs of different composition. The NMR parameters can also be correlated with structural features in the different forms, giving fundamental insight into the nature and origin of the interactions that affect nuclear spins. Given the complexity of advanced NMR experiments required, and the potential need for expensive and difficult isotopic enrichment, the computational work is invaluable in predicting which experiments and approaches are likely to give the most information on the disorder, local structure and pore forms of these mixed-metal MOFs.
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Affiliation(s)
- Zachary H Davis
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST, UK.
| | - Emma A L Borthwick
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST, UK.
| | - Russell E Morris
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST, UK.
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST, UK.
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5
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Berge AH, Pugh SM, Short MIM, Kaur C, Lu Z, Lee JH, Pickard CJ, Sayari A, Forse AC. Revealing carbon capture chemistry with 17-oxygen NMR spectroscopy. Nat Commun 2022; 13:7763. [PMID: 36522319 PMCID: PMC9755136 DOI: 10.1038/s41467-022-35254-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 11/21/2022] [Indexed: 12/23/2022] Open
Abstract
Carbon dioxide capture is essential to achieve net-zero emissions. A hurdle to the design of improved capture materials is the lack of adequate tools to characterise how CO2 adsorbs. Solid-state nuclear magnetic resonance (NMR) spectroscopy is a promising probe of CO2 capture, but it remains challenging to distinguish different adsorption products. Here we perform a comprehensive computational investigation of 22 amine-functionalised metal-organic frameworks and discover that 17O NMR is a powerful probe of CO2 capture chemistry that provides excellent differentiation of ammonium carbamate and carbamic acid species. The computational findings are supported by 17O NMR experiments on a series of CO2-loaded frameworks that clearly identify ammonium carbamate chain formation and provide evidence for a mixed carbamic acid - ammonium carbamate adsorption mode. We further find that carbamic acid formation is more prevalent in this materials class than previously believed. Finally, we show that our methods are readily applicable to other adsorbents, and find support for ammonium carbamate formation in amine-grafted silicas. Our work paves the way for investigations of carbon capture chemistry that can enable materials design.
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Affiliation(s)
- Astrid H Berge
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Suzi M Pugh
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Marion I M Short
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Chanjot Kaur
- Centre for Catalysis Research and Innovation (CCRI), Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Ziheng Lu
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Jung-Hoon Lee
- Computational Science Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Chris J Pickard
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
- Advanced Institute for Materials Research, Tohoku University, Aoba, Sendai, 980-8577, Japan
| | - Abdelhamid Sayari
- Centre for Catalysis Research and Innovation (CCRI), Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Alexander C Forse
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
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6
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Fernandes A, Moran RF, McKay D, Griffiths BL, Herlihy A, Whittle KR, Dawson DM, Ashbrook SE. Exploring cation disorder in mixed-metal pyrochlore ceramics using 17 O NMR spectroscopy and first-principles calculations. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:961-974. [PMID: 33565625 DOI: 10.1002/mrc.5140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Characterising the local structures (e.g., the cation distribution) of mixed-metal ceramics by NMR spectroscopy is often challenging owing to the unfavourable properties (low γ, large quadrupole moment and/or low abundance) of many metal nuclei. 17 O is an attractive option owing to the prevalence of oxygen within ceramics. The moderate γ and small quadrupole moment of 17 O mean that the greatest barrier to accessing the information available from this nucleus is isotopic enrichment. We explore the challenges of ensuring uniform isotopic enrichment with 17 O2 (g) for the pyrochlore solid solutions, Y2 Snx Ti2-x O7 , La2 Snx Zr2-x O7 and La2 Snx Hf2-x O7 , demonstrating that high enrichment temperatures (900 °C for 12 hr) are required. In addition, for sites with very high symmetry (such as the tetrahedral OY4 and OLa4 sites with CQ ≈ 0 present here), we demonstrate that quantitative 17 O NMR spectra require correction for the differing contributions from the centreband of the satellite transitions, which can be as high as a factor of ~3.89. It is common to use first-principles calculations to aid in interpreting NMR spectra of disordered solids. Here, we use an ensemble modelling approach to ensure that all possible cation arrangements are modelled in the minimum possible number of calculations. By combining uniform isotopic enrichment, quantitative NMR spectroscopy and a comprehensive computational approach, we are able to show that the cation distribution in Y2 Snx Ti2-x O7 is essentially random, whereas in La2 Snx Zr2-x O7 and La2 Snx Hf2-x O7 , OLa2SnZr and OLa2SnHf sites are slightly energetically disfavoured, leading to a weak preference for clustering of like cations.
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Affiliation(s)
- Arantxa Fernandes
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, UK
| | - Robert F Moran
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, UK
| | - David McKay
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, UK
| | - Ben L Griffiths
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, UK
| | - Anna Herlihy
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, UK
| | - Karl R Whittle
- School of Engineering, University of Liverpool, Liverpool, UK
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, UK
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, UK
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7
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Koppe J, Knitsch R, Wegner S, Hansen MR. Sensitivity-enhanced multiple-quantum MAS NMR for half-integer spin quadrupolar nuclei using WURST-amplitude shaped pulses. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 321:106873. [PMID: 33221668 DOI: 10.1016/j.jmr.2020.106873] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 06/11/2023]
Abstract
Two-dimensional multiple-quantum MAS (MQMAS) NMR spectroscopy is one of the most widely used solid-state NMR techniques for resolving multiple overlapping central-transition lineshapes for half-integer spin quadrupolar nuclei. In particular when relying on nutation-driven MQ coherence transfers, this technique suffers from low sensitivity that can only be improved by increasing the rf-amplitude of the involved radio-frequency (rf) pulses, which are therefore typically operated at the rf-limit. In such situations, frequently encountered for the three-pulse z-filtered and split-t1 shifted-echo MQMAS NMR sequences, we introduce the advantages of rf-pulses with smoothly truncated amplitude profiles, which we have termed WURST-Amplitude Shaped Pulses (WASPs). When considering the NMR spectrometer hardware, we demonstrate that WASPs feature more suitable properties in comparison to conventional rectangular pulses, enabling a substantial reduction of voltage reflections and transient effects under identical rf-conditions. By employing extensive numerical simulations and experimental validation, we further show that WASPs intrinsically possess a higher potential for nutation-based 3Q excitation involving spin-3/2 and 3Q and 5Q excitation for spin-5/2 quadrupolar nuclei, specifically when large nutation frequencies are available. The concept of smoothly truncating rf-amplitudes is also extended to Fast Amplitude Modulation (FAM) pulses, normally incorporated for rotor-driven 1Q conversion. We additionally evaluate the potential of employing WASPs with peak rf-amplitudes beyond the rf-limit for conventional rectangular rf-pulses.
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Affiliation(s)
- Jonas Koppe
- Institute for Physical Chemistry, Westfälische Wilhelms-Universität, Corrensstr. 28/30, D-48149 Münster, Germany
| | - Robert Knitsch
- Institute for Physical Chemistry, Westfälische Wilhelms-Universität, Corrensstr. 28/30, D-48149 Münster, Germany
| | | | - Michael Ryan Hansen
- Institute for Physical Chemistry, Westfälische Wilhelms-Universität, Corrensstr. 28/30, D-48149 Münster, Germany; Center for Multiscale Theory and Computation (CMTC), Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany.
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8
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Page SJ, Gallo A, Brown SP, Lewandowski JR, Hanna JV, Franks WT. Simultaneous MQMAS NMR Experiments for Two Half-Integer Quadrupolar Nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 320:106831. [PMID: 33022562 PMCID: PMC7661836 DOI: 10.1016/j.jmr.2020.106831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
A procedure to acquire two Multiple-Quantum Magic Angle Spinning (MQMAS) NMR experiments with the same instrument time is presented. A triply tuned probe is utilized with multiple receivers to collect data with staggered acquisitions and thus more efficiently use the instrument time. The data for one nucleus is collected during the recovery delay of the other nucleus, and vice versa. The instrument time is reduced to 60-80% of the time needed for the single acquisition collection Specifically our approach is presented for recording triple-quantum (3Q) 17O and either 3Q or quintuple-quantum (5Q) 27Al MAS NMR spectra of a 1.18Na2O•5SiO2•Al2O3 glass gel.
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Affiliation(s)
- Samuel J Page
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Angelo Gallo
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Steven P Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Józef R Lewandowski
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - John V Hanna
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - W Trent Franks
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom; Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
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9
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Rainer DN, Rice CM, Warrender SJ, Ashbrook SE, Morris RE. Mechanochemically assisted hydrolysis in the ADOR process. Chem Sci 2020; 11:7060-7069. [PMID: 33033606 PMCID: PMC7499815 DOI: 10.1039/d0sc02547j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/12/2020] [Indexed: 12/13/2022] Open
Abstract
The ADOR (Assembly-Disassembly-Organisation-Reassembly) process for zeolites has been shown to produce a number of previously unknown frameworks inaccessible through conventional synthesis methods. Here, we present successful mechanochemically assisted hydrolysis of germanosilicate zeolite UTL leading to ADOR products under mild conditions, low amounts of solvent and in short reaction times. The expansion of zeolite synthesis into the realm of mechanochemistry opens up feasible pathways regarding the production of these materials, especially for industrial purposes, as well as an exciting application for economical enrichment of materials with the low natural abundance NMR-active isotope of oxygen, 17O. The results from mechanochemically assisted hydrolysis differ from those seen in the traditional ADOR approach: differences that can be attributed to a change in solvent availability.
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Affiliation(s)
- Daniel N Rainer
- School of Chemistry , EaStCHEM , University of St. Andrews , North Haugh, St. Andrews , Fife , KY16 9ST , UK .
| | - Cameron M Rice
- School of Chemistry , EaStCHEM , University of St. Andrews , North Haugh, St. Andrews , Fife , KY16 9ST , UK .
| | - Stewart J Warrender
- School of Chemistry , EaStCHEM , University of St. Andrews , North Haugh, St. Andrews , Fife , KY16 9ST , UK .
| | - Sharon E Ashbrook
- School of Chemistry , EaStCHEM , University of St. Andrews , North Haugh, St. Andrews , Fife , KY16 9ST , UK .
| | - Russell E Morris
- School of Chemistry , EaStCHEM , University of St. Andrews , North Haugh, St. Andrews , Fife , KY16 9ST , UK .
- Department of Physical and Macromolecular Chemistry , Faculty of Sciences , Charles University , Hlavova 8 , 128 43 Prague 2 , Czech Republic
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10
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Cook DS, Hooper JE, Dawson DM, Fisher JM, Thompsett D, Ashbrook SE, Walton RI. Synthesis and Polymorphism of Mixed Aluminum-Gallium Oxides. Inorg Chem 2020; 59:3805-3816. [PMID: 32091886 PMCID: PMC7081611 DOI: 10.1021/acs.inorgchem.9b03459] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The synthesis of
a new solid solution of the oxyhydroxide Ga5–xAlxO7(OH) is investigated
via solvothermal reaction between gallium
acetylacetonate and aluminum isopropoxide in 1,4-butanediol at 240
°C. A limited compositional range of 0 ≤ x ≤ 1.5 is produced, with the hexagonal unit cell parameters
refined from powder X-ray diffraction (XRD) showing a linear contraction
in unit cell volume with an increase in Al content. Solid-state 27Al and 71Ga nuclear magnetic resonance (NMR) spectroscopies
show a strong preference for Ga to occupy the tetrahedral sites and
Al to occupy the octahedral sites. Using isopropanol as the solvent,
γ-Ga2–xAlxO3 defect spinel solid solutions with x ≤ 1.8 can be prepared at 240 °C in 24 h. These materials
are nanocrystalline, as evidenced by their broad diffraction profiles;
however, the refined cubic lattice parameter shows a linear relationship
with the Ga:Al content, and solid-state NMR spectroscopy again shows
a preference for Al to occupy the octahedral sites. Thermal decomposition
of Ga5–xAlxO7(OH) occurs via poorly ordered materials that
resemble ε-Ga2–xAlxO3 and κ-Ga2–xAlxO3, but
γ-Ga2–xAlxO3 transforms above 750 °C to monoclinic β-Ga2–xAlxO3 for 0 ≤ x ≤ 1.3 and to hexagonal
α-Ga2–xAlxO3 for x = 1.8, with intermediate
compositions of 1.3 < x < 1.8 giving mixtures
of the α- and β-polymorphs. Solid-state NMR spectroscopy
shows only the expected octahedral Al for α-Ga2–xAlxO3, and
for β-Ga2–xAlxO3, the ∼1:2 tetrahedral:octahedral
Al ratio is in good agreement with the results of Rietveld analysis
of the average structures against powder XRD data. Relative energies
calculated by periodic density functional theory confirm that there
is an ∼5.2 kJ mol–1 penalty for tetrahedral
rather than octahedral Al in Ga5–xAlxO7(OH), whereas this penalty
is much smaller (∼2.0 kJ mol–1) for β-Ga2–xAlxO3, in good qualitative agreement with the experimental NMR
spectra. Solvothermal reactions in 1,4-butanediol
or isopropanol
yield a new solid solution of the oxyhydroxide Ga5−xAlxO7(OH)
or the spinel series γ-Ga2−xAlxO3, respectively. We have
explored the possible composition range and the thermal stability
of the materials. For γ-Ga2−xAlxO3 (x ≤
1.3), transformation to the monoclinic β-polymorph occurs above
1000 °C, providing a convenient route to this material of interest
for electronic applications.
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Affiliation(s)
- Daniel S Cook
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Joseph E Hooper
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K
| | - Janet M Fisher
- Johnson Matthey Technology Centre, Sonning Common, Reading RG4 9NH, U.K
| | - David Thompsett
- Johnson Matthey Technology Centre, Sonning Common, Reading RG4 9NH, U.K
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K
| | - Richard I Walton
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
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11
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Pugh SM, Wright PA, Law DJ, Thompson N, Ashbrook SE. Facile, Room-Temperature 17O Enrichment of Zeolite Frameworks Revealed by Solid-State NMR Spectroscopy. J Am Chem Soc 2020; 142:900-906. [PMID: 31875398 DOI: 10.1021/jacs.9b10528] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new approach for room-temperature 17O enrichment of zeolites reveals a surprisingly dynamic and labile framework, where rapid and reversible bond breaking takes place. 17O NMR spectroscopy shows that although O sites in both framework Si-O-Al and Si-O-Si linkages are enriched simply on exposure to H217O(l), the enrichment of Si-O-Al species is more rapid, with a more uniform framework enrichment observed at longer durations. We demonstrate that this unexpected enrichment can be observed for two different framework topologies and for Na-exchanged (i.e., nonacidic) zeolites, as well as their protonic forms, confirming that the Brønsted acid proton is not necessary for isotopic exchange into the framework. This work not only offers new opportunities for structural characterization of these chemically and industrially important materials using NMR spectroscopy but suggests that further investigation of the rate and position of enrichment in zeolite frameworks could provide new insight into their chemical reactivity and their stability in aqueous-based applications such as ion exchange and catalysis.
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Affiliation(s)
- Suzi M Pugh
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St. Andrews , St. Andrews KY16 9ST , U.K
| | - Paul A Wright
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St. Andrews , St. Andrews KY16 9ST , U.K
| | - David J Law
- BP Chemicals Ltd., Research and Technology Centre , Saltend, Hull HU12 8DS , U.K
| | - Nicholas Thompson
- BP Chemicals Ltd., Research and Technology Centre , Saltend, Hull HU12 8DS , U.K
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St. Andrews , St. Andrews KY16 9ST , U.K
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12
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Rice CM, Davis ZH, McKay D, Bignami GPM, Chitac RG, Dawson DM, Morris RE, Ashbrook SE. Following the unusual breathing behaviour of 17O-enriched mixed-metal (Al,Ga)-MIL-53 using NMR crystallography. Phys Chem Chem Phys 2020; 22:14514-14526. [PMID: 32578644 DOI: 10.1039/d0cp02731f] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The breathing behaviour of 17O-enriched (Al,Ga)-MIL-53, a terephthalate-based metal-organic framework, has been investigated using a combination of solid-state nuclear magnetic resonance (NMR) spectroscopy, powder X-ray diffraction (PXRD) and first-principles calculations. These reveal that the behaviour observed for as-made, calcined, hydrated and subsequently dehydrated mixed-metal MIL-53 materials differs with composition, but cannot be described as the compositionally weighted average of the breathing behaviour seen for the two end members. Although the form of MIL-53 adopted by the as-made material is independent of metal composition, upon calcination, materials with higher levels of Al adopt an open pore (OP) form, as found for the Al end member, but substitution of Ga results in mixed pore materials, with OP and narrow pore (NP) forms co-existing. Although the Ga end member is prone to decomposition under the calcination conditions used, a low level of Al in the starting synthesis (5%) leads to an OP mixed-metal MOF that is stable to calcination. Upon hydration, all materials almost exclusively adopt a closed pore (CP) structure, with strong hydrogen bonding interactions with water leading to two distinct resonances from the carboxylate oxygens in 17O NMR spectra. When dehydrated, different framework structures are found for the two end members, OP for Al-MIL-53 and NP for Ga-MIL-53, with the proportion of NP MOF seen to increase systematically with the Ga content in mixed-metal materials, in contrast to the forms seen upon initial calcination. 17O NMR spectra of mixed-metal MIL-53 materials show an increased preference for clustering of like cations as the Ga content increases. This is not a result of the small-scale dry gel conversion reactions used for enrichment, as a similar cation distribution and clustering is also observed for (Al0.5,Ga0.5)-MIL-53 synthesised hydrothermally and enriched with 17O via post-synthetic steaming.
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Affiliation(s)
- Cameron M Rice
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews, KY16 9ST, UK.
| | - Zachary H Davis
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews, KY16 9ST, UK.
| | - David McKay
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews, KY16 9ST, UK.
| | - Giulia P M Bignami
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews, KY16 9ST, UK.
| | - Ruxandra G Chitac
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews, KY16 9ST, UK.
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews, KY16 9ST, UK.
| | - Russell E Morris
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews, KY16 9ST, UK. and Department of Physical and Macromolecular Chemistry, Faculty of Sciences, Charles University, Hlavova 8, 128 43 Prague 2, Czech Republic
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews, KY16 9ST, UK.
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13
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Seymour VR, Smith ME. Distinguishing between Structural Models of β'-Sialons Using a Combined Solid-State NMR, Powder XRD, and Computational Approach. J Phys Chem A 2019; 123:9729-9736. [PMID: 31642673 DOI: 10.1021/acs.jpca.9b06729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
β'-Sialons (Si6-zAlzOzN8-z, where 0 ≤ z ≤ ∼4.2) are studied using a combination of 29Si and 27Al solid-state NMR, using magnetic fields of up to 20 T, powder X-ray diffraction, and density functional theory (DFT) calculations of both the structure and NMR parameters. Four different structural models have been proposed in the literature for the replacement of silicon and nitrogen by aluminum and oxygen within a β-Si3N4-structured lattice. Experimental data are presented for the variation with composition (z) of the unit cell parameters from diffraction and the local coordination units present suggested by NMR data. The experimental data are compared to the changes with composition in the DFT calculations of the structure and the NMR parameters according to the four models, allowing the models to be distinguished. It is shown that only one of these, the domain model, is fully consistent with all of the experimental data and is, therefore, a good structural model for β'-sialons. More speculatively, it is suggested that for the domain model, 27Al NMR data might provide a constraint on the thickness of its aluminum-rich layers.
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Affiliation(s)
| | - M E Smith
- Vice-Chancellor's Office, University House , Lancaster University , Bailrigg , Lancaster LA1 4YW , U.K
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14
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Fast room temperature lability of aluminosilicate zeolites. Nat Commun 2019; 10:4690. [PMID: 31619677 PMCID: PMC6795794 DOI: 10.1038/s41467-019-12752-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/27/2019] [Indexed: 01/02/2023] Open
Abstract
Aluminosilicate zeolites are traditionally used in high-temperature applications at low water vapour pressures where the zeolite framework is generally considered to be stable and static. Increasingly, zeolites are being considered for applications under milder aqueous conditions. However, it has not yet been established how neutral liquid water at mild conditions affects the stability of the zeolite framework. Here, we show that covalent bonds in the zeolite chabazite (CHA) are labile when in contact with neutral liquid water, which leads to partial but fully reversible hydrolysis without framework degradation. We present ab initio calculations that predict novel, energetically viable reaction mechanisms by which Al-O and Si-O bonds rapidly and reversibly break at 300 K. By means of solid-state NMR, we confirm this prediction, demonstrating that isotopic substitution of 17O in the zeolitic framework occurs at room temperature in less than one hour of contact with enriched water. While aluminosilicate zeolites are of interest for many applications, the affect of water on zeolite stability in mild aqueous conditions has yet to be established. Here, using ab initio calculations and NMR spectroscopy, the authors show that covalent bonds in the zeolite chabazite are labile when in contact with neutral liquid water.
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15
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Kanwal N, Colaux H, Dawson DM, Nishiyama Y, Ashbrook SE. Sensitivity improvement in 5QMAS NMR experiments using FAM-N pulses. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 100:1-10. [PMID: 30903912 DOI: 10.1016/j.ssnmr.2019.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/11/2019] [Accepted: 03/11/2019] [Indexed: 06/09/2023]
Abstract
The multiple-quantum magic-angle spinning (MQMAS) experiment is a popular choice for obtaining high-resolution solid-state NMR spectra of quadrupolar nuclei with half-integer spin quantum number. However, its inherently poor sensitivity limits its application in more challenging systems. In particular, the use of higher-order multiple-quantum coherences, which have the potential to provide higher resolution in the isotropic spectrum, results in a further decrease in sensitivity. Here we extend our recent work, which introduced an automated, high-throughput approach to generate amplitude-modulated composite pulses (termed FAM-N) to improve the efficiency of the conversion of three-quantum coherences, and explore the use of similar pulses in five-quantum MAS experiments. We consider three different approaches, and are able to demonstrate that all three provide good enhancements over single pulse conversion in all but the most extreme cases, and work well at a range of spinning rates. We show that FAM-N pulses are robust to variation in the quadrupolar coupling and rf nutation rate, demonstrating their applicability in multisite systems and systems where direct experimental optimisation of complex composite pulses is not feasible. This work will ease the implementation of higher-order MQMAS experiments and enable their application to materials and systems that were previously deemed too difficult to study.
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Affiliation(s)
- Nasima Kanwal
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Henri Colaux
- RIKEN-JEOL Collaboration Center, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan; Center for Surface Chemistry and Catalysis, KU Leuven, 3001, Heverlee, Belgium
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo, 196-8558, Japan; NMR Science and Development Division, RIKEN SPring-8 Center, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST, UK.
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16
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Huhn K, Engelhorn T, Linker RA, Nagel AM. Potential of Sodium MRI as a Biomarker for Neurodegeneration and Neuroinflammation in Multiple Sclerosis. Front Neurol 2019; 10:84. [PMID: 30804885 PMCID: PMC6378293 DOI: 10.3389/fneur.2019.00084] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/22/2019] [Indexed: 01/18/2023] Open
Abstract
In multiple sclerosis (MS), experimental and ex vivo studies indicate that pathologic intra- and extracellular sodium accumulation may play a pivotal role in inflammatory as well as neurodegenerative processes. Yet, in vivo assessment of sodium in the microenvironment is hard to achieve. Here, sodium magnetic resonance imaging (23NaMRI) with its non-invasive properties offers a unique opportunity to further elucidate the effects of sodium disequilibrium in MS pathology in vivo in addition to regular proton based MRI. However, unfavorable physical properties and low in vivo concentrations of sodium ions resulting in low signal-to-noise-ratio (SNR) as well as low spatial resolution resulting in partial volume effects limited the application of 23NaMRI. With the recent advent of high-field MRI scanners and more sophisticated sodium MRI acquisition techniques enabling better resolution and higher SNR, 23NaMRI revived. These studies revealed pathologic total sodium concentrations in MS brains now even allowing for the (partial) differentiation of intra- and extracellular sodium accumulation. Within this review we (1) demonstrate the physical basis and imaging techniques of 23NaMRI and (2) analyze the present and future clinical application of 23NaMRI focusing on the field of MS thus highlighting its potential as biomarker for neuroinflammation and -degeneration.
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Affiliation(s)
- Konstantin Huhn
- Department of Neurology, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany
| | - Tobias Engelhorn
- Department of Neuroradiology, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany
| | - Ralf A Linker
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Armin M Nagel
- Department of Radiology, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany.,Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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17
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Fernandes A, Moran RF, Sneddon S, Dawson DM, McKay D, Bignami GPM, Blanc F, Whittle KR, Ashbrook SE. 17O solid-state NMR spectroscopy of A 2B 2O 7 oxides: quantitative isotopic enrichment and spectral acquisition? RSC Adv 2018; 8:7089-7101. [PMID: 29568509 PMCID: PMC5815285 DOI: 10.1039/c8ra00596f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 02/07/2018] [Indexed: 11/21/2022] Open
Abstract
The potential of 17O NMR spectroscopy for the investigation of A2B2O7 ceramic oxides important in the encapsulation of radioactive waste is demonstrated, with post-synthetic enrichment by exchange with 17O2 gas. For Y2Sn2O7, Y2Ti2O7 and La2Sn2O7 pyrochlores, enrichment of the two distinct O species is clearly non quantitative at lower temperatures (∼700 °C and below) and at shorter times, despite these being used in prior work, with preferential enrichment of OA2B2 favoured over that of OA4. At higher temperatures, the 17O NMR spectra suggest that quantitative enrichment has been achieved, but the integrated signal intensities do not reflect the crystallographic 1 : 6 (O1 : O2) ratio until corrected for differences in T1 relaxation rates and, more importantly, the contribution of the satellite transitions. 17O NMR spectra of Y2Zr2O7 and Y2Hf2O7 defect fluorites showed little difference with any variation in enrichment temperature or time, although an increase in the absolute level of enrichment (up to ∼7.5%) was observed at higher temperature. DFT calculations show that the six distinct resonances observed cannot be assigned unambiguously, as each has contributions from more than one of the five possible next nearest neighbour environments. For La2Ti2O7, which adopts a layered perovskite-like structure, little difference in the spectral intensities is observed with enrichment time or temperature, although the highest absolute levels of enrichment (∼13%) were obtained at higher temperature. This work demonstrates that 17O NMR has the potential to be a powerful probe of local structure and disorder in oxides, but that considerable care must be taken both in choosing the conditions for 17O enrichment and the experimental acquisition parameters if the necessary quantitative measurements are to be obtained for more complex systems.
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Affiliation(s)
- Arantxa Fernandes
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, UK.
| | - Robert F Moran
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, UK.
| | - Scott Sneddon
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, UK.
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, UK.
| | - David McKay
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, UK.
| | - Giulia P M Bignami
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, UK.
| | - Frédéric Blanc
- Department of Chemistry, Stephenson Institute for Renewable Energy, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
| | - Karl R Whittle
- School of Engineering, University of Liverpool, Brownlow Hill, Liverpool, L69 3GH, UK
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, UK.
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18
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Bignami GPM, Davis ZH, Dawson DM, Morris SA, Russell SE, McKay D, Parke RE, Iuga D, Morris RE, Ashbrook SE. Cost-effective 17O enrichment and NMR spectroscopy of mixed-metal terephthalate metal-organic frameworks. Chem Sci 2018; 9:850-859. [PMID: 29629152 PMCID: PMC5873045 DOI: 10.1039/c7sc04649a] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 11/23/2017] [Indexed: 11/21/2022] Open
Abstract
17O solid-state NMR spectroscopy is employed to investigate the cation disorder in metal-organic frameworks containing two different types of metal cations. Although NMR offers exquisite sensitivity to the local, atomic-scale structure, making it an ideal tool for the characterisation of disordered materials, the low natural abundance of 17O (0.037%) necessitates expensive isotopic enrichment to acquire spectra on a reasonable timescale. Using dry gel conversion and a novel steaming method we show that cost-effective and atom-efficient enrichment of MOFs is possible, and that high-resolution 17O NMR spectra are sensitive both to the structural forms of the MOF and the presence of guest molecules. For mixed-metal forms of MIL-53, NMR can also provide information on the final composition of the materials (notably different to that of the initial starting material) and the preference for cation clustering/ordering within the MOFs. For Al, Ga MIL-53, the distribution of cations results in a mixed-pore form upon exposure to water, unlike the different structures seen for the corresponding end members. This work shows that as good levels of enrichment can be achieved at reasonable cost, 17O NMR spectroscopy should be an invaluable tool for the study of these important functional materials.
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Affiliation(s)
- Giulia P M Bignami
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
| | - Zachary H Davis
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
| | - Daniel M Dawson
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
| | - Samuel A Morris
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
| | - Samantha E Russell
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
| | - David McKay
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
| | - Richard E Parke
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
| | - Dinu Iuga
- UK 850 MHz Solid-State NMR Facility , Department of Physics , University of Warwick , Millburn House , Coventry , CV4 7AL , UK
| | - Russell E Morris
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
| | - Sharon E Ashbrook
- School of Chemistry , EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , North Haugh, St Andrews , Fife , KY16 9ST , UK . ;
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19
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Duong NT, Nishiyama Y. Satellite and central transitions selective 1H/{ 27Al} D-HMQC experiments at very fast MAS for quadrupolar couplings determination. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 84:83-88. [PMID: 28089491 DOI: 10.1016/j.ssnmr.2016.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/20/2016] [Accepted: 12/29/2016] [Indexed: 06/06/2023]
Abstract
Recent study has demonstrated the application of the proton-detected heteronuclear multi-quantum coherence (HMQC) at ultrafast Magic Angle Spinning (MAS) to probe quadrupolar nuclei including 14N and 35Cl. In addition, for half-integer quadrupolar nucleus like 35Cl, the quadrupolar product can be calculated based on the shift difference between the center band of satellite transition (ST) and the central transition (CT) peaks. The applicability of this technique is further investigated on spin I=5/2, namely 27Al nucleus, and kaolin is chosen as the testing sample. However this study is not straightforward owing to a spin quantum number I=5/2 of 27Al nucleus and a small quadrupolar coupling of kaolin. Furthermore, very fast MAS, which is mandatory for proton-detected experiment to suppress 1H-1H homonuclear dipolar interactions, introduces additional complexities. It induces the partial overlap of CT and the center band of inner ST (ST1) resonance in addition to the insufficiency of CT-selective excitation by soft-pulse irradiation. In the current work, we employ the constant-time D-HMQC experiment, in which the duration between two recoupling blocks is fixed to a constant value and the arbitrary t1 increment can be used within this duration. This constant-time D-HMQC enables the precise determination of CT and ST resonance shifts through CT- and ST-selective observations by the indirect spectral width (i) with asynchronized sampling to the top of rotational-echoes for STs and (ii) three times larger than the spinning frequency, respectively. We also numerically and experimentally develop a satellite-selective excitation technique, in which the radio frequency field is applied to the first spinning sideband of ST1 resonance. The satellite-selective 1D single pulse and 2D conventional D-HMQC experiments are demonstrated. The quadrupolar product of 27Al nucleus extracted from the resulting spectra is in good agreement with the literature.
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Affiliation(s)
- Nghia Tuan Duong
- RIKEN CLST-JEOL collaboration center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Nishiyama
- RIKEN CLST-JEOL collaboration center, RIKEN, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
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20
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Colaux H, Dawson DM, Ashbrook SE. Investigating FAM-N pulses for signal enhancement in MQMAS NMR of quadrupolar nuclei. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 84:89-102. [PMID: 28131696 DOI: 10.1016/j.ssnmr.2017.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 06/06/2023]
Abstract
Although a popular choice for obtaining high-resolution solid-state NMR spectra of quadrupolar nuclei, the inherently low sensitivity of the multiple-quantum magic-angle spinning (MQMAS) experiment has limited its application for nuclei with low receptivity or when the available sample volume is limited. A number of methods have been introduced in the literature to attempt to address this problem. Recently, we have introduced an alternative, automated approach, based on numerical simulations, for generating amplitude-modulated pulses (termed FAM-N pulses) to enhance the efficiency of the triple- to single-quantum conversion step within MQMAS. This results in efficient pulses that can be used without experimental reoptimisation, ensuring that this method is particularly suitable for challenging nuclei and systems. In this work, we investigate the applicability of FAM-N pulses to a wider variety of systems, and their robustness under more challenging experimental conditions. These include experiments performed under fast MAS, nuclei with higher spin quantum numbers, samples with multiple distinct sites, low-γ nuclei and nuclei subject to large quadrupolar interactions.
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Affiliation(s)
- Henri Colaux
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
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21
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Kanehashi K. Structural roles of calcium in alkaline and alkaline-earth aluminosilicate glasses by solid-state 43Ca, 17O and 27Al NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 84:158-163. [PMID: 28283343 DOI: 10.1016/j.ssnmr.2017.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/30/2017] [Accepted: 03/02/2017] [Indexed: 06/06/2023]
Abstract
Structural roles of Ca in aluminosilicate glasses have been investigated by solid-state 43Ca, 17O, and 27Al NMR spectroscopy. In 15Al2O3-55SiO2-15CaO-15RO (R=Mg, Ca, Sr, and Na2) (mol%) glass systems wherein half of the alkaline plus alkaline-earth cations charge-compensate (AlO4)‒ tetrahedra and the other half modify the glass network, with decreasing cation field strength (CFS) in the order of Mg2+>Ca2+>Sr2+>Na+, the isotropic chemical shift (δiso) of 43Ca moves to a higher frequency and the quadrupolar coupling constant (PQ) of 43Ca decreases. The change in the δiso of 43Ca is more sensitive to the role of Ca than that in the PQ of 43Ca. The two possible roles (network modifier and charge compensator) of Ca in the glass with R=Ca are not distinguished in the 43Ca 3QMAS and 5QMAS spectra. The 17O 3QMAS results demonstrate that the cation with higher CFS (e.g., Mg2+ in the R=Mg glass and Ca2+ in the R=Na2 glass) dominantly creates non-bridging oxygen, even though there is slight cation mixing. With increasing CFS in the glass, the PQ of both 43Ca and 27Al also increases, indicating that the cation with higher CFS tends to degrade the structural symmetry.
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Affiliation(s)
- Koji Kanehashi
- Nippon Steel & Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu, Chiba 293-8511, Japan
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22
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Bignami GM, Dawson DM, Seymour VR, Wheatley PS, Morris RE, Ashbrook SE. Synthesis, Isotopic Enrichment, and Solid-State NMR Characterization of Zeolites Derived from the Assembly, Disassembly, Organization, Reassembly Process. J Am Chem Soc 2017; 139:5140-5148. [PMID: 28319391 PMCID: PMC5403117 DOI: 10.1021/jacs.7b00386] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Indexed: 11/28/2022]
Abstract
The great utility and importance of zeolites in fields as diverse as industrial catalysis and medicine has driven considerable interest in the ability to target new framework types with novel properties and applications. The recently introduced and unconventional assembly, disassembly, organization, reassembly (ADOR) method represents one exciting new approach to obtain solids with targeted structures by selectively disassembling preprepared hydrolytically unstable frameworks and then reassembling the resulting products to form materials with new topologies. However, the hydrolytic mechanisms underlying such a powerful synthetic method are not understood in detail, requiring further investigation of the kinetic behavior and the outcome of reactions under differing conditions. In this work, we report the optimized ADOR synthesis, and subsequent solid-state characterization, of 17O- and doubly 17O- and 29Si-enriched UTL-derived zeolites, by synthesis of 29Si-enriched starting Ge-UTL frameworks and incorporation of 17O from 17O-enriched water during hydrolysis. 17O and 29Si NMR experiments are able to demonstrate that the hydrolysis and rearrangement process occurs over a much longer time scale than seen by diffraction. The observation of unexpectedly high levels of 17O in the bulk zeolitic layers, rather than being confined only to the interlayer spacing, reveals a much more extensive hydrolytic rearrangement than previously thought. This work sheds new light on the role played by water in the ADOR process and provides insight into the detailed mechanism of the structural changes involved.
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Affiliation(s)
- Giulia
P. M. Bignami
- School of Chemistry, EaStCHEM
and Centre of Magnetic Resonance, University
of St. Andrews, North
Haugh, St. Andrews, Fife KY16 9ST, United Kingdom
| | - Daniel M. Dawson
- School of Chemistry, EaStCHEM
and Centre of Magnetic Resonance, University
of St. Andrews, North
Haugh, St. Andrews, Fife KY16 9ST, United Kingdom
| | - Valerie R. Seymour
- School of Chemistry, EaStCHEM
and Centre of Magnetic Resonance, University
of St. Andrews, North
Haugh, St. Andrews, Fife KY16 9ST, United Kingdom
| | - Paul S. Wheatley
- School of Chemistry, EaStCHEM
and Centre of Magnetic Resonance, University
of St. Andrews, North
Haugh, St. Andrews, Fife KY16 9ST, United Kingdom
| | - Russell E. Morris
- School of Chemistry, EaStCHEM
and Centre of Magnetic Resonance, University
of St. Andrews, North
Haugh, St. Andrews, Fife KY16 9ST, United Kingdom
| | - Sharon E. Ashbrook
- School of Chemistry, EaStCHEM
and Centre of Magnetic Resonance, University
of St. Andrews, North
Haugh, St. Andrews, Fife KY16 9ST, United Kingdom
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23
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Dawson DM, Walton RI, Wimperis S, Ashbrook SE. The ambient hydration of the aluminophosphate JDF-2 to AlPO-53(A): insights from NMR crystallography. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2017; 73:191-201. [PMID: 28257013 DOI: 10.1107/s2053229617000377] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/17/2017] [Indexed: 11/10/2022]
Abstract
The aluminophosphate (AlPO) JDF-2 is prepared hydrothermally with methylammonium hydroxide (MAH+·HO-, MAH+ = CH3NH3+), giving rise to a microporous AEN-type framework with occluded MAH+ cations and extra-framework (Al-bound) HO- anions. Despite the presence of these species within its pores, JDF-2 can hydrate upon exposure to atmospheric moisture to give AlPO-53(A), an isostructural material whose crystal structure contains one molecule of H2O per formula unit. This hydration can be reversed by mild heating (such as the frictional heating from magic angle spinning). Previous work has shown good agreement between the NMR parameters obtained experimentally and those calculated from the (optimized) crystal structure of JDF-2. However, several discrepancies are apparent between the experimental NMR parameters for AlPO-53(A) and those calculated from the (optimized) crystal structure (e.g. four 13C resonances are observed, rather than the expected two). The unexpected resonances appear and disappear reversibly with the respective addition and removal of H2O, so clearly arise from AlPO-53(A). We investigate the ambient hydration of JDF-2 using quantitative 31P MAS NMR to follow the transformation over the course of ∼3 months. The structures of JDF-2 and AlPO-53(A) are also investigated using a combination of multinuclear solid-state NMR spectroscopy to characterize the samples, and first-principles density functional theory (DFT) calculations to evaluate a range of possible structural models in terms of calculated NMR parameters and energetics. The published structure of JDF-2 is shown to be a good representation of the dehydrated material, but modification of the published structure of AlPO-53(A) is required to provide calculated NMR parameters that are in better agreement with experiment. This modification includes reorientation of all the MAH+ cations and partial occupancy of the H2O sites.
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Affiliation(s)
- Daniel M Dawson
- School of Chemistry, Centre for Magnetic Resonance and EaStCHEM, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, Scotland
| | - Richard I Walton
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, England
| | - Stephen Wimperis
- Department of Chemistry, Lancaster University, Lancaster LA1 4YB, England
| | - Sharon E Ashbrook
- School of Chemistry, Centre for Magnetic Resonance and EaStCHEM, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, Scotland
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24
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Seymour VR, Eschenroeder ECV, Wright PA, Ashbrook SE. An NMR crystallographic approach to monitoring cation substitution in the aluminophosphate STA-2. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 65:64-74. [PMID: 25465483 DOI: 10.1016/j.ssnmr.2014.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/18/2014] [Accepted: 10/23/2014] [Indexed: 06/04/2023]
Abstract
The substitution of the divalent cations Mg(2+) and Zn(2+) into the aluminophosphate (AlPO) framework of STA-2 has been studied using an "NMR crystallographic" approach, combining multinuclear solid-state NMR spectroscopy, X-ray diffraction and first-principles calculations. Although the AlPO framework itself is inherently neutral, the positive charge of the organocation template in an as-made material is usually balanced either by the coordination to the framework of anions from the synthesis solution, such as OH(-) or F(-), and/or by the substitution of aliovalent cations. However, the exact position and distribution of the substituted cations can be difficult to determine, but can have a significant impact upon the catalytic properties a material exhibits once calcined. For as-made Mg substituted STA-2, the positive charge of the organocation template is balanced by the substitution of Mg(2+) for Al(3+) and, where required, by hydroxide anions coordinated to the framework [27] Al MAS NMR spectra show that Al is present in both tetrahedral and five-fold coordination, with the latter dependent on the amount of substituted cations, and confirms the bridging nature of the hydroxyl groups, while high-resolution MQMAS spectra are able to show that Mg appears to preferentially substitute on the Al1 site. This conclusion is also supported by first-principles calculations. The calculations also show that (31)P chemical shifts depend not only on the topologically-distinct site in the SAT framework, but also on the number of next-nearest-neighbour Mg species, and the exact nature of the coordinated hydroxyls (whether the P atom forms part of a six-membered ring, P(OAl)2OH, where OH bridges between two Al atoms). The calculations demonstrate a strong correlation between the (31)P isotropic chemical shift and the average 〈P-O-M〉 bond angle. In contrast, for Zn substituted STA-2, both X-ray diffraction and NMR spectroscopy show less preference for substitution onto Al1 or Al2, with both appearing to be present, although that into Al1 appears slightly more favoured.
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Affiliation(s)
- Valerie R Seymour
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Eike C V Eschenroeder
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Paul A Wright
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
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25
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Bali S, Leisen J, Foo GS, Sievers C, Jones CW. Aminosilanes grafted to basic alumina as CO2 adsorbents--role of grafting conditions on CO2 adsorption properties. CHEMSUSCHEM 2014; 7:3145-3156. [PMID: 25179814 DOI: 10.1002/cssc.201402373] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/30/2014] [Indexed: 06/03/2023]
Abstract
Solid oxide-supported amine sorbents for CO2 capture are amongst the most rapidly developing classes of sorbent materials for CO2 capture. Herein, basic γ supports are used as hosts for amine sites through the grafting of 3-aminopropyltrimethoxysilane to the alumina surface under a variety of conditions, yielding the expected surface-grafted alkylamine groups, as demonstrated by FTIR spectroscopy and (29)Si and (13)C cross-polarization magic-angle spinning (CPMAS NMR) spectroscopy. Grafting amine sites on the surface in the presence of water leads to a high density of amine sites on the surface whereas simultaneously creating a unique type of aluminum species on the surface, as demonstrated by both 1D and 2D (27)Al MAS NMR spectroscopy. The thus prepared sorbents result in higher CO2 adsorption capacities and amine efficiencies compared to sorbents prepared in the absence of water or similar amine loading sorbents prepared using silica supports. In situ FTIR spectra of the sorbents exposed to CO2 at various pressures show no distinct difference in the nature of the adsorbed CO2 species on alumina- versus silica-supported amines, whereas water adsorption isotherms show that the improved performance of the amine-grafted alumina support is not a consequence of retained water on the more hydrophobic aminoalumina materials. The findings demonstrate that amine-grafted, basic alumina materials can be tuned to be more efficient than the corresponding silica-supported materials at comparable amine loadings, further demonstrating that the properties of amine sites can be tuned by controlling or adjusting the support surface properties.
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Affiliation(s)
- Sumit Bali
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, NW, Atlanta, GA, 30332 (USA)
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26
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Colaux H, Dawson DM, Ashbrook SE. Efficient amplitude-modulated pulses for triple- to single-quantum coherence conversion in MQMAS NMR. J Phys Chem A 2014; 118:6018-25. [PMID: 25047226 PMCID: PMC4126738 DOI: 10.1021/jp505752c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The conversion between multiple-
and single-quantum coherences
is integral to many nuclear magnetic resonance (NMR) experiments of
quadrupolar nuclei. This conversion is relatively inefficient when
effected by a single pulse, and many composite pulse schemes have
been developed to improve this efficiency. To provide the maximum
improvement, such schemes typically require time-consuming experimental
optimization. Here, we demonstrate an approach for generating amplitude-modulated
pulses to enhance the efficiency of the triple- to single-quantum
conversion. The optimization is performed using the SIMPSON and MATLAB
packages and results in efficient pulses that can be used without
experimental reoptimisation. Most significant signal enhancements
are obtained when good estimates of the inherent radio-frequency nutation
rate and the magnitude of the quadrupolar coupling are used as input
to the optimization, but the pulses appear robust to reasonable variations
in either parameter, producing significant enhancements compared to
a single-pulse conversion, and also comparable or improved efficiency
over other commonly used approaches. In all cases, the ease of implementation
of our method is advantageous, particularly for cases with low sensitivity,
where the improvement is most needed (e.g., low gyromagnetic ratio
or high quadrupolar coupling). Our approach offers the potential to
routinely improve the sensitivity of high-resolution NMR spectra of
nuclei and systems that would, perhaps, otherwise be deemed “too
challenging”.
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Affiliation(s)
- Henri Colaux
- School of Chemistry, EaStCHEM and Centre for Magnetic Resonance, University of St. Andrews , North Haugh, St. Andrews KY16 9ST, U.K
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27
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Sneddon S, Dawson DM, Pickard CJ, Ashbrook SE. Calculating NMR parameters in aluminophosphates: evaluation of dispersion correction schemes. Phys Chem Chem Phys 2014; 16:2660-73. [DOI: 10.1039/c3cp54123a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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28
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Peel MD, Ashbrook SE, Lightfoot P. Unusual Phase Behavior in the Piezoelectric Perovskite System, LixNa1–xNbO3. Inorg Chem 2013; 52:8872-80. [DOI: 10.1021/ic401061t] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martin D Peel
- School of Chemistry and EaStCHEM, University of St Andrews, St Andrews, KY16 9ST, UK
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29
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Bräuniger T, Jansen M. Solid-state NMR Spectroscopy of Quadrupolar Nuclei in Inorganic Chemistry. Z Anorg Allg Chem 2013. [DOI: 10.1002/zaac.201300102] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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30
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Seymour VR, Eschenroeder ECV, Castro M, Wright PA, Ashbrook SE. Application of NMR crystallography to the determination of the mechanism of charge-balancing in organocation-templated AlPO STA-2. CrystEngComm 2013. [DOI: 10.1039/c3ce40965a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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31
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Goswami M, Madhu PK. Combining dipolar-quadrupolar correlation spectroscopy with isotropic shift resolution in magic-angle-spinning 17O NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 219:4-12. [PMID: 22595292 DOI: 10.1016/j.jmr.2012.03.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Revised: 03/05/2012] [Accepted: 03/17/2012] [Indexed: 05/31/2023]
Abstract
We explore the effect of heteronuclear dipolar recoupling on the satellite and multiple-quantum transitions of a half-integer-spin quadrupolar nucleus coupled to a single spin-12. A three-dimensional experiment is introduced that resolves different quadrupolar sites whilst allowing simultaneous extraction of the quadrupolar coupling constants, asymmetry parameters of the electric field gradient, and the isotropic shifts of the quadrupolar nucleus. The experiment also enables estimation of the heteronuclear dipolar coupling constant between the spin-1/2 and half-integer spin quadrupolar nucleus. The relative orientation of the dipolar tensor with respect to the quadrupolar tensor can be estimated by comparing experiments and simulations. Experimental results are shown on a sample of brucite, Mg((17)OH)(2), where the (1)H-(17)O bond distance is estimated.
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Affiliation(s)
- M Goswami
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
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32
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Vitzthum V, Miéville P, Carnevale D, Caporini MA, Gajan D, Copéret C, Lelli M, Zagdoun A, Rossini AJ, Lesage A, Emsley L, Bodenhausen G. Dynamic nuclear polarization of quadrupolar nuclei using cross polarization from protons: surface-enhanced aluminium-27 NMR. Chem Commun (Camb) 2012; 48:1988-90. [PMID: 22237253 DOI: 10.1039/c2cc15905h] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The surface of γ-alumina nanoparticles can be characterized by dynamic nuclear polarization (DNP) surface-enhanced NMR of (27)Al. DNP is combined with cross-polarization and MQ-MAS to determine local symmetries of (27)Al sites at the surface.
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Affiliation(s)
- Veronika Vitzthum
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, EPFL, Batochime, 1015 Lausanne, Switzerland
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33
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Mowat JPS, Seymour VR, Griffin JM, Thompson SP, Slawin AMZ, Fairen-Jimenez D, Düren T, Ashbrook SE, Wright PA. A novel structural form of MIL-53 observed for the scandium analogue and its response to temperature variation and CO2adsorption. Dalton Trans 2012; 41:3937-41. [DOI: 10.1039/c1dt11729g] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Griffin JM, Clark L, Seymour VR, Aldous DW, Dawson DM, Iuga D, Morris RE, Ashbrook SE. Ionothermal 17O enrichment of oxides using microlitre quantities of labelled water. Chem Sci 2012. [DOI: 10.1039/c2sc20155k] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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35
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Johnston KE, Griffin JM, Walton RI, Dawson DM, Lightfoot P, Ashbrook SE. 93Nb NMR and DFT investigation of the polymorphs of NaNbO3. Phys Chem Chem Phys 2011; 13:7565-76. [DOI: 10.1039/c1cp20258h] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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36
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Hajjar R, Millot Y, Man PP. Phase cycling in MQMAS sequences for half-integer quadrupole spins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2010; 57:306-342. [PMID: 20667403 DOI: 10.1016/j.pnmrs.2010.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 05/11/2010] [Indexed: 05/29/2023]
Affiliation(s)
- Redouane Hajjar
- UPMC Univ Paris 06, FRE 3230, Laboratoire RMN des Matériaux Nanoporeux, 4 Place Jussieu, F-75005 Paris, France
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37
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Eckert H, Pöttgen R. 45Sc Solid State NMR Spectroscopy - A Complementary Tool to X-ray Crystallography for Structure Determination of Intermetallic Compounds. Z Anorg Allg Chem 2010. [DOI: 10.1002/zaac.201000197] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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38
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Carnevale D, del Amo V, Philp D, Ashbrook SE. Detecting solid-state reactivity in 10-hydroxy-10,9-boroxophenanthrene using NMR spectroscopy. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.05.065] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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39
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Chandran CV, Cuny J, Gautier R, Le Pollès L, Pickard CJ, Bräuniger T. Improving sensitivity and resolution of MQMAS spectra: a 45Sc-NMR case study of scandium sulphate pentahydrate. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 203:226-235. [PMID: 20089429 DOI: 10.1016/j.jmr.2009.12.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 12/18/2009] [Accepted: 12/24/2009] [Indexed: 05/28/2023]
Abstract
To efficiently obtain multiple-quantum magic-angle spinning (MQMAS) spectra of the nuclide 45Sc (I=7/2), we have combined several previously suggested techniques to enhance the signal-to-noise ratio and to improve spectral resolution for the test sample, scandium sulphate pentahydrate (ScSPH). Whereas the 45Sc-3QMAS spectrum of ScSPH does not offer sufficient resolution to clearly distinguish between the 3 scandium sites present in the crystal structure, these sites are well-resolved in the 5QMAS spectrum. The loss of sensitivity incurred by using MQMAS with 5Q coherence order is partly compensated for by using fast-amplitude modulated (FAM) sequences to improve the efficiency of both 5Q coherence excitation and conversion. Also, heteronuclear decoupling is employed to minimise dephasing of the 45Sc signal during the 5Q evolution period due to dipolar couplings with the water protons in the ScSPH sample. Application of multi-pulse decoupling schemes such as TPPM and SPINAL results in improved sensitivity and resolution in the F(1) (isotropic) dimension of the 5QMAS spectrum, the best results being achieved with the recently suggested SW(f)-TPPM sequence. By numerical fitting of the 45Sc-NMR spectra of ScSPH from 3QMAS, 5QMAS and single-quantum MAS at magnetic fields B(0)=9.4 T and 17.6 T, the isotropic chemical shift delta(iso), the quadrupolar coupling constant chi, and the asymmetry parameter eta were obtained. Averaging over all experiments, the NMR parameters determined for the 3 scandium sites, designated (a), (b) and (c) are: delta(iso)(a)=-15.5+/-0.5 ppm, chi(a)=5.60+/-0.10 MHz, eta(a)=0.06+/-0.05; delta(iso)(b)=-12.9+/-0.5 ppm, chi(b)=4.50+/-0.10 MHz, eta(b)=1.00+/-0.00; and delta(iso)(c)=-4.7+/-0.2 ppm, chi(c)=4.55+/-0.05 MHz, eta(c)=0.50+/-0.02. The NMR scandium species were assigned to the independent crystallographic sites by evaluating their experimental response to proton decoupling, and by density functional theory (DFT) calculations using the PAW and GIPAW approaches, in the following way: Sc(1) to (c), Sc(2) to (a), and Sc(3) to (b). The need to compute NMR parameters using an energy-optimised crystal structure is once again demonstrated.
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Affiliation(s)
- C Vinod Chandran
- Max-Planck-Institute of Solid-State Research, Heisenbergstr. 1, D-70569 Stuttgart, Germany
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40
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Gerothanassis IP. Oxygen-17 NMR spectroscopy: basic principles and applications (part I). PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2010; 56:95-197. [PMID: 20633350 DOI: 10.1016/j.pnmrs.2009.09.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 09/24/2009] [Indexed: 05/29/2023]
Affiliation(s)
- Ioannis P Gerothanassis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina GR-451 10, Greece.
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41
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Wang X, Smith LJ. Incomplete double frequency sweeps to select small quadrupolar coupling static powder patterns. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2009; 36:99-102. [PMID: 19660917 DOI: 10.1016/j.ssnmr.2009.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 01/14/2009] [Accepted: 06/16/2009] [Indexed: 05/28/2023]
Abstract
Difference spectra based on the magnitude of the quadrupolar coupling of a site has been observed under static conditions utilizing a double frequency sweep pulse sequence to enhance the central transition of a small electric field gradient (EFG) environment. Through the use of convergent sweeps that only cover the inner satellite transitions of the smaller EFG site, an echo spectrum results that favors the smaller site, which can then be used in conjunction with normal echo spectra to create a difference spectrum that consists primarily of the smaller site. The simplification of the static lineshape data permits simulation for the extraction of chemical shift anisotropy (CSA) information for the site. The method is demonstrated using (93)Nb NMR for samples with multiple niobium environments due to mixtures of compounds, MgNb(2)O(6)/LiNbO(3), or due to crystallographic structure, KCa(2)Nb(3)O(10).
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Affiliation(s)
- Xuefeng Wang
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, MA 01610, USA
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42
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Takahashi T, Kanehashi K, Shimoikeda Y, Nemoto T, Saito K. Practical comparison of sensitivity and resolution between STMAS and MQMAS for 27Al. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 198:228-235. [PMID: 19342257 DOI: 10.1016/j.jmr.2009.02.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 02/27/2009] [Accepted: 02/27/2009] [Indexed: 05/27/2023]
Abstract
An experimental comparison of sensitivity and resolution of satellite transition (ST) MAS and multiple quantum (MQ) MAS was performed for (27)Al (I=5/2) using several pulse sequences with a z-filter and SPAM, and two inorganic samples of kaolin (Al(2)Si(2)O(5)(OH)(4)) and glass (43.1CaO-12.5Al(2)O(3)-44.4SiO(2)). Six pulse sequences of STMAS (double-quantum filter-soft pulse added mixing=DQF-SPAM, double-quantum filter=DQF, double-quantum=DQ) and MQMAS (3QMAS-z-filter=3Qz, 3QMAS-SPAM=3Q-SPAM, 5QMAS-z-filter=5Qz) are employed. All experiments have been conducted utilizing a static field of 16.4T (700MHz for (1)H) and a rotor spinning frequency of 20kHz. Dependence of S/N ratios as a function of radio frequency (r.f.) field strengths indicates that strong r.f. fields are essential to obtain a better S/N ratio in all experiments. High sensitivity is obtained in the following order: DQF-SPAM, DQF, DQ, 3QSPAM, and 3Qz, although the degree of sensitivity enhancement given by STMAS for glass is slightly smaller than that for kaolin. This might be due to the different excitation and conversion efficiencies of ST and MQ coherences as a function C(q) values because quadrupolar interaction of the glass are widely distributed, or to motional broadening caused by framework flexibility in the structure of glass. With respect to resolution, the full widths at half maximum (FWHM) of F(1) projections of DQF-STMAS and 3QMAS spectra for kaolin are found to be comparable, which agrees with a simulated result reported in a literature. For glass, the STMAS possess slightly wider line widths than 3QMAS. However, because such a difference in line widths of STMAS and 3QMAS spectra is substantially small, we have concluded that STMAS and 3QMAS have comparable resolution for crystalline and non-crystalline materials.
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Affiliation(s)
- Takafumi Takahashi
- Advanced Technology Laboratories, Nippon Steel Corporation, 20-1 Shintomi, Futtsu, Chiba 293-8511, Japan.
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Hung I, Wong A, Howes AP, Anupõld T, Samoson A, Smith ME, Holland D, Brown SP, Dupree R. Separation of isotropic chemical and second-order quadrupolar shifts by multiple-quantum double rotation NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 197:229-236. [PMID: 19201231 DOI: 10.1016/j.jmr.2009.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 01/06/2009] [Accepted: 01/06/2009] [Indexed: 05/27/2023]
Abstract
Using a two-dimensional multiple-quantum (MQ) double rotation (DOR) experiment the contributions of the chemical shift and quadrupolar interaction to isotropic resonance shifts can be completely separated. Spectra were acquired using a three-pulse triple-quantum z-filtered pulse sequence and subsequently sheared along both the nu(1) and nu(2) dimensions. The application of this method is demonstrated for both crystalline (RbNO(3)) and amorphous samples (vitreous B(2)O(3)). The existence of the two rubidium isotopes ((85)Rb and (87)Rb) allows comparison of results for two nuclei with different spins (I=3/2 and 5/2), as well as different dipole and quadrupole moments in a single chemical compound. Being only limited by homogeneous line broadening and sample crystallinity, linewidths of approximately 0.1 and 0.2 ppm can be measured for (87)Rb in the quadrupolar and chemical shift dimensions, enabling highly accurate determination of the isotropic chemical shift and the quadrupolar product, P(Q). For vitreous B(2)O(3), the use of MQDOR allows the chemical shift and electric field gradient distributions to be directly determined-information that is difficult to obtain otherwise due to the presence of second-order quadrupolar broadening.
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Affiliation(s)
- Ivan Hung
- Physics Department, University of Warwick, Coventry, UK
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Ganapathy S, Delevoye L, Amoureux JP, Madhu PK. Heteronuclear dipolar decoupling effects on multiple-quantum and satellite-transition magic-angle spinning NMR spectra. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2008; 46:948-954. [PMID: 18720451 DOI: 10.1002/mrc.2286] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We here report on the influence of heteronuclear dipolar decoupling on the (27)Al 3QMAS, 5QMAS, and the double-quantum filter-satellite-transition magic-angle spinning (DQF-STMAS) spectra of a strongly dipolar-coupled system, gibbsite. The requirements for heteronuclear dipolar decoupling increase with the order of coherence evolving in the indirect dimension of a two-dimensional (2D) experiment. The isotropic line width of the high-resolution 2D spectra, in samples like gibbsite, is composed of four parts: the distribution of isotropic shifts (delta(ISO), delta(QIS)), the homogeneous broadening related to the proton-proton flip-flop terms, the (27)Al-(27)Al homonulcear dipolar couplings, and the (1)H-(27)Al heteronuclear dipolar couplings. It is shown that, even in the case of gibbsite, where a strong proton-proton bath exists, the main resolution limiting factor in these experiments resides in the (1)H-(27)Al dipolar interaction.
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Affiliation(s)
- S Ganapathy
- National Chemical Laboratory, Pune 411008, India
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Bräuniger T, Madhu PK. Fast amplitude-modulated pulse trains with frequency sweep (SW-FAM) in solid-state NMR of spin-7/2 nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 193:102-109. [PMID: 18462964 DOI: 10.1016/j.jmr.2008.04.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 04/14/2008] [Accepted: 04/15/2008] [Indexed: 05/26/2023]
Abstract
We here investigate the sensitivity enhancement of central-transition NMR spectra of quadrupolar nuclei with spin-7/2 in the solid state, generated by fast amplitude-modulated RF pulse trains with constant (FAM-I) and incremented pulse durations (SW-FAM). Considerable intensity is gained for the central-transition resonance of single-quantum spectra by means of spin population transfer from the satellite transitions, both under static and magic-angle-spinning (MAS) conditions. It is also shown that incorporation of a SW-FAM train into the excitation part of a 7QMAS sequence improves the efficiency of 7Q coherence generation, resulting in improved signal-to-noise ratio. The application of FAM-type pulse trains may thus facilitate faster spectra acquisition of spin-7/2 systems.
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Affiliation(s)
- Thomas Bräuniger
- Institute of Physics, University of Halle, Friedemann-Bach-Platz 6, DE-06108 Halle, Germany.
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Hajjar R, Millot Y, Man PP. NMR experimental procedure for obtaining 3Q and 5QMAS spectra from the same multiplex SPAM acquisition. CR CHIM 2008. [DOI: 10.1016/j.crci.2007.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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47
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Thrippleton MJ, Ball TJ, Wimperis S. Satellite transitions acquired in real time by magic angle spinning (STARTMAS): ‘‘Ultrafast’’ high-resolution MAS NMR spectroscopy of spin I=3∕2 nuclei. J Chem Phys 2008; 128:034507. [DOI: 10.1063/1.2813892] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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48
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Ashbrook SE, Cutajar M, Pickard CJ, Walton RI, Wimperis S. Structure and NMR assignment in calcined and as-synthesized forms of AlPO-14: a combined study by first-principles calculations and high-resolution 27Al–31P MAS NMR correlation. Phys Chem Chem Phys 2008; 10:5754-64. [DOI: 10.1039/b805681a] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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49
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Khabibulin D, Romanenko K, Zuev M, Lapina O. Solid state NMR characterization of individual compounds and solid solutions formed in Sc(2)O(3)--V(2)O(5)--Nb(2)O(5)--Ta(2)O(5) system. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2007; 45:962-970. [PMID: 17924354 DOI: 10.1002/mrc.2086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In this study, (51)V, (45)Sc and (93)Nb MAS NMR combined with satellite transition spectroscopy analysis were used to characterize the complex solid mixtures: VNb(9(1-x))Ta(9x)O(25), ScNb((1-x))Ta(x)O(4) and ScNb(2(1-x))Ta(2x)VO(9) (x = 0, 0.3, 0.5, 0.7, 1.0). This led us to describe the structures of Sc and V sites. The conclusions were based on accurate values for (51)V quadrupole coupling and chemical shift tensors obtained with (51)V MAS NMR/SATRAS for VNb(9)O(25), VTa(9)O(25) and ScVO(4). The (45)Sc NMR parameters have been obtained for Sc(2)O(3), ScVO(4), ScNbO(4) and ScTaO(4). On the basis of (45)Sc NMR and data available from literature, the ranges of the (45)Sc chemical shift have been established for ScO(6) and ScO(8). The gradual change of the (45)Sc and (51)V NMR parameters with x confirms the formation of solid solutions in the process of synthesis of VNb(9(1-x))Ta(9x)O(25) and ScNb((1-x))Ta(x)O(4), in contrast to ScNb(2(1-x))Ta(2x)VO(9). The cation sublattice of ScNb((1-x))Ta(x)O(4) is found to be in octahedral coordination. The V sites in VNb(9(1-x))Ta(9x)O(25) are present in the form of slightly distorted tetrahedra. The (93)Nb NMR parameters have been obtained for VNb(9)O(25).
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Affiliation(s)
- Dzhalil Khabibulin
- Boreskov Institute of Catalysis, SB RAS, Prosp. Lavrentieva 5, 630090 Novosibirsk, Russia
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50
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Ashbrook SE, Berry AJ, Frost DJ, Gregorovic A, Pickard CJ, Readman JE, Wimperis S. 17O and 29Si NMR Parameters of MgSiO3 Phases from High-Resolution Solid-State NMR Spectroscopy and First-Principles Calculations. J Am Chem Soc 2007; 129:13213-24. [DOI: 10.1021/ja074428a] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sharon E. Ashbrook
- Contribution from the School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K., Department of Earth Sciences and Engineering, Imperial College London, South Kensington SW7 2AZ, U.K., Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, U.K., School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, U.K., and Department of Chemistry
| | - Andrew J. Berry
- Contribution from the School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K., Department of Earth Sciences and Engineering, Imperial College London, South Kensington SW7 2AZ, U.K., Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, U.K., School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, U.K., and Department of Chemistry
| | - Daniel J. Frost
- Contribution from the School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K., Department of Earth Sciences and Engineering, Imperial College London, South Kensington SW7 2AZ, U.K., Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, U.K., School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, U.K., and Department of Chemistry
| | - Alan Gregorovic
- Contribution from the School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K., Department of Earth Sciences and Engineering, Imperial College London, South Kensington SW7 2AZ, U.K., Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, U.K., School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, U.K., and Department of Chemistry
| | - Chris J. Pickard
- Contribution from the School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K., Department of Earth Sciences and Engineering, Imperial College London, South Kensington SW7 2AZ, U.K., Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, U.K., School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, U.K., and Department of Chemistry
| | - Jennifer E. Readman
- Contribution from the School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K., Department of Earth Sciences and Engineering, Imperial College London, South Kensington SW7 2AZ, U.K., Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, U.K., School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, U.K., and Department of Chemistry
| | - Stephen Wimperis
- Contribution from the School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews KY16 9ST, U.K., Department of Earth Sciences and Engineering, Imperial College London, South Kensington SW7 2AZ, U.K., Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, U.K., School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, U.K., and Department of Chemistry
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