1
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Erastova V, Evans IR, Glossop WN, Guryel S, Hodgkinson P, Kerr HE, Oganesyan VS, Softley LK, Wickins HM, Wilson MR. Unravelling Guest Dynamics in Crystalline Molecular Organics Using 2H Solid-State NMR and Molecular Dynamics Simulation. J Am Chem Soc 2024; 146:18360-18369. [PMID: 38935813 PMCID: PMC11240262 DOI: 10.1021/jacs.4c03246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/30/2024] [Accepted: 05/30/2024] [Indexed: 06/29/2024]
Abstract
2H solid-state NMR and atomistic molecular dynamics (MD) simulations are used to understand the disorder of guest solvent molecules in two cocrystal solvates of the pharmaceutical furosemide. Traditional approaches to interpreting the NMR data fail to provide a coherent model of molecular behavior and indeed give misleading kinetic data. In contrast, the direct prediction of the NMR properties from MD simulation trajectories allows the NMR data to be correctly interpreted in terms of combined jump-type and libration-type motions. Time-independent component analysis of the MD trajectories provides additional insights, particularly for motions that are invisible to NMR. This allows a coherent picture of the dynamics of molecules restricted in molecular-sized cavities to be determined.
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Affiliation(s)
- Valentina Erastova
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
- Department
of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster
Road, Edinburgh EH9 3FJ, U.K.
| | - Ivana R. Evans
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
| | - William N. Glossop
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
| | - Songül Guryel
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
| | - Paul Hodgkinson
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
| | - Hannah E. Kerr
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
| | | | - Lorna K. Softley
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
| | - Helen M. Wickins
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
| | - Mark R. Wilson
- Department
of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, U.K.
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2
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Abotaleb A, Al-Masri D, Alkhateb A, Mroue K, Zekri A, Mashhour Y, Sinopoli A. Assessing the effect of acid and alkali treatment on a halloysite-based catalyst for dry reforming of methane. RSC Adv 2024; 14:4788-4803. [PMID: 38318606 PMCID: PMC10840390 DOI: 10.1039/d3ra07990b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/19/2024] [Indexed: 02/07/2024] Open
Abstract
Dry reforming of methane (DRM) has recently received wide attention owing to its outstanding performance in the reduction and conversion of CH4 and CO2 to syngas (H2 and CO). From an industrial perspective, nickel (Ni)-supported catalysts have been deemed among the most suitable catalysts for DRM owing to their low cost and high activity compared to noble metals. However, a downside of nickel catalysts is their high susceptibility to deactivation due to coke formation and sintering at high temperatures. Using appropriate supports and preparation methods plays a major role in improving the activity and stability of Ni-supported catalysts. Halloysite nanotubes (HNTs) are largely utilized in catalysis as a support for Ni owing to their abundance, low cost, and ease of preparation. The treatment of HNTs (chemical or physical) prior to doping with Ni is considered a suitable method for increasing the overall performance of the catalyst. In this study, the surface of HNTs was activated with acids (HNO3 and H2SO4) and alkalis (NaOH and Na2CO3 + NaNO3) prior to Ni doping to assess the effects of support treatment on the stability, activity, and longevity of the catalyst. Nickel catalysts on raw HNT, acid-treated HNT, and alkali-treated HNT supports were prepared via wet impregnation. A detailed characterization of the catalysts was conducted using X-ray diffraction (XRD), BET surface area analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), solid-state nuclear magnetic resonance (ssNMR), H2-temperature programmed reduction, (H2-TPR), CO2-temperature programmed desorption (CO2-TPD), and Ni-dispersion via H2-pulse chemisorption. Our results reveal a clear alteration in the structure of HNTs after treatment, while elemental mapping shows a uniform distribution of Ni throughout all the different supports. Moreover, the supports treated with a molten salt method resulted in the overall highest CO2 and CH4 conversion among the studied catalysts and exhibited high stability over 24 hours testing.
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Affiliation(s)
- Ahmed Abotaleb
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University P.O. Box 34110 Doha Qatar
| | - Dema Al-Masri
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University P.O. Box 34110 Doha Qatar
- Earthna Center for a Sustainable Future, Qatar Foundation Doha Qatar
| | - Alaa Alkhateb
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University P.O. Box 34110 Doha Qatar
| | - Kamal Mroue
- HBKU Core Labs, Hamad Bin Khalifa University P.O. Box 34110 Doha Qatar
| | - Atef Zekri
- HBKU Core Labs, Hamad Bin Khalifa University P.O. Box 34110 Doha Qatar
| | - Yasmin Mashhour
- Department of Chemistry and Earth Sciences, College of Arts and Sciences, Qatar University Doha P.O. Box 2713 Qatar
| | - Alessandro Sinopoli
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University P.O. Box 34110 Doha Qatar
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3
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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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4
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Zakary O, Body M, Charpentier T, Sarou-Kanian V, Legein C. Structural Modeling of O/F Correlated Disorder in TaOF 3 and NbOF 3-x(OH) x by Coupling Solid-State NMR and DFT Calculations. Inorg Chem 2023; 62:16627-16640. [PMID: 37747836 DOI: 10.1021/acs.inorgchem.3c02844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
The structure of MOF3 (M = Nb, Ta) compounds was precisely modeled by combining powder X-ray diffraction, solid-state NMR spectroscopy, and semiempirical dispersion-corrected DFT calculations. It consists of stacked ∞(MOF3) layers along the c⃗ direction formed by heteroleptic corner-connected MX6 (X = O, F) octahedra. 19F NMR resonance assignments and occupancy rates of the anionic crystallographic sites have been revised. The bridging site is shared equally by the anions, and the terminal site is occupied by F only. An O/F correlated disorder is expected since cis-MO2F4 octahedra are favored, resulting in one-dimensional -F-M-O-M- strings along the <100> and <010> directions. Ten different 2 × 2 × 1 supercells per compound, fulfilling these characteristics, were built. Using DFT calculations and the GIPAW approach, the supercells were relaxed and the 19F isotropic chemical shift values were determined. The agreement between the experimental and calculated 19F spectra is excellent for TaOF3. The 1H and 19F experimental NMR spectra revealed that some of the bridging F atoms are substituted by OH groups, especially in NbOF3. New supercells involving OH groups were generated. Remarkably, the best agreement is obtained for the supercells with the composition closest to that estimated from the 19F NMR spectra, i.e., NbOF2.85(OH)0.15.
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Affiliation(s)
- Ouail Zakary
- Institut des Molécules et Matériaux du Mans (IMMM) - UMR 6283 CNRSLe Mans Université, 72805 Le Mans Cedex 9, France
| | - Monique Body
- Institut des Molécules et Matériaux du Mans (IMMM) - UMR 6283 CNRSLe Mans Université, 72805 Le Mans Cedex 9, France
| | | | | | - Christophe Legein
- Institut des Molécules et Matériaux du Mans (IMMM) - UMR 6283 CNRSLe Mans Université, 72805 Le Mans Cedex 9, France
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5
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Fykouras K, Lahnsteiner J, Leupold N, Tinnemans P, Moos R, Panzer F, de Wijs GA, Bokdam M, Grüninger H, Kentgens APM. Disorder to order: how halide mixing in MAPbI 3-xBr x perovskites restricts MA dynamics. JOURNAL OF MATERIALS CHEMISTRY. A 2023; 11:4587-4597. [PMID: 37383090 PMCID: PMC10294545 DOI: 10.1039/d2ta09069d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 02/01/2023] [Indexed: 06/30/2023]
Abstract
Mixed-halide lead perovskites are of particular interest for the design of tandem solar cells currently reaching record efficiencies. While halide phase segregation upon illumination of mixed perovskites is extensively studied, the effect of halide disorder on A cation dynamics is not well understood, despite its importance for charge carrier diffusion and lifetime. Here, we study the methylammonium (MA) reorientational dynamics in mixed halide MAPbI3-xBrx perovskites by a combined approach of experimental solid-state NMR spectroscopy and molecular dynamics (MD) simulations based on machine-learning force-fields (MLFF). 207Pb NMR spectra indicate the halides are randomly distributed over their lattice positions, whereas PXRD measurements show that all mixed MAPbI3-xBrx samples are cubic. The experimental 14N spectra and 1H double-quantum (DQ) NMR data reveal anisotropic MA reorientations depending on the halide composition and thus associated disorder in the inorganic sublattice. MD calculations allow us to correlate these experimental results to restrictions of MA dynamics due to preferred MA orientations in their local Pb8I12-nBrn "cages". Based on the experimental and simulated results, we develop a phenomenological model that correlates the 1H dipolar coupling and thus the MA dynamics with the local composition and reproduces the experimental data over the whole composition range. We show that the dominant interaction between the MA cations and the Pb-X lattice that influences the cation dynamics is the local electrostatic potential being inhomogeneous in mixed halide systems. As such, we generate a fundamental understanding of the predominant interaction between the MA cations and the inorganic sublattice, as well as MA dynamics in asymmetric halide coordinations.
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Affiliation(s)
- Kostas Fykouras
- Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente P.O. Box 217 7500 AE Enschede Netherlands
| | - Jonathan Lahnsteiner
- Department of Functional Materials, University of Bayreuth Universitätsstraße 30 95447 Bayreuth Germany
| | - Nico Leupold
- Department of Functional Materials, University of Bayreuth Universitätsstraße 30 95447 Bayreuth Germany
| | - Paul Tinnemans
- Radboud University, Institute for Molecules and Materials Heyendaalseweg 135 6525 AJ Nijmegen Netherlands
| | - Ralf Moos
- Department of Functional Materials, University of Bayreuth Universitätsstraße 30 95447 Bayreuth Germany
| | - Fabian Panzer
- Soft Matter Optoelectronics, University of Bayreuth Universitätsstraße 30 95447 Bayreuth Germany
| | - Gilles A de Wijs
- Radboud University, Institute for Molecules and Materials Heyendaalseweg 135 6525 AJ Nijmegen Netherlands
| | - Menno Bokdam
- Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente P.O. Box 217 7500 AE Enschede Netherlands
| | - Helen Grüninger
- Radboud University, Institute for Molecules and Materials Heyendaalseweg 135 6525 AJ Nijmegen Netherlands
- Inorganic Chemistry III and Northern Bavarian NMR Centre, University of Bayreuth Universitätsstraße 30 95447 Bayreuth Germany
| | - Arno P M Kentgens
- Radboud University, Institute for Molecules and Materials Heyendaalseweg 135 6525 AJ Nijmegen Netherlands
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6
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Szell PMJ, Rehman Z, Tatman BP, Hughes LP, Blade H, Brown SP. Exploring the Potential of Multinuclear Solid-State 1 H, 13 C, and 35 Cl Magnetic Resonance To Characterize Static and Dynamic Disorder in Pharmaceutical Hydrochlorides. Chemphyschem 2023; 24:e202200558. [PMID: 36195553 PMCID: PMC10099218 DOI: 10.1002/cphc.202200558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/30/2022] [Indexed: 02/04/2023]
Abstract
Crystallographic disorder, whether static or dynamic, can be detrimental to the physical and chemical stability, ease of crystallization and dissolution rate of an active pharmaceutical ingredient. Disorder can result in a loss of manufacturing control leading to batch-to-batch variability and can lengthen the process of structural characterization. The range of NMR active nuclei makes solid-state NMR a unique technique for gaining nucleus-specific information about crystallographic disorder. Here, we explore the use of high-field 35 Cl solid-state NMR at 23.5 T to characterize both static and dynamic crystallographic disorder: specifically, dynamic disorder occurring in duloxetine hydrochloride (1), static disorder in promethazine hydrochloride (2), and trifluoperazine dihydrochloride (3). In all structures, the presence of crystallographic disorder was confirmed by 13 C cross-polarization magic-angle spinning (CPMAS) NMR and supported by GIPAW-DFT calculations, and in the case of 3, 1 H solid-state NMR provided additional confirmation. Applying 35 Cl solid-state NMR to these compounds, we show that higher magnetic fields are beneficial for resolving the crystallographic disorder in 1 and 3, while broad spectral features were observed in 2 even at higher fields. Combining the data obtained from 1 H, 13 C, and 35 Cl NMR, we show that 3 exhibits a unique case of disorder involving the + N-H hydrogen positions of the piperazinium ring, driving the chloride anions to occupy three distinct sites.
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Affiliation(s)
| | - Zainab Rehman
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Ben P Tatman
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Leslie P Hughes
- Oral Product Development Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield, SK10 2NA, UK
| | - Helen Blade
- Oral Product Development Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield, SK10 2NA, UK
| | - Steven P Brown
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
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7
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Scheidel S, Östreicher L, Mark I, Pöppler AC. You cannot fight the pressure: Structural rearrangements of active pharmaceutical ingredients under magic angle spinning. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:572-582. [PMID: 35277897 DOI: 10.1002/mrc.5267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
Although solid-state nuclear magnetic resonance (NMR) is a versatile analytical tool to study polymorphs and phase transitions of pharmaceutical molecules and products, this work summarizes examples of spontaneous and unexpected (and unwanted) structural rearrangements and phase transitions (amorphous-to-crystalline and crystalline-to-crystalline) under magic angle spinning (MAS) conditions, some of them clearly being due to the pressure experienced by the samples. It is widely known that such changes can often be detected by X-ray powder diffraction (XRPD); here, the capability of solid-state NMR experiments with a special focus on 1 H-13 C frequency-switched Lee-Goldburg heteronuclear correlation (FSLG HETCOR)/MAS NMR experiments to detect even subtle changes on a molecular level not observable by conventional 1D NMR experiments or XRPD is presented. Furthermore, it is shown that a polymorphic impurity combined with MAS can induce a crystalline-to-crystalline phase transition. This showcases that solid-state NMR is not always noninvasive and such changes upon MAS should be considered in particular when compounds are studied over longer time spans.
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Affiliation(s)
- Sebastian Scheidel
- Institute of Organic Chemistry, University of Würzburg, Würzburg, Germany
| | - Laurina Östreicher
- Institute of Organic Chemistry, University of Würzburg, Würzburg, Germany
| | - Isabelle Mark
- Institute of Organic Chemistry, University of Würzburg, Würzburg, Germany
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8
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Evans CL, Evans IR, Hodgkinson P. Resolving alternative structure determinations of indapamide using 13C solid-state NMR. Chem Commun (Camb) 2022; 58:4767-4770. [PMID: 35343549 DOI: 10.1039/d1cc06256e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The conflict between alternative crystal structures in the Cambridge Structural Database for the diuretic drug indapamide hemihydrate (IND) has been resolved with the aid of 13C solid-state NMR. IND is seen to contain multiple distinct molecules in the asymmetric unit (Z' = 4) rather than exhibiting disorder in the orientation of sulfonamide groups. The NMR crystallographic approach is a more effective tool for distinguishing between alternative structures than naïve judgements of quality based on crystallographic refinement agreement factors.
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Affiliation(s)
- Caitlin L Evans
- Department of Chemistry, Durham University, Stockton Road, Durham, DH1 3LE, UK.
| | | | - Paul Hodgkinson
- Department of Chemistry, Durham University, Stockton Road, Durham, DH1 3LE, UK.
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9
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Ke Z, Dawson DM, Ashbrook SE, Bühl M. Origin of the temperature dependence of 13C pNMR shifts for copper paddlewheel MOFs. Chem Sci 2022; 13:2674-2685. [PMID: 35340852 PMCID: PMC8890090 DOI: 10.1039/d1sc07138f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/02/2022] [Indexed: 11/21/2022] Open
Abstract
An efficient protocol for the calculation of 13C pNMR shifts in metal-organic frameworks based on Cu(ii) paddlewheel dimers is proposed, which involves simplified structural models, optimised using GFN2-xTB for the high-spin state, and CAM-B3LYP-computed NMR and EPR parameters. Models for hydrated and activated HKUST-1 and hydrated STAM MOFs with one, two and three Cu dimers have been used. The electronic ground states are low-spin and diamagnetic, with pNMR shifts arising from thermal population of intermediate- and high-spin excited states. Treating individual spin configurations in a broken symmetry (BS) approach, and selecting two or more of these to describe individual excited states, the magnetic shieldings of these paramagnetic states are evaluated using the approach by Hrobárik and Kaupp. The total shielding is then evaluated from a Boltzmann distribution between the energy levels of the chosen configurations. The computed pNMR shifts are very sensitive to temperature and, therefore, to the relative energies of the BS spin states. In order to reproduce the temperature dependence of the pNMR shifts seen in experiment, some scaling of the calculated energy gaps is required. A single scaling factor was applied to all levels in any one system, by fitting to experimental results at several temperatures simultaneously. The resulting scaling factor decreases with an increasing number of dimer units in the model (e.g., from ∼1.7 for mono-dimer models to 1.2 for tri-dimer models). The approach of this scaling factor towards unity indicates that models with three dimers are approaching a size where they can be considered as reasonable models for the 13C shifts of infinite MOFs. The observed unusual temperature dependencies in the latter are indicated to arise both from the "normal" temperature dependence of the pNMR shifts of the paramagnetic states and the populations of these states in the thermal equilibrium.
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Affiliation(s)
- Zhipeng Ke
- 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
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews St Andrews KY16 9ST UK
| | - Michael Bühl
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews St Andrews KY16 9ST UK
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10
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He C, Li S, Xiao Y, Xu J, Deng F. Application of solid-state NMR techniques for structural characterization of metal-organic frameworks. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 117:101772. [PMID: 35016011 DOI: 10.1016/j.ssnmr.2022.101772] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 12/27/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Solid-state NMR can afford the structural information about the chemical composition, local environment, and spatial coordination at the atomic level, which has been extensively applied to characterize the detailed structure and host-guest interactions in metal-organic frameworks (MOFs). In this review, recent advances for the structural characterizations of MOFs using versatile solid-state NMR techniques were briefly introduced. High-field sensitivity-enhanced solid-state NMR method enabled the direct observation of metal centers in MOFs containing low-γ nuclei. Two-dimensional (2D) homo- and hetero-nuclear correlation MAS NMR experiments provided the spatial proximity among linkers, metal clusters and the introduced guest molecules. Moreover, quantitative measurement of inter-nuclear distances using solid-state NMR provided valuable structural information about the connectivity geometry as well as the host-guest interactions within MOFs. Furthermore, solid-state NMR has exhibited great potential for unraveling the structure property of MOFs containing paramagnetic metal centers.
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Affiliation(s)
- Caiyan He
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Shenhui Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
| | - Yuqing Xiao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Jun Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Feng Deng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
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11
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Han X, Wu G, Du J, Pi J, Yan M, Hong X. Metal and metal oxide amorphous nanomaterials towards electrochemical applications. Chem Commun (Camb) 2021; 58:223-237. [PMID: 34878467 DOI: 10.1039/d1cc04141j] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amorphous nanomaterials have aroused extensive interest due to their unique properties. Their performance is highly related with their distinct atomic arrangements, which have no long-range order but possess short- to medium-range order. Herein, an overview of state-of-the-art synthesis methods of amorphous nanomaterials, structural characteristics and their electrochemical properties is presented. Advanced characterization methods for analyzing and proving the local order of amorphous structures, such as X-ray absorption fine structure spectroscopy, atomic electron tomography and nanobeam electron diffraction, are introduced. Various synthesis strategies for amorphous nanomaterials are covered, especially the salt-assisted metal organic decomposition method to prepare ultrathin amorphous nanosheets. Furthermore, the design and structure-activity relationship of amorphous nanomaterials towards electrochemical applications, including electrocatalysts and battery anode/cathode materials, is discussed.
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Affiliation(s)
- Xiao Han
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
| | - Geng Wu
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
| | - Junyi Du
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
| | - Jinglin Pi
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
| | - Muyu Yan
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
| | - Xun Hong
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
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12
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Szell PMJ, Nilsson Lill SO, Blade H, Brown SP, Hughes LP. A toolbox for improving the workflow of NMR crystallography. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2021; 116:101761. [PMID: 34736104 DOI: 10.1016/j.ssnmr.2021.101761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/04/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
NMR crystallography is a powerful tool with applications in structural characterization and crystal structure verification, to name two. However, applying this tool presents several challenges, especially for industrial users, in terms of consistency, workflow, time consumption, and the requirement for a high level of understanding of experimental solid-state NMR and GIPAW-DFT calculations. Here, we have developed a series of fully parameterized scripts for use in Materials Studio and TopSpin, based on the .magres file format, with a focus on organic molecules (e.g. pharmaceuticals), improving efficiency, robustness, and workflow. We separate these tools into three major categories: performing the DFT calculations, extracting & visualizing the results, and crystallographic modelling. These scripts will rapidly submit fully parameterized CASTEP jobs, extract data from the calculations, assist in visualizing the results, and expedite the process of structural modelling. Accompanied with these tools is a description on their functionality, documentation on how to get started and use the scripts, and links to video tutorials for guiding new users. Through the use of these tools, we hope to facilitate NMR crystallography and to harmonize the process across users.
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Affiliation(s)
| | - Sten O Nilsson Lill
- Early Product Development and Manufacturing, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - Helen Blade
- Oral Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield, UK
| | - Steven P Brown
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.
| | - Leslie P Hughes
- Oral Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield, UK.
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13
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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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14
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Ashbrook SE, Davis ZH, Morris RE, Rice CM. 17O NMR spectroscopy of crystalline microporous materials. Chem Sci 2021; 12:5016-5036. [PMID: 34163746 PMCID: PMC8179582 DOI: 10.1039/d1sc00552a] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 02/25/2021] [Indexed: 12/16/2022] Open
Abstract
Microporous materials, containing pores and channels of similar dimensions to small molecules have a range of applications in catalysis, gas storage and separation and in drug delivery. Their complex structure, often containing different types and levels of positional, compositional and temporal disorder, makes structural characterisation challenging, with information on both long-range order and the local environment required to understand the structure-property relationships and improve the future design of functional materials. In principle, 17O NMR spectroscopy should offer an ideal tool, with oxygen atoms lining the pores of many zeolites and phosphate frameworks, playing a vital role in host-guest chemistry and reactivity, and linking the organic and inorganic components of metal-organic frameworks (MOFs). However, routine study is challenging, primarily as a result of the low natural abundance of this isotope (0.037%), exacerbated by the presence of the quadrupolar interaction that broadens the spectral lines and hinders the extraction of information. In this Perspective, we will highlight the current state-of-the-art for 17O NMR of microporous materials, focusing in particular on cost-effective and atom-efficient approaches to enrichment, the use of enrichment to explore chemical reactivity, the challenge of spectral interpretation and the approaches used to help this and the information that can be obtained from NMR spectra. Finally, we will turn to the remaining challenges, including further improving sensitivity, the high-throughput generation of multiple structural models for computational study and the possibility of in situ and in operando measurements, and give a personal perspective on how these required improvements can be used to help solve important problems in microporous materials chemistry.
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Affiliation(s)
- Sharon E Ashbrook
- 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
| | - Russell E Morris
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews St Andrews KY16 9ST UK
| | - Cameron M Rice
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews St Andrews KY16 9ST UK
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15
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Grüninger H, Bokdam M, Leupold N, Tinnemans P, Moos R, De Wijs GA, Panzer F, Kentgens APM. Microscopic (Dis)order and Dynamics of Cations in Mixed FA/MA Lead Halide Perovskites. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:1742-1753. [PMID: 33542781 PMCID: PMC7848893 DOI: 10.1021/acs.jpcc.0c10042] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/31/2020] [Indexed: 05/02/2023]
Abstract
Recent developments in the field of high efficiency perovskite solar cells are based on stabilization of the perovskite crystal structure of FAPbI3 while preserving its excellent optoelectronic properties. Compositional engineering of, for example, MA or Br mixed into FAPbI3 results in the desired effects, but detailed knowledge of local structural features, such as local (dis)order or cation interactions of formamidinium (FA) and methylammonium (MA), is still limited. This knowledge is, however, crucial for their further development. Here, we shed light on the microscopic distribution of MA and FA in mixed perovskites MA1-x FA x PbI3 and MA0.15FA0.85PbI2.55Br0.45 by combining high-resolution double-quantum 1H solid-state nuclear magnetic resonance (NMR) spectroscopy with state-of-the-art near-first-principles accuracy molecular dynamics (MD) simulations using machine-learning force-fields (MLFFs). We show that on a small local scale, partial MA and FA clustering takes place over the whole MA/FA compositional range. A reasonable driving force for the clustering might be an increase of the dynamical freedom of FA cations in FA-rich regions. While MA0.15FA0.85PbI2.55Br0.45 displays similar MA and FA ordering as the MA1-x FA x PbI3 systems, the average cation-cation interaction strength increased significantly in this double mixed material, indicating a restriction of the space accessible to the cations or their partial immobilization upon Br- incorporation. Our results shed light on the heterogeneities in cation composition of mixed halide perovskites, helping to exploit their full optoelectronic potential.
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Affiliation(s)
- Helen Grüninger
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- H.G.: email,
| | - Menno Bokdam
- Faculty
of Physics and Center for Computational Materials Sciences, University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria
- Faculty
of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
- M.G.: email,
| | - Nico Leupold
- Department
of Functional Materials, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Paul Tinnemans
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Ralf Moos
- Department
of Functional Materials, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Gilles A. De Wijs
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Fabian Panzer
- Department
of Functional Materials, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
- Soft
Matter Optoelectronics, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Arno P. M. Kentgens
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- A.P.M.K.: email,
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16
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Reif B, Ashbrook SE, Emsley L, Hong M. Solid-state NMR spectroscopy. NATURE REVIEWS. METHODS PRIMERS 2021; 1:2. [PMID: 34368784 PMCID: PMC8341432 DOI: 10.1038/s43586-020-00002-1] [Citation(s) in RCA: 172] [Impact Index Per Article: 57.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/29/2020] [Indexed: 12/18/2022]
Abstract
Solid-state nuclear magnetic resonance (NMR) spectroscopy is an atomic-level method used to determine the chemical structure, three-dimensional structure, and dynamics of solids and semi-solids. This Primer summarizes the basic principles of NMR as applied to the wide range of solid systems. The fundamental nuclear spin interactions and the effects of magnetic fields and radiofrequency pulses on nuclear spins are the same as in liquid-state NMR. However, because of the anisotropy of the interactions in the solid state, the majority of high-resolution solid-state NMR spectra is measured under magic-angle spinning (MAS), which has profound effects on the types of radiofrequency pulse sequences required to extract structural and dynamical information. We describe the most common MAS NMR experiments and data analysis approaches for investigating biological macromolecules, organic materials, and inorganic solids. Continuing development of sensitivity-enhancement approaches, including 1H-detected fast MAS experiments, dynamic nuclear polarization, and experiments tailored to ultrahigh magnetic fields, is described. We highlight recent applications of solid-state NMR to biological and materials chemistry. The Primer ends with a discussion of current limitations of NMR to study solids, and points to future avenues of development to further enhance the capabilities of this sophisticated spectroscopy for new applications.
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Affiliation(s)
- Bernd Reif
- Technische Universität München, Department Chemie, Lichtenbergstr. 4, D-85747 Garching, Germany
| | - Sharon E. Ashbrook
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK
| | - Lyndon Emsley
- École Polytechnique Fédérale de Lausanne (EPFL), Institut des sciences et ingénierie chimiques, CH-1015 Lausanne, Switzerland
| | - Mei Hong
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
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17
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Szell PMJ, Brown SP, Hughes LP, Blade H, Nilsson Lill SO. A curious case of dynamic disorder in pyrrolidine rings elucidated by NMR crystallography. Chem Commun (Camb) 2020; 56:14039-14042. [PMID: 33103694 DOI: 10.1039/d0cc05236a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A pharmaceutical exhibits differing dynamics in crystallographically distinct pyrrolidine rings despite being nearly related by symmetry, with one performing ring inversions while the other is constrained to torsional librations. Using 13C solid-state magic-angle spinning (MAS) NMR and DFT calculations, we show that this contrast originates from C-HH-C close contacts and less efficient C-Hπ intermolecular interactions observed in the transition state of the constrained pyrrolidine ring, highlighting the influence of the crystallographic environment on the molecular motion.
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Affiliation(s)
- Patrick M J Szell
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.
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18
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A Practical Review of NMR Lineshapes for Spin-1/2 and Quadrupolar Nuclei in Disordered Materials. Int J Mol Sci 2020; 21:ijms21165666. [PMID: 32784642 PMCID: PMC7461203 DOI: 10.3390/ijms21165666] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/31/2020] [Accepted: 08/05/2020] [Indexed: 01/06/2023] Open
Abstract
NMR is a powerful spectroscopic method that can provide information on the structural disorder in solids, complementing scattering and diffraction techniques. The structural disorder in solids can generate a dispersion of local magnetic and electric fields, resulting in a distribution of isotropic chemical shift δiso and quadrupolar coupling CQ. For spin-1/2 nuclei, the NMR linewidth and shape under high-resolution magic-angle spinning (MAS) reflects the distributions of isotropic chemical shift, providing a rich source of disorder information. For quadrupolar nuclei, the second-order quadrupolar broadening remains present even under MAS. In addition to isotropic chemical shift, structural disorder can impact the electric field gradient (EFG) and consequently the quadrupolar NMR parameters. The distributions of quadrupolar coupling and isotropic chemical shift are superimposed with the second-order quadrupolar broadening, but can be potentially characterized by MQMAS (multiple-quantum magic-angle spinning) spectroscopy. We review analyses of NMR lineshapes in 2D DQ–SQ (double-quantum single-quantum) and MQMAS spectroscopies, to provide a guide for more general lineshape analysis. In addition, methods to enhance the spectral resolution and sensitivity for quadrupolar nuclei are discussed, including NMR pulse techniques and the application of high magnetic fields. The role of magnetic field strength and its impact on the strategy of determining optimum NMR methods for disorder characterization are also discussed.
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19
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Ashbrook SE, Dawson DM, Gan Z, Hooper JE, Hung I, Macfarlane LE, McKay D, McLeod LK, Walton RI. Application of NMR Crystallography to Highly Disordered Templated Materials: Extensive Local Structural Disorder in the Gallophosphate GaPO-34A. Inorg Chem 2020; 59:11616-11626. [PMID: 32799506 DOI: 10.1021/acs.inorgchem.0c01450] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present an NMR crystallographic investigation of two as-made forms of the recently characterized gallophosphate GaPO-34A, which has an unusual framework composition with a Ga:P ratio of 7:6 and contains both hydroxide and fluoride anions and either 1-methylimidazolium or pyridinium as the structure-directing agent. We combine previously reported X-ray crystallographic data with solid-state NMR spectroscopy and periodic density functional theory (DFT) calculations to show that the structure contains at least three distinct types of disorder (occupational, compositional, and dynamic). The occupational disorder arises from the presence of six anion sites per unit cell, but a total occupancy of five of these, leading to full occupancy of four sites and partial occupancy of the fifth and sixth (which are related by symmetry). The mixture of OH and F present leads to compositional disorder on the occupied anion sites, although the occupancy of some sites by F is calculated to be energetically unfavorable and signals relating to F on these sites are not observed by NMR spectroscopy, confirming that the compositional disorder is not random. Finally, a combination of high-field 71Ga NMR spectroscopy and variable-temperature 13C and 31P NMR experiments shows that the structure directing agents are dynamic on the microsecond time scale, which can be supported by averaging the 31P chemical shifts calculated with the SDA in different orientations. This demonstrates the value of an NMR crystallographic approach, particularly in the case of highly disordered crystalline materials, where the growth of large single crystals for conventional structure determination may not be possible owing to the extent of disorder present.
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Affiliation(s)
- 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
| | - 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
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Joseph E Hooper
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Laurie E Macfarlane
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - David McKay
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Lucy K McLeod
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Richard I Walton
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
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20
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Semykina DO, Yakovlev IV, Lapina OB, Kabanov AA, Kosova NV. Crystal structure and migration paths of alkaline ions in NaVPO 4F. Phys Chem Chem Phys 2020; 22:15876-15884. [PMID: 32638762 DOI: 10.1039/d0cp02204g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A sample with a nominal composition 'NaVPO4F' is prepared by mechanochemically assisted solid-state synthesis using quenching. A detailed study of its crystal and local structure is conducted by means of XRD and FTIR and solid-state 31P NMR spectroscopies in comparison with Na3V2(PO4)2F3. It is shown that the as-prepared 'NaVPO4F' has a multiphase composition, including NaVPO4F as the main phase and Na3V2(PO4)2F3 and Na2.57V4P4O17F as the side products. The crystal structure of NaVPO4F is described in the monoclinic C2/c space group. It is characterized by negligible V3+/V4+ oxidation with the corresponding F-/O2- substitution and the presence of structural disordering. Using the Voronoi-Dirichlet partition (VDP) method, the Na+ and Li+ migration pathways in Tavorite-like NaVPO4F and closely related LiVPO4F (with the triclinic structure, P1[combining macron] S.G.) are analyzed. While the Na+ migration is suppressed in both cases, the Na+/Li+ ion exchange in NaVPO4F with the formation of monoclinic LiVPO4F could occur, but is difficult due to the sodium immobility rather than the instability of the lithium derivatives as was concluded from the DFT calculations.
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Affiliation(s)
- D O Semykina
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze, 630128 Novosibirsk, Russia.
| | - I V Yakovlev
- Boreskov Institute of Catalysis SB RAS, 5 Pr. Lavrent'eva, 630090 Novosibirsk, Russia
| | - O B Lapina
- Boreskov Institute of Catalysis SB RAS, 5 Pr. Lavrent'eva, 630090 Novosibirsk, Russia
| | - A A Kabanov
- Samara State Technical University, SCTMS, 12 Novo-Sadovaya, 443110 Samara, Russia and P. N. Lebedev Physical Institute of the Russian Academy of Sciences, 221 Novo-Sadovaya, 443011 Samara, Russia
| | - N V Kosova
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze, 630128 Novosibirsk, Russia.
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21
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Alam TM, Allers JP, Jones BH. Heterogeneous Polymer Dynamics Explored Using Static 1H NMR Spectra. Int J Mol Sci 2020; 21:ijms21155176. [PMID: 32707773 PMCID: PMC7432559 DOI: 10.3390/ijms21155176] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/08/2020] [Accepted: 07/08/2020] [Indexed: 11/24/2022] Open
Abstract
NMR spectroscopy continues to provide important molecular level details of dynamics in different polymer materials, ranging from rubbers to highly crosslinked composites. It has been argued that thermoset polymers containing dynamic and chemical heterogeneities can be fully cured at temperatures well below the final glass transition temperature (Tg). In this paper, we described the use of static solid-state 1H NMR spectroscopy to measure the activation of different chain dynamics as a function of temperature. Near Tg, increasing polymer segmental chain fluctuations lead to dynamic averaging of the local homonuclear proton-proton (1H-1H) dipolar couplings, as reflected in the reduction of the NMR line shape second moment (M2) when motions are faster than the magnitude of the dipolar coupling. In general, for polymer systems, distributions in the dynamic correlation times are commonly expected. To help identify the limitations and pitfalls of M2 analyses, the impact of activation energy or, equivalently, correlation time distributions, on the analysis of 1H NMR M2 temperature variations is explored. It is shown by using normalized reference curves that the distributions in dynamic activation energies can be measured from the M2 temperature behavior. An example of the M2 analysis for a series of thermosetting polymers with systematically varied dynamic heterogeneity is presented and discussed.
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22
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Piveteau L, Aebli M, Yazdani N, Millen M, Korosec L, Krieg F, Benin BM, Morad V, Piveteau C, Shiroka T, Comas-Vives A, Copéret C, Lindenberg AM, Wood V, Verel R, Kovalenko MV. Bulk and Nanocrystalline Cesium Lead-Halide Perovskites as Seen by Halide Magnetic Resonance. ACS CENTRAL SCIENCE 2020; 6:1138-1149. [PMID: 32724848 PMCID: PMC7379391 DOI: 10.1021/acscentsci.0c00587] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Indexed: 05/17/2023]
Abstract
Lead-halide perovskites increasingly mesmerize researchers because they exhibit a high degree of structural defects and dynamics yet nonetheless offer an outstanding (opto)electronic performance on par with the best examples of structurally stable and defect-free semiconductors. This highly unusual feature necessitates the adoption of an experimental and theoretical mindset and the reexamination of techniques that may be uniquely suited to understand these materials. Surprisingly, the suite of methods for the structural characterization of these materials does not commonly include nuclear magnetic resonance (NMR) spectroscopy. The present study showcases both the utility and versatility of halide NMR and NQR (nuclear quadrupole resonance) for probing the structure and structural dynamics of CsPbX3 (X = Cl, Br, I), in both bulk and nanocrystalline forms. The strong quadrupole couplings, which originate from the interaction between the large quadrupole moments of, e.g., the 35Cl, 79Br, and 127I nuclei, and the local electric-field gradients, are highly sensitive to subtle structural variations, both static and dynamic. The quadrupole interaction can resolve structural changes with accuracies commensurate with synchrotron X-ray diffraction and scattering. It is shown that space-averaged site-disorder is greatly enhanced in the nanocrystals compared to the bulk, while the dynamics of nuclear spin relaxation indicates enhanced structural dynamics in the nanocrystals. The findings from NMR and NQR were corroborated by ab initio molecular dynamics, which point to the role of the surface in causing the radial strain distribution and disorder. These findings showcase a great synergy between solid-state NMR or NQR and molecular dynamics simulations in shedding light on the structure of soft lead-halide semiconductors.
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Affiliation(s)
- Laura Piveteau
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials
Science and Technology, Dübendorf, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - Marcel Aebli
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials
Science and Technology, Dübendorf, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - Nuri Yazdani
- Department
of Information Technology and Electrical Engineering, ETH Zürich, Zürich CH-8092, Switzerland
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Marthe Millen
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
| | - Lukas Korosec
- Department of Physics, ETH
Zürich, Otto Stern Weg 1, Zürich CH-8093, Switzerland
| | - Franziska Krieg
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials
Science and Technology, Dübendorf, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - Bogdan M. Benin
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials
Science and Technology, Dübendorf, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - Viktoriia Morad
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials
Science and Technology, Dübendorf, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - Christophe Piveteau
- Department of Physics, ETH
Zürich, Otto Stern Weg 1, Zürich CH-8093, Switzerland
| | - Toni Shiroka
- Department of Physics, ETH
Zürich, Otto Stern Weg 1, Zürich CH-8093, Switzerland
- Paul Scherrer
Institute, Villigen PSI CH-5232, Switzerland
| | - Aleix Comas-Vives
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
| | - Christophe Copéret
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
| | - Aaron M. Lindenberg
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
- Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Vanessa Wood
- Department
of Information Technology and Electrical Engineering, ETH Zürich, Zürich CH-8092, Switzerland
| | - René Verel
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
| | - Maksym V. Kovalenko
- Department of Chemistry
and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials
Science and Technology, Dübendorf, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
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23
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A brief introduction to the basics of NMR spectroscopy and selected examples of its applications to materials characterization. PHYSICAL SCIENCES REVIEWS 2020. [DOI: 10.1515/psr-2019-0086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AbstractNuclear magnetic resonance (NMR) spectroscopy is an analytical technique that gives information on the local magnetic field around atomic nuclei. Since the local magnetic field of the nucleus is directly influenced by such features of the molecular structure as constitution, configuration, conformation, intermolecular interactions, etc., NMR can provide exhaustive information on the chemical structure, which is unrivaled by any other analytical method. Starting from the 1950s, NMR spectroscopy first revolutionized organic chemistry and became an indispensable tool for the structure elucidation of small, soluble molecules. As the technique evolved, NMR rapidly conquered other disciplines of chemical sciences. When the analysis of macromolecules and solids also became feasible, the technique turned into a staple in materials characterization, too. All aspects of NMR spectroscopy, including technical and technological development, as well as its applications in natural sciences, have been growing exponentially since its birth. Hence, it would be impossible to cover, or even touch on, all topics of importance related to this versatile analytical tool. In this tutorial, we aim to introduce the reader to the basic principles of NMR spectroscopy, instrumentation, historical development and currently available brands, practical cost aspects, sample preparation, and spectrum interpretation. We show a number of advanced techniques relevant to materials characterization. Through a limited number of examples from different fields of materials science, we illustrate the immense scope of the technique in the analysis of materials. Beyond our inherently limited introduction, an ample list of references should help the reader to navigate further in the field of NMR spectroscopy.
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Krivdin LB. Recent advances in computational 31 P NMR: Part 1. Chemical shifts. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:478-499. [PMID: 31703153 DOI: 10.1002/mrc.4965] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/19/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
This is the first part of two closely related reviews dealing with the computation of phosphorus-31 nuclear magnetic resonance chemical shifts in a wide series of organophosphorus compounds including complexes, clusters, and bioorganic phosphorus compounds. In particular, the analysis of the accuracy factors, such as substitution effects, solvent effects, vibrational corrections, and relativistic effects, is presented. This review is dedicated to the Full Member of the Russian Academy of Sciences Professor Boris A. Trofimov in view of his invaluable contribution to the field of synthesis, nuclear magnetic resonance, and computation studies of organophosphorus compounds.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
- Angarsk State Technical University, Irkutsk Region, Russia
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Hodgkinson P. NMR crystallography of molecular organics. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 118-119:10-53. [PMID: 32883448 DOI: 10.1016/j.pnmrs.2020.03.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/25/2020] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
Developments of NMR methodology to characterise the structures of molecular organic structures are reviewed, concentrating on the previous decade of research in which density functional theory-based calculations of NMR parameters in periodic solids have become widespread. With a focus on demonstrating the new structural insights provided, it is shown how "NMR crystallography" has been used in a spectrum of applications from resolving ambiguities in diffraction-derived structures (such as hydrogen atom positioning) to deriving complete structures in the absence of diffraction data. As well as comprehensively reviewing applications, the different aspects of the experimental and computational techniques used in NMR crystallography are surveyed. NMR crystallography is seen to be a rapidly maturing subject area that is increasingly appreciated by the wider crystallographic community.
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Affiliation(s)
- Paul Hodgkinson
- Department of Chemistry, Durham University, Stockton Road, Durham DH1 3LE, UK.
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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
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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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Karasulu B, Emge SP, Groh MF, Grey CP, Morris AJ. Al/Ga-Doped Li 7La 3Zr 2O 12 Garnets as Li-Ion Solid-State Battery Electrolytes: Atomistic Insights into Local Coordination Environments and Their Influence on 17O, 27Al, and 71Ga NMR Spectra. J Am Chem Soc 2020; 142:3132-3148. [PMID: 31951131 PMCID: PMC7146863 DOI: 10.1021/jacs.9b12685] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
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Li7La3Zr2O12 (LLZO)
garnets are among the most promising solid electrolytes for next-generation
all-solid-state Li-ion battery applications due to their high stabilities
and ionic conductivities. To help determine the influence of different
supervalent dopants on the crystal structure and site preferences,
we combine solid-state 17O, 27Al, and 71Ga magic angle spinning (MAS) NMR spectroscopy and density-functional
theory (DFT) calculations. DFT-based defect configuration analysis
for the undoped and Al and/or Ga-doped LLZO variants uncovers an interplay
between the local network of atoms and the observed NMR signals. Specifically,
the two characteristic features observed in both 27Al and 71Ga NMR spectra result from both the deviations in the polyhedral
coordination/site-symmetry within the 4-fold coordinated Li1/24d sites
(rather than the doping of the other Li2/96h or La sites) and with
the number of occupied adjacent Li2 sites that share oxygen atoms
with these dopant sites. The sharp 27Al and 71Ga resonances arise from dopants located at a highly symmetric tetrahedral
24d site with four corner-sharing LiO4 neighbors, whereas
the broader features originate from highly distorted dopant sites
with fewer or no immediate LiO4 neighbors. A correlation
between the size of the 27Al/71Ga quadrupolar
coupling and the distortion of the doping sites (viz. XO4/XO5/XO6 with X = {Al/Ga}) is established. 17O MAS NMR spectra for these systems provide insights into
the oxygen connectivity network: 17O signals originating
from the dopant-coordinating oxygens are resolved and used for further
characterization of the microenvironments at the dopant and other
sites.
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Affiliation(s)
- Bora Karasulu
- Department of Physics, Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Steffen P Emge
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Matthias F Groh
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Clare P Grey
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Andrew J Morris
- School of Metallurgy and Materials , University of Birmingham , Birmingham B15 2TT , United Kingdom
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28
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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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29
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Grüne M, Luxenhofer R, Iuga D, Brown SP, Pöppler AC. 14N–1H HMQC solid-state NMR as a powerful tool to study amorphous formulations – an exemplary study of paclitaxel loaded polymer micelles. J Mater Chem B 2020; 8:6827-6836. [DOI: 10.1039/d0tb00614a] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
14N–1H HMQC experiments are powerful experiments to characterize amorphous drug–polymer formulations of paclitaxel yielding well-separated signals in the 14N dimension as well as information on the symmetry of 14N and 14N–1H interactions.
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Affiliation(s)
- Marvin Grüne
- Institute of Organic Chemistry
- University of Würzburg
- 97074 Würzburg
- Germany
| | - Robert Luxenhofer
- Lehrstuhl für Chemische Technologie der Materialsynthese
- University of Würzburg
- 97070 Würzburg
- Germany
| | - Dinu Iuga
- Department of Physics
- University of Warwick
- Coventry
- UK
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30
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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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31
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Moran RF, McKay D, Tornstrom PC, Aziz A, Fernandes A, Grau-Crespo R, Ashbrook SE. Ensemble-Based Modeling of the NMR Spectra of Solid Solutions: Cation Disorder in Y 2(Sn,Ti) 2O 7. J Am Chem Soc 2019; 141:17838-17846. [PMID: 31591883 PMCID: PMC6900218 DOI: 10.1021/jacs.9b09036] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
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The
sensitivity of NMR to the local environment, without the need for
any long-range order, makes it an ideal tool for the characterization
of disordered materials. Computational prediction of NMR parameters
can be of considerable help in the interpretation and assignment of
NMR spectra of solids, but the statistical representation of all possible
chemical environments for a solid solution is challenging. Here, we
illustrate the use of a symmetry-adapted configurational ensemble
in the simulation of NMR spectra, in combination with solid-state
NMR experiments. We show that for interpretation of the complex and
overlapped lineshapes that are typically observed, it is important
to go beyond a single-configuration representation or a simple enumeration
of local environments. The ensemble method leads to excellent agreement
between simulated and experimental spectra for Y2(Sn,Ti)2O7 pyrochlore ceramics, where the overlap of signals
from different local environments prevents a simple decomposition
of the experimental spectral lineshapes. The inclusion of a Boltzmann
weighting confirms that the best agreement with experiment is obtained
at higher temperatures, in the limit of full disorder. We also show
that to improve agreement with experiment, in particular at low dopant
concentrations, larger supercells are needed, which might require
alternative simulation approaches as the complexity of the system
increases. It is clear that ensemble-based modeling approaches in
conjunction with NMR spectroscopy offer great potential for understanding
configurational disorder, ultimately aiding the future design of functional
materials.
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Affiliation(s)
- Robert F Moran
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , St Andrews KY16 9ST , U.K
| | - David McKay
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , St Andrews KY16 9ST , U.K
| | | | - Alex Aziz
- Department of Chemistry , University of Reading , Whiteknights RG6 6AD , U.K
| | - Arantxa Fernandes
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , St Andrews KY16 9ST , U.K
| | - Ricardo Grau-Crespo
- Department of Chemistry , University of Reading , Whiteknights RG6 6AD , 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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32
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Inaguma Y, Ueda K, Katsumata T, Noda Y. Low-temperature formation of Pb2OF2 with O/F anion ordering by solid state reaction. J SOLID STATE CHEM 2019. [DOI: 10.1016/j.jssc.2019.06.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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33
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Dawson DM, Sansome CEF, McHugh LN, McPherson MJ, McCormick McPherson LJ, Morris RE, Ashbrook SE. 13C pNMR of "crumple zone" Cu(II) isophthalate metal-organic frameworks. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 101:44-50. [PMID: 31112890 DOI: 10.1016/j.ssnmr.2019.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/10/2019] [Accepted: 05/10/2019] [Indexed: 06/09/2023]
Abstract
NMR spectroscopy of paramagnetic materials (pNMR) has the potential to provide great structural insight, but many challenges remain in interpreting the spectra in detail. This work presents a study of a series of structurally analogous metal-organic frameworks (MOFs) based on 5-substituted isophthalate linkers and Cu(II) paddlewheel dimers, of interest owing to their "crumple zone" structural rearrangement on dehydration/rehydration. 13C MAS NMR spectra reveal a wide variation in the observed resonance position for chemically similar C species in the different MOFs but, despite this, resonances are overlapped in several cases. However, by considering a combination of the integration of quantitative spectra, the resonance position as a function of temperature and T1 relaxation measurements, the spectra can be fully assigned. It is also demonstrated that the prototypical MOF in this series, STAM-1, displays a crumple zone rearrangement on dehydration, similar to the well-characterised 5-ethoxyisophthalate MOF (STAM-17-OEt) although, while the materials have similar local C environments, dehydrated STAM-1 exhibits less long-range order.
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Affiliation(s)
- Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom.
| | - Charlotte E F Sansome
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Lauren N McHugh
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Matthew J McPherson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom; Energy Safety Research Institute, Swansea University, Fabian Way, Swansea, SA1 8EN, United Kingdom
| | - Laura J McCormick McPherson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Russell E Morris
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom.
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34
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Zhang F, Wang HW, Tominaga K, Hayashi M, Sasaki T. Terahertz Fingerprints of Short-Range Correlations of Disordered Atoms in Diflunisal. J Phys Chem A 2019; 123:4555-4564. [PMID: 31038953 DOI: 10.1021/acs.jpca.9b00580] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work proposes a terahertz (THz) spectroscopy approach to the investigation of one of the outstanding problems in crystallography-the structure analysis of a crystal with disorder. Form I of diflunisal, in which the two ortho sites on one phenyl ring of diflunisal show occupational disorder, was used for an illustration. THz radiation interacts with the collective vibrations of correlated disorder, thus providing a promising tool to examine the symmetry of short-range correlations of disordered atoms. Through a thorough examination of the selection rule of THz vibrations in which the disordered atoms are involved to different extents, we deduced that only four short-range correlation possibilities of disorder exist and all of them display unambiguous fingerprint peaks in the 50-170 cm-1 frequency region. We finally proposed an alternating packing model in which the correlation lengths of disorder are on the nanometer scale.
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Affiliation(s)
- Feng Zhang
- Molecular Photoscience Research Center , Kobe University , Nada, Kobe 657-0013 , Japan
| | - Houng-Wei Wang
- Center for Condensed Matter Sciences , National Taiwan University , 1 Roosevelt Rd., Sec. 4 , Taipei 10617 , Taiwan
| | - Keisuke Tominaga
- Molecular Photoscience Research Center , Kobe University , Nada, Kobe 657-0013 , Japan
| | - Michitoshi Hayashi
- Center for Condensed Matter Sciences , National Taiwan University , 1 Roosevelt Rd., Sec. 4 , Taipei 10617 , Taiwan
| | - Tetsuo Sasaki
- Research Institute of Electronics , Shizuoka University , Hamamatsu , Shizuoka 432-8011 , Japan
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35
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Dawson DM, Moran RF, Sneddon S, Ashbrook SE. Is the 31 P chemical shift anisotropy of aluminophosphates a useful parameter for NMR crystallography? MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:176-190. [PMID: 30105879 DOI: 10.1002/mrc.4788] [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: 05/10/2018] [Revised: 08/01/2018] [Accepted: 08/06/2018] [Indexed: 05/12/2023]
Abstract
The 31 P chemical shift anisotropy (CSA) offers a potential source of new information to help determine the structures of aluminophosphate (AlPO) framework materials. We investigate how to measure the CSAs, which are small (span of ~20-30 ppm) for AlPOs, demonstrating the need for CSA-amplification experiments (often in conjunction with 27 Al and/or 1 H decoupling) at high magnetic field (20.0 T) to obtain accurate values. We show that the most shielded component of the chemical shift tensor, δ33 , is related to the length of the shortest P─O bond, whereas the more deshielded components, δ11 and δ22 can be related more readily to the mean P─O bond lengths and P─O─Al angles. Using the case of Mg-doped STA-2 as an example, the CSA is shown to be much larger for P(OAl)4-n (OMg)n environments, primarily owing to a much shorter P─O(Mg) bond affecting δ33 , however, because the mean P─O bond lengths and P─O─T (T = Al, Mg) bond angles do not change significantly between P(OAl)4 and P(OAl)4-n (OMg)n sites, the isotropic chemical shifts for these species are similar, leading to overlapped spectral lines. When the CSA information is included, spectral assignment becomes unambiguous, therefore, although the specialist conditions required might preclude the routine measurement of 31 P CSAs in AlPOs, in some cases (particularly doped materials), the experiments can still provide valuable additional information for spectral assignment.
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Affiliation(s)
- Daniel M Dawson
- 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
| | - Scott Sneddon
- 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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36
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Lino JBDR, Ramalho TC. Exploring Through-Space Spin-Spin Couplings for Quantum Information Processing: Facing the Challenge of Coherence Time and Control Quantum States. J Phys Chem A 2019; 123:1372-1379. [PMID: 30673241 DOI: 10.1021/acs.jpca.8b09425] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nuclear magnetic resonance (NMR) is a powerful tool for studying quantum information processing (QIP). Recently quantum technologies have been proposed to overcome the challenges in large-scale NMR QIP. Furthermore, computational chemistry can promote its improvement. Nuclear spins-1/2 are natural qubits and have been used in most NMR quantum computation experiments. However, molecules that enable many qubits NMR QIP implementations should meet some requirements regarding their spectroscopic properties. Exceptionally large through-space (TS) P-P spin-spin coupling constants (SSCC or J) observed in 1,8-diphosphanaphthalenes (PPN) and in naphtho[1,8- cd]-1,2-dithiole phenylphosphines (NTP) were proposed and investigated to provide more accurate control within large-scale NMR QIP. Spectroscopic properties of PPN and NTP derivatives were explored by theoretical strategies using locally dense basis sets (LDBS). 31P chemical shifts (δ) calculated at the B3LYP/aug-cc-pVTZ-J level and TS P-P SSCCs at the PBE1PBE/pcJ-2 (LDBS-1) level are very close to the experimental data for the PPN molecule. Differently, for the NTP dimer, PBE1PBE/pcJ-2 (LDBS-2) predicts more accurate 31P δ, whereas PBE1PBE/Def2-TZVP (LDBS-1) forecasts more accurate TS P-P SSCCs. From our results, PPNo-F, PPNo-ethyl, and PPNo-NH2 were the best candidates for NMR QIP, in which the large TS SSCCS could face the need of long-time quantum gates implementations. Therefore, it could overcome natural limitations concerning the development of large-scale NMR.
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Affiliation(s)
| | - Teodorico Castro Ramalho
- Chemistry Department , Federal University of Lavras , 37200-000 Lavras , MG Brazil.,Center for Basic and Applied Research, Faculty of Informatics and Management , University Hradec Kralove , 50003 Hradec Kralove , Czech Republic
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37
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McKay D, Moran RF, Dawson DM, Griffin JM, Sturniolo S, Pickard CJ, Berry AJ, Ashbrook SE. A Picture of Disorder in Hydrous Wadsleyite-Under the Combined Microscope of Solid-State NMR Spectroscopy and Ab Initio Random Structure Searching. J Am Chem Soc 2019; 141:3024-3036. [PMID: 30676032 PMCID: PMC6385078 DOI: 10.1021/jacs.8b11519] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
![]()
The Earth’s
transition zone, at depths of 410–660
km, while being composed of nominally anhydrous magnesium silicate
minerals, may be subject to significant hydration. Little is known
about the mechanism of hydration, despite the vital role this plays
in the physical and chemical properties of the mantle, leading to
a need for improved structural characterization. Here we present an ab initio random structure searching (AIRSS) investigation
of semihydrous (1.65 wt % H2O) and fully hydrous (3.3 wt
% H2O) wadsleyite. Following the AIRSS process, k-means clustering was used to select sets of structures
with duplicates removed, which were then subjected to further geometry
optimization with tighter constraints prior to NMR calculations. Semihydrous
models identify a ground-state structure (Mg3 vacancies, O1–H
hydroxyls) that aligns with a number of previous experimental observations.
However, predicted NMR parameters fail to reproduce low-intensity
signals observed in solid-state NMR spectra. In contrast, the fully
hydrous models produced by AIRSS, which enable both isolated and clustered
defects, are able to explain observed NMR signals via just four low-enthalpy
structures: (i) a ground state, with isolated Mg3 vacancies and O1–H
hydroxyls; (ii/iii) edge-sharing Mg3 vacancies with O1–H and
O3–H species; and (iv) edge-sharing Mg1 and Mg3 vacancies with
O1–H, O3–H, and O4–H hydroxyls. Thus, the combination
of advanced structure searching approaches and solid-state NMR spectroscopy
is able to provide new and detailed insight into the structure of
this important mantle mineral.
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Affiliation(s)
- David McKay
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , St Andrews , KY16 9ST , U.K
| | - Robert F Moran
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , St Andrews , KY16 9ST , U.K
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance , University of St Andrews , St Andrews , KY16 9ST , U.K
| | - John M Griffin
- Department of Chemistry and Materials Science Institute , Lancaster University , Lancaster , LA1 4YB , U.K
| | - Simone Sturniolo
- Science and Technology Facilities Council , Rutherford Appleton Laboratory , Harwell Science and Innovation Campus, Didcot , Oxfordshire OX11 0QX , U.K
| | - Chris J Pickard
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge , CB3 0FS , U.K.,Advanced Institute for Materials Research , Tohoku University 2-1-1 Katahira , Aoba , Sendai 980-8577 , Japan
| | - Andrew J Berry
- Research School of Earth Sciences , Australian National University , Canberra , ACT 2601 , Australia
| | - 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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38
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Rimsza J, Sorte EG, Alam TM. Hydration and Hydroxylation of MgO in Solution: NMR Identification of Proton-Containing Intermediate Phases. ACS OMEGA 2019; 4:1033-1044. [PMID: 31459379 PMCID: PMC6648527 DOI: 10.1021/acsomega.8b02705] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/28/2018] [Indexed: 06/10/2023]
Abstract
Magnesium oxide (MgO)-engineered barriers used in subsurface applications will be exposed to high concentration brine environments and may form stable intermediate phases that can alter the effectiveness of the barrier. To explore the formation of these secondary intermediate phases, MgO was aged in water and three different brine solutions and characterized with X-ray diffraction (XRD) and 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. After aging, there is ∼4% molar equivalent of a hydrogen-containing species formed. The 1H MAS NMR spectra resolved multiple minor phases not visible in XRD, indicating that diverse disordered proton-containing environments are present in addition to crystalline Mg(OH)2 brucite. Density functional theory (DFT) simulations for the proposed Mg-O-H-, Mg-Cl-O-H-, and Na-O-H-containing phases were performed to index resonances observed in the experimental 1H MAS NMR spectra. Although the intermediate crystal structures exhibited overlapping 1H NMR resonances in the spectra, Mg-O-H intermediates were attributed to the growth of resonances in the δ +1.0 to 0.0 ppm region, and Mg-Cl-O-H structures produced the increasing contributions of the δ = +2.5 to 5.0 ppm resonances in the chloride-containing brines. Overall, 1H NMR analysis of aged MgO indicates the formation of a wide range of possible intermediate structures that cannot be observed or resolved in the XRD analysis.
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Affiliation(s)
- Jessica
M. Rimsza
- Department
of GeochemistryDepartment of Organic Materials Science, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Eric G. Sorte
- Department
of GeochemistryDepartment of Organic Materials Science, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Todd M. Alam
- Department
of GeochemistryDepartment of Organic Materials Science, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
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39
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Nanda R, Bowers GM, Loganathan N, Burton SD, Kirkpatrick RJ. Temperature dependent structure and dynamics in smectite interlayers: 23Na MAS NMR spectroscopy of Na-hectorite. RSC Adv 2019; 9:12755-12765. [PMID: 35515846 PMCID: PMC9063695 DOI: 10.1039/c9ra01056d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 04/11/2019] [Indexed: 11/25/2022] Open
Abstract
23Na MAS NMR spectroscopy of the smectite mineral hectorite acquired at temperatures from −120 °C to 40 °C in combination with the results from computational molecular dynamics (MD) simulations show the presence of complex dynamical processes in the interlayer galleries that depend significantly on their hydration state. The results indicate that site exchange occurs within individual interlayers that contain coexisting 1 and 2 water layer hydrates in different places. We suggest that the observed dynamical averaging may be due to motion of water volumes comparable to the dripplons recently proposed to occur in hydrated graphene interlayers (Yoshida et al. Nat. Commun., 2018, 9, 1496). Such motion would cause rippling of the T-O-T structure of the clay layers at frequencies greater than ∼25 kHz. For samples exposed to 0% relative humidity (R.H.), the 23Na spectra show the presence of two Na+ sites (probably 6 and 9 coordinated by basal oxygen atoms) that do not undergo dynamical averaging at any temperature from −120 °C to 40 °C. For samples exposed to R.H.s from 29% to 100% the spectra show the presence of three hydrated Na+ sites that undergo dynamical averaging beginning at −60 °C. These sites have different numbers of H2O molecules coordinating the Na+, and diffusion calculations indicate that they probably occur within the same individual interlayer. The average hydration state of Na+ increases with increasing R.H. and water content of the clay. 23Na MAS NMR spectroscopy of the smectite mineral hectorite acquired at temperature from −120 °C to 40 °C shows the presence of complex dynamical processes in the interlayer galleries that depend significantly on their hydration state.![]()
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Affiliation(s)
- Raju Nanda
- Department of Chemistry
- Michigan State University
- East Lansing
- USA
- Department of Chemistry
| | - Geoffrey M. Bowers
- Department of Chemistry and Biochemistry
- St. Mary's College of Maryland
- St. Mary's City
- USA
| | | | - Sarah D. Burton
- William R. Wiley Environmental and Molecular Sciences Laboratory
- Pacific Northwest National Laboratory
- Richland
- USA
| | - R. James Kirkpatrick
- Department of Chemistry
- Michigan State University
- East Lansing
- USA
- Department of Earth and Environmental Sciences
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40
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Ashbrook SE, Hodgkinson P. Perspective: Current advances in solid-state NMR spectroscopy. J Chem Phys 2018; 149:040901. [PMID: 30068173 DOI: 10.1063/1.5038547] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In contrast to the rapid and revolutionary impact of solution-state Nuclear Magnetic Resonance (NMR) on modern chemistry, the field of solid-state NMR has matured more slowly. This reflects the major technical challenges of much reduced spectral resolution and sensitivity in solid-state as compared to solution-state spectra, as well as the relative complexity of the solid state. In this perspective, we outline the technique developments that have pushed resolution to intrinsic limits and the approaches, including ongoing major developments in the field of Dynamic Nuclear Polarisation, that have enhanced spectral sensitivity. The information on local structure and dynamics that can be obtained using these gains in sensitivity and resolution is illustrated with a diverse range of examples from large biomolecules to energy materials and pharmaceuticals and from both ordered and highly disordered materials. We discuss how parallel developments in quantum chemical calculation, particularly density functional theory, have enabled experimental data to be translated directly into information on local structure and dynamics, giving rise to the developing field of "NMR crystallography."
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Affiliation(s)
- Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Paul Hodgkinson
- Department of Chemistry, Durham University, Durham DH1 4RD, United Kingdom
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41
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Camacho PS, Stanford MW, McKay D, Dawson DM, Athukorala Arachchige KS, Cordes DB, Slawin AMZ, Woollins JD, Ashbrook SE. Polymorphism, Weak Interactions and Phase Transitions in Chalcogen-Phosphorus Heterocycles. Chemistry 2018; 24:11067-11081. [PMID: 29791041 PMCID: PMC6099295 DOI: 10.1002/chem.201800978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Indexed: 01/03/2023]
Abstract
A series of P-E-containing heterocycles (E=chalcogen) with aromatic backbones were synthesised and characterised by single-crystal and powder XRD, microanalysis and mass spectrometry. Solution- and solid-state 31 P and 77 Se NMR spectroscopy revealed significant differences between the NMR parameters in solution and in the solid state, related to conformational changes in the molecules. Many compounds were shown to exhibit a number of different polymorphic structures (identified by single-crystal XRD), although the bulk material studied by solid-state NMR spectroscopy often contained just one major polymorph. For the unoxidised heterocycles, the presence of weak intermolecular J couplings was also investigated by DFT calculations.
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Affiliation(s)
- Paula Sanz Camacho
- School of Chemistry and EaStCHEM and Centre of Magnetic ResonanceUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | - Martin W. Stanford
- School of Chemistry and EaStCHEM and Centre of Magnetic ResonanceUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | - David McKay
- School of Chemistry and EaStCHEM and Centre of Magnetic ResonanceUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | - Daniel M. Dawson
- School of Chemistry and EaStCHEM and Centre of Magnetic ResonanceUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | | | - David B. Cordes
- School of Chemistry and EaStCHEM and Centre of Magnetic ResonanceUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | - Alexandra M. Z. Slawin
- School of Chemistry and EaStCHEM and Centre of Magnetic ResonanceUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | - J. Derek Woollins
- School of Chemistry and EaStCHEM and Centre of Magnetic ResonanceUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | - Sharon E. Ashbrook
- School of Chemistry and EaStCHEM and Centre of Magnetic ResonanceUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
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42
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Ashbrook SE, Griffin JM, Johnston KE. Recent Advances in Solid-State Nuclear Magnetic Resonance Spectroscopy. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2018; 11:485-508. [PMID: 29324182 DOI: 10.1146/annurev-anchem-061417-125852] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The sensitivity of nuclear magnetic resonance (NMR) spectroscopy to the local atomic-scale environment offers great potential for the characterization of a diverse range of solid materials. Despite offering more information than its solution-state counterpart, solid-state NMR has not yet achieved a similar level of recognition, owing to the anisotropic interactions that broaden the spectral lines and hinder the extraction of structural information. Here, we describe the methods available to improve the resolution of solid-state NMR spectra and the continuing research in this area. We also highlight areas of exciting new and future development, including recent interest in combining experiment with theoretical calculations, the rise of a range of polarization transfer techniques that provide significant sensitivity enhancements, and the progress of in situ measurements. We demonstrate the detailed information available when studying dynamic and disordered solids and discuss the future applications of solid-state NMR spectroscopy across the chemical sciences.
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Affiliation(s)
- Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St. Andrews, St. Andrews KY16 9ST, United Kingdom;
| | - John M Griffin
- Department of Chemistry and Materials Science Institute, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Karen E Johnston
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
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43
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Youngman R. NMR Spectroscopy in Glass Science: A Review of the Elements. MATERIALS 2018; 11:ma11040476. [PMID: 29565328 PMCID: PMC5951322 DOI: 10.3390/ma11040476] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 03/16/2018] [Accepted: 03/20/2018] [Indexed: 01/30/2023]
Abstract
The study of inorganic glass structure is critically important for basic glass science and especially the commercial development of glasses for a variety of technological uses. One of the best means by which to achieve this understanding is through application of solid-state nuclear magnetic resonance (NMR) spectroscopy, which has a long and interesting history. This technique is element specific, but highly complex, and thus, one of the many inquiries made by non-NMR specialists working in glass science is what type of information and which elements can be studied by this method. This review presents a summary of the different elements that are amenable to the study of glasses by NMR spectroscopy and provides examples of the type of atomic level structural information that can be achieved. It serves to inform the non-specialist working in glass science and technology about some of the benefits and challenges involved in the study of inorganic glass structure using modern, readily-available NMR methods.
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Affiliation(s)
- Randall Youngman
- Science & Technology Division, Corning Incorporated, SP-AR-02-4, Corning, NY 14831, USA.
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44
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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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45
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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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46
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Vowinkel S, Paul S, Gutmann T, Gallei M. Free-Standing and Self-Crosslinkable Hybrid Films by Core-Shell Particle Design and Processing. NANOMATERIALS (BASEL, SWITZERLAND) 2017; 7:E390. [PMID: 29140279 PMCID: PMC5707607 DOI: 10.3390/nano7110390] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 11/10/2017] [Accepted: 11/13/2017] [Indexed: 11/16/2022]
Abstract
The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a core-shell particle architecture. The synthesis of well-designed monodisperse core-shell particles by emulsion polymerization is the basic prerequisite for subsequent particle processing via the melt-shear organization technique. In more detail, the core particles consist of polystyrene (PS) or poly(methyl methacrylate) (PMMA), while the comparably soft particle shell consists of poly(ethyl acrylate) (PEA) and different alkoxysilane-based poly(methacrylate)s. For hybrid film formation and convenient self-cross-linking, different alkyl groups at the siloxane moieties were investigated in detail by solid-state Magic-Angle Spinning Nuclear Magnetic Resonance (MAS, NMR) spectroscopy revealing different crosslinking capabilities, which strongly influence the properties of the core or shell particle films with respect to transparency and iridescent reflection colors. Furthermore, solid-state NMR spectroscopy and investigation of the thermal properties by differential scanning calorimetry (DSC) measurements allow for insights into the cross-linking capabilities prior to and after synthesis, as well as after the thermally and pressure-induced processing steps. Subsequently, free-standing and self-crosslinked particle-based films featuring excellent particle order are obtained by application of the melt-shear organization technique, as shown by microscopy (TEM, SEM).
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Affiliation(s)
- Steffen Vowinkel
- Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany.
| | - Stephen Paul
- Eduard-Zintl Institute for Inorganic and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, D-64287 Darmstadt, Germany.
| | - Torsten Gutmann
- Eduard-Zintl Institute for Inorganic and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, D-64287 Darmstadt, Germany.
| | - Markus Gallei
- Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany.
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47
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Rankin AM, Webb PB, Dawson DM, Viger-Gravel J, Walder BJ, Emsley L, Ashbrook SE. Determining the Surface Structure of Silicated Alumina Catalysts via Isotopic Enrichment and Dynamic Nuclear Polarization Surface-Enhanced NMR Spectroscopy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:22977-22984. [PMID: 29234484 PMCID: PMC5722451 DOI: 10.1021/acs.jpcc.7b08137] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/25/2017] [Indexed: 05/05/2023]
Abstract
Isotopic enrichment of 29Si and DNP-enhanced NMR spectroscopy are combined to determine the detailed surface structure of a silicated alumina catalyst. The significant sensitivity enhancement provided by DNP is vital to the acquisition of multinuclear and multidimensional experiments that provide information on the atomic-level structure of the species present at the surface. Isotopic enrichment not only facilitates spectral acquisition, particularly given the low (1.5 wt %) Si loading, but also enables spectra with higher resolution than those acquired using DNP to be obtained. The unexpected similarity of conventional, CP, and DNP NMR spectra is attributed to the presence of adventitious surface water that forms a sufficiently dense 1H network at the silica surface so as to mediate efficient polarization transfer to all Si species regardless of their chemical nature. Spectra reveal the presence of Si-O-Si linkages at the surface (identified as Q4(3Al)-Q4(3Al)) and confirm that the anchoring of the surface overlayer with the alumina occurs through AlIV and AlV species only. This suggests the presence of Q3/Q4 Si at the surface affects the neighboring Al species, modifying the surface structure and making it less likely AlVI environments are in close spatial proximity. In contrast, Q1/Q2 species, bonded to the surface by fewer covalent bonds, have less of an effect on the surface, and more AlVI species are consequently found nearby. The combination of isotropic enrichment and DNP provides a definitive and fully quantitative description of the Si-modified alumina surface, and we demonstrate that almost one-third of the silicon at the surface is connected to another Si species, even at the low level of coverage used, lowering the propensity for the formation of Brønsted acid sites. This suggests that a variation in the synthetic procedure might be required to obtain a more even coverage for optimum performance. The work here will allow for more rigorous future investigations of structure-function relationships in these complex materials.
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Affiliation(s)
- Andrew
G. M. Rankin
- School
of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews KY16 9ST, United Kingdom
| | - Paul B. Webb
- School
of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews KY16 9ST, United Kingdom
- Sasol
UK Ltd., Purdie Building,
North Haugh, St. Andrews KY16 9ST, United Kingdom
| | - Daniel M. Dawson
- School
of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews KY16 9ST, United Kingdom
| | - Jasmine Viger-Gravel
- Institut
des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Brennan J. Walder
- Institut
des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Lyndon Emsley
- Institut
des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Sharon E. Ashbrook
- School
of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St. Andrews KY16 9ST, United Kingdom
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48
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Sneddon S, Kahr J, Orsi AF, Price DJ, Dawson DM, Wright PA, Ashbrook SE. Investigation of zeolitic imidazolate frameworks using 13C and 15N solid-state NMR spectroscopy. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 87:54-64. [PMID: 28942230 DOI: 10.1016/j.ssnmr.2017.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal-organic frameworks (MOFs) with extended three-dimensional networks of transition metal nodes (bridged by rigid imidazolate linkers), with potential applications in gas storage and separation, sensing and controlled delivery of drug molecules. Here, we investigate the use of 13C and 15N solid-state NMR spectroscopy to characterise the local structure and disorder in a variety of single- and dual-linker ZIFs. In most cases, a combination of a basic knowledge of chemical shifts typically observed in solution-state NMR spectroscopy and the use of dipolar dephasing NMR experiments to reveal information about quaternary carbon species are combined to enable spectral assignment. Accurate measurement of the anisotropic components of the chemical shift provided additional information to characterise the local environment and the possibility of trying to understand the relationships between NMR parameters and both local and long-range structure. First-principles calculations on some of the simpler, ordered ZIFs were possible, and provided support for the spectral assignments, while comparison of these model systems to more disordered ZIFs aided interpretation of the more complex spectra obtained. It is shown that 13C and 15N NMR are sufficiently sensitive to detect small changes in the local environment, e.g., functionalisation of the linker, crystallographic inequivalence and changes to the framework topology, while the relative proportion of each linker present can be obtained by comparing relative intensities of resonances corresponding to chemically-similar species in cross polarisation experiments with short contact times. Therefore, multinuclear NMR spectroscopy, and in particular the measurement of both isotropic and anisotropic parameters, offers a useful tool for the structural study of ordered and, in particular, disordered ZIFs.
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Affiliation(s)
- Scott Sneddon
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Jürgen Kahr
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Angelica F Orsi
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - David J Price
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Paul A Wright
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, St Andrews KY16 9ST, United Kingdom.
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49
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Pindelska E, Sokal A, Kolodziejski W. Pharmaceutical cocrystals, salts and polymorphs: Advanced characterization techniques. Adv Drug Deliv Rev 2017; 117:111-146. [PMID: 28931472 DOI: 10.1016/j.addr.2017.09.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/21/2017] [Accepted: 09/14/2017] [Indexed: 12/11/2022]
Abstract
The main goal of a novel drug development is to obtain it with optimal physiochemical, pharmaceutical and biological properties. Pharmaceutical companies and scientists modify active pharmaceutical ingredients (APIs), which often are cocrystals, salts or carefully selected polymorphs, to improve the properties of a parent drug. To find the best form of a drug, various advanced characterization methods should be used. In this review, we have described such analytical methods, dedicated to solid drug forms. Thus, diffraction, spectroscopic, thermal and also pharmaceutical characterization methods are discussed. They all are necessary to study a solid API in its intrinsic complexity from bulk down to the molecular level, gain information on its structure, properties, purity and possible transformations, and make the characterization efficient, comprehensive and complete. Furthermore, these methods can be used to monitor and investigate physical processes, involved in the drug development, in situ and in real time. The main aim of this paper is to gather information on the current advancements in the analytical methods and highlight their pharmaceutical relevance.
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50
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Dawson DM, Moran RF, Ashbrook SE. An NMR Crystallographic Investigation of the Relationships between the Crystal Structure and 29Si Isotropic Chemical Shift in Silica Zeolites. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:15198-15210. [PMID: 28751927 PMCID: PMC5523116 DOI: 10.1021/acs.jpcc.7b03730] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/16/2017] [Indexed: 05/26/2023]
Abstract
NMR crystallography has recently been applied to great effect for silica zeolites. Here we investigate whether it is possible to extend the structural information available from routine NMR spectra via a simple structure-spectrum relationship. Unlike previous empirically derived relationships that have compared experimental crystal structures for (often disordered) silicates with experimental NMR spectra, where the structure may not be an accurate representation of the material studied experimentally, we use NMR parameters calculated by density functional theory (DFT) for both model Si(OSi(OH)3)4 clusters and also extended zeolitic SiO2 frameworks, for which the input structure corresponding to the NMR parameters is known exactly. We arrive at a structure-spectrum relationship dependent on the mean Si-O bond length, mean Si-O-Si bond angle, and the standard deviations of both parameters, which can predict to within 1.3 ppm the 29Si isotropic magnetic shielding that should be obtained from a DFT calculation. While this semiempirical relationship will never supersede DFT where this is possible, it does open up the possibility of a rapid estimation of the outcome of a DFT calculation where the actual calculation would be prohibitively costly or otherwise challenging. We also investigate the structural optimization of SiO2 zeolites using DFT, demonstrating that the mean Si-O bond lengths all tend to 1.62 Å and the distortion index tends to <2.0°, suggesting that these metrics may be suitable for rapid validation of whether a given crystal structure represents a realistic local geometry around Si, or merely a bulk average with contributions from several different local geometries.
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