1
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Grunenberg L, Keßler C, Teh TW, Schuldt R, Heck F, Kästner J, Groß J, Hansen N, Lotsch BV. Probing Self-Diffusion of Guest Molecules in a Covalent Organic Framework: Simulation and Experiment. ACS NANO 2024; 18:16091-16100. [PMID: 38860455 PMCID: PMC11210340 DOI: 10.1021/acsnano.3c12167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 05/13/2024] [Accepted: 05/22/2024] [Indexed: 06/12/2024]
Abstract
Covalent organic frameworks (COFs) are a class of porous materials whose sorption properties have so far been studied primarily by physisorption. Quantifying the self-diffusion of guest molecules inside their nanometer-sized pores allows for a better understanding of confinement effects or transport limitations and is thus essential for various applications ranging from molecular separation to catalysis. Using a combination of pulsed field gradient nuclear magnetic resonance measurements and molecular dynamics simulations, we have studied the self-diffusion of acetonitrile and chloroform in the 1D pore channels of two imine-linked COFs (PI-3-COF) with different levels of crystallinity and porosity. The higher crystallinity and porosity sample exhibited anisotropic diffusion for MeCN parallel to the pore direction, with a diffusion coefficient of Dpar = 6.1(3) × 10-10 m2 s-1 at 300 K, indicating 1D transport and a 7.4-fold reduction in self-diffusion compared to the bulk liquid. This finding aligns with molecular dynamics simulations predicting 5.4-fold reduction, assuming an offset-stacked COF layer arrangement. In the low-porosity sample, more frequent diffusion barriers result in isotropic, yet significantly reduced diffusivities (DB = 1.4(1) × 10-11 m2 s-1). Diffusion coefficients for chloroform at 300 K in the pores of the high- (Dpar = 1.1(2) × 10-10 m2 s-1) and low-porosity (DB = 4.5(1) × 10-12 m2 s-1) samples reproduce these trends. Our multimodal study thus highlights the significant influence of real structure effects such as stacking faults and grain boundaries on the long-range diffusivity of molecular guest species while suggesting efficient intracrystalline transport at short diffusion times.
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Affiliation(s)
- Lars Grunenberg
- Max
Planck Institute for Solid State Research, Heisenbergstr. 1, Stuttgart 70569, Germany
- Department
of Chemistry, Ludwig-Maximilians-Universität
(LMU), Butenandtstr.
5-13, Munich 81377, Germany
| | - Christopher Keßler
- Institute
of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Pfaffenwaldring 9, Stuttgart 70569, Germany
| | - Tiong Wei Teh
- Institute
of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Pfaffenwaldring 9, Stuttgart 70569, Germany
| | - Robin Schuldt
- Institute
for Theoretical Chemistry, University of
Stuttgart, Pfaffenwaldring
55, Stuttgart 70569, Germany
| | - Fabian Heck
- Max
Planck Institute for Solid State Research, Heisenbergstr. 1, Stuttgart 70569, Germany
- Department
of Chemistry, Ludwig-Maximilians-Universität
(LMU), Butenandtstr.
5-13, Munich 81377, Germany
| | - Johannes Kästner
- Institute
for Theoretical Chemistry, University of
Stuttgart, Pfaffenwaldring
55, Stuttgart 70569, Germany
| | - Joachim Groß
- Institute
of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Pfaffenwaldring 9, Stuttgart 70569, Germany
| | - Niels Hansen
- Institute
of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Pfaffenwaldring 9, Stuttgart 70569, Germany
| | - Bettina V. Lotsch
- Max
Planck Institute for Solid State Research, Heisenbergstr. 1, Stuttgart 70569, Germany
- Department
of Chemistry, Ludwig-Maximilians-Universität
(LMU), Butenandtstr.
5-13, Munich 81377, Germany
- E-conversion, Lichtenbergstrasse 4a, Garching 85748, Germany
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2
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Ivanova S, Adamski P, Köster E, Schramm L, Fröhlich R, Beuerle F. Size Determination of Organic Cages by Diffusion NMR Spectroscopy. Chemistry 2023:e202303318. [PMID: 37966964 DOI: 10.1002/chem.202303318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 11/17/2023]
Abstract
Reliable structure elucidation of covalent organic cage compounds remains challenging as routine analysis might leave ambiguities. Diffusion-ordered NMR spectroscopy (DOSY) allows insight into the molecular size and mass of the species present in solution, but a systematic evaluation of the diffusion behavior for cage assemblies is rarely considered. Here we report the synthesis of four series of covalent organic cages based on tribenzotriquinacenes and diboronic acids with varying geometry and exohedral substituents. We provide a guideline for the consistent measurement of diffusion coefficients from 1 H-DOSY NMR spectroscopy, which was utilized to study the diffusion behavior for the whole set of cages and selected examples from the literature. For structurally similar cages, a linear correlation between the solvodynamic volume and the molecular mass allows precise size determination. For more complex systems, multiple parameters, such as window size or rigid exohedral functionalization. further modulate cage diffusion in solution.
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Affiliation(s)
- Svetlana Ivanova
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Paul Adamski
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Eva Köster
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Louis Schramm
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Rebecca Fröhlich
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Florian Beuerle
- Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074, Würzburg, Germany
- Eberhard Karls Universität Tübingen, Institut für Organische Chemie, Auf der Morgenstelle 18, 72076, Tübingen, Germany
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3
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Meo CD, Coviello T, Matricardi P, Lamanna R. Anomalous enhanced water diffusion in polysaccharide interpenetrating hydrogels. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2020.125892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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4
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New Insights to Characterize Paint Varnishes and to Study Water in Paintings by Nuclear Magnetic Resonance Spectroscopy (NMR). MAGNETOCHEMISTRY 2020. [DOI: 10.3390/magnetochemistry6020021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Paintings are complex multi-layered systems made of organic and inorganic materials. Several factors can affect the degradation of paintings, such as environmental conditions, past restoration works and, finally, the type of painting technique and the art materials used over the centuries. The chemical–physical characterization of paintings is a constant challenge that requires research into and the development of novel analytical methodologies and processes. In recent years, solvents and water-related issues in paintings are attracting more attention, and several studies have been focused on analyzing the interaction between water molecules and the constitutive materials. In this study, recent applications applying different NMR methodologies were shown, highlighting the weakness and the strength of the techniques in analyzing paintings. In particular, the study of water and its diffusive interactions within wall and oil paintings was performed to prove how the portable NMR can be used directly in museums for planning restoration work and to monitor the degradation processes. Furthermore, some preliminary results on the analysis of varnishes and binders, such us linseed oil, shellac, sandarac and colophony resins, were obtained by 1H HR-MAS NMR spectroscopy, highlighting the weakness and strengths of this technique in the field of conservation science.
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5
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Wu W, Klein T, Kerscher M, Rausch MH, Koller TM, Giraudet C, Fröba AP. Mutual and Thermal Diffusivities as well as Fluid-Phase Equilibria of Mixtures of 1-Hexanol and Carbon Dioxide. J Phys Chem B 2020; 124:2482-2494. [PMID: 32105484 DOI: 10.1021/acs.jpcb.0c00646] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work contributes to an improved understanding of the fluid-phase behavior and diffusion processes in mixtures of 1-hexanol and carbon dioxide (CO2) at temperatures around the upper critical end point (UCEP) of the system. Raman spectroscopy and dynamic light scattering were used to determine the composition at saturation conditions as well as Fick and thermal diffusivities. An acceleration of the Fick diffusive process up to CO2 mole fractions of about 0.2 was found, followed by a strong slowing-down approaching vapor-liquid-liquid equilibrium or critical conditions. The acceleration of the Fick diffusive process vanished at temperatures much higher than the UCEP. Experimental Fick diffusivity data were compared with predictions from equilibrium molecular dynamics simulations and excess Gibbs energy calculations using interaction parameters from the literature. Both theoretical methods were not able to predict that the thermodynamic factor is equal to zero at the spinodal composition, stressing the need for new methodologies under such conditions. Thus, new sets of temperature-dependent interaction parameters were developed for the nonrandom two-liquid model, which improve the prediction of the Fick diffusion coefficient considerably. The link between the Fick diffusion coefficient and the nonrandomness of the liquid phases is also discussed.
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Affiliation(s)
- Wenchang Wu
- Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 8, 91052 Erlangen, Germany
| | - Tobias Klein
- Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 8, 91052 Erlangen, Germany
| | - Manuel Kerscher
- Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 8, 91052 Erlangen, Germany
| | - Michael H Rausch
- Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 8, 91052 Erlangen, Germany
| | - Thomas M Koller
- Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 8, 91052 Erlangen, Germany
| | - Cédric Giraudet
- Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 8, 91052 Erlangen, Germany
| | - Andreas P Fröba
- Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering (CBI) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 8, 91052 Erlangen, Germany
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6
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Day IJ. Matrix-assisted DOSY. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 116:1-18. [PMID: 32130955 DOI: 10.1016/j.pnmrs.2019.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/30/2019] [Accepted: 09/01/2019] [Indexed: 06/10/2023]
Abstract
The analysis of mixtures by NMR spectroscopy is challenging. Diffusion-ordered NMR spectroscopy enables a pseudo-separation of species based on differences in their translational diffusion coefficients. Under the right circumstances, this is a powerful technique; however, when molecules diffuse at similar rates separation in the diffusion dimension can be poor. In addition, spectral overlap also limits resolution and can make interpretation challenging. Matrix-assisted diffusion NMR seeks to improve resolution in the diffusion dimension by utilising the differential interaction of components in the mixture with an additive to the solvent. Tuning these matrix-analyte interactions allows the diffusion resolution to be optimised. This review presents the background to matrix-assisted diffusion experiments, surveys the wide range of matrices employed, including chromatographic stationary phases, surfactants and polymers, and demonstrates the current state of the art.
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Affiliation(s)
- Iain J Day
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QJ, UK.
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7
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Baz J, Hansen N, Gross J. Transferable Anisotropic Mie-Potential Force Field for n-Alcohols: Static and Dynamic Fluid Properties of Pure Substances and Binary Mixtures. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b05323] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jörg Baz
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, 70569 Stuttgart, Germany
| | - Niels Hansen
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, 70569 Stuttgart, Germany
| | - Joachim Gross
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, 70569 Stuttgart, Germany
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8
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Di Tullio V, Zumbulyadis N, Centeno SA, Catalano J, Wagner M, Dybowski C. Water Diffusion and Transport in Oil Paints as Studied by Unilateral NMR and
1
H High‐Resolution MAS‐NMR Spectroscopy. Chemphyschem 2019; 21:113-119. [DOI: 10.1002/cphc.201900858] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Valeria Di Tullio
- Department of Scientific Research The Metropolitan Museum of Art New York, NY USA
- Magnetic Resonance Laboratory “Annalaura Segre” ISB-CNR Rome Italy
| | - Nicholas Zumbulyadis
- Independent Researcher, Rochester NY USA
- Department of Chemistry and Biochemistry University of Delaware Newark, DE USA
| | - Silvia A. Centeno
- Department of Scientific Research The Metropolitan Museum of Art New York, NY USA
| | - Jaclyn Catalano
- Department of Chemistry and Biochemistry Montclair State University Montclair, NJ USA
| | - Molly Wagner
- Department of Chemistry and Biochemistry University of Delaware Newark, DE USA
| | - Cecil Dybowski
- Department of Chemistry and Biochemistry University of Delaware Newark, DE USA
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9
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Mouchaham G, Roques N, Khodja W, Duhayon C, Coppel Y, Brandès S, Fodor T, Meyer M, Sutter JP. Hydrogen-Bonded Open-Framework with Pyridyl-Decorated Channels: Straightforward Preparation and Insight into Its Affinity for Acidic Molecules in Solution. Chemistry 2017; 23:11818-11826. [DOI: 10.1002/chem.201701732] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Georges Mouchaham
- CNRS; LCC (Laboratoire de Chimie de Coordination); 205 route de Narbonne 31077 Toulouse France
- Université de Toulouse, UPS, INPT; 31077 Toulouse France
| | - Nans Roques
- CNRS; LCC (Laboratoire de Chimie de Coordination); 205 route de Narbonne 31077 Toulouse France
- Université de Toulouse, UPS, INPT; 31077 Toulouse France
| | - Walid Khodja
- CNRS; LCC (Laboratoire de Chimie de Coordination); 205 route de Narbonne 31077 Toulouse France
- Université de Toulouse, UPS, INPT; 31077 Toulouse France
| | - Carine Duhayon
- CNRS; LCC (Laboratoire de Chimie de Coordination); 205 route de Narbonne 31077 Toulouse France
- Université de Toulouse, UPS, INPT; 31077 Toulouse France
| | - Yannick Coppel
- CNRS; LCC (Laboratoire de Chimie de Coordination); 205 route de Narbonne 31077 Toulouse France
- Université de Toulouse, UPS, INPT; 31077 Toulouse France
| | - Stéphane Brandès
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS; Université de Bourgogne-Franche-Comté; 9 avenue Alain Savary, BP 47870 21078 Dijon Cedex France
| | - Tamás Fodor
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS; Université de Bourgogne-Franche-Comté; 9 avenue Alain Savary, BP 47870 21078 Dijon Cedex France
| | - Michel Meyer
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS; Université de Bourgogne-Franche-Comté; 9 avenue Alain Savary, BP 47870 21078 Dijon Cedex France
| | - Jean-Pascal Sutter
- CNRS; LCC (Laboratoire de Chimie de Coordination); 205 route de Narbonne 31077 Toulouse France
- Université de Toulouse, UPS, INPT; 31077 Toulouse France
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10
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Ramalhete SM, Nartowski KP, Sarathchandra N, Foster JS, Round AN, Angulo J, Lloyd GO, Khimyak YZ. Supramolecular Amino Acid Based Hydrogels: Probing the Contribution of Additive Molecules using NMR Spectroscopy. Chemistry 2017; 23:8014-8024. [PMID: 28401991 PMCID: PMC5575562 DOI: 10.1002/chem.201700793] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Indexed: 11/08/2022]
Abstract
Supramolecular hydrogels are composed of self-assembled solid networks that restrict the flow of water. l-Phenylalanine is the smallest molecule reported to date to form gel networks in water, and it is of particular interest due to its crystalline gel state. Single and multi-component hydrogels of l-phenylalanine are used herein as model materials to develop an NMR-based analytical approach to gain insight into the mechanisms of supramolecular gelation. Structure and composition of the gel fibres were probed using PXRD, solid-state NMR experiments and microscopic techniques. Solution-state NMR studies probed the properties of free gelator molecules in an equilibrium with bound molecules. The dynamics of exchange at the gel/solution interfaces was investigated further using high-resolution magic angle spinning (HR-MAS) and saturation transfer difference (STD) NMR experiments. This approach allowed the identification of which additive molecules contributed in modifying the material properties.
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Affiliation(s)
| | - Karol P. Nartowski
- School of PharmacyUniversity of East AngliaNorwich Research ParkNR4 7TJUK
- Current address: Department of Drug Form TechnologyFaculty of PharmacyWroclaw Medical Universityul. Borowska 21150-556WroclawPoland
| | | | - Jamie S. Foster
- Institute of Chemical Sciences, School of Engineering and Physical SciencesHeriot-Watt UniversityEH14 4ASUK
| | - Andrew N. Round
- School of PharmacyUniversity of East AngliaNorwich Research ParkNR4 7TJUK
| | - Jesús Angulo
- School of PharmacyUniversity of East AngliaNorwich Research ParkNR4 7TJUK
| | - Gareth O. Lloyd
- Institute of Chemical Sciences, School of Engineering and Physical SciencesHeriot-Watt UniversityEH14 4ASUK
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11
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Lucena Alcalde G, Anderson N, Day IJ. Size-exclusion chromatographic NMR under HR-MAS. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:485-491. [PMID: 27306190 DOI: 10.1002/mrc.4464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 05/17/2016] [Accepted: 05/25/2016] [Indexed: 06/06/2023]
Abstract
The addition of stationary phases or sample modifiers can be used to modify the separation achievable in the diffusion domain of diffusion NMR experiments or provide information on the nature of the analyte-sample modifier interaction. Unfortunately, the addition of insoluble chromatographic stationary phases can lead to line broadening and degradation in spectral resolution, largely because of differences in magnetic susceptibility between the sample and the stationary phase. High-resolution magic angle spinning (HR-MAS) techniques can be used to remove this broadening. Here, we attempt the application of HR-MAS to size-exclusion chromatographic NMR with limited success. Observed diffusion coefficients for polymer molecular weight reference standards are shown to be larger than those obtained on static samples. Further investigation reveals that under HR-MAS it is possible to obtain reasonably accurate estimates of diffusion coefficients, using either full rotor synchronisation or sophisticated pulse sequences. The requirement for restricting the sample to the centre of the MAS rotor to ensure homogeneous magnetic and RF fields is also tested. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
| | | | - Iain J Day
- School of Life Sciences, University of Sussex, Brighton, UK
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12
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Ferreira ASD, Barreiros S, Cabrita EJ. Probing sol-gel matrices microenvironments by PGSE HR-MAS NMR. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:452-463. [PMID: 26987451 DOI: 10.1002/mrc.4427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/28/2016] [Accepted: 02/10/2016] [Indexed: 06/05/2023]
Abstract
We applied Pulsed Gradient Spin Echo diffusion with high-resolution magic angle spinning NMR to study sol-gel matrices used to encapsulate enzymes for biocatalysis (TMOS/MTMS and TMOS/BTMS) to gain insight into the local chemical microenvironment. Transport properties of solvents with different polarities (1-pentanol, acetonitrile and n-hexane) were studied through their apparent self-diffusion coefficients. The spin echo attenuation of the solvents shows two distinct diffusion domains, one with fast diffusion (Dfast ) associated with interparticle diffusion and another with slow diffusion (Dslow ) corresponding to the displacement inside the pores within the sol-gel particles. The analysis of the root mean square displacements at different diffusion times showed that the Dfast domain has a free diffusion regime in both matrices (the root mean square displacement is linearly dependent of the diffusion time), while the Dslow domain shows a different regime that depends on the matrix. We investigated the exchange regime between the two diffusion sites. In both matrices, n-hexane was in intermediate exchange between diffusion domains, while the polar solvents were in slow exchange in TMOS/BTMS and in intermediate exchange in TMOS/MTMS. Data were fitted for TMOS/BTMS with the Kärger model, and the physical parameters were obtained. The results add to the evidence that the pores are a hydrophobic environment but that the presence of some free hydrophilic groups inside the pore, as observed in the TMOS/BTMS, has a key role in slowing down the exchange of polar solvents and that this is relevant to explain previously reported enzyme activity in these materials. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Ana S D Ferreira
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Centro de Química Estrutural, Instituto Superior Técnico, Lisboa, Portugal
| | - Susana Barreiros
- LAQV, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Eurico J Cabrita
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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13
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González-García T, Margola T, Silvagni A, Mancin F, Rastrelli F. Chromatographic NMR Spectroscopy with Hollow Silica Spheres. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Tania González-García
- Organic and Inorganic Chemistry Departament; University of Oviedo; c/ Julián Clavería, no. 8 Oviedo 33006 Spain
| | - Tommaso Margola
- Department of Chemical Sciences; Università degli Studi di Padova; via Marzolo 1 35131 Padova Italy
| | - Adriano Silvagni
- Department of Chemical Sciences; Università degli Studi di Padova; via Marzolo 1 35131 Padova Italy
| | - Fabrizio Mancin
- Department of Chemical Sciences; Università degli Studi di Padova; via Marzolo 1 35131 Padova Italy
| | - Federico Rastrelli
- Department of Chemical Sciences; Università degli Studi di Padova; via Marzolo 1 35131 Padova Italy
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14
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González-García T, Margola T, Silvagni A, Mancin F, Rastrelli F. Chromatographic NMR Spectroscopy with Hollow Silica Spheres. Angew Chem Int Ed Engl 2016; 55:2733-7. [DOI: 10.1002/anie.201510203] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/21/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Tania González-García
- Organic and Inorganic Chemistry Departament; University of Oviedo; c/ Julián Clavería, no. 8 Oviedo 33006 Spain
| | - Tommaso Margola
- Department of Chemical Sciences; Università degli Studi di Padova; via Marzolo 1 35131 Padova Italy
| | - Adriano Silvagni
- Department of Chemical Sciences; Università degli Studi di Padova; via Marzolo 1 35131 Padova Italy
| | - Fabrizio Mancin
- Department of Chemical Sciences; Università degli Studi di Padova; via Marzolo 1 35131 Padova Italy
| | - Federico Rastrelli
- Department of Chemical Sciences; Università degli Studi di Padova; via Marzolo 1 35131 Padova Italy
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15
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Abstract
Matrix-assisted diffusion-ordered NMR spectroscopy has the potential to transform mixture analysis by DOSY NMR.
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Affiliation(s)
- Robert Evans
- Chemical Engineering and Applied Chemistry
- Aston University
- Birmingham
- UK
| | - Iain J. Day
- School of Life Sciences
- University of Sussex
- Brighton BN1 9QJ
- UK
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16
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Pasquini L, Ziarelli F, Viel S, Di Vona ML, Knauth P. Fluoride-ion-conducting Polymers: Ionic Conductivity and Fluoride Ion Diffusion Coefficient in Quaternized Polysulfones. Chemphyschem 2015; 16:3631-6. [DOI: 10.1002/cphc.201500643] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Luca Pasquini
- Aix Marseille University, CNRS; MADIREL (UMR 7246); Campus St Jerome F-13397 Marseille France
- University of Rome Tor Vergata; Department of Chemical Sciences and Technologies; Via della Ricerca Scientifica 1 00133 Roma Italy
| | - Fabio Ziarelli
- Aix Marseille University, Centrale Marseille, CNRS; Fédération des Sciences Chimiques de Marseille (FR 1739); Campus St Jerome F-13397 Marseille France
| | - Stéphane Viel
- Aix Marseille University, CNRS; Institut de Chimie Radicalaire (UMR 7273); Campus St Jerome F-13397 Marseille France
- Institut Universitaire de France; 75000 Paris France
| | - Maria Luisa Di Vona
- University of Rome Tor Vergata; Department of Chemical Sciences and Technologies; Via della Ricerca Scientifica 1 00133 Roma Italy
| | - Philippe Knauth
- Aix Marseille University, CNRS; MADIREL (UMR 7246); Campus St Jerome F-13397 Marseille France
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17
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Henoumont C, Laurent S, Muller RN, Vander Elst L. HR-MAS NMR Spectroscopy: An Innovative Tool for the Characterization of Iron Oxide Nanoparticles Tracers for Molecular Imaging. Anal Chem 2015; 87:1701-10. [DOI: 10.1021/ac5035105] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Céline Henoumont
- Department
of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging
Laboratory, University of Mons, 19 Avenue Maistriau, B-7000 Mons, Belgium
| | - Sophie Laurent
- Department
of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging
Laboratory, University of Mons, 19 Avenue Maistriau, B-7000 Mons, Belgium
| | - Robert N. Muller
- Department
of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging
Laboratory, University of Mons, 19 Avenue Maistriau, B-7000 Mons, Belgium
- Center
for Microscopy
and Molecular Imaging (CMMI), 8 Rue
Adrienne Boland, 6041 Gosselies, Belgium
| | - Luce Vander Elst
- Department
of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging
Laboratory, University of Mons, 19 Avenue Maistriau, B-7000 Mons, Belgium
- Center
for Microscopy
and Molecular Imaging (CMMI), 8 Rue
Adrienne Boland, 6041 Gosselies, Belgium
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18
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Moreira G, Fedeli E, Ziarelli F, Capitani D, Mannina L, Charles L, Viel S, Gigmes D, Lefay C. Synthesis of polystyrene-grafted cellulose acetate copolymers via nitroxide-mediated polymerization. Polym Chem 2015. [DOI: 10.1039/c5py00752f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cellulose acetate-g-polystyrene grafted copolymers have been synthesized by NMP under homogeneous conditions by using the 1,2-intermolecular radical addition methodology.
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Affiliation(s)
- Guillaume Moreira
- Aix Marseille Université
- CNRS
- Institut de Chimie Radicalaire UMR 7273
- 13397 Marseille Cedex 20
- France
| | - Elisabetta Fedeli
- Aix Marseille Université
- CNRS
- Institut de Chimie Radicalaire UMR 7273
- 13397 Marseille Cedex 20
- France
| | - Fabio Ziarelli
- Aix Marseille Université
- Centrale Marseille
- CNRS
- Fédération des Sciences Chimiques FR 1739
- F-13397 Marseille
| | - Donatella Capitani
- Laboratorio NMR “Annalaura Segre”
- Istituto di Metodologie Chimiche
- Centro Nazionale delle Ricerche
- I-00015 Monterotondo
- Italy
| | - Luisa Mannina
- Laboratorio NMR “Annalaura Segre”
- Istituto di Metodologie Chimiche
- Centro Nazionale delle Ricerche
- I-00015 Monterotondo
- Italy
| | - Laurence Charles
- Aix Marseille Université
- CNRS
- Institut de Chimie Radicalaire UMR 7273
- 13397 Marseille Cedex 20
- France
| | - Stéphane Viel
- Aix Marseille Université
- CNRS
- Institut de Chimie Radicalaire UMR 7273
- 13397 Marseille Cedex 20
- France
| | - Didier Gigmes
- Aix Marseille Université
- CNRS
- Institut de Chimie Radicalaire UMR 7273
- 13397 Marseille Cedex 20
- France
| | - Catherine Lefay
- Aix Marseille Université
- CNRS
- Institut de Chimie Radicalaire UMR 7273
- 13397 Marseille Cedex 20
- France
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19
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Lucena Alcalde G, Joyce RE, Day IJ. Size-exclusion chromatographic NMR of polymer mixtures. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2014; 52:760-763. [PMID: 25155543 DOI: 10.1002/mrc.4127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/17/2014] [Accepted: 07/27/2014] [Indexed: 06/03/2023]
Abstract
The use of chromatographic stationary phases or solvent modifiers to modulate diffusion properties in NMR experiments is now well established. Their use can be to improve resolution in the diffusion domain or to provide an insight into analyte-modifier interactions and, hence, the chromatography process. Here, we extend previous work using size-exclusion chromatographic stationary phases to the investigation of polymer mixtures. We demonstrate that similar diffusion modulation behaviour is observed with a size-exclusion chromatographic stationary phase that can be understood in terms of size-exclusion behaviour.
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20
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Barreira G, Ferreira ASD, Vidinha P, Cabral JMS, Martinho JMG, Lima JC, Cabrita EJ, Barreiros S. Assessing diffusion in enzyme loaded sol–gel matrices. RSC Adv 2014. [DOI: 10.1039/c4ra01620c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Assessing the diffusion of solvent and reaction species within a sol–gel matrix using pulsed field gradient spin echo HR-MAS NMR.
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Affiliation(s)
- Gustavo Barreira
- REQUIMTE/CQFB
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- 2829-516 Caparica, Portugal
| | - Ana S. D. Ferreira
- REQUIMTE/CQFB
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- 2829-516 Caparica, Portugal
| | - Pedro Vidinha
- REQUIMTE/CQFB
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- 2829-516 Caparica, Portugal
| | - Joaquim M. S. Cabral
- Department of Bioengineering and IBB - Institute for Biotechnology and Bioengineering
- Instituto Superior Técnico (IST)
- Lisboa, Portugal
| | - José M. G. Martinho
- Centro de Química-Física Molecular
- Instituto Superior Técnico
- 1049-001 Lisboa, Portugal
| | - João Carlos Lima
- REQUIMTE/CQFB
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- 2829-516 Caparica, Portugal
| | - Eurico J. Cabrita
- REQUIMTE/CQFB
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- 2829-516 Caparica, Portugal
| | - Susana Barreiros
- REQUIMTE/CQFB
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
- 2829-516 Caparica, Portugal
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21
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Asakura T, Suzuki Y, Nakazawa Y, Yazawa K, Holland GP, Yarger JL. Silk structure studied with nuclear magnetic resonance. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 69:23-68. [PMID: 23465642 DOI: 10.1016/j.pnmrs.2012.08.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 08/13/2012] [Indexed: 06/01/2023]
Affiliation(s)
- Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
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22
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Maid H, Heinemann FW, Scheurer A, Mooren N, Saalfrank RW, Bauer W. Dynamic Phenomena in Self-Complementary {2}-Metallocryptates Probed by Solution133Cs-NMR. New Insights into Ion Pairing Processes: X-Ray Structure and Solid-State NMR Spectra of a Meandering Species. Helv Chim Acta 2012. [DOI: 10.1002/hlca.201200494] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Carrara C, Lopez C, Caldarelli S. Chromatographic-nuclear magnetic resonance can provide a prediction of high-pressure liquid chromatography shape selectivity tests. J Chromatogr A 2012; 1257:204-7. [DOI: 10.1016/j.chroma.2012.07.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/09/2012] [Accepted: 07/10/2012] [Indexed: 10/28/2022]
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24
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Jenkins JE, Hibbs MR, Alam TM. Identification of Multiple Diffusion Rates in Mixed Solvent Anion Exchange Membranes Using High Resolution MAS NMR. ACS Macro Lett 2012; 1:910-914. [PMID: 35607143 DOI: 10.1021/mz300124j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
High resolution magic angle spinning (HRMAS) 1H NMR in combination with 2D exchange NOESY and pulsed field gradient (PFG) NMR diffusion experiments have been used to characterize 1 N methanol swollen polymer anion exchange membranes (AEM) presently being developed for alkaline fuel cells. Standard static 1H NMR experiments on these materials have proven unsuccessful due to severe signal broadening. New experimental methods for increased resolution are needed to determine distinct solvent environments and transport properties. Using HRMAS NMR, resonances from water and methanol in both a free (bulk-like) environment and membrane-associated environment within the AEM were observed. 1H HRMAS PFG NMR experiments identified different molecular diffusion environments in the solvent, while 1H 2D NOESY exchange NMR experiments confirmed spatial contacts between membrane-associated species and the membrane. These results demonstrate that 1H HRMAS is an ideal technique for the characterization of individual environments and diffusion rates in polymer membranes with mixed solvent systems.
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Affiliation(s)
- Janelle E. Jenkins
- Department
of Electronic and Nanostructured Materials and ‡Department of Materials, Devices,
and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87123, United
States
| | - Michael R. Hibbs
- Department
of Electronic and Nanostructured Materials and ‡Department of Materials, Devices,
and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87123, United
States
| | - Todd M. Alam
- Department
of Electronic and Nanostructured Materials and ‡Department of Materials, Devices,
and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87123, United
States
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25
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Joyce RE, Day IJ. Chromatographic NMR with size exclusion chromatography stationary phases. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 220:1-7. [PMID: 22683575 DOI: 10.1016/j.jmr.2012.04.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/23/2012] [Accepted: 04/29/2012] [Indexed: 06/01/2023]
Abstract
Chromatographic NMR describes the use of stationary phases or solvent additives, such as polymers, to modify the diffusion properties of analyte molecules and thereby improve the observed resolution in the diffusion domain. This paper demonstrates similar ideas using size exclusion chromatographic media and characterises the changes in the observed diffusion coefficient using a series of polymer molecular weight reference standards of known polydispersity. The results are interpreted in terms of a simple description of the size exclusion phenomena.
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Affiliation(s)
- Rebecca E Joyce
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QJ, UK
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26
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Ziarelli F, Peng L, Zhang CC, Viel S. High resolution magic angle spinning NMR to investigate ligand–receptor binding events for mass-limited samples in liquids. J Pharm Biomed Anal 2012; 59:13-7. [DOI: 10.1016/j.jpba.2011.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 10/09/2011] [Accepted: 10/10/2011] [Indexed: 11/29/2022]
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27
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Shukla M, Dorai K. Resolving overlaps in diffusion encoded spectra using band-selective pulses in a 3D BEST-DOSY experiment. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 213:69-75. [PMID: 21937251 DOI: 10.1016/j.jmr.2011.08.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 08/10/2011] [Accepted: 08/30/2011] [Indexed: 05/31/2023]
Abstract
A novel diffusion-edited 3D NMR experiment that incorporates a BEST-HMQC pulse sequence in its implementation is presented. Heteronuclear 3D DOSY NMR experiments are useful in elucidating the diffusion coefficients of individual constituents of a mixture, especially in cases where the proton NMR 2D DOSY spectra show considerable overlap. The present 3D BEST-DOSY pulse sequence provides a more sensitive and less time-consuming alternative to standard 3D HMQC-DOSY experiments. Cleanly separated subspectra of individual mixture components are obtained, leading to the determination of diffusion coefficients with better accuracy. The feasibility of the technique is demonstrated on a mixture of amino acids, on a mixture of small molecules with similar diffusion coefficients, and on a complex mixture with large dynamic range (commercial gasoline). The implications of using adiabatic decoupling schemes and band-selective shaped pulses for selective BEST-DOSY experiments on proteins are also discussed.
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Affiliation(s)
- Matsyendranath Shukla
- Department of Physics, Indian Institute of Science Education & Research (IISER) Mohali, Chandigarh 160 019, India.
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28
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Pemberton C, Hoffman RE, Aserin A, Garti N. NMR chromatography using microemulsion systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:4497-4504. [PMID: 21405070 DOI: 10.1021/la200232b] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
NMR spectroscopy is an excellent tool for structural analysis of pure compounds. However, for mixtures, it performs poorly because of overlapping signals. Diffusion ordered NMR spectroscopy (DOSY) can be used to separate the spectra of compounds with widely differing molecular weights, but the separation is usually insufficient. NMR "chromatographic" methods have been developed to increase the diffusion separation but these usually introduced solids into the NMR sample that reduce resolution. Using nanostructured dispersed media, such as microemulsions, eliminates the need for suspensions of solids and brings NMR chromatography into the mainstream of NMR analytical techniques. DOSY was used in this study to resolve spectra of mixtures with no increase in line-width as compared to regular solutions. Components of a mixture are differentially dissolved into the separate phases of the microemulsions. Several examples of previously reported microemulsions and those specifically developed for this purpose were used here. These include a fully dilutable microemulsion, a fluorinated microemulsion, and a fully deuterated microemulsion. Log(diffusion) difference enhancements of up to 1.7 orders of magnitude were observed for compounds that have similar diffusion rates in conventional solvents. Examples of commercial pharmaceutical drugs were also analyzed via this new technique, and the spectra of up to six components were resolved from one sample.
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Affiliation(s)
- Chava Pemberton
- The Ratner Family Chair of Chemistry, Casali Institute of Applied Chemistry, Institute of Chemistry, Edmond J. Safra Campus, Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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29
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Pemberton C, Hoffman R, Aserin A, Garti N. New insights into silica-based NMR "chromatography". JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 208:262-269. [PMID: 21195647 DOI: 10.1016/j.jmr.2010.11.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 10/06/2010] [Accepted: 11/18/2010] [Indexed: 05/30/2023]
Abstract
Silica is used as an important component for NMR "chromatography". In this study the effect of the binding strength to silica of a variety of compounds on their diffusion rate is measured for the first time. Over two orders of magnitude of diffusion difference enhancement was obtained in the presence of silica for some compounds. An explanation of the enhancement is given that also allows one to predict the "chromatographic" behavior of new compounds or mixtures. The binding strength is divided into categories of weakly bound, singly bound and multiply bound. Carboxylates, sulfonates, and diols are found to be particularly strongly bound and to diffuse up to 2½ orders of magnitude more slowly in the presence of silica.
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Affiliation(s)
- Chava Pemberton
- Casali Institute of Applied Chemistry, The Institute of Chemistry, Edmond J. Safra Campus, Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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30
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Romanova EE, Grinberg F, Pampel A, Kärger J, Freude D. Diffusion studies in confined nematic liquid crystals by MAS PFG NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 196:110-114. [PMID: 19006677 DOI: 10.1016/j.jmr.2008.10.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 10/14/2008] [Accepted: 10/14/2008] [Indexed: 05/27/2023]
Abstract
Pulsed field gradient (PFG) NMR and magic-angle spinning (MAS) NMR have been combined in order to measure the diffusion coefficients of liquid crystals in confined geometry. Combination of MAS NMR with PFG NMR has a higher spectroscopic resolution in comparison with conventional PFG NMR and improves the application of NMR diffusometry to liquid crystals. It is found that the confinement of the liquid crystal 5CB in porous glasses with mean pore diameters of 30 and 200 nm does not notably change its diffusion behavior in comparison with the bulk state.
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Affiliation(s)
- Ekaterina E Romanova
- Abteilung Grenzflächenphysik, Universität Leipzig, Linnéstr. 5, 04103 Leipzig, Germany.
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31
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Carrara C, Viel S, Delaurent C, Ziarelli F, Excoffier G, Caldarelli S. Chromatographic NMR in NMR solvents. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 194:303-306. [PMID: 18678513 DOI: 10.1016/j.jmr.2008.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 07/01/2008] [Accepted: 07/10/2008] [Indexed: 05/26/2023]
Abstract
Recently, it was demonstrated that pseudo-chromatographic NMR experiments could be performed using typical chromatographic solids and solvents. This first setup yielded improved separation of the spectral components of the NMR spectra of mixtures using PFG self-diffusion measurements. The method (dubbed Chromatographic NMR) was successively shown to possess, in favorable cases, superior resolving power on non-functionalized silica, compared to its LC counterpart. To further investigate the applicability of the method, we studied here the feasibility of Chromatographic NMR in common deuterated solvents. Two examples are provided, using deuterated chloroform and water, for homologous compounds soluble in these solvents, namely aromatic molecules and alcohols, respectively.
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Affiliation(s)
- Caroline Carrara
- ISm2 UMR 6263, Aix Marseille Université, Campus Saint Jérôme, 13013 Marseille, France
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