Article
Medicine, Research & Experimental
Keisuke Ueda, Kenjirou Higashi, Kunikazu Moribe
Summary: Cyclodextrin significantly affects the amorphous solubility of drugs, with DM-beta-CD having a greater impact on the IBP-rich phase.
MOLECULAR PHARMACEUTICS
(2021)
Article
Chemistry, Multidisciplinary
Andrei Filippov, Hilde Soenen, Johan Blom, Oleg N. Antzutkin
Summary: Self-diffusion in a bitumen emulsion was investigated using H-1 NMR. The emulsion consists of two phases: continuous and dispersed. The continuous aqueous phase contains mainly water and has the same activation energy for diffusion as bulk water but a lower diffusivity. The dispersed phase is made up of bitumen droplets containing confined water, and their diffusion is fully restricted in cavities with sizes around 0.11 μm. The observed bitumen emulsion can be described by a complex multiple emulsion model of water/oil/water (WOW) type.
Article
Nanoscience & Nanotechnology
Marco Schnurbus, Michael Hardt, Pascal Steinforth, Javier Carrascosa-Tejedor, Samuel Winnall, Philipp Gutfreund, Monika Schoenhoff, Richard A. Campbell, Bjoern Braunschweig
Summary: Light can trigger property changes in polyelectrolyte/surfactant mixtures, such as electrophoretic mobilities, particle size, interfacial structure, and foam stability.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Mechanical
C. C. Fraenza, E. Foerster, G. Guthausen, H. Nirschl, E. Anoardo
Summary: This study investigates the use of H-1 NMR spectroscopy, relaxation, and diffusion for characterizing the thermally-induced degradation of fresh motor oils. The results indicate that longitudinal and transverse relaxation are more sensitive to thermal effects, especially when measured at low magnetic fields using fast field-cycling NMR relaxometry.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Chemistry, Applied
Terri-Louise Hughes, Marta Falkowska, Markus Leutzsch, Andrew J. Sederman, Mick D. Mantle, Thomas F. Headen, Tristan G. A. Youngs, Daniel T. Bowron, Christopher Hardacre
Summary: The study investigates the structure and composition of mixtures of cyclohexane and benzene in different environments, revealing a stronger molecular orientational preference under confinement in mesopores.
TOPICS IN CATALYSIS
(2021)
Article
Materials Science, Multidisciplinary
L. Forzani, C. Antonio Hernandez, L. G. Cencha, H. Juarez Santiesteban, R. R. Koropecki, R. Urteaga
Summary: The study found that normal incidence birefringence in AAO is influenced by different crystal orientations of the aluminum substrate, which is important for the optical performance of optical devices. By using a simple thermo-mechanical treatment, better crystalline regions can be obtained to reduce the impact of birefringence. A simple model for elliptical section pores was proposed to quantitatively explain the origin of normal incidence birefringence in AAO.
Article
Chemistry, Physical
Veronique Nelis, Lorenz De Neve, Mathieu Balcaen, Koen Dewettinck, Timothee Courtin, Jose C. Martins, Paul Van Der Meeren
Summary: This study compared solid-fat based W/O emulsions with liquid-oil based W/O emulsions and found that water diffusion in solid-fat based W/O emulsions is hindered, leading to more accurate determination of water droplet size. The solid fat matrix may hinder extra-droplet water diffusion by increasing the tortuosity of the diffusive path.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Electrochemistry
Daniel Morales, Luciana Gomes Chagas, Domenec Paterno, Steve Greenbaum, Stefano Passerini, Sophia Suarez
Summary: Characterizing fundamental ion transport in various electrolytes, including binary and ternary solvents, revealed temperature-dependent behaviors of viscosity and ionic conductivity. NMR measurements showed cation-anion association at lower temperatures but diverged at higher temperatures, with the addition of FEC impacting local dynamics of solvents and ions differently.
ELECTROCHIMICA ACTA
(2021)
Review
Engineering, Chemical
Petrik Galvosas
Summary: This article introduces the use of NMR diffusometry to study samples in fields such as chemical engineering, soft matter research, environmental studies, and biology, in order to understand their material properties. This method, particularly NMR Diffusometry with Pulsed Field Gradients, is versatile and useful for studying complex and porous materials. The article showcases some recent applications, both within the context of Jorg Karger's work and beyond.
CHEMIE INGENIEUR TECHNIK
(2023)
Article
Chemistry, Multidisciplinary
Trent R. Graham, Jaehun Chun, Gregory K. Schenter, Xin Zhang, Sue B. Clark, Carolyn I. Pearce, Kevin M. Rosso
Summary: This study utilized Al-27 NMR spectroscopy to investigate the translational diffusion of epsilon-Al-13 clusters, demonstrating that symmetric Al environments can be probed using this method.
MAGNETIC RESONANCE IN CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Anna J. Parker, Arnab Dey, Mohammad Usman Qureshi, Jakob M. Steiner, John W. Blanchard, Jochen Scheuer, Nikolas Tomek, Stephan Knecht, Felix Josten, Christoph Mueller, Patrick Hautle, Ilai Schwartz, Patrick Giraudeau, Tim R. Eichhorn, Jean-Nicolas Dumez
Summary: The HYPNOESYS method, relying on the dissolution of optically polarized crystals, enhances the sensitivity of NMR spectroscopy in the solution state. This study demonstrates the acquisition of 2D NMR spectra from HYPNOESYS-polarized samples using single-scan methods, paving the way for a sensitive, information-rich, and affordable analytical technique.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Patrick Giraudeau
Summary: Complex mixtures are common in various fields of chemistry, presenting challenges in accurately quantifying their components. NMR spectroscopists have developed diverse approaches to tackle these challenges, including innovative pulse sequences, hyperpolarization methods, and processing tools. This article discusses the recent advances in quantitative NMR and their applications in pharmaceutical science, metabolomics, isotopic analysis, and monitoring.
CHEMICAL COMMUNICATIONS
(2023)
Review
Polymer Science
Nima Zohdi, Richard (Chunhui) Yang
Summary: Additive manufacturing (AM) is a sustainable and innovative technology used to fabricate products with specific properties and complex shapes. Challenges remain, such as material anisotropy, which requires exploration of methods to minimize its negative impact.
Article
Chemistry, Multidisciplinary
Na Sa, Sue-Sin Chong, Hui-Qiong Wang, Jin-Cheng Zheng
Summary: The anisotropy engineering of nanoporous zinc oxide (ZnO) frameworks has been studied using lattice dynamics simulation. Different sizes and shapes of nanopores were created to design a series of ZnO nanoporous framework structures. The effects of various features of the nanoporous framework on its mechanical properties were examined, and it was found that the anisotropy of the framework can be significantly tuned by changing the shape of the nanopores. The findings suggest a new route for desirable anisotropy and mechanical property engineering with nanoporous frameworks.
Article
Chemistry, Multidisciplinary
Heng Wang, Kun Wang, Yaping Xu, Wu Wang, Shaohua Chen, Matthew Hart, Lukasz Wojtas, Li-Peng Zhou, Lin Gan, Xuzhou Yan, Yiming Li, Juhoon Lee, Xian-Sheng Ke, Xu-Qing Wang, Chang-Wei Zhang, Shasha Zhou, Tianyou Zhai, Hai-Bo Yang, Ming Wang, Jiaqing He, Qing-Fu Sun, Bingqian Xu, Yang Jiao, Peter J. Stang, Jonathan L. Sessler, Xiaopeng Li
Summary: Parastichy, the spiral arrangement of plant organs, provides both an aesthetic challenge and a mathematical inspiration to scientists. Synthetic efforts to replicate its regularity may allow for molecular-scale control over particle arrangement processes. This study on the packing of a supramolecular truncated cuboctahedron into double-helical nanowires with a non-natural parastichy pattern is expected to advance understanding of designing complex, precisely controlled hierarchical materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
E. S. Kikkinides, G. Gkogkos, P. A. Monson, R. Valiullin
Summary: In this study, the relationship between density distributions encountered during the dynamics of capillary condensation and those distributions at equilibrium or metastable equilibrium was investigated. The states encountered were categorized as out of equilibrium or quasi-equilibrium based on the magnitude of the driving force for mass transfer.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Henry R. N. B. Enninful, Dirk Enke, Rustem Valiullin
Summary: This study compares phase transitions in mesoporous silica solids with different pore sizes, and finds that thermodynamic fluctuations become more important and have different effects on different equilibria as the pore size decreases.
Article
Chemistry, Physical
Seungtaik Hwang, Daniel Schneider, Jurgen Haase, Erich Miersemann, Jorg Karger
Summary: The use of hierarchically organized nanoporous materials effectively counteracts transport hindrance in micropores. This paper confirms the validity of the two-region approach of diffusion for mass transfer and catalytic conversion through comparison with kinetic Monte Carlo simulations.
Article
Chemistry, Multidisciplinary
Sergei S. Arzumanov, Anton A. Gabrienko, Dieter Freude, Juergen Haase, Alexander G. Stepanov
Summary: This article investigates the kinetics of H/D hydrogen exchange reactions using H-1 MAS NMR. The results show that the loading of Zn species can change the reaction mechanism from indirect exchange to direct exchange.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
A. Alzaidi, E. S. Kikkinides, D. Schneider, P. A. Monson, R. Valiullin
Summary: Adsorption/desorption and melting/freezing in structurally disordered nanoporous solids exhibit strongly non-equilibrium behavior. However, many questions related to the free energy spectrum, existence and accessibility of equilibrium transitions, and relaxation dynamics towards the global energy minimum, still remain poorly addressed. In this study, a minimal model of pore networks with statistical disorder is used to explore the system free energies along solid-liquid and liquid-gas transitions. The rigorous results obtained provide insights into the equilibrium transition line in porous solids with arbitrary pore topology.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Anton A. Gabrienko, Sergei S. Arzumanov, Alexander V. Toktarev, Igor P. Prosvirin, Dieter Freude, Juergen Haase, Alexander G. Stepanov
Summary: This study investigates the effect of different indium species on the conversion of propane on modified zeolites. It is found that the morphology of indium sites plays a crucial role in the activation and conversion pathways of propane.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Sergei S. Arzumanov, Anton A. Gabrienko, Alexander V. Toktarev, Dieter Freude, Jurgen Haase, Alexander G. Stepanov
Summary: The pathways of propane molecule activation on indium-modified zeolite were studied using 1H MAS NMR spectroscopy. The presence of indium species in the zeolite pores was found to provide regioselectivity in the H/D exchange of methyl groups of the propane molecule. The kinetics and activation energy of the exchange were also found to be influenced by the type of indium species present.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Hannes Preissler-Kurzhoefer, Andrei Kolesnikov, Marcus Lange, Jens Moellmer, Oliver Erhart, Merten Kobalz, Seungtaik Hwang, Christian Chmelik, Harald Krautscheid, Roger Glaeser
Summary: The rate of sorption of n-butane on a metal-organic framework was studied using sorption gravimetry, IR spectroscopy, and powder X-ray diffraction. The study revealed complex interactions of adsorption and structural transition, which depend on pressure step, temperature, particle size, and diffusion into newly opened pores. A kinetic model based on the linear driving force approach was used to independently study the rates of diffusion and structural transition.
Article
Chemistry, Physical
Jeremias C. Zill, Emma S. Thompson, Nikolaus Nestle, Rustem Valiullin
Summary: A nuclear magnetic resonance (NMR) study on amino-functionalized metal-organic framework (MOF) MIL-53(Al) revealed hysteresis in the structural transitions of pore opening/closing in response to methane pressure variation. The NMR signal intensities and transversal relaxation rates for methane showed broad pressure ranges for the transitions. Pressure reversals experiments provided insight into the microscopic transition mechanisms. These experiments confirmed that the observed non-stepwise transitions are governed by a distribution of opening/closing pressures in different MOF crystallites.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Review
Engineering, Chemical
Henry R. N. B. Enninful, Dirk Enke, Rustem Valiullin
Summary: Accurate structural characterization of mesoporous solids is of great importance for both potential applications and a better understanding of properties of natural porous materials. Among various characterization techniques, thermoporometry stands out for its applicability to wet and soft materials. This review discusses recent advancements in nuclear magnetic resonance cryoporometry, which significantly improves the accuracy of this method.
CHEMIE INGENIEUR TECHNIK
(2023)
Article
Chemistry, Physical
Eustathios S. Kikkinides, Rustem Valiullin
Summary: A new statistical theory is developed to describe adsorption and desorption in mesoporous materials represented by pore networks in the form of Bethe lattices, incorporating cooperative effects and pore connectivity. The theory is validated against simulations and algorithmic models, showing the impact of pore connectivity on condensation and evaporation processes in pore networks. This new theory offers a more accurate mimic of fluid behavior in real materials, providing a basis for extracting reliable pore size distributions.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Marija Avramovska, Dieter Freude, Wilhelm Schwieger, Tobias Fey, Jorg Kaerger, Juergen Haase
Summary: This study investigates the hydroxyl groups of ceramics fired at 800 degrees C using hydrothermal treatment. The rehydroxylation process between 600 and 200 C-degrees results in an increase of less than 1.5 times in the hydroxyl concentration. The findings contribute to a better understanding of the time elapsed since firing of ceramics.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Sergei S. Arzumanov, Anton A. Gabrienko, Alexander V. Toktarev, Dieter Freude, Ju''rgen Haase, Alexander G. Stepanov
Summary: The effect of indium species introduced in zeolite on the protolytic activation of alkane by zeolite Bronsted acid sites (BASs) was investigated. The results showed that the regioselectivity in the methyl groups of the alkane, high rate, and low activation energy were different when either InO+ or In+ cations were present in the zeolite compared to pure acid-form zeolites. The promoting effect of InO+ cations was found to be more essential than that of In+ cations.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Jeremias C. Zill, Emma S. Thompson, Nikolaus Nestle, Rustem Valiullin
Summary: A nuclear magnetic resonance (NMR) study shows that a pore opening occurs in amino-functionalized metal-organic framework (MOF) MIL-53(Al) in response to changes in methane pressure. Variations in NMR signal intensities and relaxation rates reveal hysteretic structural transitions in the MOF material, which are spread out over a broad pressure range. Additional experiments with pressure reversals provide insight into the microscopic transition mechanisms and confirm that the non-stepwise pore opening/closing transitions observed in the experiments are influenced by a distribution of opening/closing pressures across different MOF crystallites, possibly due to variations in crystal sizes or shapes. The slow kinetics of the structural transitions measured in the hysteresis regime highlight the complexity of the phase transition process.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)