In situ solid-state NMR spectroscopy is exploited to monitor the structural evolution of a glycine/water glass phase formed on flash cooling an aqueous solution of glycine, with a range of modern solid-state NMR methods applied to elucidate structural properties of the solid phases present. The glycine/water glass is shown to crystallize into an intermediate phase, which then transforms to the β polymorph of glycine. Our in situ NMR results fully corroborate the identity of the intermediate crystalline phase as glycine dihydrate, which was first proposed only very recently.
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http://dx.doi.org/10.1002/anie.201801114 | DOI Listing |
Molecules
January 2025
Instituto Andaluz de Ciencias de la Tierra (IACT-CSIC), Consejo Superior de Investigaciones Científicas, Av. de las Palmeras 4, 18100 Armilla, Granada, Spain.
Many properties of 2,4-dichlorophenoxyacetic acid (2,4-D) depend on its molecular environment, such as whether it is an isolated molecule, a dimer, or in a crystalline state. The molecular geometry, conformational analysis, and vibrational spectrum of 2,4-D were theoretically calculated using Density Functional Theory (DFT) methods. A new slightly more stable conformer was found, which is different to those previously reported.
View Article and Find Full Text PDFMolecules
January 2025
Department of Chemistry and Biochemistry, State University of New York Brockport, Brockport, NY 14420, USA.
Non-ionic surfactants are an important solvent in the field of green chemistry with tremendous application potential. Understanding their phase properties in bulk or in confined environments is of high commercial value. In recent years, the combination of molecular dynamics (MD) simulations with multinuclear solid-state NMR spectroscopy and calorimetric techniques has evolved into the most powerful tool for their investigation.
View Article and Find Full Text PDFMolecules
January 2025
Centre for Surface Chemistry and Catalysis-Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium.
This work describes the synthesis of ordered 3D siloxane-silsesquioxane reticular materials with silicate D4R cubes (SiO), harvested from a sacrificial tetrabutylammonium cyclosilicate hydrate (TBA-CySH) precursor, interlinked with octyl and dicyclopentyl (Cp) hydrocarbon functionalities in a one-step synthesis with organodichlorosilanes. Advanced solid-state NMR spectroscopy allowed us to unravel the molecular order of the nodes and their interconnection by the silicone linkers. In the case of octyl-methyl silicone linkers, changing the silane-to-silicate ratio in the synthesis allowed for tuning the length of the linker between the nodes.
View Article and Find Full Text PDFAntibiotics (Basel)
January 2025
Departamento de Química, Faculdade de Ciências Exatas, Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Campus JK, Diamantina 39100-000, MG, Brazil.
This study investigates the structural and biophysical properties of the wild-type antimicrobial peptide LyeTx I, isolated from the venom of the spider , and its analog LyeTx I-b, designed to enhance antibacterial activity, selectivity, and membrane interactions by the acetylation and increased amphipathicty. : To understand the mechanisms behind these enhanced properties, comparative analyses of the structural, topological, biophysical, and thermodynamic aspects of the interactions between each peptide and phospholipid bilayers were evaluated. Both peptides were isotopically labeled with H-Ala and N-Leu to facilitate structural studies via NMR spectroscopy.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Polymers for Electronics and Photonics, Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, Prague 6 162 00, Czech Republic.
The structural response of 1,2-dimyristoyl-glycero-3-phosphatidylcholine (DMPC)/water bilayers to addition and subsequent solvation of a small amphiphilic molecule - an anesthetic benzyl alcohol - was studied by means of solid-state NMR (H NMR, P NMR) spectroscopy and low-angle X-ray diffraction. The sites of binding of this solute molecule within the bilayer were determined - the solute was shown to partition between several sites in the bilayer and the equilibrium was shown to be dynamic and dependent on the level of hydration and temperature. At the same time, it was shown that solubilization of benzyl alcohol reached a solubility limit and was terminated when the ordering profile of DMPC hydrocarbon chains adopted finite limiting values throughout the whole chain.
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