Cp*Sc-X, where X is a halide, were synthesized and studied by solid-state Sc NMR to determine how the Sc-X bond affects quadrupolar NMR parameters. The experimental quadrupolar coupling constants (C) show that the fluoride has the largest coupling constant and that the iodide has the smallest coupling constant. DFT analysis of this data indicates that the C of these compounds is related to core scandium and halide orbitals, which is related to polarizability of the halide and the Sc-X distance. Cp*ScX(THF) were also investigated by solid-state Sc NMR spectroscopy, and have much smaller C values than the base-free halides. This is related to the change in structure of the THF adduct and occupation of orbitals of π-symmetry that reduce C.
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http://dx.doi.org/10.1039/c8dt02623h | DOI Listing |
Food Chem
January 2025
Department of Food Science, College of Light Industry, Liaoning University, Shenyang 110031, Liaoning Province, China; State Key Laboratory of Marine Food Processing and Safety Control, Dalian Polytechnic University, Dalian 116034, Liaoning Province, China; State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, Jiangxi Province, China. Electronic address:
Deep-fat frying (DF) of mushrooms is favored by consumers due to its appealing sensory characteristics. However, their high oil absorption can lead to obesity and elevated cholesterol levels. Therefore, developing healthy food coatings as oil barriers and water-holding layers is essential.
View Article and Find Full Text PDFScience
January 2025
Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford, UK.
The distribution of substitutional aluminum (Al) atoms in zeolites affects molecular adsorbate geometry, catalytic activity, and shape and size selectivity. Accurately determining Al positions has been challenging. We used synchrotron resonant soft x-ray diffraction (RSXRD) at multiple energies near the Al K-edge combined with molecular adsorption techniques to precisely locate "single Al" and "Al pairs" in a commercial H-ZSM-5 zeolite.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Centre of High Field NMR Spectroscopy and Imaging, Nanyang Technological University, 21 Nanyang Link, Singapore 637371.
The relationship among protein structure, function, and dynamics is fundamental to biological activity, particularly in more complex biomolecular systems. Solid-state and solution-state NMR techniques offer powerful means to probe these dynamics across various time scales. However, standard assumptions about molecular motion are often challenged in phase-separated systems like phosphorylated heterochromatin protein 1 alpha (pHP1α), which exhibit both solid- and solution-like characteristics.
View Article and Find Full Text PDFNat Commun
January 2025
NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
Membrane bound histidine kinases (HKs) are ubiquitous sensors of extracellular stimuli in bacteria. However, a uniform structural model is still missing for their transmembrane signaling mechanism. Here, we used solid-state NMR in conjunction with crystallography, solution NMR and distance measurements to investigate the transmembrane signaling mechanism of a paradigmatic citrate sensing membrane embedded HK, CitA.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemistry, Indian Institute of Technology Patna, Patna 801103, Bihar, India.
Polyoxometalates (POMs) are composed of nanometric metal-oxide anions and have rich solution chemistry. In this class, Keggin POMs have been identified as the most influential inorganic additives for aqueous nonionic soft matter systems. POMs being at the borderline of classical ions and charged colloids possess fascinating solution properties; the present work aims to delve deeper into the interactions between nanoions and nonionic soft matters from a spectroscopic point of view.
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