The chromatographic behavior of model ions of biomedical and environmental significance was investigated by using nonionic micellar mobile phases modified with ion-pair additives. The influence of concentrations of polyoxyethylene (23) lauryl ether and ornithine hydrochloride in the mobile phase on the retention factors of chromium (III), chromium (VI), iodide and bromide ions was studied. The possible mechanisms of retention of the mentioned ions in biopartitioning micellar chromatography with zwitter ion-pair additives were proposed.
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http://dx.doi.org/10.1002/bmc.1446 | DOI Listing |
J Am Chem Soc
January 2025
School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia.
Designing molecular receptors that bind anions in water is a significant challenge, and an even greater difficulty lies in using these receptors to remove anions from water without resorting to the hazardous liquid-liquid extraction approach. We here demonstrate an effective and synthetically simple strategy toward these goals by exploiting ion-pair assembly of macrocycles. Our anion binding ensemble consists of an octa-chloro tetra-urea macrocyclic anion receptor (ClTU), which forms water-dispersible aggregates, and a tetra-cationic fluorescent dye 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin (TMPyP4), which provides Coulombic stabilization and fluorescence reporting of anion binding in an ion-pair assembly.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Institute of Organic Chemistry, University Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany.
In ion-pair catalysis, the last intermediate structures prior to the stereoselective transition states are of special importance for predictive models due to the high isomerization barrier between - and -substrate double bonds connecting ground and transition state energies. However, in prior experimental investigations of chiral phosphoric acids (CPA) solely the early intermediates could be investigated while the key intermediate remained elusive. In this study, the first experimental structural and conformational insights into ternary complexes with CPAs are presented using a special combination of low temperature and relaxation optimized N HSQC-NOESY NMR spectroscopy to enhance sensitivity.
View Article and Find Full Text PDFChem Sci
December 2024
Institut für Physikalische und Theoretische Chemie, Universität Regensburg 93040 Regensburg Germany +49 941 943 4487.
Photoacids undergo an increase in acidity upon electronic excitation, enabling excited-state proton transfer (ESPT) reactions. A multitude of compounds that allow ESPT has been identified and integrated in numerous applications, as is outlined by reviewing the rich history of photoacid research reaching back more than 90 years. In particular, achievements together with ambitions and challenges are highlighted from a combined experimental and theoretical perspective.
View Article and Find Full Text PDFJACS Au
December 2024
Laboratory of Energy Science and Engineering, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, 8092 Zürich, Switzerland.
There is an urgent need for inexpensive, functional materials that can capture and release CO under industrial conditions. In this context, MgO is a highly promising, earth-abundant CO sorbent. However, despite its favorable carbonation thermodynamics and potential for high gravimetric CO uptakes, MgO-based CO sorbents feature slow carbonation kinetics, limiting their CO uptake during typical industrial contact times.
View Article and Find Full Text PDFAnal Biochem
December 2024
Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Al-Azhar University, 11751, Nasr City, Cairo, Egypt. Electronic address:
Magnesium is an essential mineral in biological systems and has a significant impact on brain health. Its deficiency has been found to correlate with irregular metabolic processes and neurodevelopmental disorders. The objective of this research was to establish and validate an analytical approach based on the standard addition methodology for determining endogenous magnesium levels in the serum of autistic and healthy children.
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