The catalytic, alcoholytic kinetic resolution of oxazinones is reported. A novel, stereochemically dense cinchona alkaloid-based catalyst can facilitate the highly enantiodiscriminatory (S up to 101) ring-opening of oxazinones equipped with electrophilic aryl units to generate orthogonally protected β-amino acids for the first time.
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http://dx.doi.org/10.1039/d1ob01306h | DOI Listing |
Absolute line strength measurements of hydroperoxyl (HO2) radical in the OO-stretching (ν3) fundamental band have been performed by means of mid-infrared time-resolved dual-comb spectroscopy. By employing two sets of dual-comb spectrometers, high-resolution time-resolved spectra of HO2 and HCl, formed in the photolysis reaction system of Cl2/CH3OH/O2, could be, respectively, measured near 1123 and 3059 cm-1. With kinetic simulations, spectral analysis of both HO2 and HCl, as well as the accurate line strength of the HCl R(9) transition at 3059.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
This work describes the design and implementation of optics for EXCLAIM, the EXperiment for Cryogenic Large-Aperture Intensity Mapping. EXCLAIM is a balloon-borne telescope that will measure integrated line emission from carbon monoxide at redshifts z < 1 and ionized carbon ([CII]) at redshifts z = 2.5 - 3.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Shandong University, Department of Chemistry, 27 South Shanda Road, 250100, Jinan, CHINA.
Planar chirality found tremendous use in many fields, such as chemistry, optics, and materials science. In particular, planar chiral [2.2]paracyclophanes (PCPs) are a type of structurally interesting and practically useful chiral compounds bearing unique electronic and photophysical properties and thus have been widely used in π-stacking polymers, organic luminescent materials, and as a valuable toolbox for developing chiral ligands or organocatalysts.
View Article and Find Full Text PDFChemistry
January 2025
Beijing Normal University, College of Chemistry, Xiejiekou NO.19, 100875, Beijing, CHINA.
Optically pure monosubstituted [n]paracyclophanes are promising candidates for material synthesis, asymmetric catalysis, and drug discovery. Thus far, only a few catalytic asymmetric synthesis processes have been reported for assessing these stained atropisomers. In this study, we describe a highly enantioselective synthesis of monosubstituted [n]paracyclophanes by combining desymmetrization and kinetic resolution.
View Article and Find Full Text PDFSmall Methods
January 2025
Institute of Particle Technology (LFG), Department of Chemical and Biological, Engineering (CBI), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058, Erlangen, Germany.
Knowledge of the structure-property relationships of functional nanomaterials, including, for example, their size- and composition-dependent photoluminescence (PL) and particle-to-particle variations, is crucial for their design and reproducibility. Herein, the Angstrom-resolution capability of an analytical ultracentrifuge combined with an in-line multiwavelength emission detection system (MWE-AUC) for measuring the sedimentation coefficient-resolved spectrally corrected PL spectra of dispersed nanoparticles is demonstrated. The capabilities of this technique are shown for giant-shell CdSe/CdS quantum dots (g-QDs) with a PL quantum yield (PL QY) close to unity capped with oleic acid and oleylamine ligands.
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