The kinetics and mechanism of the reaction between amidogen radical and hydroxyl radical have been theoretically investigated on the lowest singlet and triplet surfaces. The singlet surface consists of two long-lived chemically activated NH(2)OH* and NH(3)O* intermediates with 10 different channels. A hydrogen abstraction channel on the triplet surface proceeds through van der Waals complex in both reactant side and product side to produce NH(3) + O((3)P). The effect of multiple reflections of the van der Waals complexes on the rate constant is investigated. Multichannel RRKM-TST calculations have been carried out to calculate the individual rate constants for the formation of those products that proceed through activated adducts on the singlet surface. The rate constants for direct hydrogen abstraction reactions were calculated by using direct-dynamics canonical variational transition-state theory with small curvature approximation for tunneling.
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http://dx.doi.org/10.1021/jp905197h | DOI Listing |
Redox Biochem Chem
December 2024
Department of Biophysics, Medical College of Wisconsin, Milwaukee, United States.
Peroxynitrite (ONOO/ONOOH) is a short-lived but highly reactive species that is formed in the diffusion-controlled reaction between nitric oxide and the superoxide radical anion. It can oxidize certain biomolecules and has been considered as a key cellular oxidant formed under various pathophysiological conditions. It is crucial to selectively detect and quantify ONOO to determine its role in biological processes.
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January 2025
Institute of Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg, 1, 8093 Zurich, Switzerland.
Buchwald-Hartwig (BH) aminations are crucial for synthesizing arylamine motifs in numerous bioactive molecules and fine chemicals. While homogeneous palladium complexes can be effective catalysts, their high costs and environmental impact motivate the search for alternative approaches. Heterogeneous palladium single-atom catalysts (SAC) offer promising recoverable alternatives in C-C cross-couplings.
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January 2025
Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London W12 0BZ, U.K.
Aryl aldehydes are key synthetic intermediates in the manufacturing of active pharmaceutical ingredients. They are generated on scale (>1000 kg) through the palladium-catalyzed formylation of aryl bromides using syngas (CO/H). The best-in-class catalyst system for this reaction employs di-1-adamantyl--butylphosphine (cataium A), palladium(II) acetate, and tetramethylethylenediamine.
View Article and Find Full Text PDFSmall
January 2025
Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, P. R. China.
Gold (Au) nanoclustersare promising photocatalysts for biomedicine, sensing, and environmental remediation. However, the short carrier lifetime, inherent instability, and unclear charge transfer mechanism hinder their application. Herein, the Au nanoclusters decorated with three different isomers of o-Aminophenol, m-Aminophenol, and p-Aminophenol are synthesized, namely o-Au, m-Au, and p-Au, which achieve efficient hydrogen peroxide (HO) photoproduction through two-step one-electron oxygen reduction reaction (ORR).
View Article and Find Full Text PDFLuminescence
January 2025
Vlokh Institute of Physical Optics, Ivan Franko National University of Lviv, Lviv, Ukraine.
Spectroscopic properties of Tb-doped and Tb-Ag codoped lithium tetraborate (LTB) glasses with LiBO (or LiO-2BO) composition are investigated and analysed using electron paramagnetic resonance (EPR), optical absorption, photoluminescence (PL) and photoluminescence excitation (PLE) spectra, PL decay kinetics and absolute quantum yield (QY) measurements. PL spectra of the investigated glasses show numerous narrow emission bands corresponding to the D → F (J = 6-0) and D → F (J = 5-3) transitions of Tb (4f) ions. The most intense PL band of Tb ions at 541 nm (D → F transition) is characterised by a lifetime slightly exceeding 2.
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