We report on the electron analog of the single-photon gun. On-demand single-electron injection in a quantum conductor was obtained using a quantum dot connected to the conductor via a tunnel barrier. Electron emission was triggered by the application of a potential step that compensated for the dot-charging energy. Depending on the barrier transparency, the quantum emission time ranged from 0.1 to 10 nanoseconds. The single-electron source should prove useful for the use of quantum bits in ballistic conductors. Additionally, periodic sequences of single-electron emission and absorption generate a quantized alternating current.
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http://dx.doi.org/10.1126/science.1141243 | DOI Listing |
J Org Chem
January 2025
Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States.
This report describes the design, development, and optimization of an electrochemical deoxyfluorination of arenes using a tetrafluoropyridine-derived leaving group. NEt·3HF serves as the fluoride source, and the reactions are conducted using either constant potential or constant current electrolysis in an undivided electrochemical cell. Mechanistic studies support a net oxidative pathway, in which initial single-electron oxidation generates a radical cation intermediate that is trapped by fluoride.
View Article and Find Full Text PDFACS Cent Sci
January 2025
Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou 221004, China.
Herein, we report a visible-light-induced charge-transfer-complex-enabled dicarboxylation and deuterocarboxylation of C=C bonds with oxalate as a masked CO source under catalyst-free conditions. In this reaction, we disclosed the first example that the tetrabutylammonium oxalate could be able to aggregate with aryl substrates via π-cation interactions to form the charge transfer complexes, which subsequently triggers the single electron transfer from the oxalic dianion to the ammonium countercation under irradiation of 450 nm bule LEDs, releasing CO and CO radical anions. Diverse alkenes, dienes, trienes, and indoles, including challenging trisubstituted olefins, underwent dicarboxylation and anti-Markovnikov deuterocarboxylation with high selectivity to access valuable 1,2- and 1,4-dicarboxylic acids as well as indoline-derived diacids and β-deuterocarboxylic acids under mild conditions.
View Article and Find Full Text PDFOrg Lett
January 2025
Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, Liaoning, People's Republic of China.
A straightforward and efficient nickel-catalyzed cyclization/carbonylation transformation of -allylbromoacetamides toward the synthesis of 2-pyrrolidinone derivatives has been developed with arylboronic acids as the reaction partner. This transformation proceeds through a sequential single-electron-transfer pathway via 5-- cyclization and carbonyl insertion steps, furnishing a variety of 2-pyrrolidinone derivatives in good yields. Various useful functional groups were well tolerated.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Henan Key Laboratory of Natural Medicine Innovation and Transformation, Henan University, Kaifeng, Henan 475004, PR China.
Recent advancements in green and sustainable platforms, particularly visible light-driven photocatalysis, have spurred significant progress in radical chemistry, enabling the efficient synthesis of important molecules from simple and readily available feedstocks under mild conditions. However, the rapid orbital flipping and high reactivity of radicals pose substantial challenges for achieving precise enantiocontrol in stereocenter formation via radical coupling. In this study, we present a generic and efficient strategy that modulates this elusive approach, facilitating enantiocontrollable protonation through 1,3-boron migration.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Yunnan University, Key Laboratory of Medicinal Chemistry for Natural Resources, Ministry of Education, East Outer Ring Road, 650500, Kunming, CHINA.
The reduction of carboxylic esters to aldehydes and alcohols is a fundamental functional group transformation in chemistry. However, the inertness of carbonyl group and the instability of ketyl radical anion intermediate impede the reduction of carboxylic esters via photochemical strategy. Herein, we described the reduction of aliphatic carboxylic esters with synergistic dual photocatalysis via phenolate-catalyzed single electron transfer process and thiol-catalyzed hydrogen atom transfer process.
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