Give me a tip: In situ production of diazonium salts from nitro compounds allows the use of diazonium chemistry for microelectrochemical patterning of surfaces by scanning electrochemical microscopy. The nitro precursor is reduced at the tip to the amine, which is diazotized in the interelectrode space as it diffuses (see picture). The tip acts as a source of diazonium salts, allowing sample derivatization just beneath the tip.
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http://dx.doi.org/10.1002/anie.200900498 | DOI Listing |
Molecular junctions (MJs) are celebrated nanoelectronic devices for mimicking conventional electronic functions, including rectifiers, sensors, wires, switches, transistors, negative differential resistance, and memory, following an understanding of charge transport mechanisms. However, capacitive nanoscale molecular junctions are rarely seen. The present work describes electrochemically (E-Chem) grown covalently attached molecular thin films of 10, 14.
View Article and Find Full Text PDFBioelectrochemistry
January 2025
Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, National University of Science and Technology Politehnica Bucharest, 1-7 Gheorghe Polizu St., 011061 Bucharest, Romania. Electronic address:
Herein, we present an efficient approach for developing electrochemical aptasensing interfaces, by "click" postfunctionalization of phenylethynyl-grafted glassy carbon substrates with mixed monolayers containing biorecognition elements and phosphorylcholine zwitterionic groups. Typically, controlling the composition of multicomponent surface layers by grafting from a mixture of aryldiazonium salts is challenging due to differences in their chemical reactivity. Our approach circumvents this issue by employing the electrochemical reduction of a single aryldiazonium salt containing a silyl-protected alkyne group followed by deprotection, to create phenylethynyl monolayers which can subsequently accommodate the concurrent immobilization of bioreceptors and zwitterionic groups through "click" postfunctionalization.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Organic Chemistry, Institute of Chemistry, Federal Fluminense University─UFF, Niteroi, Rio de Janeiro 24020-141, Brazil.
Herein, we report a direct diazenylation of active methylene compounds that is environmentally friendly, cost-effective, and scalable, utilizing a heterogeneous TiO catalyst that is both accessible and recyclable. The scope of this transformation shows excellent compatibility with both electron-rich and electron-poor diazonium salts, yielding the desired products in very good yields at room temperature.
View Article and Find Full Text PDFJ Org Chem
December 2024
Universitaet Potsdam, Institut fuer Chemie, Karl-Liebknecht-Straße 24-25, D-14476 Potsdam-Golm, Germany.
The synthesis of coumarin- and flavonoid-chalcone hybrids via Pd-catalyzed Heck-type coupling of arene diazonium salts and 8-allylcoumarins and -flavonoids is reported. The β-hydride elimination step proceeds with high regioselectivity if an OMOM-substituent is present at the position C7, adjacent to the allyl group. A selective allylic oxidation of the coupling products was accomplished using DDQ in the presence of silica to furnish the chalcones.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Institute of Organic Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
While aromatic diazonium salts are important reagents in organic synthesis, 'Diazonium ions generated from ordinary aliphatic primary amines are usually useless for preparative purposes, since they lead to a mixture of products giving not only substitution by any nucleophile present, but also elimination and rearrangements if the substrate permits.' In this work, we report that this statement is no longer valid, and it is now possible to control diazotization of aliphatic amines by utilizing isopentyl nitrite in HFIP. This transformation enabled electrophilic aromatic substitution with these highly abundant and commercially available alkyl reagents, as well as transforming them into building blocks typically employed in organic synthesis.
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