ResearchPad - redox-chemistry https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Element–Element Bond Formation upon Oxidation and Reduction]]> https://www.researchpad.co/article/elastic_article_8328 Unexpected E−E bond formation: The versatile redox chemistry of the polypnictogen cobalt complexes [(Cp′′′Co)2(E2)2] (E=P, As) was investigated. Both oxidation and reduction lead to the formation of two new E−E bonds and to the cyclization of the separated E2 ligands into E4 ligands in the coordination sphere of two {Cp′′′Co} fragments.

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<![CDATA[An Air‐Stable, Neutral Phenothiazinyl Radical with Substantial Radical Stabilization Energy]]> https://www.researchpad.co/article/Nb26a93e7-8ff9-4f01-8c80-f3942c9b42e5

Abstract

The vital effect of radical states on the pharmacological activity of phenothiazine‐based drugs has long been speculated. Whereas cationic radicals of N‐substituted phenothiazines show high stability, the respective neutral radicals of N‐unsubstituted phenothiazines have never been isolated. Herein, the 1,9‐diamino‐3,7‐di‐tert‐butyl‐N 1,N 9‐bis(2,6‐diisopropylphenyl)‐10H‐phenothiazin‐10‐yl radical (SQH2 .) is described as the first air‐stable, neutral phenothiazinyl free radical. The crystalline dark‐blue species is characterized by means of EPR and UV/Vis/near‐IR spectroscopy, as well as cyclic voltammetry, spectro‐electrochemical analysis, single‐crystal XRD, and computational studies. The SQH2 . radical stands out from other aminyl radicals by an impressive radical stabilization energy and its parent amine has one of the weakest N−H bond dissociation energies ever determined. In addition to serving as open‐shell reference in medicinal chemistry, its tridentate binding pocket or hydrogen‐bond‐donor ability might enable manifold uses as a redox‐active ligand or proton‐coupled electron‐transfer reagent.

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