How Hydrogen Bonds Affect Reactivity and Intervalence Charge Transfer in Ferrocenium-Phenolate Radicals
- Publikationstyp:
- Zeitschriftenaufsatz
- Metadaten:
-
- Autoren
- Andreas Neidlinger
- Christoph Foerster
- Katja Heinze
- Autoren-URL
- https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=fis-test-1&SrcAuth=WosAPI&KeyUT=WOS:000372657700017&DestLinkType=FullRecord&DestApp=WOS_CPL
- DOI
- 10.1002/ejic.201501471
- eISSN
- 1099-0682
- Externe Identifier
- Clarivate Analytics Document Solution ID: DH2ZZ
- ISSN
- 1434-1948
- Ausgabe der Veröffentlichung
- 8
- Zeitschrift
- EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
- Schlüsselwörter
- Hydrogen bonds
- Charge transfer
- Radicals
- EPR spectroscopy
- Sandwich complexes
- Valence isomers
- Paginierung
- 1274 - 1286
- Datum der Veröffentlichung
- 2016
- Status
- Published
- Titel
- How Hydrogen Bonds Affect Reactivity and Intervalence Charge Transfer in Ferrocenium-Phenolate Radicals
- Sub types
- Article
Datenquelle: Web of Science (Lite)
- Andere Metadatenquellen:
-
- Abstract
- <jats:title>Abstract</jats:title><jats:p>The ferrocenyl‐phenol 2,4‐di‐<jats:italic>tert</jats:italic>‐butyl‐6‐(ferrocenylcarbamoyl)phenol (<jats:bold>H‐1</jats:bold>) forms intramolecular hydrogen bonds which are absent in its constitutional isomer 2,6‐di‐<jats:italic>tert</jats:italic>‐butyl‐4‐(ferrocenylcarbamoyl)phenol (<jats:bold>H‐2</jats:bold>). Their corresponding bases <jats:bold>1</jats:bold><jats:sup>– </jats:sup>and <jats:bold>2</jats:bold><jats:sup>– </jats:sup>show intra‐ and intermolecular NH<jats:bold>···</jats:bold>O hydrogen bonds, respectively. The phenolate <jats:bold>1</jats:bold><jats:sup>–</jats:sup> is reversibly oxidized to <jats:bold>1<jats:sup>·</jats:sup></jats:bold>, whereas <jats:bold>2<jats:sup>–</jats:sup></jats:bold> only undergoes a quasi‐reversible oxidation to <jats:bold>2<jats:sup>·</jats:sup></jats:bold>, which suggests a higher reactivity. The radical pools of <jats:bold>1<jats:sup>·</jats:sup></jats:bold> and <jats:bold>2<jats:sup>·</jats:sup></jats:bold> formed by the oxidation/deprotonation of <jats:bold>H‐1</jats:bold> and <jats:bold>H‐2</jats:bold> have been probed by (rapid‐freeze) electron paramagnetic resonance (EPR) spectroscopy and by spin‐trapping techniques to elucidate the types of radicals present. Ferrocenium phenolate [<jats:bold>1a</jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> featuring an NH<jats:bold>···</jats:bold>O intramolecular hydrogen bond is the most stable radical and undergoes thermal and photoinduced valence isomerization to the phenoxyl radical valence isomer [<jats:bold>1b</jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> with participation of the NH stretching mode (proton‐coupled electron transfer). A ferrocenium iminolate radical [<jats:bold>1c</jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> is present as well and equilibrates with the carbon‐centered ferrocenyl radicals [<jats:bold>1<jats:sup>Cp</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> and [<jats:bold>1</jats:bold><jats:bold><jats:sup>β</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup>. The latter radicals are intercepted by nitrobenzene to give the corresponding stable nitroxyl radicals [<jats:bold>6<jats:sup>Cp</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> and [<jats:bold>6</jats:bold><jats:bold><jats:sup>β</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup>. All the radicals <jats:bold>2<jats:sup>·</jats:sup></jats:bold>, which lack intramolecular hydrogen bonds, are transient in nature due to rapid follow‐up reactions. However, rapid‐freeze EPR spectroscopy indicated the presence of ferrocenium iminolate [<jats:bold>2c</jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup>, the phenoxyl radical [<jats:bold>2b</jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup>, and/or carbon‐centered radicals [<jats:bold>2<jats:sup>Cp</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> and [<jats:bold>2</jats:bold><jats:bold><jats:sup>β</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup>. The carbon‐centered radicals [<jats:bold>2<jats:sup>Cp</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> and [<jats:bold>2</jats:bold><jats:bold><jats:sup>β</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> are selectively trapped as the corresponding nitroxide radicals [<jats:bold>7<jats:sup>Cp</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup> and [<jats:bold>7</jats:bold><jats:bold><jats:sup>β</jats:sup></jats:bold>]<jats:sup><jats:bold>·</jats:bold></jats:sup>. These diverse reactivity patterns are relevant for cytostatic ferrocenyl‐phenols such as ferrocifen.</jats:p>
- Autoren
- Andreas Neidlinger
- Christoph Förster
- Katja Heinze
- DOI
- 10.1002/ejic.201501471
- eISSN
- 1099-0682
- ISSN
- 1434-1948
- Ausgabe der Veröffentlichung
- 8
- Zeitschrift
- European Journal of Inorganic Chemistry
- Sprache
- en
- Online publication date
- 2016
- Paginierung
- 1274 - 1286
- Datum der Veröffentlichung
- 2016
- Status
- Published
- Herausgeber
- Wiley
- Herausgeber URL
- http://dx.doi.org/10.1002/ejic.201501471
- Datum der Datenerfassung
- 2023
- Titel
- How Hydrogen Bonds Affect Reactivity and Intervalence Charge Transfer in Ferrocenium‐Phenolate Radicals
- Ausgabe der Zeitschrift
- 2016
Datenquelle: Crossref
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