Electron Transfer to Sulfides and Disulfides: Intrinsic Barriers and Relationship between Heterogeneous and Homogeneous Electron-Transfer Kinetics

Electron Transfer to Sulfides and Disulfides: Intrinsic Barriers and Relationship between Heterogeneous and Homogeneous Electron-Transfer Kinetics

The electron‐acceptor properties of series of related sulfides and disulfides were investigated in N,N‐dimethylformamide with homogeneous (redox catalysis) and/or heterogeneous (cyclic voltammetry and convolution analysis) electrochemical techniques. The electron‐transfer rate constants were determi...

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Bibliographic Details
Published in:Chemistry : a European journal Vol. 13; no. 28; pp. 7983 - 7995
Main Authors: Meneses, Ana Belèn, Antonello, Sabrina, Arévalo, Maria Carmen, González, Concepcion Carmen, Sharma, Jadab, Wallette, Andrea N., Workentin, Mark S., Maran, Flavio
Format: Journal Article
Language:English
Published: Weinheim WILEY-VCH Verlag 01-01-2007
WILEY‐VCH Verlag
Subjects:
Disulfides - chemistry
electrochemistry
electron transfer
Electron Transport
Kinetics
reduction
substituent effects
Sulfides - chemistry
sulfur
Thermodynamics
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Summary:The electron‐acceptor properties of series of related sulfides and disulfides were investigated in N,N‐dimethylformamide with homogeneous (redox catalysis) and/or heterogeneous (cyclic voltammetry and convolution analysis) electrochemical techniques. The electron‐transfer rate constants were determined as a function of the reaction free energy and the corresponding intrinsic barriers were determined. The dependence of relevant thermodynamic and kinetic parameters on substituents was assessed. The kinetic data were also analyzed in relation to corresponding data pertaining to reduction of diaryl disulfides. All investigated reductions take place by stepwise dissociative electron transfer (DET) which causes cleavage of the CalkylS or SS bond. A generalized picture of how the intrinsic electron‐transfer barrier depends on molecular features, ring substituents, and the presence of spacers between the frangible bond and aromatic groups was established. The reduction mechanism was found to undergo a progressive (and now predictable) transition between common stepwise DET and DET proceeding through formation of loose radical anions. The intrinsic barriers were compared with available results for ET to several classes of dissociative‐ and nondissociative‐type acceptors, and this led to verification that the heterogeneous and the homogeneous data correlate as predicted by the Hush theory. Dissociative reduction of series of sulfides and disulfides was investigated, and a generalized picture of how the intrinsic electron‐transfer barrier depends on various molecular features could be established. The heterogeneous and the homogeneous intrinsic barriers were compared with results for electron transfer to a variety of classes of dissociative‐ and nondissociative‐type acceptors (see picture), and the validity of the Hush model could be verified.
Bibliography:Ministero dell′Istruzione, dell′Università e della Ricerca (MIUR, Italy)
Natural Science and Engineering Research Council (NSERC)
istex:07019B53945CA5C3F06BCBFDB0194E52650A511F
ark:/67375/WNG-3J0KPS5F-9
ArticleID:CHEM200700382
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.200700382