ELECTROCHEMICAL REDUCTION OF CYCLIC AND ACYCLIC BENZYL DISULFIDES

In this study, electron transfer (ET) to a series of cyclic and acyclic benzyl disulfides, compounds containing an S-S bond, were studied in N,N-dimethylformamide using the heterogeneous electrochemical techniques of cyclic voltammetry and coulometry. The cyclic disulfides were substituted 2,3- benzodithiin molecules and the acyclic series were bibenzyl disulfides, having the général formula of (X-C6H4-CH2-S-)2. The acyclic series were synthesized as a more suitable model for the cyclic compounds, than those of the established diaryl disulfides. The ET reduction is dissociative (DET), leading to the cleavage of the S-S bond. For the -CN and -NO2 substituted cases, the DET is clearly stepwise with the ET initially to a π* orbital followed by a subsequent thermal ET to the σ* largely associated with the S-S bond. For the other substituents, ET appears to be to the σ* orbital and becomes more concerted, like for the strongly donating substituents. The reduction of both the acyclic and cyclic disulfides occurs at a potential which is considerably greater than that observed for the para-substituted diaryl disulfides. The results from the acyclic series indicate that upon ET, the molecules fragment to give intermediates that react with the starting disulfide. The ramification, mode of fragmentation and mechanistic insights are discussed.

Name thesis:degree_name

M Sc

Discipline thesis:degree_discipline

Chemistry

Year dc:date.issued

2006

Author dc:creator

• Wallette, Andrea N.

Advisor dc:contributor.advisor

• Workentin,

• dissociative electron transfer
• disulfide
• distonic radical anion
• stepwise
• fragmentation
• cyclic voltammetry

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/20400

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/20400