ChemInform Abstract: Organic Electron Transfer Systems. Part 2. Substituted Triarylamine Cation-Radical Redox Systems - Synthesis, Electrochemical and Spectroscopic Properties, Hammet Behavior, and Suitability as Redox Catalysts.

Redox-active guanidines are ideal proton-coupled electron-transfer (PCET) reagents, since they combine a high Brønsted basicity with a low and tunable redox potential. In this article, the development of redox-active guanidines (especially guanidino-functionalized aromatics, GFAs) in the last ten years is summarized, and their properties compared to other organic Brønsted bases and organic electron donors. First, some applications in organic chemistry that purely use the redox activity (formation of organic donor–acceptor materials and photochemical reductive C–C coupling reactions) are presented. Then, reactions that involve both proton and electron transfer are reviewed. In stoichiometric reactions, redox-active guanidines are used for the dehydrogenative coupling of thiols and phosphanes. The first redox catalytic applications are discussed, using dioxygen as green oxidizing reagent.1 Introduction2 Redox-Active Amines and Guanidines3 Brønsted Basicity of Amines and Guanidines4 Variations of GFA Compounds5 GFA Compounds in Organic Donor–Acceptor Materials and as Reducing Reagents in Organic Synthesis6 Stoichiometric Dehydrogenative Coupling Reactions with Redox-Active Guanidines7 Guanidines as Redox Catalysts8 Conclusions and Outlook

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Evidence for electron transfer in reactions of thianthrene cation radical with dialkylmercurials [Erratum to document cited in CA112(21):198622b]

The Journal of Organic Chemistry ◽

10.1021/jo00304a039 ◽

1990 ◽

Vol 55 (17) ◽

pp. 5180-5180

Author(s):

Stanislaw Lochynski ◽

Henry J. Shine ◽

Miroslaw Soroka ◽

T. Krishnan Venkatachalam

Keyword(s):

Electron Transfer ◽

Cation Radical

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Electrochemical communication between microbial cells and electrodes via osmium redox systems

Biochemical Society Transactions ◽

10.1042/bst20120120 ◽

2012 ◽

Vol 40 (6) ◽

pp. 1330-1335 ◽

Cited By ~ 32

Author(s):

Kamrul Hasan ◽

Sunil A. Patil ◽

Dónal Leech ◽

Cecilia Hägerhäll ◽

Lo Gorton

Keyword(s):

Electron Transfer ◽

Biofuel Cells ◽

Major Group ◽

Electrochemical Biosensors ◽

Bioelectrochemical Systems ◽

Bacterial Cells ◽

Redox Systems ◽

Microbial Cells ◽

Fundamental Part ◽

Micro Organisms

Electrochemical communication between micro-organisms and electrodes is the integral and fundamental part of BESs (bioelectrochemical systems). The immobilization of bacterial cells on the electrode and ensuring efficient electron transfer to the electrode via a mediator are decisive features of mediated electrochemical biosensors. Notably, mediator-based systems are essential to extract electrons from the non-exoelectrogens, a major group of microbes in Nature. The advantage of using polymeric mediators over diffusible mediators led to the design of osmium redox polymers. Their successful use in enzyme-based biosensors and BFCs (biofuel cells) paved the way for exploring their use in microbial BESs. The present mini-review focuses on osmium-bound redox systems used to date in microbial BESs and their role in shuttling electrons from viable microbial cells to electrodes.

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