Use of Selective Redox Cross-Inhibitors for the Control of Organic Layer Formation Obtained via Diazonium Salt Reduction

The controlled electrochemical deposition of a series of four diazonium salts (4-bromobenzene, 4-iodobenzene, 4-methoxybenzene, and 4-diethylaminobenzene diazonium) on carbon surfaces has been achieved by exploiting the use of three redox mediators: 2,2-diphenyl-1-picrylhydrazyl, chloranil, and dich...

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Bibliographic Details
Published in:Langmuir 2019-08, Vol.35 (34), p.11048-11055
Main Authors: López, Isidoro, Dabos-Seignon, Sylvie, Breton, Tony
Format: Article
Language:English
Subjects:
Chemical Sciences
Material chemistry
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Summary:The controlled electrochemical deposition of a series of four diazonium salts (4-bromobenzene, 4-iodobenzene, 4-methoxybenzene, and 4-diethylaminobenzene diazonium) on carbon surfaces has been achieved by exploiting the use of three redox mediators: 2,2-diphenyl-1-picrylhydrazyl, chloranil, and dichlone. The efficiency of the method rests on a fast redox cross-reaction in the diffusion layer between the diazonium compound and the reduced form of the selected inhibitor, characterized by an outer-sphere electron transfer. The effect of the inhibitor addition in the deposition solution was characterized using electrochemical techniques, X-ray photoelectron spectroscopy, and atomic force microscopy. Near-monolayers are obtained when the potential of the redox mediator is at least 100 mV lower than the reduction potential of the diazonium salt concerned. A judicious choice of the redox entity can allow, via a fine control of the experimental conditions, to modulate the thickness of organic layers by varying the grafting potential.
ISSN:0743-7463
1520-5827
DOI:10.1021/acs.langmuir.9b01397