title: Formation of mixed organic layers by stepwise electrochemical reduction of diazonium compounds.
abstract: This work describes the formation of a mixed organic layer covalently attached to a carbon electrode. The strategy adopted is based on two successive electrochemical reductions of diazonium salts. First, bithiophene phenyl (BTB) diazonium salt is reduced using host/guest complexation in a water/cyclodextrin (β-CD) solution. The resulting layer consists of grafted BTB oligomers and cyclodextrin that can be removed from the surface. The electrochemical response of several outer-sphere redox probes on such BTB/CD electrodes is close to that of a diode, thanks to the easily p-dopable oligo(BTB) moieties. When CD is removed from the surface, pinholes are created and this diode like behavior is lost. Following this, nitrophenyl (NP) diazonium is reduced to graft a second component. Electrochemical study shows that upon grafting NP insulating moieties, the diode-like behavior of the layer is restored which demonstrates that NP is grafted predominately in the empty spaces generated by β-CD desorption. As a result, a mixed BTB/NP organic layer covalently attached to a carbon electrode is obtained using a stepwise electrochemical reduction of two diazonium compounds.
authors.affiliation: Nano-Electro-Chemistry Group, Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, Paris, France.
authors.forename: Luis
authors.initials: L
authors.lastname: Santos
authors.forename: Jalal
authors.initials: J
authors.lastname: Ghilane
authors.forename: Jean Christophe
authors.initials: JC
authors.lastname: Lacroix
mesh_terms: D002244:Carbon / Q000737:chemistry; D003979:Diazonium Compounds / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D010084:Oxidation-Reduction; D013499:Surface Properties; D013876:Thiophenes / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D003979:Diazonium Compounds; D013876:Thiophenes; D047392:beta-Cyclodextrins; D002244:Carbon