Radical grafting of carbon surfaces by oxidation of 5-nitroindole derived anions

González‐Fuentes, Miguel A.; Díaz-Sánchez, Blanca R.; Vela, Alberto; González, Felipe J.

doi:10.1016/j.jelechem.2012.02.012

Cited by 11 publications

(4 citation statements)

References 47 publications

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“…Noted that the deviation obtained with the DBU (see the system V:8 in Figure ) is presumably due to a different mechanism for the oxidation of the p‐bromoaniline in the presence of a very strong base, as it was evoked above. It can also be due to a singular stoichiometry for the complex V:8 , since the equation (2) is only applicable to 1 : 1 hydrogen bonded complexes, or to a deprotonation of the p‐bromoaniline becoming energetically accessible with DBU …”

Section: Electrochemical and Basicity Data In Acetonitrile For The Nimentioning

confidence: 99%

Base‐Assisted Electrografting of Aromatic Amines

et al. 2019

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Contrary to aliphatic amines, aromatic amines have received less attention for surface modification by oxidation due to the low acidity of their cation radicals. To overcome this limitation, bases are often added into the solution to facilitate or to make the grafting possible. However, there has only been a modest focus on their impact on the grafting efficiency. Here, the anodic behavior of a series of para-substituted anilines was investigated in the presence of different bases to address this issue. From complete sets of Brønsted acidity/basicity data and H-bond acidity/basicity factors for both para-substituted anilines and bases, a grafting efficiency index was proposed as a practical tool to choose the most suitable base for the grafting. As a proof-of-concept for base-assisted grafting of aromatic amines, two aniline/base systems were tested to modify carbon surfaces at lower potential, compared to the modification achieved from pure aniline solutions.

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Section: Electrochemical and Basicity Data In Acetonitrile For The Nimentioning

confidence: 99%

Base‐Assisted Electrografting of Aromatic Amines

et al. 2019

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“…The bonding is strong, and in some cases the existence of a covalent bond has been demonstrated by experimental or theoretical methods . Aryl radicals can be obtained by reduction of diazonium salts, oxidation of hydrazines, and carbanions, while alkyl radicals result from the oxidation of carboxylates or carbanions and reduction of alkyl halides . Since the latter compounds are electrochemically reduced at quite negative potentials, it is necessary to reduce C 6 H 13 I at −2.3 V/SCE in acetonitrile (ACN) on an Au electrode to attach the resulting radical to this surface .…”

Section: Introductionmentioning

confidence: 99%

Surface Functionalization of Metals by Alkyl Chains through a Radical Crossover Reaction

et al. 2016

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Alkyl chains are covalently attached onto metal surfaces by indirect reduction of the bromoalkyl derivative (RBr). This indirect reaction involves the formation (by spontaneous or electrochemical reduction of the 2,6-dimethylbenzenediazonium salt) of a sterically hindered aryl radical that abstracts a Br atom from RBr but does not react with the surface. This crossover reaction furnishes an alkyl radical that reacts with the surface. Starting from 6-bromohexanoic acid, carboxylic functionalized gold surfaces are prepared. "Layer-by-layer" assemblies are built from these surfaces and present some ionic selectivity.

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“…The covalent modification of carbon surfaces by electrografting began in the last decade of the past century with the oxidation of primary amines and the reduction of aryldiazonium cations, which allowed the attachment of organic moieties on carbon surfaces through N−C and C−C bonds respectively . After these pioneering studies, a wide variety of alternative electrografting methods have been developed, which involve the generation of free radicals at the electrode‐solution interface, either in reduction or oxidation processes . An advantage of these covalently modified surfaces is the fact that they have high chemical and physical stability and show similar properties to the attached molecules.…”

Section: Introductionmentioning

confidence: 99%

“…[1,2] After these pioneering studies, a wide variety of alternative electrografting methods have been developed, which involve the generation of free radicals at the electrode-solution interface, either in reduction [3][4][5][6][7] or oxidation processes. [8][9][10][11][12] An advantage of these covalently modified surfaces is the fact that they have high chemical and physical stability and show similar properties to the attached molecules. These properties have been considered of relevance for many applications which have been reviewed.…”

Section: Introductionmentioning

confidence: 99%

Effect of Electrolyte Ions on the Formation, Electroactivity, and Rectification Properties of Films Obtained by Electrografting

2019

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The oxidation of 4‐(4‐nitrophenyl)butyrate ions in acetonitrile was used to modify glassy carbon surfaces with films bearing 3‐(4‐nitrophenyl)propyl groups. The main features of the voltammetric reduction of the grafted nitrophenyl groups were studied in two different supporting electrolytes; n‐Bu4NPF6 and Me4NPF6. The best response was obtained with the less bulky electrolyte, which was explained by the major capability of these ions to diffuse inside the channels of the grafted film, as well as the better stabilization of the radical anions generated during the reduction process. It was also shown that the films electrografted in presence of the bulky n‐Bu4NPF6 are thicker but less compact than those prepared in Me4NPF6. The amount of nitrophenyl groups in the grafted film that can be reduced depends on the size of the electrolyte ions. The permeation of the electrolyte ions inside the film channels determines also the voltammetric behavior of ferrocene as redox probe. A current rectification phenomenon was observed in acetonitrile solutions of bulky and hydrophobic electrolytes like n‐Bu4NPF6 and n‐Hx4NPF6, whose marginal inclusion inside the film channels promotes both the entrance of ferrocene and the expelling of ferrocenium ions from these ones. This phenomenon was emulated through a CEC mechanism in solution, where the diffusion inside the channels was described as single chemical equilibria.

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Radical grafting of carbon surfaces by oxidation of 5-nitroindole derived anions

Cited by 11 publications

References 47 publications

Base‐Assisted Electrografting of Aromatic Amines

Base‐Assisted Electrografting of Aromatic Amines

Surface Functionalization of Metals by Alkyl Chains through a Radical Crossover Reaction

Effect of Electrolyte Ions on the Formation, Electroactivity, and Rectification Properties of Films Obtained by Electrografting

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