title: One-step formation of bifunctionnal aryl/alkyl grafted films on conducting surfaces by the reduction of diazonium salts in the presence of alkyl iodides.
abstract: The formation of partial perfluoroalkyl or alkyl radicals from partial perfluoroalkyl or alkyl iodides (ICH2CH2C6F13 and IC6H13) and their reaction with surfaces takes place at low driving force (∼-0.5 V/SCE) when the electrochemical reaction is performed in acetonitrile in the presence of diazonium salts (ArN2(+)), at a potential where the latter is reduced. By comparison to the direct grafting of ICH2CH2C6F13, this corresponds to a gain of ∼2.1 V in the case of 4-nitrobenzenediazonium. Such electrochemical reaction permits the modification of gold surfaces (and also carbon, iron, and copper) with mixed aryl-alkyl groups (Ar = 3-CH3-C6H4, 4-NO2-C6H4, and 4-Br-C6H4, R = C6H13 or (CH2)2-C6F13). These strongly bonded mixed layers are characterized by IRRAS, XPS, ToF-SIMS, ellipsometry, water contact angles, and cyclic voltammetry. The relative proportions of grafted aryl and alkyl groups can be varied along with the relative concentrations of diazonium and iodide components in the grafting solution. The formation of the films is assigned to the reaction of aryl and alkyl radicals on the surface and on the first grafted layer. The former is obtained from the electrochemical reduction of the diazonium salt; the latter results from the abstraction of an iodine atom by the aryl radical. The mechanism involved in the growth of the film provides an example of complex surface radical chemistry.
authors.affiliation: †Sorbonne Paris Cité, Univ Paris Diderot, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75013 Paris, France.|‡Chemistry Department of Natural Sciences Faculty, University of Prishtina, rr. "Nëna Tereze" nr. 5, 10000 Prishtina, Kosovo.
authors.forename: Dardan
authors.initials: D
authors.lastname: Hetemi
authors.affiliation: §ESPCI ParisTech, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: Hassan
authors.initials: H
authors.lastname: Hazimeh
authors.affiliation: †Sorbonne Paris Cité, Univ Paris Diderot, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75013 Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Decorse
authors.affiliation: ∥Institut de Recherche de Chimie Paris, UMR 8247 CNRS, 11 rue Pierre et Marie Curie, 75005 Paris, France.
authors.forename: Anouk
authors.initials: A
authors.lastname: Galtayries
authors.affiliation: †Sorbonne Paris Cité, Univ Paris Diderot, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75013 Paris, France.|§ESPCI ParisTech, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Combellas
authors.affiliation: †Sorbonne Paris Cité, Univ Paris Diderot, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75013 Paris, France.|§ESPCI ParisTech, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Kanoufi
authors.affiliation: †Sorbonne Paris Cité, Univ Paris Diderot, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75013 Paris, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Pinson
authors.affiliation: †Sorbonne Paris Cité, Univ Paris Diderot, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75013 Paris, France.|‡Chemistry Department of Natural Sciences Faculty, University of Prishtina, rr. "Nëna Tereze" nr. 5, 10000 Prishtina, Kosovo.|§ESPCI ParisTech, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: Fetah I
authors.initials: FI
authors.lastname: Podvorica