Combining Aryltriazenes and Electrogenerated Acids To Create Well-Defined Aryl-Tethered Films and Patterns on Surfaces

Abstract

Immobilization of submonolayers to 4-5 multilayers of organic molecules on carbon surfaces can be performed by in situ generation of aryl radicals from aryltriazenes. The central idea consists of oxidatively forming an electrogenerated acid of N,N'-diphenylhydrazine to convert the aryltriazene to the corresponding diazonium salt in the diffusion layer of the electrode. In a second step, the diazonium salt is reduced at the same electrode to give a surface of covalently attached aryl groups. In this manner, various moieties tethered to the aryl groups can be immobilized on the surface. Here a ferrocenyl group was introduced as redox marker, the electrochemical signal of which is extraordinarily well-defined. This behavior is independent of film thickness, the latter being easily controlled by the number of repetitive cycles performed. It is also demonstrated that the new approach is suitable for patterning of surfaces using scanning electrochemical microscopy.

Carbon surface derivatization by electrochemical reduction of a diazonium salt in situ produced from the nitro precursor

“…Thus, the ''one pot'' procedure, under optimized conditions, can be approximated to the sum of quantitative steps that mimic well the sequential procedure in a thin solution layer against the electrode surface. Since, this original procedure is promising for the local production of diazonium salts from nitro precursors and allows reconsidering the use of diazonium salts for microelectrochemical patterning of surfaces by application of the scanning electrochemical microscopy [28,[43][44][45].…”

Parallel Imaging and Template‐Free Patterning of Self‐Assembled Monolayers with Soft Linear Microelectrode Arrays

“…[2] Other probe-generated reagents include metal ions for metal deposition, [9,10] catalytically active metal ions, [11] and aryl diazonium salts. [6,12] The pH shift associated with nitrite oxidation was applied in the local etching of a thin Ni coating on a gold substrate in a chemical lens. [13] Kanoufi et al reported the localized reduction of poly(tetrafluoroethylene) [14] and the oxidation of polystyrene [15] followed by further surface treatments.…”

Reactivity of Surfaces Determined by Local Electrochemical Triggering: A Bromo‐Terminated Self‐Assembled Monolayer

“…The amount of unreacted C À Br within a pattern, q CÀBr (Figure 2 f), was attested from their engagement in growth of polymer brushes by ATRP and shown by local ellipsometric measurement (see the Supporting Information). It should be possible to scrutinize a wide range of organic, [16,21,22] organometallic, [23] or inorganic [24] chemical reactions, which is a fundamental issue to assist in the rational selection of conditions for surface or material synthesis. For a linear activation-driving force variation, the C À Br reductive transformation is associated to a transfer coefficient a = RT dln(k etch )/FdE 0 = 0.18, in favor to a large reorganization, as in bond-dissociative ET.…”

“…It is even not restricted to redox reagents owing to the chemical diversity that can be generated by SECM electrochemical activation or by a SICM micropipette delivering system. It should be possible to scrutinize a wide range of organic, [16,21,22] organometallic, [23] or inorganic [24] chemical reactions, which is a fundamental issue to assist in the rational selection of conditions for surface or material synthesis.…”