Locally Induced and Self-Induced “Electroclick” onto a Self-Assembled Monolayer: Writing and Reading with SECM under Unbiased Conditions

Abstract

Localized "electroclick" was achieved on azido-terminated self-assembled monolayers using Scanning Electrochemical Microscopy (SECM) in feedback mode, in which the substrate is not electrically connected (unbiased conditions). The method allows both the local immobilization of diverse functional moieties and the monitoring of each modification step at a micrometer scale. Conditions of the "click" coupling reaction were optimized especially to avoid the deposit of metallic copper by the choice of a specific ligand to stabilize the Cu(I) species. The catalytic efficiency in localized "electroclick" reaction of Cu(II)TMPA (TMPA: tris(2-pyridylmethyl)amine) as the "click" catalyst was compared with a derivative containing an alkyne group Cu(II)6eTMPA, the same molecule playing the role of the catalyst and the substrate. Evidences for surface self-catalysis propagation are demonstrated through SECM imaging showing a random 2D progression of the catalytic modification.

Electrochemical nanoarchitectonics and layer-by-layer assembly: From basics to future

“…Local generation and propagation of Cu(I) catalytic ions can be triggered by (a) microelectrodes [330], (b) local probes [380,381], (c) electrogenerated gradients [383,384], and (d) bipolar electrochemistry [382]. [381,387,388] Azido-silane monolayer Electro-generated gradients 50 Biomaterials, cellular migration control [383,384,389] PEDOT-N 3 Bipolar electro-chemistry Unknown Energetic devices, Biomaterials [382] resolution. For instance, by using 25 and 12.5 m diameter UMEs at a distance of 10 m from the surface, Quinton et al could improve the resolution to 75 m [387].…”

“…In that work, an azido-aryl monolayer was patterned by electroclick with ethynylferrocene, allowing spatially resolved electrocatalysis of potassium ferrocyanide. Recently, reducing the UME diameter and the distance to the substrate to 5 m allowed 20 m resolution to be obtained [388]. When self-induced electroclick was performed on azido-terminal SAMs, immobilization of Cu(I) complexes resulted in an auto-catalytic propagation of the functionalization area, decreasing the final resolution (Table 5).…”

Localized Electrochemistry for Studying Functional Carbon Surfaces

“…A first situation concerns a common and simplest system: a non‐electroactive layer is deposited onto a conducting surface. As an example, we consider a metallic electrode covered by a thiol‐alkane layer forming a self‐assembled monolayer (SAM) and terminated by azide moieties . This monolayer could be modified by a post‐functionalization using the classical click chemistry coupling using an alkyne derivative .…”

“…The method permits the monitoring of the post‐functionalization and is usable even if the attached moieties are not electroactive. Similar methods could be developed for sensors in analytical applications for characterizing the attachment of a bulky molecule .…”

Electroassisted click chemistry immobilisation of gold nanoparticles on a solid substrate

“…Electrochemical catalyst generation offers better control over the process time as compared to chemical formation of Cu(I). There are several reports on performing click chemistry on a surface by electrochemical generation of Cu(I) catalyst [14][15][16][17]. However, the "electro-click" method has not been used previously for immobilisation of nanoparticles on solid surfaces.…”