Details

Autor(en) / Beteiligte

• Collman, James P
• Devaraj, Neal K
• Eberspacher, Todd P. A
• Chidsey, Christopher E. D

Titel

Mixed Azide-Terminated Monolayers:  A Platform for Modifying Electrode Surfaces

Ist Teil von

• Langmuir, 2006-03, Vol.22 (6), p.2457-2464

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2006

Quelle

MEDLINE

Beschreibungen/Notizen

• We have prepared and characterized mixed self-assembled monolayers (SAM) on gold electrodes from azido alkane thiols and various ω-functionalized alkane thiols. In the presence of copper(I) catalysts, these azide-modified surfaces are shown to react rapidly and quantitatively with terminal acetylenes forming 1,2,3-triazoles, via “click” chemistry. The initial azide substituents can be identified and monitored using both grazing-angle infrared (IR) and X-ray photoelectron spectrosopies. Acetylenes possessing redox-active ferrocene substituents react with the azide-terminated mixed SAMs and electrochemical measurements of the ferrocene-modified SAM electrodes have been used to quantify the redox centers attached to these platforms. Time-resolved electrochemical measurements have enabled us to follow the formation of these ferrocene centers and thus to measure the rate of the surface “click” reaction. Under optimal conditions this well-behaved second-order reaction takes place with a rate constant of 1 × 103 M-1 s-1. Typical reaction times of several minutes were realized using micromolar concentrations of acetylene. These techniques have been used to construct well-characterized, covalently modified monolayers that can be employed as functional electrode surfaces.