Electrochemical and STM Studies of 1-Thio-β-d-glucose Self-Assembled on a Au(111) Electrode Surface

In this study, a Au(111) electrode is functionalized with a monolayer of 1-thio-β-d-glucose (β-Tg), producing a hydrophilic surface. A monolayer of β-Tg was formed on a Au(111) surface by either (1) potential-assisted deposition with the thiol in a supporting electrolyte or (2) passive incubation of...

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Bibliographic Details
Published in:Langmuir 2011-11, Vol.27 (21), p.13383-13389
Main Authors: Kycia, Annia H, Sek, Slawomir, Su, Zhangfei, Merrill, A. Rod, Lipkowski, Jacek
Format: Article
Language:English
Subjects:
Chemistry
Electric Capacitance
Electrochemistry
Electrochemistry - methods
Electrochemistry: Charge Transfer, Electrocatalysis, Kinetics, Bioelectrochemistry
Electrodes
Electrolytes - chemistry
Exact sciences and technology
General and physical chemistry
Glucose - analogs & derivatives
Glucose - chemistry
Gold - chemistry
Microscopy, Scanning Tunneling
Models, Molecular
Molecular Conformation
Surface Properties
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Summary:In this study, a Au(111) electrode is functionalized with a monolayer of 1-thio-β-d-glucose (β-Tg), producing a hydrophilic surface. A monolayer of β-Tg was formed on a Au(111) surface by either (1) potential-assisted deposition with the thiol in a supporting electrolyte or (2) passive incubation of a gold substrate in a thiol-containing solution. For each method, the properties of the β-Tg monolayer were investigated using cyclic voltammetry (CV), differential capacitance (DC), and chronocoulometry. In addition, electrochemical scanning tunneling microscopy (EC-STM) was used to obtain images of the self-assembled monolayer with molecular resolution. Potential-assisted assembly of β-Tg onto a Au(111) electrode surface was found to be complicated by oxidation of β-Tg molecules. The EC-STM images revealed formation of a passive layer containing honeycomb-like domains characteristic of a formation of S8 rings, indicating the S–C bond may have been cleaved. In contrast, passive self-assembly of thioglucose from a methanol solution was found to produce a stable, disordered monolayer of β-Tg. Since the passive assembly method was not complicated by the presence of a faradaic process, it is the method of choice for modifying the gold surface with a hydrophilic monolayer.
ISSN:0743-7463
1520-5827
DOI:10.1021/la202978d