title: Electrochemical and STM studies of 1-thio-β-D-glucose self-assembled on a Au(111) electrode surface.
abstract: 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 S(8) 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.
authors.affiliation: Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
authors.forename: Annia H
authors.initials: AH
authors.lastname: Kycia
authors.forename: Slawomir
authors.initials: S
authors.lastname: Sek
authors.forename: Zhangfei
authors.initials: Z
authors.lastname: Su
authors.forename: A Rod
authors.initials: AR
authors.lastname: Merrill
authors.forename: Jacek
authors.initials: J
authors.lastname: Lipkowski
mesh_terms: D025802:Electric Capacitance; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D005947:Glucose / Q000031:analogs & derivatives* / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D008958:Models, Molecular; D008968:Molecular Conformation; D013499:Surface Properties
chemical_list: D004573:Electrolytes; D006046:Gold; C018399:1-thioglucose; D005947:Glucose