Electrochemical and STM studies of 1-thio-β-D-glucose self-assembled on a Au(111) electrode surface

Langmuir. 2011 Nov 1;27(21):13383-9. doi: 10.1021/la202978d. Epub 2011 Oct 11.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electric Capacitance
  • Electrochemistry / methods*
  • Electrodes
  • Electrolytes / chemistry
  • Glucose / analogs & derivatives*
  • Glucose / chemistry
  • Gold / chemistry*
  • Microscopy, Scanning Tunneling*
  • Models, Molecular
  • Molecular Conformation
  • Surface Properties

Substances

  • Electrolytes
  • Gold
  • 1-thioglucose
  • Glucose