Long-range Ordered Self-assembled Monolayers of Thioacetyl-protected Tolanes on Au(111) in Catalytic Tetrabutylammonium Cyanide Solution

Abstract

Surface structure and adsorption conditions of tolanethioacetate (TTA) self-assembled monolayers (SAMs) on Au(111) in catalytic tetrabutylammonium cyanide (TBACN) solution were examined by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). We found that SAM formation by adsorption of TTA molecules on Au(111) strongly depends on experimental conditions for the deprotection of thioacetate group. Molecular-scale STM imaging revealed that TTA molecules on Au(111) can form well-ordered SAMs in TBACN catalytic medium in comparison to in pure solvent medium. In addition, XPS measurements showed a strong S 2p peak at 162 eV for TTA SAMs on Au(111), implying that the SAMs were formed via chemical reactions between the sulfur atoms and gold surfaces.