Dithiocarbamates: Functional and Versatile Linkers for the Formation of Self-Assembled Monolayers

Abstract

Self-assembled monolayers have evolved into one of the best established self-assembly systems with high relevance in a scientific and applied context. So far, however, virtually exclusively thiol functional groups have been used for the investigation of fundamental processes on metal surfaces. In this paper, an alternative binding group, the dithiocarbamate (DTC) group, is re-visited. Complete SAM formation with new layer properties characteristically different from thiol SAMs is demonstrated for mono-functional acyclic and bifunctional cyclic dithiocarbamates on Au111 by X-ray photoelectron spectroscopy, cyclic voltammetry, and scanning tunneling microscopy. Furthermore, the chemical adsorption and voltammetric desorption reactions are quantitatively determined. The resonant bi-dentate structure of the DTC provides a characteristically different molecule-metal coupling compared to the thiols and makes the DTC an interesting system for molecular electronics.