Supramolecular Structures and Chirality in Dithiocarbamate Self-Assembled Monolayers on Au(111)

We report the observation of supramolecular structures in a self-assembled monolayer (SAM) of diethyldithiocarbamate (DEDTC) on the Au(111) substrate. While all sulfur atoms are found to be covalently anchored to the gold substrate for both DEDTC and DT (decanethiol) monolayers, the self-assembly behavior of DEDTC has been observed to be distinctively different from that of DT. We have found hexagonally arranged trimeric domains of DEDTC molecules in two 30° rotated domains, which we assign to a pattern of chiral trimeric domains. The trimers belong to the C₃ point group, and the supramolecular assembly shows a (2√3 × 2√3)R15° surface structure.