Dithiocarbamate-Based Self-Assembled Monolayers – The Preparation Method Has a Crucial Impact on Structure and Stability

Dithiocarbamates (DTCs) are a promising group of molecules where a bidentate bonding group is used to functionalize metallic surfaces as self-assembled monolayers (SAMs). So far, two methods of DTC SAMs deposition have been employed interchangeably: <i>in situ</i> generation of a DTC compound or synthesis of a <i>salt</i> precursor that can then be used on demand. Here, using the two model DTC SAMs based on phenylpiperidine and phenylpiperazine, we compare for the first time these two synthetic approaches in one study. We show that for the crucial parameters of monolayers, such as packing density and thermal stability, there is a significant difference between the two formation methods, promoting the <i>in situ</i> one, which produces monolayers with high thermal stability (desorption energy ∼ 1.5 eV) and packing densities comparable to that of alkanethiols. On the other hand, we demonstrated overall diminished chemical stability of DTCs compared to alkanethiols, which can be slightly improved using the <i>in situ</i> approach.