COLL 204

We have determined the structures of self-assembled monolayers (SAMs) of 2-adamantanethiol on Au{111} using scanning tunneling microscopy (STM). These SAMs of 2-adamantanethiol on Au{111} have different structures and rotational domains than 1-adamantanethiol SAMs. There are two dominant domain structures that show different labilities in the presence of dilute n-alkanethiol solutions. The alternating linear structure shows resistance to displacement by alkanethiols, while disordered regions exhibit rapid displacement. Stronger van der Waals interactions between 2-adamantanethiol molecules relative to 1-adamantanethiols result in a striped phase of long-chain alkanethiols after displacement. Co-adsorbed SAMs of 1-adamantanethiol and 2-adamantanethiol on Au{111} enable further control and selection of displacement.