Functionalized self-assembled alkanethiol monolayers on Au(111) electrodes: 1. Surface structure and electrochemistry

Functionalized alkanethiols (-CH3, -NH2, -OH, -COOH, -SH, -SO3H, -CN) of di fferent lengths, self-assembled on Au(111), were studied with cyclic voltam metry and in situ scanning tunneling microscopy. The surface structure was determined under potential conditions at which only a dielectric behavior i s expected. In general, the size of the terminal group together with the ch emical interaction between neighboring thiol molecules plays a crucial role for the resulting adlayer structure. Shorter-chain thiols with bulky endgr oups frequently lead to lower density coverages and more distorted packings .