2-Mercaptopyrimidine as a suitable matrix to trap arenes on Au(1 1 1): STM probing of the modified surface

2-Mercaptopyrimidine (2MPy) forms a two-dimensional planar lattice on Au(1 1 1). This structure is able to intercalate guest molecules such as the oligopyridines. To test the ability of the 2MPy lattice as a host able to intercalate a variety of molecules regardless of their geometry and electronic structures, some arenes and polyenes were analyzed as possible guests. Benzene, naphthalene, azulene, phenanthrene, anthracene, biphenyl, fluorobenzene and durene were selected to coadsorb with 2MPy on the Au(1 1 1) surface. These arenes are not known to form stable layers on Au(1 1 1); their adsorption is often studied on Pt and Rh surfaces. The experimental data show that the arenes and polyenes selected coadsorb with 2MPy on Au(1 1 1) under defined experimental conditions, forming a mixed layer with stoichiometry of 2:1 in thiol:guest. The STM contrast observed for the guest molecules is compared to the experimental and theoretical results already published.