Ordered Growth of Upright Melamine Species on Ni{111}: A Study with Scanning Tunnelling Microscopy and Reflection Absorption Infrared Spectroscopy

Melamine (1,3,5-triazine-2,4,6-triamine) is a common building block used in the construction of 2-D H-bonded architectures at surfaces. Previous work investigating the adsorption of melamine has focused on relatively unreactive surfaces where intermolecular H-bonding interactions dominate over molecule-surface interactions. In this study, the adsorption of melamine was investigated on the more reactive Ni{111} surface under ultrahigh vacuum conditions. Molecular packing and conformation are investigated with scanning tunnelling microscopy and reflection absorption infrared spectrocopy (RAIRS). The adsorption behavior was found to be strongly influenced by the substrate with RAIRS, indicating that the molecular plane is aligned approximately perpendicular to the surface. Thermally stable 1-D chains of partially dehydrogenated melamine are formed on the Ni surface aligned along the <-211 > crystallographic directions.