Surface-mediated ordering of pristine Salen molecules on coinage metals

Abstract

The adsorption and assembly of pristine Salen molecules have been investigated by low-temperature scanning tunneling microscopy (STM) on Au(111), Ag(111) and Cu(111). High-resolution STM imaging reveals that the Salen molecules form three types of conformational isomers and several self-assembled unit structures on Au(111) and Ag(111). However, the morphology, proportional distribution and self-assembled structure of Salen on Cu(111) are different from those on Au(111) and Ag(111) because the Cu(111) substrate invokes a relatively stronger molecule-substrate interaction. This study demonstrates that the conformational changes of the pristine Salen molecule can be mediated by the underlying substrate lattice structure, leading to subsequent formation of self-assembled structures on the surface.