Phase Separationof Binary Triptycenes by an IodineInterlayer Film on a Ag(111) Surface

We report the self-assembly behaviors of two triptycenes (Trip-<b>1</b> and Trip-<b>2</b>) on metal surfaces without and with an iodine passivation interlayer by combining scanning tunneling microscopy (STM) and density functional theory (DFT) studies. On the Ag(111) surface, Trip-<b>1</b> molecules form islands through intermolecular aldehyde–aldehyde hydrogen bonding and π–π stacking of benzene rings. In contrast, Trip-<b>2</b> molecules lie flat and dispersed on the surface. The introduction of Trip-<b>2</b> molecules can break the ordered assembly of Trip-<b>1</b>. Trip-<b>1</b> and Trip-<b>2</b> molecules will be mixed in a disorderly manner. On the iodine-passivated Ag(111) surface, Trip-<b>1</b> molecules form islands of long chains by intermolecular aldehyde–aldehyde hydrogen bonding. Trip-<b>1</b> and Trip-<b>2</b> molecules will automatically be separated, forming a self-assembled binary monolayer. These results show that the interface can adjust the mixture and separation of two structurally analogous triptycenes.