Molecular Graph Paper

We present a self-assembled template of tetraphenylmethane-based variants on a Au(111) surface which feature a periodic lateral arrangement of acetyl groups sticking out of the molecular film. Using the tip of a scanning tunneling microscope, this acetyl group can be removed in a spatially controlled way without a significant effect on the remaining molecular assembly. The chemically modified molecule can readily be distinguished from the original ones such that information can be engraved in the molecular film. Both the modified nature of an individual molecule and the order of the molecular film are shown to persist at room temperature. We show that the mesh size of this molecular graph paper can be tuned by varying the length of the molecular spacer group so that writing and reading information on the nanoscale with variable letter size becomes possible.