On-Surface Synthesis of Organic Molecules and Nanoarchitectures by Scanning Probe Manipulation

On-surface synthesis is at the verge of emerging as the method of choice for the generation and visualization of new molecules and molecular assemblies. In particlar constructing low-dimensional covalent assemblies with tailored size and connectivity is challenging yet often key for applications in molecular electronics where optical and electronic properties of the quantum materials are highly structure dependent. We present a versatile approach for building such structures block by block on bilayer sodium chloride (NaCl) films on Cu(111) with the tip of an atomic force microscope, while tracking the structural changes with single-bond resolution. Covalent homo-dimers in cis and trans configurations and homo-/hetero-trimers were selectively synthesized by a sequence of dehalogenation, translational manipulation and intermolecular coupling of halogenated precursors. Further demonstrations of structural build-up include complex bonding motifs, like carbon–iodine–carbon bonds and fused carbon pentagons. Further we present an example for the on-surface synthesis of an structurally elusive molecule, P₃N₃, the inorganic aromatic analogue of benzene, not obtainable via traditional synthetic methods. Our work presents strategies for synthesizing elusive molecules as well as covalent nanoarchitectures, studying structural modifications and revealing pathways of intermolecular reactions.