On‐Surface Synthesis of Porous Carbon Nanoribbons on Silver: Reaction Kinetics and the Influence of the Surface Structure

Abstract

We report on the influence of the surface structure and the reaction kinetics in the bottom‐up fabrication of porous nanoribbons on silver surfaces using low‐temperature scanning tunneling microscopy. The porous carbon nanoribbons are fabricated by the polymerization of 1,3,5‐tris(3‐bromophenyl)benzene directly on the Ag surface using an Ullmann‐type reaction in combination with dehydrogenative coupling reactions. We demonstrate the successful on‐surface synthesis of porous nanoribbons on Ag(111) and Ag(100) even though the self‐assemblies of the intermediate organometallic structures and covalently‐linked polymer chains are different on both surfaces. Furthermore, we present the formation of isolated porous nanoribbons by kinetic control. Our results give valuable insights into the role of substrate‐induced templating effects and the reaction kinetics in the on‐surface synthesis of conformationally flexible molecules.

Topology Selectivity in On-Surface Dehydrogenative Coupling Reaction: Dendritic Structure versus Porous Graphene Nanoribbon

“…The proposed chemical structure of this pore-containing dimer is shown in the inset of Figure f, which depicts a covalent product generated by a double C–C bond coupling. The DFT simulated STM image (Figure h) and previous results support our deduction of the molecular structure. For convenience in the statements below, we indicate the C–C connection forming a pore-containing dimer as “D” type, in contrast to the “S” type forky dimer from the single C–C covalent bond formation (Figure g,h).…”

Theoretical Modeling of the Metal‐Organic Precursors of Anthracene‐Based Covalent Networks on Surfaces

“…In practice, this problem can be quite challenging when many isomers of a given tecton have to be considered and experimentally probed. Moreover, when some of these building blocks are additionally able to adopt multiple adsorbed conformations, for example mirror image forms, predicting structure formation in such systems can be very difficult [26,27] . An useful tool which can facilitate these efforts has been the theoretical modeling, enabling easy modification of the parameters characterizing molecular tectons.…”

Halogenated Anthracenes as Building Blocks for the On-Surface Synthesis of Covalent Polymers: Structure Prediction with the Lattice Monte Carlo Method

“…Numerous experimental studies have shown that a careful choice of halogenated aryl monomers results in the formation of polymers, and first their precursors, with predefined structural properties. − In this case, by tuning molecular shape, size, and position of reactive centers (halogens) in the backbone, it has been possible to direct the metal–organic self-assembly and further polymerization toward diverse adsorbed architectures. However, in the case of more complex monomers, with many possible halogen positions, this task can be quite challenging. − For these building blocks, a small change in the position of a halogen(s) can have a significant impact on the morphology of the resulting polymer. For that reason, experimental testing of a series of potential building blocks is necessary, aiming at the selection of the optimal one.…”