Coverage‐Controlled Superstructures of C3‐Symmetric Molecules: Honeycomb versus Hexagonal Tiling

Torben Jasper‐Tönnies,Richard Berndt,Manuel Gruber,Sandra Ulrich,Rainer Herges

doi:10.1002/anie.202001383

Torben Jasper‐Tönnies, Richard Berndt + Show 3 more

Open Access

https://doi.org/10.1002/anie.202001383

Copy DOI

Abstract

The competition between honeycomb and hexagonal tiling of molecular units can lead to large honeycomb superstructures on surfaces. Such superstructures exhibit pores that may be used as 2D templates for functional guest molecules. Honeycomb superstructures of molecules that comprise a C3 symmetric platform on Au(111) and Ag(111) surfaces are presented. The superstructures cover nearly mesoscopic areas with unit cells containing up to 3000 molecules, more than an order of magnitude larger than previously reported. The unit cell size may be controlled by the coverage. A fairly general model was developed to describe the energetics of honeycomb superstructures built from C 3 symmetric units. Based on three parameters that characterize two competing bonding arrangements, the model is consistent with the present experimental data and also reproduces various published results. The model identifies the relevant driving force, mostly related to geometric aspects, of the pattern formation.

Highlights

Molecular self-assembly on substrates may be used to fabricate desired nanostructures on surfaces
A fairly general model was developed to describe the energetics of honeycomb superstructures built from C3 symmetric units
Often weak interactions are used such as hydrogen bonding, dispersion forces, p–p stacking, metal coordination, and electrostatic interactions.[2,3,4,5]

Summary

Introduction

Molecular self-assembly on substrates may be used to fabricate desired nanostructures on surfaces. The assembly process is initiated and controlled by the molecule–substrate and molecule–molecule interactions. The former interaction ideally ensures the stable adsorption of the molecules and their efficient diffusion on the surface at suitable temperatures.[1] The molecule–molecule interactions usually determine the self-assembled molecular patterns. Often weak interactions are used such as hydrogen bonding, dispersion forces, p–p stacking, metal coordination, and electrostatic interactions.[2,3,4,5] Local, directional, and selective molecule– molecule interactions, for example, hydrogen bonding and metal coordination, are attractive because they enable further control of the patterns via suitable design of molecules.[6]

Results

Discussion

Conclusion