Complex k-uniform tilings by a simple bitopic precursor self-assembled on Ag(001) surface

The realization of complex long-range ordered structures in a Euclidean plane presents a significant challenge en route to the utilization of their unique physical and chemical properties. Recent progress in on-surface supramolecular chemistry has enabled the engineering of regular and semi-regular tilings, expressing translation symmetric, quasicrystalline, and fractal geometries. However, the k-uniform tilings possessing several distinct vertices remain largely unexplored. Here, we show that these complex geometries can be prepared from a simple bitopic molecular precursor – 4,4’-biphenyl dicarboxylic acid (BDA) – by its controlled chemical transformation on the Ag(001) surface. The realization of 2- and 3-uniform tilings is enabled by partially carboxylated BDA mediating the seamless connection of two distinct binding motifs in a single long-range ordered molecular phase. These results define the basic self-assembly criteria, opening way to the utilization of complex supramolecular tilings.This research has been financially supported by the Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (LQ1601) under the National Sustainability Programme II and project CEITEC Nano+ (CZ.02.1.01/0.0/0.0/16_013/0001728) under programme OPVVV. This research was in part supported by the Horizon 2020 (project SINNCE, No. 810626) and GAČR (project No. 19-01536S). The research was carried out using the CEITEC Nano Research Infrastructure (MEYS, 2016–2019)