Control and induction of surface-confined homochiral porous molecular networks

Homochirality is essential to many biological systems, and plays a pivotal role in various technological applications. The generation of homochirality and an understanding of its mechanism from the single-molecule to supramolecular level have received much attention. Two-dimensional chirality is a subject of intense interest due to the unique possibilities and consequences of confining molecular self-assembly to surfaces or interfaces. Here, we report the perfect generation of two-dimensional homochirality of porous molecular networks at the liquid-solid interface in two different ways: (i) by self-assembly of homochiral building blocks and (ii) by self-assembly of achiral building blocks in the presence of a chiral modifier via a hierarchical structural recognition process, as revealed by scanning tunnelling microscopy. The present results provide important impetus for the development of two-dimensional crystal engineering and may afford opportunities for the utilization of chiral nanowells in chiral recognition processes, as nanoreactors and as data storage systems.