Chiral nanoporous networks featuring various chiral vertices from an achiral molecule on Ag(100)

Chiral nanoporous nanoarchitectures exhibit potential applications in various fields including chiral separation, sensing and catalysis. Two-dimensional (2D) supramolecular chemistry offers novel methods to build chiral nanoporous networks from achiral molecules. Herein, we report a series of chiral nanoporous networks built by an achiral precursor molecule via a stepwise annealing strategy on Ag(100). The nanoporous network morphologies and structural details are characterized by high-resolution scanning tunneling microscopy (STM). It is revealed that all vertices within networks are chiral. These chiral vertices are either dimeric, trimeric, or tetrameric. The connection of these chiral vertices gives rise to diverse chiral nanopores with varying shapes and sizes. A strict chirality correlation between nanopores and their vertices is determined. Specifically, enantiomeric vertices of one-pair nanopore enantiomers are always in identical type but opposite handedness. This work serves as a model to investigate the influence of vertex chirality on nanopore chirality of a supramolecular matrix. The attained chiral nanopores could potentially be utilized as templates for surface reaction, chiral recognition, etc. The mirror-symmetric silver adatoms clusters dictated by chiral nanopore are discerned.