Spontaneous Resolution of Chiral Janus-Type Double-Layered Metallocyclic Strips Incorporating Möbius Ring and Circular Helicate

Homochiral metal-organic macrocyclic complexes are of great significance owing to their chirality and well-defined internal cavities that potentially have the ability to mimic complicated biological processes. Here we report a novel metal/anion-coordination co-driven strategy for the formation of nanoscale supramolecular metallocycles with unique topology, large size, and desired chirality. The enantiomeric Janus-type metallocyclic strips are assembled based on the synergistic coordination of sulfate anions and CoII ions to a bifunctional achiral ligand combining the o-phenylene-(bis)urea anion-chelating and 8-hydroxyquinoline metal-coordinating sites. The inherent chirality arises from two types of helical chiralities (triply twisted Möbius ring and circular helicate), which is observed for the first time for metal-organic complex systems. Notably, spontaneous chiral resolution by conglomerate crystallization into a pair of enantiomers (P- or M-Co9) is realized, which is attributed to the multiple weak intermolecular interactions facilitating the hierarchically helical superstructure.