Construction of outward-everted metal-organic cages induced by steric hindrance groups based on dissymmetrical ligands

Steric hindrance groups hold a pivotal role in the self-assembly process of biomolecules. Building on this insight, a strategy for synthesizing outward-everted molecular cages by endo-modification of steric hindrance groups on dissymmetrical ligands is proposed in this work. Specifically, the dissymmetrical ligands have been endomodified with five distinct bulky hindrance groups, and they are respectively assembled with Pd(II). In order to relieve steric crowding, all hindering groups are oriented outward from the cage, and the arrangement of the two dissymmetrical ligands between adjacent Pd(II) is opposite, indicating high flexibility in regulation. As a result, a low-symmetry hexameric or octameric cage with dissimilar chemical environments for the ligands can be assembled. This work provides valuable insights and has significant implications for the construction of new supramolecular systems.