Dynamic Stereochemistry of M Pd Supramolecular Cages Based on Metal-Center Lability for Differential Chiral Induction, Resolution, and Recognition.

A series of isostructural supramolecular cages with a rhombic dodecahedron shape have been assembled with distinct metal-coordination lability (M Pd -MOC-16, M=Ru , Fe , Ni , Zn ). The chirality transfer between metal centers generally imposes homochirality on individual cages to enable solvent-dependent spontaneous resolution of Δ /Λ -M Pd enantiomers; however, their distinguishable stereochemical dynamics manifests differential chiral phenomena governed by the cage stability following the order Ru Pd >Ni Pd >Fe Pd >Zn Pd . The highly labile Zn centers endow the Zn Pd cage with conformational flexibility and deformation, enabling intrigue chiral-Δ /Λ -Zn Pd to meso-Δ Λ -Zn Pd transition induced by anions. The cage stabilization effect differs from inert Ru , metastable Fe /Ni , and labile Zn , resulting in different chiral-guest induction. Strikingly, solvent-mediated host-guest interactions have been revealed for Δ /Λ -(Ru/Ni/Fe) Pd cages to discriminate the chiral recognition of the guests with opposite chirality. These results demonstrate a versatile procedure to control the stereochemistry of metal-organic cages based on the dynamic metal centers, thus providing guidance to maneuver cage chirality at a supramolecular level by virtue of the solvent, anion, and guest to benefit practical applications.