Cooperative Sulfate Binding Drives Hierarchical Assembly of Supramolecular Trimers

electrostatic attraction. The trimer remains stable in solution, as confirmed by NMR, DOSY, and ESI-MS experiments. Concentration-dependent NMR studies elucidate a multistep assembly pathway from a 1:1 sulfate complex, through a figure-eight subunit, to the final architecture. Moreover, replacing the non-coordinating pyridine unit with a chiral group successfully induces enantiopure trimers. This work establishes a paradigm of anion-dictated assembly through cooperative first- and second-sphere coordination, offering a new avenue for supramolecular assemblies.