Water-Gated Allosteric Reconfiguration of a Lanthanide-Organic Cage Dynamically Modulates Fullerene Chiroptical...

Dynamic control over both the chiroptical response and radical persistence of fullerene within a single adaptive host remains challenging. Here we report that a trace amount of water serves as a key to gate a fullerene-assisted vertex-chirality inversion in an allosteric lanthanide coordination cage, converting C₆₀⊂Δ₄P₄ into C₆₀⊂Λ₄P'₄. The switch proceeds via a concerted architectural reset, featuring ∼20% cavity contraction, near-closure of the cage windows, and strengthened host-guest contacts, yielding a thermodynamically more stable complex under aqueous perturbation. Confinement within the compact Λ₄P'₄ cavity inverts and amplifies the induced chiroptical response of encapsulated C₆₀ (×3.5, |g_abs| = 1.62 × 10^-2), the highest value reported for noncovalent chiral induction of C₆₀ in solution, while switching C₆₀ ^•- from a short-lived state (<4 min) in the pre-inversion cage to a substantially more persistent state (∼2 h) in the post-inversion cage. These effects arise from enhanced concave-convex π-π/dispersion interactions that stabilize the post-inversion host-guest state. By linking water-triggered allosteric reconfiguration to both chiral information transfer and radical persistence, this work establishes adaptive coordination cages as active regulators of fullerene electronic and chiroptical states, providing a strategy for programming coupled chirality and redox functions in carbon nanostructures.