A Double-Walled Knotted Cage for Guest-Adaptive Molecular Recognition

We
synthesized a double-walled knotted cage from a flexible tripodal
ligand. The characteristic double-walled structure provided a unique
adaptive behavior of the cavity upon inclusion of organic molecules,
which was evidenced by NMR and X-ray measurements. The semiflexible
host framework, restricted by the knotted topology, enabled kinetic
molecular recognition revealing the sequential binding of two different
guests from their mixture.