Construction of Photo-Responsive Pd2L4-Type Nanocages based on Feringa's Second-Generation Motor and Its Guest Binding Ability for C-60

We present the construction of a M2L4-type metal-organic nanocage featuring four endohedral Feringa's motor motifs and its adaptive encapsulation towards a C-60 guest molecule. The structure of the cage, though complicated on the H-1 NMR spectrum due to the adoption of mixed ligands, was unambiguously characterized with a combination of ESI-MS, 2D DOSY, C-13 NMR and particularly the SAXS technique. The molecular motor within the cage demonstrated similar photophysical properties to the uncoordinated one, indicating the motor's function was not compromised when it was anchored in such a confined nanospace. Furthermore, the nanocage showed good guest encapsulation ability towards C-60, and a guest induced-fit behavior of the cage was revealed based on the extensive SAXS analysis and molecular dynamics simulation. The adaptive motorized nanocage reported here represents one of the very few examples of integrating individual motors into a discrete nanoconfined system and offers prospects to achieve its non-equilibrium functions.