The allosteric regulation
of biomolecules, such as enzymes, enables
them to adapt and alter their conformation to fit specific substrates,
expressing different functionalities in response to stimuli. Different
stimuli can also trigger synthetic coordination cages to change their
shape, size, and nuclearity by reconfiguring the dynamic metal–ligand
bonds that hold them together. Here we demonstrate an abiological
system consisting of different organic subcomponents and ZnIImetal ions, which can respond to simple stimuli in complex ways.
A ZnII20L12dodecahedron transforms
to give a larger ZnII30L12icosidodecahedron
through subcomponent exchange, as an aldehyde that forms bidentate
ligands is displaced in favor of one that forms tridentate ligands
together with a penta-amine subcomponent. In the presence of a chiral
template guest, the same system that produced the icosidodecahedron
instead gives a ZnII15L6truncated
rhombohedral architecture through enantioselective self-assembly.
Under specific crystallization conditions, a guest induces a further
reconfiguration of either the ZnII30L12or ZnII15L6cages to yield an unprecedented
ZnII20L8pseudo-truncated octahedral
structure. The transformation network of these cages shows how large
synthetic hosts can undergo structural adaptation through the application
of chemical stimuli, opening pathways to broader applications.