(284a) Photoswitching Polymer Network Topology

Topology is a global characteristic of polymer network structure; yet, to our knowledge, there are no examples of polymer networks with externally and selectively switchable topology. Here, we prepare supramolecular polymer metal-organic cage/polyhedra (polyMOC) gels that feature MOC junctions that can be switched between Pd₃L₆ and Pd₂₄L₄₈ metal-ligand stoichiometries in response to green and ultraviolet (UV) light, respectively, to produce reversible changes in the network topology. These polyMOCs display vastly different static and dynamic properties depending on their topological state, which underscores the fundamental impact of topology on polymer network structure and properties. This work establishes topology-switching as a concept for the design of stimuli-responsive supramolecular networks.