Pathway Engineering of Multicomponent Self-Assembly in M12L24 Nanospheres using Pseudorotaxanes

Abstract

Abstract Selective formation of multicomponent structures via the self-assembly of numerous building blocks is ubiquitous in biological systems but challenging to emulate synthetically. The energy landscape for product formation broadens with increasing number of components, introducing kinetic intermediates with trap-state ability. Therefore, pathway engineering becomes an essential tool to navigate these complex kinetic landscapes and push self-assembly to greater limits. Here, we report an example of pathway engineering in the self-assembly of cuboctahedral M12L24 nanospheres through pseudorotaxane formation to the exo-functionalized ligands. Without ring in solution for pseudorotaxane formation, a Pdx–Ly polymer resting-state is rapidly formed. Solutions with ring exhibit rapid nanosphere formation from small Pdx–Ly oligomers, with Pdx–Ly polymer formation bypassed. The threading of ring to an exo-functionalized ligand therefore directs the self-assembly pathway toward nanosphere formation. As the process of pseudorotaxane formation increases rate of nanosphere formation, the ring effectively acts as a supramolecular catalyst for nanosphere self-assembly.