A Facile Synthesis of Dynamic Supramolecular Aggregates of Cucurbit[ n ]uril ( n =5–8) Capped with Gold Nanoparticles in Aqueous Media

Supramolecular capping of cucurbit[ n ]uril (CB[ n ]), where n =5–8, by narrowly dispersed gold nanoparticles has been achieved through a facile synthetic route with metastable gold nanoparticles as a labile intermediate. The resultant assemblies were stable in solution, and were found to form dynamic aggregates consisting of a controllable ratio of singly and doubly capped CB[ n ]. The stability of the system was attributed to the presence of sodium cations bound on the vacant carbonyl portals of the singly capped CB[ n ] molecules. These dynamically capped CB[ n ] systems can find potential use in a range of applications varying from ultrasensitive multiplexed in situ sensing to photocatalysis.