A supramolecular five-component relay switch that exposes the mechanistic competition of dissociative versus associative binding to cucurbiturils by ratiometric fluorescence monitoring.

A putrescine derivative of aminomethyladamantane is established as a ditopic guest with two mutually exclusive binding sites for cucurbit[6]uril and cucurbit[7]uril. A mixture containing both hosts, the ditopic guest, and two fluorescent dyes affords a relay system with a ratiometric fluorescence response and enables a kinetic analysis of the switching mechanism.