Kinetic vs thermodynamic self-sorting of cucurbit[6]uril, cucurbit[7]uril, and a spermine derivative.

Cucurbit[6]-, cucurbit[7]-, and cucurbit[6]uril cavitands can be aligned along a spermine derivative axle in a well-defined, kinetically favored sequence at room temperature, and can undergo a reorganization toward a more stable [4]pseudorotaxane bearing three cucurbit[6]uril units upon thermally induced scrambling.