A click end-capping reaction exploiting nitrile N-oxide to rotaxane was described with emphasis of productivity of the protocol via stable C-C bond formation. Establishment of a pH-driven molecular shuttling system was also demonstrated by practical neutralization of the sec-ammonium group of the rotaxane axle with potassium hydroxide.

The effect of rotaxane shuttling on the fluorescence properties of a fluorophore was investigated by exploiting fluorophore-tethered [2]rotaxanes. A fluorescent boron enaminoketonate (BEK) moiety was introduced in a rotaxane via transformation of an isoxazole unit generated as a result of an end-capping reaction using a nitrile N-oxide. The rotaxane exhibited a red shift of the fluorescence maximum along with a remarkable enhancement of the fluorescence quantum yield through wheel translation to the fluorophore.

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