Selective Synthesis of a [3]Rotaxane Consisting of Size-Complementary Components and Its Stepwise Deslippage

An α-cyclodextrin-based size-complementary [3]rotaxane with an alkylene axle was selectively synthesized in one pot via an end-capping reaction with 2-bromophenyl isocyanate in water. Thermal degradation of the [3]rotaxane product yielded not only the original components but also the [2]rotaxane. Thermodynamic studies suggested a stepwise deslippage process

Thermoresponsive Shuttling of Rotaxane Containing Trichloroacetate Ion

A thermoresponsive rotaxane shuttling system was developed with a trichloroacetate counteranion of an ammonium/crown ether-type rotaxane. Chemoselective thermal decomposition of the ammonium trichloroacetate moiety on the rotaxane yielded the corresponding nonionic rotaxane accompanied by a positional change of the crown ether on the axle. The rotaxane skeleton facilitated effective dissociation of the acid, markedly lowering the thermal decomposition temperature