Na+ Ion Templated Threading of Oligo(ethylene glycol) Chains through BPX26C6 Allows Synthesis of [2]Rotaxanes under Solvent-Free Conditions

Threading of di-, tri-, and tetra(ethylene glycol) through the macrocycle BPX26C6 in the presence of templating Na+ ions was proven by the synthesis of the corresponding [2]rotaxanes under solvent-free conditions. Among them, a [2]rotaxane featuring both tetra(ethylene glycol) and carbamate stations behaves as a molecular switch that can be controlled reversibly through the application of the KTFPB/[2.2.2]cryptand reagent pair.