Progress Towards the Synthesis of Water-Soluble Rotaxane Stoppers

Mechanically interlocked molecules (MIMs) have a wide range of applications as molecular machines from switches to motors. The synthesis of a water-soluble MIM would allow for applications in aqueous environments, where all of life's processes occur. In order to form a water-soluble rotaxane, the host, guest and stopper components must all individually be water-soluble. In this research, four potentially water-soluble stoppers were investigated, two charged and two neutral. 1H NMR and 13C NMR were used to characterize the compounds in each of the routes. Both of the charged stoppers were unable to be synthesized due to equilibrium and solubility complications. More progress was made towards the synthesis of the neutral stoppers and continued work is being done to synthesize these compounds. The synthesis of a fully water-soluble rotaxane could have incredible bio-medical applications.