Acid/Base‐ and Anion‐Controllable Organogels Formed From a Urea‐Based Molecular Switch

Abstract

A switch in time: Gel–sol transitions of a urea-based [2]rotaxane gelator are controlled by the degree of solvent exposure of the hydrogen-bond-donating urea station and the orientation of the hydrogen-bond-accepting CO groups of the interlocked ethylene glycol based macrocycle (N blue, O and macrocycle red, phenyl green). Both acid/base and anion-exchange control can be used to reversibly transition the rotaxane in 1-pentanol between solution and gel states.