Doubly Docked Pseudorotaxanes

Abstract

The snug fit of two suitably spaced dialkylammonium centers within the cavity of the macrocyclic polyether bis-p-phenylene[34]crown-10 (BPP34C10) generates [2]pseudorotaxanes in which each cationic ammonium center “docks” with one of the macrocycle's two polyether loops (right), for the most part by means of hydrogen bonds. One such doubly docked [2]pseudorotaxane forms the basis of a prototypical chromophoric supramolecular switch triggered by alterations to the surrounding pH.