A supramolecular assembly controlled by anions: threading and unthreading of a pseudorotaxane

Abstract

The pseudorotaxane formed in CH₂Cl₂ solution by (9-anthrylmethyl)methylammonium hexafluorophosphate salt and dibenzo-24-crown-8 can be unthreaded by addition of NBu₄Cl through the formation of a strong ammonium chloride ion pair, while pseudorotaxane rethreading can be performed by addition of NHBu₃PF₆; all these processes can be followed by pronounced changes in the luminescence spectra, which could allow the use of this system as a fluorescent sensor for chloride ions.