title: Anion binding induced conformational changes exploited for recognition, sensing and pseudorotaxane disassembly.
abstract: Investigations to exploit the anion binding induced conformational changes displayed by a new class of acyclic receptor for anion recognition, fluorescence sensing and pseudorotaxane disassembly are described. A series of imidazolium-appended bis-amide-pyridine, pyridine N-oxide and pyridinium containing receptors are synthesised and their anion binding properties elucidated using (1)H NMR spectroscopy. Upon anion recognition, the receptors exhibit a substantial conformational change from an 'open' to a more 'closed' intramolecular geometry. The fluorescence anion sensing ability of a bis-pyrene-functionalised analogue is investigated, with anion-induced responses arising from excimer signalling mechanisms. A pseudorotaxane assembly formed between the pyridine N-oxide receptor acting as a threading component and an isophthalamide macrocycle is demonstrated to undergo disassembly resulting from the conformational behaviour exhibited by the thread upon chloride binding.
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Graeme T
authors.initials: GT
authors.lastname: Spence
authors.forename: Carmen
authors.initials: C
authors.lastname: Chan
authors.forename: Fridrich
authors.initials: F
authors.lastname: Szemes
authors.forename: Paul D
authors.initials: PD
authors.lastname: Beer