Anion binding induced conformational changes exploited for recognition, sensing and pseudorotaxane disassembly

This is the authors' abstract. We don't add key points for this paper.

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.