"Off-on" aggregation-based fluorescent sensor for the detection of chloride in water. Issue 14 (11th March 2015) - Watt, Michelle M.
Abstract : A new class of 2, 6-bis(2-anilinoethynyl)pyridine bisureas exhibits selective turn-on fluorescence for chloride in water. Abstract : Receptors selective for anions in aqueous media are a crucial component in the detection of anions for biological and environmental applications. Recent sensor designs have taken advantage of systems known to aggregate in solution, eliciting a fluorescent response. Herein, we demonstrate a chloride-selective fluorescent response of receptor1 +, based on our well-established class of 2, 6-bis(2-anilinoethynyl)pyridine bisureas. The fluorescence intensity ratio of1 + ·Cl −> aggregates in water is four times larger than the next most fluorescent anion complex, 1 + ·ClO 4 −> . In addition, 1 H NMR spectroscopic titrations demonstrate1 + binds chloride more strongly than other biologically relevant anions in solutions of both DMSO- d 6 and 50/50 DMSO- d 6 /MeCN- d 3 .