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A new bis-pyridinium calix4pyrrole derivative is reported. This system forms a non-fluorescent complex upon exposure to the chromenolate anion. The resulting supramolecular ensemble binds the pyrophosphate anion with high affinity (Ka = (2.55 ± 0.12) × 107 M−1) in acetonitrile. It exhibits sensitive “turn-on” fluorescence when exposed to tetrabutylammonium pyrophosphate, and does so in preference to other anions, including the fluoride and phosphate anions.
Sokkalingam et al. (Sun,) studied this question.