Highly sensitive detection of cobalt through fluorescence changes in β-cyclodextrin-bimane complexes.

A supramolecular complex of syn-(methyl,methyl)bimane (1) and β-cyclodextrin demonstrates a sensitive (limit of detection = 0.60 nM) and selective fluorescence turn-off response in the presence of cobalt in aqueous media, with calibration curves enabling quantitation in solution and using filter papers on which bimane and cyclodextrin were adsorbed. 1H NMR spectroscopy provides insight into interactions underlying the sensor performance.