A Benzothiadiazole-Based Self-Assembled Cage for Cadmium Detection.

A turn-on fluorescent probe, cage , was efficiently self-assembled by condensing 4,4'-(benzothiadiazole-4,7-diyl)dibenzaldehyde and TREN in chloroform. The formation of cage was characterized and confirmed by NMR spectroscopy, mass spectrometry, and theoretical calculations. The yield of cage could be controlled by tuning the reaction conditions, such as the precursor concentration. Interestingly, the addition of 10 equiv of Cd relative to cage could increase the fluorescence almost seven-fold. H NMR and fluorescence experiments indicating fluorescence enhancement may be caused by the decomposition of cage . Such a high selectivity toward Cd implies that the cage could potentially be employed in cadmium detection.