Selective and colorimetric fluoride anion chemosensor based on s-tetrazines

s-Tetrazine and their derivatives are found to be a class of selective and colorimetric chemosensors for fluoride anions. The supramolecular interaction (anion-pi and charge/electron transfer) between fluoride ion and p-electron deficient tetrazines receptor could facilitate the F--tetrazines electron transfer (ET) event that generates tetrazine(center dot-) radical anion. Accordingly, the color of its solution changed from red to green. Furthermore, the recognition of F- in DMSO is tolerant to water (DMSO-H2O = 9 : 1, v/v) and shows excellent selectivity towards other anions, especially H2PO4- and OAc-.