Fluoride-triggered ESPT in the binding with sal(oph)en.

In this paper, anion binding and sensing affinity of the simple and easy-to-make salen, a typical class of ligand used comprehensively in metal coordination, was investigated. Results indicated that salophen was both a colorimetric and fluorescent selective chemosensor for fluoride ion, which operated by the anion-induced conformational changes and subsequently excited-state intramolecular proton transfer (ESPT) process. The F(-)-induced quick response, as well as noticeable optical changes, suggested that anion-sensing mechanism maybe help to design and to synthesize the new preferential selective probes for F(-).