A chromone-derived Schiff-base as Al3+ "turn-on" fluorescent probe based on photoinduced electron-transfer (PET) and C=N isomerization

In this study, a novel chromone-derived Schiff-base ligand which was called bis(6-hydroxychromone-3-methylidene)-o-phenylenediimine (1) was designed, synthesized, and evaluated as an Al3+ "turn on" fluorescent probe. This probe 1 showed good selectivity and high sensitivity towards Al3+ in the presence of most metal ions, and a remarkable enhancement by about 30.91-fold in fluorescence emission intensity at 459 nm was observed with addition of 1 equiv of Al3+, which was attributed to the inhibition of photoinduced electron-transfer (PET) phenomenon and C=N isomerization process at the excited state. Moreover, the fluorescence response of 1 to Al3+ was nearly completed within 10 min. Thus, this probe 1 could be utilized for sensing and monitoring Al3+ in environmental and biological systems for real-time detection. (C) 2016 Elsevier Ltd. All rights reserved.