A turn-on fluorescence probe for Fe3+ based-on benzimidazo[2,1-α]benz[de]isoquinoline-7-one derivatives

A novel fluorescent chemosensor L based on benzimidazo[2,1-α]benz[de] isoquinoline-7-one-12-carboxylic acid as fluorophore with ethyl-2-(2-aminothiazol-4-yl)-2-(hydroxyimino)acetate as receptor was developed. L in CH3CN/H2O (v/v = 9:1, 5 mM tris, pH = 7.4) exhibited selectively fluorescence “off-on” pattern for Fe3+. Moreover, the detection limit of L for Fe3+ was 9.0 × 10−8 M. In addition, ESI-MS confirmed 1:1 stoichiometry ratio of L with Fe3+. DFT theory calculations was used to prove the hypothetical PET mechanism.