Highly selective ratiometric fluorescent detection of Fe3+ with a polyphenyl derivative

Compared with other fluorescent probes, ratiometric fluorescence responses are more attractive because the ratio between the two emission intensities can be used to measure the analyte concentration and provide a built-in correction for environmental effects. A highly selective and sensitive ratiometric fluorescent probe for Fe3+ was synthesized, which exhibits an enhanced fluorescence with a large red-shift in emission from 361 to 455 nm upon addition of Fe3+. The red-shift of the emission peak can be ascribed to the reformed orbital, and the increase of emission intensity may be ascribed to the inhibition of the rotation of C–C bonds between each two aromatic rings.