An off-on fluorescent sensor with high selectivity and sensitivity for Fe(III).

A new fluorescent derivative (1) containing coumarin exhibits Fe(III)-selective strong yellow-green fluorescence in ethanol. This compound could be used as an “off-on” chemosensor and allow the detection of Fe3+by monitoring changes in absorption and fluorescence spectra. Upon addition of Fe3+, an overall emission change of 125-fold was observed. High selectivity and sensitivity were observed over other metal ions, mainly due to the spirolactam ring-opening power of Fe3+. The detection limit was as low as 5.6?ppb. Photo-induced electron transfer, coupled with intramolecular charge transfer are proposed to account for the observed spectral response. [ABSTRACT FROM PUBLISHER]