X-ray crystallographic and photophysical properties of rhodamine-based chemosensor for Fe3+.

A fluorescent sensor for Fe3+, 2-[3′,6′-bis(ethylamino)-2′,7′-dimethyl-3-oxospiro[1H-isoindole-1,9′-[9H]xanthen]-2-((2-aminoethyl) methyl)]phenol, has been synthesized and characterized by 1H NMR, 13C NMR and X-ray crystallography. The photophysical processes of the Fe3+-sensor have been carefully investigated by fluorescence and absorbance spectra. Upon addition of Fe3+, the sensor shows strong fluorescence change with absorbance and emission peaks at 530 and 554nm, respectively. Other metal ions have no such response.