A novel ratiometric fluorescent Fe3+ sensor based on a phenanthroimidazole chromophore

Phenanthroimidazole derivative 1 has been developed as a rare example of ratiometric fluorescent sensors for Fe(3+). Interestingly, upon treatment with Fe(3+), the sensor displayed a ratiometric fluorescent response with an enhancement of the ratios of emission intensities at 440 and 500 nm from 0.36 to 3.24. The detection range of the sensor for Fe(3+) is in the 1.0x10(-5)-1.5x10(-4) M concentration range and the detection limit is 5.26x10(-6) M. In addition, the sensor showed good selectivity to Fe(3+) with the selectivity coefficients (K(Fe3+) = S(Fe3+)/S(0) of Fe(3+) over other metal ions tested in the range of 5-68.