Efficient FRET-based fuorescent ratiometric chemosensors for Fe3+ and its application in living cells

A series of novel FRET-based fluorescent ratiometric chemosensors (L1-L6) were designed and synthesized. Sensor L2 showed reversible and the best selective recognition toward Fe3+ over other metal ions with a detection limit of 0.418 ppm, which can meet the selective requirements for practical application. Experiment results showed that the response behavior of L2 toward Fe3+ is pH independent in weak acid condition (pH 4.0-6.0). In addition, sensor L2 was successfully applied for ratiometric visualization of Fe3+ in living cells.