A New Fluorescence Turn‐On Probe for Aluminum(III) with High Selectivity and Sensitivity, and its Application to Bioimaging

The development of novel selective probes with high sensitivity for the detection of Al 3+ is widely considered an important research goal due to the importance of such probes in medicine, living systems and the environment. Here, we describe a new fluorescent probe, N ′‐(4‐diethylamino‐2‐hydroxybenzylidene)‐2‐hydroxybenzohydrazide ( 1 ), for Al 3+ . Probe 1 was evaluated in a solution of acetonitrile/water (1:1 v / v ). Compared with previously reported probes for Al 3+ , probe 1 can be synthesized easily and in high yield. A Job plot confirmed that probe 1 is able to complex Al 3+ in a 1:1 ratio, and the binding constant was determined to be 4.25×10 8   m −1 . Moreover, the detection limit was as low as 6.7×10 −9   m , suggesting that probe 1 has a high sensitivity. Common coexistent metal ions, such as K + , Co 2+ , Ca 2+ , Ba 2+ , Ni 2+ , Pb 2+ , Hg 2+ , Ce 2+ , Zn 2+ , Cd 2+ , Fe 3+ , showed little or no interference in the detection of Al 3+ in solution, demonstrating the high selectivity of the probe. Finally, the ability of probe 1 to act as a fluorescent probe for Al 3+ in living systems was evaluated in Gram‐negative bacteria, Escherichia coli , and confocal laser scanning microscopy confirmed its utility. The results of this study suggest that 1 has appropriate properties to be developed for application as a fluorescent probe of Al 3+ for use in biological studies.