Development of Acridine‐Derived “Turn On” Al 3+ Fluorescent Sensors and Their Imaging in Living Cells

Two novel highly selective fluorescent sensors L‐1 and L‐2 for the determination of Al 3+ ion were synthesized and characterized. The sensors acridine‐4,5‐diylbismethyl(bis(oxy))bis(2,1‐phenylene))bis‐(methylene))bis(azanediyl))bis(3‐phenylpropan‐1‐ol) ( L‐1) and 2,2′‐acridine‐4,5‐diylbis(methylene(bis(oxy))bis(2,1‐phenylene))bis‐(methylene))bis(azanediyl))bis(propan‐1‐ol) ( L‐2) showed “turn on” fluorescence response in the presence of Al 3+ ion in DMSO/tris‐HCl (1:1, v:v, pH=7.2) buffer solution. Other cations viz. Li + , Na + , K + , Mg 2+ , Ca 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cd 2+ , Cu 2+ , Zn 2+ , Mn 2+ , Ba 2+ , Pb 2+ , Hg 2+ , Fe 3+ and Eu 3+ ions showed no appreciable change in fluorescence spectrum. The detection limits of L‐1 and L‐2 for Al 3+ ion were at the parts per billion level. In addition, possible utilization of sensors as bio‐imaging fluorescent sensors to detect Al 3+ in human cervical HeLa cells was also investigated by confocal fluorescence microscopy.