An Acid-triggered Reactive and Enhanced Fluorescent Probe for Selective Detection of Al3+/H+ and its Application in Real Water Samples and Living Cells.

A reactive fluorescent "turn-on" probe (di-PIP) with imine-linked dual phenanthro[9,10-d]imidazole luminophore have been conveniently prepared as an Al3+ and H+ dual functional receptor. di-PIP displayed high selectivity and sensitivity towards Al3+ ion in DMF/HEPES accompanied by fluorescence blue-shift and a good linear relationship as well as a low detection limit of 30.5 nmol·L-1, which can root from the synergetic functions of the decomposition reaction of di-PIP promoted by acidic Al3+ and the coordination effect between decomposition product and Al3+. Intriguingly, it was found that hydrogen ion H+ can be sufficient for simulating the fluorescence enhancing of di-PIP. 1H NMR titration and MS analyses for elucidation of the intermediate structure further revealed that the acid-triggered decomposition reaction resulted in the rapid, and sensitive sensing to Al3+ and H+. In addition, the probe di-PIP could be successfully applied to the detection of Al3+ in real water samples, and also utilized to visualize Al3+ and H+ in the living cells.