A selective diaminomaleonitrile-based dual channel emissive probe for Al3+ and its application in living cell imaging.

A selective diaminomaleonitrile-based fluorescent probe for Al3+(L) has been synthesized and characterized. The sensing behavior of L towards different metal ions was investigated by fluorescent spectra and competition experiment. The results showed that L exhibited a dual channel emission (λem 522 & 558 nm) with yellow fluorescence in the presence of Al3+ over other metal ions in EtOH solution. The probe L was bound to Al3+ in a 1:2 stoichiometric manner as supported by Job's plot analysis. The binding constant was 9.55 × 108 M-2 with the detection limit of 10.3 nM. The turn-on response was attributed to the inhibition of PET and CN isomerization after binding with Al3+ while the dual emissions were due to ESIPT and ICT processes. In addition, the application of L for imaging Al3+ in living Hela cells was achieved.