Synthesis of a Pyrene-Derived Schiff Base and Its Selective Fluorescent Enhancement by Zinc and Aluminum Ions

An efficient pyrene-Schiff base fluorescent sensor PySb was synthesized and evaluated for its fluorescence response to metal ions. Sensor PySb exhibits an “off-on-type” mode with high selectivity to Zn2+ and Al3+ in ethanol (470 nm) and in dimethyl sulfoxide (458 nm) respectively. The originally non-fluorescent PySb, due to photo-induced electron transfer (PET) from imine moiety, is turned on after binding with the cations. The stoichiometric ratio between PySb and Zn2+ is 1:2; moreover, the limit of detection (LOD) and bonding constant were 2.39 × 10-8 M and 2 × 109 M-1 respectively, as obtained from titration experiments.