Highly selective probe based on imine linkage for Zn2+ and HSO3− in mixed aqueous media

Abstract A simple salicylaldehyde derived Schiff base N, N ′- bis (p-chloro salicylidene)-1, 2- ethylenediamine (L) was synthesized and characterized. The receptor demonstrates simultaneous dual channel chromogenic and fluorogenic signaling towards HSO 3 − and Zn 2+ in mixed aqueous media. Solvatochromism was employed systematically for modulating its optoelectronic properties. The probe was successfully assessed to monitor HSO 3 − detection via UV–vis spectroscopy. DFT calculations and 1 H NMR spectroscopy further support the results based on shifting of equilibrium. Moreover, the sensor showed large fluorescence enhancement with blue-shift of 48 nm after addition of Zn 2+ . The probe exhibits high selectivity over other competitive ions with high detection limit of 6.54×10 −5  M and 3.21×10 −6  M for HSO 3 − and Zn 2+ , respectively. Importantly, this is one of the rare reports in which Schiff base was utilized for the fabrication of chromogenic or fluorogenic sensor using solvent effect for multianalyte detection.