An Unsymmetrical bis-Imine Derivative for Solvent Dependent Rapid Optical Discrimination of Al3+, Zn2+ and OCl-: Combined Experimental and Theoretical Studies

An unsymmetrical bis-imine derivative (A2) selectively detect Al3+, Zn2+ and OCl- in a solvent dependent manner where Al3+ and Zn2+ emit green and blue light in DMSO-H2O media while OCl- emits green-yellow light in aqueous ethanol. The corresponding florescence enhancements are 8.2 fold, 3.7 fold (chelation enhanced fluorescence and excited state intra-molecular proton transfer OFF) and 10.6 fold (H-bonding, excited state intra-molecular proton transfer OFF) respectively. While the limit of detection (LODs) for Al3+, Zn2+ and OCl- are 49 nM, 35 nM and 74 nM respectively, the corresponding binding/ association constants are 1.79x10(5) M-1, 1.8x10(5) M-1 and 3.68x10(5) M-2. The results of density functional theory (DFT) studies are fairly close to that of experimental findings.