A Simple Perceptive Diphenyl-Imidazole-Based Dipodal Schiff-Base Chemosensor for Zn2+ and PPi ions and Its Live-Cell Imaging Applications

2,6-bis((E)-(2-(benzo[d]thiazol-2-yl)hydrazono)methyl)-4-(4,5-diphenyl-1H-imidazol-2-yl)phenol (PIS) conjugate has been designed as a selective fluorescent probe for zinc ion. The PIS exhibits selectivity towards Zn2+ among various ions in DMSO-H2O (1:9) v/v 50 mM HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) at pH=7.4. Moreover, the detection of PIS towards Zn2+ ion could be realized in (")naked eye" with a color conversion from yellow to greenish yellow. The linear relationship between fluorescence intensity and Zn2+ ion concentration indicates that PIS can be used for quantification of Zn2+ ion. The PIS probe can be used in broad pH ranging from 4 to 9. The limit of detection (LOD) was found to be 0.52 nM for Zn2+ ion. The binding ratio and binding constant of PIS-Zn2+ complex were determined and calculated as 1:1 and 2.36x10(6) M-1 according to Job ' s plot and Benesi-Hildebrand equation, respectively. Furthermore, the PIS-Zn2+ complex subsequently acted as a secondary fluorescent turn-off probe for pyrophosphate (PPi) ion recognition among the other anions. To assess the real-world efficacy of the PIS and PIS-Zn2+ complex, they were evaluated by test paper strips. Likewise, the probe PIS and PIS-Zn2+ complex were used as in vitro cell imaging probe, and successfully demonstrated as feasible bio-marker as well.