Detection of Zn2+ and its imaging in plant roots by a bisphenol A-Based fluorescent chemosensor

Application of a chemosensor for imaging Zn2+ in plant's root has rarely been reported. We report here synthesis and characterization of 4,4′-(propane-2,2-diyl)bis(2-(((2morpholinoethyl)imino)methyl)phenol) (H2L) as a Zn2+ sensor and its application in plant root imaging. It has been synthesized by a reaction between bisphenol A dialdehyde and 2-morpholinoethanamine (1:2 ratio) in methanol under mild condition. It shows significant enhancement (76-fold) in its fluorescence intensity at 473 nm in the presence of Zn2+ ion. Quantum yield of H2L increases from 0.004 to 0.635 upon interaction with the cation. It forms a 1:2 complex (ligand/metal) with an association constant of 2.89 × 105 M−2. The limit of detection has been determined as 7.05 × 10-8 M signifying high sensitivity. Fluorescence increment of the probe has been attributed to chelation enhanced fluorescence (CHEFF) mechanism and restriction of CN isomerization. H2L has been successfully utilized to image Zn2+ in rice plant's root.