Highly selective fluorescent and colorimetric methylphenyl-based sensor towards Zn2+ ion detection: Synthesis, X-ray crystallography and selectivity studies

Abstract

A salicylaldehyde based Schiff base (E)-2-(((3-bromo-4-methylphenyl)imino)methyl)-4-chlorophenol (BMIM) was prepared and characterized using various spectral techniques viz., UV–Visible, FT-IR, 1H and 13C NMR, ESI-MS and single crystal XRD. The sensor behaviour of BMIM with Zn2+ ions were recorded by absorption and fluorescence spectra. Further, BMIM showed a selective detection towards both Zn2+ with an excellent enhancement in fluorescent intensity compared with other competitive metal ions. It is worth to note that even the ligand showed change in colour upon the addition of Zn2+ ions from colourless to pale yellow colour. The binding ratio between BMIM-Zn2+ complex was found to be 1:1 with octahedral geometry and limit of detection (LOD) was found to be 0.47 × 10−6 M.