A dual colorimetric chemosensor based on Schiff base for highly selective and simultaneous recognition of CN- and Sn2+

A new colorimetric chemosensor 2-methoxy-6-{(E)-[(4-methylphenyl)imino] methyl}-44(E)-(4-nitrophenyl) diazenyl] phenol (SZ) was designed and synthesized for simultaneous detection of CN- and Sn2+ in MeCN: bistris buffer solution. The sensor SZ showed quick and selective colorimetric response towards CN- and Sn2+ with a change in color from yellow to pink and colorless respectively without any interfering anions or cations. Meanwhile, the binding mode of SZ for CN- and Sn2+ were studied by H-1 NMR, ESI-MS, FT-IR spectroscopy, Job's plot analysis and DFT calculations. The detection limit of SZ towards CN- and Sn2+ was found to be 0.649 mu mol/L and 0.754 mu mol/L respectively which are lower than the WHO guidelines for drinking water. Furthermore, chemosensor SZ was successfully utilized as a colorimetric chemosensor for the detection of CN- and Sn2+.