Chromo/Fluorogenic Detection of Co(2+), Hg(2+) and Cu(2+) by the Simple Schiff Base Sensor

J Fluoresc. 2016 Jan;26(1):11-22. doi: 10.1007/s10895-015-1723-x. Epub 2015 Nov 20.

Abstract

Herein, we reported the ditriazole Schiff base derivative 1 and evaluated its photophysical properties on induction of varieties of metal ions including Na(+), Ag(+), Ni(2+), Mn(2+), Pd(2+), Co(2+), Hg(2+), Cu(2+), Pb(2+), Cd(2+), Zn(2+), Sn(2+), Fe(2+), Fe(3+), Cr(3+) and Al(3+), in order to figure out its potential as ion sensor. The ligand 1 exhibited the strong colorimetric change in the reaction solution as well as absorption spectral shifting with the concomitant appearance of well-defined isosbestic points only upon Co(2+), Hg(2+) and Cu(2+) addition corroborates its applicability as multichannel ion detector. The different extent of spectral shifting as well as unique chromogenic change in the probe solution upon Co(2+), Hg(2+) and Cu(2+) introduction can be used as the discrimination tool for these metal ions. The ligand-metal binding stoichiometry was assessed by their optical response which was further supported by the FT-IR, NMR and mass spectrometric analysis. The association constant and the detection limits of the ligand toward Co(2+), Hg(2+) and Cu(2+) ions were calculated to be 1.52 × 10(-8), 3.26 × 10(-9), 1.16 × 10(-8) and 3.87 × 10(-10), 5.47 × 10(-11), 8.91 × 10(-11) M, respectively, employing the Benesi-Hilderbrand equation and 3 σ slope(-1) methods. Furthermore, the successive addition of Co(2+), Hg(2+) and Cu(2+) induce the constant decline in the fluorescence emission signal intensity of the probe. The quenching efficiency of the probe upon metallic induction was fitted to the Stern-Volmer equation which yielded the upward curvature in case of all the three metals ions (Co(2+), Hg(2+) and Cu(2+)) when (Io/I-1) was plotted against the quencher concentration indicating the occurrence of both the dynamic and static quenching process in the system with the average Stern-Volmer quenching constant values of 9.25 × 10(-7), 1.14 × 10(-7), 1.829 × 10(-7), respectively.

Keywords: Chromogenic; Fluorescence quenching; Fluorogenic; Isosbestic points; Schiff base.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, Liquid
  • Cobalt / analysis*
  • Copper / analysis*
  • Fluorescence*
  • Fluorescent Dyes / chemical synthesis
  • Fluorescent Dyes / chemistry*
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Mercury / analysis*
  • Schiff Bases / chemical synthesis
  • Schiff Bases / chemistry
  • Spectroscopy, Fourier Transform Infrared
  • Triazoles / chemical synthesis
  • Triazoles / chemistry*

Substances

  • Fluorescent Dyes
  • Schiff Bases
  • Triazoles
  • Cobalt
  • Copper
  • Mercury