80571-75-1Relevant articles and documents
Selective smartphone aided colorimetric detection of Hg(II) in an aqueous solution via metal ion-induced keto-enol tautomerism–Spectroscopic and theoretical studies
Elango, Kuppanagounder P.,Nandhini, C.,Saravana Kumar, P.,Shanmugapriya, R.,Vennila, K. N.
, (2021/08/03)
A simple Schiff base-based probe (CNB) is synthesized, characterized and explored as a naked eye visual detection colorimetric probe for Hg(II) ion in an aqueous solution. Upon adding a series of cations to CNB, only Hg(II) resulted in an instantaneous colour change from pale yellow to red-orange (bathochromic shift from 348 to 392 nm). 1H NMR results suggest a relatively new Hg(II) assisted keto-enol tautomerism phenomenon in the probe followed by the enol –OH coordination with the metal ion after deprotonation. CNB forms a 1:1 Hg(II) complex with high selectivity and sensitivity, high binding constant (5×106 M?1), and an acceptable limit of detection (7 μM). The resultant CNB-Hg(II) complex has been characterized using FT-IR, 1H NMR and HR-MS spectral techniques. The electronic spectra of CNB and its Hg(II) complex are explored using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) methods. The results indicate that the energy of S0→S1 transition decreases (0.58 eV) after the complex formation, responsible for the bathochromic shift observed upon addition of Hg(II) to CNB. The practical utility of CNB to quantify Hg(II) in natural water samples is successfully confirmed using a smartphone.
