| Autor: |
Joseph S; Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632 014, Tamil Nadu, India. ashokkumar.sk@vit.ac.in., Somkuwar P; Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632 014, Tamil Nadu, India. ashokkumar.sk@vit.ac.in., Menon GG; Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632 014, Tamil Nadu, India. ashokkumar.sk@vit.ac.in., Rajesh AC; Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632 014, Tamil Nadu, India. ashokkumar.sk@vit.ac.in., Selvam P; Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632 014, Tamil Nadu, India. ashokkumar.sk@vit.ac.in., Ramasamy SK; Department of Chemistry, M. M. Engineering College, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala-33207, Haryana, India., Bhaskar R; Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632 014, Tamil Nadu, India. ashokkumar.sk@vit.ac.in., Kumar SKA; Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632 014, Tamil Nadu, India. ashokkumar.sk@vit.ac.in. |
| Abstrakt: |
In this study, we present three different approaches for the colorimetric detection of Ni 2+ ions using a specifically designed benzothiazole-quinoline dyad (L) synthesized via the Knoevenagel condensation reaction in high yield. The unique properties of L enable a rapid and selective response to Ni 2+ ions, making it an ideal probe for practical applications. The probe L shows a pale yellow color under normal conditions. Upon interaction with Ni 2+ ions, L undergoes a significant color change from pale yellow to bright orange, allowing for visual detection in semi-aqueous media. This rapid colorimetric response enables real-time monitoring of Ni 2+ concentrations. The absorption maximum of L undergoes a bathochromic shift in the presence of Ni 2+ ions due to ligand-to-metal charge transfer (LMCT). The probe L could form a 2 : 1 [L : Ni 2+ ] stoichiometric complex, confirmed through Job's plot and ESI mass analysis with an estimated association constant of 2.61 × 10 6 M -2 . The probe L could detect Ni 2+ concentration down to 61 nM, 106 nM, and 129 nM via a UV-Vis spectrophotometer, smartphone-assisted RGB method, and test paper strip analysis. The binding mechanism of probe L with metal ions was studied using 1 H NMR, ESI mass spectrometry, and DFT calculations. The zeta potential analysis showed a potential of -28.38 mV for the free ligand and +12.09 mV upon complexation with Ni 2+ . More importantly, the potential application of probe L includes the quantification of Ni 2+ ions in various water samples through all three sensing approaches. |
