Colorimetric anion sensors based on positional effect of nitro group for recognition of biologically relevant anions in organic and aqueous medium, insight real-life application and DFT studies
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Date
2018
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Elsevier B.V.
Abstract
A new six colorimetric receptors A1-A6 were designed and synthesized, characterized by typical common spectroscopic techniques like FT-IR, UV–Visible, 1H NMR, 13C NMR and ESI-MS. The receptor A1 and A2 exhibit a significant naked-eye response towards F? and AcO? ions in DMSO. Due to presences of the NO<inf>2</inf> group at para and ortho position with extended ?-conjugation of naphthyl group carrying –OH as a binding site. Compared to receptor A2, A1 is extremely capable of detecting F? and AcO? ions present in the form of sodium salts in an aqueous medium. This is owed to the occurrence of –NO<inf>2</inf> group at para position induced in increasing the acidity of –OH proton. Consequently, it easily gets deprotonated in aqueous media. The detection limit of receptor A1 was turned out to be 0.40 and 0.35 ppm for F? and AcO? ions which is beneath WHO permission level (1.0 ppm). Receptor A1 shows a solitary property of solvatochromism in different aprotic solvents in presence of AcO? ion. Receptor A1 depicts high selectivity towards AcO? ion in DMSO: HEPES buffer (9:1, v/v). Receptor A1 proved itself for real life application by detecting anion in solution and solid state. The binding mechanism of receptor A1 with AcO? and F? ions was monitored from 1HNMR titration and DFT study. © 2017 Elsevier B.V.
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Keywords
Bins, Colorimetry, Negative ions, Nitrogen compounds, Nitrogen oxides, Salts, Sensors, Acetate, Binding mechanisms, Coloimetric, Detection limits, DFT calculation, Fluoride, Real-life applications, Spectroscopic technique, Ions, acetic acid, anion, buffer, dimethyl sulfoxide, fluoride, mouthwash, nitro derivative, organic compound, sea water, water, chemistry, color, colorimetry, conformation, infrared spectroscopy, kinetics, limit of detection, molecular model, procedures, proton nuclear magnetic resonance, quantum theory, solution and solubility, spectrofluorometry, ultraviolet spectrophotometry, Acetates, Anions, Buffers, Color, Dimethyl Sulfoxide, Fluorides, Kinetics, Limit of Detection, Models, Molecular, Molecular Conformation, Mouthwashes, Nitro Compounds, Organic Chemicals, Proton Magnetic Resonance Spectroscopy, Quantum Theory, Seawater, Solutions, Spectrometry, Fluorescence, Spectrophotometry, Ultraviolet, Spectroscopy, Fourier Transform Infrared, Water
Citation
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy, 2018, 188, , pp. 596-610