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An ampyrone based azo dye as pH-responsive and chemo-reversible colorimetric fluorescent probe for Al3+ in semi-aqueous medium: implication towards logic gate analysis

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Abstract

A novel ampyrone based azo dye, 4-((6-hydroxybenzo[d][1,3]dioxol-5-yl)diazenyl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (1), was synthesized by coupling sesamol and 4-amino antipyrine (ampyrone) and was characterized spectroscopically. The interaction of azo dye (1) with different metal ions was studied using UV-vis and fluorescence spectra. Chemosensor 1 exhibits high selectivity and sensitivity towards Al3+ over other metal ions by fluorescence enhancement in methanol : water (1 : 1, v/v, at pH = 7.2), which could also be detected directly by the naked eye under visible light. The fluorescence of the 1–Al3+ complex was found to be reversible in the presence of EDTA. The pH-dependent absorption behavior of chemosensor 1 was also investigated. It was observed that chemosensor 1 could also be used as a selective ‘naked-eye’ colorimetric sensor for H+ and displayed a very strong red shift in the absorption band from 492 nm to 540 nm with a notable color change from yellow to violet-blue. Moreover, chemosensor 1 showed keto–enol tautomerization in the presence of acidic media and both forms were confirmed by 1H and 13C NMR spectra. Practical applicability of sensor 1 was further explored using sensing strip analysis, which enables rapid detection of Al3+ and H+ ions. NMR and DFT optimized geometries of chemosensor 1 suggest that the compound is present in the azo form (enol form) in the ground state. In addition, an INHIBIT logic gate was constructed based on the multi-responsive properties of chemosensor 1 induced by Al3+ and EDTA2−, which contained two input signals (In1: Al3+, In2: EDTA) and an output signal (O1: fluorescence intensity at 613 nm). The chemosensor 1 exhibited a high association constant with a detection limit of 3.55 × 10−7 M for Al3+ in MeOH–water solution.

Graphical abstract: An ampyrone based azo dye as pH-responsive and chemo-reversible colorimetric fluorescent probe for Al3+ in semi-aqueous medium: implication towards logic gate analysis

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Publication details

The article was received on 30 Oct 2017, accepted on 24 Dec 2017 and first published on 26 Dec 2017


Article type: Paper
DOI: 10.1039/C7NJ04194B
Citation: New J. Chem., 2018, Advance Article
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    An ampyrone based azo dye as pH-responsive and chemo-reversible colorimetric fluorescent probe for Al3+ in semi-aqueous medium: implication towards logic gate analysis

    G. Bartwal, K. Aggarwal and J. M. Khurana, New J. Chem., 2018, Advance Article , DOI: 10.1039/C7NJ04194B

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