An Azo Dye Based D‐π‐A Chromogenic Probe for Selective Naked‐Eye Detection of Hg²⁺ Ion: Application in Logic Gate Operation

Abstract

The current work describes the selective colorimetric detection of metal ions using a simple azo dye (L1) containing donor-πacceptor framework. In this chromogenic probe, salicylaldehyde is used as donor and nitrobenzene group as acceptor unit. L1 is found to show selective recognition of mercuric ion both visually and spectrophotometrically with no interference from environmentally relevant metal ions in DMSO-water mixture. It exhibits reddish-pink colour in DMSO-water medium as a result of intramolecular charge transfer (ICT) from the electron donating phenolic group to electron withdrawing nitrobenzene group. It selectively binds with Hg 2 + even in presence of other interfering metal ions and form a 1 : 1 L1-Hg 2 + adduct. It is evident from a change in colour along with a decrease of ICT absorption band and hypsochromic shift of ππ* band. The binding of the chemosensor and mercuric ion through the salicylaldehyde unit is proved from 1 H-NMR data and DFT calculations. Using UV-Vis spectroscopic technique the detection limit and binding constant values are calculated to be 6 μM and 3.3 x 10 3 M À 1 respectively. Hg 2 + probing process displays reversibility upon addition of fluoride ion. The on-offon colorimetric change on sequential addition of Hg 2 + and F À mimics an IMPLICATION type logic gate.

Polyether Sulfone-Based Organic Nanoparticle Coupled Membrane for Detection and Purification of Amoxicillin Antibiotic from Wastewater

“…The chromophoric moiety on the receptor R1 exhibits a strong push−pull π electron system with the nitro group as the acceptor and phenolic oxygen atom as the donor at the end of the azo benzene network. 29 Therefore, the chromophore displays strong intramolecular charge transfer phenomena (ICT) with eminent color due to extensive π electron conjugation. However, the ICT band disappeared after the addition of the Co 2+ metal ion.…”

Mercury Toxicity and Detection Using Chromo-Fluorogenic Chemosensors

“…The complex formation between sensor 89 and Hg 2+ restricted the ICT that caused blue-shift in absorbance, and the solution become colorless. Sensor 89 formed complex with Hg 2+ in 1:1 stoichiometric through the salicylaldehyde unit and the complexation reversed with the addition of F - [ 114 ].…”

Synthesis, Characterization, and Photophysical Probing Interaction Studies on Azo‐Sulfonamides Acting as Potent Anti‐Tubercular Agents

“…In order to detect hazardous agents, azo molecules had outstanding chromogenic and fluorogenic behaviour toward a variety of cations (Cu + 2 , Fe + 2, and Hg + 2 ), anions (CN À , AcO À ), nitric oxide (NO) and picric acid (TNP), etc. [25][26][27][28][29][30][31] In continuation of our research endeavors and the literature, a survey revealed that less work has been done in the synthesis and in exploring the biological potentialities of mono-azo sulfonamide molecules. Keeping the above facts in mind, we have synthesized a series of sulfonamide mono-azo (À N=NÀ ) bonded molecules (T 1 -T 4 ), by reacting sulfamethizole with various coupling components such as-diphenylamine (DPA), N, N-dimethylaniline (DMA), 3-diethylaminophenol (3DEAP) and 2hydroxy-1,4-naphthoquinone (2H14NQ) under the suitable experimental conditions.…”

“…The environment and human health are harmed by some ions produced by industries and chemical warfare weapons like sarin, soman, and tabun that come from degradation products (hydrolysis). In order to detect hazardous agents, azo molecules had outstanding chromogenic and fluorogenic behaviour toward a variety of cations (Cu +2 , Fe +2, and Hg +2 ), anions (CN − , AcO − ), nitric oxide (NO) and picric acid (TNP), etc [25–31] …”