Metallochromic Hydrazone‐Based Chemosensor with Application in a Colorimetric Paper Strip for Selective Detection of Cu²⁺

Abstract

A new tricyanofuranhydrazone‐based colorimetric chemosensor (TCFH) was synthesized and immobilized onto paper strips for selective detection of Cu2+ in aqueous environments. The synthesis strategy of TCFH involved an azo‐coupling process between the diazonium salt of 8‐aminoquinoline and an active methyl‐bearing tricyanofuran (TCF) heterocyclic moiety. Due to intramolecular charge transfer, TCFH chromophore demonstrated pronounced solvatochromism depending on the solvent polarity. Changes in both color and UV‐Vis absorption spectra demonstrated by the developed chemosensor proved that TCFH can be utilized to detect Cu2+ in the presence of other competing metallic cations and anions. The synthesized TCFH probe, which contains a hydrazone recognition moiety, demonstrates dramatic solvatochromic activity and high selectivity at the microlevel of copper ions with a color shift from yellow to purple. Moreover, test strips of TCFH were successfully developed and applied for the detection of copper ions at different concentrations in aqueous media. The colorimetric properties of the prepared TCFH‐immobilized paper strips were investigated by CIE Lab chromogenic parameters, colorimetric strength (K/S) and UV‐Vis absorbance spectra. The best detection of Cu2+ was achieved in the pH range of 6.6–7.4 demonstrating an immediate color switch relying on the total content of Cu2+. SEM was applied to characterize the deposition of tricyanofuranhydrazone onto the surface of the paper strip.

Imidazo[1,2‐a]pyridine Based D‐π‐A Fluorescent Sensor for Detection of Diethylcyanophosphonate

“…ICT-based solvatochromic fluorophores displayed micro-environment sensitive photophysical properties in terms of different colour, intensity, wavelength in absorption and emission spectra. [36,37,38] Solvatochromic fluorophore on excitation undergoes electron transfer from donor to an acceptor that causes charge distribution and brings a large change in dipole moment, resulting in solvent-dependent fluorescence behavior. [39,40]…”

Synthesis, characterization, antibacterial activity, and molecular docking of novel dicyanodihydrofuran‐based push–pull fluorophores

“…Dicyanodihydrofuran‐based push–pull fluorophores have found extensive application in areas such as nonlinear optics. [ 4–6 ] DCDHF‐based push–pull fluorophores are characterized by their superior stability, making them prime candidates for various applications such as biologically active agents, laser dyes, and for single molecule bioimaging and photovoltaics. [ 7–10 ]…”

“…Dicyanodihydrofuran-based push-pull fluorophores have found extensive application in areas such as nonlinear optics. [4][5][6] DCDHFbased push-pull fluorophores are characterized by their superior stability, making them prime candidates for various applications such as biologically active agents, laser dyes, and for single molecule bioimaging and photovoltaics. [7][8][9][10] In the current study, we describe the synthesis, characterization, antioxidant activity, and molecular docking of novel DCDHF-based push-pull fluorophores with interesting molar extinction coefficients.…”