A highly selective colorimetric chemosensor for sequential detection of Fe 3+ and pyrophosphate in aqueous solution

Ethyl 3-aminobenzo[b]thiophene-2-carboxylate Derived Ratiometric Schiff Base Fluorescent Sensor for the Recognition of In3+ and Pb2

An ethyl 3-aminobenzo[b]thiophene-2-carboxylate derived ratiometric Schiff base fluorescent sensor R was devised and synthesized. R exhibited a highly sensitive and selective ratiometric response to In3+ in DMF/H2O tris buffer solution. R exhibited a colorimetric/fluorescent dual-channel response to In3+. More importantly, R can distinguish In3+ from Ga3+ and Al3+ in less than 5 min. R exhibited a good linear correlation with the concentration of In3+ in the 5-25 μM range and the limit of detection for In3+ was found to be 8.36 × 10-9 M. According to the job`s plot and MS spectra, R formed a complex with In3+ at 1:2 with a complexation constant of 8.24 × 109 M2. Based on Gaussian theory calculations, the response mechanism of R to In3+ can be explained by photo-induced electron transfer (PET) and intramolecular charge transfer (ICT) mechanisms. In addition, R can be used for the detection of indium in tap water with satisfactory recoveries. Meanwhile, R displayed a linear relationship to micromolar concentrations (0-50 μM) of Pb2+ and recognized Pb2+ in a ratiometric response with a detection limit of 8.3 × 10-9 M.

A Comprehensive Review on Thiophene Based Chemosensors

The recognition and sensing of various analytes in aqueous and biological systems by using fluorometric or colorimetric chemosensors possessing high selectivity and sensitivity, low cost has gained enormous attention. Furthermore, thiophene derivatives possess exceptional photophysical properties compared to other heterocycles, and therefore they can be employed in chemosensors for analyte detection. In this review, we have tried to explore the design and detection mechanism of various thiophene-based probes, practical applicability, and their advanced models (design guides), which could be thoughtful for the synthesis of new thiophene-based probes. This review provides an insight into the reported chemosensors (2008-2020) for thiophene scaffold as effective emission and absorption-based chemosensors.

A Deferasirox Derivative That Acts as a Multifaceted Platform for the Detection and Quantification of Fe3+

Here, we report that ExSO3H, a synthetically accessible, water-soluble, non-toxic derivative of the clinical iron chelator deferasirox, acts as a colorimetric chemosensor that permits the detection and quantification of Fe3+ in aqueous samples at pH 2–5. In addition, we observed that a fluorescent turn-on response was produced when this chelator was allowed to interact with human serum albumin (HSA). This fluorescence was quenched in the presence of Fe3+, thus allowing us to monitor the presence of this biologically important metal cation via two independent methods.

A new 7-diethylamino-4-hydroxycoumarin based reversible colorimetric/fluorometric probe for sequential detection of Al3+/PPi and its potential use in biodetection and bioimaging applications

A new 7-diethylamino-4-hydroxycoumarin appended acylhydrazone probe was prepared and utilized for the sequential detection of Al³⁺/PPi in a reversible off–on–off emissive manner. The various practical applications of the probe were established.

Colorimetric Metal Sensing of Fe3+ and Cr3+ and Photophysical and Electrochemical Studies Based on Benzo[4,5]thiazolo[3,2-a]pyrimidine-3-carboxylate and Its Derivatives

Benzo[4,5]thiazolo[3, 2-a]pyrimidine-3-carboxylate derivatives (4a-i) containing electron-donor and electron-acceptor groups with remarkable photophysical and electrochemical properties were synthesized. The changes in absorption properties of compound 4a in the presence of various cations were evaluated. Compound 4a can act as a colorimetric sensor for highly sensitive and selective detection of Fe³⁺ and Cr³⁺in acetonitrile solvent. Using measurements of absorbance intensity, the binding constants for the 4a + Fe³⁺ complex and 4a + Cr³⁺ complex were found to be 1.958 × 10⁸ and 1.5442 × 10⁷ M^-1 with lower detection limits of 52 and 110 nM, respectively. ¹H NMR titrations, Fourier transform infrared (FTIR) studies, electrospray ionization (ESI)-mass spectra, and Job's plots were used to verify the mechanism of the specific reaction and colorimetric sensing of 4a + Fe³⁺ and 4a + Cr³⁺. The application of compound 4a for the determination of Fe³⁺ in spiked samples of iron tablets in different environmental water samples showed a satisfactory result with good recovery.

Naphthalimide based smart sensor for CN−/Fe3+ and H2S. Synthesis and application in RAW264.7 cells and zebrafish imaging

Probe R designed as tailor-fit triple action smart chemosensor for the sequential detection of CN⁻ and Fe³⁺via colorimetric and fluorometric ‘on–off’ method and H₂S through colorimetric method in semi-aqueous conditions.