Selective Recognition Of Fe3 Research Articles

Conjugated Polymer-Based Hydrogel Film for a Fast and Sensitive Detection of Fe(Ⅲ) in Vegetables.

Fluorescent film sensors are ideal for the real-time outdoor detection of heavy metal ions of Fe3+, but they are limited because of their low sensitivity and long response time due to their special structure. In this work, we constructed a fluorescent hydrogel for the specific detection of Fe3+, utilizing poly(9-fluorenecarboxylic acid) (PFCA) as the sensing moiety and sodium alginate (SA) as the cross-linking substrate, which exhibited a rapid and selective recognition of Fe3+ among a panel of 16 anions and 21 cations. It can sense Fe3+ at 0.1 nM immediately owing to the porous network structure of the PFCA-SA film that provided enhanced ion transport channels and active sites, and the "molecular line effect" of polymer PFCA. Moreover, we successfully applied this platform to detect Fe3+ in four different vegetable samples. This work provides an innovative and effective strategy for fabricating green and sustainable fluorescent sensors.

Fluorescent Determination of Ferric Ion in vitro with Carbon Quantum Dots Prepared by L-Arginine and Citric Acid

Ferric ion (Fe3+) serves as an essential and indispensable inorganic element in various biological process. Excess Fe3+ is harmful for biological systems and human health. Herein, highly sensitive carbon quantum dots (Fe-CQDs) for ferric ions were synthesized by a high-efficiency, one-step hydrothermal route utilizing L-arginine and citric acid. The prepared Fe-CQDs exhibited good water solubility, high photostability, and bright blue florescence with relatively high quantum yields (QYs) over 21.33% and a Stokes shift exceeding 100 nm. The functionalized Fe-CQDs offer rapid, sensitive, and selective recognition of Fe3+ with a linear relationship from 0.6 to 80 μM and a low detection limit of 0.2 μM. Moreover, the synthesized Fe-CQDs illustrated strong anti-interference properties in samples and buffer solutions. The developed sensor demonstrated high biocompatibility and was successfully applied for intracellular Fe3+ determination in SHSY5Y and HT22 cells, illustrating excellent imaging application. The present work provides a promising platform for the early clinical diagnosis of Fe3+-associated diseases.

Designing Nonconventional Luminescent Materials with Efficient Emission in Dilute Solutions via Modulation of Dynamic Hydrogen Bonds.

Nonconventional luminescent materials (NLMs) which do not contain traditional aromatic chromophores are of great interest due to their unique chemical structures, optical properties, and their potential applications in various areas, such as cellular imaging and chemical sensing. However, most reported NLMs show weak or no emission in dilute solutions, which severely limits their applications. In this work, dynamic hydrogen bonds were utilized to design NLMs with efficient emission in dilute solutions. To further validate the results, polymers P1 and P2 were successfully prepared and investigated. It was found that the luminescence quantum efficiency of P1 and P2 at a concentration of 0.1 mg/mL in water solution was 8.9 and 0.6%, respectively. The high efficiency can be attributed to the fact that polymer P1 has more intra- or intermolecular dynamic hydrogen bonds and other short interactions than P2 in dilute solutions, allowing P1 to achieve the through-space conjugation effect to increase the degree of system conjugation, restrict molecular motion, and decrease nonradiative transitions, which can effectively improve luminescence. In addition, polymer P2 exhibits the characteristics of clustering-triggered emission, excitation wavelength-dependent and concentration-dependent fluorescence properties, excellent photobleaching resistance, low cytotoxicity, and selective recognition of Fe3+. The present study investigates the manipulation of luminescence properties of NLMs in dilute solutions through the modulation of dynamic hydrogen bonds. This approach can serve as a semi-empirical technique for designing and building innovative NLMs in the times ahead.

A highly selective “on–off” fluorescent sensor for detection of Fe3+ ion in protein and aqueous media: Synthesis, structural characterization, and computational studies

We describe herein the design and synthesis of a smart PGA chemosensor characterized by various techniques viz., FT-IR, UV–visible, 1H NMR, 13C NMR, Mass spectroscopy, and single crystal X-ray diffraction studies. The X-ray crystal analysis revealed that the PGA chemosensor crystallized in the orthorhombic crystal system with P212121 space group. The photophysical properties of the synthesized PGA chemosensor were examined by employing absorption and fluorescence spectral analysis. PGA revealed turn-on sensing responses towards the selective recognition of Fe3+ over other metal ions via CN isomerization processes. PGA also shows reversible effects upon the addition of EDTA. The 2:1 binding stoichiometry was calculated using Job’s plot and the value of detection limit was found to be 0.265 × 10-5 M, which is far lower than the permitted limit for drinking water according to WHO guidelines. The sensing mode of PGA towards Fe3+ was explored by employing FT-IR and 1H NMR studies. Density Functional Theory (DFT) studies, were employed which closely agreed with the experimental results. The PGA chemosensor has been successfully used to detect Fe3+ in various water samples and BSA medium. Furthermore, confocal imaging studies were examined, which supports the sensing ability of PGA for detection of Fe3+ in aqueous and protein medium.

Novel water soluble polymeric sensors for the sensitive and selective recognition of Fe3+/Fe2+ in aqueous media

Fe3+ and Fe2+ are common metal ions in natural water environments and creatures. The development of water-soluble fluorescent sensors for detecting Fe2+/Fe3+ ions was of great significance. In this work, two kinds of boron fluoride dipyrrole (BODIPY) fluorescent small-molecules were synthesized firstly. One of the small molecules contains a thioester bond that can be used as a chain transfer agent to participate in the polymerization process, and the other contains an unsaturated C = C double bond at the meso position. Through the reversible addition-fragmentation chain transfer polymerization (RAFT) polymerization method, methacrylic acid (MAA) and methacrylamide (MAM) were used as the main monomers, and small molecular fluorescent monomers were introduced to the end of the main chain. In this way, fluorescent macromolecules were obtained. The polymers were water soluble owing to the presence of long enough hydrophilic carboxyl and amide chains. These fluorescent probes exhibit high sensitivity to Fe2+/Fe3+, good selectivity, and anti-interference of other ions. The detection limit for Fe2+ was as low as 2.3 × 10−7 M, and the detection limit for Fe3+ can reach up to 4.5 × 10−7 M. The results show that these probes can be used as good sensors to identify Fe2+ and Fe3+. Moreover, the fluorophores could be incorporated into polymer chains as the RAFT reagents and/or functional monomers.

Propargyl-functionalized single arm allied Anthracene based Schiff bases: Crystal structure, solvatochromism and selective recognition of Fe3+ ion

An organic moiety exhibit specific behavior in electronic absorption spectra while accommodating various solvents or metal ions and that specificity depends on particular guest solvent molecules or metal ions. Herein, we report about the photophysical properties of newly synthesized Propargyl-functionalized anthracene based Schiff bases (PASB). The formulated compounds have been thoroughly characterized by elemental analysis, FT-IR, NMR (1H and 13C) and UV-Vis spectroscopy, emphasized with Kamlet-Taft approach to explain the solvatochromic behavior of the synthesized compounds. PASBs were screened for the sensorial aptitude towards various metal ions which were found to act as an excellent UV-Vis probe for selective detection of Fe3+ ion with LOD 1.60 × 10−8M. Additionally, coordination behavior of ligand with Fe3+ ion was examined through the change in magnetic property of Fe3+ ions by VSM (vibrating sample magnetism) study. Moreover, complete structure elucidation of compound 4b was achieved via X-ray crystallography. The binding sites of sensor conjugate 4b-Fe3+ are well supported by FT-IR spectroscopy and computational analysis following DFT approach. The reported contribution focused on the factors determining the ability of propargyl appended Schiff base to present structure, mental picture of solvatochromism and metal ion sensitivity.

Supramolecular chemosensor for selective detection of iron in aqueous medium

We have successfully developed a ‘turn-on’ colorimetric chemosensor for Fe3+ based on 1,10-phenanthroline. An amide derivative of 1,10-phenanthroline 4 was developed for the selective recognition of Fe3+ over Co2+, Cr3+, Cu2+, Mn2+, Ni2+, Ag+ and Zn2+ and could measure Fe3+ concentration in the range of 15–210 μM by UV–vis spectroscopy. Moreover, the addition of Fe3+ to a colourless solution of 4 turned its colour to light pink, indicating that 4 is capable of detecting Fe3+ by the naked eye. Compound 4 exhibits a major absorption band centred at 268 which shifted to 278 nm after addition of Fe3+, and a shoulder band around 514 nm was also observed. The complexation of Fe3+ with 4 was analysed at a different pH and favourable binding was observed at pH 6.2.

Carboxylated ‘locking unit’ directed ratiometric probe design, synthesis and application in selective recognition of Fe3+/Cu2+

A ratiometric probe has been designed and synthesized through the introduction of a carboxylated functionality. The probe 1, synthesized in two steps, was found to be a fluorescent chemosensor for the selective ratiometric detection of Fe3+/Cu2+ over a wide range of metal ions quite efficiently. The carboxylated unit, ‘CH2COOH’, acts as a ‘locking unit’ restricting the possibility of E/Z isomerization and ESPT. This has been supported by theoretical studies. The selectivity was established using various spectroscopic techniques such as UV-vis and fluorescence spectroscopy. The probe was found to have fluorescence properties with a quantum yield of 0.18. The binding of this fluorescent receptor to metal ions was also proved by NMR and mass spectrometry. The present probe can efficiently detect the presence of very low concentrations of Fe3+/Cu2+ (0.51 and 4.46 μM of Cu2+ and Fe3+ respectively).