Presence Of Fe3 Research Articles

Investigation of photoluminescence properties of a DPA functionalized tris-cyclometalated iridium complex and its potential for metal sensing

Herein we report the synthesis and investigation of properties of a luminescent tris-cyclometalated complex [Ir(ppy)2ppy-dpa] (1), derived from fac-[Ir(ppy)3]. The complex carries a dipicolylamine (dpa) chelator on one of the 2-phenylpyridine (ppy) ligands. The dpa chelator exhibits minimal effect on the photophysical properties of the core iridium luminophore. The complex exhibits bright photoluminescence, which can be elicited with single photon and two-photon excitation. The two-photon excitation is achieved with light in the NIR region. Aggregation in aqueous solution has an effect on the photoluminescence properties of complex 1. The emission of complex 1 is quenched nearly completely in the presence of Cu2+ ions with a detection limit of 3.5 × 10−7 M. The luminescence of iridium complex 1 is unaffected by the presence of Co3+ and Zn2+. However, the emission of complex 1 is moderately quenched in the presence of Mn2+ and Fe2+ ions, and greatly quenched in the presence of Fe3+, Co2+, and Ni2+. However, Cu2+ causes its effect even when these competing cations are present. Complex 1 exhibits low cytotoxicity towards HeLa cells and can be imaged with single photon excitation at 405 nm or two-photon excitation at 800 nm.

N-doped carbon dots for the determination of Al3+ and Fe3+ using aggregation-induced emission.

New portable hydrogel sensors for Al3+ and Fe3+ detection were designed based on the aggregation-induced emission (AIE) and color change of N-doped carbon dots (N-CDs). N-CDs with yellow fluorescence were prepared by a one-pot hydrothermal method from 2,5-dihydroxyterephthalic acid and acrylamide. The fluorescence of N-CDs was enhanced by Al3+ about 20 times and quenched by Fe3+. It was interesting that although Fe3+ showed obvious quenching on the fluorescence of N-CDs it did not cause a noticeable change in the fluorescence of N-CDs + Al3+. The colorless solution of N-CDs appeared blue in the presence of Fe3+ without the influence of Al3+. Therefore, the turn-on fluorometry and colorimetry systems based on N-CDs were constructed for the simultaneous detection of Al3+ and Fe3+. Furthermore, the portable sensing of Al3+ and Fe3+ was realized with the assistance of hydrogel, filter paper, cellulose acetate, and cellulose nitrate film. The proposed approach was successfully applied to the detection of Al3+ and Fe3+ in food samples and cell imaging.

A PEDOT enhanced covalent organic framework (COF) fluorescent probe for in vivo detection and imaging of Fe3+

Simple and accurate in vivo monitoring of Fe3+ is essential for gaining a better understanding of its role in physiological and pathological processes. A novel fluorescent probe was synthesized via in situ solid-state polymerization of 3,4-ethylenedioxythiophene (PEDOT) in the pore channels of a covalent organic framework (COF). The PEDOT@COF fluorescent probe exhibited an absolute quantum yield (QY) 3 times higher than COF. In the presence of Fe3+ the PEDOT@COF 475 nm fluorescence emission, 365 nm excitation, is quenched within 180 s. Fluorescence quenching is linear with Fe3+ in the concentration range of 0–960 μM, with a detection limit of 0.82 μM. The fluorescence quenching mechanism was attributed to inner filter effect (IEF), photoinduced electron transfer (PET) and static quenching (SQE) between PEDOT@COF and Fe3+. A paper strip-based detector was designed to facilitate practical applicability, and the PEDOT@COF probe successfully applied to fluorescence imaging of Fe3+ levels in vivo. This work details a tool of great promise for enabling detailed investigations into the role of Fe3+ in physiological and pathological diseases.

A highly specific colorimetric and fluorometric sensor for ClO− and Fe3+ based on a pyrene derivative

In this study, a pyrene-based amphiphilic molecule (Pmvb) was designed and synthesized, which could self-assemble into rod-like aggregates in aqueous solution. The modification of luminescence and the sensing capabilities of Pmvb can be accomplished by ClO− and Fe3+ in water and DMSO, respectively, through self-assembly and disassembly process. In the aqueous solution, ClO− has the potential to engage in electrostatic interactions with the positively charged methylpyridine groups of Pmvb, which leads to a notable enhancement in fluorescence emission and a discernible alteration in color, transitioning from dark yellow to bright orange. Interestingly, in DMSO solution, the luminescence suppression of Pmvb in the presence of Fe3+ was observed, accompanied with change of the fluorescence emission color from bright yellow to dark orange, caused by the cation-π interactions between Fe3+ and the pyrene unit of Pmvb. Thus, the specific colorimetric and fluorometric sensor of pyrene derivatives could be achieved by ClO− and Fe3+ in different solvents.

Transformation of medical plastic waste to valuable carbon dots: A sustainable recycling of medical waste to efficient fluorescent marker

The dumped medical waste including disposable syringes, gloves and face masks is one of the primary responsible factors causing environmental threats and escalating landfills and CO2 discharges. Thus transforming these medical wastes into worthy carbon-based nanomaterials has offered an effective option for sustainable recycling of medical waste to efficient fluorescent markers. The current work utilizes disposable syringes, gloves and face masks as precursor sources to produce three different types of carbon dots (CDs) by using a simple heating method. The prepared CDs from three different sources have displayed considerable variations in the optical and luminescence properties of CDs. The supremacy of the prepared particles on biocompatibility parameters and the relationships between precursor source and concentration of formed CDs are also discussed via studying the antioxidant and seed germination assay. The outlook of controllable up cycled medical waste derived CDs has further been tested to develop selective and sensitive turn-off sensor for the detection of iron (Fe3+) ions. The corresponding quenching behavior in the presence of Fe3+ ions has further been explored by carrying out the optical and emission as a function of concentration and interference studies. The linear ranges for Fe3+ detection were 50 μM to 30 nM with a limit of detection down to 0.80 nM, 0.42 nM and 0.29 nM for F@CDs, S@CDs and G@CDs generated from face masks, syringes and gloves respectively. This current work presents an effective alternative to the discovery of efficient methodologies for converting disposable medical waste for environmental remediation applications and progressive conclusions for accomplishing lucrative means to manage medical waste to value added products.

Modulation of Fe–MOF via second-transition metal ion doping (Ti, Mn, Zn, Cu) for efficient visible-light driven CO2 reduction to CH4

This study developed metal–organic frameworks (MOFs) with enhanced properties for CO2 conversion by doping second- transition metal ions (Ti, Mn, Zn, and Cu) into Fe–MOF, which resulted in Fe-M−MOF (M = Ti, Mn, Zn, or Cu). The selection of different metal species in the metal cluster nodes of the MOFs significantly impacted the CO2 conversion efficiency. Among the different combinations, the Fe–Cu bimetallic cluster node was identified as the most optimal node. In addition, we investigated various variables and preparation conditions for determining the optimal synthesis conditions for Fe–Cu-MOFs. We observed that a synthesis temperature, time, and pH of 130 °C, 15 h, and 3.2, respectively, yielded the best results. The 13CO2 isotope labeling method confirmed that the carbon source of CO and CH4 were derived from CO2. Under simulated visible-light irradiation (λ ≥ 420 nm), Fe–Cu-T130 exhibited the highest photocatalytic activity, with a CH4 generation rate of up to 444.2 μmol g−1 h−1. This high activity was attributed to several factors. First, the presence of Fe2+, Fe3+, and Cu2+ on the surface of Fe–Cu-T130 resulted in photogenerated electrons and holes under visible-light excitation. Fe2+ accepted electrons to reduce CO2, whereas Fe3+ and Cu2+ oxidized H2O through holes. Second, the polycrystalline structure of Fe–Cu-T130 with abundant surface oxygen vacancies enhanced the chemical reactivity. Finally, the low conduction band position and narrower bandgap of Fe–Cu-T130 facilitated the excitation of electrons into the conduction band, thereby promoting the CO2 reduction reaction. This study successfully demonstrated the enhanced photocatalytic activity of Fe–Cu-T130 for CO2 conversion under visible light. The findings provide insight into the development of MOFs with improved properties for the sustainable and efficient utilization of CO2.

Effect of Mn2+ substitution on catalytic properties of Fe3-xMnxO4 nanoparticles synthesized via co-precipitation method

Mn-substituted magnetite samples Fe3-xMnxO4 (x = 0.0; 0.02; 0.05; 0.1; 0.15; 0.2; 0.25) were synthesized using the co-precipitation method. X-ray diffraction patterns confirmed the formation of pure, well-crystallized manganese ferrite with a cubic spinel structure. The crystallites size increases sharply for the minimum degrees of substitution, with a subsequent tendency to decrease with the growth of manganese ions content. The catalytic properties of Fe3-xMnxO4 were investigated for the degradation of oxytetracycline (ОТС) and inactivate E. coli. There is a correlation between particle size and catalytic activity. The Fe2.95Mn0.05O4 sample exhibited the highest catalytic activity in the destruction of OTC. The effect of electromagnetic heating (EMH) on the catalytic properties of iron oxides were investigated. The Fe2.9Mn0.1O4 sample with electromagnetic heating achieved 100 % efficiency in decomposing 5 mg/L of OTC. Fe3-xMnxO4 samples reduce the number of Gram-negative bacteria E. coli at concentrations of 104 and 106 CFU/mL. Electromagnetic heating experiments demonstrated high performance, achieving inactivation of 6 logs of E. coli in the presence of Fe2.98Mn0.02O4 and Fe2.95Mn0.05O4 catalysts within 135 minutes. Studies on ecotoxicity have shown that Daphnia magna is a sensitive bioindicator of residual H2O2 concentration. An increase in the Mn2+ content in the synthesized catalysts resulted in a decrease in the toxicity of purified water. The study suggests that Mn-substituted magnetite catalysts are effective materials for catalytic decomposition of OTC and inactivation of E. coli bacteria.

Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La3+-modified M-type hexaferrite with Al3+ doping

The demand for effective microwave-absorbing materials has recently surged due to rapid advancements in electromagnetic (EM) devices. Recently, engineering oxygen vacancies has also become one of the effective ways to develop efficient microwave-absorbing materials. So, understanding the EM absorption mechanism of these materials has become crucial for better engineering of such materials. This article investigates the magnetic properties along with the EM absorption mechanism of M-type hexaferrite, with optimal incorporation of rare-earth element La3+ and doping of transition metal Al3+ cation. The presence of La3+ ions at an optimal level promotes the reduction of Fe3+ to Fe2+ cations and creating oxygen vacancies to offset the electrical charge imbalance. This phenomenon impacts both the magnetic and EM characteristics of the materials. The presence of Fe2+ cations enhanced the spin-orbital interaction, resulting in a strong magnetic anisotropy field along the c-axis. The lowest reflection loss of −36.37 dB at 14.19 GHz, is observed with a bandwidth of 3.61 GHz below −10 dB for x = 0.6. These microwave absorption properties can be attributed to the adequate compensation between dielectric and magnetic losses, which arise from phenomena like dielectric relaxation, magnetic resonance, and conduction loss due to electron hopping between Fe3+ and Fe2+ with proper incorporation of the attenuating constant and excellent impedance matching, along with microstructure of the materials. Furthermore, the material’s exceptional absorption properties are also influenced by the rapid movement of oxygen vacancies from its interior to its surface when exposed to high frequencies, thereby impacting its conductivity. Therefore, it is believed that the regulation of oxygen vacancies can serve as a versatile strategy for developing materials with efficient microwave-absorbing capabilities.

A carbon quantum dot based on tetramethyl substituted cucurbit[6]uril and 2,7-dihydroxynaphthalene: Selective detection of Fe3+, ClO−and I−

Carbon quantum dots have attracted much attention as novel nanomaterials. In this study, TMeQ[6]-CQDs were synthesized by a conventional hydrothermal method using symmetric tetramethyl-substituted cucurbit[6]uril (TMeQ[6]) and 2,7-dihydroxynaphthalene (DHN) as carbon precursors, which characterized by 1H NMR, UV–vis, FL, SEM, FTIR, and XPS. Futhermore, the crystal structure was determined using Single crystal X-ray crystallography, demonstrating the formation of TMeQ[6]-based supramolecular assemblies (TMeQ[6]-DHN-[CdCl4]2−). The prepared TMeQ[6]-CQDs have abundant oxygen-containing groups with excellent water-solubility and fluorescence properties. Subsequently, using the obtained TMeQ[6]-CQDs, a universal fluorescent probe was prepared for detecting and recognizing Fe3+, I−, and ClO−. In the presence of Fe3+and I− ions, the fluorescent CQDs are quenched. Interestingly, the fluorescence spectral line undergoes a red-shift when interacting with ClO−. The detection limits were 0.41 μM, 3.71 μM and 0.10 μM.

Visible light-mediated activation of periodate for bisphenol A degradation in the presence of Fe3+ and gallic acid at neutral pH

The current study demonstrates, for the first time, the effectiveness of an innovative visible light (VL) photo-Fenton like system using periodate (PI) mediated by Fe3+ and gallic acid (GA) for bisphenol A (BPA) elimination at neutral pH. The promotion of VL irradiation and GA on the Fe2+/Fe3+ cycle in the system allowed the VL/GA/Fe3+/PI system to exhibit excellent performance for BPA removal. Complete degradation of BPA was carried out in the VL/GA/Fe3+/PI process after 30 min reaction under the optimum conditions (0.10 mM Fe3+, 0.10 mM GA, 1 mM PI, and initial pH 7.0). Electron paramagnetic resonance analysis and quenching tests confirmed that the singlet oxygen, iodate radical, and hydroxyl radical were primarily involved in the elimination of BPA with minor contribution from superoxide anion radical and high-valent iron species (Fe4+ and Fe5+). BPA abatement was slightly inhibited by the addition of Cl−, NO3−, and SO42−, whereas the addition of HCO3− obviously hindered this process. Notably, Huimic acid dramatically expedited BPA decomposition. Besides, the VL/GA/Fe3+/PI process demonstrated remarkable removal efficiency over a broad range of initial pH values (3.01–8.97). Meanwhile, based on the eight identified intermediates, the possible degradation pathways of BPA were predicted. The phytotoxicity test concluded that a decrease in toxicity of the degraded intermediates to the growth of radish seed compared to BPA. In addition, the VL/GA/Fe3+/PI system demonstrated favorable potential for application in different actual water matrices. Moreover, efficient and simultaneous abatement of various organic contaminants by the GA/Fe3+/PI process was success accomplished under natural solar light or VL. Consequently, all results implied that the VL/GA/Fe3+/PI process might be a perspective technique for the treatment of organic contaminants.

Nanoarchitectonics of Melia Dubia flowers to fluorescent carbon dots and its Ferritin sensing

In this study, the Melia Dubia flowers was utilized as a precursor for the synthesis of fluorescent carbon nanomaterial by hydrothermal method. As synthesized carbon nanomaterial have been extensively characterized and demonstrated notable characteristics, including a particle size ranging from 10 to 20 nm and excitation dependent fluorescence. Intriguingly, the carbon nanomaterial exhibited remarkable sensitivity, as demonstrated by detection limit of 23 nM for Fe3+ ions. By taking advantage of time-resolved fluorescence quenching experiments, we have satisfactorily elucidated the sensing process. The observation of a decrease in fluorescence decay in the presence of Fe3+ provides direct evidence and substantiates the occurrence of an electron transfer quenching mechanism. In addition, the selectivity of CDs has been used to detect Fe3+ in ferritin (non-heme metalloprotein). The current investigation demonstrates that Melia Dubia flowers can be utilized to develop inexpensive CDs that could serve as a fluorescent probe for the sensitive and selective detection of Fe3+ ions and Ferritin.

Synergistic activation of persulfate by manganese sulfide and Fe2+: Roles of Fe and enhancement mechanisms

Manganese sulfide (MnS) has been considered as a persulfate (PS) activator due to the presence of manganese and sulfur elements. Manganese sulfide (MnS) has been considered as a persulfate (PS) activator due to the presence of manganese and sulfur elements. However, the water solubility and hydrophobicity of MnS result in inefficient PS activation. Herein, we demonstrated that the MnS/PS system was significantly efficient for the degradation of phenol in the presence of Fe2+. Within the MnS/PS system, the Fe2+/Fe3+ cycle could act as a station to facilitate the transfer of electrons from Mn2+ and S2- to PS, thereby enhancing electron transfer efficiency. As a result, the degradation efficiency of phenol reached 91.38% within 30 min in the Fe2+/ MnS/PS system, but the MnS/PS system without Fe2+ was only 61.63%, and the reaction rate of the former was 2.52 times that of the latter. In addition, the effects of different conditions on phenol degradation were investigated, including MnS, Fe2+, PS, phenol, initial solution pH, inorganic anions. Quenching experiment and electron paramagnetic resonance (EPR) confirmed that sulfate radical, hydroxyl radical and singlet oxygen were the main active substances in the degradation of phenol. This study provides a promising idea for application in the advanced treatment of groundwater and wastewater at the end of flocculation treatment with high background iron ions.

Addressing the issue of surface mechanisms and competitive effects in Cr(VI) reductive-adsorption on tin-hydroxyapatite in the presence of co-ions

Our group recently proposed an innovative sustainable reductant-adsorbent material, tin(II)-hydroxyapatite (Sn/HAP, ca. 10 wt% Sn) for the interfacial Cr(VI) reductive adsorption process. In this study, Cr(VI) removal capacity was evaluated in multi-component solutions containing representative background ions (i.e., CaCl2, Ca(NO3)2, MgSO4, Na2SO4, Fe(NO3)3, AlCl3, Zn(NO3)2, or Mn(NO3)2). Sn/HAP was able to reduce Cr(VI) with complete Cr3+ adsorption on HAP surface, except in the presence of Fe3+ and Al3+ ions. Some metal ions co-existing in solution, such as Fe3+, Al3+, Zn2+, and Mn2+, were also adsorbed on HAP surface. Reuse experiments of the Sn/HAP sample, up to 7 runs, resulted in a total amount of reduced Cr(VI) of ca. 15–18 mg g−1. Fast kinetics of Cr(VI) reductive adsorption at 25 °C in a multi-metal component solution was observed. The pseudo-second order model was in excellent agreement with the experimental kinetic data, leading to a rate constant (k25°C) value of ca. 30 M−1 s−1. The collection of adsorption isotherms of Cr3+ and Fe3+, together with TEM–EDX analysis permitted the unveiling of competitive adsorption phenomena between metal ions. The obtained results demonstrate that Sn/HAP could be an efficient material for the removal of hexavalent chromium in aqueous solutions containing high concentrations of inorganic impurities.

Long rod-shaped gallium composite material: Self-separating material aggregation induced enhancement of ROS for photothermal/photodynamic therapy of HCT116 cells

As many of the disadvantages of traditional single therapy can be avoided with combination therapy, combination therapy has become a new treatment method. Herein, a long rod-shaped gallium composite multifunctional material (CP–Au-PEG-FA@BSA@IR780) based on chemotherapy therapy (CT), photothermal therapy (PTT) and photodynamic therapy (PDT) is constructed to increase reactive oxygen species (ROS) levels and Au NP release. CP-Au-PEG-FA@BSA@IR780 has fluorescence localization characteristics and can combine with CT-DNA to cause cancer cell apoptosis. The in vitro cytotoxicity experiments showed the excellent biocompatibility and great therapeutic efficacy of the designed nanoplatform compared to those of the IR780 group, which had weak red fluorescence. The in vivo experiments also showed that the designed micro/nano platform can effectively eliminate HCT116 tumors by allowing the temperature of the tumor site to exceed 55 °C (thermal ablation) under light irradiation. The main mechanism of chemotherapy indicated that the presence of Fe2+/Fe3+ can disrupt the rod-shaped structure of the original material and increase the content of Ga3+. Overall, CP-Au-PEG-FA@BSA@IR780 is a promising cancer therapy strategy that combines CT, PTT, and PDT and provides new insights into the synthesis method of enhancing composite materials with photothermal properties.

UV photocatalytic remediation of Methyl Red in aqueous medium by sulfate (SO4•-) and hydroxyl (•OH) radicals in the presence of Fe2+and Co@TiO2 NPs photocatalysts

Metal doping is an efficient approach to improve the performance of photocatalysts, and few attempts have been made to apply mixed metals as dopants. In this work, the decomposition of methyl red (MR) was investigated using UV/peroxymonosulfate (PMS)/Fe2+ (homogeneous) and UV/PMS/Co@TiO2 NPs (heterogeneous) advanced oxidation process (AOP) systems. The Co@TiO2 NPs for UV/PMS/Co@TiO2 nanoparticle (NPs) system was prepared by a simple reduction method. The prepared samples were characterized by transmission electron microscopy (TEM), Fourier transformer infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The small peak at 38° (004) angle indicates the presence of cobalt. The peak increased with the increase in cobalt concentration. The doped Co-TiO2 showed larger particle size due to the greater ionic radius of Co (0.74 Å) than TiO2 (0.60 Å). The photocatalytic efficiency of the catalysts was evaluated by degradation of methyl red (MR) at a wavelength of 503 nm under UV irradiation. The results showed that Co/TiO2 photocatalyst containing (0.015 g) exhibited the highest removal efficiency of 20% for adsorption of MR after 1 h in the dark. Subsequently, superior photocatalytic activity for the degradation of MR, with 99% removed after 18 min was demonstrated. The Kapp (rate constant) was found to be approximately 5.554 min−1. It was determined that the synthesized Co@TiO2 NPs remained stable during the photocatalytic reaction which could be used repeatedly with excellent degradation efficiency, hence, exposing their promising application in the treatment of wastewater. The mineralization of methyl red was confirmed by total organic carbon (TOC) analysis. The results will be useful for future enhancement of active heterogeneous photo-Fenton catalysts for developing organic dye-containing wastewater handling procedures.

Application of positively charged red mud-based carriers for anaerobic ammonium oxidizing bacteria biofilm formation

Enrichment of anaerobic ammonium oxidizing bacteria (AnAOB) in the anaerobic ammonium oxidation (anammox) process remains a challenge in engineering applications. In this study, for faster enrichment of AnAOB, red mud-based carriers were positively charged with FeCl3 and microbial promoters. The experimental results showed that the average nitrogen removal rates of the red mud-based carriers (RMGA), FeCl3-modified red mud-based carriers (RMGA-Fe), and microbial promoter-modified red mud-based carriers (RMGA-MA) increased by 24.4%–175% compared with the commercially available K3 carriers. Combining the results of SEM and laser confocal microscope, electrostatic attraction played a leading role on loading AnAOB. The increase in the surface roughness and specific area of the carriers after the attachment and the presence of Fe2+, Ca2+, and Mg2+ plasma were necessary for the subsequent growth of AnAOB, while the leaching of Cr(VI) promoted the nitrogen removal effect of AnAOB.

Metal/ADP Complexes Promote Phosphorylation of Ribonucleotides.

Under enzyme catalysis, adenosine triphosphate (ATP) transfers a phosphoryl group to canonical ribonucleotide diphosphates (NDPs) to form ribonucleotide triphosphates (NTPs), the direct biosynthetic precursors to RNA. However, it remains unclear whether the phosphorylation of NDPs could have occurred in water before enzymes existed and why an adenosine derivative, rather than another canonical NTP, typically performs this function. Here, we show that adenosine diphosphate (ADP) in the presence of Fe3+ or Al3+ promotes phosphoryl transfer from acetyl phosphate to all canonical NDPs to produce their corresponding NTP in water at room temperature and in the absence of enzymes. No other NDPs were found to promote phosphorylation, giving insight into why adenosine derivatives specifically became used for this purpose in biology. The metal-ADP complexes also promote phosphoryl transfer to ribonucleoside monophosphates (NMPs) to form a mixture of the corresponding NDPs and NTPs, albeit less efficiently. This work represents a rare example in which a single nucleotide carries out a function critical to biology without enzymes. ADP-metal complexes may have played an important role in nucleotide phosphorylation in prebiotic chemistry.

Designing dynamic metal-coordinated hydrophobically associated mechanically robust and stretchable hydrogels for versatile, multifunctional applications in strain sensing, actuation and flexible supercapacitors

Combining the synergistic effect of dynamic metal–ligand cross-linking and hydrophobic association along with low density chemical cross-linking, we have developed a mechanically robust and stretchable hydrogel that was synthesized by micellar copolymerization of acrylamide (AM), maleic acid (MA) and butyl acrylate monomer. With optimized composition, this hydrogel showed ∼ 3 MPa tensile strength & ∼ 60 MPa compressive strength. The hydrogel is stretchable ∼ 7 times of its original length. These hydrogel materials are flexible and can be folded, bent, and twisted due to their high toughness (∼10 MJ m−3) and low elastic modulus (0.56 MPa). Because of the dynamic nature of metal–ligand interaction and hydrophobic association, the hydrogel showed high energy dissipation under tensile deformation and quick recovery of the dissipated energy after repeated loading and unloading. This hydrogel showed pH responsive mechanical properties. At lower pH, the mechanical strength and elastic modulus of the hydrogel deteriorated due to the dissociation of metal–ligand interaction. This concept was further used for demonstrating shape memory effect in these materials. Utilizing the colorimetric change in presence of Fe3+ and H+, the hydrogel can be used for data encryption-decryption technology. Combining with a thermoresponsive hydrogel (Poly (N-Isopropyl acrylamide)) layer, our hydrogel showed excellent thermoresponsive reversible actuation effect. Furthermore, because of its high ionic conductivity and strain dependent resistance change, the hydrogel can be used as a flexible strain sensor and as a compressible electrolyte in flexible supercapacitor devices.

Synthesis, characterization and sensing mechanism of a novel fluorescence probe for Fe(III) in semi-aqueous solution based on a Schiff base hexadentate receptor

A new acyclic Schiff base chemosensor L was synthesized by the one pot condensation reaction of 2-[3-(formyl phenoxy)2-hydroxypropoxy]benzaldehyde and 2-aminophenol in a 1:2 molar ratio and was characterized by elemental analysis, FTIR, 1H- and 13C NMR, and fluorescence spectroscopies. These studies were complemented with a thorough conformational study at the molecular mechanics and density functional theory (DFT) levels of theory to further elucidate the structure of the compound in solution. The chemosensor L displays high sensitivity and selectivity for Fe3+ in semi-aqueous (H2O-DMF, 1:1) solution, except in the presence of a significant amount of Ni2+, with the presence of Fe3+ being signaled through the total fluorescence quenching of the fluorophore when Fe3+ binds to the recognition unit. The synthesized ligand also shows high selectivity for Fe3+ compared to the metal ions Cu2+, Zn2+, Mg2+, Mn2+, Pb2+, Hg2+, Na+, Ba2+ and Cd2+, and reasonable selectivity in the presence of Ag+, Co2+ and Cr3+. The stoichiometry and structure of the complex formed between Fe3+ and the probe L were determined from a Job’s plot and DFT calculations, respectively. The complex was characterized as a high-spin 1:1 octahedral species, in which the ligand coordinates to the metal through the two ether oxygen atoms, two nitrogen atoms and two terminal hydroxyl groups. Time dependent (TD-DFT) calculations were performed to provide information on the type of mechanism causing the quenching of the fluorescence in the presence of Fe3+.

Hg(II)/Fe(III) Turn‐On Fluorescence Response of Rhodamine‐Anthracene Derivatives with Variable Diamine Chain Length

AbstractTwo rhodamine‐anthracene derivative probes (RA1 and RA2) were designed and synthesized to incorporate different lengths of diamine chains between the rhodamine and anthracene moieties. Among the 16 different metal ions tested, RA1 exhibited the highest fluorescence enhancement in response to Hg2+ with a limit of detection (LOD) of 3.76×10−7 M, while RA2 showed the greatest fluorescence enhancement in the presence of Fe3+ with the LOD of 2.41×10−7 M. Notably, RA1 effectively eliminated the interference caused by Fe3+ during Hg2+ detection, whereas RA2 successfully eliminated the interference of Hg2+ during Fe3+ determination. This response difference between the two ions holds particular importance in scenarios where both heavy metal ions coexist. Additionally, fluorescence microscopy imaging of mouse mammary cancer cells (4T1) under the influence of Fe3+ demonstrated the potential applications of the probe. This study highlights the significance of a simple molecular design approach in tailoring probe selectivity by modifying the intramolecular flexible chain length.