Mn Ions Research Articles

Inhibit-AND logic gate enabled versatile BoF-AgNPs as ultrasensitive and selective nanoprobe for Mn(II) ions and nanocatalyst for rapid MB decoloration

There is great interest in fabricating devices that can detect and remove water pollutants, especially heavy metal ions and dyes from wastewater, to promote sustainable water use. In this study, an extract of Borassus flabellifer leaves (BoF-LE) was used to synthesize silver nanoparticles (BoF-AgNPs), with the BoF-LE serving as a reducing and capping agent. The sensitivity and selectivity of BoF-AgNPs for Mn(II) ions were tested by comparing with the control sample and other competent metal ions. Our results showed that BoF-AgNPs are extremely sensitive and selective in detecting Mn(II) ions, with a detection limit of 0.3 ppb. HR-TEM, UV–Vis spectroscopy, and DLS investigations were used to confirm that BoF-AgNPs detect Mn(II) ions by an aggregation-based mechanism. Additionally, it was found that BoF-AgNPs are effective in rapidly decolorizing MB dye, as demonstrated by their ability to decolorize MB by 92.66% within 7 min. This study is the first to report successful synthesis of BoF-AgNPs and their two applications, which are enabled with an Inhibit-AND logic gate. Using BoF-AgNPs to detect and degrade water pollutants may promote sustainable water use.

Role of Fe supplantation in tailoring structural, electrical conductivity, and magnetic properties in La2Ni1-xFexMnO6 double perovskites

Double perovskite system La2Ni1-xFexMnO6 (x = 0, 0.2, 0.5, 0.8 & 1.0) were developed using sol-gel method. Rietveld refinement revealed monoclinic structure (ordered) along with occurrence of rhombohedral and orthorhombic structures suggesting antisite cationic disorder. Crystallite size and average grain size of samples varied between 454 and 1058 Å and 0.774–1.429 μm respectively. XPS revealed the dual oxidation states of Ni, Fe, and Mn ions. La2NiMnO6 attained the highest DC conductivity among all compositions. The increase in DC conductivity with temperature suggested the semiconducting behavior of the samples, that explained by Thermal Activation (TA) and Variable Range Hopping (VRH) conduction mechanisms. Obtained activation energy(Edc) showed increasing trend with temperature. M-H loops exhibit a ferromagnetic nature accompanied by antiferromagnetic interactions as suggested by exchange bias and partially saturated loops. La2NiMnO6 attained the highest saturation magnetization (29.81emu/g) and decreased with Fe supplantation. The possible mechanism of tuning conductivity and magnetic properties of La2Ni1-xFexMnO6 has been discussed in detail.

Synthesis of four coordination polymers with Zn(II), Cd(II), Mn(II), or Co(II) ions and their application for fluorescence sensing toward nitenpyram, imidacloprid, and vitamin B2

Four new Zn(II)-, Cd(II)-, Mn(II)-, and Co(II)-based 1D to 2D coordination polymers (CPs) were synthesized from metal salts and 1,4-di(1-imidazol-1-yl)naphthalene (DIN) ligand via the coordination reaction under hydrothermal conditions with quantitative yields, namely, [Zn(SO4)(DIN)(H2O)] (CP-1), [Cd(NO3)2(DIN)] (CP-2), [Mn(SO4)(DIN)(H2O)3] (CP-3), and [Co(NO3)2(DIN)2(H2O)4] (CP-4). The CPs were analyzed and characterized using FT-IR, Elemental Analysis, TGA, SC-XRD, and PXRD. CP-1 was selected as a model sensor for fluorescence detection, and the sensor exhibited high quenching rates at two excitation wavelengths of λex = 230 and 290 nm, and at a single emission wavelength of λem = 350 nm. At these two different excitation wavelengths, CP-1 behaved differently during the sensing of pesticides, and the highest quenching rate was achieved by the sensor for nitenpyram (λex = 230 nm) and imidacloprid (λex = 290 nm). Furthermore, during the sensing of vitamins, CP-1 encountered a strong quenching effect toward vitamin B2. During the sensing processes, the inner filter effect (for nitenpyram, imidacloprid, and vitamin B2), fluorescence resonance energy transfer (for nitenpyram, imidacloprid, and vitamin B2), and photo-induced electron transfer (for vitamin B2) were the mechanisms responsible for fluorescence quenching.

Polymer and micellar catalysis in d-fructose oxidation by imidazolium fluorochromate: A kinetic and mechanistic study

This work investigated the oxidation of d-fructose using imidazolium fluorochromate (IFC) as an oxidant and analyzed how sodium dodecyl sulfate (SDS) and polyethylene glycol (PEG-400) affected the reaction kinetics. The process exhibited a unit-order dependence on IFC, d-fructose, and perchloric acid concentration. Perchloric acid was the primary source of hydrogen ions in the reaction mixture. The stoichiometry of the reaction indicated that 3 mol of d-fructose requires 4 mol of IFC. Acrylonitrile, a radical-generating species, did not impact the reaction rate, indicating the absence of a free radical intermediate. The reaction rate decreases as the Mn (II) ions concentration increases, suggesting the involvement of Cr (IV) species in the reaction. The dielectric value of the reaction medium (D) had an inverse effect on the rate, and the outcomes were consistent with the Amis (log k1 and 1/D) and Kirkwood plots (log k1 and (D-1/2D+1)), indicating the presence of dipole-dipole interactions in the process. SDS and PEG-400 catalyzed the reaction. The reaction showed significant catalysis before reaching the critical micelle concentration (CMC). However, the observed rate constants stabilized at higher SDS concentrations exceeding the CMC. Piszkiewicz's cooperativity model was employed to describe the surfactant catalysis, while the Benesi-Hildebrand equation was utilized to explain polymer catalysis. The activation parameters are ΔH† = 44.3 ± 1.3 kJ mol−1, and ΔS† = −133.4 ± 4.3 J K−1 mol−1. The products of the reaction have been identified by spectral analysis as d-arabinoniclactone and formic acid. The formation of an ester complex followed by its decomposition was proposed as the rate-limiting step in the proposed mechanistic reaction pathway.

Pressure-induced metallization in Pb3Mn7O15

The multiferroic material Pb3Mn7O15 exhibits a high resistivity arising from the orbital electrons localized around the manganese ions, which hinders its potential applications. Previous studies indicated that the resistivity of Pb3Mn7O15 was influenced by its crystal structure and the distribution of Mn ions. Consequently, pressure-induced structural change are expected to represent a viable method for tuning the resistivity and other properties of this compound. In the present study, the pressure effect on the resistivity of Pb3Mn7O15 was investigated up to 42 GPa. Furthermore, the X-ray diffraction and Raman spectroscopy techniques, along with the density functional theory calculations were employed to study the crystal structure evolution of Pb3Mn7O15 under pressure. The results demonstrate an electronic semiconductor-metal phase transition in Pb3Mn7O15, accompanying an irreversible orthorhombic to monoclinic phase transition. Additionally, within the orthorhombic phase, an iso-structural phase transition is observed, originating from the magnetic moments collapse of manganese cations. This study provides compelling evidence that high-pressure processing can be employed to modulate the crystal structure and functional properties of multifunctional materials.

Ammonium vanadate doped by transition bivalent metal ions for high-performance zinc-ion batteries

Vanadium-based materials are considered as promising cathode materials in aqueous zinc-ion (Zn2+) batteries (AZIBs) because of their abundant valence states and adjustable ion diffusion channels. However, the slow kinetics of the Zn2+ intercalation and the instability of the layered structure during long cycle are the bottlenecks restricting their further development. In this paper, the transition bivalent manganese ions (Mn2+) are introduced into ammonium vanadate (NH4V4O10) to partly replace the NH4+ ions to prepare a high-performance AZIB cathode. After doping transition bivalent Mn2+, the interlayer spacing of NH4V4O10 is enlarged, providing a broadened channel for the diffusion of Zn2+ accordingly. The results reveal that the electrode with the optimal doping quantity has a very high discharge capacity (539.4 mAh/g at 0.2 A/g) and excellent cyclic stability (85.3 % retention of the initial capacity after 3000 cycles at 5 A/g). A highly competitive energy density of 378 Wh kg−1 at 362 W kg−1 is delivered by the corresponding AZIB. Moreover, this method is a general and effective strategy for developing high-performance AZIB cathode materials, as demonstrated by the consistent crystal structure and stable cycling properties for NH4V4O10 doped with other transition bivalent metal cations.

Dilution of helical antiferromagnetic matrix of CaMn7O12 under nonmagnetic Ga[formula omitted] doping

The work reports dilution studies on antiferromagnetic CaMn7O12. Introduction of nonmagnetic ion in an antiferromagnetic matrix changes the magnetic properties in an interesting way. The study becomes significant due to the fact that remarkable increase in magnetization is observed as a result of substitution of a few of the magnetic Mn ions with the nonmagnetic Ga ion. For 5% doping of Ga, the magnetization value becomes nearly thrice of the un-doped CaMn7O12. A sequential decrease in antiferromagnetic ordering transition temperature is also observed with increasing Ga percentage in the parent compound. The solid solubility limit of Ga in the matrix is found to be nearly 5%, above which it start showing impurity peaks. Experimental results are well complemented with the Density functional theory (DFT) based calculations. Theoretical calculations are carried out on (CaMn7O12)3 unit cell with one Ga atom doped at different Mn sites resulting around 5% doping concentration. Besides identifying the most favourable doping site for Ga, results indicate a reduction of bulk band gap and significant increase in magnetization, both of which are in agreement with the experimental results.

Revealing the atomic and electronic mechanism of human manganese superoxide dismutase product inhibition

Human manganese superoxide dismutase (MnSOD) is a crucial oxidoreductase that maintains the vitality of mitochondria by converting superoxide (O2●−) to molecular oxygen (O2) and hydrogen peroxide (H2O2) with proton-coupled electron transfers (PCETs). Human MnSOD has evolved to be highly product inhibited to limit the formation of H2O2, a freely diffusible oxidant and signaling molecule. The product-inhibited complex is thought to be composed of a peroxide (O22−) or hydroperoxide (HO2−) species bound to Mn ion and formed from an unknown PCET mechanism. PCET mechanisms of proteins are typically not known due to difficulties in detecting the protonation states of specific residues that coincide with the electronic state of the redox center. To shed light on the mechanism, we combine neutron diffraction and X-ray absorption spectroscopy of the product-bound, trivalent, and divalent states of the enzyme to reveal the positions of all the atoms, including hydrogen, and the electronic configuration of the metal ion. The data identifies the product-inhibited complex, and a PCET mechanism of inhibition is constructed.

Optical and EPR spectroscopy of manganese doped LiNaGe4O9 single crystals

The paper presents data on the study of optical absorption, photoluminescence and EPR of lithium-sodium tetragermanate crystals (LiNaGe4O9) doped with Mn ions. Optical spectra were measured in the range 11000–45000 cm−1 and temperatures 77–300 K. They are attributed to manganese in the +4 charge state. From the analysis of optical spectra, the crystal field strength Dq = 2175.2 cm−1 and Racah parameters A = 4065 cm−1, B = 813 cm−1, C = 3239 cm−1 were determined for the Mn4+ ions. The value of the Huang-Rhys factor SFHR = 17.56 indicates a strong electron-phonon interaction of the Mn4+ ion. The presence of Mn4+ ions was further confirmed by measurement of EPR spectra at microwave frequencies 8.9 and 320 GHz. EPR data show that Mn4+ ions occupy two structurally nonequivalent lattice sites with the formation of two Mn4+ centers: Mn1 and Mn2. From the angular dependences of the EPR spectra, the components of the g factor and the hyperfine interaction tensor A, the parameters of the axial D and rhombic E crystal field were determined for both centers. The axial constant D is large for both centers: 0.644 and 0.560 cm−1, respectively. Analysis of optical and EPR spectroscopic data testifies that Mn4+ ions replace the Ge4+ ions in oxygen octahedrons within the host. Structurally nonequivalent centers are attributed to manganese ions located in undistorted lattice sites (Mn1) and in sites perturbed by the LiNa antisite defect (Mn2).

Algae promotes the biogenic oxidation of Mn(II) by accelerated extracellular superoxide production

Microbial manganese (Mn) oxidation, predominantly occurs within the anaerobic-aerobic interfaces, plays an important role in environmental pollution remediation. The anaerobic-aerobic transition zones, notably riparian and lakeside zones, are hotspots for algae-bacteria interactions. Here, we adopted a Mn(II)-oxidizing bacterium Pseudomonas sp. QJX-1 to investigate the impact of algae on microbial Mn(II) oxidation and verify the underlying mechanisms. Interestingly, we achieved a remarkable enhancement in bacterial Mn(II)-oxidizing activity within the algae-bacteria co-culture, despite the inability to oxidize Mn(II) for the algae used in this study. In addition, the bacterial density almost remains constant in the presence of algal cells. Therefore, the increased Mn(II) oxidation by QJX-1 in the presence of algae cannot be due to the increased biomass. Within this co-culture system, the Mn(II) oxidation rate surged to an impressive 0.23 mg/L/h, in stark contrast to 0.02 mg/L/h recorded within pure QJX-1 system. The presence of algae could inhibit the Fe-S cluster activity of QJX-1 by the produced active substance in co-culture, and result in the acceleration of extracellular superoxide production due to the impairment of electron transfer functions located in QJX-1 cell membranes. Moreover, elevated peroxidase gene expression and heightened extracellular catalase activity not only expedited Mn(II) ions oxidation but also facilitated conversion of intermediate Mn(III) ions into microbial Mn oxides, achieved through the degradation of hydrogen peroxide. Therefore, the acceleration of extracellular superoxide production and the decomposition of hydrogen peroxide are identified as the principal mechanisms behind the observed enhancement in Mn(II) oxidation within algae-bacteria co-cultures. Our findings highlight the need to consider the effect of algae on microbial Mn(II) oxidation, which plays an important role in the environmental pollution remediation.

The Role of Ovalbumin in Manganese Homeostasis during Chick Embryogenesis: An EPR Spectroscopic Study.

Ovalbumin (OVA), a protein vital for chick embryo nutrition, hydration, and antimicrobial protection, together with other egg-white proteins, migrates to the amniotic fluid and is orally absorbed by the embryo during embryogenesis. Recently, it has been shown that for optimal eggshell quality, the hen diet can be supplemented with manganese. Although essential for embryonic development, manganese in excess causes neurotoxicity. This study investigates whether OVA may be involved in the regulation of manganese levels. The binding of Mn(II) to OVA was investigated using electron paramagnetic resonance (EPR) spectroscopy. The results show that OVA binds a maximum of two Mn(II) ions, one with slightly weaker affinity, even in a 10-fold excess, suggesting it may have a protective role from Mn(II) overload. It seems that the binding of Mn(II), or the presence of excess Mn(II), does not affect OVA's tertiary structure, as evidenced from fluorescence and UV/vis measurements. Comparative analysis with bovine and human serum albumins revealed that they exhibit higher affinities for Mn(II) than OVA, most likely due to their essentially different physiological roles. These findings suggest that OVA does not play a role in the transport and storage of manganese; however, it may be involved in embryo protection from manganese-induced toxicity.

Targeted pH-responsive biomimetic nanoparticle-mediated starvation-enhanced chemodynamic therapy combined with chemotherapy for ovarian cancer treatment

In recent years, the use of arsenic trioxide (ATO) in the context of ovarian cancer chemotherapy has attracted significant attention. However, ATO’s limited biocompatibility and the occurrence of severe toxic side effects hinder its clinical application. A nanoparticle (NP) drug delivery system using ATO as a therapeutic agent is reported in this study. Achieving a synergistic effect by combining starvation therapy, chemodynamic therapy, and chemotherapy for the treatment of ovarian cancer was the ultimate goal of this system. This nanotechnology-based drug delivery system (NDDS) introduced arsenic-manganese complexes into cancer cells, leading to the subsequent release of lethal arsenic ions (As3+) and manganese ions (Mn2+). The acidic microenvironment of the tumor facilitated this process, and MR imaging offered real-time monitoring of the ATO dose distribution. Simultaneously, to produce reactive oxygen species that induced cell death through a Fenton-like reaction, Mn2+ exploited the surplus of hydrogen peroxide (H2O2) within tumor cells. Glucose oxidase-based starvation therapy further supported this mechanism, which restored H2O2 and lowered the cellular acidity. Consequently, this approach achieved self-enhanced chemodynamic therapy. Homologous targeting of the NPs was facilitated through the use of SKOV3 cell membranes that encapsulated the NPs. Hence, the use of a multimodal NDDS that integrated ATO delivery, therapy, and monitoring exhibited superior efficacy and biocompatibility compared with the nonspecific administration of ATO. This approach presents a novel concept for the diagnosis and treatment of ovarian cancer.

Surface nickel gradient tunes anionic redox activity to stabilize cobalt-free Li-rich cathodes

Constructing a gradient structure of transition metals is promising to improve the electrochemical performance of layered oxide cathodes. However, the nickel gradient spinel layer on the surface of layer Li-rich cathodes is barely successful. Herein, we present a refining strategy of reductive gas to induce a Ni-gradient spinel layer on the surface of Li1.2Mn0.6Ni0.2O2 (LRNMO). The formed gradient spinel layer stabilizes the coordination environment at the interface and reduces oxygen loss. Moreover, the Ni gradient further maintains the reversibility of the Mn3+/Mn4+ redox couple, while the multiple valence states of Mn ions in the gradient layer enhance the electrochemical kinetics. The LRNMO with Ni-gradient spinel layer achieves an initial coulomb efficiency reaching 86.1% and maintaining an energy density of 667.9 Wh kg−1 after 200 cycles at 1 C. The surface gradient strategy is conducive to maintaining structural stability and provides support for the continued development of Li-ion batteries.

Surface Engineering Enhances Vanadium Carbide MXene-Based Nanoplatform Triggered by NIR-II for Cancer Theranostics.

Despite the advantages of high tissue penetration depth, selectivity, and non-invasiveness of photothermal therapy for cancer treatment, developing NIR-II photothermal agents with desirable photothermal performance and advanced theranostics ability remains a key challenge. Herein, a universal surface modification strategy is proposed to effectively improve the photothermal performance of vanadium carbide MXene nanosheets (L-V2C) with the removal of surface impurity ions and generation of mesopores. Subsequently, MnOx coating capable of T1-weighted magnetic resonance imaging can be in situ formed through surface redox reaction on L-V2C, and then, stable nanoplatforms (LVM-PEG) under physiological conditions can be obtained after further PEGylation. In the tumor microenvironment irradiated by NIR-II laser, multivalent Mn ions released from LVM-PEG, as a reversible electronic station, can consume the overexpression of glutathione and catalyze a Fenton-like reaction to produce ·OH, resulting in synchronous cellular oxidative damage. Efficient synergistic therapy promotes immunogenic cell death, improving tumor-related immune microenvironment and immunomodulation, and thus, LVM-PEG can demonstrate high accuracy and excellent anticancer efficiency guided by multimodal imaging. As a result, this study provides a new approach for the customization of 2D surface strategies and the study of synergistic therapy mechanisms, highlighting the application of MXene-based materials in the biomedical field.

Optical properties of meso-tetra(sulphonatophenyl) porphyrins (TPPS 4) and their Fe 3+, Mn 3+, Zn 2+ complexes with different pH values studied using by picosecond pulse trains

Applying picosecond pulse trains propagating in meso-tetra(sulphonatophenyl) porphyrins and their Fe 3+, Mn 3+, Zn 2+ complexes, we studied the nonlinear dynamics at different pH values. The pulse train at wavelength 532nm is comprised of 20 subpulses with 70ps width and 13ns spacing. We simplified the energy structures of porphyrins and metalloporphyrins to five-level models. In solving coupled rate equations and two-dimensional paraxial field, we used Crank-Nicholson numerical method to do the calculations. The results revealed that in irregular metalloporphyrins with central paramagnetic ion Mn 3+ or Fe 3+, the central ion would act as electron acceptor, which leads to charge transfer of unpaired metal electron to the porphyrin ring π conjugated system, and strengthen the spin–orbit coupling of electronic systems and weaken the transition prohibition between electronic states in porphyrins. However regular metalloporphyrins with central diamagnetic ion Zn 2+ has similar optical properties to free base porphyrins, and Zn 2+ TPPS 4 has much longer excited state lifetimes and slower intersystem crossing. In solutions, hydrogen bond would be formed to porphyrin, which can change the transitions of π electrons and thus the charge transfer can be strengthened in the porphyrin ring. In weak intensity region with linear absorption, nonprotonated porphyrins with high pH value show better optical limiting (OL) effect. Conversely in high intensity region, protonated porphyrins with low pH value show better OL effect. Besides, increasing interaction distances of porphyrins and metalloporphyrins with laser pulses is another important factor to raise the OL effects.

Effective Photogeneration of Singlet Oxygen and High Photocatalytic and Antibacterial Activities of Porous Mn-Doped ZnO-ZrO<sub>2</sub> Nanocomposites

Disperse porous Mn-doped ZnO-ZrO<sub>2</sub> nanocomposites were prepared using the facile polymer-salt method. The effect of Mn content on the crystal structure, composite morphologies, their ability to photogenate the singlet oxygen, luminescence properties, and bactericidal activities were studied. The crystal structure and morphology of these materials were investigated using XRD and SEM analysis. It was found that obtained nanocomposites consist of small (~9 nm) hexagonal ZnO and fine ZrO<sub>2</sub> crystals and the embedding of Mn ions expands the crystal cells of ZnO crystals. Photoluminescence spectra indicate the presence of different structural defects (interstitial Zn ions and oxygen vacancies in ZnO and oxygen vacancies in ZrO<sub>2</sub> crystals). Mn-doped ZnO-ZrO<sub>2</sub> nanocomposites can photogenerate singlet oxygen under visible (λ = 405 nm) irradiation. The increased power density of the exciting blue (λ = 405 nm) light significantly enhances the singlet oxygen photogeneration by prepared composites. The dependence of the intensity of singlet oxygen photogeneration by composites on the power density of exciting radiation (at its variation in the range 0.8 ÷ 1.6 W/cm<sup>2</sup>) is close to linear. Mn-doped ZnO-ZrO<sub>2</sub> composites demonstrate superior antibacterial activity against the gram-positive bacteria <em>Staphylococcus aureus ATCC 209P</em>. It was found that highly dispersed porous Mn-doped ZnO-ZrO<sub>2</sub> nanocomposites are promising for practical environmental and medical applications.

Controlled release of manganese and magnesium ions by microsphere-encapsulated hydrogel enhances cancer immunotherapy

Despite the considerable potential of immune checkpoint blockade (ICB) therapy in treating various cancer types, it faces several challenges, of which the constrained objective response rate and relatively short duration of response observed in patients with cancer are the most important. This study introduces an injectable temperature-sensitive hydrogel, Pluronic F-127 (PF-127)@MnCl2/ alginate microspheres (ALG-MS)@MgCl2, that enhances the therapeutic efficacy of programmed cell death-ligand 1 (PD-L1) in cancer cells. The hydrogel material used in this study facilitated the rapid release of a significant amount of manganese ions (Mn2+) and the gradual and sustained release of magnesium ions (Mg2+) within the tumor microenvironment. This staged release profile promotes an immune microenvironment conducive to the cytotoxicity of CD8+ T cells and natural killer cells, thereby enhancing the efficacy of ICB therapy. Furthermore, the PF-127@MnCl2/ALG-MS@MgCl2 composite hydrogel exhibits the ability to convert drug-resistant tumor (“cold tumor”) with a low PD-L1 response to a “hot tumor” with a high PD-L1 response. In summary, the PF-127@MnCl2/ALG-MS@MgCl2 hydrogel manipulates the immune microenvironment through the precise discharge of Mg2+ and Mn2+, thus, augmenting the efficacy of ICB therapy.

Controllable preparation of MnCo2O4 spinel and catalytic persulfate activation in organic wastewater treatment: Experimental and immobilized evaluation

Transitional metal oxides are excellent candidates as heterogeneous catalysts for activating persulfate towards organics degradation. In this study, MnCo2O4 spinel was successfully prepared using a solvent-free molten method. The catalytic performance was systematically investigated and MnCo2O4 powder catalyst was successfully immobilized on polyurethane (PU) membrane through electrospinning to assess its application potential. The results showed that peroxymonosulfate (0.1 ​g ​L−1) activated by MnCo2O4 (0.1 ​g ​L−1) reached 99.92 ​% degradation in 10 ​min when treating 0.04 ​g ​L−1 rhodamine B as target pollutant. The abundant oxygen vacancies formation, synergistic effect of Co and Mn ions and high electron transfer mobility are contributing to production of reactive oxygen species. Combining with quenching experiment and time-resolved EPR, the contribution of various active species was proposed, of which 1O2 exhibited the dominant role. The flowing reaction run by the MnCo2O4-PU membrane activating PMS exhibited universal degradation on different target pollutants.

Synthesis, Characterisation and Biological Evaluation of Metal Complexes from Thiosemicarbazone

A new azo schiff base ligand, together with its metal complexes,was synthesized and characterized from a thiosemicarbazid moiety. The title (E)-2-((2-hydroxy-3-((E)-(3-nitrophenyl)diazenyl)naphthalen-1-yl)methylene)hydrazine-1-carbothioamide)(HL),was synthesized by reacting((-2-hydroxy-3-((3-nitrophenyl)diazenyl) withan thiosemicabazide in a 1:1 molar ratio,HL interacted with different metal ions (Cr,Mn,Co,Ni and Cu) to from monomerci coordination complexes .Arsng of spectroscopic and analytical techniques ,including conductance studies, H1 and C13-NMR,FT-IR, electronic and mass spectroscopy,magnetic susceptibility,and elemental micro-analysis,were used to extensivety characterize these complexes.Coordinate compounds with four and six-coordinate geometries were confirmed to from based on the characterization data .

Boosted photocatalytic and electrochemical activity of hydrothermally synthesized WO3 nanoparticles co‑doped with transition elements (Mn, Co)

In this paper, undoped WO3 and (Mn, Co) co-doped WO3 nanoparticles were successfully prepared using a facile and viable hydrothermal technique and then characterized them using different complimentary techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV–visible absorption spectroscopy, photoluminescence spectroscopy, photocatalytic and cyclic voltammetry measurements. Upon (Mn, Co) co-doping, the absorption edge shifted towards a higher wavelength with respect to that of WO3 nanoparticles, and the band gap as calculated from Tauc relation was reduced from 3.30 to 2.70 eV. The reduced intensity of photoluminescence spectra indicated that the incorporation of Mn and Co ions in WO3 nanoparticles suppressed the recombination of electron-hole pairs. The photocatalytic activity of produced samples/catalysts was estimated for the removal of Rhodamine B dye under visible light irradiation. The (Mn 5 %, Co 3 %) co-doped WO3 nanoparticles showed superior photocatalytic performance compared to undoped WO3 nanoparticles, which could be due to reduction in band gap as well as reduction in recombination rate probability of photo-generated electron-hole pairs. The electrochemical performance of (Mn, Co) co-doped WO3 nanoparticles was found to be superior than that of undoped WO3 nanoparticles. The results demonstrated that (Mn 5 %, Co 3 %) co-doped WO3 nanoparticles is a promising potential candidate for practical applications in environmental remediation (dye degradation) and energy storage devices (supercapacitors).