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A cyanide-bridged di-manganese carbonyl complex that photochemically reduces CO <sub/>2</sub> to CO
摘要： A cyanide-bridged di-manganese carbonyl complex that photochemically reduces CO2 to CO? Hsin-Ya Kuo, Tia S. Lee, An T. Chu, Steven E. Tignor, Gregory D. Scholes and Andrew B. Bocarsly* Manganese(I) tricarbonyl complexes such as [Mn(bpy)(CO)3L] (L = Br, or CN) are known to be electrocatalysts for CO2 reduction to CO. However, due to their rapid photodegradation under UV and visible light, these monomeric manganese complexes have not been considered as photocatalysts for CO2 reduction without the use of a photosensitizer. In this paper, we report a cyanide-bridged di-manganese complex, {[Mn(bpy)(CO)3]2(μ-CN)}ClO4, which is both electrocatalytic and photochemically active for CO2 reduction to CO. Compared to the [Mn(bpy)(CO)3CN] electrocatalyst, our CN-bridged binuclear complex is a more efficient electrocatalyst for CO2 reduction using H2O as a proton source. In addition, we report a photochemical CO2 reduction to CO using the dimanganese complex under 395 nm irradiation.
关键词： electrocatalyst,cyanide-bridged,photochemical reduction,CO2 reduction,di-manganese,photocatalyst,carbonyl complex
更新于2025-11-19 16:56:42
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Structural, photophysical and electrochemical properties of a novel cardanol-based salophen ligand and its Mn(II) complex
摘要： A new cardanol-based salophen (hpbp) ligand and its manganese complex [Mn(hpbp)] were obtained by microwave-assisted synthesis method, with yields and reaction times of 65% in 20 min and 85% in 5min, respectively. The structural features of compounds were confirmed by electronic (UV-vis and fluorescence), infrared and NMR (1H, 13C) spectroscopic techniques. The photophysical study of the ligand showed ketoenamine-enolimine tautomeric equilibrium, which was discussed based on the excited state intramolecular proton transfer (ESIPT) mechanism and was dependent on the solvent, concentration and molecular structure. The energy of the HOMO and LUMO orbitals (-5.41 and -2.12 eV, respectively), determinated by cyclic voltammetry and UV-Vis, the energy was very close to the values determined by the theoretical calculations. The studies revealed that the hpbp is a tetradentate ligand bonded to the metal ion by phenolic oxygens and by azomethine nitrogens. Therefore, this work contributes to the science of salophen compounds, in addition to stimulating the synthesis of new ligands from renewable sources for the coordination chemistry.
关键词： Cardanol-based salophen,Solvent effect,Manganese complex,Theoretical calculations
更新于2025-11-19 16:46:39
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Development of a fluorescence immunoassay for highly sensitive detection of amantadine using the nanoassembly of carbon dots and MnO2 nanosheets as the signal probe
摘要： Fluorescence immunoassays are rapid, convenient and cost-effective for the sensitive quantitation of chemical contaminants in foodstuff. In this study, a competitive fluorescence ELISA was developed for the sensitive detection of amantadine (AMD) based on the alkaline phosphatase (ALP)-triggered fluorescence "turn-on" signals. As a fluorescence substrate, carbon dots (CDs) were adsorbed onto the surface of the MnO2 nanosheets (NSs) and formed a nanoassembly of p-CDs@MnO2 NSs which results in the fluorescence quench of CDs. The ALP labelled on antibody could catalyze the hydrolysis of the 2-phospho-L-ascorbic acid into ascorbic acid. The latter could then reduce and decompose the MnO2 NSs, which was accompanied by the release of CDs from the surface of MnO2 NSs and led to the fluorescence recovery of CDs. The change of the fluorescence intensity is related to the concentration of AMD in solution and thus could be applied to detect AMD in an ALP-based ELISA system. The fluorescent ELISA showed a linear detection for AMD in the range of 0.048 ng mL?1 to 1.1 ng mL?1 with a detection limit (LOD) of 0.035 ng mL?1. The novel fluorescent ELISA shows potential for the highly sensitive detection of AMD and other analytes in food analysis.
关键词： manganese dioxide nanosheets,carbon dots,fluorescent immunoassay,amantadine
更新于2025-11-14 17:04:02
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Enzyme-free “on-off-on” photoelectrochemical biosensor based on cascaded quadratic amplification strategy for miRNA 141 detection
摘要： MicroRNAs (miRNAs) assay is of great significance for early diagnosis of diseases, so an enzyme-free “on-off-on” PEC biosensor has been developed for sensitive miRNA 141 determination. Manganese-doped cadmium sulfide coupled with zinc sulfide quantum dots (Mn:CdS@ZnS QDs) and manganese porphyrin (MnPP) have been used as photoelectric material and photosensitizer, respectively. And a high photocurrent of approximately 70.0 μA has been obtained. Cascaded quadratic amplification strategy has been applied in the system. Mn:CdS@ZnS QDs was characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX). Photoelectrochemical and electrochemical technologies were used to monitor the fabrication process of the biosensor. The sensing platform exhibits recommendable stability and good selectivity, miRNA 141 can be accurately quantified with a linear range of 1.00 × 10-14 to 1.00 × 10-8 mol·L-1 and the detection limit of 3.30 fmol·L-1. This method provides promising potential to explore sensitive detection models for various biological molecules.
关键词： Hybridization chain reaction,Catalytic hairpin assembly,Manganese-doped cadmium sulfide coupled with zinc sulfide quantum dots,MiRNA 141,Photoelectrochemistry,On-off-on
更新于2025-11-14 17:03:37
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Interesting makeover of strontium hexaferrites for environment remediation from excellent photocatalysts to outstanding adsorbents via inclusion of Mn3+ into the lattice
摘要： Manganese incorporated strontium hexaferrites with composition SrMnxFe12-xO19 (x= 0.0, 0.4, 0.8, 1.2, 1.6, 2.0, 3.0, 4.0 and 5.0) were fabricated via chemical co-precipitation methodology. Various characterization techniques were employed to investigate the physical properties of the synthesized hexaferrites. Powder X-Ray Diffraction (XRD) patterns revealed the formation of hexagonal phase with P63/mmc space group. FE-SEM micrographs exhibited hexagonal morphology of the synthesized materials; particle size of 125-150 nm range was observed. EDX spectra unveiled the presence of desired elements. The lattice interplanar fringe width from HR-TEM images was observed to be 0.22 nm, 0.26 nm and 0.27 nm indexed to (114), (107) and (203) planes of the manganese doped strontium hexaferrite. Surface area of the synthesized hexaferrites was found to be in the range of ~7.8 to ~8.4 m2/g, scrutinized by Brunauer–Emmet–Teller (BET) plots. Saturation magnetisation values were found to decrease with increase in Mn content from 38.7 to 11.7 emu/g, albeit retaining sufficient magnetic strength to be recovered using an external magnet. Absorption edge for all the hexaferrites was found to lie in the visible region of the spectrum. The oxidation state of different elements present in synthesized hexaferrites was scrutinized using X- ray Photoelectron Spectroscopy (XPS). To explore the catalytic efficiency of the synthesized hexaferrites, photo-fenton degradation of methyl orange (MO), remazol deep red (RDR) and p-nitrophenol (PNP) was employed. All the synthesized hexaferrites were found to be highly proficient, degrading the pollutants upto ~98%. Interestingly, astonishing adsorption of ~92.7 % was showcased by SrMn5Fe7O19, prior to the addition of oxidizing agent indicating the symptomatic transformation from excellent photocatalyst to outstanding adsorbents via incorporation of Mn3+ into the lattice. The maximum adsorption capacity of 56.20 and 112.35 mg/g was observed for MO and RDR, respectively.
关键词： photo-fenton degradation,strontium hexaferrites,adsorption,chemical co-precipitation method,manganese substituted ferrites
更新于2025-11-14 17:03:37
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Manganese dioxide nanoparticles/activated carbon composite as efficient UV and visible-light photocatalyst
摘要： Manganese dioxide nanoparticles/activated carbon (MnO2/AC) composites and manganese dioxide nanoparticles (MnO2 NPs) are prepared through chemical reduction method. Morphological study shows that MnO2 NPs had cylindrical and spherical shape. The morphological study also revealed that MnO2 NPs were well dispersed on AC while neat Mn NPs present both in dispersed and in agglomerated form. The FT-IR study confirms the synthesis of MnO2 NPs. Zetasizer study presented that the Mn NPs had uniform size and below 100 nm in size and had zeta potential of ? 20 mV, which represent its stability in the suspension form. The synthesized Mn/AC composite and Mn NPs were utilized as photocatalysts for the photodegradation of Congo red (CR) dye. The degradation study shows that MnO2/AC composite degraded CR dye more efficiently than MnO2 NPs under UV and normal light irradiation. The efficient degradation of dye by Mn/AC composite is due to the synergistic effect between dye adsorption on AC and rapid photodegradation by supported MnO2 NPs. The results revealed that Mn/AC composite degraded about 98.53% of CR dye within 5 min while MnO2 NPs degraded 66.57% of dye within the same irradiation time. The recycled catalyst also significantly degraded dye which verifies its sustainability. The effect of catalyst dosage and initial dye concentration was conducted. The degradation rate of dye was found drastically faster in tap water (in presence of catalyst), which might be due to the presence of various mineral ions in the tap water.
关键词： Manganese dioxide,nanoparticles,Activated carbon,Photodegradation,Photocatalyst,Congo red
更新于2025-09-23 15:23:52
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Artificial Mn4Ca-cluster with Exchangeable Solvent Molecules Mimicking the Oxygen-Evolving Center in Photosynthesis
摘要： The natural Mn4Ca-cluster in photosystem II serves as a blueprint to develop artificial water-splitting catalysts in artificial photosynthesis. Although significant advances have recently been achieved, it remains great challenges to prepare robust artificial Mn4Ca-cluster to precisely mimic the structure and function of the biological catalyst in the laboratory. Here, we report the isolation and structural characterization of two Mn4CaO4-complexes from polar solvents acetonitrile or N, N-dimethylformamide, which closely mimics the two water molecules on calcium ion, as well as, the oxidation states of the four manganese ions and the main geometric structure of the natural Mn4Ca-cluster. These new artificial Mn4Ca-complexes provide important chemical clues to understand the structure and mechanism of its biological paragon.
关键词： heterometallic complexes,photosynthesis,bioinorganic chemistry,water splitting,manganese
更新于2025-09-23 15:23:52
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Effect of operational parameters on the photocatalytic degradation of Methylene blue dye solution using manganese doped ZnO nanoparticles
摘要： Photocatalytic degradation of aqueous solution of methylene blue dye under UV light illumination was studied by using manganese doped ZnO (Zn1-xMnxO, where x = 0.00, x = 0.02 and x = 0.05) nanoparticles as a photocatalyst. The nanophotocatalysts were synthesized by wet chemical co-precipitation method. The structural, morphological, and optical properties of the photocatalysts were done by X-ray diffraction (XRD), Scanning Electron microscope (SEM), Energy Dispersive X-Ray (EDX), photoluminescence (PL), Fourier Transform Infrared Ray (FTIR) and UV- visible spectroscopic techniques. An improved photocatalytic efficiency of ZnO was observed upon doping with Mn and 2% Mn-doped ZnO exhibited the highest photocatalytic activity among the doped samples. The effect of operating parameters such as amount of catalyst, the initial dye concentration, and initial pH on the rate of dye degradation using 2% Mn-doped ZnO was studied. Under the optimum operation conditions, approximately 99% of dye removal was achieved after 120 min of irradiation.
关键词： Manganese doped ZnO,Photocatalytic activity,Methylene blue dye
更新于2025-09-23 15:23:52
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A SHG-active manganese coordination polymer with noncentrosymmetric structure based on achiral carboxyphosphinate ligand
摘要： The hydrothermal reaction of MnSO4 with the achiral 2-carboxyethyl(phenyl)phosphinate ligand (H2L) afforded a 2 D coordination polymer manganese phosphinate, [Mn(HL)2]n (1) (H2L ? 2-carboxyethyl(phenyl) phosphinic acid). It contains two types of dimeric ring motifs, which can generate a layer structure through edge-sharing. The interlayer stacking by C-H … p interactions between the C-H groups of the phenyl rings of HL- and the phenyl rings of the adjacent layers results in its crystallization in a noncentrosymmetric crystal structure with (43)2(46(cid:2)66(cid:2)83) topology. Compound 1 shows a second harmonic generation response that is 0.8 times that of urea. The luminescence spectrum indicates an emission maximum at 457 nm, attributed to an intra-ligand emission state.
关键词： noncentrosymmetric structure,manganese,coordination polymer,Hydrothermal synthesis
更新于2025-09-23 15:23:52
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A Selective Earth-Abundant System for CO <sub/>2</sub> Reduction: Comparing Photo- and Electrocatalytic Processes
摘要： The valorization of CO2 via photo- or electrocatalytic reduction constitutes a promising approach toward the sustainable production of fuels or value-added chemicals using intermittent renewable energy sources. For this purpose, molecular catalysts are generally studied independently with respect to the photo- or the electrochemical application, although a unifying approach would be much more effective with respect to the mechanistic understanding and the catalyst optimization. In this context, we present a combined photo- and electrocatalytic study of three Mn diimine catalysts, which demonstrates the synergistic interplay between the two methods. The photochemical part of our study involves the development of a catalytic system containing a heteroleptic Cu photosensitizer and the sacrificial BIH reagent. The system shows exclusive selectivity for CO generation and renders turnover numbers which are among the highest reported thus far within the group of fully earth-abundant photocatalytic systems. The electrochemical part of our investigations complements the mechanistic understanding of the photochemical process and demonstrates that in the present case the sacrificial reagent, the photosensitizer and the irradiation source can be replaced by the electrode and a weak Br?nstedt acid.
关键词： photocatalysis,electrocatalysis,manganese,copper,carbon dioxide utilization
更新于2025-09-23 15:23:52