Applied Organometallic Chemistry最新文献

To enhance the CO₂ hydrogenation activity and low-carbon olefin selectivity of Fe-based catalysts, a strategy involving the use of metal promoters to modulate the structure of active metal centers in catalyst preparation was proposed. The incipient wetness impregnation method was used to introduce modifying agents K and/or Co into the Fe/Al₂O₃ catalyst. Characterization techniques such as XRD, BET, SEM, HRTEM, H₂-TPR, XPS, CO₂-TPD, NH₃-TPD, and TG were employed to investigate the effects of the modifying agents on the dispersion, reducibility, electronic properties, and acid–base properties of active metal species. Furthermore, the influence of K and Co modification on the CO₂ hydrogenation activity and low-carbon olefin selectivity of Fe/Al₂O₃ catalysts was explored. The results revealed that the introduction of K generated more basic sites and electron-rich active metal centers in the catalyst, facilitating the adsorption and activation of CO₂, while suppressing the hydrogenation of olefins and the formation of methane, thus improving the selectivity towards low-carbon olefins. Co promoter facilitated the dispersion of Fe species, exposing more active sites and enhancing the FTS reaction activity, leading to more CO being converted into C₂₊ hydrocarbon products. Under the synergistic effect of K and Co, the CO₂ conversion activity of the Fe-based catalyst significantly increased, achieving a CO₂ conversion rate of 37%, while the selectivity towards C₂-C₄₌ increased to 31.9%.

Sulfur dioxide is serious ultimatum to human health as well as environment, while carbon dioxide is viewed as one of the primary drivers of the worldwide temperature alteration. Therefore, capturing of these gases is a dynamic research subject attracting much consideration from scientists. Herein, we report synthesis of a series of Co-ZIF and bimetallic M-Co-ZIF adsorbents and application for room temperature adsorption of SO₂ and CO₂. In this work, the breakthrough curves for the adsorption of sulfur dioxide and carbon dioxide on Co-ZIF and M-Co-ZIF were obtained experimentally and theoretically using a laboratory-scale fixed bed column at room temperature. In this work, the adsorption capacities and breakthrough points for modified bimetallic M-Co-ZIF were found to be relatively higher than parent Co-ZIF. Notably, a high SO₂ uptake capacity of 7.1 mmol/g for Zr-Co-ZIF and high CO₂ uptake capacity of 69.9 mmol/g for Ni-Co-ZIF were achieved. The parent cobalt and bimetallic ZIF materials were characterized by XRD, FTIR, SEM, and nitrogen physisorption. The XRD results confirm the formation of pure phase highly crystalline ZIF materials while BET analysis suggests high surface area of prepared adsorbents. Finally, the results of dynamic adsorption combined with characterization show great potential for preparation of bimetallic ZIF adsorbents for effective SO₂ and CO₂ adsorption.

A multifunctional nanostructured hybrid composed of metal–protein–ceramic was designed and then synthesized using three different methods: chemical reduction, physical adsorption, and coprecipitation. The processes yielded colloidal spherical silver nanoparticles (AgNPs) enveloped in a bovine serum albumin (BSA) corona, leading to the core–shell structure AgNPs–BSA. To enhance biocompatibility and mitigate potential toxicity associated with metallic nanoparticles, this core–shell structure was coated with a layer of calcium carbonate (CaCO₃). In order to analyze the internal structure of the resulting hybrid nanostructure (AgNPs–BSA–CaCO₃), a number of samples were produced by focused ion beam (FIB) and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and zeta potential (ζ) measurements. The cytotoxic effect of the samples were evaluated through in vitro tests on mouse macrophage cell line RAW 264.7 ATCC TIB-71, this was accomplished by calculating the appropriate concentrations from the dose–response curve of AgNPs. Research showed that the AgNPs–BSA–CaCO₃ mixture triggered the formation of vaterite; these findings were corroborated by FTIR and Raman techniques. The spherical nanostructures have an average diameter size of 4.3 ± 2 μm and an average roughness (R_a) of 3.11 ± 0.62 μm. Zeta potential (ζ) and isoelectric point studies reveal that this hybrid nanostructure exhibits amphoteric behavior that differs from either AgNPs or AgNPs–BSA alone. Cell viability response exceeded 75%, indicating the noncytotoxic nature of the proposed hybrid nanostructures.

Reduction of carboxamides is an efficient approach to obtain the corresponding amines, albeit it is one of the most problematic. In this work, by use of pinacolborane (HBpin) as a reductant, the rare-earth metal tris (arylamido) complex supported by a ferrocenyl-modified arylamido ligand La[NH-2,6-ⁱPr₂-4-FcC₆H₂]₃ was employed as a precatalyst for primary and secondary amide reductions. This catalyst system exhibited high activity toward hydroborative reduction of amides to amines under mild conditions, as well good tolerance for heteroatoms and functional groups in the reduction. A lanthanide hydride was experimentally verified as the active species and the reduction mechanism was proposed.

Nano-sized bivalent metal complexes, specifically [M(L)2] with L = 2-((E)-((4,5-dimethyl-2-(((E)-4-methylbenzylidene)amino)phenyl)-imino)methyl)benzenethiol] (C₂₃H₂₂N₂S) and M = Cu (II) (C1), Co (II) (C2), Ni (II) (C3), and Zn (II) (C4), underwent synthesis and subsequent characterization. Elemental analyses, infrared, NMR, mass, electronic, magnetic susceptibility, conductivity assessments, and X-ray diffraction studies were used to assess our bivalent metal complexes. DFT studies were used to study the tautomeric equilibrium of the tridentate thio-Schiff base ligand (HL), via the DFTB3LYP method in connection with a 6–311G* correlation consistent basis set. Two tautomers, which are thione and thiol forms, were studied to estimate the predominant one. The metal formed four coordinated with the tridentate N₂S donor thio-Schiff base to form octahedral geometry complexes. The SEM, TEM, XRD, AFM, and EDX of the studied complexes unveiled distinct and strong diffraction peaks, signifying their crystalline nature and providing evidence of their particle sizes being within the nano-size. The crystal sizes calculated for all complexes were determined to be ranging from 27.73 to 76.39 nm. The interactions between metal complexes and calf thymus DNA, and their potential for mimicking insulin activity, were investigated in a controlled lab setting by measuring their ability to inhibit alpha-amylase. The antimicrobial potential of thio-Schiff base ligand (HL) plus complexes (C1–C4) were tested. The viscosity and UV–Vis absorption determinations were utilized to assess the calf thymus DNA (CT-DNA) interaction with the nano-sized metal (II) chelates. Our flow cytometry data indicate significant levels of apoptosis and cell cycle arresting in both liver and breast cancer cell lines.

Organophosphorus pesticides are commonly employed in agricultural fields due to their potent insecticidal properties and short environmental persistence. However, organophosphorus pesticides enter the human body through the food chain, surface, and groundwater, leading to irreversible damage to the nervous system. Therefore, monitoring the presence of organophosphorus pesticides in food is necessary to ensure human safety. Herein, an ultra-sensitive electrochemical biosensor has been prepared by using graphitic carbon nitride decorated molybdenum sulfide (g-C₃N₄@MoS₂) as a catalyst for the detection of organophosphorus pesticides, trichlorfon. The synergistic effect of g-C₃N₄@MoS₂ boosts the electron transfer across the electrode surface, further contributing to the immobilization of acetylcholinesterase (AChE) enzyme using glutaraldehyde as a crosslinking agent. At optimum conditions, the developed biosensor (AChE/g-C₃N₄@MoS₂/ITO) demonstrated a broad linear range (5–100 nM) with a low detection limit (LOD) of 2.1 nM obtained using the equation 3σ/S where σ is the standard deviation and S is the sensitivity of the bioelectrode. In addition, the AChE/g-C₃N₄@MoS₂/ITO biosensor exhibited good stability and reproducibility, with satisfactory results for real sample analysis of trichlorfon detection.