Applied Organometallic Chemistry最新文献

The [Cd(DPPT)Cl₂] (1) and [Cd(DMPT)(NO₃)₂(H₂O)].H₂O (2) complexes of the 1,3,5-triazine ligands DPPT and DMPT were reported. 1 has slightly distorted square pyramidal geometry around the Cd(II) ion, while 2 adopted distorted triangular dodecahedral coordination geometry. Hirshfeld energy framework analysis showed that electrostatic and dispersion energies have a significant influence in stabilizing their crystal lattice. DFT calculations predicted that 1 and 2 have 36 and 35 times greater hyperpolarizability than urea suggesting the new Cd(II) complexes as promising candidates for nonlinear optical applications. Both complexes exhibit broad-spectrum activity against tested bacteria with inhibition zone diameters (IZDs) within the range of 17–35 mm and fungi (IZD = 15–20 mm), except for 1 against A. fumigatus. Both complexes outperformed the positive control gentamicin toward S. aureus. While gentamicin produced a 24 mm inhibition zone, complexes 1 and 2 achieved zones of 35 and 31 mm, respectively. Additionally, the Cd(II) complexes effectively inhibited the growth of HCT-116 and A-549 tumor cells. 1 is more active (IC₅₀ = 11.44 ± 0.23 and 7.86 ± 0.14 μM) than 2 (IC₅₀ = 16.30 ± 0.49 and 32.50 ± 1.12 μM) against these cells, respectively. Furthermore, the selectivity indices of Cd(II) complexes exceeded 1, suggesting their potential as antineoplastic factors.

This study addresses the challenge of developing sustainable and environmentally friendly methods for pinacol coupling, which has traditionally relied on harsh reaction conditions involving strong acids, reductants, and elevated temperatures or pressures. In the present study, visible-light-active photocatalysts were synthesized by doping CuFe₂O₄ at varying loadings, that is, 3%, 5%, and 10% onto a g-C₃N₄ matrix, resulting in 3%, 5%, and 10% CuFe₂O₄@g-C₃N₄ photocatalysts, respectively. These photocatalysts were evaluated for their photocatalytic efficiency in the pinacol coupling reaction under visible-light irradiation, specifically using a 12W white LED as the light source, and consistently outperformed pristine g-C₃N₄. Comprehensive catalyst characterization was performed through FTIR, XPS, XRD, HR-TEM, Mott–Schottky analysis, EIS, and UV–Vis DRS. Among these prepared catalysts, the 5% CuFe₂O₄@g-C₃N₄ catalyst achieved an outstanding 99.5% conversion rate and 98.3% selectivity, demonstrating robust stability with negligible activity loss after five consecutive recycling cycles. These findings highlight the potential of engineered CuFe₂O₄@g-C₃N₄ photocatalysts and mild visible-light-driven conditions as a green avenue for efficient pinacol coupling reactions.

The direct coupling of aldehydes and amines, known as oxidative amidation, toward synthesis of amides, is reported for the first time in Urea:CuCl₂.2H₂O deep eutectic solvent, which simultaneously also plays the role of a catalyst. tert-Butyl hydroperoxide (TBHP) was employed as a green oxidant, and all the reactions were performed at 80°C. More than 20 amide derivatives were synthesized in good to excellent yields.

Urea.2H₂O was employed as both a solvent and a catalyst for the synthesis of 22 amides with yields of up to 95% via oxidative amidation reactions of aldehydes and amine hydrochloride salts.

Ammonia (NH₃) detection is critical for environmental protection and industrial safety; however, conventional sensors face challenges, such as high-energy consumption and poor selectivity. In this study, a bifunctional breakthrough was achieved by repurposing a spent hydrodesulfurization (HDS) catalyst into a high-performance room temperature NH₃ sensor. Taking advantage of the inherent composition of the precursors, a green synthesis route was developed to convert the spent Ni-W/Al₂O₃ catalysts into layered nickel tungstate (NiWO₄) nanosheets by melt leaching. The derived NiWO₄ sensor exhibits excellent NH₃ sensing performance at room temperature with a response value of 14.76 for 100 ppm of NH₃, which greatly exceeds that of most reported metal semiconducting oxide (MOS) sensors. The improved sensitivity results from the synergistic effect of the material's lamellar morphology, abundant O_V, and optimized charge transport pathways. In addition, the sensor exhibits remarkable selectivity and long-term stability for NH₃. This work not only establishes a sustainable pathway for the conversion of hazardous industrial wastes into functional nanomaterials but also promotes the development of energy-efficient gas-sensing platforms, in line with the principles of a circular economy and the goals of green chemistry.

Three isostructural polyoxometalate–based hybrid materials, namely, [Zn₂(Hppb)₃(ppb)(H₂O)₂][PW₁₂O₄₀]·4H₂O (1), [Co₂(Hppb)₃(ppb)(H₂O)₂][PW₁₂O₄₀]·4H₂O (2), and [Co₂(Hppb)₃(ppb)(H₂O)₂][PMo₁₂O₄₀]·4H₂O (3) (where Hppb = 2-(3-(Pyridin-2-yl)-1H-pyrazol-1-yl)benzoate), were successfully synthesized under hydrothermal conditions. These compounds were fully characterized by single-crystal X-ray diffraction, FT-IR, PXRD, UV–Vis DRS, and TGA. In each structure, Keggin-type polyoxometalate clusters are anchored within the metal–organic framework through hydrogen-bonding interactions. The photocatalytic activities of these hybrids were evaluated through the degradation of organic dyes under xenon lamp irradiation. Compound 1 demonstrated exceptional performance, achieving 94.2% removal of MB and 87.9% removal of RhB. The degradation processes followed pseudo-first-order kinetics, and radical trapping experiments revealed that h⁺ and ·OH serve as the main active species for MB and RhB degradation, respectively. The enhanced photocatalytic efficiency of 1 is attributed to the synergistic effect between the metal–organic matrix and the polyoxometalate units, which significantly improve light harvesting and charge transfer dynamics. This work provides valuable guidance for the development of high-efficiency POM-based hybrid materials for environmental photocatalytic applications.

A viable strategy for harnessing hydrogen energy that can be sustainably supplied, conveniently stored, and transported lies in the advancement of electrocatalytic materials tailored for water electrolysis. These catalysts must exhibit exceptional activity, long-term operational stability, and economic viability. Metal–organic frameworks (MOFs) have recently emerged as a class of electrocatalytic materials with tailored superiority. This is because they possess an ultrahigh specific surface area along with numerous potential active sites. In this paper, we designed and synthesized a special bimetallic and double-ligand MOF nanomaterial. Within a 1-M KOH solution, the synergistic interaction of two metal ions and the electron-transfer influence of dual ligands boost the electron-transfer efficiency of the oxygen-generating electrochemical process (formally designated as OER) and overall water electrolysis. For the prepared Ni₆Fe₄-BD@NF nanomaterial, at 15 mA cm⁻², the electrode achieves a remarkably low OER overpotential of 270 mV, accompanied by an ultralow Tafel slope of 22.77 mV dec⁻¹. At 100 mA cm⁻², the OER overpotential measured exhibits a value of 390 mV. The electrocatalytic performance of the Ni₆Fe₄-BD@NF nanocomposite significantly outperforms its single-metal counterparts with distinct ligand coordination environments. Specifically, at 15 mA cm⁻², the overpotential required for OER is 320 mV for Ni-BD@NF (double-ligand system), 340 mV for Ni-B@NF, and 360 mV for Ni-D@NF (single-ligand system). When integrated into a full water electrolysis cell, the system operates at a voltage of 1.509 V for 100 h to attain a current density of 20 mA cm⁻². Experimental findings demonstrate that the incorporation of metal ions, the design of double-ligand MOFs, and nanoization of MOF materials are straightforward and effective approaches to enhance the electrocatalytic properties of MOFs.

A new TPP/Ag₃PO₄ photocatalyst composite was synthesized for the first time via simple doping. A series of the new type of composite materials with different mass ratios were prepared by doping silver phosphate obtained by precipitation onto 5,10,15,20-tetraphenylporphyrin (TPP) through a simple physical agitation method. Photocatalytic performance optimization led to the identification of a 1:10 composite mass ratio as optimal. It was found that the catalytic degradation efficiency of RhB was close to 100%, and the efficiency could still reach 92.04% after repeated catalysis. SEM imaging reveals that Ag₃PO₄ particles are evenly distributed across the expansive planar morphology of TPP. The successful combination of the two materials and excellent photoelectric performance of the composite material were further validated through XRD, SEM-EDS, XPS, EIS, and other analyses. Experimental studies on the degradation mechanism showed that •O₂⁻ played a leading role in its photocatalytic degradation of RhB. It is found that the organic heterojunction structure formed by TPP and Ag₃PO₄, and depending on the low potential of the LUMO orbital of TPP, can effectively inhibit the recombination of photogenerated carriers in the catalyst, ensuring the smooth transfer of photogenerated carriers in the material. Therefore, the material demonstrates both exceptional photocatalytic performance and excellent reusability.

The global shift toward renewable energy solutions necessitates the development of efficient electrocatalysts to overcome the limitations of current oxygen evolution reaction (OER) systems in water electrolysis. Herein, we report a hydrothermally synthesized polyoxovanadate-based metal–organic framework, [Co (bix)_1.5(mim)][V₂O₆] (Co-V-MOF, bix = 1,4-bis (imidazol-1-ylmethyl)benzene, mim = 1-methylimidazole), featuring a distinctive 3D architecture with bimetal {V₄Co₂} inorganic layers bridged by bix ligands. Electrochemical characterization demonstrates OER activity with a low overpotential of 350 mV (at 10 mA·cm⁻² in 1 M KOH), surpassing commercial RuO₂ benchmarks. The material's operational durability is evidenced by minimal potential degradation during extended testing, while its favorable charge-transfer kinetics are reflected in a reduced Tafel slope and impedance. Complementary magnetic investigations indicate the emergence of antiferromagnetic associations at the Co²⁺ nodes. This study establishes polyoxovanadate-MOF hybrids as a new class of high-performance electrocatalysts for sustainable energy conversion systems.

The transformation of carbon dioxide (CO₂) into high-value-added chemical products constitutes a prospective avenue for constructing a carbon-neutral society and promoting energy storage. For this purpose, the design and synthesis of efficient catalysts for the generation of cyclic carbonates from CO₂ and epoxides is of crucial significance. In the present research, a three-dimensional porous, flower-shaped Ni/Zn-MOFs has been synthesized via a hydrothermal approach. This framework acts as a precursor for the synthesis of the NZC-550 catalyst. The obtained NZC-550 catalyst serves as a retrievable heterogeneous catalyst in the cycloaddition reaction of CO₂ and epoxides, attaining satisfactory outcomes. A series of characterization methods such as XRD, FESEM, TEM, HAADF-STEM-EDS, XPS, and Raman reveal that the NZC-550 catalyst demonstrates remarkable performance in the CO₂ cycloaddition reaction. This could be ascribed to its hierarchical architecture and the cooperative effects between Ni₃ZnC_0.7 alloy and ZnO. Additionally, the NZC-550 catalyst exhibits outstanding stability and activity throughout multiple reaction cycles. It is contended that this bimetallic MOFs-templated methodology furnishes valuable perspectives for the design of catalysts dedicated to CO₂ conversion reactions.

Although silver diamine fluoride (SDF) effectively prevents dental caries, it can cause undesirable tooth discoloration and may be cytotoxic. To address these limitations, we developed a fluoride-based composite that incorporates AgNP-doped metal–organic frameworks (MOFs) with a 5% sodium fluoride (NaF) solution (Ag@MOF-5/F). The AgNPs were anchored onto the nanosheets of synthesized MOF-5 and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Different concentrations of Ag@MOF-5/F (1 to 25,000 ppm) were prepared and assessed for antibacterial activity against Streptococcus mutans (S. mutans) and cytocompatibility with human gingival fibroblasts (HGF-1). The most effective concentrations (400 and 1400 ppm) were evaluated for potential staining of the prepared dentin specimen and compared against 5% NaF and 38% SDF. Ag@MOF-5/F demonstrated potent antibacterial activity with a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) against S. mutans at 25 ppm. HGF-1 cell viability remained above 49% at 400 ppm and 37% at 1400 ppm, which indicated enhanced biocompatibility compared with the SDF (23%) and NaF (31%). There was no perceptible tooth discoloration with Ag@MOF-5/F, in contrast to the pronounced black staining caused by SDF. This study introduces a novel Ag@MOF-5/F formulation that combines broad-spectrum antibacterial efficacy with favorable cytocompatibility and superior aesthetic outcomes for caries management.