Applied Organometallic Chemistry最新文献

Ethylene oligomerization, a reaction of significant industrial relevance, was effectively catalyzed by Ni(II) immobilized within two distinct zirconium-based MOFs, namely, UiO-67 and UiO-67bpydc (bpydc = (2,2′-bipyridine)-5,5′-dicarboxylic acid). These frameworks differ in the nature of their anchoring sites, which in turn influences their catalytic performance. Under identical reaction conditions—1730 eq. of Et₂AlCl as co-catalyst, 10 bar of ethylene, 24°C, 1 h, and toluene as solvent—Ni(II) coordinated to the zirconium clusters of UiO-67 exhibited superior catalytic activity compared to Ni(II) bound to the bpydc linkers of UiO-67bpydc (1578 vs. 196 mmol Ni⁻¹ h⁻¹, respectively). Variation in the amount of Et₂AlCl co-catalyst and the applied ethylene pressure revealed that reducing the co-catalyst concentration to 870 eq. enhanced its catalytic activity (1930 mmol Ni⁻¹ h⁻¹) relative to 1730 eq., whereas further reduction led to complete loss of activity. In addition, the optimal ethylene pressure for achieving maximum activity was identified as 10 bar, while reactions conducted at 5 and 20 bar afforded lower activities of 1077 and 1464 mmol Ni⁻¹ h⁻¹, respectively.

Herein, the methods of co-precipitation and hydrothermal treatment were proposed to regulate the promotional effect of COS + CS₂ sulfation on the NH₃-SCR activity of Ce_0.5Fe_0.5O_x catalyst. The results indicated that the co-precipitation method contributed to the formation of Ce-Fe solid solution in Ce_0.5Fe_0.5O_x-CP catalyst, but the further hydrothermal treatment depressed the incorporation of Fe³⁺ into cubic fluorite CeO₂, promoting the formation of Fe₂O₃ crystals while decreasing the defective sites of catalyst. Furthermore, the different interaction of active components not only influenced the NH₃-SCR activity of Ce_0.5Fe_0.5O_x-CP and Ce_0.5Fe_0.5O_x-HT catalysts but also regulated the sulfation of COS + CS₂ on the catalysts surface. The further hydrothermal treatment decreased the concentration of iron species but increased the concentration of cerium species on the Ce_0.5Fe_0.5O_x-CP catalyst surface. COS + CS₂ sulfation increased the surface Ce³⁺/(Ce³⁺+Ce⁴⁺) and Fe²⁺/(Fe³⁺+Fe²⁺) molar ratios of Ce_0.5Fe_0.5O_x-HT effectively but decreased the calculated corresponding values of Ce_0.5Fe_0.5O_x-CP. Furthermore, Ce_0.5Fe_0.5O_x-HT-S exhibited larger deposited surface sulfate, stronger medium–strong acid sites, and more active oxygen than Ce_0.5Fe_0.5O_x-CP-S due to the better surface conversion of COS + CS₂.

Arsenate remediation remains a critical environmental challenge, motivating the development of efficient and scalable adsorbents. Here, we report a comparative study of monometallic Fe-MIL-88B and its bimetallic analogue Fe/Ni-MIL-88B synthesized via microwave-assisted methods, yielding crystalline frameworks with octahedral morphologies (~200 nm) and uniform metal distribution. Comprehensive characterization (XRD, FTIR, SEM, BET) confirms the integrity and porosity of both MOFs after synthesis. Adsorption experiments reveal rapid arsenate uptake for both materials, with equilibrium reached within 30 min. Kinetics follow a pseudo-second-order model, indicating an adsorption process dominated by chemisorption with additional contributions from physisorption, and equilibrium isotherms fit the Langmuir model, consistent with monolayer adsorption on homogeneous sites. Thermodynamic analysis at 298 K shows spontaneous adsorption for both materials: Fe-MIL-88B with ΔG° ≈ −20.6 kJ/mol, ΔH° ≈ −10.0 kJ/mol, and ΔS° ≈ +35.6 J/mol·K, and Fe/Ni-MIL-88B with ΔG° ≈ −24.5 kJ/mol, ΔH° ≈ −11.9 kJ/mol, and ΔS° ≈ +42.5 J/mol·K, indicating more favorable thermodynamics and a stronger entropic drive in the bimetallic framework. The monometallic Fe-MIL-88B exhibits a maximum arsenate capacity of 167.5 mg/g, while the bimetallic Fe/Ni-MIL-88B shows a superior capacity of 207.2 mg/g, demonstrating a clear synergistic enhancement from Ni²⁺ incorporation. Spectroscopic analyses (FTIR and XPS) corroborate the formation of Fe–O–As coordination bonds, supporting a chemically bonded adsorption mechanism, in addition to electrostatic interactions induced by Ni²⁺ sites. The presence of Ni²⁺ also improves structural stability against hydrolysis and maintains porosity after multiple adsorption–desorption cycles, highlighting the practical viability of the Fe/Ni-MIL-88B system for arsenate removal from water. Overall, the study underscores the advantages of integrating secondary metals into MIL-88B MOFs to boost adsorption performance through synergistic interactions, enhanced site diversity, and robust thermodynamic and structural features.

Hydrodehalogenation is an important transformation in chemical synthesis and environmental protection. Current synthesis strategies are involved in the use of various additives and expensive hydrogen sources in both homogeneous and heterogenous catalysis system. Na-modified Silicalite-1 zeolite supported Pd catalyst (Pd/Na₃S-1) successfully mediated the dehalogenation reaction using water as a hydrogen source without any additives, outperforming its counterparts on Na-free Silicalite-1 (Pd/S-1) and Beta (Pd/Beta) zeolites in activity. This is because excess Na⁺ ions in S-1 zeolite led to the generation of numerous highly active, electron-deficient Pd^δ+ (0 < δ < 2) and Pd⁴⁺ sites in the Pd/Na-S-1 catalyst, due to the electron transfer from Pd species to nearby Na ion or framework O atom. While Pd/S-1 exhibited a predominance of low-active Pd²⁺ species, and Pd/Beta catalyst contained Pd⁰ species that was primarily responsible for the generation of dehalogenation-coupling product.

The utilization of natural products sodium alginate and L-arginine as raw materials is a facile and efficient route to fabricate supported catalysts for heterogeneous reactions. In this work, the dopant–evaporation–pyrolysis (DEP) strategy was employed to prepare Co incorporated into nitrogen-doped carbon aerogels (Co@CN-larg) from CoZn-MOF-polymer (Co/Zn-MOF@SA-larg), in which Co/Zn-MOF@SA-larg introduced L-arginine (larg) linker as N dopant. The Co/Zn-MOF@SA-larg in N₂ atmosphere enabled in situ evaporation of Zn nodes during pyrolysis process, which could facilitate the derived catalyst with high Co dispersity, large specific surface area, as well as abundant basic sites. All of these unique advantages endow Co@CN-larg with higher catalytic efficiency in comparison with traditional catalysts (Co@CN-mim and Co@CN-urea), along with well stability and recyclability. This DEP strategy may provide a new guideline to synthesize industrial organic catalysis for other catalytic reactions.

In this study, four distinct ionic liquid–modified bimetallic magnetic nanoparticles (IL-BMNPs) were synthesized by one-step simple chemical reduction method. The catalytic performance of these tailor-made bimetallic catalysts integrated the hydrophilic characteristics of the ionic liquid (1-butyl-3-methyl imidazolinium tetrafluoroborate) along with the magnetic properties of the bimetals, which consist of iron and cobalt or cobalt and nickel. The Fe/Co and Co/Ni bimetallic nanoparticles were synthesized in the stoichiometric ratios of 1:3 and 3:1. Various characterization techniques were employed to analyze the synthesized nanoparticles, including Fourier transform infrared spectroscopy, UV-visible (UV-vis) absorption spectroscopy, X-ray diffraction studies, vibrating sample magnetometer, scanning electron microscope, and Energy dispersive X-ray analysis. The synthesized IL-BMNPs were used as catalysts for the degradation of all the isomers of nitroanilines (o-nitroaniline, m-nitroaniline, p-nitroaniline) in the presence of sodium borohydride at room temperature. Of the four IL-BMNPs, Co/Ni (3:1) NPs exhibited a higher rate of o-nitroaniline degradation due to its stronger catalytic activity compared to the other modified bimetallic nanoparticles. The progress of the degradation process was effectively tracked through the utilization of UV-vis spectroscopy, and it was observed that the reaction reached 100% degradation of the nitroaniline within a relatively short period of 25 min. In addition, p- nitroaniline was also degraded by the synthesized nanoparticles. Notably, the bimetallic combinations, such as Co/Ni (1:3) Co/Ni (3:1) and Fe/Co (1:3), accomplished 99% degradation of p-nitroaniline within 9 min. Furthermore, the reduction of m-nitroaniline resulted in 99% degradation using Co/Ni (1:3) NPs within 21 min.

Metronidazole (MNZ), a refractory nitroimidazole antibiotic, poses significant environmental risks due to its persistence in aquatic systems. In this study, a hollow-structured ZIF-67-derived CoS (ZD-CoS) catalyst was synthesized to activate peroxymonosulfate (PMS) under simulated sunlight for MNZ degradation. The ZD-CoS/PMS system achieved 91.0% MNZ removal within 10 min under light irradiation, exhibiting a kinetic rate 2.4 times faster than that in the dark, which was attributed to the photothermal effect enhancing radical generation. The mechanistic study elucidated that the degradation of MNZ was driven by the collective contribution of reactive species, namely SO₄⁻˙, ˙OH, ¹O₂, and O₂⁻˙. This synergistic effect was primarily facilitated by the Co²⁺/Co³⁺ redox cycle, which served as the core mechanism for PMS activation. Furthermore, the degradation pathways of MNZ were elucidated through LC–MS analysis, indicating processes including hydroxylation, ring cleavage, and oxidation. The catalyst also demonstrated excellent stability over four cycles with low cobalt leaching (< 0.15 mg/L). This work provides a solar-driven, catalytic solution for antibiotic wastewater treatment and offers mechanistic insight into the degradation process.

An Ag(I)-catalyzed consecutive annulation/hydrophosphination of enynones with diaryl phosphine oxides has been developed, enabling the efficient one-step synthesis of diverse (1-hydroxynaphthalen-2-yl)methyl phosphine oxides in moderate to excellent yields. This transformation features mild reaction conditions, high efficiency, good substituent tolerance and excellent atom economy.

In this study, the properties of the electron transport layer (ETL) were improved by doping with zinc oxide (ZnO) nanoparticles (NPs) in a PFN solution. The organic solar cells (OSCs) were entirely fabricated and tested under regular atmospheric conditions by using active materials composed of fluorene (F) and diketopyrrolopyrrole (DPP) monomers called PFDPP-2 copolymer, combined with poly(3-hexylthiophene) (P3HT), and synthesized with 0.075% catalyst and PC₇₁BM in a fullerene ternary system. P3HT and PFDPP-2 polymers were synthesized by direct arylation polymerization. Additionally, a non-fullerene binary system based on (PBDB-T-2F [PM6]:BTP-4Cl [Y7]) was also analyzed. The solar devices based on this binary system, with ZnO NPs-doped in the ETL layer, adopted the structure glass/ITO/PEDOT:PSS/PM6:Y7/PFN:ZnO NPs/FM. Field's metal (FM) is a eutectic alloy used as a top electrode, deposited vacuum-free. In contrast, the ternary system was configured with glass/ITO/PEDOT:PSS/P3HT:PFDPP-2:PC₇₁BM/PFN:ZnO NPs/FM. In the ternary system, a 39.9% improvement in current density (J_sc) was observed upon doping with ZnO NPs, achieving a maximum power conversion efficiency (PCE) of 4.02%, 5.5% more with respect to the ternary reference and 24.8% considering only P3HT in the active layer. A similar behavior was observed in binary solar cells, resulting in a 51.8% increase in J_sc compared to the reference cell without ZnO NPs. For the non-fullerene OSCs, the maximum PCE of 11.84% was achieved, representing a 2.7% improvement compared to the reference binary system without ZnO NPs. Regarding stability, both systems (binary and ternary) maintained their transmission bands partially during the first 200 h of operation, indicating a significant improvement in the stability of both devices. However, in P3HT:PFDPP-2:PC₇₁BM cells, PCE decreased by 11% after 400 h, whereas in PM6:Y7 cells, stability improved by 5% under the same conditions.