Applied Organometallic Chemistry最新文献

Based on the policy of building a beautiful China and the increasing demand for natural gas, the technology of converting coal to natural gas is receiving more and more attention. The Ni-based methanation catalyst is prone to being poisoned and deactivated because coal-based synthesis gas contains sulfides. Therefore, it is urgent to develop a sulfur-tolerant methanation catalyst. MoS₂/CeO₂–Al₂O₃ sulfur-tolerant methanation catalysts were prepared with a DBD plasma fluidized bed. The effect of plasma atmospheres (Ar, H₂, and air) and promoters (Ni and Co) on catalyst structure and performance was studied. It was found that catalysts pretreated in an air atmosphere exhibited the highest CO conversion, which is over 10% higher than that in Ar and H₂, and CH₄ selectivity is also 8.94% higher than traditional calcination. Co doping resulted in more S vacancies in the catalyst, increasing its activity to 36.42%. Ni is more attached to the carrier in the form of oxides, forming Ni₃S₂ after sulfurization, which covers some of the hydrogenation active sites and leads to a decrease in activity.

Two new types of osmium complexes, PNN-osmium complex (Os1) and NN-osmium complex (Os2) have been developed and proven to be effective catalysts for the transfer-dehydrogenative (TDH) oxidation of various (hetero)aromatic, cycloalkyl, and aliphatic alcohols to the respective ketones (55 examples). Notably, both complexes have been fully characterized and their comparative performance as catalysts investigated; Os1 has been further proven more effective in TDH oxidation of alcohols with a high turnover number (TON) reaching up to 63,000. Comparative experiments and DFT computations indicate that PNN-complex Os1 exhibits higher reactivity in transfer-dehydrogenative reactions than its NN counterpart Os2 due to the steric hindrance of catalysts. A joint theoretical and experimental investigation further shows that the current osmium system follows an outer-sphere bifunctional mechanism, which involves the transformation between osmium hydride and amido-osmium species. Furthermore, these osmium catalysts show great potential promise for applications in atom-economic synthesis of ketonic fine chemicals.

In this research, GO/Cu/Cr-MOF composites were fabricated via a dissolution-heat method. The GO/Cu/Cr-MOF composite was characterized using FT-IR, SEM, XRD, and EDS techniques. The characterization results confirmed the presence of Cu and Cr metallic elements in the composite, and FT-IR analysis demonstrated that the organic ligands were successfully coordinated with the metal centers. The characterized GO/Cu/Cr-MOF composite was employed in the removal study of fleroxacin and levofloxacin. The results demonstrate that the addition of 40 mg of the composite to a 40-ppm levofloxacin solution achieved a removal efficiency of 95.9% within 5 h. Likewise, adding the same amount of composite to a 20-ppm fleroxacin solution resulted in a maximum removal efficiency of 98.2% over the same time period. The experimental data were examined using both the kinetic model and the isotherm models. The results revealed that the adsorption of both antibiotics onto the GO/Cu/Cr-MOF composite followed the pseudo-second-order kinetic model and was most accurately represented by the Langmuir isotherm. The experimental results indicate that the adsorption capacity of the GO/Cu/Cr-MOF composite for fleroxacin and levofloxacin reaches its maximum within the pH range of 6 and 8.

Nowadays, the textile industry is looking for sustainable and green processes that can provide peerless alternatives to conventional toxic chemicals. The purpose of the present work is to develop multifunctional linen using an ultrasonic-assisted in situ synthesis of ZnO nanoparticles on a chitosan-coated linen fabric utilizing coffee bean extract (CBE). The CBE, as a reducing agent, helps synthesize nanoparticles. To evaluate the reducing capability of natural extract at different pH, reduction–oxidation potential was measured. The samples prepared at pH 7, 9, and 12 were characterized using Fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscope, and energy-dispersive X-ray spectroscopy to define surface characteristics, nanoparticle size, and elemental mapping and to show necessary chemical bondings. Wrinkle resistance, antioxidant activity, UV protection, and antibacterial properties of the modified linen were evaluated. The durability of these functional properties was assessed against laundering treatments. The use of ultrasonic waves facilitated the formation and distribution of nanoparticles resulting in multifunctional linen with excellent functionalities durable up to 20 washes. The optimized sample showed antibacterial activity higher than 85% against both E. coli and S. aureus, antioxidant activity above 66%, and a UV protection factor greater than 22.

Sorafenib (SOR) has fast-track review status due to its dual tumor-inhibitory mechanism, but its clinical use is limited by severe side effects. This study aimed to develop a new nanocarrier to encapsulate SOR, leveraging the rise of nanomaterials in drug delivery. A coordination molecular container (CoTPE) was synthesized through the self-assembly of 4′-(1,2,2-triphenylvinyl)-[1,1′-biphenyl]-3,5-dicarboxylic acid as a bridging ligand with Co(II) and sulfonyl-bridged calix[4]arene. The resultant structure, comprising a cylindrical internal cavity and four bowl-like external cavities, was characterized by single-crystal X-ray diffraction. Spectroscopic titration further validated the ability of the molecular container to encapsulate SOR, exhibiting pH-sensitive, controlled-release behavior. Subsequent in vitro and in vivo assessments revealed that CoTPE displayed favorable biocompatibility and enhanced tumor-suppressing efficacy relative to free SOR. This study not only introduces a promising strategy for the targeted delivery of SOR in liver cancer therapy but also expands the utility of innovative supramolecular materials and molecular containers in biomedical and pharmaceutical applications.

A series of N-pyridyl-N′-thioether-functionalized imidazolium salts (2a–d) were synthesized through quaternization of thioether-substituted imidazole precursors (1a–d). Subsequent metalation with PdCl₂ and following anion exchange reaction with CF₃COOAg yielded the corresponding NCS–pincer N-heterocyclic carbene Pd complexes (NHC–Pd, 3a–d and 4a–d). Comprehensive structural characterization was performed using NMR spectroscopy and high-resolution mass spectrometry (HR-MS), with the molecular structure of 3b unequivocally confirmed by single-crystal X-ray diffraction analysis. Catalytic evaluation revealed these complexes to be highly effective catalysts for Buchwald–Hartwig cross-coupling reactions between chloroarenes and various cyclic secondary amines. Under optimized conditions, the NHC–Pd catalysts exhibited high catalytic efficiency at low loading (0.5 mol%), demonstrating excellent functional group tolerance (including both electron-donating and electron-withdrawing groups at o-position, m-position, and p-position), broad compatibility with heteroaromatic substrates, and practical utility in pharmaceutical synthesis. These well-defined complexes, featuring straightforward synthesis and exceptional catalytic performance, represent promising candidates for C–N coupling applications.

S,S′-bis(2-pyridylmethyl)-1,2-thiobenzene (bptb) ligand, KSCN and its cobalt and nickel metal salts formed two new complexes, [Co^II (bptb)(SCN)₂] and [Ni^II (bptb)(SCN)₂], respectively. They were all efficient catalysts that can reduce protons or water to hydrogen by electrocatalysis or photocatalysis. The complexes [Co^II (bptb)(SCN)₂] and [Ni^II (bptb)(SCN)₂], adopting a square pyramidal coordination structure, exhibited efficient activity in electrocatalytic proton reduction with acetic acid (AcOH) as the proton source in N,N′-Dimethylformamide (DMF) solution, providing 108.4 and 292.3 (mol H₂/mol catalyst/h) for hydrogen evolution at an overpotential of 400 mV, respectively. In neutral buffer solution (pH 7.0), the complexes [Co^II (bptb)(SCN)₂] and [Ni^II (bptb)(SCN)₂] exhibit excellent hydrogen evolution activity, showing turnover frequencies of 993.7 and 1484.9 mol H₂ (mol catalyst)⁻¹ h⁻¹ with an applied overpotential of 837.6 mV, respectively. Under blue light irradiation, the photolysis of aqueous solutions (pH 4.5) containing complexes [Co^II (bptb)(SCN)₂] and [Ni^II (bptb)(SCN)₂] with CdS as the photosensitizer and ascorbic acid (H₂A) as the electron donor, exhibited remarkable photocatalytic hydrogen evolution activity, achieving turnover numbers (TON) of 16,710.2, and 17,926.1, respectively. The corresponding average apparent quantum yields (AQYs) were 17.8% and 18.7%. Notably, the examined metal cobalt and nickel complexes exhibited highly efficient hydrogen evolution reaction (HER) activity, and their catalytic activity following the nickel complex was superior to that of the cobalt complex in both electrochemical and photochemical conditions.

Transition metal complexes, particularly those derived from Schiff bases, are of considerable interest due to their multifunctional biological and photocatalytic properties, especially in formate production and hydrogen evolution. In this study, two nickel(II) complexes, [Ni(L¹)(pyS)] (1) and [Ni(L¹)(MBT)] (2), were synthesized and systematically evaluated for their photocatalytic and biological performances. Various organic dyes were employed as photosensitizers, while amines or bases served as sacrificial electron donors for visible-light-driven (> 420 nm) CO₂ reduction and hydrogen generation. The photocatalytic conditions were optimized by varying the pH (7–12.5), solvent ratios, and catalyst concentrations (2 mM). Density functional theory (DFT) studies revealed that complex 2 has a lower activation energy barrier (0.025 eV) for CO₂-to-formate conversion than complex 1 (0.043 eV). Both Ni(II) complexes demonstrated strong interactions in DNA/BSA binding studies, notable cytotoxicity toward HCT 116 (human colorectal carcinoma) cells, minimal toxicity toward NIH-3T3 (mouse embryonic fibroblast) cells, effective DPPH radical scavenging activity, and pronounced antimicrobial effects. Complexes 1 and 2 exhibited IC₅₀ values of 16.55 ± 0.05 μM and 13.99 ± 0.05 μM, respectively, comparable to cisplatin (IC₅₀ = 7.05 ± 0.05 μM). These findings highlight the dual potential of the synthesized Ni(II) complexes as efficient photocatalysts and promising candidates for biomedical applications.

The family of Fe (II) complexes (1–8) bearing 4′-(substituted-phenyl)-2,2′:6′,2′′-terpyridine ligands were prepared and characterized, in which the para-position of the phenyl is substituted by hydrogen (L¹), methyl (L²), F (L³), Cl (L⁴), I (L⁵), methoxy (L⁶), carboxyl (L⁷), and methylsulfonyl (L⁸). Compounds 2, 4, and 6 are dinuclear structures bridged by one water molecule, while the other five compounds are mononuclear. Compounds in vitro antiproliferative activity and cytotoxicity were evaluated against three human carcinoma cell lines: Eca-109 (esophageal squamous carcinoma), Bel-7402 (hepatocellular carcinoma), SiHa (cervical squamous carcinoma) and the normal HL-7702 hepatocyte line. The results demonstrate that the complexes exhibit superior antiproliferative activity against cancer cells compared to cisplatin, while showing significantly lower cytotoxicity toward normal cells. Among them, 3 (F-substituted) displayed the lowest IC₅₀ values against Eca-109 and Bel-7402, whereas 2 (methyl-substituted) showed the highest potency against SiHa. UV-vis and circular dichroism (CD) spectroscopic studies revealed intercalative binding between the complexes and DNA, a mechanism further corroborated by molecular modeling. These findings highlight the potential of complexes 1–8 as promising candidates for chemotherapeutic agents targeting human tumors, warranting further preclinical investigation.