Journal of Organometallic Chemistry最新文献

Using optically active (R)-3-cyclohexenecarboxylic acid as a template in the reaction with (AlMe₃)₂, the stable adduct Me₂Al(µ-O-CMe₂C₆H₉)(µ-Me)AlMe₂ and methylaluminoxane (MAO) were synthesized. It is demonstrated that the activity of obtained MAO in the reaction of 1-hexene di- and oligomerization, catalyzed with zirconocenes (Cp₂ZrCl₂, Ind₂ZrCl₂, raс-EB[THI]ZrCl₂), is comparable with commercial MMAO-12. The use of chiral templated MAO in a catalytic system provides a significant change in the stereoselectivity of the reaction. Therefore, the stereoselectivity of the oligomerization process can be influenced by the activator structure, underscoring the importance of taking into account the activator counterion during the alkene insertion into the catalytically active sites.

The monosubstituted cyclopentadienyl half-sandwich molybdenum(II) tricarbonyl complex [(η⁵-C₅H₄CO₂CH₃)Mo(CO)₃CH₃] (1) and its 1:1 inclusion compound with cucurbit[8]uril (1@CB8) have been prepared and characterised by elemental and thermogravimetric analyses, powder X-ray diffraction, diffuse reflectance UV–vis, solid-state ¹³C{¹H} MAS NMR, FT-IR, and Raman spectroscopies. The CO-releasing behaviours of 1, 1@CB8 and, for comparison, [(η⁵-C₅H₅)Mo(CO)₃CH₃] (2) and its 1:1 inclusion complex with CB8, were assessed using a deoxymyoglobin-carbonmonoxymyglobin assay. For assays performed in the dark at 37 °C, complex 1 undergoes thermally assisted spontaneous CO release, with ca. 0.5 equivalents of CO being released after 6 h. The half-life (t_1/2) of 325 min identifies 1 as a slow releaser when compared to complex 2 bearing the unsubstituted cyclopentadienyl ligand (t_1/2 = 25 min). CO release from 1 was promoted by exposure to UV light (t_1/2 = 85 min), establishing the complex as a photochemically activated CO-releasing molecule (photoCORM). For 1@CB8, t_1/2 for photo-assisted CO release increased to ca. 7 h, and for 2@CB8 the dark-release t_1/2 increased to 165 min, showing that molecular acceptors like cucurbiturils can be used effectively as second-sphere ligands to modulate the CO release profile of CORMs.

A Mn-based metal-organic framework Mn-CPP was synthesized and showed excellent chemodynamic therapy (CDT) effect. DOX was selected and loaded into Mn-CPP obtaining DOX@Mn-CPP to improve the therapeutic properties. DOX@Mn-CPP exhibited better drug release behaviors in the tumor environment than that in normal environment. Besides, the material displayed good biocompatibility to L929 cells and significant effect of lethality on 4T1 cells and Hela cells. The successful fabrication of DOX@Mn-CPP provided the potential application for the combination therapy of chemodynamic therapy and chemotherapy.

In platinum(II) di-ynes and poly-ynes the optical properties are influenced by the pattern of conjugation in the functionalised acetylide linker groups. We report the synthesis and characterisation of new Pt(II) di‑yne trans-[(Ph)(Et₃P)₂Pt–CC–Ar–CC–Pt(PEt₃)₂(Ph)] (Pt-M) and Pt(II) poly‑yne trans-[Pt(ⁿBu₃P)₂Pt–CC–Ar–CC–]_n (Pt-P) (Ar = 2,2′-bipyridine-4,4′-diyl) materials using analytical and spectroscopic techniques. The solid-state structure of the protected ligand precursor 4,4′-bis(trimethylsilylethynyl)-2,2′-bipyridine (LP₁) and the dinuclear Pt(II) di‑yne (Pt-M) have been determined by the single-crystal X-ray diffraction (SC-XRD) while the number average molecular weight (M_n), weight average molecular weight (M_w) and polydispersity index (PDI) of the Pt(II) poly‑yne (Pt-P) have been determined by the gel permeation chromatography/light-scattering (GPC/LS) methods (M_n/M_w/PDI = 55,210/88,560/1.6). The thermal stability of the protected and di-terminal alkynyl ligands, Pt(II) di‑yne (Pt-M) and Pt(II) poly‑yne (Pt-P) have been evaluated and are discussed. To delineate the impact of incorporating the heavy Pt(II) ion along the polymer backbone, optical absorption studies have been performed and are discussed in detail. The results of optical absorption studies, especially (Pt-M) have been compared to their 5,5′- and 6,6′-bis(ethynyl) substituted analogues to better understand the effect of ligand topology on the effective conjugation.

Noncovalent interactions in crystal packing play significant roles in the formation of extended network structures. Thus, this study aims to investigate the influence of noncovalent bonds, particularly halogen bonds, on the crystal packing of ferrocene derivatives. For this purpose, disubstituted ferrocene derivatives carrying both bromo and N-heteroaryl substituents, 1‑bromo-1ʹ-(Het)ferrocene [Het = 5-pyrimidyl (1), 2-pyridyl (2), and 4-pyridyl (3)] and 1‑bromo-2-(Het)ferrocene [Het = 5-pyrimidyl (4) and 4-pyridyl (6)], were synthesized. Here, we discuss a comparison of their molecular and crystal structures, with those of a related compound, 1‑bromo-2-(2-pyridyl)ferrocene (5). Although the crystal packings of 1–5 are classified into quasi-one-dimensional chain structures, their intermolecular interactions are different. Compounds 1–3 exhibit Br⋅⋅⋅cyclopentadienyl halogen bonds to form extended structures. In contrast, 4 shows the π–π stacking interactions between the pyrimidine rings of adjacent molecules, and 5 exhibits the Br⋅⋅⋅N halogen bonds between adjacent molecules. The crystal structures contained chiral molecules of opposing handedness.

Rational design of Z-Scheme photocatalyst with outstanding charge separation and robust redox capabilities for photocatalytic H₂O₂ generation and cyclohexane oxidation under mild conditions still poses a significant hurdle. In response to this challenge, ternary g-C₃N₄-Au-MoO_3-x composite catalyst was developed though combining in-situ reduced MoO_3-x-Au composite and exfoliated g-C₃N₄ nanosheets using an ultrasonic liquid-phase approach. In addition, variations in the synthesis procedures led to the preparation of g-C₃N₄₋MoO_3-x, g-C₃N₄-Au, and Au-g-C₃N₄₋MoO_3-x composites, aimed at exploring their effectiveness in both H₂O₂ production and catalyzing cyclohexane oxidation. Notably, the g-C₃N₄-Au-MoO_3-x composite exhibited an impressive optical rate of H₂O₂ generation at 723.18 µmol·L⁻¹·h⁻¹, achieving a 11.94-fold enhancement compared to Au-g-C₃N₄₋MoO_3-x. Meanwhile, the conversion rate of cyclohexane reached 11.59 %, with a high selectivity of 97.43 % towards KA oil (cyclohexanol and cyclohexanone), and a KA oil production rate of 1166.86 µmol·L⁻¹·g⁻¹. Through analyzing the photoelectrochemical properties and band energy structures, it has been established that the involvement of an Au mediator was essential and vital for the Z-Scheme electron transfer in g-C₃N₄-Au-MoO_3-x. The incorporation of a Z-scheme heterojunction has resulted in increased light absorption, reduced charge recombination rates, and a substantial elevation in the levels of ·O₂⁻ and ·OH radicals, leading to a significant enhancement in photocatalytic efficiency for both H₂O₂ generation and cyclohexane oxidation. This study opens the door to on-site immediate production of hydrogen peroxide to boost the oxidation efficiency in the photocatalytic cyclohexane oxidation process.

2-Phenyl ethanol with various substituents on the phenyl ring was oxidized by Fe(NO₃)₃·9H₂O in the present of trifluoroacetic acid (TFA) at 0°C to room temperature. The product was highly dependent on the electronic properties of the substituent. Weak electron-donating and electron-withdrawing groups (Such as CH₃, Cl, Br, and F) afforded good to excellent yields (95 – 64 %) of the corresponding phenylacetic acids. Moderate electron-withdrawing groups (Such as CF₃, COOH) resulted in ∼ 50 % yield of the corresponding phenylacetic acids. However, strong electron-withdrawing group (such as NO₂ and CN) hindered the reaction, the corresponding phenethyl trifluoroacetate was acquired almost quantitatively. Furthermore, the strong electron-donating group of methoxy highly promoted the oxidation, resulted in nitrated benzaldehydes and benzoic acids in relative low yields.

4-nitrophenol is a serious environmental pollutant due to its carcinogenic, mutagenic, and teratogenic properties, posing serious risks to aquatic life, plants, and humans even at very low concentrations. In the current work a simple, inexpensive, and ecologically appropriate approach for generating palladium nanoparticles (Pd-NPs) from palladium chloride and their potential for the reduction of 4-nitrophenol have been investigated. This method employs a non-toxic aqueous extract obtained from the aerial portion of Roylea cinerea, which functions as both a reducing and stabilizing agent. The Pd-NPs synthesis was confirmed through UV–vis spectroscopy, and were further characterized by techniques like FT-IR, SEM, EDX, and XRD analysis. The biosynthesized Pd-NPs had a spherical shape with diameters ranging from 20 to 30 nm. The presence of palladium in the Pd-NPs was confirmed by EDX analysis. The available functional groups on the surface of Pd-NPs were determined through FTIR analysis. Pd-NPs demonstrated catalytic efficacy in both Sonogashira and Suzuki coupling processes, as measured by UV–vis spectrophotometry during nitrophenol reduction. The findings demonstrate that the Pd-NPs exhibited significant catalytic efficiency, achieving the degradation of over 95 % of 4-nitrophenol within a 16-min timeframe. Following the catalytic reaction, the catalyst was effortlessly recovered through centrifugation, demonstrating its ability to undergo multiple catalytic cycles without a significant loss of activity (>90 % after five cycles).

Co-MoS₂@BC catalysts were prepared using pine cones as biochar source, and the surface morphology and microstructure of the catalysts were analyzed and the successful preparation of the materials was verified by adopting the characterization means such as BET, SEM, XRD, FTIR, TEM, XPS, Raman. At the concentration of tetracycline (TC) in water of 20 mg/L, the reaction system with catalyst participation resulted in 98.88 % pollutant removal and efficient degradation, and the effects of TC concentration, coexisting chemicals, initial pH, catalyst dosage, PMS dosage, and other factors on the catalytic performance of Co-MoS₂@BC were investigated. The results of quenching experiments and electron paramagnetic resonance (EPR) examinations were combined, the reactive substances whose main roles in the reaction process were identified as single linear oxygen (¹O₂), and the simultaneous presence of electron transfer-mediated non-radical pathways in the Co-MoS₂@BC/PMS/TC system was confirmed using Linear sweep voltammetry (LSV). The reaction process's intermediates were examined using liquid chromatography-mass spectrometry (LC-MS), which also offered potential degradation routes.