Transition Metal Chemistry最新文献

This study identifies the novel palliated magnetic nanoparticles, Pd@CuFe₂O₄/BPMAEA, as an efficient and sustainable catalyst for Suzuki and Sonogashira cross-coupling reactions. The catalyst is synthesized by integrating palladium onto a magnetic CuFe₂O₄ support, which is functionalized with N,N-bis(2-pyridylmethyl)amine ethylamine (BPMAEA) as a ligand. This strategic design enhances palladium’s catalytic activity and stability while enabling easy separation and recovery of the catalyst from reaction mixtures. Comprehensive characterization techniques, including FT-IR, TEM, XRD, SEM, EDX, and VSM, confirm the successful synthesis of the Pd@CuFe₂O₄/BPMAEA nanoparticles, showcasing favorable structural and magnetic properties. The catalytic performance of the catalyst was assessed under various reaction conditions, demonstrating its remarkable efficiency in promoting both Suzuki and Sonogashira reactions with high yields and selectivity. Notably, the Pd@CuFe₂O₄/BPMAEA catalyst exhibits excellent reusability with minimal activity loss over multiple cycles, highlighting its potential for practical applications in organic synthesis. This research underscores the significance of developing sustainable catalytic systems that enhance reaction efficiency and minimize environmental impact using recoverable materials. Our findings contribute to advancing green chemistry practices in catalysis, paving the way for future innovations in sustainable organic transformations. The catalyst could easily and successfully be recycled up to six times with an E-factor as low as 29.48, a testament to its impressive efficiency and the potential it holds for the future of sustainable catalysis.

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Efficient ammonia synthesis is a significant but challenging target. One of questions faced by Ru-based ammonia synthesis catalyst is the hydrogen poisoning of Ru. In this work, we developed a strategy to greatly alleviate the effect by regulating hydrogen acceptance capacity of support MgO, thereby promoting the ammonia synthesis rate. To this end, three kinds of MgO (i.e., MgO nanocube (MgO-c), MgO nanoplate (MgO-p) and MgO nanosphere (MgO-s)) were chosen as the support of Ru catalysts for ammonia synthesis. The ammonia synthesis rate of 4Cs–Ru/MgO-c is 4466 μmol g⁻¹_cat h⁻¹, higher than the 2Cs–Ru/MgO-p (3483 μmol g⁻¹_cat h⁻¹) and Cs–Ru/MgO-s (2080 μmol g⁻¹_cat h⁻¹) at 350 ℃ and 0.1 MPa. The kinetic analysis results show that the value of the hydrogen reaction order is 4Cs–Ru/MgO-c > 2Cs–Ru/MgO-p > Cs–Ru/MgO-s > 0, indicating that no hydrogen poisoning occurs. The H₂-TPR and in situ FTIR characterizations show that MgO-c support has more active sites which can accept hydrogen atoms from the Ru surface as compared to the other two kinds of MgO. Meanwhile, the active sites released from the Ru surface can be used for N₂ activation, which will reduce the reaction activation energy of ammonia synthesis. Therefore, MgO containing abundant active sites for accepting hydrogen atoms can be expected to be a promising commercial catalyst support for Ru-based ammonia synthesis.

A new Ni^II two-dimensional coordination polymer [Ni₂(CN₂N)₂L]_n (1) is rendered assimilating the metal salt, Ni(ClO₄)₂·6H₂O, H₂L [N,N′-bis(3-methoxysalicylidenimino)-1,3-diaminopropane] and the co-ligand, sodium dicyanamide [NaN(CN)₂]. In the asymmetric unit, one Ni^II ion belongs on a distorted octahedral framework, whereas, the distorted tetrahedral geometry is procured by the other Ni^II ion. The two CN₂N²⁻ anions bridge between nickel centers in adjacent molecules resulting in the formation of a two-dimensional coordination polymer with a (6³) topology. The magneto-structural concurrence with variation of temperature (T) divulges that a weak anti-ferromagnetic interaction endures between two adjacent Ni^II centers where the χ_MT value is 1.20 cm³ mol⁻¹ K. The electrochemical study is implemented that manifests the redox peaks concerning the reduction and oxidation potentials of Ni(II) system. Furthermore, complex 1 impedes the cell growth of human colorectal carcinoma cells (COLO 205 cells), human lung carcinoma cells (A549 cells), and human hepatocellular carcinoma cells (PLC5 cells). In human colorectal carcinoma cells (COLO 205 cells), the highest inhibitory activity with 46.00 ± 1.09 μM IC₅₀ is revealed.

The CoFe₂O₄/g-C₃N₄ (CF/GCN) heterojunction was successfully synthesized by a sol–gel auto-combustion method. In synthesis, cow urine was used as a stabilizing and chelating agent. Further, the synthesized CoFe₂O₄ (CF), g-C₃N₄ (GCN), and CF/GCN heterojunctions were characterized utilizing X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV–visible diffuse reflectance spectroscopy (DRS) techniques. The findings show that the heterojunction is composed of spherical cobalt ferrite nanoparticles attached to the graphitic carbon nitride nanosheets. The synthesized photocatalysts' optical characteristics were examined, and the findings demonstrated that the heterojunction between CF and GCN enhanced light absorption, decreased the band gap, and separated the e⁻/h⁺ pairs. Photocatalytic efficacy of the CF/GCN was assessed by degrading of methylene blue (MB) and methyl orange (MO) under visible light irradiation. The photocatalytic efficacy of the CF15/GCN photocatalyst was higher than pure CF and GCN nanoparticles. Under stimulated visible light, it decomposed MB up to 93.61% and MO up to 88.42% in 90 min, which is greater than that of pure CF (49.71%; 44.12%) and GCN (37.14%; 31.21%). This substantial improvement can be attributed to synergistically enhanced electron/hole pair separation in CF15/GCN heterojunction. Also, the possible degradation mechanism has been proposed according to experimental results.

Non-platinum (non-Pt) coordination compounds display great potential as antineoplastic drugs. Herein, two new 8-hydroxyquinoline-N-oxide (H-8QOL) non-Pt coordination compounds, [Co^II(8QOL)₂(biq)] (Yulin Normal University-2a, YNU-2a) and [Co^III(8QOL)₂(phe)]NO₃·CH₃OH (YNU-2b), bearing 2,2′-biquinoline (biq) and 1,10-phenanthroline (phe) as auxiliary ligands, respectively, were synthesized and evaluated for their potential anticancer efficacy. A third compound, [Co₂(biq)₂(NO₃)₂(OCH₃)₂] (YNU-2c), was used as the control. YNU-2a demonstrated superior antineoplastic activity compared to cisplatin (CCDP), YNU-2b, and YNU-2c against human cisplatin-resistant lung adenocarcinoma A549/DDP (A549C) cells. And YNU-2a–YNU-2c exhibited lower cytotoxicity towards normal embryonic kidney (HEK293) cells than that of CCDP. The different cytotoxicities of YNU-2a–YNU-2c against the A549C cells depended on auxiliary ligands, following the order phe < biq. Further analyses revealed that YNU-2a more obviously suppressed A549C cancer cell proliferation via triggering mitophagy, inhibiting the production of ATP and mitochondrial respiration complexes I (MR1) and IV (MR4), and inducing mitochondrial dysfunction compared with YNU-2c. This study demonstrates that YNU-2a facilitates targeted mitophagy, highlighting its potential as an anticancer drug.

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Two novel polynuclear copper-based complexes, [(CH₃)₂NH₂]₂[Cu(II)₂Cu(I)₂(L¹)₄Bpy]·2H₂O (Complex-1) and [Cu₂(L²)₂(im)₂(H₂O)₂] (Complex-2), were synthesized . (H₂L¹: 4-chloro-5-(4-methylphenyl)-1H-pyrazole-3-carboxylic acid; H₂L²: 4-chloro-1H-pyrazole-3-carboxylic acid; Bpy: 4,4′-bipyridine; im: imidazole). The structures of the complexes were characterized by infrared absorption, X-ray powder diffraction, and single-crystal X-ray diffraction, with their thermal stability and Electrochemiluminescence (ECL) properties investigated. In Complex-1, Cu(I) and Cu(II) adopt planar trigonal and planar tetragonal coordination geometries, respectively, while Cu(II) in Complex-2 exhibits a slightly distorted trigonal pyramidal coordination geometry. Both complexes demonstrated good thermal stability below 260 °C. Complex-1 exhibited superior Electrochemiluminescence (ECL) performance, maintaining a maximum ECL intensity of 1447.20 a.u. even after removal of potential singlet oxygen interference.

Six new [Cu(XQ)₂] complexes (HXQ are derivatives of 8-hydroxyquinoline bearing methyl or aldehyde functional groups) were prepared with an emphasis on their preparation in a crystalline state using liquid-liquid, vapour-liquid and horizontal diffusions. Their composition is [Cu(dClMeQ)₂] (1), [Cu(dBrMeQ)₂]_n (2), [Cu(dIMeQ)₂]_n (3), [Cu(AQ)₂]_n (4), [Cu(dBrAQ)₂]_n (5) and [Cu(dIAQ)₂]_n (6) (HdClMeQ is 5,7-dichloro-8-hydroxyquinaldine, HdBrMeQ is 5,7-dibromo-8-hydroxyquinaldine, HdIMeQ is 5,7-diiodo-8-hydroxyquinaldine, HAQ is 8-hydroxyquinoline-2-carbaldehyde, HdBrAQ is 5,7-dibromo-8-hydroxyquinoline-2-carbaldehyde and HdIAQ is 5,7-diiodo-8-hydroxyquinoline-2-carbaldehyde). The complexes were characterised by infrared and UV-vis spectroscopy, elemental analysis and X-ray structural analysis (except 1). Deprotonated XQ ligands bind as bidentate chelates to the copper atom via the oxygen and nitrogen atoms of 8-hydroxyquinoline rings in all five compounds in the equatorial plane of an elongated tetragonal bipyramid. Oxygen (2c, 4c-6c) or iodine atoms (3c) of neighbouring [Cu(XQ)₂] molecules occupy axial positions and polymeric structures are thus formed, which are stabilised by hydrogen bonds and π-π interactions. This is a probable reason for their insolubility in a wide range of solvents. Crystal packing was further investigated by Hirshfeld surface analysis.

This study reports the synthesis and thorough characterization of two semi-organic crystals, (C₅H₇N₂)₂[ZnX₄] (X = Cl, Br), grown by the slow evaporation solution technique. Single-crystal X-ray diffraction revealed that compound (1) crystallizes in the tetragonal system (I4̅2d) and compound (2) in the orthorhombic system (P2₁2₁2₁), both non-centrosymmetric. Hirshfeld surface analysis and fingerprint plots highlighted strong N–H…X hydrogen bonds between the organic cations and [ZnX₄] anions, enhancing structural stability. Phase purity was confirmed by powder X-ray diffraction, while Fourier-transform infrared spectroscopy validated the presence of key functional groups. UV–Vis absorption spectra showed prominent bands at 253 nm and 262 nm, attributed to π–π* transitions, with optical bandgap energies estimated using Tauc plots. Second harmonic generation measurements under P₂ω excitation exhibited intense green emission at 532 nm, confirming the materials nonlinear optical activity. Continuous symmetry measure analysis indicated near-ideal tetrahedral geometry of the [ZnX₄] anions. Thermal stability was assessed by thermogravimetric analysis, and scanning electron microscopy revealed irregular, micron-scale particles with irregular surfaces. Energy-dispersive X-ray spectroscopy verified the elemental composition, confirming zinc and halide incorporation. Overall, these results provide valuable insights into the structural, optical, and thermal properties, underscoring the potential of these materials for nonlinear optical applications and antibacterial activity.‏‏

Mn²⁺-, Ni²⁺-, and Co³⁺-doped pyrrhotite nanoparticles were synthesized via the hot injection thermolysis method. The optical and structural properties of the pure and doped pyrrhotite nanoparticles were studied using UV–visible spectroscopy. Powder X-ray diffractometry (p-XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to characterize the particles. p-XRD studies showed that doping had no effect on the basic structure of the nanoparticles. The doped nanoparticles showed the formation of single-phase monoclinic type pyrrhotite (Fe_1-xS) structure. UV–visible spectroscopy revealed that the incorporation of Ni²⁺, Fe³⁺, and Co³⁺ ions as dopants decreases the energy bandgap of the pyrrhotite nanoparticles. TEM images showed an increase in nanoparticle sizes with the incorporation of dopants. Both elemental mapping and EDX analysis of the doped nanoparticles reveal the presence of Mn²⁺, Ni²⁺, and Co³⁺ doping ions in the pyrrhotite lattice.

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Using a one-step co-reduction method, AgCu bimetallic nanoparticles have been successfully loaded onto few-layer boron nitride nanosheets (BNNSs), which possess high thermal conductivity. The structure and morphology of both the support and the catalyst were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). Furthermore, the influence of near-infrared laser irradiation on the catalytic performance of the catalyst was investigated. The study found that the Ag₁Cu₁/BNNSs nanocomposite exhibited significant catalytic activity in the reduction of 4-nitrophenol (4-NP). This nanocomposite had an activation energy of only 42.9 kJ/mol and maintained high catalytic activity even after six cycles. Additionally, it was found that near-infrared laser irradiation further enhanced the catalytic activity of the composite material. This enhancement was primarily attributed to the photothermal effect of Ag nanoparticles. Moreover, the BNNSs possess high thermal conductivity. They transferred the photothermal energy generated by the Ag nanoparticles to the external environment, thereby further enhancing the local thermal effect of the catalyst. This work provided a foundation for advancing near-infrared or solar photothermal-enhanced bimetallic nanocomposite catalytic systems.