Transition Metal Chemistry最新文献

A new MOF, {[Fe₁₅(µ₃-O)₅(L⁴⁻)₆(H₂O)₁₃(CH₃COO)₈]Cl₃}n (SYU-3, SYU for Shenyang University, H₄L = [1,1′:4′,1″-triphenyl]-3,3″,5,5″-tetracarboxylic acid), with (3,3,4,4,4,4,4,4,5,6,7)-connected nets, was synthesized via the combination of H₄L with FeCl₃·6H₂O in N,N-dimethylformamide/acetic acid solvent system. Interestingly, SYU-3 is isomorphic to Quin-Fe-TPTC, which is a five-component MOF based on the same metal and ligand and possesses cages and channels in it. However, SYU-3 shows a different valence state of iron and was obtained by a one-step reaction without the need to prepare Fe–O clusters in advance. Moreover, SYU-3 exhibits high water stability, it also shows 10.4 wt% carbon dioxide adsorption amounts under 298 K and 1 bar and 84.7 adsorption selectivity of carbon dioxide to nitrogen. Grand canonical Monte Carlo simulations show that both cages and channels provide carbon dioxide binding sites, which may result in the selective carbon dioxide adsorption of SYU-3.

Herein, we reported the synthesis and characterization of two new iridium(III) complexes [Ir(ppy)₂(fpp)](PF₆) (Ir1a, ppy = 2-phenylpyridine, fpp = 2-(2,2-difluorobenzo[1,3]dioxol-5-yl-1H-imidazo[4,5-f][1,10]phenanthroline) and [Ir(bzq)₂(fpp)](PF₆) (Ir1b, bzq = benzo[h]quinoline) through high resolution mass spectrometry (HRMS), ¹H NMR and ¹³C NMR. The cytotoxicity in vitro of Ir1a and Ir1b on normal NIH3T3 cells and cancer SGC-7901, A549, SK-Hep1 cells was tested using MTT (3-(4,5-dimethylthiazole-2-yl)-diphenyltetrazolium bromide) method. Ir1a exhibits high cytotoxicity on SGC-7901 cells (IC₅₀ = 2.7 ± 0.7 µM), whereas Ir1b shows moderate cytotoxicity toward the selected cancer cells. The ROS content was investigated using a fluorescence probe of 2′,7′-dichlorodihydrofluorescein diacetate (DCHF-DA), the results show that Ir1a and Ir1b elevate ROS content. The co-localization and the change of mitochondrial membrane potential were explored. Apoptotic studies using Annex V/PI double staining method demonstrate that Ir1a and Ir1b can efficiently cause apoptosis. Ir1a and Ir1b inhibit the cell proliferation at the G2/M period. Additionally, lipid peroxidation and downregulation of ferritin protein suggest that Ir1a and Ir1b can trigger ferroptosis.

An equimolar mixture of 2-amino-6-methoxybenzothiazole and 2-hydroxy-4-methoxybenzaldehyde was used to produce a Schiff base ligand 5-methoxy-2-(((6-methoxybenzothiazol-2-yl)imino)methyl)phenol, HL, which was then examined by elemental analysis, IR, ¹H NMR, ¹³C NMR and ESI-mass spectrometry. The Co(II), Ni(II) and Cu(II) chlorides, acetates and ligands were combined in ethanol in a molar ratio of 1:1 to create the metal complexes [1-C₁₆H₁₉CoClN₂O₆S, 2- C₁₈H₂₂CoN₂O₈S, 3- C₁₆H₁₅NiClN₂O₄S, 4- C₁₈H₁₈NiN₂O₆S, 5- C₁₆H₁₅CuClN₂O₄S and 6- C₁₈H₁₈CuN₂O₆S]. To identify the structure of all metal complexes 1–6, elemental analysis, molar conductance, electronic spectra and IR spectra were used. The ligand HL functions as an uninegative bidentate via phenolic O- and azomethine N- atoms, according to spectral data. Theoretical studies were performed to investigate the interaction between the metal ions and the ligand HL. This included analysis of the HOMO–LUMO gap to assess electronic properties, Hirshfeld charge distribution to understand electron density changes upon complexation and calculation of the binding energy to evaluate the stability of the metal–ligand complexes. The Co(II) complexes have been given an octahedral geometry, Ni(II) complexes a tetrahedral geometry and Cu(II) complexes a square planar geometry. Studies of the binding of the metal complex to bovine serum albumin (BSA) have been undertaken with the aid of fluorescence and circular dichroism spectrometry.

The article presents the results of flotation beneficiation experiments for polymetallic ore of complex mineralogical composition with the use of alkylbenzenesulfonic acid (ABSA) as a frothing reagent. Additional experiments showed the highest efficiency of ABSA application for samples of mixed-type ores, showing a significant increase in the recovery of gold, copper, zinc, and lead in the collective concentrates of flotation beneficiation. The use of an ABSA activator promotes the additional cleaning of fragments containing valuable metals from oxide films and coatings, as well as the transfer of microparticles of valuable metals due to the adsorption properties of organics and the formation of metal–carbon bonds. Another effect of this reagent use is an increase in the mass yield of concentrate while maintaining the quality parameters. Gold recovery in the main collective flotation concentrate more than doubled from 46.81 to 97.06%; copper recovery increased from 67.5 to 90.8%, zinc from 22.04 to 58.81%; and lead from 51.13 to 81.1% during the beneficiation process of polymetallic ore with the use of ABSA. A similar effect was observed for beneficiation of copper ore with complex composition; copper recovery in the main concentrate increased from 33.57 to 87.61%. Selective flotation with the development of gold concentrate from difficult-to-beneficiate polymetallic ore also showed a significant increase in gold recovery from 60.41 to 90.24% with ABSA pretreatment.

This study explores the synthesis, characterization, and optimization of zinc sulfide nanoparticles (ZnS-NPs) for the adsorption of Acid Green 25 (AG-25) dye from wastewater. ZnS-NPs were synthesized via the co-precipitation method and characterized by SEM, EDX, UV–Vis, FTIR, and XRD analyses, confirming a granular hierarchical structure, high purity showing a significant absorption peak at 310 nm and face-centered cubic crystal lattice with characteristic peaks matching with JCPDS file number 5-0566. The calculated band gap was 3.5 eV and the point of zero charge (PZC) was 5.84 indicating pH-dependent surface charge properties. Maximum adsorption was achieved using 0.3 g of ZnS-NPs adsorbent dose and 10 ppm of dye at pH 3 in 30 min; adsorption process followed the pseudo-first-order model (R² = 0.997) suggesting physisorption, while followed isotherm model was Temkin isotherm with R² = 0.8202 describing the adsorption equilibrium highlighting interactions between adsorbate molecules. Response Surface Methodology (RSM) optimization was used with Central Composite Design (CCD) to evaluate four factors such as pH, adsorbent dose, dye concentration and contact time to maximize adsorption efficiency. ANOVA analysis revealed a highly significant quadratic model (p < 0.0001) with optimal conditions for dye removal and validated experimentally with a negligible error of 1.2% compared to predicted values. The RSM model demonstrated high predictive accuracy with R² = 0.9784 and an insignificant lack of fit (p = 0.1337) underscoring ZnS-NPs as a robust, cost-effective and environmentally friendly adsorbent for industrial wastewater treatment.

A novel γ-Al₂O₃/IL-Pd catalyst was designed and synthesized; this catalyst features highly dispersed deposition of active palladium nanoparticles on the surface of porous γ-Al₂O₃, and its catalytic performance and recyclability are improved. The incorporation of ionic liquids is critical to catalyst design since it facilitates the complete dispersion of active metals through chelation; this effectively prevents the formation of palladium black and addresses catalyst deactivation. The interaction between the ionic liquid and the support likely occurs through specific coordination reactions; this interaction significantly enhances the recovery and reusability of the catalyst by preventing the leaching and sintering of the palladium nanoparticles. This approach not only resolves the agglomeration issue inherent to γ-Al₂O₃, but also further optimizes the catalyst performance. In the Suzuki‒Miyaura coupling reaction, the new catalyst demonstrates remarkable catalytic activity and achieves a tetramethoxybiphenyl yield of up to 99% within a remarkably short reaction time of just 30 min, without the need for inert gas protection. Notably, after ten consecutive cycles, the catalyst’s performance remains at 94%, outperforming many existing catalysts and confirming its exceptional stability and recyclability. Given its high efficiency, stability, and reusability, this catalyst can likely serve as a high-performance multifunctional catalytic platform for a range of significant organic synthesis reactions.

Graphical abstract

Electrochromism is the process of changing a material’s optical glaze from coloured to bleached and vice versa by applying a reversible voltage. It is worth noting that across all transition metal oxides, tungsten oxide (WO₃) has acquired a prime focus owing to its versatile electrochromic properties. High coloration efficiency, high diffusion coefficient (D), high cyclic stability, high optical modulation, and fast switching time are few properties which makes WO₃, a versatile electrochromic material. Over the years, many scientists and researchers have been encouraged to extravagant their work on WO₃, to realise its hidden electrochromic persona. Various nanostructured forms of WO₃ have been studied till now. Every form of WO₃ film defines a different electrochromic capability. In this review we try to portray versatility of various nanostructured forms of WO₃ such as nanowires, nanorods, nanotrees, nanoflowers, nanoflakes, and nanoporous films towards acquiring electrochromic state of the art.

Proton-coupled electron transfer (PCET) is a common reaction in biological systems, with potential implications for DNA damage and repair. This study showed that tris-(2-pyridine carboxylate) chromium (III) (complex 1) exhibited an increased electrochemical reaction rate in the presence of a strong acid, suggesting that PCET via proton donation promotes the reduction reaction. Conversely, complex 1 with picolinic acid showed a decreased electrochemical exchange constant, suggesting kinetic control by slow electronic exchange, consistent with PCET. Bis(pyridine-2,6-dicarboxylate) chromate (III) of sodium (complex 2), showed potential shifts and broadening of signals in the presence of dipicolinic and ascorbic acids, further supporting the involvement of PCET. Overall, the study highlighted the modulation of the electrochemical behavior of the chromium complexes through proton-coupled shifts in reduction potentials and kinetics, shedding light on their potential interactions with cellular reductant agents and protons. The weaker interactions of complexes 1 and 2 with BSA and DNA, together with their lower bioavailability and solubility compared to CQDP, contribute to our understanding of the potential biological effects of the chromium complexes studied. This abstract provides a comprehensive overview of the results of the study, highlighting the significance of the PCET reactions and their potential implications for biological processes and health effects.

The Successive Ionic Layer Adsorption and Reaction (SILAR) technique is a versatile method for depositing thin films with controlled thickness surfaces. However, achieving high-quality thin films with an optimal number of deposition cycles required to improve film properties applicable in photocatalysis is an important consideration. In this study, we investigate the influence of the number of cycles (3, 6, 9, 12, and 15 cycles) in the SILAR technique on the characteristic parameters, including the structural, morphological, and optical properties of deposited Ba/ZnO thin films on glass substrates. X-ray diffraction analysis reveals the hexagonal polycrystalline nature of Ba-doped ZnO films. The intensity of peaks increased with increasing of cycles number which the preferred orientation was (002), while the crystallite size decreasing from 11.105 to 10.904 nm. SEM shows grain size increasing from 29.71 to 44.79 nm as SILAR growth cycles rise from 3 to 15. The thin films' transmittance measurements ranged from 290 to 1200 nm. The thin films' energy band gaps decreased from 3.68 to 3.25. Additionally, the wettability of Ba-doped ZnO films increased with the number of SILAR cycles, rising from 21.23° at 3 cycles to 56.55° at 15 cycles. Furthermore, the photocatalytic performance of samples under visible sunlight was studied for methylene blue and amoxicillin at different cycle numbers. At 15 cycles, the degradation of methylene blue reached 93.51%, whereas amoxicillin was degraded by 54.31%. This study offers valuable insights into the influence of Ba-doped ZnO thin films with varying cycles on the quality of thin films, which is an applicable facility in photocatalytic degradation.

Graphical abstract

In this work, we discuss the effect of annealing temperature on the structural, morphological optical and photocatalytic properties of zinc oxide (ZnO) thin films prepared by using dip-coating technique on porous ceramic substrates at different annealing temperatures of 400 °C, 500 °C, 600 °C, and 700 °C for 2 h. The photocatalytic activity of the prepared ZnO photocatalysts was examined by evaluating the degradation of Orange II (OII) as a model of dyes under light irradiation. ZnO photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–visible absorption spectroscopy. SEM analysis revealed that the annealing temperatures greatly affected the grain size and the topography of ZnO surfaces. XRD results showed that all samples have a polycrystalline nature with a hexagonal wurtzite structure. The experimental data demonstrated that the average crystallite size of the prepared ZnO thin films varied from 15 to 24 nm with the increase of the annealing temperatures from 400 °C to 700 °C. The UV–Vis data indicated an enhancement in the absorbance of ZnO thin films across the ultraviolet range with increased annealing temperatures. The photodegradation rate increased to 94.7% by increasing the annealing temperatures.