Transition Metal Chemistry最新文献

Artemisia indica, belonging to the family Asteraceae, is renowned for its rich phytoconstituents and traditional medicinal uses. This study aimed to optimize the green synthesis of biocompatible Ag NPs using varying concentrations of A. indica leaf extract and AgNO3. The objectives were to characterize the synthesized NPs and evaluate their potential biomedical applications. The synthesized NPs were characterized using FTIR, XRD, TEM, and Zeta sizer. The results indicated an average particle size of approximately 20 nm and a zeta potential of −23.4 mV, confirming their stability. PXRD analysis demonstrated the crystalline nature of the NPs, while FTIR analysis confirmed the capping of phytoconstituents on the nanoparticle surface. Biocompatibility was assessed using the MTT assay on the L929 cell line, showing 83% cell viability, indicating non-toxicity. Additionally, the green-synthesized NPs exhibited significant antibacterial activity at a concentration of 500 μg/mL, as evidenced by a clear zone of inhibition. This study highlights a rapid, eco-friendly synthesis method for Ag NPs, paving the way for novel biomedical applications.

Graphical Abstract

Poly(ethylene terephthalate) (PET) taken from postconsumer commercial water bottles was subjected to acid hydrolysis with HNO₃ to recover terephthalic acid (H₂TPA). The H₂TPA was submitted to mono-nitration with HNO₃/H₂SO₄ to produce 2-nitro-terephthalic acid (NO₂-H₂TPA) in good yield. Both compounds were well characterized by NMR (¹H; ¹³C; ¹H–¹³C HSQC). These two molecules were used as ligands for the syntheses of two new cobalt-based metal–organic frameworks (MOFs) via solvothermal methodology, in dimethylformamide (DMF) or dimethylacetamide (DMA). The MOFs Co-TPA-DMA (1) and Co-(NO₂-TPA)-DMF (2) were obtained and characterized by single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD) and scanning electron microscopy with energy-dispersive spectroscopy (SEM–EDS).

Co-precipitation method was used as a quick and effective way to elaborate the Mg and Cu co-doped TiO₂ (MgCu/T) nanoparticles. The formation of a single phase (anatase) with a tetragonal structure of nano-crystallized MgCu/T was confirmed by X-ray diffraction (Card No. 89–4203). Experimental results indicate that the synthesized MgCu/T nanoparticles are nanometric, ranging from 12 to 25 nm, consistent with the findings from SEM images. Additionally, the UV–Vis reflectance spectra showed that MgCu/T nanoparticles possess strong absorption properties in the UV–visible region. Hence, the photocatalytic activities showed that the 4 mol% Mg-doped MgCu/T nanoparticles exhibited the highest activity as a photocatalyst under ultraviolet light. The maximum degradation was found to be 58% for the sample 4 mol% Mg-doped MgCu/T nanoparticles after 210 min of UV light irradiation. The increase in AC conductivity of MgCu/T nanoparticles with higher Mg concentrations can be attributed to the fact that Mg doping introduces shallow donor states in TiO₂. These states can more easily donate electrons to the conduction band, thus increasing the charge carrier concentration.

The current study describes the use of an extremely effective adsorbent for the removal of dye from an aqueous solution. This work focuses on the prospective use of zinc-doped strontium titanate (Zn²⁺:ST) nano-powder to remove the malachite green (MG) from an aqueous medium. Optimization of experimental conditions to find the maximum dye adsorption is studied in detail. The Zn²⁺:ST nano-powder was synthesized using the low-temperature solution combustion method and extensively characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FTIR and UV–visible spectroscopy. PXRD analysis revealed a cubic structure of Zn²⁺:ST, closely matching ICDD card No. 35-734, indicating a space group of pm-3 m (No. 221). The average crystallite size was found to be 20–30 nm using the Scherrer formula. SEM images depicted the particles’ irregular shape. UV–visible spectroscopy showed the band gap of 3.1 eV and FTIR confirmed formation of M–O bond at 582 cm⁻¹ and 868 cm⁻¹ for SrO and ZnO, respectively. Optimal adsorption parameters were determined by varying dosage, stirring rate, and pH. Under these optimized conditions, for 10 ppm of stock solution, an impressive 98% adsorption efficiency was achieved with a 10 mg/L dose, 30-min contact time, and pH 10. Adsorption isotherms were fitted to the Langmuir model, showing a favorable correlation between experimental data and the model. This study provides valuable insights into the potential application of zinc-doped ST nano-powder for efficiently removing malachite green from water solutions.

Four ferrocenylimine alcohol compounds, [Fe(η⁵-C₅H₅){η⁵-C₅H₄CH=NCH(R)CH₂OH}] (R = Et, (R)-HL1, (S)-HL1; R = Bn, (R)-HL2, (S)-HL2), were synthesized by condensation reaction from ferrocenecarboxaldehyde and different chiral aminoalcohols. Reduction of HL1 and HL2 with sodium borohydride afforded four corresponding ferrocenyl secondary amine alcohol compounds, [Fe(η⁵-C₅H₅){η⁵-C₅H₄CH₂–NHCH(R)CH₂OH}] (R = Et, (R)-HL3, (S)-HL3; R = Bn, (R)-HL4, (S)-HL4). The crystal structures of (R)-HL1, (S)-HL1, (R)-HL2 and (S)-HL3·HCl were determined by single crystal X-ray diffraction. In addition, all compounds HL1–4 were characterized by ¹H NMR, ¹³C NMR, FT-IR, and UV–Vis spectroscopies.

This paper highlights the advantages of using the potentiometric titration technique as a valuable tool for studying the oxidation reaction of ascorbic acid by hexavalent chromium species in aqueous solutions. Particular attention was paid to the method of determining diagnostic points allowing the quantification of ascorbic acid in the sample under study. Additionally, the influence of experimental conditions, specifically the pH of the system and the concentration of the reactants, on the type of hexavalent chromium species involved in the interaction with ascorbic acid was analyzed. It has been shown that the method presented provides a simple, cost-effective, and rapid tool that can be widely used for the direct determination of ascorbic acid.

The increase in demand for products based on rare earth metals has increased because of their recent surge in usage. Additionally, primary sources of rare earth metals, such as bastnaesite, are scarce. Therefore, it is necessary to characterize secondary sources to explore the potential of other rare earth metal sources to overcome their scarcity. This study utilizes zircon tailings from zircon processing in Indonesia, which are the result of magnetic separation of zircon sand (magnetic particles). An analysis of the elemental and mineral composition, as well as the particle size distribution of the tailings, was conducted. The results revealed a significant ZrO₂ composition of 10.3%, with 14.11% CeO₂ and 11.47% Y₂O₃ as the major oxides. Additionally, ThO₂ was present at 2%, which could be considered for the processing of zircon tailings for rare earth metal refinement because of its radioactive properties. The mineral phases indicate that the tailings consist mainly of xenotime, monazite, and zircon. Additionally, a rare earth metal-bearing mineral, cerianite, is present. The concentration of rare earth metals is greater for larger particles, whereas that of zircon is greater for smaller particles. These findings can be used to determine the next steps in the rare earth metal purification or extraction process.

In this study, the kinetic and mechanistic studies of the substitution of chloride ligand of [(chloro)(2,6-bis(N-heterocyclic carbene)pyridine)Pd(II)]BF₄ complexes, namely Pd1, Pd2, Pd3 and Pd4, by thiourea nucleophiles viz Tu, Dmtu and Tmtu were investigated. The rate of chloride substitution of dicyclometalated complexes was monitored in aqueous media containing 20 mM LiCl using stopped-flow spectrophotometry as a function of concentration and temperature under pseudo-first-order conditions. The kinetic data fitted to the pseudo-first-order rate law, k_obs = k₂[Nu]. The rate of chloride substitution decreased in the order Pd1 ˃ Pd2 ˃ Pd4 ˃ > Pd3. The reactivity of Pd1 was lower by two orders of magnitude compared to [Pd(terpy)Cl]⁺ (terpy = terpyridine). Both complexes have strong π-acceptor non-leaving ligands that promote efficient back bonding of charge into the aromatic bis(NHC) chelates of its non-leaving ligand. Contrastingly, the lutidine-bridged complexes, (Pd2-4) form 6-membered and non-aromatic bis(NHC) chelates which cause steric influence on either side of the square plane. Their substituents also impart additional steric effects and σ-inductive effects in the rings. The combined effect significantly lowers rates of substitution. Consequently, Pd3 was the least reactive. The substitution mechanism is associative since no evidence of a mechanistic change over to the dissociative substitution was observed, despite the complexes coordinated with tridentates with two cis-σ-bound carbon donors.

ZnO nanorods were successfully synthesized by the microwave irradiation method in this project. The procedure verified the highest yields, least expense, and fastest synthesis of pure, fine-grained, single-phase ZnO nanorods; additionally, the procedure is ecologically friendly. Same-scale size nanorods displayed varying d-spacing values with the Hold time changed at a constant temperature of 150 °C in the microwave reactor, as supported by the TEM results. HRTEM pictures verified the ZnO nanorods’ perfect form. The quality of the nanoparticles’ crystallization was demonstrated by SAED patterns and data. The hexagonal wurtzite structure of ZnO nanorods is further supported by the matching of the diffraction rings in the SAED image with the peaks in the XRD pattern. Based on the data analysis, we concluded that the d-spacing values in ZnO nanorods at various nanometer scales increased. The absence of diffraction peaks from other contaminants indicated a high level of purity in ZnO samples. All the diffraction peaks were in good arrangement with those of the hexagonal structure of ZnO. Only the elements zinc (Zn) and oxygen (O) appeared in the EDX data, and the mass fraction was calculated. In the UV–visible absorbance spectrum, the absorbance peak located at the wavelength of 376 nm was the characteristic peak for hexagonal wurzite ZnO. The bandgap for ZnO nanorods held for one minute at a constant temperature of 150 °C is 3.24 eV; the binding energy gap for samples maintained for five minutes is 3.25 eV; and the binding energy gap for samples held for fifteen minutes is 3.28 eV, as determined by the UV–vis data. The presence of a peak at 432 cm⁻¹ at 1 min Hold Time ZnO nanorods FTIR data, 434 cm⁻¹ in 5 min Hold time ZnO nanorods FTIR data, and 451 cm⁻¹ proved a characteristic vibration of the Zn–O bond in the wurzite structure of ZnO. Therefore, at a constant temperature of 150 °C, the distinctive peaks of ZnO nanorods increased with variations in hold duration.

Single crystals of the dinuclear cyclam complex (1, 4, 8, 11-tetraazacyclotetradecane)-copper (ii) tetrachlorocuprate {[Cu(14-ane)]CuCl₄} (1) were prepared by soft chemistry. The powder, resulting from their grinding, was characterized by FTIR spectroscopy and functionalized using silica support materials MSN and halloysite H. The in vitro studies conducted on (1) formulated with MSN or halloysite H against kidney epithelial cell line (HK2) and renal cancer cell (RCC) lines (Caki-2, TW, LN78) demonstrated significant antiproliferative effects for both renal cell types. An increase in the apoptosis levels in the RCC lines underscoring the potential as an anticancer therapeutic agent was observed. These findings were corroborated by an in silico analysis aimed at exploring the ADMET profile of (1), indicating favorable aqueous solubility, brain penetration and druglikeness properties akin to FDA-approved VEGFR inhibitors such as sorafenib and cabozantinib. To gain deeper insights into the anticancer behavior of (1), molecular docking simulations against the vascular endothelial growth factor receptor VEGFR1 (PDB entry code 3HNG) were conducted. The evaluation of the interacting modes and binding sites in the 3HNG-(1) target–ligand complex revealed diverse hydrogen-bonding interactions within the receptor’s binding pocket, suggesting a promising inhibition potential of (1) against VEGFR1.