Transition Metal Chemistry最新文献

This research study shows that naturally occurring goethite-rich iron ore from the Tebessa region of Algeria can be positioned as a sustainable and cost-effective alternative for water treatment and natural catalyst development. This locally sourced and naturally occurring iron ore promotes a heterogeneous Fenton-like reaction for the decolorization of brilliant green (BG) dye under neutral pH conditions. The iron ore sample was collected and processed using cost-effective laboratory preparation methods. The treated iron ore sample has been thoroughly characterized in terms of composition, structure, and morphology revealing that the natural iron ore consists mainly of goethite (59%), with minor amounts of quartz, illite, and kaolinite. Further analysis showed that the studied ore exhibits mesoporous properties with a BET-surface area of 45 m²/g. UV–Vis diffuse reflectance spectroscopy confirmed the presence of iron oxide minerals, notably goethite and hematite phases. Indeed, we investigated the decolorization rate of BG dye solution using different concentrations of H₂O₂ activated with different doses of goethite-rich iron ore catalyst at 25 °C and 45 °C. During this heterogenous process, several kinetic models were examined. Preliminary experiments revealed that the optimal conditions for achieving 95% BG dye decolorization were a dye concentration of 10 mg/L, an H₂O₂ concentration of 3.0 mM, and an iron ore catalyst dose of 0.2 g/L, all within a reaction time of 2 h. This work may contribute to advance the use of natural catalysts in the challenging task of decolorization of other dyes.

Three new mononuclear Zn^II and Cd^II complexes have been designed and synthesized by using 2-phenoxyaniline Schiff base as ligands. Complexes 1–3 have been characterized by elemental analysis, FT-IR, ¹H NMR, and single-crystal X-ray diffraction. The structures of complexes 1–3 were analyzed by single-crystal X-ray diffraction, and intermolecular hydrogen bonds (C–H···Cl and π···π stacking) were found to connect the mononuclear molecules, forming supramolecular structures. The relationships between their photophysical properties and structures were studied by UV–visible absorption spectroscopy and fluorescence spectroscopy. The maximum emission wavelengths of complexes 1–3 in solid state vary within the range of 494–533 nm, and they emit bright yellow-green fluorescence under UV lamp irradiation. These properties indicate that these complexes can be used as potential fluorescent materials. Also, the molecular orbital densities and different energy levels are obtained by using the density functional theory methods.

Three metal organic frameworks [Cu₃(tpyc)₃(H₂btc)(Hbtc)·5H₂O]_n (1) [Mn(tpyc)(H₂O)₂·ClO₄]_n (2) and [Mn(tpyc)(bdc)_0.5(H₂O)]_n (3) have been synthesized by using 2,2′:6′2′′-terpyridine-4′-carboxylic acid (Htpyc) in the presence of different auxiliary ligands (H₃btc = 1,3,5-benzenetricarboxylic acid, H₂suc = succinic acid, H₂bdc = 1,4-benzene dicarboxylic acid) under solvothermal conditions. They were analyzed by elemental analysis, FT-IR, X-ray single crystal diffraction, PXRD and TGA. The results show that MOF 1 displays a 1D chain structure, which is further assembled to a 3D architecture via multiple intermolecular hydrogen bonds. MOF 2 also presents a 1D chain structure and the adjacent chains are further connected by hydrogen bonds O1–H1B∙∙∙O2#1, finally forming a 2D layered structure. For MOF 3, its 3D framework structure is formed by hydrogen bond O5–H5A∙∙∙O2#1 and O5–H5B∙∙∙O3#2 interaction between adjacent 1D chains. Furthermore, dye adsorption studies indicate that MOF 3 can selectively adsorb organic dye Congo red.

Due to the potential applications of bioactive compounds, two isomorphous mononuclear coordination polymers [M(pydc)(H₂O)]_n (M = Cd (1), Mn (2), H₂pydc = 5-hydroxypyrazine-2-carboxylic acid) were synthesized and fully characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy and powder X-ray diffraction analysis. Complexes 1 and 2 are six-coordinated motifs and exhibit slightly deformed octahedral geometry, which extends into three-dimensional frame structures. Complexes 1 and 2 interact with calf thymus DNA (CT-DNA) through intercalation, hydrogen bonding and van der Waals forces. Both complexes had good binding propensity for bovine serum albumin (BSA) with a relatively high binding constant (10⁴ L mol⁻¹) superior to that of H₂pydc (10³ L mol⁻¹). The interactions between H₂pydc, complexes 1 and 2 and BSA were static quenching procedures. Site competition experiments showed that the ligands and complexes interact with BSA at site II.

Four Fe(II) complexes, 1–3 and R1 with differently substituted tpy ligands were synthesized and characterized by a set of analytical techniques including 1D (¹H, ¹³C, 135-¹³C DEPT-135), 2D (¹H-¹H COSY) NMR spectroscopies and high-resolution mass spectrometry (HRMS). The ability of each compound to bind DNA was assessed by UV–visible titration assays using DNA extracted from Pisum sativum (split peas). UV–visible titration tests were performed to ascertain the binding affinity of these complexes with DNA, and the results indicated that the complexes are groove binders with binding constants in the range of 1.23–2.66 × 10⁴. To confirm that the complexes were binding with DNA through groove-binding, molecular docking studies using 1 and 2 with Dickerson-drew dodecamer B-DNA structure (PDB ID: 1B-DNA) were carried out which showed compatibility with the experimental data.

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.