Transition Metal Chemistry最新文献

Complexes (1–3) with nitrogen-based heterocyclic ligands were synthesized by reacting ruthenium precursor [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂ and ligands L1, L2 and L3. Upon reacting the complexes 1–3 with sodium azide, azido complexes 4–6 were obtained. These complexes as well as ligands were tested for anti-cancer activity where, ligand L2 was found to have lowest IC₅₀ value with stable interaction of ROCK-1 protein suggesting one of the possible mechanisms for complex’s anti-cancer activity.

Graphical Abstract

Half-sandwich ruthenium complexes 1–3 were synthesized and upon further reaction with sodium azide (NaN3) in methanol yielded azido ruthenium complexes 4–6. All the ligands and complexes were studied for anticancer activity. Anticancer activity assessed in human lung cancer cell line (A549) revealed that ligand L2 has the highest anti-cancer activity amongst the others studied.

Azido Ruthenium Complex 4

In this study, eco-friendly synthesis of Cu/CuO nanoparticles (Cu/CuO NPs) and Ag/Cu based composites was described. The leaf extract of Dendrophthoe falcata (D. falcata) which is rich in phenolic and flavonoid content was used as green reducing agent for Cu and Ag ions in aqueous solution. The biosynthesis of Cu/CuO NPs is an appealing alternative to physical and chemical approaches due to its low cost, simplicity, and environmental friendliness. Biosynthesized Cu/CuO NPs were characterized by UV–Visible spectroscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction (XRD), and transmission electron microscopy (TEM). Solid state UV–Visible analysis showed a broad band of absorption centered at 580 nm for Cu/CuO NPs. Powder XRD analysis confirmed the presence of FCC Cu(0) phase in the sample along with oxides of Cu and the crystallite size of Cu/CuO was 15.8 nm. Morphological analysis using TEM showed aggregated particles with size in range between 10–50 nm. Additionally, Ag/AgO NPs and Ag/Cu based composites were prepared using D. falcata leaf extract. All three biosynthesized materials were tested for inhibitory activity against Staphylococcus aureus, Bacillus thuringiencis, Escherichia coli, and Pseudomonas aeruginosa. In this study, Ag/Cu based composites showed activity against microorganisms classified as gram negative (Pseudomonas aeruginosa) and gram positive (Staphylococcus aureus and Bacillus thuringiencis). In contrast, Cu/CuO and Ag/AgO NPs were active against only a single species of gram positive bacteria. In conclusion, the biosynthesis of Cu/CuO NPs and Ag/Cu based composites described in this work is facile and the synthesized materials have the potential to be developed into antibacterial compositions that fight infectious microbes in the future.

Condensation of 8-hydroxy-2-quinolinecarbaldehyde and 3-bromoaniline, followed by reduction with NaBH₄, afforded a new potential tridentate ligand of 2-(((3-bromophenyl)amino)methyl)quinolin-8-ol (HL), which was characterized by NMR spectroscopies and mass spectrometry. Treatment of HL with zinc acetate or cadmium acetate using solvothermal method gave a dinuclear complex [Zn₂(κ²-N,O-L)₂μ-(κ²-N,O-L)₂]·2CH₄O (1) and a tetranuclear complex [Cd₄μ-(κ²-N,O-L)₄μ-(κ³-N,N,O-L)₂(κ²-O₂CCH₃)₂] (2), respectively. The crystal structures of complexes 1 and 2 were determined with single-crystal X-ray diffractions and powder X-ray diffractions, showing the good ligating property and rich coordination modes of the ligand L⁻. Moreover, the complexes 1, 2 were characterized by infrared, NMR, UV–vis spectroscopies and mass spectrometry.

In this work, four new aroylhydrazone-based Schiff base ligands (HL1-HL4) have been synthesized by the condensation of 2-(benzyloxy)benzoylhydrazine with four different aldehydes, namely cinnamaldehyde, 4-methylbenzaldehyde, 4-methoxybenzaldehyde, 4-allyloxybenzaldehyde. The correspondent bischelated Ni(II) complexes [Ni(L1)₂-Ni(L4)₂] were prepared in-situ by refluxing an ethanolic solution of 2-(benzyloxy)benzoylhydrazine with the aldehydes mentioned above in the presence of Ni(II) acetate tetrahydrate. The ligands and complexes were characterized by FT-IR, ¹H NMR, mass, and UV–visible spectroscopic techniques. The molecular structures of ligands HL1, HL2, and complex Ni(L3)₂ were determined by single crystal X-ray diffraction technique. In ligand HL1, the benzohydrazide moiety forms dihedral angles of 15.48 and 38.78° with the phenyl rings of the molecule. In contrast, the two independent molecules detected in the crystal of ligand HL2 slightly differ in their conformation, due to a different orientation of the benzyl ring that makes a dihedral angle of 29.54 and 49.25° with the benzohydrazide moiety. The metal ion in complex Ni(L3)₂ exhibits a distorted square-planar geometry with trans-configuration of the deprotonated benzohydrazide ligands coordinating Ni(II) through the azomethine-N and carbonylate-O atoms. The antioxidant activity of the ligands and complexes was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The ligands showed a low level of radical scavenging activity compared to the standard ascorbic acid, whereas the complexes did not show any activity. Moreover, the cytotoxicity of the synthesized compounds was tested in vitro against brine shrimp, and the results showed a promising cytotoxic effect of ligands and complexes.

Natural mineral composite catalysts have attracted much attention due to their great potential in the fields of water treatment, air purification and energy conversion. In this study, porous TiO₂ materials were synthesized from ilmenite by a two-stage calcination and acid leaching process, and porous TiO₂/CdS composites were prepared by a hydrothermal method. The results of photocatalytic experiments indicate that the porous TiO₂/CdS composite (PTC-2) with a Ti/Cd molar ratio of 1:1 exhibits the highest photocatalytic activity, with the degradation rate of methylene blue achieving a maximum value of 96.6% at 80 min. Moreover, the composite maintains a degradation efficiency of 88.5% after five cycles. The findings demonstrate that the TiO₂/CdS heterojunction significantly enhances the photocatalyst's absorption of visible light while facilitating the effective separation and transfer of photogenerated electron–hole (e⁻/h⁺) pairs. The porous architecture of the composite facilitates superior electron transport pathways and effectively mitigates e⁻/h⁺ recombination. Furthermore, a mechanism for the photocatalytic degradation of organic dyes using porous TiO₂/CdS composites is proposed, wherein photogenerated superoxide radicals (^·O₂⁻) and hydroxyl radicals (^·OH) serve as the primary reactive species. This study explores the cost-effective synthesis of TiO₂/CdS heterojunctions and makes a significant contribution to the advancement and utilization of natural minerals for pollution degradation.

It is of great practical significance to explore and prepare cheap, high-performance, and stable catalysts for oxygen reduction reaction (ORR), but it is still in progress at present. Herein, a straightforward evaporation–pyrolysis strategy is designed for the preparation of 3D porous electrocatalysts (denoted as (textrm{Fe}-textrm{Co}-textrm{NC}), which represented carbonization products at °C) made of carbon nanoparticles combined with metallic Fe-Co-doped N-enriched bridged carbon nanotube by carbonization of a pristine ZIF8 as highly efficient and durable ORR electrocatalysts. The obtained Fe–Co–NC structure possesses 3D open porous texture, abundant active sites, desired nitrogen bonding type, and high specific surface area, providing them with excellent ORR activity. The optimal performing (textrm{Fe}-textrm{Co}-textrm{NC}) catalyst presents an outstanding ORR performance in terms of a high onset potential ((textrm{E}_{text{ onset } })) of 0.96 V (vs. RHE) and half-wave potential ((textrm{E}_{1 / 2})) of 0.86 V (vs. RHE), respectively, possible to rival those of the commercially available (textrm{Pt} / textrm{C}) in an alkaline electrolyte solution. Besides, the (textrm{Fe}-textrm{Co}-textrm{NC}) catalyst manifests better stability than those of commercially available (textrm{Pt} / textrm{C}), which is of importance for the optimization and characterization of novel electrocatalysts originated from non-precious metals.

The current work describes the synthesis of two Cu(II) complexes [Cu(LA_I)₂] complex-1 and [Cu(LA_II)₂] complex-2 based on σ-donating acylpyarazolone ligands. Both complexes were thoroughly investigated using FTIR, UV–Vis, TGA and ESR spectroscopy methods. Additionally, single-crystal X-ray diffraction analysis was employed to determine their structures. The analysis indicates that the Cu²⁺ ion in both complexes occupies a centre of inversion symmetry and exhibits square-planar geometry. The examined complexes [Cu(LA_I)₂] complex-1 and [Cu(LA_II)₂] complex-2 crystallize in the P2₁/c Monoclinic and P2₁/n Monoclinic space groups, respectively, according to the X-ray single-crystal investigation. In addition to the experimental and spectroscopic investigations, DFT calculations were performed using the B3LYP functional with the LANL2DZ basis set for optimization. The bond lengths and bond angles determined from the DFT calculations are consistent with the X-ray data. HOMO–LUMO energy, natural bonding orbital and spin density analyses were also conducted to provide the best possible correlation and comparison with the experimental data. Intermolecular and non-covalent interactions were examined using Hirshfeld surface analysis. Furthermore, a cytotoxicity assay of the synthesized [Cu(LA_II)₂] complex-2 was performed against three different cancer cell lines: NCI-H23 (lung carcinoma cell line—lung cancer), SH-SY5Y (neuroblastoma cell line—neuroblastoma cancer) and HepG2 (hepatocellular carcinoma cell line—liver cancer), where notable cell death was observed, demonstrating the effectiveness of the complex against cancer cells.

Graphical abstract

We employed a cost-effective co-precipitation method to fabricate nanostructures of xCo:NiO where x values of cobalt 0.00, 0.02, 0.04, 0.06, and 0.08 were utilized. Our subsequent investigation included a thorough characterization of the resulting samples using various techniques, including Powder X-ray diffraction (PXRD), UV–Visible spectrophotometry (UV–Vis) and Fourier Transform Infrared spectroscopy (FTIR). Analysis of the PXRD data unveiled an average crystallite size spanning from 33 to 44 nm, determined through the application of the Scherrer formula. The XRD data were used to extract parameters such as lattice constant, cell volume, dislocation density, and microstrain. The application of the maximum entropy method allowed for an exploration of the electronic structure and interatomic bonding within the unit cell of cobalt-doped NiO. These investigations revealed that the incorporation of cobalt authenticates the covalent bond strength between nickel and oxygen, as evidenced by the mid-bond density values. Employing UV–Vis analysis, we determined the optical band gap (Eg) values and falls within the range of 3.210–3.316 eV. The FTIR findings revealed the existence of significant functional groups at various stages of the synthesis process.

A novel nanomagnetic recoverable catalyst has been developed from a copper (II) complex supported on the surface of Fe₃O₄ nanoparticles. In the initial step, Fe₃O₄@SiO₂ was functionalized with 4-aminobenzoic acid, chosen for its safety, cost-effectiveness, and environmentally friendly properties as an amine source. This was then reacted with benzo[d]thiazole-2-carbonyl chloride to immobilize the desired benzothiazole structure, serving as a ligand for Cu(II). The resulting catalyst, Fe₃O₄@SiO₂-ABA-Amide/BTH-Cu(II), was successfully synthesized and thoroughly characterized using a range of spectroscopic techniques, including FT-IR, SEM, TEM, EDX, TGA, XRD, VSM, and ICP-OES. This nanomagnetic copper catalyst exhibits high catalytic efficiency in the reduction of a broad library of nitro compounds to the desired amines. Using this eco-friendly catalytic system, a diverse range of aliphatic and aromatic amines was synthesized with good to excellent yields in a suitable time range. The Fe₃O₄@SiO₂-ABA-Amide/BTH-Cu(II) catalyst can be easily recovered using magnetic attraction and retains its effectiveness after being washed with an organic solvent and water. It demonstrated consistent performance across at least eight consecutive runs, highlighting its durability and efficiency. The ease of fabrication and straightforward process of magnetic separation are pivotal advantages of the current catalyst, making it highly effective for large-scale applications. One of its remarkable features is its excellent recyclability, which allows for up to eight repeated uses without significant loss in performance. Additionally, the catalyst demonstrates impressive yields of amine products, coupled with a high loading capacity of palladium onto the modified surface of magnetic nanoparticles. These characteristics collectively highlight the catalyst’s efficiency and practicality in various industrial applications.

Graphical abstract

The current study outlines the simple process of designing Au nanoparticles (NPs) under mild conditions using gelatin as a natural capping and reducing agent. Through the use of UV–Vis (ultraviolet–visible), FT-IR (Fourier transform infrared) spectroscopy, TEM (transmission electron microscopy), FE-SEM (field emission scanning electron microscopy), EDX (energy-dispersive X-ray spectroscopy), XRD (X-ray diffraction), and elemental mapping techniques, the formation of gold nanoparticles stabilized by gelatin (Au NPs@Gel) and their structural properties were investigated. Gelatin-capped Au NPs produced the spherical, lowest average particle sizes, ranging from 10 to 15 nm, according to the microscopic images. Additionally, Au NPs/Gelatin showed a notably high percentage of cytotoxicity when tested against common human endometrial cell lines, such as AN3-CA and HEC-1-A, but a very low percentage of toxicity when tested against normal cell lines. Au NPs@Gel showed the strongest anti-endometrial effects against the AN3-CA cell line. The DPPH (2,2-Diphenyl-1-picrylhydrazyl) experiment was employed to examine the antioxidant characteristics of the Au NPs@Gel bio-composite, with BHT (butylated hydroxytoluene) serving as the positive control. IC₅₀ of the Au NPs@Gel material was found to be 213.8 µg/mL in the DPPH assay. Antioxidant activity of the Au NPs@Gel was strongly correlated with its capacity to prevent endometrial cancer. According to the aforementioned results, Au NPs@Gel may be used to treat a variety of human cancers.