Applied Organometallic Chemistry最新文献

Given the adverse effects of conventional chemotherapeutic agents, natural compounds and biocompatible materials have garnered growing interest in cancer therapy. Our previous research demonstrated that zinc oxide nanoparticles (ZnO NPs), synthesized through an ultrasound-mediated green method using coffee leaves, functioned as effective nanocarriers for the controlled release of mangiferin (MGF). Here, we investigated the anticancer activity of MGF, ZnO NPs, and MGF-loaded ZnO NPs (MGF-ZnO NPs) on HepG2 and Caco-2 cells, along with their underlying anticancer mechanisms. We found that both ZnO NPs and MGF-ZnO NPs significantly reduced cell viability and increased the extracellular to intracellular pH ratio (pHe/pHi) and reactive oxygen species levels in HepG2 and Caco-2 cells. MGF-ZnO NPs further induced notable morphological changes and enhanced cell membrane permeability, chromatin condensation, and nuclear lysis. Additionally, both ZnO NPs and MGF-ZnO NPs increased the overall apoptotic rate in cancer cells, with MGF enhancing the cytotoxic effects of MGF-ZnO NPs. Molecular docking analysis revealed that MGF-ZnO NPs may disrupt cell membrane biogenesis by inhibiting the biological activity of choline/ethanolamine phosphotransferase 1 (CEPT1), an enzyme involved in phospholipid synthesis, through hydrogen bonding and hydrophobic interactions. Additionally, MGF-ZnO NPs also exhibited strong binding affinity to DNA bases through hydrogen bonds (DC15(B) and DG12(A)) and hydrophobic interactions (DC23(B), DG22(B), DA18(B), DA17(B), and others), potentially compromising DNA function. This study suggests that loading ZnO NPs with MGF is a promising approach to enhance cancer therapy and underscores the complex mechanisms involved in nanotherapeutic action.

Green hydrogen serves as a crucial renewable energy source driving the transition of energy structures and advancing sustainable development. Photocatalytic technology represents one of the prominent approaches for green hydrogen production. Compared to traditional semiconductors, noble metal single-atom catalysts (SACs) have emerged as promising photocatalysts due to their high atomic utilization efficiency and superior catalytic activity. In this work, Pt and Pd single atoms were separately anchored onto oxygen vacancies (Vo) on the TiO₂ surface via a facile photodeposition method, yielding Pt or Pd monometallic single-atom loaded catalysts (Pt SAs/Vo-TiO₂ and Pd SAs/Vo-TiO₂). The optimal photodeposition time was investigated. Results demonstrate that the hydrogen evolution rate of Pt SAs/Vo-TiO₂ reached 2375.76 μmol h⁻¹ g_cat.⁻¹, while that of Pd SAs/Vo-TiO₂ achieved 1875.72 μmol h⁻¹ g_cat.⁻¹. These values are 76.5-fold and 60.4-fold higher than that of pristine TiO₂, respectively. Density functional theory (DFT) calculations reveal that the introduction of single atoms reduces the band gap of the catalyst, consistent with the experimental findings. This study provides optimal parameters for synthesizing efficient single-atom catalysts.

Chromium is an essential trace element that exerts antidiabetic effects by enhancing insulin sensitivity and upregulating key proteins and genes involved in glucose uptake and metabolism. The antidiabetic potential of chromium nanoparticles (CrNPs) and Adiantum capillus-veneris has been studied separately; however, the conversion of chromium into biogenic CrNPs using the plant extract and the evaluation of their effects on carbohydrate-hydrolyzing enzymes remain unexplored. In this study, CrNPs were synthesized using A. capillus-veneris extract, characterized through various instrumental techniques and evaluated for their antioxidant and antidiabetic potential in vitro. The optimal synthesis was achieved at a 4:9 (v/v) ratio of plant extract to chromium salt. The synthesized CrNPs were crystalline, irregular to round in shape, with sizes ranging from 58 to 90 nm, thermally stable up to 280°C, and exhibited a strong absorbance peak in the UV–Vis range at 420 nm. EDX analysis confirmed the presence of chromium at ~0.6 keV. The resulting CrNPs showed excellent antioxidant (DPPH, IC₅₀ = 100 μg/mL; ABTS, IC₅₀ = 125 μg/mL) and notable inhibition of carbohydrate-hydrolyzing enzymes; α-amylase (91.3% inhibition at 1000 μg/mL, IC₅₀ = 127 μg/mL) and α-glucosidase (86.4% inhibition at 1000 μg/mL, IC₅₀ = 140 μg/mL). CrNPs exhibited stronger biological potentials and outperformed both the aqueous and methanolic extracts of A. capillus-veneris plant, as well as chromium chloride hexahydrate in the antioxidant and antidiabetic assays. In conclusion, these activities are likely due to enhanced bioavailability and polyphenol–enzyme interactions, which significantly improved the activity of chromium chloride hexahydrate upon its conversion into CrNPs. Further validation in experimental diabetic models is warranted.

Photochromic dysprosium single-molecule magnets (Dy-SMMs) not only possess excellent intrinsic magnetic properties but also facilitate the preparation of intelligent devices owing to the integration of photochromism. However, related cases are still limited up to now. Herein, we report two photochromic polynuclear Dy-SMMs, [Et₃NH][Dy₄(ana)₉(OH)₄(CH₃CN)₂(H₂O)]·solvents (1; Hana = anthracene-9-carboxylatic acid) and [Et₃NH]₂[Dy₆(Tox)₄(aca)₁₂(OH)₂(CH₃OH)₂]·solvents (2; Tox⁻ = N-TEMPO oxamate ion). They have tetrahedral [Dy₄(OH)₄]¹²⁺ and double-layered cage-like [Dy₆(Tox)₄ (OH)₂]¹²⁺ cores, respectively, which are ligated by ana⁻ ligands into tetra- and hexa-nuclear cluster structures. Both 1 and 2 exhibit zero-field single-molecule magnet (SMM) behavior featuring a single magnetic relaxation process, which evolved into dual-relaxation processes upon the application of external dc fields. They also exhibit expected photochromic behaviors. The emergence of new peaks in the UV–Vis spectra and the quenching of photoluminescence (PL) emission peaks suggest that their photochromism could be attributed to the photogeneration of radical species in the systems.

The Pd-PEPPSI-NHC complexes (PEPPSI = pyridine-enhanced precatalyst preparation stabilisation initiation, NHC = N-heterocyclic carbene) have been widely applied in the Pd-catalyzed cross-coupling reactions. Further studies on the structures of Pd-PEPPSI-NHC complexes have shown that not only the NHCs, the ancillary ligands surrounding the Pd centre also play important roles in their catalytic reactions. For this purpose, a series of Pd-PEPPSI-NHC analogues bearing cycloalkane ring-fused pyridines (CA-Py) as the ancillary ligand were readily prepared and characterized by ¹H NMR, ¹³C NMR, elemental analysis and x-ray crystallography. The catalytic activities of the well-defined Pd–NHC complexes have been evaluated with respect to Suzuki–Miyaura cross-coupling reactions of aryl boronic acids with aryl chlorides and acyl chlorides, respectively.

Microbial drug resistance has become a global health concern, necessitating the quest to discover new and more effective drugs to combat this problem. This study focuses on synthesizing and evaluating the antimicrobial efficacy of metal complexes of theobromine-derived carbohydrazone as potential antimicrobial agents (M = Cd²⁺, Co²⁺, Cr³⁺, Cu²⁺, and Zn²⁺). The compounds were characterized by conductivity, elemental analysis, Fourier transform infrared, ¹H– and ¹³C–nuclear magnetic resonance, and electronic spectral data. The ligand and the metal complexes were screened for their antibacterial and antifungal activity against five microbial strains: Staphylococcus aureus, Streptococcus faecalis, Escherichia coli, Salmonella paratyphimurium, and Candida albicans. The molar conductivity revealed that the complexes are nonelectrolytes in dimethylsulfoxide (DMSO). In addition, the infrared spectral data indicated bidentate coordination of the theobromine carbohydrazone ligand through the carbonyl and the amino NH₂ group. The amino group w however, noncoordinating in the Ni (II) and Co (II) complexes. The theobromine-derived carbazone and its metal complexes exhibited moderate inhibitory activity against the tested microbial strains, with compound 4 (chromium complex) having the lowest MIC value of 0.38 μg/mL against both S. faecalis and C. albicans.

A set of vanadium complexes chelated by one thiophenoxyimine ligand in the form of [κ_N,S-(ArN=CHRS)]VCl₂(THF)₂ (R = C₆H₄, Ar = 2,6-Me₂Ph, 2a; Ar = 2,6-Et₂Ph, 2b; Ar = 2,6-ⁱPr₂Ph, 2c; R = 2,4-^tBu₂C₆H₂, Ar = 2,6-Me₂Ph, 2d; Ar = 2,6-ⁱPr₂Ph, 2e) were prepared in the yields of 30%–73% by the direct insertion of elemental sulfur into the carbon–lithium bond of the ligand-precursors and subsequent addition of 1 equiv. of VCl₃(THF)₃. Similar reactions using 0.5 equiv. of VCl₃(THF)₃ afforded the bis-ligated complexes [κ_N,S-(ArN=CHRS)]₂VCl (R = C₆H₄, Ar = 2,6-Me₂Ph, 3a; Ar = 2,6-Et₂Ph, 3b; Ar = 2,6-ⁱPr₂Ph, 3c; R = 2,4-^tBu₂C₆H₂, Ar = 2,6-Me₂Ph, 3d; Ar = 2,6-ⁱPr₂Ph, 3e) in moderate to good yields (35–86%). These vanadium complexes were characterized by elemental analysis as well as IR spectra. The structures of complexes 2a, 2b, and 3a were established by x-ray crystallography analysis. When activated with Et₂AlCl, the monoligated complexes 2a–2e exhibited very high catalytic activity for ethylene polymerization (up to 2.94 × 10⁸ g PE/mol(V)·h⁻¹) in the presence of ethyl trichloroacetate (ETA), which is superior to the analogous phenoxyimino vanadium complexes under the same conditions. Bis-ligated complexes 3a–3e produced relatively lower catalytic activities compared to monoligated analogs.

This study explores the electrochemical detection of imidacloprid (IMD) using a nickel-based metal–organic framework-modified glassy carbon electrode (Ni-MOF/GCE). Differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were employed to assess the electrode's performance for electrochemical sensing of IMD. The synthesized Ni-MOF was characterized using various analytical techniques such as x-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscope, and energy dispersive spectroscopy. The DPV analysis at pH 8 demonstrated a clear catalytic redox response with a limit of detection (LOD) of 67.7 nM. Repeatability tests confirmed the electrode's reliability, and stability tests indicated significant detection capability even after 1 month. The EIS (Bode plot) effectively distinguishes IMD concentrations, yielding a LOD of 19.5 nM. These results suggest that both DPV and EIS techniques offer practical solutions to detect IMD. The Ni-MOF/GCE electrode exhibits excellent potential for sensitive and reliable IMD detection, highlighting its applicability in environmental monitoring and paving the way for further development of Ni-MOF-based biosensors.

Increasing the accumulation of reactive oxygen species (ROS) is an important strategy for the anti-proliferative effects of many anti-cancer drugs. Herein, five novel organotin complexes were designed and synthesized, including three tri-organotin complexes [R₃SnL]_n (R = Me 1, Ph 2, n-Bu 3; HL = (7-hydroxy-2-oxo-2H-chromen-4-yl)acetic acid) and two di-organotin complexes [(Me₂Sn)₄L₂(μ₃-O)₂(CH₃O)₂] (4) and [(n-Bu₂Sn)₄L₂(μ₃-O)₂CH₃O]_n (5). These complexes were characterized by single crystal X-ray diffraction, NMR (¹H, ¹³C, and ¹¹⁹Sn), and infrared spectroscopy. The monocrystalline structure showed that complexes 1–3 displayed a 1D chain structure. Complex 4 exhibited a monomeric structure, whereas complex 5 featured a 1D chain structure containing tetranuclear Sn₄O₄ moieties. Complexes 2 and 3 showed strong anti-cancer activity against four tested tumor cells, with IC₅₀ values ranging from 1.63 to 3.69 μM. Furthermore, studies on the anti-cancer mechanism revealed that complex 2 induced mitochondrial membrane potential collapse in HeLa cells, triggered excessive ROS production, led to oxidative stress in cells, and ultimately resulted in apoptosis. Additionally, molecular docking studies were conducted on complex 2 with DNA and BSA, revealing binding energies of −7.16 and −7.30 kcal/mol, respectively. These results indicated its capacity to interact with these biomolecules. This research provides important data for the further development of new and highly effective anti-cancer drugs based on ROS regulation.