Applied Organometallic Chemistry最新文献

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.

In this work, low-metal cerium-supported biochar composite catalytic materials (Ce_3.0-NC) were successfully prepared by the hydrothermal synthesis method. It was confirmed by characterization methods such as XRD, HR-TEM, Raman, and EPR that Ce_3.0-NC has excellent catalytic activity and structural stability. This catalyst efficiently catalyzes the synthesis of three types of nitrogen-containing heterocyclic derivatives in aqueous phase or water/ethanol mixed solvents under low-temperature and short-time conditions: tetraketones (yield 75%–99%), quinolines (yield 76%–99%), and quinoxalines (yield 42%–90%). The reaction system does not require a protective atmosphere or alkaline reagents, and has the advantages of mild conditions, green solvents, and high catalytic efficiency. After 7 cycles of use, there was no significant decline in Ce_3.0-NC catalyst activity. This study provides a new approach for the high-value utilization of biomass carbon from medicinal residue, achieving the green preparation of low-load metal-doped biochar and the efficient synthesis of nitrogen-containing heterocyclic compounds.

In this present study, we report the design and synthesis of a new Schiff base–linked silane derivative (Compound 7) via an efficient click reaction, fully characterized by ¹H and ¹³C NMR, mass spectrometry, and FT-IR spectroscopy. The triazole moiety of Compound 7 exhibited exceptional selectivity for Ni (II), achieving impressively low detection limits (LOD) of 5.2 × 10⁻⁷ M (UV–Vis) and 6.37 × 10⁻⁸ M (fluorescence). When immobilized on iron nanoparticles via the Stöber method, the resulting hybrid nanoparticle complex (H-NPs) demonstrated enhanced sensing performance, with LODs of 5.5 × 10⁻⁸ M (UV–Vis) and 1.68 × 10⁻⁸ M (fluorescence). The Stern–Volmer constants were determined to be 2.796 × 10⁸ for Compound 7 and 8.15 × 10⁷ for H-NPs, highlighting the superior quenching efficiency of the hybrid system. Beyond sensing, Compound 7 displayed significant anticancer activity against the HeLa cell line, while molecular docking studies revealed strong interactions with the 3HB4 protein (binding energy −8.04 kcal/mol), indicating a stable ligand–protein complex. Overall, these findings showcase Compound 7 as a versatile chemosensor with remarkable potential for Ni (II) detection in environmental, agricultural, and biomedical applications, combining sensitive detection, nanoparticle hybridization, and therapeutic potential in a single platform.